阅读说明：本技术 一种串联模式燃烧判断的方法及使用该方法的混动汽车 (Method for judging series mode combustion and hybrid electric vehicle using same ) 是由 张春娇 贾江涛 周欣 郑建波 陈苏佑 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种串联模式燃烧判断的方法及使用该方法的混动汽车。该方法根据发动机的扭矩判断,在扭矩判断使能条件下,记录在一定循环次数内发动机实际扭矩与发动机预估扭矩的差值大于设定值的次数,可以准确的判断出车辆在混动串联模式且氧传传感器未活化下的发动机燃烧判断,避免出现后处理系统烧蚀并堵塞的现象,提升了系统的安全性。(The invention discloses a method for judging series mode combustion and a hybrid electric vehicle using the method. According to the method, the times that the difference value between the actual torque of the engine and the estimated torque of the engine is larger than the set value within a certain cycle time are recorded under the torque judgment enabling condition according to the torque judgment of the engine, the engine combustion judgment of the vehicle in a hybrid series mode without activation of the oxygen sensor can be accurately judged, the phenomena of ablation and blockage of an after-treatment system are avoided, and the safety of the system is improved.)

1. A method of series mode combustion determination based on engine torque determination, comprising:

the method comprises the following steps: acquiring a driving mode of a vehicle, an oxygen sensor state, and an actual torque value M of an engine₁Circulation counter K₁Adding 1;

step two: judging whether the torque judgment enabling condition is met or not, and if the torque judgment enabling condition is met, calculating the estimated torque value M of the engine₂If the enabling condition is not met, the torque judgment is quitted;

step three: determining the actual torque value M of the engine₁And the estimated torque value M₂Whether or not the difference of (a) is greater than a set value M_bIf not greater than the set value M_bThe output engine is in a combustion state, and if the output engine is larger than a set value M_bThen the diagnosis counter K₂Adding 1;

step four: judging cycle counter K₁Whether it is equal to the set value K of the cycle times_DiagCountIf it is less than the set value K of the cycle times_DiagCountRepeating the first step to the fourth step, if the number of the cycles is equal to the set value K_DiagCountStep five is entered and the counter K is cycled₁Clearing;

step five: diagnostic counter K₂Whether or not it is larger than a set value K_DiagCount*K_rationFailIf it is greater than the set value K_DiagCount*K_rationFailOutputting that the engine is in an unburned state, and if the output voltage is not more than a set value K_DiagCount*K_rationFailThe output engine is in a combustion state.

2. The method of series mode combustion determination of claim 1, wherein: in the second step, torqueThe determination enabling conditions include that the vehicle is in a series mode, that the oxygen sensor is not activated and is in a non-fuel closed-loop mode, and that the engine actual torque value M is₁Greater than enable condition setpoint M_a。

3. The method of series mode combustion determination of claim 2, wherein: the enable condition setting value M_aThe value range of (a) is-120 to-60 N.m.

4. The method of series mode combustion determination according to claim 1 or 2, characterized in that: in the first step, the actual torque value M of the engine₁＝m*K_{Conv_coff}*K_{Comb_coff}*K_IMEPTorque-M_FricPump(ii) a Where m is the intake air quantity, K_{Conv_coff}Is the fuel conversion efficiency, K_{Comb_coff}Is the ignition efficiency, K_IMEPTorqueIs the mean effective transformation into the torque coefficient, M_FricPumpFriction work and pumping loss torque.

5. The method of series mode combustion determination according to claim 1 or 2, characterized in that: in the second step, the estimated torque value M of the engine₂＝N_{p1_de}*J_{p1_total}2 x pi/60; wherein N is_{p1_de}Is P₁Rate of change of system speed, J_{p1_total}Is P₁System moment of inertia, J_{p1_total}The value is 0.242.

6. The method of series mode combustion determination of claim 5, wherein:

said N is_{p1_de}＝(N_p1(n)-N_p1(n-1))/Δ t, wherein

When N is present_{Genertor_crank}<N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}；

When N is present_{Genertor_crank}>＝N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}(1-K_filter)₊N_eng*K_filter，K_filter(n)＝max(K_filter(n-1)+0.1,1)；

Wherein N is_engIs the engine speed, N_GenertorAs generator speed, N_{Genertor_crank}For conversion to crankshaft-side generator speed, N_EngEstSwitchThe engine speed is limited and ranges from 800 to 1400rpm, delta t running time, K_{Gear_ratio}Is the ratio of the motor system to the crankshaft gear, N_{p1_de}Is P₁Rate of change of system speed, K_filterN is a sampling time point.

7. The method of series mode combustion determination according to claim 1 or 2, characterized in that: the set value M_bThe range of (A) is 10 to 80 N.m.

8. The method of series mode combustion determination according to claim 1 or 2, characterized in that: the cycle number set value K_DiagCountThe range of (A) is 200 to 1000.

9. The method of series mode combustion determination according to claim 1 or 2, characterized in that: the set ratio K_rationFailThe range of (A) is 0.5 to 0.8.

10. A hybrid vehicle comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the processor, when executing the program, performs the steps of the method according to any of claims 1-9.

Technical Field

The invention relates to the technical field of automobile control, in particular to a method for judging series mode combustion and a hybrid automobile using the method.

Background

Under the current technical level and application conditions, the hybrid electric vehicle is the vehicle model with the most industrialized and marketized prospects in the electric vehicles. Hybrid vehicles typically have two energy sources: the power battery and the fuel engine have two driving modes of series connection and parallel connection, the clutch is disconnected in the series connection state, the engine charges the generator, and the driving motor outputs torque.

When some faults cause that the engine does not burn or burns incompletely, but the vehicle can still drive to move forwards through the output torque of the motor, if the VECU (vehicle and engine control unit) cannot accurately identify the combustion state of the engine and still executes a torque output command, excessive unburnt fuel oil enters the post-processing system, meanwhile, the fuel oil is spontaneously combusted when oxygen and temperature in the post-processing system reach certain values, and the phenomenon of ablation and blockage of the post-processing system occurs in serious cases.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for judging the series mode combustion capable of accurately feeding back the combustion state of an engine and a hybrid vehicle type thereof.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method of series mode combustion determination based on engine torque determination, comprising: the method comprises the following steps: acquiring a driving mode of a vehicle, an oxygen sensor state, and an actual torque value M of an engine₁Circulation counter K₁Adding 1; step two: judging whether the torque judgment enabling condition is met or not, and if the torque judgment enabling condition is met, calculating the estimated torque value M of the engine₂If the enabling condition is not met, the torque judgment is quitted; step three: determining the actual torque value M of the engine₁And the estimated torque value M₂Whether or not the difference of (a) is greater than a set value M_bIf not greater than the set value M_bThe output engine is in a combustion state, and if the output engine is larger than a set value M_bThen the diagnosis counter K₂Adding 1; step four: judging cycle counter K₁Whether it is equal to the set value K of the cycle times_DiagCountIf it is less than the set value K of the cycle times_DiagCountRepeating the first step to the fourth step, if the number of the cycles is equal to the set value K_DiagCountStep five is entered and the counter K is cycled₁Clearing; step five: diagnostic counter K₂Whether or not it is larger than a set value K_DiagCount*K_rationFailIf it is greater than the set value K_DiagCount*K_rationFailOutputting that the engine is in an unburned state, and if the output voltage is not more than a set value K_DiagCount*K_rationFailThe output engine is in a combustion state.

According to the technical scheme, in the second step, the torque judgment enabling condition comprises that the vehicle is in a series mode, the oxygen sensor is not activated and is in a non-fuel closed-loop mode, and the actual torque value M of the engine₁Greater than enable condition setpoint M_a。

According to the technical scheme, the enabling condition set value M_aThe value range of (a) is-120 to-60 N.m.

According to the technical scheme, in the first step,

actual torque value M of engine₁＝m*K_{Conv_coff}*K_{Comb_coff}*K_IMEPTorque-M_FricPump；

Where m is the intake air quantity, K_{Conv_coff}Is the fuel conversion efficiency, K_{Comb_coff}Is the ignition efficiency, K_IMEPTorqueIs the mean effective transformation into the torque coefficient, M_FricPumpFriction work and pumping loss torque.

According to the technical scheme, in the second step, the estimated torque value M of the engine₂＝N_{p1_de}*J_{p1_total}2 x pi/60; wherein N is_{p1_de}Is P₁Rate of change of system speed, J_{p1_total}Is P₁System moment of inertia, J_{p1_total}The value is 0.242.

According to the technical scheme, N is_{p1_de}＝(N_p1(n)-N_p1(n-1))/Δ t, wherein

When N is present_{Genertor_crank}<N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}；

When N is present_{Genertor_crank}>＝N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}(1-K_filter)₊N_eng*K_filter，K_filter(n)＝max(K_filter(n-1)+0.1,1)；

Wherein N is_engIs the engine speed, N_GenertorAs generator speed, N_{Genertor_crank}For conversion to crankshaft-side generator speed, N_EngEstSwitchThe engine speed is limited and ranges from 800 to 1400rpm, delta t running time, K_{Gear_ratio}Is the ratio of the motor system to the crankshaft gear, N_{p1_de}Is P₁Rate of change of system speed, K_filterN is a sampling time point.

According to the technical scheme, the set value M_bThe range of (A) is 10 to 80 N.m.

According to the technical scheme, the cycle number set value K_DiagCountThe range of (A) is 200 to 1000.

According to the technical scheme, the set proportion K_rationFailThe range of (A) is 0.5 to 0.8.

According to the technical scheme, the hybrid electric vehicle comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, and is characterized in that: the processor, when executing the program, performs the steps of the method according to any of claims 1-9.

The invention has the following beneficial effects:

according to the invention, a torque judgment scheme is adopted, and the times that the difference value between the actual torque of the engine and the estimated torque of the engine is greater than a set value within a certain cycle number are recorded under the torque judgment enabling condition, so that the combustion judgment of the engine of the vehicle in a hybrid series mode without activation of the oxygen sensor can be accurately judged, the phenomena of ablation and blockage of an aftertreatment system are avoided, and the safety of the system is improved.

Drawings

Fig. 1 is a flowchart of a hybrid vehicle series mode oxygen inactive state combustion determination.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.

Referring to fig. 1, the present invention provides a method for determining a series mode combustion, which comprises the following main steps according to the torque determination of an engine.

The method comprises the following steps: acquiring a driving mode of a vehicle, an oxygen sensor state, and an actual torque value M of an engine₁Circulation counter K₁And adding 1. Actual torque value M of engine₁＝m*K_{Conv_coff}*K_{Comb_coff}*K_IMEPTorque-M_FricPumpWhere m is the intake air quantity, K_{Conv_coff}Is the fuel conversion efficiency, K_{Comb_coff}Is the ignition efficiency, K_IMEPTorqueIs the mean effective transformation into the torque coefficient, M_FricPumpFriction work and pumping loss torque.

Step two: judging whether the torque judgment enabling condition is met or not, and if the torque judgment enabling condition is met, calculating the estimated torque value M of the engine₂(ii) a And if the enabling condition is not met, quitting the torque judgment. The torque judgment enabling conditions comprise that the driving mode of the vehicle is in a series mode, the oxygen sensor is not activated and is in a non-fuel closed loop mode, and the actual torque value M of the engine₁Greater than enable condition setpoint M_a，M_aThe value range of (a) is-120 to-60 N.m, and-100 N.m is selected in the embodiment.

The predicted torque value of the engine is calculated as follows: m₂＝N_{p1_de}*J_{p1_total}*2*π/60；

Wherein N is_{p1_de}Is P₁Rate of change of system speed, J_{p1_total}Is P₁System moment of inertia, J_{p1_total}The value is 0.242.

Said N is_{p1_de}＝(N_p1(n)-N_p1(n-1))/Δ t, wherein

When N is present_{Genertor_crank}<N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}；

When N is present_{Genertor_crank}>＝N_EngEstSwitchWhen N is present_p1＝N_Genertor/K_{Gear_ratio}(1-K_filter)₊N_eng*K_filter，K_filter(n)＝max(K_filter(n-1)+0.1,1)；

Wherein N is_engIs the engine speed, N_GenertorAs generator speed, N_{Genertor_crank}For conversion to crankshaft-side generator speed, N_EngEstSwitchThe engine speed is limited to 800-1400 rpm (1100 rpm is selected in this embodiment), Δ t running time, K_{Gear_ratio}Is the ratio of the motor system to the crankshaft gear, N_{p1_de}Is P₁Rate of change of system speed, K_filterN is a sampling time point.

Step three: judging whether the difference value between the actual torque value and the estimated torque value of the engine is larger than a set value M or not_b，M_bThe range of (A) is 10-80 N.m, and in the embodiment, 30 N.m is selected; if not greater than the set value M_bThe output engine is in a combustion state, and if the output engine is larger than a set value M_bThen the diagnosis counter K₂And adding 1.

Step four: circulation counter K for diagnosis₁Whether it is equal to the set value K of the cycle times_DiagCount，K_DiagCountThe range of (1) is 200-1000, and 600 is selected in the embodiment; if the number of cycles is less than the set value K_DiagCountRepeating the first step to the fourth step; if equal to the set value K of the cycle times_DiagCountStep five is entered and the counter K is cycled₁And (6) clearing.

Step five: diagnostic counter K₂Whether or not it is larger than a set value K_DiagCount*K_rationFailSetting the ratio K_rationFailThe value range of (1) is 0.5-0.8, and the value range of the embodiment is 0.7; if the value is more than the set value K_DiagCount*K_rationFailOutputting that the engine is in an unburned state, and if the output voltage is not more than a set value K_DiagCount*K_rationFailThe output engine is in a combustion state; the diagnostic counter K is cleared.

A hybrid vehicle determines the combustion state of a hybrid vehicle-type series mode engine using the above method. The vehicle comprises a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the method when executing the program.

The above is only a preferred embodiment of the present invention, and certainly, the scope of the present invention should not be limited thereby, and therefore, the present invention is not limited by the scope of the claims.