阅读说明：本技术 模块化排气再循环混合器 (Modular exhaust gas recirculation mixer ) 是由 D·B·马斯特伯根 D·切拉 G·J·汉普森 Y·韩 J·P-C·邱 D·里昂 H·D· 于 2020-02-07 设计创作，主要内容包括：一种模块化排气再循环混合器系统,包括：排气壳体,排气壳体包括进入排气壳体的内部(228)的排气入口(212)；混合器壳体(210)；会聚喷嘴模块(202),会聚喷嘴模块被接纳在混合器壳体中且在从混合器的空气入口(204)到混合器的出口(206)的流动路径中,会聚喷嘴朝向混合器的出口会聚；会聚－发散喷嘴模块(214),会聚－发散喷嘴模块被接纳在混合器壳体中并且包括流体连通的空气－排气入口(230),以接收来自会聚喷嘴和排气壳体内部的流体流。(A modular exhaust gas recirculation mixer system, comprising: an exhaust housing including an exhaust inlet (212) into an interior (228) of the exhaust housing; a mixer housing (210); a converging nozzle module (202) received in the mixer housing and converging toward the outlet of the mixer in a flow path from an air inlet (204) of the mixer to an outlet (206) of the mixer; a converging-diverging nozzle module (214) received in the mixer housing and including an air-exhaust inlet (230) in fluid communication to receive a fluid flow from the converging nozzle and the exhaust housing interior.)

1. An exhaust gas recirculation mixer system, comprising:

an exhaust housing including an exhaust inlet into an interior of the exhaust housing;

a mixer housing;

a converging nozzle in the mixer housing and in a flow path from an air inlet of a mixer to an outlet of the mixer, the converging nozzle converging toward the outlet of the mixer;

a converging-diverging nozzle in the mixer housing and comprising an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and the exhaust housing interior;

a first nozzle module configured to be received in the mixer housing and to define at least a portion of the converging nozzle or the converging-diverging nozzle when received in the mixer housing; and

a second nozzle module configured to be received in the mixer housing when the first nozzle module is not in the mixer housing, the second nozzle module configured to define at least a portion of the converging nozzle or the converging-diverging nozzle when received in the mixer housing, and the second nozzle module having different flow characteristics than the first nozzle module.

2. The exhaust gas recirculation mixer system of claim 1, wherein the first nozzle module defines a portion of the converging nozzle.

3. The exhaust gas recirculation mixer system of any of the preceding claims, wherein the second nozzle module defines a portion of the converging-diverging nozzle.

4. The exhaust gas recirculation mixer system of any of the preceding claims, wherein an inlet of the converging-diverging nozzle is positioned to receive an air-exhaust-fuel mixture.

5. The exhaust gas recirculation mixer system of any one of the preceding claims, further comprising:

a first pressure port positioned at a converging end of the converging nozzle, the first pressure port providing a location to sense a first pressure at the converging end of the converging nozzle.

6. The exhaust gas recirculation mixer system of claim 5, further comprising:

a second pressure port upstream of the converging portion of the converging nozzle, the second pressure port providing a location to sense a second pressure upstream of the converging nozzle.

7. The exhaust gas recirculation mixer system of any of claims 5-6, further comprising:

a third pressure port positioned in a throat of the converging-diverging nozzle, the third pressure port providing a location to sense a third pressure within the throat of the converging-diverging nozzle; and

a fourth pressure port positioned downstream of the diverging portion of the converging-diverging nozzle, the fourth pressure port providing a location to sense a third pressure downstream of the converging-diverging nozzle.

8. The exhaust gas recirculation mixer system of any one of the preceding claims, further comprising:

a liquid passage defined by the converging-diverging nozzle, the liquid passage having an inlet positioned between the converging nozzle and the converging-diverging nozzle, the liquid passage positioned and sized to direct and regulate liquid drippings toward an outlet of the exhaust gas recirculation mixer.

9. The exhaust gas recirculation mixer system according to any one of the preceding claims, wherein an inner surface of an inner receiver cavity is non-circular having a larger radius along an upper portion of the inner receiver cavity than a lower portion of the inner receiver cavity.

10. The exhaust gas recirculation mixer system according to any one of the preceding claims, wherein a throat of the converging-diverging nozzle has a larger cross-sectional area than a converging end of the converging nozzle.

11. The exhaust gas recirculation mixer system according to any one of the preceding claims, wherein the cross-sectional area of the throat of the converging-diverging nozzle is 1.1-3 times greater than the cross-sectional area of the converging end of the converging nozzle.

12. A method, comprising:

receiving a plurality of identical exhaust mixer housings;

inserting a first set of nozzle modules into a first set of a plurality of substantially identical exhaust mixer housings to create a first converging nozzle and a converging-diverging nozzle arrangement; and

inserting a second set of nozzle modules into a second plurality of identical exhaust mixer housings to create a second different converging nozzle and converging diverging nozzle arrangement.

13. The method of claim 12, wherein the first set of nozzle modules is a set of converging nozzles.

14. The method of claim 12, wherein the first set of nozzle modules is a set of converging-diverging nozzles.

15. The method of claim 12, wherein the second converging nozzle and converging-diverging nozzle arrangement have different flow characteristics than the first converging nozzle and converging-diverging nozzle arrangement.

16. The method of claim 15, wherein the second set of nozzle modules comprises a second set of converging-diverging nozzles having a different throat cross-sectional area than the first set of nozzles.

17. The method of claim 15, wherein the second set of nozzle modules comprises a second set of converging nozzles having a different converging end cross-sectional area than the first set of nozzles.

18. An engine system, comprising:

an intake manifold configured to receive a combustible mixture configured to be combusted within a combustion chamber;

a throttle upstream of the intake manifold, the throttle configured to at least partially regulate air flow into the intake manifold;

an exhaust manifold configured to receive combustion products from the combustion chamber; and

an exhaust gas recirculation mixer system downstream of the throttle valve and upstream of the intake manifold, the exhaust gas recirculation mixer comprising:

an exhaust housing including an exhaust inlet into an interior of the exhaust housing;

a mixer housing;

a converging nozzle in the mixer housing and in a flow path from an air inlet of a mixer to an outlet of the mixer, the converging nozzle converging toward the outlet of the mixer;

a converging-diverging nozzle in the mixer housing and comprising an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and the exhaust housing interior;

a first nozzle module configured to be received in the mixer housing and to define at least a portion of the converging nozzle or the converging-diverging nozzle when received in the mixer housing; and

a second nozzle module configured to be received in the mixer housing when the first nozzle module is not in the mixer housing, the second nozzle module configured to define at least a portion of the converging nozzle or the converging-diverging nozzle when received in the mixer housing, and the second nozzle module having different flow characteristics than the first nozzle module.

19. The engine system of claim 18, wherein the recirculation mixer comprises:

a first pressure port positioned upstream of the converging nozzle, the first pressure port providing a location to sense a first pressure upstream of the converging nozzle; and

a second pressure port positioned at the converging end of the converging nozzle, the second pressure port providing a location to sense a second pressure at the converging end of the converging nozzle.

20. The engine system of claim 19, wherein the recirculation mixer comprises:

a third pressure port positioned in a throat of the converging-diverging nozzle, the third pressure port providing a location to sense a third pressure within the throat of the converging-diverging nozzle; and

a fourth pressure port positioned downstream of the converging-diverging nozzle, the fourth pressure port providing a location to sense a third pressure downstream of the converging-diverging nozzle.

21. The engine system of claim 20, further comprising a controller, the controller comprising:

one or more processors; and

a non-transitory computer readable storage medium coupled to the one or more processors and storing program instructions for execution by the one or more processors, the program instructions instructing the one or more processors to:

determining a first pressure differential between a first pressure location positioned upstream of the converging nozzle and a second pressure location positioned at a converging end of the converging nozzle;

determining an air mass flow rate based on the determined first pressure differential;

determining a second pressure differential between a third pressure location positioned in the throat of the converging-diverging nozzle and a fourth pressure location positioned downstream of the converging-diverging nozzle; and is

Determining an air-fuel-exhaust flow rate based on the measured second pressure differential.

22. The engine system of any one of claims 18-21, further comprising:

a crankcase in the engine block;

a first conduit fluidly connecting the crankcase to a point upstream of the throttle valve; and

a second conduit fluidly connecting the crankcase to a point downstream of the throttle, a pressure differential across the throttle causing air to flow through the crankcase.

23. The engine system of claim 22, wherein the second conduit is fluidly connected to the exhaust gas recirculation mixer upstream of the converging-diverging nozzle and downstream of the converging nozzle.

Technical Field

The present disclosure relates to Exhaust Gas Recirculation (EGR) systems for internal combustion engines.

Background

Exhaust Gas Recirculation (EGR), particularly cooled EGR (creg), may be added to internal combustion engine systems to reduce NOx emissions and reduce knock propensity. In such systems, a quantity of exhaust gas is added to the air and/or fuel mixture within the engine intake manifold. The challenge is the cost of delivering cEGR, especially for high efficiency engines, which is typically most efficient when the exhaust manifold pressure is lower than the intake manifold pressure. This pressure differential across the engine creates a positive scavenging pressure differential that sweeps combustion gases from the cylinder well (cylinder well) and provides advantageous pressure-volume pumping circuit operation. It is particularly challenging to deliver cEGR from a source at the exhaust manifold to the intake manifold without negatively impacting engine cycle efficiency and residual gas scavenging via the pumping circuit. The "classical" high pressure loop cEGR system delivers exhaust gas directly (plumbs) to the intake manifold, which requires design or variable turbocharging to force the engine exhaust manifold pressure higher than the intake manifold, which in turn can disadvantageously reduce scavenging of hot combusted gases and engine P-V cycling, with loss of efficiency. This is particularly true because the purpose of cEGR is to reduce the tendency for knock, to improve efficiency and power density. However, this classical approach to driving EGR actually increases the tendency for knock through retention of residual gases and reduces efficiency through negative pressure work of the engine in a diminishing return manner, i.e., reducing knock through categ has two positive points but one negative point due to its pumping pattern, resulting in a zero gain point where the cost of driving categ offsets the benefits of delivering categ.

Disclosure of Invention

The present disclosure describes technologies relating to recirculating exhaust gases.

An exemplary embodiment of the subject matter described in this disclosure is an exhaust gas recirculation mixer system having the following features. The exhaust housing includes an exhaust inlet into an interior of the exhaust housing. The converging nozzle is in the mixer housing and in a flow path from an air inlet of the mixer to an outlet of the mixer. The converging nozzle converges towards the outlet of the mixer. The converging-diverging nozzle is in the mixer housing and includes an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and an interior of the exhaust housing. The first nozzle module is configured to be received in the mixer housing and, when received in the mixer housing, defines at least a portion of a converging nozzle or a converging-diverging nozzle. The second nozzle module is configured to be received in the mixer housing when the first nozzle module is not in the mixer housing. The second nozzle module, when received in the mixer housing, is configured to define at least a portion of a converging nozzle or a converging-diverging nozzle. The second nozzle module has a different flow characteristic than the first nozzle module.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The first nozzle module defines a portion of a converging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second nozzle module defines a portion of a converging-diverging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The inlet of the converging-diverging nozzle is positioned to receive the air-exhaust-fuel mixture.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The first pressure port is positioned at the converging end of the converging nozzle. The first pressure port provides a location to sense a first pressure at the converging end of the converging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second pressure port is upstream of the converging portion of the converging nozzle. The second pressure port provides a location to sense a second pressure upstream of the converging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The third pressure port is positioned in the throat of the converging-diverging nozzle. The third pressure port provides a location to sense a third pressure within the throat of the converging-diverging nozzle. The fourth pressure port is positioned downstream of the diverging portion of the converging-diverging nozzle. The fourth pressure port provides a location to sense a third pressure downstream of the converging-diverging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The liquid passage is defined by a converging-diverging nozzle. The liquid channel has an inlet positioned between the converging nozzle and the converging-diverging nozzle. The liquid passage is positioned and sized to direct and regulate liquid dripping toward the outlet of the exhaust gas recirculation mixer.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The inner surface of the inner receiver cavity is non-circular with a larger radius along an upper portion of the inner receiver cavity than a lower portion of the inner receiver cavity.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The throat of the converging-diverging nozzle has a larger cross-sectional area than the converging end of the converging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The cross-sectional area of the throat of the converging-diverging nozzle is 1.1-3 times greater than the cross-sectional area of the converging end of the converging nozzle.

Exemplary embodiments of the subject matter described in this disclosure are methods having the following features. Receiving the same exhaust mixer housing. A first set of nozzle modules is inserted into a first set of substantially identical exhaust mixer housings to create a first converging nozzle and a converging-diverging nozzle arrangement. A second set of nozzle modules is inserted into a second set of identical exhaust mixer housings to create a second different converging and diverging nozzle arrangement.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The first set of nozzle modules is a set of converging nozzles.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The first set of nozzle modules is a set of converging-diverging nozzles.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second converging nozzle and converging-diverging nozzle arrangement have different flow characteristics than the first converging nozzle and converging-diverging nozzle arrangement.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second set of nozzle modules includes a second set of converging-diverging nozzles having a different throat cross-sectional area than the first set of nozzles.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second set of nozzle modules includes a second set of converging nozzles having a different cross-sectional area of converging ends than the first set of nozzles.

An exemplary embodiment of the subject matter described in this disclosure is an engine system having the following features. The intake manifold is configured to receive a combustible mixture configured to be combusted within the combustion chamber. The throttle is upstream of the intake manifold. The throttle is configured to at least partially regulate air flow into the intake manifold. The exhaust manifold is configured to receive combustion products from the combustion chamber. An exhaust gas recirculation mixer system is downstream of the throttle and upstream of the intake manifold. The exhaust gas recirculation mixer includes an exhaust housing having an exhaust gas inlet into an interior of the exhaust housing. The converging nozzle is in the mixer housing and in a flow path from an air inlet of the mixer to an outlet of the mixer. The converging nozzle converges towards the outlet of the mixer. The converging-diverging nozzle is in the mixer housing and includes an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and an interior of the exhaust housing. The first nozzle module is configured to be received in the mixer housing and, when received in the mixer housing, defines at least a portion of a converging nozzle or a converging-diverging nozzle. The second nozzle module is configured to be received in the mixer housing when the first nozzle module is not in the mixer housing. The second nozzle module, when received in the mixer housing, is configured to define at least a portion of a converging nozzle or a converging-diverging nozzle. The second nozzle module has a different flow characteristic than the first nozzle module.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The recirculation mixer includes a first pressure port positioned upstream of the converging nozzle. The first pressure port provides a location to sense a first pressure upstream of the converging nozzle. The second pressure port is positioned at the converging end of the converging nozzle. The second pressure port provides a location to sense a second pressure at the converging end of the converging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The third pressure port is positioned in the throat of the converging-diverging nozzle. The third pressure port provides a location to sense a third pressure within the throat of the converging-diverging nozzle. The fourth pressure port is positioned downstream of the converging-diverging nozzle. The fourth pressure port provides a location to sense a third pressure downstream of the converging-diverging nozzle.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The controller includes one or more processors and a non-transitory computer-readable storage medium coupled to the one or more processors and storing program instructions for execution by the one or more processors. The program instructions instruct one or more processors to perform the following operations. A first pressure differential is determined between a first pressure location positioned upstream of the converging nozzle and a second pressure location positioned at a converging end of the converging nozzle. An air mass flow rate is determined based on the determined first pressure differential. A second pressure differential is determined between a third pressure location positioned in the throat of the converging-diverging nozzle and a fourth pressure location positioned downstream of the converging-diverging nozzle. An air-fuel-exhaust flow rate is determined based on the measured second pressure differential.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The crankcase is within the engine block. A first conduit fluidly connects the crankcase to a point upstream of the throttle valve. A second conduit fluidly connects the crankcase to a point downstream of the throttle valve. The pressure differential across the throttle causes air to flow through the crankcase.

Aspects of the exemplary embodiments that can be combined with the exemplary embodiments individually or in combination include the following. The second conduit is fluidly connected to the exhaust gas recirculation mixer upstream of the converging-diverging nozzle and downstream of the converging nozzle.

The details of one or more implementations of the subject matter are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the subject matter will be apparent from the description and drawings, and from the claims.

Drawings

FIG. 1 is a schematic diagram of an exemplary internal combustion engine system.

FIG. 2 is a side, semi-sectional schematic view of an exemplary Exhaust Gas Recirculation (EGR) mixer.

FIG. 3 is a side, semi-sectional schematic view of an exemplary EGR mixer having a differential pressure sensor and a pressure sensing port.

FIG. 4 is a block diagram of an example controller that may be used with aspects of the present disclosure.

FIG. 5 is a schematic illustration of an exemplary internal combustion engine system having a crankcase ventilation.

FIG. 6A is a side half-sectional view of an interchangeable converging-diverging nozzle module.

FIG. 6B is a side half-sectional view of an interchangeable converging nozzle module.

Fig. 6C is a flow diagram of an exemplary method that may be used with aspects of the present disclosure.

Fig. 7A-7C are side cross-sectional, and perspective views of an exemplary EGR mixer with liquid drain taken along line 7B-7B.

Fig. 8A-8B are side cross-sectional views and cross-sectional views along line 8B-8B of an exemplary EGR mixer with a plug to prevent liquid accumulation.

Like reference numbers and designations in the various drawings indicate like elements.

Detailed Description

EGR can have parasitic effects on the engine system, i.e., it can reduce the effective power output of the engine system because energy is required to move exhaust gas from the exhaust manifold into the intake manifold. This is particularly problematic on supercharged engines where the intake manifold pressure may be higher than the exhaust manifold pressure. Ironically, EGR is most desirable when intake manifold pressure is high, such as when the engine is operating at high loads. In the case of turbocharged engines, increased back pressure in the exhaust manifold may also promote a tendency for knock at high loads.

The concepts herein relate to EGR systems that may be used with internal combustion engines, including supercharged internal combustion engines. A jet pump is added to the engine intake system between the throttle and the intake manifold (but it could alternatively be placed upstream of the throttle). If a compressor is provided in the air intake system, the jet pump may be placed downstream of the compressor (but it may alternatively be placed upstream of the compressor). Air, i.e., the main fluid, flows from the throttle valve toward the intake manifold through the center flow path of the injection pump. In the low pressure receiver region within the jet pump, recirculated exhaust gas is added to the air flow from the exhaust manifold. The lower effective pressure in the receiver allows a pressure differential to develop between the exhaust manifold and the receiver. The reverse bernoulli effect restores pressure by slowing high velocity/low pressure gases, creating a pressure in the intake manifold equal to or higher than the exhaust manifold. Thus, at a system level, the injection pump flows exhaust gas from the exhaust manifold to the intake manifold even when the exhaust manifold is at a lower pressure. Fuel may be added to the air flow upstream of the converging end of the converging nozzle. Turbulence is created as the three streams combine within the jet pump, which results in a well mixed combustible mixture flowing into the manifold.

FIG. 1 illustrates an exemplary engine system 100. The engine system 100 includes an intake manifold 104, the intake manifold 104 configured to receive a combustible mixture to be combusted within a combustion chamber of the engine block 102. That is, the intake manifold is fluidly coupled to an oxygen source and a fuel source. The combustible mixture may include air and any combustible fluid, such as natural gas, atomized gasoline, or diesel. Although the illustrated embodiment includes a four cylinder engine 102, any number of cylinders may be used. Further, although the illustrated embodiment includes a piston engine 102, aspects of the present disclosure may be applied to other types of internal combustion engines, such as rotary engines or gas turbine engines.

A throttle valve 112 is positioned upstream of the intake manifold 104. The throttle valve 112 is configured to regulate airflow from the ambient environment 116 into the intake manifold 104, for example, by varying a cross-sectional area of a flow path through the throttle valve 112. In some embodiments, the throttle valve 112 may comprise a butterfly valve or a disc valve. Reducing the cross-sectional area of the flow path through the throttle valve 112 reduces the amount of air flow through the throttle valve 112 toward the intake manifold 104.

The exhaust manifold 106 is configured to receive combustion products (exhaust gases) from the combustion chambers of the engine block 102. That is, the exhaust manifold is fluidly coupled to the outlets of the combustion chambers. An EGR flow passage 108 or conduit fluidly connects exhaust manifold 106 and intake manifold 104. In the illustrated embodiment, an EGR throttle valve 126 is located in the EGR flow passage 108 between the exhaust manifold 106 and the intake manifold 104 and is used to regulate EGR flow. The EGR throttle valve 126 regulates EGR flow by adjusting the cross-sectional area of the EGR flow path 108 through the EGR throttle valve 126. In some embodiments, the EGR throttle valve 126 may include a butterfly valve, a disc valve, a needle valve, or another valve type.

In the illustrated embodiment, the EGR flow path feeds into an EGR mixer 114 located downstream of the throttle valve 112 and upstream of the intake manifold 104. The EGR mixer 114 is fluidly connected to the throttle valve 112, the intake manifold 104, and the EGR flow path 108 in the engine intake system. The fluid connection may be made by a conduit containing a flow channel allowing fluid flow. In some embodiments, the EGR mixer 114 may be included in a conduit connecting the intake manifold 104 to the throttle valve 112, within the intake manifold 104 itself, within the EGR runner 108, integrated within the throttle valve 112, or integrated within the EGR throttle valve 126. Details regarding an exemplary EGR mixer are described later in this disclosure.

In the illustrated embodiment, the exhaust gas cooler 110 is positioned in the EGR flow passage 108 between the exhaust manifold 106 and the EGR mixer 114. The exhaust gas cooler may be operated to reduce the temperature of the exhaust gas prior to the EGR mixer. The exhaust gas cooler is a heat exchanger, such as an air-to-air exchanger or an air-to-water exchanger.

In some embodiments, the engine system 100 includes a compressor 118 upstream of the throttle valve 112. In an engine having a compressor 118 but no throttle, such as a non-throttled diesel engine, no throttle is required and the mixer may be downstream of the compressor. Compressor 118 may include a centrifugal compressor, a positive displacement compressor, or another type of compressor for increasing the pressure within EGR flow passage 108 during engine operation. In some embodiments, the engine system 100 may include an intercooler 120 configured to cool the compressed air prior to the air entering the manifold. In the illustrated embodiment, the compressor 118 is part of a turbocharger. That is, the turbine 122 is located downstream of the exhaust manifold 106 and rotates as the exhaust gases expand through the turbine 122. The turbine 122 is coupled to the compressor 118, for example, via a shaft, and rotates the compressor 118. While the illustrated embodiment utilizes a turbocharger to increase intake manifold pressure, other methods of compression may be used, such as an electric or engine-driven compressor (e.g., a supercharger). In some embodiments, a separate controller 130 or Engine Control Unit (ECU) is used to control various aspects of system operation. For example, the controller 130 may adjust the air-fuel ratio, spark timing, and EGR flow rate based on current operating conditions.

FIG. 2 is a side, semi-sectional schematic view of the exemplary EGR mixer 114. The EGR mixer 114 is comprised of one or more housings or casings. Openings in the end walls of the housing define the air inlet 204 and outlet 206 of the interior flow passage 222 defined by the housing 224. The internal flow passage 222 directs flow from the air inlet 204 to the outlet 206 to allow flow through the EGR mixer 114. Within the housing 224, the EGR mixer 114 includes a converging nozzle 202 in the flow path from the air inlet 204 of the EGR mixer 114 to the outlet 206 of the EGR mixer 114. The converging nozzle 202 includes a converging portion 203 that converges in a direction of flow toward a converging end 208. That is, the downstream end (outlet) of converging nozzle 202 has a smaller cross-sectional area, i.e., a smaller flow area, than the upstream end (inlet) 226 of converging nozzle 202. The converging nozzle may include a portion that does not converge but remains relatively straight without changing the cross-sectional flow area. These sections may be used to retain converging nozzle 202 within EGR mixer 114. The EGR mixer 114 includes an exhaust gas receiver housing 210, and the housing 210 includes one or more exhaust gas inlets 212, the exhaust gas inlets 212 feeding from the EGR flow passage 108 and fluidly connecting to the EGR flow passage 108 and into an internal receiver cavity 228 of the exhaust housing 210. In the illustrated embodiment, the housing 210 surrounds the converging nozzle 202 such that a portion of the converging nozzle 202 is within the interior receiver cavity 228. The converging nozzle 202 is positioned to form a free jet of gas from the converging end 208 of the converging nozzle 202. Further, the exhaust gas inlet 212 is upstream of the converging end 208 of the converging nozzle 202. While the illustrated embodiment shows the converging nozzle 202 at least partially within the exhaust receiver housing 210, other designs may be used. In some embodiments, the air inlet 204 and the outlet 206 are provided with accessories or fittings to enable connection to the intake manifold 104 of the engine block 102 and/or the EGR mixer 114. In some cases, converging nozzle 202 may be modularly interchangeable with nozzles having different inlet areas 226 and/or converging ends 208, thereby making the system easily adaptable to accommodate a variety of engine sizes. For example, the converging nozzle 202 may be provided with threads or another form of removable attachment to the remainder of the mixer housing 224. Examples of such modularity will be discussed later in this disclosure.

Converging-diverging nozzle 214 is downstream from converging portion 203 of converging nozzle 202 and is fluidly coupled to receive a fluid flow from converging end 208, exhaust inlet 212, and, in some cases, fuel supply 216. In other words, the converging-diverging nozzle 214 may serve as an air-fuel-exhaust inlet for the intake manifold 104. To help promote mixing, the inlet 230 of the converging-diverging nozzle 214 has a larger area than the outlet of the converging nozzle 202. The converging-diverging nozzle includes three sections: an inlet 230, a throat 232, and an outlet 206. The throat 232 is the narrowest point of the converging-diverging nozzle and is located and fluidly connected downstream of the inlet 230 of the converging-diverging nozzle 214. Narrowing the converging-diverging nozzle at throat 232 increases the flow velocity of the fluid stream as it passes through converging-diverging nozzle 214. A converging-diverging nozzle 214 is fluidly connected to and upstream from intake manifold 104. Between the throat 232 and the outlet 206, the cross-section of the flow passage through the converging-diverging nozzle 214 increases. The increase in cross-sectional area slows the flow rate and increases the pressure of the fluid flow. In some cases, the increase in cross-sectional area may be sized to increase the pressure within the EGR mixer 114 such that the pressure drop across the EGR mixer 114 is zero, a nominal value, or small. Converging-diverging nozzle 214 may include threads or another form of removable attachment at inlet 230, outlet 206, or both, to allow converging-diverging nozzle 214 to be mounted and fluidly connected to the remainder of the intake of engine system 100. As with the converging nozzle 202, the converging-diverging nozzle 214 can be modularly interchanged with nozzles 214 having different inlet 230, throat 232, and outlet 206 areas to make the system easily adaptable to a variety of engine sizes.

The illustrated embodiment shows the converging nozzle and the converging-diverging nozzle aligned at the same central axis 220, but in some embodiments, the central axes of the converging nozzle and the converging-diverging nozzle may not be aligned or parallel. For example, spatial constraints may require the EGR mixer to have an angle between the axes of the converging nozzle and the converging-diverging nozzle. In some embodiments, the flow channels may be curved rather than having substantially straight flow channels as shown in FIG. 2.

As shown, the fuel supply 216 includes a fuel supply tube 218 that terminates parallel and centrally within the air flow path. The fuel supply pipe 218 is configured to supply fuel into the air flow path in a direction of flow through the EGR mixer 114, and upstream of the converging portion 203 of the converging nozzle 202. In some embodiments, fuel supply 218 may be a gaseous fuel supply coupled to a source of gaseous fuel. However, the fuel delivered by the fuel supply 218 may include any combustible fluid, such as natural gas, gasoline, or diesel. Although shown as a single tube, the fuel supply tube 218 may be configured in other ways, such as a cross-piece through the flow area of the mixer, as a fuel delivery hole along the perimeter of the flow area, or otherwise. Although the illustrated embodiment shows the fuel supply pipe 218 configured to inject fuel upstream of the converging portion 203 of the converging nozzle 202, fuel may also be added through the fuel supply port 234 upstream of the exhaust inlet 212. That is, fuel may be injected into the EGR flow. Such ports may include gaseous fuel supply ports. In some cases, the fuel may be delivered at a high velocity, up to and including the sonic flow at the fuel supply pipe 218, thereby also creating a fuel/air injection pump that allows the fuel to provide additional power for the primary air to flow into and through the nozzle. In this case, the higher pressure that makes it possible to generate the sonic jet further enhances the mixing of the fuel and air. This reduces the need for a fuel pressure regulator. Furthermore, if the fuel jet becomes cold via the Joule-Thompson effect, it will cool the air/fuel stream, thereby reducing the heat removal requirements of the air path charge air cooler. Alternatively or additionally, fuel may be added upstream of throttle valve 112.

The illustrated embodiment operates as follows. The converging portion 203 of the converging nozzle 202 increases the velocity and decreases the pressure of the gas flow 302 in the EGR mixer 114. In response to (e.g., because of) the pressure drop of the free-jet stream 302 exiting the converging nozzle 202, an exhaust stream 304 is drawn into the EGR mixer 114 through the exhaust inlet 212. The exhaust flow 304 is ultimately directed from the exhaust manifold 106 to a point downstream of the converging portion 203 of the converging nozzle 202. The air flow 302, the exhaust flow 304, and the fuel flow 306 mix to form a combustion mixture 308, and the second converging nozzle 214a is positioned downstream of the converging portion 203 of the converging nozzle 202. Through the diverging nozzle 214b, the pressure of the combustion mixture increases and the velocity of the combustion mixture decreases. Although the second converging nozzle 214a and the diverging nozzle 214b are shown as a single converging-diverging nozzle 214, the second converging nozzle 214a and the diverging nozzle 214b may be separate distinct components.

In the illustrated embodiment, the fuel flow 306 is supplied into the air flow 302, and the fuel supply pipe 218 is parallel and in-line with the center of the air flow passage. The fuel flow is supplied upstream of the converging portion 203 of the converging nozzle 202. In some embodiments, a fuel stream is supplied into the exhaust stream through a fuel supply port. Regardless of the embodiment used, the fuel stream 306 may comprise a gaseous fuel stream. In some embodiments, the fuel flow 306 has an injection velocity that is higher than the velocity of the air flow 302. Such high velocities may facilitate mixing of the air flow 302, the fuel flow 306, and the exhaust flow 304.

In some embodiments, the throat 232 of the converging-diverging nozzle 214 has a cross-sectional flow area that is greater than the cross-sectional flow area of the converging end 208 of the converging nozzle 202. For example, the minimum flow area of the throat 232 of the converging-diverging nozzle 214 may be 1.1-3 times the minimum flow area of the converging end 208 of the converging nozzle 202. Generally, efficient performance is achieved when the throat 232 is sized such that the two fluid streams can pass through the throat 232 at approximately the same velocity. For example, at 25% EGR at 120 ℃, the area of the throat 232 is approximately 1.5 times the flow area of the converging end 208 of the converging nozzle 202.

FIG. 3 is a side, semi-schematic section view of an exemplary EGR mixer 114 having a differential pressure sensor and a pressure sensing port. The first pressure port 352 is positioned upstream of the converging portion 203 of the converging nozzle 202. The first pressure port 352 provides a location to sense pressure upstream of the converging nozzle 202 by allowing fluid communication between the internal flow passage 222 and a first differential pressure sensor 354. The second pressure port 356 is positioned after the converging portion 203 of the converging nozzle 202, such as at the converging end 208. The second pressure port 356 provides a location to sense pressure at the converging end 208 of the converging nozzle 202 by allowing fluid communication between the internal flow passage 222 and the first differential pressure sensor 354. Although shown with a differential sensor, separate, discrete sensors with similar effects may also be used. Alternatively or additionally, virtual sensors may be used instead of discrete sensors. As shown, the second pressure port 356 is integrated into the converging nozzle 202, but a separate, discrete sensing port with similar results may be used.

The third pressure port 358 is positioned in the throat 232 of the converging-diverging nozzle 214. The third pressure port 358 provides a location to sense pressure within the throat 232 of the converging-diverging nozzle 214 by allowing fluid communication between the internal flow passage 222 and the second differential pressure sensor 360. The fourth pressure port 362 is positioned downstream of the throat 232 of the converging-diverging nozzle 214. The fourth pressure port 362 provides a location to sense pressure downstream of the converging-diverging nozzle 214 by allowing fluid communication between the internal flow passage 222 and the second differential pressure sensor 360.

The differential pressure sensed by the first differential pressure sensor 354 may be used to determine a Mass Air Flow (MAF) rate through the EGR mixer 114. The second differential pressure sensed by the second differential pressure sensor 360 may be used to determine an air-fuel-exhaust mass flow rate. The difference between the mass air flow rate and the air-fuel-exhaust flow rate may be used to calculate an EGR mass flow rate. In some cases, such calculations may be performed by controller 130 (FIG. 1). The MAF and EGR flow rates may be used as inputs to a controller to adjust various parameters within the engine system 100. In some cases, the controller 130 is an Engine Control Unit (ECU) that controls some or all aspects of the operation of the engine system 100, such as fuel supply, air, ignition, and/or other engine operating parameters. In some cases, the controller 130 is a control unit separate from the ECU of the engine system. The controller 130 also need not send actuation and/or control signals to the engine system 100, but may instead provide information such as MAF and EGR flow rates to the ECU for use by the ECU in controlling the engine system 100.

Fig. 4 is a block diagram of an example controller 130 that may be used with aspects of the present disclosure. The controller 130 may, among other things, monitor parameters of the system and send signals to actuate and/or adjust various operating parameters of the system. As shown in fig. 4, the controller 130 may include one or more processors 450 and a non-transitory storage medium (e.g., memory 452) containing instructions that cause the processors 450 to perform the operations described herein. The processor 450 is coupled to an input/output (I/O) interface 454 for sending and receiving communications with components in the system, including, for example, the first differential pressure sensor 354 and the second differential pressure sensor 360. In some cases, the controller 130 may also communicate with and send actuation and/or control signals to one or more of the various system components of the engine system 100, including the throttle valve 112 and the EGR throttle valve 126, as well as other sensors disposed in the engine system 100 (e.g., pressure sensors, temperature sensors, knock sensors, and other types of sensors).

FIG. 5 is a schematic illustration of an exemplary internal combustion engine system having a crankcase ventilation. As shown, the engine system 100 includes a first crankcase ventilation conduit 402 fluidly connected to an intake conduit 502 upstream of the throttle valve 112. The first crankcase ventilation conduit 402 draws air from the intake conduit 502 toward the engine block 102. In particular, a first crankcase ventilation conduit 402 directs air through the crankcase of the engine block 102. Although shown as being directly connected to the engine block 102, the first crankcase ventilation conduit 402 may be attached to any portion of the engine so long as it is fluidly connected to the crankcase. In some embodiments, an intake check valve 404 may be included in the first crankcase ventilation conduit 402 to ensure that there is no backflow. Check valve 404 may be any check valve having a low pressure drop suitable for the service, such as a ball-type check valve. Within the engine block 102 is a crankcase flow path 406 through the crankcase. In some configurations, the crankcase may be separate from the engine block. In this configuration, the crankcase flow path 406 will flow through a separate crankcase. A second crankcase ventilation conduit 408 fluidly connects the crankcase to a point downstream of the throttle valve 112. Although shown as being directly connected to the engine block 102, the second crankcase ventilation conduit 408 may be attached to any portion of the engine so long as it is fluidly connected to the crankcase. The pressure drop across the throttle valve 112 causes a pressure differential to drive the flow of air through the first crankcase ventilation conduit 402, the crankcase flow path 406, and the second crankcase ventilation conduit 408. In some embodiments, a second check valve 410 may be included in the second crankcase ventilation conduit 408 to ensure that there is no backflow. The check valve may be any check valve with a low pressure drop suitable for the service, such as a ball-type check valve. In some embodiments, a restrictor (choke) 412 may be positioned within the first crankcase ventilation conduit 402 or the second crankcase ventilation conduit 408 to regulate the air flow rate through the crankcase. The restriction 412 may include a restriction orifice, a regulator valve, or another device for regulating the flow through the conduit 401. The restrictor 412 regulates the flow rate by controlling the cross-sectional flow area of the second crankcase ventilation conduit 408. The cross-sectional flow area is inversely proportional to the pressure drop across the restrictor 412 and, in turn, controls the flow rate through the restrictor 412.

As shown, the second conduit 408 is fluidly connected to the EGR mixer 114. To help facilitate flow, second conduit 408 may feed into the EGR mixer (see in fig. 2 and/or 3) upstream of converging-diverging nozzle 214 and downstream of the converging nozzle, which is the lowest pressure system of EGR mixer 114. For example, a second conduit may feed into the exhaust housing 210. The pressure drop creates a significant pressure differential to drive flow through the crankcase. In some embodiments, the second conduit 408 may be inserted into the air flow upstream of the EGR mixer 114. In such embodiments, the EGR mixer 114 is located in-line within the intake conduit 502 (fig. 5) between the throttle valve 112 and the intake manifold. In some embodiments, the second crankcase ventilation conduit 408 may be connected to the intake conduit 502 between the throttle valve 112 and the EGR mixer 114. In such embodiments, the pressure differential across the throttle valve 112 is sufficient to drive flow through the crankcase. Directing crankcase ventilation gas between the throttle valve 112 and the EGR mixing section allows the crankcase ventilation gas to mix with the EGR.

FIG. 6A is a side semi-sectional view of an exemplary converging-diverging nozzle module that may be used to construct EGR mixer 114 in accordance with FIG. 3. For ease of construction, the EGR mixer 114 may be constructed using common external components (e.g., the mixer housing 224 of fig. 3) and various nozzle modules that may be inserted into the mixer housing 224 according to the flow requirements of the EGR mixer 114. For example, FIG. 6A shows a converging-diverging nozzle 602 that may be designed for larger, higher load engines, but that other nozzle profiles may be inserted for applications using smaller or lower load engines. The second converging-diverging nozzle 604 or the third converging nozzle 606 reduces the cross-sectional flow area through the throat 232 of the converging-diverging nozzle section.

In some embodiments, multiple converging-diverging nozzles may be cast or molded with the same outer mold, while the inner profile may be cast or molded with interchangeable inner molds configured to mate with the outer mold. In some embodiments, the various converging-diverging nozzle modules are manufactured with a common inner and outer mold and then have a specific profile machined along the interior of the converging-diverging nozzle module. The interchangeable converging-diverging nozzles (602, 604, and 606) may be attached to the mixer housing 224 in a variety of ways, for example, by a threaded connection, a bayonet connection, or a press-fit connection. In some embodiments, the converging-diverging nozzle is held in place within the assembly by mating components. For example, the converging-diverging nozzle may be compressed between a shoulder of the housing and a mating component, such as an elbow in the fluid conduit.

FIG. 6B is a side half-sectional view of an interchangeable converging nozzle. For ease of construction, the EGR mixer 114 may be constructed using a common outer component (e.g., mixer housing 224) and interchangeable converging nozzles that may be inserted into the common outer component depending on the size of the engine within the engine system and the desired EGR flow rate. For example, first converging nozzle 608 may be designed for use with larger, higher load engines, and second converging nozzle 610 may be inserted for applications using smaller or lower load engines. As shown, the converging end of the second converging nozzle 610 through the second converging nozzle 610 has a reduced cross-sectional flow area as compared to the first converging nozzle 608.

In some embodiments, multiple converging nozzles may be cast or molded with the same outer mold, while the inner profile may be cast or molded with interchangeable inner molds configured to mate with the outer mold. In some embodiments, the various converging nozzle modules are manufactured with a common inner and outer mold and then have a specific profile machined along the interior of the converging nozzle module. The various converging nozzle modules (608 and 610) may be attached to the mixer housing 224 in a variety of ways, for example, by a threaded connection, a bayonet connection, or a press-fit connection. In some embodiments, the converging nozzle is held in place by the fuel tube. That is, the fuel tubes act as retaining pins that provide an interference barrier to prevent movement between the converging nozzle and the housing.

Although shown and described as using two modules, a converging nozzle module and a converging-diverging nozzle, more or fewer modules may be used without departing from this disclosure. For example, a converging-diverging nozzle may be constructed from separate converging and diverging nozzle modules. Alternatively or additionally, all or a portion of the nozzles may be attached to the housing 210 as a single piece or multiple pieces. For example, the converging nozzle 202 and the housing 210 may be constructed as a single casting configured to receive separate converging-diverging nozzle modules (602, 604, or 606). In another example, the converging-diverging nozzle 214 and the housing 210 may be constructed as a single casting configured to receive separate converging nozzle modules (608 or 610).

Fig. 6C is a flow diagram of an exemplary method 650 that may be used with aspects of the present disclosure. In particular, the method 650 may be used during the manufacture of the EGR mixer 114. At 652, a substantially identical exhaust mixer housing is received. At 654, a first set of nozzles is inserted into a first set of substantially identical exhaust mixer housings to produce a first converging nozzle and a converging-diverging nozzle arrangement. In some cases, the first set of nozzles is a set of converging nozzles. In some cases, the first set of nozzles is a set of converging-diverging nozzles.

At 656, a second set of nozzles is inserted into the second set of exhaust mixer housings to create a second converging nozzle and converging-diverging nozzle arrangement having different flow characteristics than the first converging nozzle and converging-diverging nozzle arrangement. In some cases, the second set of nozzles are a second set of converging-diverging nozzles having a different throat cross-sectional area than the first set of nozzles. In some cases, the second set of nozzles is a second set of converging nozzles having a different cross-sectional area of converging ends than the first set of nozzles.

Fig. 7A-7C are side cross-sectional, and perspective views of the exemplary EGR mixer 114 with liquid drain passage 702, taken along line 7B-7B. As the gas flows through the converging portion 203 of the converging nozzle 202 and the subsequent throat 232 of the converging-diverging nozzle 214, liquid, such as water, often drips from the gas stream in response to the rapid decrease in pressure and/or the rapid cooling of EGR. Liquid may accumulate within the EGR mixer to the point where liquid entrainment and liquid slugging (slugging) may occur. That is, a large amount of liquid may be carried into the intake manifold and subsequently into the combustion chambers of the internal combustion engine.

In some embodiments, discharge channel 702 may be included in converging-diverging nozzle 214. The drain passage 702 allows liquid to trickle through the EGR mixer 114 at a rate low enough to prevent liquid slugging events that can cause damage to the internal combustion engine. Discharge channel 702 is located on the bottom side of converging-diverging nozzle 214. The exhaust passage 702 begins outside of the converging-diverging nozzle, such as with the exhaust housing 210, and ends at the outlet 206 of the EGR mixer 114. The exhaust housing 210 surrounds the converging-diverging nozzle 214 and defines a chamber below the nozzle inlet. During operation, liquid accumulated within the exhaust housing 210 may rise above the inlet of the converging-diverging nozzle and be drawn into the main flow through the mixer. The passages are sized based on expected water droplets and expected pressure drop within the EGR mixer to maintain the liquid level below the inlet of the converging-diverging nozzle without significantly changing the flow characteristics through the EGR mixer 114.

The exhaust passage is also arranged to adjust a maximum height of liquid accumulation within the EGR. For example, the maximum liquid level in the EGR mixer without the exhaust passage 702 is at a first level 704. The level has a sufficient amount of liquid to cause a liquid slugging event that damages the engine. For the drain channel, the maximum liquid level is at a second level 706. In this case, the liquid is continually flowed back into the air stream at a rate low enough to evaporate before entering the combustion chamber, thereby minimizing the risk of a liquid slugging event that damages the engine. In some embodiments, the vent channel 702 is also of sufficient size to prevent particles from clogging the channel.

Alternatively or additionally, a plug may be installed to prevent a liquid slugging event. FIGS. 8A-8B are a side cross-sectional view and a cross-sectional view along line 8B-8B of an exemplary exhaust gas recirculation mixer having a plug to prevent liquid accumulation. The plug 802 occupies space that may retain enough water to cause a liquid slugging event. Plug 802 changes the cross-sectional flow area of internal receiver cavity 228 such that it is non-circular. That is, the inner contour of the inner receiver cavity 228 has a larger radius along an upper portion of the inner contour than a lower portion of the inner contour. Since the plug 802 occupies a volume that may allow for such accumulation, liquid dripping from the air stream flows immediately with the primary air stream at a sufficiently low velocity to vaporize prior to entering the combustion chamber, thereby minimizing the risk of a liquid slugging event.

While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations of particular subject matter. Certain features that are described in this disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, in the above-described embodiments, the separation of various system components should not be understood as requiring such separation in all embodiments, and it should be understood that the components and systems described may generally be integrated together in a single product or packaged into multiple products.

Various embodiments of the present subject matter have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other embodiments are within the scope of the following claims and may be alternatively defined in accordance with the following aspects.

1. An exhaust gas recirculation mixer system, comprising:

an exhaust housing including an exhaust inlet into an interior of the exhaust housing;

a mixer housing;

a converging nozzle in the mixer housing and in a flow path from an air inlet of the mixer to an outlet of the mixer, the converging nozzle converging toward the outlet of the mixer;

a converging-diverging nozzle in the mixer housing and including an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and an exhaust housing interior;

a first nozzle module configured to be received in the mixer housing and, when received in the mixer housing, define at least a portion of a converging nozzle or a converging-diverging nozzle; and a second nozzle module configured to be received in the mixer housing when the first nozzle module is not in the mixer housing, the second nozzle module configured to define at least a portion of a converging or converging-diverging nozzle when received in the mixer housing, and the second nozzle module having different flow characteristics than the first nozzle module.

2. The exhaust gas recirculation mixer system of aspect 1, wherein the first nozzle module defines a portion of a converging nozzle.

3. The exhaust gas recirculation mixer system of any of the preceding aspects, wherein the second nozzle module defines a portion of a converging-diverging nozzle.

4. The exhaust gas recirculation mixer system of any of the preceding aspects, wherein an inlet of the converging-diverging nozzle is positioned to receive the air-exhaust-fuel mixture.

5. The exhaust gas recirculation mixer system of any of the preceding aspects, further comprising:

a first pressure port positioned at the converging end of the converging nozzle, the first pressure port providing a location to sense a first pressure at the converging end of the converging nozzle.

6. The exhaust gas recirculation mixer system of aspect 5, further comprising:

a second pressure port upstream of the converging portion of the converging nozzle, the second pressure port providing a location to sense a second pressure upstream of the converging nozzle.

7. The exhaust gas recirculation mixer system of any of aspects 5-6, further comprising:

a third pressure port positioned in the throat of the converging-diverging nozzle, the third pressure port providing a location to sense a third pressure within the throat of the converging-diverging nozzle; and

a fourth pressure port positioned downstream of the diverging portion of the converging-diverging nozzle, the fourth pressure port providing a location to sense a third pressure downstream of the converging-diverging nozzle.

8. The exhaust gas recirculation mixer system of any of the preceding aspects, further comprising:

a liquid passage defined by the converging-diverging nozzle, the liquid passage having an inlet positioned between the converging nozzle and the converging-diverging nozzle, the liquid passage positioned and sized to direct and regulate liquid drippings toward the outlet of the exhaust gas recirculation mixer.

9. The exhaust gas recirculation mixer system of any one of the preceding aspects, wherein an inner surface of the inner receiver cavity is non-circular having a larger radius along an upper portion of the inner receiver cavity than a lower portion of the inner receiver cavity.

10. The exhaust gas recirculation mixer system of any of the preceding aspects, wherein a throat of the converging-diverging nozzle has a larger cross-sectional area than a converging end of the converging nozzle.

11. The exhaust gas recirculation mixer system of any of the preceding aspects, wherein a cross-sectional area of a throat of the converging-diverging nozzle is 1.1-3 times greater than a cross-sectional area of a converging end of the converging nozzle.

12. A method, comprising:

receiving a plurality of identical exhaust mixer housings;

inserting a first set of nozzle modules into a first set of a plurality of substantially identical exhaust mixer housings to create a first converging nozzle and a converging-diverging nozzle arrangement; and

inserting a second set of nozzle modules into a second plurality of identical exhaust mixer housings to create a second different converging and diverging nozzle arrangement.

13. The method of aspect 12, wherein the first set of nozzle modules is a set of converging nozzles.

14. The method of aspect 12, wherein the first set of nozzle modules is a set of converging-diverging nozzles.

15. The method of aspect 12, wherein the second converging nozzle and converging-diverging nozzle arrangement have different flow characteristics than the first converging nozzle and converging-diverging nozzle arrangement.

16. The method of aspect 15, wherein the second set of nozzle modules comprises a second set of converging-diverging nozzles having a different throat cross-sectional area than the first set of nozzles.

17. The method of aspect 15, wherein the second set of nozzle modules comprises a second set of converging-diverging nozzles having a different converging end cross-sectional area than the first set of nozzles.

18. An engine system, comprising:

an intake manifold configured to receive a combustible mixture configured to be combusted within the combustion chamber;

a throttle upstream of the intake manifold, the throttle configured to at least partially regulate air flow into the intake manifold;

an exhaust manifold configured to receive combustion products from the combustion chamber; and

an exhaust gas recirculation mixer system downstream of the throttle valve and upstream of the intake manifold, the exhaust gas recirculation mixer comprising:

an exhaust housing including an exhaust inlet into an interior of the exhaust housing;

a mixer housing;

a converging nozzle in the mixer housing and in a flow path from an air inlet of the mixer to an outlet of the mixer, the converging nozzle converging toward the outlet of the mixer;

a converging-diverging nozzle in the mixer housing and including an air-exhaust inlet in fluid communication to receive a fluid flow from the converging nozzle and an exhaust housing interior;

a first nozzle module configured to be received in the mixer housing and, when received in the mixer housing, define at least a portion of a converging nozzle or a converging-diverging nozzle; and

a second nozzle module configured to be received in the mixer housing when the first nozzle module is not in the mixer housing, the second nozzle module configured to define at least a portion of a converging or converging-diverging nozzle when received in the mixer housing, and the second nozzle module having different flow characteristics than the first nozzle module.

19. The engine system of aspect 18, wherein the recirculation mixer comprises:

a first pressure port positioned upstream of the converging nozzle, the first pressure port providing a location to sense a first pressure upstream of the converging nozzle; and

a second pressure port positioned at the converging end of the converging nozzle, the second pressure port providing a location to sense a second pressure at the converging end of the converging nozzle.

20. The engine system of aspect 19, wherein the recirculation mixer comprises:

a third pressure port positioned in the throat of the converging-diverging nozzle, the third pressure port providing a location to sense a third pressure within the throat of the converging-diverging nozzle; and

a fourth pressure port positioned downstream of the converging-diverging nozzle, the fourth pressure port providing a location to sense a third pressure downstream of the converging-diverging nozzle.

21. The engine system of aspect 20, further comprising a controller comprising:

one or more processors; and

a non-transitory computer readable storage medium coupled to the one or more processors and storing program instructions for execution by the one or more processors to instruct the one or more processors to:

determining a first pressure differential between a first pressure location positioned upstream of the converging nozzle and a second pressure location positioned at a converging end of the converging nozzle;

determining an air mass flow rate based on the determined first pressure differential;

determining a second pressure differential between a third pressure location positioned in the throat of the converging-diverging nozzle and a fourth pressure location positioned downstream of the converging-diverging nozzle; and is

An air-fuel-exhaust flow rate is determined based on the measured second pressure differential.

22. The engine system of any of aspects 18-21, further comprising:

a crankcase in the engine block;

a first conduit fluidly connecting the crankcase to a point upstream of the throttle valve; and

a second conduit fluidly connecting the crankcase to a point downstream of the throttle, a pressure differential across the throttle causing air to flow through the crankcase.

23. The engine system of aspect 22, wherein the second conduit is fluidly connected to the exhaust gas recirculation mixer upstream of the converging-diverging nozzle and downstream of the converging nozzle.