阅读说明：本技术 一种egr率的计算方法、装置、车载终端及储存介质 (EGR rate calculation method and device, vehicle-mounted terminal and storage medium ) 是由 郑良辰 钱鹏飞 刘义强 金昶明 于 2020-02-20 设计创作，主要内容包括：本发明公开了一种EGR率的计算方法、装置、车载终端及储存介质,所述方法包括：获取当前周期通过节气门、碳罐和曲轴通风箱进入进气歧管气体流量；根据通过节气门气体流量、碳罐进入进气歧管气体流量和曲轴通风箱进入进气歧管气体流量,获取通过节气门气体的EGR率、碳罐进入进气歧管气体的EGR率和曲轴通风箱进入进气歧管气体的EGR率；获取上一周期混合腔EGR率和当前周期获取混合腔EGR率的计算步长；根据通过节气门气体的EGR率、碳罐进入进气歧管气体的EGR率、曲轴通风箱进入进气歧管气体的EGR率、上一周期混合腔EGR率和计算步长,获取当前周期混合腔EGR率,能够快速得到准确的EGR率,避免预测的失效。(The invention discloses a method and a device for calculating an EGR (exhaust gas recirculation) rate, a vehicle-mounted terminal and a storage medium, wherein the method comprises the following steps: acquiring the gas flow entering an intake manifold through a throttle valve, a carbon tank and a crankshaft ventilation box in the current period; according to the gas flow passing through the throttle valve, the gas flow entering the intake manifold from the carbon tank and the gas flow entering the intake manifold from the crankshaft ventilation box, the EGR rate of the gas passing through the throttle valve, the EGR rate of the gas entering the intake manifold from the carbon tank and the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box are obtained; acquiring the EGR rate of the mixing cavity in the previous period and the calculation step length of the EGR rate of the mixing cavity in the current period; according to the EGR rate of the gas passing through the throttle valve, the EGR rate of the gas entering the intake manifold from the carbon tank, the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box, the EGR rate of the mixing cavity in the previous period and the calculation step length, the EGR rate of the mixing cavity in the current period is obtained, the accurate EGR rate can be obtained quickly, and the failure of prediction is avoided.)

1. A method of calculating an EGR rate, comprising the steps of:

acquiring the gas flow entering an intake manifold through a throttle valve, the gas flow entering the intake manifold through a carbon tank and the gas flow entering the intake manifold through a crankshaft ventilation box in the current period, wherein the gas flow comprises the exhaust gas flow and the air flow;

according to the gas flow passing through the throttle valve, the gas flow entering the intake manifold from the carbon tank and the gas flow entering the intake manifold from the crankshaft ventilation box, the EGR rate of the gas passing through the throttle valve, the EGR rate of the gas entering the intake manifold from the carbon tank and the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box are obtained;

acquiring the EGR rate of the mixing cavity in the previous period and the calculation step length of the EGR rate of the mixing cavity in the current period;

and acquiring the calculation step length of the EGR rate of the mixing cavity according to the EGR rate of the throttle gas, the EGR rate of the gas entering the intake manifold from the carbon tank, the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box, the EGR rate of the mixing cavity in the previous period and the current period, and acquiring the EGR rate of the mixing cavity in the current period.

2. The method of calculating the EGR rate of claim 1, wherein the obtaining the calculated step size of the last cycle of the mixing chamber EGR rate and the obtaining of the mixing chamber EGR rate for the current cycle comprises:

acquiring the EGR rate of the mixing cavity in the previous period, the total mass of gas in the instantaneous mixing cavity and the flow rate of gas flowing through the instantaneous mixing cavity;

acquiring the gas outflow time of the mixing chamber in the current period according to the total mass of the gas in the instantaneous mixing chamber and the flow rate of the gas flowing through the instantaneous mixing chamber;

judging whether the gas outflow time of the mixing cavity in the current period is greater than the preset time or not;

if so, taking the preset time as the current period to obtain the calculation step length of the EGR rate of the mixing cavity, and if not, taking the gas outflow time of the mixing cavity in the current period as the current period to obtain the calculation step length of the EGR rate of the mixing cavity.

3. The method of calculating an EGR rate according to claim 1, wherein the obtaining a calculation step of the mixture chamber EGR rate from the EGR rate through the throttle gas, the EGR rate through the canister into the intake manifold, the EGR rate through the crankcase into the intake manifold, the EGR rate through the mixing chamber in the previous cycle, and the current cycle, the obtaining the mixture chamber EGR rate in the current cycle includes:

obtaining the EGR rate of the mixing cavity in the current period according to the formula (1):

y_(i+1)＝y_(i)+h*(b₁*K₁+b₂*K₂+b₃*K₃+b₄*K₄) (1)，

wherein: y is_(i)For the last cycle mixing chamber EGR rate, y_(i+1)Mixing chamber EGR rate for the current cycle, b₁、b₂、b₃And b₄Is a predetermined coefficient, K₁、K₂、K₃And K₄And h is a calculation step length for acquiring the EGR rate of the mixing cavity in the current period.

4. The method of calculating the EGR rate according to claim 3, characterized in that K is₁Obtained by the formula (2), said K₂Obtained by the formula (3), said K₃Obtained by the formula (4) and said K₄Obtained by equation (5):

wherein: a is the gas flow passing through the throttle valve, B is the gas flow entering the intake manifold from the carbon tank, C is the gas flow entering the intake manifold from the crankshaft ventilation box, S is the total gas amount in the intake manifold in the current period, A_(i+1)To pass the EGR rate of the throttle gas, B_(i+1)EGR rate and C for canister intake manifold gas_(i+1)The EGR rate of the crankcase ventilation gases entering the intake manifold.

5. An apparatus for calculating an EGR rate, the apparatus comprising:

the device comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the gas flow entering an intake manifold through a throttle valve, a carbon tank and a crankshaft ventilation box in the current period, and the gas flow comprises the exhaust gas flow and the air flow;

the first calculation module is used for acquiring the EGR rate of gas passing through the throttle valve, the EGR rate of gas entering the intake manifold from the carbon tank and the EGR rate of gas entering the intake manifold from the crankshaft ventilation box according to the gas flow passing through the throttle valve, the gas flow entering the intake manifold from the carbon tank and the gas flow entering the intake manifold from the crankshaft ventilation box;

the second acquisition module is used for acquiring the EGR rate of the mixing cavity in the previous period and the calculation step length of the EGR rate of the mixing cavity acquired in the current period;

and the second calculation module is used for acquiring the calculation step length of the EGR rate of the mixing cavity according to the EGR rate of the throttle gas, the EGR rate of the gas entering the intake manifold from the carbon tank, the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box, the EGR rate of the mixing cavity in the previous period and the current period, and acquiring the EGR rate of the mixing cavity in the current period.

6. The apparatus for calculating the EGR rate according to claim 5, wherein the second obtaining module includes:

the first acquisition unit is used for acquiring the EGR rate of the mixing cavity in the previous period;

the second acquisition unit is used for acquiring the total mass of the gas in the instantaneous mixing cavity and the flow rate of the gas flowing through the instantaneous mixing cavity;

and the judging unit is used for judging whether the gas outflow time of the mixing cavity in the current period is greater than the preset time, if so, taking the preset time as the calculation step length of the EGR rate of the mixing cavity in the current period, and if not, taking the gas outflow time of the mixing cavity in the current period as the calculation step length of the EGR rate of the mixing cavity in the current period.

7. The apparatus for calculating the EGR rate according to claim 5, wherein the second calculating module includes:

a first calculating unit, configured to obtain the EGR rate of the mixing chamber in the current period according to formula (1), where formula (1) is:

y_(i+1)＝y_(i)+h*(b₁*K₁+b₂*K₂+b₃*K₃+b₄*K₄)；

wherein: y is_(i)Mixing chamber EGR, y for previous cycle_(i+1)Mixing Chamber EGR for the Current cycle, b₁、b₂、b₃And b₄Is a predetermined coefficient, K₁、K₂、K₃And K₄And h is a calculation step length for acquiring the EGR rate of the mixing cavity in the current period.

8. The apparatus for calculating the EGR rate according to claim 7, wherein the second calculating module further comprises:

a second calculation unit for calculating K according to formula (2)₁The formula (2) is:

a third calculation unit for calculating K according to formula (3)₂The formula (3) is:

a fourth calculating unit for calculating K according to formula (4)₃The formula (4) is:

a fifth calculating unit for calculating and obtaining K according to formula (5)₃The formula (5) is:

wherein: a is the gas flow passing through the throttle valve, B is the gas flow entering the intake manifold from the carbon tank, C is the gas flow entering the intake manifold from the crankshaft ventilation box, S is the total gas amount in the intake manifold in the current period, A_(i+1)To pass the EGR rate of the throttle gas, B_(i+1)EGR rate and C for canister intake manifold gas_(i+1)The EGR rate of the crankcase ventilation gases entering the intake manifold.

9. A vehicle-mounted terminal is characterized by comprising a processor and a memory;

the memory storing one or more instructions adapted to be loaded by the processor and to execute the computer program to implement an EGR rate calculation method according to any one of claims 1 to 4.

10. A storage medium having stored therein at least one instruction, at least one program, set of codes, or set of instructions, which is loaded and executed by a processor to implement a method of EGR rate calculation as claimed in any one of claims 1 to 4.

Technical Field

The invention relates to the technical field of vehicles, in particular to a method and a device for calculating an EGR rate, a vehicle-mounted terminal and a storage medium.

Background

In the background of the demand for increased fuel consumption of gasoline engines, the low pressure exhaust gas recirculation (L P-EGR) technology is considered as one of the methods with feasibility for reducing fuel consumption, and when the L P-EGR technology is used, the EGR rate needs to be accurately controlled, otherwise, a series of problems such as fire, pre-ignition, inaccurate air-fuel ratio control, and failure to achieve the expected fuel consumption are caused.

When L P-EGR closed-loop control is carried out, a real EGR rate needs to be obtained, the real EGR rate is compared with a target EGR rate in real time for closed-loop control, so accurate real EGR rate feedback needs to be obtained, and because no sensor which can directly measure the EGR rate is available on the market, the EGR rate can only be predicted, and the accuracy and the real-time performance of EGR prediction need to be ensured when the EGR rate is predicted.

According to the configuration condition of an engine, the mixing point of exhaust gas and fresh air in the engine is a position formed by the initial EGR rate before a compressor, and the exhaust gas and the fresh air enter a cylinder through a throttle valve after passing through the compressor for combustion.

The traditional Runge Kutta method predicts the EGR, and forms a new EGR rate with newly imported waste gas and fresh air according to the EGR rate at the last moment of a mixing point, at the moment, the Runge Kutta method can be used for predicting the EGR rate at the next moment according to a required set step length, and when the rotating speed of an engine is very fast or the volume of a mixing cavity is very small, a final result cannot be obtained in time, so that the timeliness of EGR rate prediction is reduced.

Disclosure of Invention

In view of the above problems in the prior art, an object of the present invention is to provide a method and an apparatus for calculating an EGR rate, a vehicle-mounted terminal, and a storage medium, which can solve the problem of the prior art that the performance of a vehicle is degraded due to a delay in calculating the EGR rate.

In order to solve the technical problems, the specific technical scheme of the invention is as follows:

in one aspect, the present invention provides a method of calculating an EGR rate, the method comprising the steps of:

acquiring the gas flow entering an intake manifold through a throttle valve, the gas flow entering the intake manifold through a carbon tank and the gas flow entering the intake manifold through a crankshaft ventilation box in the current period, wherein the gas flow comprises the exhaust gas flow and the air flow;

according to the gas flow passing through the throttle valve, the gas flow entering the intake manifold from the carbon tank and the gas flow entering the intake manifold from the crankshaft ventilation box, the EGR rate of the gas passing through the throttle valve, the EGR rate of the gas entering the intake manifold from the carbon tank and the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box are obtained;

acquiring the EGR rate of the mixing cavity in the previous period and the calculation step length of the EGR rate of the mixing cavity in the current period;

and acquiring the calculation step length of the EGR rate of the mixing cavity according to the EGR rate of the throttle gas, the EGR rate of the gas entering the intake manifold from the carbon tank, the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box, the EGR rate of the mixing cavity in the previous period and the current period, and acquiring the EGR rate of the mixing cavity in the current period.

Further, the step of calculating the mixture chamber EGR rate in the last period and the mixture chamber EGR rate in the current period comprises:

acquiring the EGR rate of the mixing cavity in the previous period, the total mass of gas in the instantaneous mixing cavity and the flow rate of gas flowing through the instantaneous mixing cavity;

acquiring the gas outflow time of the mixing chamber in the current period according to the total mass of the gas in the instantaneous mixing chamber and the flow rate of the gas flowing through the instantaneous mixing chamber;

judging whether the gas outflow time of the mixing cavity in the current period is greater than the preset time or not;

if so, taking the preset time as the current period to obtain the calculation step length of the EGR rate of the mixing cavity, and if not, taking the gas outflow time of the mixing cavity in the current period as the current period to obtain the calculation step length of the EGR rate of the mixing cavity.

Further, the obtaining the current period mixing chamber EGR rate according to the calculated step length of the mixing chamber EGR rate obtained through the EGR rate of the throttle gas, the EGR rate of the carbon canister entering the intake manifold, the EGR rate of the crank ventilation box entering the intake manifold, the EGR rate of the mixing chamber in the previous period and the current period comprises:

obtaining the EGR rate of the mixing cavity in the current period according to the formula (1):

y_(i+1)＝y_(i)+h*(b₁*K₁+b₂*K₂+b₃*K₃+b₄*K₄) (1)

wherein: y is_(i)For the last cycle mixing chamber EGR rate, y_(i+1)Mixing chamber EGR rate for the current cycle, b₁、b₂、b₃And b₄Is a predetermined coefficient, K₁、K₂、K₃And K₄And h is a calculation step length for acquiring the EGR rate of the mixing cavity in the current period.

Further, said K₁Obtained by the formula (2), said K₂Obtained by the formula (3), said K₃Obtained by the formula (4) and said K₄Obtained by equation (5):

wherein: a is the gas flow passing through the throttle valve, B is the gas flow entering the intake manifold from the carbon tank, C is the gas flow entering the intake manifold from the crankshaft ventilation box, S is the total gas amount in the intake manifold in the current period, A_(i+1)To pass the EGR rate of the throttle gas, B_(i+1)EGR rate and C for canister intake manifold gas_(i+1)The EGR rate of the crankcase ventilation gases entering the intake manifold.

In a second aspect, the present invention provides, on the basis of the method for calculating an EGR rate, an apparatus for calculating an EGR rate, the apparatus comprising:

the device comprises a first acquisition module, a second acquisition module and a control module, wherein the first acquisition module is used for acquiring the gas flow entering an intake manifold through a throttle valve, a carbon tank and a crankshaft ventilation box in the current period, and the gas flow comprises the exhaust gas flow and the air flow;

the first calculation module is used for acquiring the EGR rate of gas passing through the throttle valve, the EGR rate of gas entering the intake manifold from the carbon tank and the EGR rate of gas entering the intake manifold from the crankshaft ventilation box according to the gas flow passing through the throttle valve, the gas flow entering the intake manifold from the carbon tank and the gas flow entering the intake manifold from the crankshaft ventilation box;

the second acquisition module is used for acquiring the EGR rate of the mixing cavity in the previous period and the calculation step length of the EGR rate of the mixing cavity acquired in the current period;

and the second calculation module is used for acquiring the calculation step length of the EGR rate of the mixing cavity according to the EGR rate of the throttle gas, the EGR rate of the gas entering the intake manifold from the carbon tank, the EGR rate of the gas entering the intake manifold from the crankshaft ventilation box, the EGR rate of the mixing cavity in the previous period and the current period, and acquiring the EGR rate of the mixing cavity in the current period.

Further, the second obtaining module includes:

the first acquisition unit is used for acquiring the EGR rate of the mixing cavity in the previous period;

the second acquisition unit is used for acquiring the total mass of the gas in the instantaneous mixing cavity and the flow rate of the gas flowing through the instantaneous mixing cavity;

and the judging unit is used for judging whether the gas outflow time of the mixing cavity in the current period is greater than the preset time, if so, taking the preset time as the calculation step length of the EGR rate of the mixing cavity in the current period, and if not, taking the gas outflow time of the mixing cavity in the current period as the calculation step length of the EGR rate of the mixing cavity in the current period.

Further, the second calculation module includes:

a first calculating unit, configured to obtain the EGR rate of the mixing chamber in the current period according to formula (1), where formula (1) is:

y_(i+1)＝y_(i)+h*(b₁*K₁+b₂*K₂+b₃*K₃+b₄*K₄)，

wherein: y is_(i)For the last cycle mixing chamber EGR rate, y_(i+1)Mixing chamber EGR rate for the current cycle, b₁、b₂、b₃And b₄Is a predetermined coefficient, K₁、K₂、K₃And K₄And h is a calculation step length for acquiring the EGR rate of the mixing cavity in the current period.

Further, the second calculation module further comprises:

a second calculation unit for calculating K according to formula (2)₁The formula (2) is:

a third calculation unit for calculating K according to formula (3)₂The formula (3) is:

a fourth calculating unit for calculating K according to formula (4)₃The formula (4) is:

and

a fifth calculating unit for calculating and obtaining K according to formula (5)₃The formula (5) is:

wherein: a is air passing through a throttle valveThe volume flow, B is the gas flow entering the intake manifold from the carbon tank, C is the gas flow entering the intake manifold from the crankshaft ventilation box, S is the total gas amount in the intake manifold in the current period, A_(i+1)To pass the EGR rate of the throttle gas, B_(i+1)EGR rate and C for canister intake manifold gas_(i+1)The EGR rate of the crankcase ventilation gases entering the intake manifold.

In a third aspect, the present invention further provides a vehicle-mounted terminal, where the vehicle-mounted terminal includes a processor and a memory, where the memory stores one or more instructions, and the one or more instructions are adapted to load and execute the computer program by the processor to implement the steps of the method for calculating an EGR rate.

In a fourth aspect, the present invention further provides a storage medium having at least one instruction, at least one program, code set, or instruction set stored therein, which is loaded and executed by a processor to implement the steps of one of the EGR rate calculation methods described above.

By adopting the technical scheme, the method and the device for calculating the EGR rate, the vehicle-mounted terminal and the storage medium have the following beneficial effects that:

1. according to the method and the device for calculating the EGR rate, the vehicle-mounted terminal and the storage medium, the EGR rate in the previous period is substituted into the calculation of the EGR rate in the current period, and the accuracy of the calculation of the EGR rate is improved.

2. According to the method and the device for calculating the EGR rate, the vehicle-mounted terminal and the storage medium, the calculation of the EGR rate is closer to a final result by setting corresponding parameters, the calculation speed is higher, the delay of the calculation of the EGR rate is avoided, and the timeliness of the calculation of the EGR rate is ensured.

3. According to the method and the device for calculating the EGR rate, the vehicle-mounted terminal and the storage medium, when the gas flow rate of the engine is high or the gas volume of the mixing cavity is small, the calculation step length of the EGR rate of the mixing cavity obtained in the current period is limited, and the smooth calculation of the EGR rate is ensured.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiment or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a schematic diagram of a vehicle fuel line configuration in an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a system in an embodiment of the present description;

FIG. 3 is a flow chart illustrating a method of calculating EGR in an embodiment of the present disclosure;

fig. 4 is a detailed step diagram of step S3 in fig. 3;

FIG. 5 is a schematic diagram of a calculation device for EGR in the embodiment of the present description;

FIG. 6 is a schematic diagram of a second acquisition module of FIG. 5;

FIG. 7 is a schematic structural diagram of a vehicle-mounted terminal in an embodiment of the present specification;

FIG. 8 is a schematic diagram of a conventional Longge Kutta simulation in this specification;

FIG. 9 is a schematic diagram of an improved Longge Kutta simulation in this specification;

FIG. 10A volume of a mixing chamber in an embodiment of the present description is 2000cm³A simulation schematic diagram of (a);

FIG. 11A volume of a mixing chamber of 500cm in an example of the present specification³A simulation schematic diagram of (a);

FIG. 12A volume of a mixing chamber of an embodiment of the present specification is 100cm³A simulation schematic diagram of (a);

FIG. 13A volume of a mixing chamber of an embodiment of the present specification is 100cm³A simulation schematic of (a).

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 obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.