阅读说明：本技术 一种egr发动机及其控制方法 (EGR engine and control method thereof ) 是由 张盼望 熊锐 张中威 纪佳圳 李沛焕 于 2019-08-21 设计创作，主要内容包括：一种EGR发动机,包括进气管路、回收管路、排气管路和发动机本体；进气管路与发动机本体的进气口相连通,排气管路与发动机本体的排气口相连通；进气管路上沿进气方向依次设有电子混合阀、压气机、中冷器和电子节气门,排气管路上设有涡轮增压器；回收管路一端与排气管路相连通且位于涡轮增压器的后侧,回收管路另一端与进气管路相连通且位于电子混合阀和压气机之间,回收管路上设有EGR阀和EGR冷却器,进气管路上在压气机的两端之间并联有电子泄气阀。本发明使流过EGR阀的流量正常流通并得到精确控制,同时可以减小回流气体对电子节气门和EGR阀的冲击,起到保护的作用。(An EGR engine comprises an air inlet pipeline, a recovery pipeline, an exhaust pipeline and an engine body; the air inlet pipeline is communicated with an air inlet of the engine body, and the exhaust pipeline is communicated with an exhaust port of the engine body; an electronic mixing valve, a gas compressor, an intercooler and an electronic throttle valve are sequentially arranged on the gas inlet pipeline along the gas inlet direction, and a turbocharger is arranged on the gas outlet pipeline; one end of the recovery pipeline is communicated with the exhaust pipeline and is positioned at the rear side of the turbocharger, the other end of the recovery pipeline is communicated with the air inlet pipeline and is positioned between the electronic mixing valve and the air compressor, the EGR valve and the EGR cooler are arranged on the recovery pipeline, and the electronic air release valve is connected between the two ends of the air compressor in parallel on the air inlet pipeline. The invention enables the flow passing through the EGR valve to normally circulate and be accurately controlled, and simultaneously can reduce the impact of the backflow gas on the electronic throttle valve and the EGR valve, thereby playing the role of protection.)

1. An EGR engine characterized by: the device comprises an air inlet pipeline, a recovery pipeline, an exhaust pipeline and an engine body; the air inlet pipeline is communicated with an air inlet of the engine body, and the exhaust pipeline is communicated with an exhaust port of the engine body; an electronic mixing valve, a gas compressor, an intercooler and an electronic throttle valve are sequentially arranged on the gas inlet pipeline along the gas inlet direction, and a turbocharger is arranged on the gas outlet pipeline; one end of the recovery pipeline is communicated with the exhaust pipeline and is positioned at the rear side of the turbocharger, the other end of the recovery pipeline is communicated with the air inlet pipeline and is positioned between the electronic mixing valve and the air compressor, the EGR valve and the EGR cooler are arranged on the recovery pipeline, and the electronic air release valve is connected between the two ends of the air compressor in parallel on the air inlet pipeline.

2. The EGR engine of claim 1 wherein: the electronic mixing valve and the electronic air release valve are electrically connected with the controller, and the controller controls the electronic mixing valve and the electronic air release valve to act according to the working condition of the engine.

3. The EGR engine of claim 1 wherein: and a catalyst is arranged on the exhaust pipeline, and one end of the recovery pipeline is positioned between the turbocharger and the catalyst.

4. The EGR engine of claim 3 wherein: the catalyst includes a front catalyst and a rear catalyst.

5. A control method of an EGR engine according to any one of claims 1 to 4, characterized by comprising the steps of:

when the engine runs under the working conditions of medium and small loads, the electronic mixing valve is controlled to be closed for a certain opening degree, and when the engine runs under other working conditions, the electronic mixing valve is in a normally open state;

when the engine runs under a large-load working condition, the electronic air release valve is controlled to be opened to a certain opening and closing degree, and when the engine runs under other working conditions, the electronic air release valve is in a normally closed state.

6. The control method according to claim 5, characterized in that:

when the opening degree of the electronic throttle valve is less than or equal to 75%, the engine is under the working conditions of medium and small loads; and when the opening of the electronic throttle valve is larger than 75%, the engine is under a large-load working condition.

Technical Field

The invention relates to the technical field of engines, in particular to an EGR engine and a control method thereof.

Background

Energy-saving law and regulation of all countries in the world and automobileThe emission requirement is becoming more and more strict, and energy conservation and emission reduction become the main development direction of modern automobile technology. The introduction of EGR (exhaust Gas recirculation) technology can effectively reduce oil consumption, reduce pollutant emission, reduce oxygen concentration and combustion temperature, and inhibit the generation of nitrogen oxides, and is an effective means for improving the emission of automobile exhaust. The EGR technique can suppress occurrence of knocking for the following reasons: on the one hand, CO in the exhaust gas₂And H₂O has higher specific heat ratio, can absorb a large amount of heat in the compression and combustion processes, and reduces the temperature in the cylinder, thereby reducing the spontaneous combustion tendency of the tail end mixed gas; on the other hand, the EGR dilutes combustible mixture gas, reduces collision probability of fuel molecules and oxygen molecules, and reduces reaction rate of the tail end mixture gas before flame. Suitable exhaust gas recirculation can reduce the fuel consumption of gasoline engines, but the introduction of exhaust gas is prone to misfire at low loads and can lead to insufficient power at full load, so the main field of application of exhaust gas recirculation technology is in medium and low speed engines.

The existing EGR engine technology mainly has the following defects:

under the condition of low speed and large load, the high-pressure EGR can meet the condition that the inlet pressure is higher than the exhaust pressure, the pressure difference between the upstream and the downstream of the EGR valve is basically zero, the EGR valve does not work, and a pressure regulating valve can be added into an air inlet pipe or an exhaust pipe or a variable-section turbocharger is used for recovering the positive pressure difference between two ends of the EGR valve. Under the conditions of medium and large loads, the pressure difference between the upstream and the downstream of the EGR is small, and the problem of slow response of an EGR signal is brought. When a supercharged gasoline engine is under a large-load working condition and a driver looses an accelerator pedal, the gas backflow impacts a throttle valve and an EGR valve, and the throttle valve and the EGR valve are damaged under the long-time condition. Under the working condition that the engine is under the medium load, the pressure difference between the upstream and the downstream of the EGR valve is small, the flow at the EGR valve is influenced, and the response of gas entering an air inlet manifold is slow.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an EGR engine, which can improve the condition of pressure difference at two ends of an EGR valve, ensure that the flow passing through the EGR valve normally circulates and is accurately controlled, and simultaneously reduce the impact of backflow gas on a throttle valve and the EGR valve to play a role in protection.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an EGR engine comprises an air inlet pipeline, a recovery pipeline, an exhaust pipeline and an engine body; the air inlet pipeline is communicated with an air inlet of the engine body, and the exhaust pipeline is communicated with an exhaust port of the engine body; an electronic mixing valve, a gas compressor, an intercooler and an electronic throttle valve are sequentially arranged on the gas inlet pipeline along the gas inlet direction, and a turbocharger is arranged on the gas outlet pipeline; one end of the recovery pipeline is communicated with the exhaust pipeline and is positioned at the rear side of the turbocharger, the other end of the recovery pipeline is communicated with the air inlet pipeline and is positioned between the electronic mixing valve and the air compressor, the EGR valve and the EGR cooler are arranged on the recovery pipeline, and the electronic air release valve is connected between the two ends of the air compressor in parallel on the air inlet pipeline.

When the engine runs under the working conditions of medium and small loads, the electronic mixing valve receives information of the engine controller, closes a certain opening degree according to the result of the algorithm, and creates pressure difference for the upstream and downstream of the EGR valve after closing the certain opening degree, so that the waste gas smoothly flows into the air inlet pipeline, and when the electronic mixing valve is in a normally open state under other working conditions; when the engine runs under a high-load working condition, the engine controller controls the electronic air release valve to open a certain opening degree, so that pressurized gas plays a role in backflow near the air compressor, part of gas flows back near the air compressor, most of gas flows into the air inlet pipeline, the opening of the electronic air release valve creates pressure difference for the upstream and the downstream of the EGR valve, waste gas smoothly flows into the air inlet pipeline, and the electronic air release valve plays a role in bypass under other working conditions.

In conclusion, when the engine runs under the working conditions of medium and small loads, the electronic mixing valve closes a certain opening degree according to the result of the algorithm, and pressure difference is generated between the upstream and the downstream of the EGR valve after the certain opening degree is closed, so that the exhaust gas smoothly flows into the air inlet pipeline; when the engine runs under a high-load working condition, the engine controller controls the electronic air release valve to open a certain opening degree, so that pressurized gas plays a role in backflow near the gas compressor, part of gas flows back near the gas compressor, most of gas flows into the gas inlet pipeline, and the opening of the electronic air release valve creates pressure difference between the upstream and the downstream of the EGR valve, so that waste gas smoothly flows into the gas inlet pipeline; therefore, the flow passing through the EGR valve can normally circulate and be accurately controlled, and meanwhile, the impact of the backflow gas on the electronic throttle valve and the EGR valve can be reduced, and the effect of protection is achieved.

The electronic mixing valve and the electronic air release valve are electrically connected with the controller, and the controller controls the electronic mixing valve and the electronic air release valve to act according to the working condition of the engine.

As an improvement of the invention, a catalyst is arranged on the exhaust pipeline, and one end of the recovery pipeline is positioned between the turbocharger and the catalyst.

Further, the catalyst includes a front catalyst and a rear catalyst.

The invention also provides an EGR engine control method.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an EGR engine control method comprising the steps of:

when the engine runs under the working conditions of medium and small loads, the electronic mixing valve is controlled to be closed for a certain opening degree, and when the engine runs under other working conditions, the electronic mixing valve is in a normally open state;

when the engine runs under a large-load working condition, the electronic air release valve is controlled to be opened to a certain opening and closing degree, and when the engine runs under other working conditions, the electronic air release valve is in a normally closed state.

Further, when the opening of the electronic throttle valve is less than or equal to 75%, the engine is under the working conditions of medium and small loads; and when the opening of the electronic throttle valve is larger than 75%, the engine is under a large-load working condition.

Compared with the prior art, the invention has the following advantages:

the invention enables the flow passing through the EGR valve to normally circulate and be accurately controlled, and simultaneously can reduce the impact of the backflow gas on the electronic throttle valve and the EGR valve, thereby playing the role of protection.

Drawings

Fig. 1 is a schematic view of an EGR engine according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.