阅读说明：本技术 一种发动机怠速目标转速控制方法 (Engine idling target rotating speed control method ) 是由 秦龙 刘磊 赵田芳 彭红涛 于 2020-06-23 设计创作，主要内容包括：本发明涉及一种发动机怠速目标转速控制方法,包括以下步骤：根据燃烧类控制请求获取多个目标怠速,并取其中的最大值,对最大值做变化率限制,得到燃烧类目标怠速n<Sub>SetpointComb</Sub>；根据负载类控制请求获取多个目标怠速,并取其中的最大值,得到负载类目标怠速n<Sub>SetpointLoad</Sub>；将所述燃烧类目标怠速n<Sub>SetpointComb</Sub>和所述负载类目标怠速n<Sub>SetpointLoad</Sub>求和,得到目标怠速初始值n<Sub>SetpointRaw</Sub>；对所述目标怠速初始值n<Sub>SetpointRaw</Sub>进行动态调节,得到动态目标怠速转速n<Sub>SetpointDyn</Sub>；对所述动态目标怠速转速n<Sub>SetpointDyn</Sub>进行平滑处理,得到最终目标怠速转速n<Sub>SetpointFinal</Sub>；将所述发动机的怠速设置为所述最终目标怠速转速n<Sub>SetpointFinal</Sub>。本发明提供的一种发动机怠速目标转速控制方法,在计算发动机的最终目标怠速转速时考虑充足,可以避免转速过高或过低的情况,并且怠速闭环控制的稳定性高。(The invention relates to a method for controlling the idle speed target rotating speed of an engine, which comprises the following steps: obtaining a plurality of target idling speeds according to the combustion control request, taking the maximum value of the target idling speeds, and limiting the change rate of the maximum value to obtain the combustion target idling speed n SetpointComb (ii) a Obtaining a plurality of target idling speeds according to the load control request, and obtaining the maximum value of the target idling speeds to obtain the load target idling speed n SetpointLoad (ii) a Setting the combustion class target idle speed n SetpointComb And the load class target idle speed n SetpointLoad Summing to obtain a target idle speed initial value n SetpointRaw (ii) a For the target idling initial value n SetpointRaw Carrying out dynamic adjustment to obtain a dynamic target idle speed n SetpointDyn (ii) a For the dynamic target idle speed n SetpointDyn Smoothing to obtain the final target idling speed n SetpointFinal (ii) a Setting an idle speed of the engine to the final target idle speed n SetpointFinal . The invention provides an engine idling target rotating speed control methodThe method is sufficient to consider when calculating the final target idle speed of the engine, can avoid the situation that the speed is too high or too low, and has high stability of idle closed-loop control.)

1. An engine idle target speed control method characterized by comprising the steps of:

obtaining a plurality of target idling speeds according to the combustion control request, taking the maximum value of the target idling speeds, and limiting the change rate of the maximum value to obtain the combustion target idling speed n_SetpointComb；

Obtaining a plurality of target idling speeds according to the load control request, and obtaining the maximum value of the target idling speeds to obtain the load target idling speed n_SetpointLoad；

Setting the combustion class target idle speed n_SetpointCombAnd the load class target idle speed n_SetpointLoadSumming to obtain a target idle speed initial value n_SetpointRaw；

For the target idling initial value n_SetpointRawCarrying out dynamic adjustment to obtain a dynamic target idle speed n_SetpointDyn；

For the dynamic target idle speed n_SetpointDynSmoothing to obtain the final target idling speed n_{SetpointFinal}；

Setting an idle speed of the engine to the final target idle speed n_{SetpointFinal}。

2. The engine idle target speed control method as claimed in claim 1, wherein the plurality of target idle speeds of the combustion type control request specifically include:

determining a first basic target idle speed according to atmospheric pressure and real-time water temperature of an engine;

determining a second basic target idle speed according to the combustion times of the engine and the starting water temperature of the engine;

determining a third basic target idle speed according to the real-time water temperature and the atmospheric temperature of the engine;

determining a fourth basic target idle speed according to the real-time water temperature of the engine and the air inlet temperature of the engine;

and catalyst light-off, EGR control, and GPF active regeneration control correspond to the requested minimum engine idle speed, respectively.

3. The engine idle target speed control method as claimed in claim 1, wherein rate of change limiting the maximum value in the combustion type control request specifically comprises: the limit change rate is set for the target according to the engine idle speed control stability, and the limit change rate of the reduction of the speed is not lower than the limit change rate of the increase of the speed.

4. The engine idle target speed control method as claimed in claim 1, wherein the plurality of target idle speeds of the load class control request specifically include:

determining a fifth base target idle speed according to the generator load;

determining a sixth basic target idle speed according to the air conditioner load;

determining a seventh basic target idle speed according to the power steering load;

determining an eighth basic target idle speed according to the load of the headlamp;

determining a ninth basic target idle speed according to the gear of the vehicle and the oil temperature of the gearbox;

and a minimum engine idle speed requested by the transmission.

5. The engine idle target speed control method of claim 4 wherein the target idle speed initial value n is set_SetpointRawThe dynamic adjustment is carried out, and the method specifically comprises the following steps:

step a, the activation time of idle closed-loop control exceeds the preset timeSetting the dynamic target idle speed N at a time duration T1, or when the sixth basic target idle speed exceeds a preset value N1_SetpointDynIs the target idle speed initial value n_SetpointRaw；

Step b, if the step a is not satisfied, the actual rotating speed of the engine and the dynamic target idle rotating speed n in the last time period delta t_SetpointDynIf the difference does not exceed the absolute value D3 of the allowable range of the idle error, the dynamic target idle speed n is set_SetpointDynIs the target idle speed initial value n_SetpointRaw；

Step c, if the actual rotating speed of the engine and the target rotating speed initial value n are not satisfied in the step b_SetpointRawThe difference exceeds the preset value D1, and the target rotating speed is initialized to the value n_SetpointRawIncreasing a set accumulation amount D2 as the dynamic target idle speed n_SetpointDyn；

Step d, under the condition that the step c is not satisfied, setting the dynamic target idle speed n_SetpointDynIs the target idle speed initial value n_SetpointRaw。

6. The engine idle target speed control method as claimed in claim 5, characterized in that: in step a, after the condition that the idle closed-loop control activation time exceeds the preset time period T1 is met, the condition is not judged again until the engine is shut down and the vehicle is powered on again.

7. The engine idle target speed control method as claimed in claim 5, characterized in that: in step c, the target rotation speed initial value n is set_SetpointRawIncreasing the set accumulation amount D2 to obtain the dynamic target idle speed n_SetpointDynThen, maintaining the dynamic target idle speed n_SetpointDynRecovering the dynamic target idle speed n after the preset time duration T1 and T1 are ended_SetpointDynIs the target idle speed initial value n_SetpointRaw。

8. The engine idle target speed control method as claimed in claim 5, characterized in that: d1 > D2 > D3 > 0.

9. The engine idle target speed control method of claim 1, wherein for the dynamic target idle speed n_SetpointDynSmoothing to obtain the final target idling speed n_{SetpointFinal}The method specifically comprises the following steps:

monitoring the dynamic target idle speed n in real time_SetpointDynAnd calculating a limit target rotation speed n for limiting the rate of change thereof_{SetpointDynRateLim}；

If the dynamic target idle speed n is within the current time period delta t_SetpointDynIs less than or equal to a set limit rate of change, the final target idle speed n_{SetpointFinal}Is equal to the dynamic target idle speed n in the current time period delta t_SetpointDynOr equal to the limited target speed n with the rate of change limited within the current time period deltat_{SetpointDynRateLim}；

Otherwise the final target idle speed n_{SetpointFinal}The smoothing process is carried out in the following manner,wherein, T_FilterFor filtering time coefficients, n_{SetpointFinal}(z) is the final target idle speed during the previous time period.

10. The engine idle target speed control method of claim 9 wherein said calculating limits said dynamic target idle speed n_SetpointDynLimiting target speed n of change rate_{SetpointDynRateLim}The method specifically comprises the following steps:

setting the dynamic target idle speed n for a target according to engine idle speed control stability_SetpointDynAnd according to the dynamic target idle speed n in the last time period deltat_SetpointDynAnd calculating the limit change rate to obtain the limit target rotating speed n in the current time period delta t_{SetpointDynRateLim}。

Technical Field

The invention relates to the field of engine idle speed control, in particular to a method for controlling an idle speed target rotating speed of an engine.

Background

At present, idling is the most common working condition when an engine works, the problems of oil consumption, emission and NVH (noise, vibration and harshness) can be caused by overhigh idling speed, and the problems of engine shake, NVH and the like can be caused by overlow idling speed. In order to meet the increasingly strict national emission standard, improve the brand image of a host factory, and meet the higher requirements of consumers on vehicle dynamic property, economy, comfort and the like, the gasoline engine has more and more parts, so that the idle speed control of the engine of the automobile is more and more complicated.

Disclosure of Invention

The embodiment of the invention aims to provide a method for controlling the target rotating speed of the idle speed of an engine, which aims to solve the problems that the rotating speed is too high or too low and the stability of idle speed control is not high due to insufficient consideration of calculating the target idle speed of the engine in the related art.

In order to achieve the above object, an embodiment of the present invention provides an engine idle speed target rotation speed control method, including the steps of: obtaining a plurality of target idling speeds according to the combustion control request, taking the maximum value of the target idling speeds, and limiting the change rate of the maximum value to obtain the combustion target idling speed n_SetpointComb(ii) a Obtaining a plurality of target idling speeds according to the load control request, and obtaining the maximum value of the target idling speeds to obtain the load target idling speed n_SetpointLoad(ii) a Setting the combustion class target idle speed n_SetpointCombAnd the load class target idle speed n_SetpointLoadSumming to obtain a target idle speed initial value n_SetpointRaw(ii) a For the target idling initial value n_SetpointRawCarrying out dynamic adjustment to obtain a dynamic target idle speed n_SetpointDyn(ii) a For the dynamic target idle speed n_SetpointDynSmoothing to obtain the final target idling speed n_{SetpointFinal}(ii) a Setting an idle speed of the engine to the final target idle speed n_{SetpointFinal}。

In some embodiments, the plurality of target idle speeds of the combustion type control request specifically includes: determining a first basic target idle speed according to atmospheric pressure and real-time water temperature of an engine; determining a second basic target idle speed according to the combustion times of the engine and the starting water temperature of the engine; determining a third basic target idle speed according to the real-time water temperature and the atmospheric temperature of the engine; determining a fourth basic target idle speed according to the real-time water temperature of the engine and the air inlet temperature of the engine; and catalyst light-off, EGR control, and GPF active regeneration control correspond to the requested minimum engine idle speed, respectively.

In some embodiments, the rate of change limiting the maximum value of the combustion control request specifically includes: the limit change rate is set for the target according to the engine idle speed control stability, and the limit change rate of the reduction of the speed is not lower than the limit change rate of the increase of the speed.

In some embodiments, the plurality of target idle speeds of the load class control request specifically includes: determining a fifth base target idle speed according to the generator load; determining a sixth basic target idle speed according to the air conditioner load; determining a seventh basic target idle speed according to the power steering load; determining an eighth basic target idle speed according to the load of the headlamp; determining a ninth basic target idle speed according to the gear of the vehicle and the oil temperature of the gearbox; and a minimum engine idle speed requested by the transmission.

In some embodiments, the target idle speed is initialized to n_SetpointRawThe dynamic adjustment is carried out, and the method specifically comprises the following steps: step a, enabling the activation time of the idle closed-loop control to exceed a preset time length T1, or enabling the sixth basic target idle speed to exceed a preset value N1, and setting the dynamic target idle speedn_SetpointDynIs the target idle speed initial value n_SetpointRaw(ii) a Step b, if the step a is not satisfied, the actual rotating speed of the engine and the dynamic target idle rotating speed n in the last time period delta t_SetpointDynIf the difference does not exceed the absolute value D3 of the allowable range of the idle error, the dynamic target idle speed n is set_SetpointDynIs the target idle speed initial value n_SetpointRaw(ii) a Step c, if the actual rotating speed of the engine and the target rotating speed initial value n are not satisfied in the step b_SetpointRawThe difference exceeds the preset value D1, and the target rotating speed is initialized to the value n_SetpointRawIncreasing a set accumulation amount D2 as the dynamic target idle speed n_SetpointDyn(ii) a Step d, under the condition that the step c is not satisfied, setting the dynamic target idle speed n_SetpointDynIs the target idle speed initial value n_SetpointRaw。

In some embodiments, in step a, after the condition that the idle closed-loop control activation time exceeds the preset time period T1 is met, the condition is not judged again until the engine is shut down and the vehicle is powered on again.

In some embodiments, in step c, the target rotation speed is initialized to the initial value n_SetpointRawIncreasing the set accumulation amount D2 to obtain the dynamic target idle speed n_SetpointDynThen, maintaining the dynamic target idle speed n_SetpointDynRecovering the dynamic target idle speed n after the preset time duration T1 and T1 are ended_SetpointDynIs the target idle speed initial value n_SetpointRaw。

In some embodiments, D1 > D2 > D3 > 0.

In some embodiments, the dynamic target idle speed n is adjusted_SetpointDynSmoothing to obtain the final target idling speed n_{SetpointFinal}The method specifically comprises the following steps: monitoring the dynamic target idle speed n in real time_SetpointDynAnd calculating a limit target rotation speed n for limiting the rate of change thereof_{SetpointDynRateLim}(ii) a If the dynamic target idle speed n is within the current time period delta t_SetpointDynOf (2) aThe change rate is less than or equal to the set limit change rate, the final target idle speed n_{SetpointFinal}Is equal to the dynamic target idle speed n in the current time period delta t_SetpointDynOr equal to the limited target rotation speed n with the rate of change limited in the current time period_{SetpointDynRateLim}(ii) a Otherwise the final target idle speed n_{SetpointFinal}The smoothing process is carried out in the following manner,

wherein, T_FilterFor filtering time coefficients, n_{SetpointFinal}(z) is the final target idle speed during the previous time period.

In some embodiments, the calculation limits the dynamic target idle speed n_SetpointDynLimiting target speed n of change rate_{SetpointDynRateLim}The method specifically comprises the following steps: setting the dynamic target idle speed n for a target according to engine idle speed control stability_SetpointDynAnd according to the dynamic target idle speed n in the last time period deltat_SetpointDynAnd calculating the limit change rate to obtain the limit target rotating speed n in the current time period delta t_{SetpointDynRateLim}。

The technical scheme provided by the invention has the beneficial effects that:

the embodiment of the invention provides an engine idle speed target rotating speed control method, which considers a plurality of target idle speeds of an engine combustion control request when determining the final target idle speed, limits the change rate of the maximum value of the target idle speeds, considers the idle speed condition of a finished vehicle load control request, dynamically adjusts the sum of the combustion target idle speed and the load target idle speed, determines the final target idle speed according to smoothing treatment, avoids overlarge parameter adjustment of Proportional Integral Derivative (PID) when the difference between the final target idle speed and the actual rotating speed of an engine is overlarge during idle closed-loop control, improves the response rate of closed-loop control, improves the stability of closed-loop control, is sufficient in consideration when calculating the final target idle speed of the engine, and can avoid the condition of overhigh or overlow rotating speed, and the stability of the idle closed-loop control is high.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a flowchart illustrating steps of a method for controlling an idle target speed of an engine according to an embodiment of the present invention;

FIG. 2 is a flowchart illustrating steps of dynamically adjusting a target idle speed initial value of a method for controlling an idle speed target speed of an engine according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating steps of smoothing a dynamic target idle speed in an engine idle speed target control method according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. 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.

The embodiment of the invention provides an engine idle speed target rotating speed control method, which can solve the problems of overhigh or overlow rotating speed and low idle speed control stability caused by insufficient consideration of engine idle speed calculation in the related art.

Referring to fig. 1, an embodiment of the present invention provides a method for controlling an idle target speed of an engine, by which an actual speed of the engine is monitored and adjusted in real time with Δ t as a time period, the method including the steps of:

s101: obtaining a plurality of target idling speeds according to the combustion control request, taking the maximum value of the target idling speeds, and limiting the change rate of the maximum value to obtain the combustion target idling speed n_SetpointComb。

In some optional embodiments, in S101, when obtaining a plurality of target idling speeds according to the combustion control request, the plurality of target idling speeds may specifically include: determining a first basic target idle speed according to atmospheric pressure and real-time water temperature of an engine; determining a second basic target idling speed according to the combustion times of the engine and the starting water temperature of the engine, wherein the combustion times of the engine are the sum of ignition times of all cylinders from the start of the engine, and the starting water temperature of the engine refers to the water temperature of the engine at the moment of starting; determining a third basic target idle speed according to the real-time water temperature and the atmospheric temperature of the engine; determining a fourth basic target idle speed according to the real-time water temperature of the engine and the air inlet temperature of the engine; wherein the first, second, third, and fourth base target idle speeds are identified based on current operating conditions of the engine for the purpose of improving NVH and fuel economy during idle; the first to fourth basic target idle speed are determined by adopting the prior technical scheme based on the conception when the engine working condition is bad (such as the temperature pressure signal is too small, the combustion of the engine is poor, the engine speed needs to be increased to improve NVH, the combustion condition of the engine is better after the temperature is increased, the idle speed is designed for the purpose of improving the idle fuel economy, and simultaneously avoiding the NVH problem).

In some embodiments, in S101, when obtaining a plurality of target idling speeds according to the combustion control request, the plurality of target idling speeds may further include: a minimum engine idle speed for catalyst light-off request; minimum engine idle speed requested by EGR (exhaust gas recirculation) control; and GPF (gasoline engine particulate trap) active regeneration controlled minimum engine idle speed; wherein, when the catalyst is ignited and the GPF is actively regenerated, the temperature of an exhaust system (the catalyst and the GPF) is required to be increased by increasing the idling speed so as to increase the air inflow of the engine, so that the ignition of the catalyst and the active regeneration of the GPF are improved, and the operation of the EGR can cause the idling speed of the engine to fluctuate, so that the idling speed is required to be increased (or not required).

In some optional embodiments, in S101, after obtaining a plurality of target idling speeds according to the combustion control request, a maximum value may be selected from among the 7 idling speeds, which may be the first base target idling speed, the second base target idling speed, the third base target idling speed, the fourth base target idling speed, the lowest engine idling speed requested by the catalyst light-off, the lowest engine idling speed requested by the EGR control, and the lowest engine idling speed requested by the GPF active regeneration control.

In some embodiments, in S101, limiting the change rate of the maximum value in the combustion control request may specifically include: in the embodiment of the present application, it is preferable to set the maximum rotation speed reduction limit change rate to-800 rpm/s and the rotation speed increase limit change rate to 120rpm/s in the combustion control request, and set the maximum value as the combustion target idle speed n of the engine after the maximum value is subjected to the change rate limitation_SetpointCombWherein if the variation rate of the maximum value in the combustion control request in the current time period is smaller than the set limit variation rate, the combustion target idle speed n_SetpointCombEqual to the maximum of the combustion type control requests in the current time period; if the variation rate of the maximum value in the combustion control request in the current time period is greater than or equal to the set limit variation rate, the combustion target idle speed n_SetpointCombLimiting the rate of change to a maximum value equal to the limited rate of change.

S102: obtaining a plurality of target idling speeds according to the load control request, and obtaining the maximum value of the target idling speeds to obtain the loadClass target idle speed n_SetpointLoad。

In some embodiments, in S102, when obtaining a plurality of target idling speeds according to the load-class control request, the plurality of target idling speeds of the load-class control request may specifically include: determining a fifth base target idle speed according to the generator load; determining a sixth basic target idle speed according to the air conditioner load; determining a seventh basic target idle speed according to the power steering load; determining an eighth basic target idle speed according to the load of the headlamp; determining a ninth basic target idle speed according to the gear of the vehicle and the oil temperature of the gearbox; and a minimum engine idle speed requested by the transmission; taking one maximum value of the above 6 idle speed as a load target idle speed n_SetpointLoad(ii) a When the sixth basic target idle speed is determined, the specific operation may be that the air conditioner clutch is firstly combined and then the sixth basic speed is set, and the sixth basic speed is quitted after the air conditioner clutch is disconnected for a period of time; and when the ninth basic target idle speed is determined, if the gear of the vehicle is P gear or N gear, looking up a table 1 according to the oil temperature of the gearbox, and if the vehicle is at other gears, looking up a table 2 according to the oil temperature of the gearbox.

TABLE 1

Oil temperature (. degree. C.)	-30	-20	-10	0	20	40	80	100
									Rotational speed r/s	900	870	850	820	800	780	750	720

TABLE 2

Oil temperature (. degree. C.)	-30	-20	-10	0	20	40	80	100
									Rotational speed r/s	1200	1200	1115	1050	950	850	720	720

S103: setting the combustion class target idle speed n_SetpointCombAnd the load class target idle speed n_SetpointLoadSumming to obtain a target idle speed initial value n_SetpointRaw。

In some embodiments, in S103, the target idle speed initial value n is obtained_SetpointRawComprises the following steps: n is_SetpointRaw＝n_SetpointComb+n_SetpointLoad。

S104: for the target idling initial value n_SetpointRawCarrying out dynamic adjustment to obtain a dynamic target idle speed n_SetpointDyn。

In some embodiments, in S104, the target idle speed is adjusted to the initial value n_SetpointRawWhen dynamic adjustment is performed, the following steps (see fig. 2) may be specifically included:

sa, after an idle closed-loop control flag bit is activated and the time exceeds a preset time length T1, setting the dynamic target idle speed n_SetpointDynIs the target idle speed initial value n_SetpointRawAnd once the condition is met, the condition is not judged again until the vehicle is powered on after the engine is shut down; alternatively, the dynamic target idle speed N is set once the sixth basic idle speed determined by the air conditioning load exceeds a preset value N1_SetpointDynIs the target idle speed initial value n_SetpointRaw(ii) a It is contemplated herein that the air conditioning load doesWhen the fixed idling speed is higher, the influence of the air conditioner opening on the idling speed is higher, the speed control needs faster response, and the interference of the air conditioner opening on the engine speed fluctuation is avoided, so that the NVH of the vehicle is deteriorated.

Sb, if the actual rotating speed of the engine monitored in real time and the dynamic target idle rotating speed n in the last time period delta t are not met in the step a_SetpointDynThe difference does not exceed the absolute value D3(D3 > 0) of the allowable range of the idle error, the dynamic target idle speed n can be set immediately_SetpointDynIs the target idle speed initial value n_SetpointRaw(ii) a The dynamic target idle speed n between the actual speed of the engine and the last time period Deltat_SetpointDynBy quickly adjusting the dynamic target idle speed n when the difference is small_SetpointDynThe influence on the idle speed fluctuation is within the allowable range of the idle speed fluctuation.

Sc, if the actual rotation speed of the engine and the target rotation speed initial value n are not satisfied in the step b_SetpointRawThe difference exceeds the preset value D1(D1 > D3), and the target rotating speed is initialized to the value n_SetpointRawIncreasing the set accumulation amount D2(D1 > D2 > D3) to obtain a new idle speed n_SetpointRaw+ D2 as the dynamic target idle speed n_SetpointDynWhen the rotating speed error is large, the dynamic adjustment of the target rotating speed is limited to be overlarge, so that the response time of idle closed-loop control is prevented from being delayed and the closed-loop control precision is prevented from being reduced; new idle speed n_SetpointRaw+ D2 (i.e. the dynamic target idle speed n)_SetpointDyn) Maintaining a preset time length T1, and immediately recovering the dynamic target rotating speed n after the time T1 is ended_SetpointDynIs the target idle speed initial value n_SetpointRaw(ii) a Timing a time length T1 through a timer, resetting the timer to be 0 when the step b is met, and starting timing from 0 again when the step c is met again; due to the dynamic target idle speed n_SetpointDynIf the difference between the actual rotating speed of the engine and the dynamic target idling rotating speed n is large, the dynamic target idling rotating speed n is directly adjusted_SetpointDynIs the initial value n of the target rotating speed_SetpointRawWill close to idle speedLoop control has an effect on the NVH of the vehicle.

Sd, in case step c is not satisfied, setting the dynamic target idle speed n_SetpointDynIs the target idle speed initial value n_SetpointRaw。

The priority of the step a is highest, the priority of the step b is next to the priority of the step c, the priority of the step d is lowest, and the dynamic target idle speed n is determined according to the steps_SetpointDynAvoiding the dynamic target idle speed n during idle closed-loop control_SetpointDynWhen the difference between the actual rotation speed of the engine and the actual rotation speed of the engine is too large, the PID parameter is adjusted too large, the response rate of the closed-loop control is improved (the smaller the adjustment rate is, the lower the stability of the closed-loop control may be), and in the step of dynamic adjustment, the last time period Δ t may specifically refer to the M-1 th time period before S101, while the current time period is the mth time period, the time interval between the last time period and the current time period is Δ t, and dynamic adjustment may be performed only once in each time period Δ t according to the step of dynamic adjustment.

S105: for the dynamic target idle speed n_SetpointDynSmoothing to obtain the final target idling speed n_{SetpointFinal}。

In some embodiments, in S105, the dynamic target idle speed n is adjusted_SetpointDynWhen the smoothing is carried out, the dynamic target rotating speed n can be monitored in real time_SetpointDynMonitoring the actual rotating speed of the engine and the target idling initial value n with delta t as a fixed time period_SetpointRawAnd calculating the dynamic target speed n_SetpointDyn。

In some embodiments, in S105, the dynamic target idle speed n is adjusted_SetpointDynWhen the smoothing is performed, the dynamic target idle speed n can be monitored in real time_SetpointDynAnd according to the dynamic target idle speed n_SetpointDynCalculating the dynamic target idle speed n limited_SetpointDynLimiting target speed n of change rate_{SetpointDynRateLim}(i.e., S301 in FIG. 3), wherein the information may be based on the hairSetting the dynamic target idle speed n for the target of the engine idle speed control stability_SetpointDynAccording to the set limit change rate and the dynamic target idle speed n in the last time period delta t_SetpointDynCalculating the limited target speed n in the current time period delta t_{SetpointDynRateLim}In the embodiment of the present application, it is preferable to set the dynamic target idle rotation speed n_SetpointDynThe decrease limit change rate of (2) is-1000 rpm/s and the increase limit change rate is 220 rpm/s; if the dynamic target idle speed n is within the current time period delta t_SetpointDynIs less than the set limit rate of change, the dynamic target idle speed n within the current time period deltat is indicated_SetpointDynIs small, the final target idle speed n is taken_{SetpointFinal}Is equal to the dynamic target idle speed n in the current time period delta t_SetpointDyn(ii) a If the dynamic target idle speed n is within the current time period delta t_SetpointDynIs equal to the set limit change rate, the final target idle rotation speed n is taken_{SetpointFinal}Is equal to the limit target speed n in the current time period deltat_{SetpointDynRateLim}(i.e., S302 in fig. 3); otherwise the final target idle speed n_{SetpointFinal}The smoothing process is carried out in the following manner,

wherein, T_FilterIs a filter time coefficient; n is_{SetpointFinal}(z) is the final target idle speed within the previous time period Δ t, and in the step of smoothing, the previous time period Δ t may specifically refer to the M-1 th time period before S101, while the current time period is the mth time period, and the time interval between the previous time period and the current time period is Δ t, and in each time period Δ t, only the dynamic target idle speed n may be subjected to the step of smoothing_SetpointDynCarrying out primary dynamic adjustment; and the final target idle rotation speed n_{SetpointFinal}The initial values of (i.e., the values at which the vehicle is powered on) of (1) are: if full ofThe dynamic target idle speed n in the current time period_SetpointDynIs less than or equal to a set limit rate of change, the final target idle speed n is set_{SetpointFinal}Is set as the dynamic target idle speed n in the current time period_SetpointDynOr the limit target rotation speed n in the current time period_{SetpointDynRateLim}(ii) a Otherwise, the final target idle speed n is set_{SetpointFinal}Is set as the current dynamic target rotation speed n_SetpointDyn(ii) a By aiming at the dynamic target rotating speed n_SetpointDynPerforming smoothing to obtain the final target idle speed n_{SetpointFinal}And idle speed vibration caused by poor idle closed-loop control precision due to overlarge target idle speed adjustment is avoided, and NVH of the vehicle is reduced.

S106: setting an idle rotation speed of the engine to the final target idle rotation speed n_SetpointDyn(ii) a And the idle speed of the engine is adjusted in real time to improve the stability of idle closed-loop control.

That is, the final target idle rotation speed n is calculated once every time period Δ t according to the steps of the engine idle target rotation speed control methods S101 to S106 described above_SetpointDynAnd further adjusting the idle speed of the engine to form closed-loop control.

The principle of the engine idle speed target rotation speed control method provided by the embodiment of the invention is as follows:

when the final target idle speed is determined, not only a plurality of target idle speeds of the engine combustion control request are considered, the change rate of the maximum value is limited, but also the idle speed condition of the whole vehicle load control request is considered, the sum of the combustion target idle speed and the load target idle speed is dynamically adjusted to obtain the dynamic target idle speed, the dynamic target idle speed is finally smoothed to determine the final target idle speed, the condition that the parameter adjustment of Proportional Integral Derivative (PID) is overlarge when the difference between the final target idle speed and the actual speed of the engine is overlarge during the idle closed-loop control is avoided, the response rate of the closed-loop control is improved, and the stability of the closed-loop control is improved, therefore, the condition that the speed is overlarge or overlow is avoided when the final target idle speed of the engine is calculated, and the stability of the idle closed-loop control is high.

In the description of the present invention, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

It is to be noted that, in the present invention, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.