Engine cold start flexible control strategy

Abstract

An engine cold start flexible control strategy, comprising the following steps: S101, acquiring working parameters of an engine at a current time, and sorting same according to a descending sequence of the influence coefficients of the working parameters, so as to obtain a working parameter set; S102, if it is determined that one of the working parameters is greater than or equal to a corresponding preset parameter threshold value, proceeding to step S103, otherwise, returning to step S101; and S103, on the basis of a preheating duration curve and a preheating temperature curve corresponding to the working parameters greater than or equal to the preset parameter threshold value, obtaining a preheating duration and a preheating temperature for engine preheating. By means of analog simulation experiments, the preheating duration curve and the preheating temperature curve corresponding to different working parameters of the engine are obtained, and a preheating duration and a preheating temperature for cold starting of the engine are precisely controlled on the basis of the working parameters of the engine at the current time in combination with a relay.

Description

A flexible control strategy for engine cold start Technical Field

[0001] The present invention relates to the technical field of engine cold start, and more particularly to an engine cold start flexible control strategy. Background Art

[0002] When the engine is cold started, the engine is in a low-temperature state, the evaporation rate of the fuel slows down, and the viscosity of the lubricating oil increases, resulting in increased friction in the engine, bringing additional load and more wear to the engine. In addition, the combustion efficiency of the engine is low during cold start, and emissions increase, which has an adverse impact on the environment.

[0003] In the current automotive industry, the mainstream technical route for achieving engine preheating and starting is to control the heating of the air intake grille through an external auxiliary system or a single ambient temperature sensor; the external auxiliary system is to assist the engine in preheating by adding additional heating devices, such as flame jet preheaters or electric wire preheaters, etc.; the single ambient temperature sensor is to add a similar heating device in the air intake grille according to a preset temperature threshold to increase the engine intake temperature, thereby achieving engine preheating and starting.

[0004] However, when the external auxiliary system or the intake air temperature sensor fails, no additional heat energy can be provided to assist in engine preheating, resulting in difficulty in starting the engine in a low temperature environment.

[0005] Summary of the Invention

[0006] The present invention provides an engine cold start flexible control strategy to solve the technical problems in the above-mentioned background technology.

[0007] The present invention provides an engine cold start flexible control strategy, comprising the following steps:

[0008] Step S101, obtaining the current engine operating parameters, and sorting the operating parameters in descending order according to the influence coefficient of each operating parameter to obtain an operating parameter set;

[0009] The engine's operating parameters include: intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure;

[0010] Step S102: traverse the operating parameter set in descending order of influence coefficients to determine whether each operating parameter is greater than or equal to a preset parameter threshold value of each operating parameter. If any operating parameter is greater than or equal to the corresponding preset parameter threshold value, it indicates that engine preheating is started and the process proceeds to step S103; otherwise, the process returns to step S101.

[0011] Step S103 , obtaining the preheating time and preheating temperature of the engine preheating according to the preheating time curve and preheating temperature curve corresponding to the working parameters that are greater than or equal to the preset parameter threshold.

[0012] Furthermore, the influence coefficient of each working parameter is obtained through the simulation experiment platform, including the following steps:

[0013] Step S201, selecting one of the operating parameters as an independent variable, the remaining operating parameters as fixed constants, and the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine reaching the rated speed as dependent variables;

[0014] Step S202: Under the first constraint condition of each operating parameter, randomly generate an operating parameter as an independent variable, input the operating parameter as the independent variable and the remaining operating parameters as fixed constants into the simulation experiment platform, and record the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine at the rated speed as dependent variables;

[0015] Step S203, repeating step S202 M times, where M also represents the number of simulation experiments, and obtaining the influence coefficient of the working parameter as the independent variable;

[0016] The calculation formula of the influence coefficient of the working parameter as an independent variable is as follows:

[0017] Where R represents the influence coefficient of the working parameter as the independent variable, M represents the number of simulation experiments, and y i It represents the time it takes for the engine to reach the rated speed in the i-th simulation experiment, in seconds, z i represents the fuel consumption value of the engine reaching the rated speed in the i-th simulation experiment, in milliliters, α and β represent the first weight parameter and the second weight parameter respectively, the sum of the first weight parameter and the first weight parameter is 1, b1 and b2 represent the first bias parameter and the second bias parameter respectively, the sum of the first bias parameter and the second bias parameter is 1;

[0018] Step S204 , repeating steps S201 to S203 to obtain the influence coefficients of the remaining working parameters respectively.

[0019] Furthermore, the first constraint condition of the operating parameters includes: the randomly generated upper and lower limits of the intake temperature, the randomly generated upper and lower limits of the ambient temperature, and the randomly generated upper and lower limits of the cooling water temperature, which correspond to 0 degrees Celsius and the lower limit of the engine operating temperature, respectively; the randomly generated upper and lower limits of the atmospheric pressure are both custom parameters.

[0020] Furthermore, the number M of simulation experiments is a custom parameter and is a positive integer greater than 1.

[0021] Furthermore, the first weight parameter, the second weight parameter, the first bias parameter, and the second bias parameter are all custom parameters, and are real numbers greater than 0 and less than 1.

[0022] Furthermore, the preset parameter threshold of the intake air temperature, the preset parameter threshold of the ambient temperature, the preset parameter threshold of the cooling water temperature, and the preset parameter threshold of the atmospheric pressure are all custom parameters.

[0023] Furthermore, obtaining the preheating time curve and preheating temperature curve associated with each working parameter through the simulation experiment platform includes the following steps:

[0024] Step S301, randomly generating N groups of engine operating parameters, engine preheating time and preheating temperature that meet the second constraint condition;

[0025] Step S302: Input the operating parameters, preheating time, and preheating temperature of each group of engines that meet the second constraint into the simulation experiment platform, and record the time it takes for each group of engines to reach the rated speed;

[0026] Step S303: constructing four first 2-tuples and four second 2-tuples based on the engine operating parameters, preheating time, and preheating temperature corresponding to the minimum value of the time it takes for the engine to reach the rated speed. The four first 2-tuples are respectively represented as: {A1, B}, {A2, B}, {A3, B}, {A4, B}; and the four second 2-tuples are respectively represented as: {A1, C}, {A2, C}, {A3, C}, {A4, C}, where A1, A2, A3, and A4 represent the intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure, B represents the preheating time for engine preheating, and C represents the preheating temperature for engine preheating.

[0027] Step S304 , repeating steps S301 to S303 , constructing a preheating time curve of each operating parameter by least squares fitting based on the first binary group, and constructing a preheating temperature curve of each operating parameter by least squares fitting based on the second binary group.

[0028] Furthermore, N is a custom parameter.

[0029] Furthermore, in addition to the first constraint condition, the second constraint condition further includes: the upper limit and lower limit of the preheating time of the engine preheating are both custom parameters.

[0030] Furthermore, the preheating time and preheating temperature of the engine are controlled by an electromagnetic time relay.

[0031] The beneficial effects of the present invention are as follows: the present invention obtains the preheating time curve and preheating temperature curve of different engine operating parameters through simulation experiments, and obtains the preheating time and preheating temperature according to the engine operating parameters at the current time, and combines the relay to accurately control the preheating time and preheating temperature of the engine cold start. In addition, there is no need to add any auxiliary devices, which reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a flow chart of an engine cold start flexible control strategy according to the present invention;

[0033] FIG2 is a flow chart of obtaining the influence coefficient of each working parameter through a simulation experiment platform according to the present invention;

[0034] FIG3 is a flow chart of obtaining a preheating time curve and a preheating temperature curve associated with each working parameter through a simulation experiment platform according to the present invention;

[0035] FIG4 is a schematic diagram of a preheating time curve corresponding to an ambient temperature according to the present invention;

[0036] FIG5 is a schematic diagram of a preheating temperature curve corresponding to the ambient temperature of the present invention. DETAILED DESCRIPTION

[0037] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples.

[0038] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in one or more embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0039] As shown in Figures 1 to 5, an engine cold start flexible control strategy includes the following steps:

[0040] Step S101, obtaining the current engine operating parameters, and sorting the operating parameters in descending order according to the influence coefficient of each operating parameter to obtain an operating parameter set;

[0041] The engine's operating parameters include: intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure;

[0042] Step S102: traverse the operating parameter set in descending order of influence coefficients to determine whether each operating parameter is greater than or equal to a preset parameter threshold value of each operating parameter. If any operating parameter is greater than or equal to the corresponding preset parameter threshold value, it indicates that engine preheating is started and the process proceeds to step S103; otherwise, the process returns to step S101.

[0043] Step S103 , obtaining the preheating time and preheating temperature of the engine preheating according to the preheating time curve and preheating temperature curve corresponding to the working parameters that are greater than or equal to the preset parameter threshold.

[0044] In one embodiment of the present invention, as shown in FIG2 , obtaining the influence coefficient of each working parameter through a simulation experiment platform includes the following steps:

[0045] Step S201, selecting one of the operating parameters as an independent variable, the remaining operating parameters as fixed constants, and the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine reaching the rated speed as dependent variables;

[0046] Step S202: Under the first constraint condition of each operating parameter, randomly generate an operating parameter as an independent variable, input the operating parameter as the independent variable and the remaining operating parameters as fixed constants into the simulation experiment platform, and record the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine at the rated speed as dependent variables;

[0047] Step S203, repeating step S202 M times, where M also represents the number of simulation experiments, and obtaining the influence coefficient of the working parameter as the independent variable;

[0048] The calculation formula of the influence coefficient of the working parameter as an independent variable is as follows:

[0049] Where R represents the influence coefficient of the working parameter as the independent variable, M represents the number of simulation experiments, and y i It represents the time it takes for the engine to reach the rated speed in the i-th simulation experiment, in seconds, z irepresents the fuel consumption value of the engine reaching the rated speed in the i-th simulation experiment, in milliliters, α and β represent the first weight parameter and the second weight parameter respectively, the sum of the first weight parameter and the first weight parameter is 1, b1 and b2 represent the first bias parameter and the second bias parameter respectively, the sum of the first bias parameter and the second bias parameter is 1;

[0050] Step S204 , repeating steps S201 to S203 to obtain the influence coefficients of the remaining working parameters respectively.

[0051] In one embodiment of the present invention, the first constraint condition of the operating parameters includes: the randomly generated upper and lower limits of the intake temperature, the randomly generated upper and lower limits of the ambient temperature, and the randomly generated upper and lower limits of the cooling water temperature, which correspond to 0 degrees Celsius and the lower limit of the engine operating temperature, respectively; the randomly generated upper and lower limits of the atmospheric pressure are both custom parameters. Preferably, the upper limit of the randomly generated atmospheric pressure is set to 120 kPa, and the lower limit of the randomly generated atmospheric pressure is set to 60 kPa.

[0052] For example, the upper and lower limits of the randomly generated intake air temperature are 0 degrees Celsius and -40 degrees Celsius respectively.

[0053] In one embodiment of the present invention, the number M of simulation experiments is a custom parameter and is a positive integer greater than 1. Preferably, M is set to 100.

[0054] In one embodiment of the present invention, the first weight parameter, the second weight parameter, the first bias parameter and the second bias parameter are all custom parameters and are real numbers greater than 0 and less than 1. Preferably, the first weight parameter and the second weight parameter are set to 0.5 respectively, and the first bias parameter and the second bias parameter are set to 0.5 respectively.

[0055] It should be noted that, the larger the value of the influence coefficient of the working parameter, the greater the influence of the working parameter on the engine cold start; the first weight parameter represents the user's concern about the engine cold start speed, and the larger the value of the first weight parameter, the greater the user's concern about the engine cold start speed; the second weight parameter represents the user's concern about the fuel consumption during the engine cold start, and the larger the value of the second weight parameter, the greater the user's concern about the fuel consumption during the engine cold start; the role of the first bias parameter and the second bias parameter is to prevent the denominator of the calculation formula of the influence coefficient of the working parameter as the independent variable from being 0. Similarly, the first bias parameter can also be understood as the user's concern about the engine cold start speed. The smaller the value of the first bias parameter, the greater the user's concern about the engine cold start speed. The second bias parameter can also be understood as the user's concern about the fuel consumption during the engine cold start, and the smaller the value of the second bias parameter, the greater the user's concern about the fuel consumption during the engine cold start.

[0056] In one embodiment of the present invention, the preset parameter threshold of the intake air temperature, the preset parameter threshold of the ambient temperature, the preset parameter threshold of the cooling water temperature and the preset parameter threshold of the atmospheric pressure are all custom parameters. Preferably, the preset parameter threshold of the intake air temperature, the preset parameter threshold of the ambient temperature and the preset parameter threshold of the cooling water temperature are all set to the lower limit of the engine operating temperature, for example, minus 40 degrees Celsius; the preset parameter threshold of the atmospheric pressure is set to 60 kPa.

[0057] In one embodiment of the present invention, as shown in FIG3 , obtaining a preheating time curve and a preheating temperature curve associated with each working parameter through a simulation experiment platform includes the following steps:

[0058] Step S301, randomly generating N groups of engine operating parameters, engine preheating time and preheating temperature that meet the second constraint condition;

[0059] Step S302: Input the operating parameters, preheating time, and preheating temperature of each group of engines that meet the second constraint into the simulation experiment platform, and record the time it takes for each group of engines to reach the rated speed;

[0060] Step S303: constructing four first 2-tuples and four second 2-tuples based on the engine operating parameters, preheating time, and preheating temperature corresponding to the minimum value of the time it takes for the engine to reach the rated speed. The four first 2-tuples are respectively represented as: {A1, B}, {A2, B}, {A3, B}, {A4, B}; and the four second 2-tuples are respectively represented as: {A1, C}, {A2, C}, {A3, C}, {A4, C}, where A1, A2, A3, and A4 represent the intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure, B represents the preheating time for engine preheating, and C represents the preheating temperature for engine preheating.

[0061] Step S304 , repeating steps S301 to S303 , constructing a preheating time curve of each operating parameter by least squares fitting based on the first binary group, and constructing a preheating temperature curve of each operating parameter by least squares fitting based on the second binary group.

[0062] In one embodiment of the present invention, N is a custom parameter. Preferably, N is set to 100.

[0063] In one embodiment of the present invention, in addition to the first constraint, the second constraint also includes: the upper limit and lower limit of the preheating time of the engine preheating are both custom parameters, for example, the upper limit and lower limit of the preheating time are set to 1 minute and 10 minutes respectively; the upper limit and lower limit of the preheating temperature of the engine preheating are both custom parameters; for example, the upper limit and lower limit of the preheating temperature are set to the upper limit and lower limit of the engine operating temperature respectively.

[0064] In one embodiment of the present invention, the preheating duration and preheating temperature of the engine are controlled by an electromagnetic time relay.

[0065] As shown in FIG4 , a preheating time curve corresponding to the ambient temperature is shown, wherein the horizontal axis represents the ambient temperature and the vertical axis represents the preheating time.

[0066] As shown in FIG5 , it shows a preheating temperature curve corresponding to the ambient temperature, wherein the abscissa represents the ambient temperature and the ordinate represents the preheating temperature.

[0067] In one embodiment of the present invention, the operating parameters of the engine at the current time can also be input into the multi-layer perceptron as input parameters. The values ​​output by the multi-layer perceptron respectively represent the preheating time and preheating temperature of the engine preheating. The true value of the training sample of the multi-layer perceptron can also be obtained using the above-mentioned simulation experiment, and the cross entropy function is specified as the loss function. The weight parameters of the multi-layer perceptron are updated through back propagation. The training of the multi-layer perceptron is a conventional technical means and will not be elaborated here.

[0068] The above describes the embodiments of this embodiment, but this embodiment is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. An engine cold start flexible control strategy, characterized in that: The following steps are involved: Step S101, obtaining the current engine operating parameters, and sorting the operating parameters in descending order according to the influence coefficient of each operating parameter to obtain an operating parameter set; The engine's operating parameters include: intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure; Step S102: traverse the operating parameter set in descending order of influence coefficients to determine whether each operating parameter is greater than or equal to a preset parameter threshold value of each operating parameter. If any operating parameter is greater than or equal to the corresponding preset parameter threshold value, it indicates that engine preheating is started and the process proceeds to step S103; otherwise, the process returns to step S101. Step S103 , obtaining the preheating time and preheating temperature of the engine preheating according to the preheating time curve and preheating temperature curve corresponding to the working parameters that are greater than or equal to the preset parameter threshold.

2. The engine cold start flexible control strategy according to claim 1, characterized in that: The influence coefficient of each working parameter is obtained through the simulation experiment platform, including the following steps: Step S201, selecting one of the operating parameters as an independent variable, the remaining operating parameters as fixed constants, and the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine reaching the rated speed as dependent variables; Step S202: Under the first constraint condition of each operating parameter, randomly generate an operating parameter as an independent variable, input the operating parameter as the independent variable and the remaining operating parameters as fixed constants into the simulation experiment platform, and record the time it takes for the engine to reach the rated speed and the fuel consumption value of the engine at the rated speed as dependent variables; Step S203, repeating step S202 M times, where M also represents the number of simulation experiments, and obtaining the influence coefficient of the working parameter as the independent variable; The calculation formula of the influence coefficient of the working parameter as an independent variable is as follows: Where R represents the influence coefficient of the working parameter as the independent variable, M represents the number of simulation experiments, and y i Indicates the launch of the i-th simulation experiment The time it takes for the machine to reach the rated speed, in seconds, z i represents the fuel consumption value of the engine reaching the rated speed in the i-th simulation experiment, in milliliters, α and β represent the first weight parameter and the second weight parameter respectively, the sum of the first weight parameter and the first weight parameter is 1, b1 and b2 represent the first bias parameter and the second bias parameter respectively, the sum of the first bias parameter and the second bias parameter is 1; Step S204 , repeating steps S201 to S203 to obtain the influence coefficients of the remaining working parameters respectively.

3. The engine cold start flexible control strategy according to claim 2, characterized in that: The first constraint condition of the operating parameters includes: the randomly generated upper and lower limits of the intake air temperature, the randomly generated upper and lower limits of the ambient temperature, and the randomly generated upper and lower limits of the cooling water temperature, which correspond to 0 degrees Celsius and the lower limit of the engine operating temperature respectively; the randomly generated upper and lower limits of the atmospheric pressure are both custom parameters.

4. The engine cold start flexible control strategy according to claim 2, characterized in that: The number of simulation experiments M is a custom parameter and is a positive integer greater than 1.

5. The engine cold start flexible control strategy according to claim 2, characterized in that: The first weight parameter, the second weight parameter, the first bias parameter, and the second bias parameter are all custom parameters and are real numbers greater than 0 and less than 1.

6. The engine cold start flexible control strategy according to claim 1, characterized in that: The preset parameter thresholds for the intake air temperature, the ambient temperature, the cooling water temperature, and the atmospheric pressure are all user-defined parameters.

7. The engine cold start flexible control strategy according to claim 1, characterized in that: Obtaining the preheating time curve and preheating temperature curve associated with each working parameter through the simulation experiment platform includes the following steps: Step S301, randomly generating N groups of engine operating parameters, engine preheating time and preheating temperature that meet the second constraint condition; Step S302: Input the operating parameters, preheating time and preheating temperature of each group of engines that meet the second constraint condition into the simulation experiment platform, and record the number of times each group of engines reaches the target temperature. Time to reach rated speed; Step S303: constructing four first 2-tuples and four second 2-tuples based on the engine operating parameters, preheating time, and preheating temperature corresponding to the minimum value of the time it takes for the engine to reach the rated speed. The four first 2-tuples are respectively represented as: {A1, B}, {A2, B}, {A3, B}, {A4, B}; and the four second 2-tuples are respectively represented as: {A1, C}, {A2, C}, {A3, C}, {A4, C}, where A1, A2, A3, and A4 represent the intake air temperature, ambient temperature, cooling water temperature, and atmospheric pressure, B represents the preheating time for engine preheating, and C represents the preheating temperature for engine preheating. Step S304 , repeating steps S301 to S303 , constructing a preheating time curve of each operating parameter by least squares fitting based on the first binary group, and constructing a preheating temperature curve of each operating parameter by least squares fitting based on the second binary group.

8. The engine cold start flexible control strategy according to claim 7, characterized in that: N is a custom parameter.

9. The engine cold start flexible control strategy according to claim 3, characterized in that: In addition to the first constraint, the second constraint further includes: the upper limit and lower limit of the engine preheating time are both custom parameters.

10. The engine cold start flexible control strategy according to claim 1, characterized in that: The engine preheating time and preheating temperature are controlled by an electromagnetic time relay.

Images