Engine warm-up control method, control device, and vehicle engine

Abstract

The present invention discloses a warm-up control method for an engine. The method includes, when the engine enters the cold start mode, calculating the current heat generation of the engine, the heat rise required for the engine to increase from the current water temperature to the target water temperature, and the change in heat dissipation, summing the current heat generation of the engine, the heat rise, and the change in heat dissipation to obtain the target total heat generation of the engine, obtaining the target compression ratio according to the target total heat generation of the engine and a preset second corresponding relationship, and finally determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to operate at the warm-up target compression ratio. By controlling the compression ratio of the engine, the compression temperature at the time of engine ignition is adjusted, thereby improving the combustion efficiency and combustion temperature, so that the variable compression ratio engine can achieve the purpose of rapid warm-up without relying on electronic devices such as an electronic water pump and an electronic thermostat. The present invention also provides a control device and an automotive engine.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a warm-up control method for an engine, a control device, and an automotive engine. Background Art

[0002] The variable compression ratio technology is a revolutionary technology for engines, which can balance the fuel economy and power performance of the engine, that is, while reducing the fuel consumption of the engine, the power torque of the engine can be increased. Currently, in the traditional mechanically controlled cooling system, due to the inability of the mechanical thermostat and mechanical water pump to intelligently control the opening degree of the thermostat and the flow rate of the water pump, the warm-up speed and temperature response of the engine are slow, and rapid warm-up cannot be achieved. There are already cooling systems that use electronic control such as electronic thermostats, electronic water pumps, and temperature control modules to quickly adjust the water temperature, so as to achieve the purpose of rapid warm-up of the engine and adjust the water temperature to the optimal temperature under different engine operating conditions. However, the above-mentioned electronic devices are relatively expensive. Summary of the Invention

[0003] Multiple aspects of the embodiments of the present invention provide a warm-up control method for an engine, a control device, and an automotive engine, which can solve the problem that the existing variable compression ratio engine needs to rely on expensive electronic devices such as electronic water pumps and electronic thermostats to achieve rapid warm-up.

[0004] The first aspect of the embodiment of the present invention provides a warm-up control method for an engine, including:

[0005] When the engine enters the cold start mode, according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first corresponding relationship, obtain the current engine heat generation; wherein, the first corresponding relationship is used to indicate the corresponding relationship between the engine speed, the engine load, the engine compression ratio, and the engine heat generation;

[0006] Calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine;

[0007] Calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine;

[0008] Sum the current engine heat generation, the temperature rise heat, and the heat dissipation change amount to obtain the target total heat generation of the engine;

[0009] According to the target total heat generation of the engine and a preset second corresponding relationship, obtain the target compression ratio; wherein, the second corresponding relationship is used to indicate the corresponding relationship between the target total heat generation of the engine and the target compression ratio;

[0010] Determine the warm-up target compression ratio according to the target compression ratio, and control the engine to operate at the warm-up target compression ratio.

[0011] Preferably, the step of determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to operate at the warm-up target compression ratio specifically includes:

[0012] When the target compression ratio is less than the maximum compression ratio of the engine, use the target compression ratio as the warm-up target compression ratio of the engine, and control the engine to operate at the warm-up target compression ratio;

[0013] When the target compression ratio is greater than the maximum compression ratio of the engine, obtain the optimal compression ratio according to the third corresponding relationship between the total target heat generation of the engine and the preset; wherein, the third corresponding relationship is used to indicate the corresponding relationship between the total target heat generation of the engine and the optimal compression ratio;

[0014] Use the optimal compression ratio as the warm-up target compression ratio of the engine, and control the engine to operate at the warm-up target compression ratio.

[0015] Preferably, after the step of determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to operate at the warm-up target compression ratio, it further includes:

[0016] Obtain the current water temperature of the engine every preset interval period, and calculate the water temperature fluctuation amount of the engine within the preset interval period;

[0017] When the current water temperature is less than the cold start threshold, return to the step of obtaining the current engine heat generation according to the current engine speed, current engine load, current engine compression ratio and the preset first corresponding relationship when the engine enters the cold start mode;

[0018] When the current water temperature is greater than the maximum water temperature threshold, control the engine to alarm and limit the speed and torque, and request the engine to stop;

[0019] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is less than the first temperature threshold, control the engine to switch from the cold start mode to the normal mode;

[0020] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is greater than the first temperature threshold, monitor the water temperature fluctuation amount in the next preset interval period;

[0021] When it is detected that the water temperature fluctuation amount in the next preset interval period is less than the first temperature threshold, record the engine distortion, and control the engine to switch from the cold start mode to the normal mode;

[0022] When it is detected that the water temperature fluctuation amount within the next preset interval period is greater than the first temperature threshold, control the engine to give an alarm, limit the speed and torque, and request the engine to shut down.

[0023] Preferably, calculating the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine specifically includes:

[0024] Determine the current coolant flow rate according to the current water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship, where the preset fourth corresponding relationship is used to indicate the relationship between the engine water temperature, the engine speed, and the coolant flow rate;

[0025] Determine the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current water temperature and the current coolant flow rate;

[0026] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the current water temperature;

[0027] Determine the target coolant flow rate according to the target water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship;

[0028] Determine the basic heat dissipation amount of the engine corresponding to the target water temperature according to the target water temperature and the target coolant flow rate;

[0029] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation amount of the engine corresponding to the target water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the target water temperature;

[0030] Take the difference between the heat dissipation amount of the engine corresponding to the target water temperature and the heat dissipation amount of the engine corresponding to the current water temperature as the engine heat dissipation change amount.

[0031] Preferably, before obtaining the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first corresponding relationship when the engine enters the cold start mode, it further includes:

[0032] When it is detected that the vehicle is powered on, if a compression ratio sensor fault code is received, control the engine to give an alarm and control the engine to enter the first fault mode;

[0033] When the engine enters the first fault mode, obtain the locking function information of the variable compression ratio mechanism. When the locking function information is equal to 1, control the engine to operate according to the overall machine Map at the locked state compression ratio;

[0034] When the lock function information is equal to 0, control the engine to limit speed and torque, and request the engine to shut down.

[0035] Preferably, before obtaining the current engine calorific value according to the current engine speed, the current engine load, the current engine compression ratio and a preset first correspondence relationship when the engine enters the cold start mode, it further includes:

[0036] When it is detected that the vehicle is powered on, if a compression ratio execution motor fault code or an oil pump fault code is received, control the engine to alarm and control the engine to enter the second fault mode;

[0037] When the engine enters the second fault mode, obtain the lock function information of the variable compression ratio mechanism. When the lock function information is equal to 1, control the engine to operate according to the overall machine Map at the locked state compression ratio;

[0038] When the lock function information is equal to 0, control the engine to limit speed and torque, and request the engine to shut down.

[0039] Preferably, before obtaining the current engine calorific value according to the current engine speed, the current engine load, the current engine compression ratio and a preset first correspondence relationship when the engine enters the cold start mode, it further includes:

[0040] When it is detected that the vehicle is powered on, if a water temperature sensor fault code is received, control the engine to alarm and limit speed and torque, and request the engine to shut down.

[0041] Preferably, before obtaining the current engine calorific value according to the current engine speed, the current engine load, the current engine compression ratio and a preset first correspondence relationship when the engine enters the cold start mode, it further includes:

[0042] When it is detected that the current water temperature of the engine is lower than the cold start threshold, control the engine to enter the cold start mode;

[0043] When it is detected that the current water temperature of the engine is higher than the cold start threshold, control the engine to enter the normal working mode.

[0044] A control device is correspondingly provided in the second aspect of the embodiments of the present invention, including:

[0045] A calorific value acquisition module, configured to obtain the current engine calorific value according to the current engine speed, the current engine load, the current engine compression ratio and a preset first correspondence relationship when the engine enters the cold start mode; wherein, the first correspondence relationship is used to indicate the correspondence relationship between the engine speed, the engine load, the engine compression ratio and the engine calorific value;

[0046] The temperature rise heat calculation module is used to calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine;

[0047] The heat dissipation change amount calculation module is used to calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine;

[0048] The target total heat generation amount calculation module is used to sum the current engine heat generation amount, the temperature rise heat, and the heat dissipation change amount to obtain the target total heat generation amount of the engine;

[0049] The target compression ratio acquisition module is used to obtain the target compression ratio according to the target total heat generation amount of the engine and a preset second corresponding relationship; wherein, the second corresponding relationship is used to indicate the corresponding relationship between the target total heat generation amount of the engine and the target compression ratio;

[0050] The warm-up control module is used to determine the warm-up target compression ratio according to the target compression ratio and control the engine to work at the warm-up target compression ratio.

[0051] The third aspect of the embodiments of the present invention provides an automobile engine, and the engine includes the control device described in the above embodiments.

[0052] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: The embodiments of the present invention provide a warm-up control method for an engine. The method includes calculating the current engine heat generation amount, the temperature rise heat required for the engine to rise from the current water temperature to the target water temperature, and the heat dissipation change amount from the current water temperature to the target water temperature when the engine enters the cold start mode, summing the current engine heat generation amount, the temperature rise heat, and the heat dissipation change amount to obtain the target total heat generation amount of the engine, obtaining the target compression ratio according to the target total heat generation amount of the engine and a preset second corresponding relationship, and finally determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to work at the warm-up target compression ratio. By controlling the compression ratio of the engine, the compression temperature at the time of engine ignition is adjusted, thereby improving the combustion efficiency and combustion temperature, so that the variable compression ratio engine can achieve the purpose of rapid warm-up without increasing costs without relying on expensive electronic devices such as an electronic water pump and an electronic thermostat. At the same time, the embodiments of the present invention also correspondingly provide a control device and an automobile engine. Description of the Drawings

[0053] Figure 1 is a schematic flowchart of an embodiment of the warm-up control method for the engine provided by the present invention;

[0054] Figure 2 is a schematic flowchart of another embodiment of the warm-up control method for the engine provided by the present invention;

[0055] Figure 3 It is a structural block diagram of the control device provided by the present invention. Specific embodiments

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0057] Based on the cooling system of a traditional mechanical thermostat and a mechanical water pump, the working state of the thermostat is only related to the water temperature. When the water temperature has not reached the opening temperature, it can be considered that the engine is in the warm-up process. At this time, the engine generally operates at a low load, and the heat generated by the engine is generally low. At the same time, since the flow rate of the mechanical water pump is mainly related to the engine speed, the coolant flow rate has basically been determined, and it is impossible to actively control the engine coolant flow rate like an electronic water pump, such as reducing the coolant flow rate, thereby reducing the engine heat dissipation and then realizing rapid warm-up. Therefore, for the cooling system controlled by traditional machinery, the engine warm-up is relatively slow.

[0058] The variable compression ratio technology is a revolutionary technology for engines. The compression ratio is one of the most critical parameters for improving the combustion efficiency of engines. At the same time, a high compression ratio can increase the cylinder temperature at ignition, improve the combustion stability during cold start, and make the combustion more complete. The variable compression ratio engine can alleviate the problem of too slow warm-up rate through corresponding control methods. Therefore, the embodiments of the present invention propose a warm-up control method for an engine without increasing costs (such as upgrading the electronic thermostat and the electronic water pump).

[0059] See Figure 1 , which is a schematic flow chart of an embodiment of the warm-up control method for an engine provided by the present invention. The warm-up control method for an engine provided by the embodiments of the present invention is applicable to a variable compression ratio engine and includes steps S11 to S16:

[0060] Step S11, when the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence; wherein, the first correspondence is used to indicate the correspondence between the engine speed, the engine load, the engine compression ratio, and the engine heat generation;

[0061] Step S12, calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine;

[0062] Step S13, calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine;

[0063] Step S14, sum up the current engine heat generation amount, the heat amount of temperature rise, and the heat dissipation change amount to obtain the target total engine heat generation amount;

[0064] Step S15, obtain the target compression ratio according to the target total engine heat generation amount and a preset second corresponding relationship; wherein, the second corresponding relationship is used to indicate the corresponding relationship between the target total engine heat generation amount and the target compression ratio;

[0065] Step S16, determine the warm-up target compression ratio according to the target compression ratio, and control the engine to operate at the warm-up target compression ratio.

[0066] It should be noted that in the specific implementation of the embodiments of the present invention, step S13 can be executed first, and then step S12, or step S12 and step S13 can be executed simultaneously. In addition, it can be understood that the water temperature in the embodiments of the present invention actually refers to the water temperature of the engine coolant, and step S12, "calculate the heat amount of temperature rise required to raise the current water temperature of the engine to the target water temperature of the engine", should be understood as the heat that the engine coolant needs to absorb when rising from the current water temperature to the target water temperature.

[0067] The warm-up control method for an engine provided by the embodiments of the present invention includes, when the engine enters the cold start mode, calculating the current engine heat generation amount, the heat amount of temperature rise required for the engine to rise from the current water temperature to the target water temperature, and the heat dissipation change amount from the current water temperature to the target water temperature, summing up the current engine heat generation amount, the heat amount of temperature rise, and the heat dissipation change amount to obtain the target total engine heat generation amount, obtaining the target compression ratio according to the target total engine heat generation amount and a preset second corresponding relationship, and finally determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to operate at the warm-up target compression ratio. By controlling the compression ratio of the engine, the compression temperature at the time of engine ignition is adjusted, thereby improving the combustion efficiency and combustion temperature, so that the variable compression ratio engine can achieve the purpose of rapid warm-up without increasing costs without relying on expensive electronic devices such as an electronic water pump and an electronic thermostat.

[0068] In an alternative embodiment, before step S11, "when the engine enters the cold start mode, obtain the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first corresponding relationship", further includes:

[0069] When it is detected that the vehicle is powered on, if a compression ratio sensor fault code is received, control the engine to give an alarm, and control the engine to enter the first fault mode;

[0070] When the engine enters the first fault mode, obtain the locking function information of the variable compression ratio mechanism. When the locking function information is equal to 1, control the engine to operate according to the overall engine Map at the locked compression ratio.

[0071] When the locking function information is equal to 0, control the engine to limit speed and torque, and request the engine to shut down.

[0072] In specific implementation, a compression ratio sensor can be installed on the variable compression ratio engine so that the engine ECU can collect the compression ratio of the engine through the compression ratio sensor. To avoid component losses and safety accidents caused by related faults in the engine system, in the embodiment of the present invention, after detecting that the vehicle is powered on, the ECU collects the current compression ratio of the engine and determines whether the value of the current compression ratio of the engine is normal. If any one of the maximum fault, minimum fault, and unreasonable signal fault occurs in the compression ratio sensor, the engine cannot judge the current compression ratio situation of the engine through the compression ratio sensor. At this time, the ECU will receive the compression ratio sensor fault code, and after receiving the compression ratio sensor fault code, control the engine to alarm and control the engine to enter the first fault mode.

[0073] When the engine enters the first fault mode, since the engine cannot determine the current compression ratio, parameters such as engine fuel injection and ignition, and timing phase cannot be obtained according to the corresponding Map, which may lead to engine damage and even cause safety accidents. To avoid the above situation, the ECU judges according to whether the variable compression ratio mechanism has a physical locking function F_lock. F_lock = 1 represents having a physical locking function, and F_lock = 0 is vice versa. The physical locking function F_lock has been assigned when the variable compression ratio mechanism is developed. When the compression ratio sensor or the actuator cannot work properly, the variable compression ratio mechanism can be locked under the physical locking function to obtain a fixed locked compression ratio value. When the locking function information obtained by the ECU is F_lock = 1, the engine can still operate according to the overall engine Map at the locked compression ratio l and continue to work; if the locking function information obtained by the ECU is F_lock = 0, the ECU controls the engine to limit speed and torque through parameters such as fuel injection and ignition, and timing phase, and requests the engine to shut down. Among them, Map l is a preset value calibrated by the engine through tests, referring to the overall engine Map when the engine enters the first fault mode and the second fault mode.

[0074] In an alternative embodiment, before the step S11 "when the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence relationship", the method further includes:

[0075] When it is detected that the vehicle is powered on, if a compression ratio actuator motor fault code or an oil pump fault code is received, control the engine to give an alarm, and control the engine to enter a second fault mode;

[0076] When the engine enters the second fault mode, obtain the locking function information of the variable compression ratio mechanism. When the locking function information is equal to 1, control the engine to operate according to the overall engine Map at the locked compression ratio;

[0077] When the locking function information is equal to 0, control the engine to limit speed and torque, and request the engine to stop.

[0078] In specific implementation, each time the ECU is powered on, it collects information on the compression ratio actuator motor or the electronic oil pump, and determines whether the compression ratio actuator is normal. If the compression ratio actuator has any one of the following faults: hardware damage, inability to be powered on, unreasonable signal, etc., the compression ratio actuator cannot receive the execution command feedback from the ECU to perform compression ratio holding and switching actions. Therefore, the compression ratio actuator will send a compression ratio actuator motor fault code to the ECU, and the ECU will control the engine to give an alarm and control the engine to enter the second fault mode after receiving the compression ratio actuator motor fault code.

[0079] When the engine is in the second fault mode, the engine can determine the current compression ratio. However, since the compression ratio actuator cannot work properly at this time and cannot respond to the command to adjust the engine compression ratio, at this time, parameters such as engine fuel injection and ignition, and timing phase can only be sampled according to the overall engine Map at the original compression ratio, which may lead to the engine being unable to provide sufficient torque output and even cause safety accidents. To avoid the above situation, the ECU judges according to the locking function information F_lock. When the locking function information F_lock = 1, the engine can still operate according to the overall engine Map at the locked compression ratio l and continue to work; if the locking function information F_lock = 0, the ECU controls the engine to limit speed and torque through parameters such as fuel injection and ignition, and timing phase, and requests the engine to stop.

[0080] In an alternative embodiment, before the step S11 "when the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence relationship", the method further includes:

[0081] When it is detected that the vehicle is powered on, if a fault code of the water temperature sensor is received, control the engine to alarm, limit speed and torque, and request the engine to shut down.

[0082] It can be understood that when the compression ratio sensor, the compression ratio actuator, and the water temperature sensor fail, through the adjustment of the above steps, the present invention can avoid further damage to engine parts and potential safety accidents of the vehicle and personnel.

[0083] In an optional implementation manner, before the step S11 "when the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence relationship", it further includes:

[0084] When it is detected that the current water temperature of the engine is lower than the cold start threshold, control the engine to enter the cold start mode;

[0085] When it is detected that the current water temperature of the engine is higher than the cold start threshold, control the engine to enter the normal working mode.

[0086] In specific implementation, the cold start threshold is a preset value, which can refer to the opening temperature of the thermostat, for example, set within the range of 83°C to 93°C. It is specifically set according to the actual working conditions, and the embodiments of the present invention do not make limitations.

[0087] In the embodiment of the present invention, in the specific implementation of the step S11 "when the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence relationship", a mapping relationship table of the first correspondence relationship can be pre-configured, and the engine compression ratio ε can be determined by looking up the table. Exemplarily, the mapping relationship table of the first correspondence relationship can be in the following form:

[0088]

[0089] Among them, Q in is the engine heat generation, n is the engine speed, b is the engine load, and ε is the engine compression ratio.

[0090] In the embodiment of the present invention, in the specific implementation of the step S12 "calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine", the current water temperature T and the target water temperature T of the engine can be calculated first t , and the water temperature evaluation parameter △T is calculated through the formula △T = T - T t , and then the temperature rise heat Q required for the engine coolant to raise the water temperature by △T is calculated need .

[0091] In an alternative embodiment, step S13, "calculating the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine", specifically includes:

[0092] Determine the current coolant flow rate according to the current water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship, where the preset fourth corresponding relationship is used to indicate the relationship between the engine water temperature, the engine speed, and the coolant flow rate;

[0093] Determine the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current water temperature and the current coolant flow rate;

[0094] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the current water temperature;

[0095] Determine the target coolant flow rate according to the target water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship;

[0096] Determine the basic heat dissipation amount of the engine corresponding to the target water temperature according to the target water temperature and the target coolant flow rate;

[0097] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation amount of the engine corresponding to the target water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the target water temperature;

[0098] Take the difference between the heat dissipation amount of the engine corresponding to the target water temperature and the heat dissipation amount of the engine corresponding to the current water temperature as the engine heat dissipation change amount.

[0099] In specific implementation, the preset fourth corresponding relationship may be in the following tabular form:

[0100]

[0101] It can be understood that since the coolant flow rate q and the thermostat opening are strongly correlated with the engine speed n and the current water temperature T respectively, the coolant flow rate q can be obtained through the current water temperature T, the engine speed n, and the fourth corresponding relationship. At the same time, in the cold start mode, since the thermostat has not been opened and the engine coolant is in a small cycle and has not entered the large cycle, the heat of the engine is released by air convection heat dissipation. At this time, the engine heat dissipation amount Q out is very small and is mainly related to the engine block temperature, the ambient temperature T h and the vehicle speed V. And the block temperature is related to the engine coolant flow rate q and the water temperature T. Therefore, the basic heat dissipation amount Q of the engine at normal temperature can be obtained through a large amount of test dataout_b = f(T, q), and is corrected by the ambient temperature T h and the vehicle speed V to obtain the heat dissipation Q corresponding to the current water temperature out , and the heat dissipation corresponding to the target water temperature is calculated in the same way. Then, by subtracting the heat dissipation corresponding to the current water temperature from the heat dissipation corresponding to the target water temperature, the engine heat dissipation change ΔQ out is obtained, so as to calculate the temperature rise heat Q need , the current engine heat generation Q in and the heat dissipation change ΔQ out to sum up to obtain the target total engine heat generation Q in_all , and then using the preset second correspondence relationship, the target compression ratio ε t is obtained.

[0102] In specific implementation, the mapping relationship table between the target total engine heat generation Q in_all and the target compression ratio ε t can be pre-configured according to the second correspondence relationship, and the target compression ratio ε t is determined by looking up the table. Exemplarily, a mapping relationship table containing only the target total engine heat generation Q in_all and the target compression ratio ε t can be pre-configured according to the second correspondence relationship to determine the target compression ratio ε t . In addition, the mapping relationship table of the first correspondence relationship can also be directly used, and the target total engine heat generation Q in_all is used as the engine heat generation Q in , and at the same time, the target compression ratio ε t is used as the engine compression ratio ε. In specific applications, the corresponding relationship between the engine heat generation Q in and the engine compression ratio ε in the table is queried to determine the target compression ratio ε t . Exemplarily, the second correspondence relationship can be in the following form:

[0103]

[0104] It can be understood that in order to make the target compression ratio ε t work within the appropriate working range, it is necessary to judge the target compression ratio ε t to avoid the target compression ratio ε t being higher than the maximum compression ratio ε maxIn the case of directly controlling the engine to operate at the target compression ratio, abnormal ignition conditions such as detonation may occur, as well as problems that may damage the service life of the engine. Therefore, it is necessary to further determine the final warm-up target compression ratio according to the specific situation based on the target compression ratio. Furthermore, in an alternative embodiment, the step S16 "determine the warm-up target compression ratio according to the target compression ratio and control the engine to operate at the warm-up target compression ratio" specifically includes:

[0105] When the target compression ratio is less than the maximum compression ratio of the engine, use the target compression ratio as the warm-up target compression ratio of the engine and control the engine to operate at the warm-up target compression ratio;

[0106] When the target compression ratio is greater than the maximum compression ratio of the engine, obtain the optimal compression ratio according to the total target heat generation of the engine and a preset third correspondence relationship; wherein, the third correspondence relationship is used to indicate the correspondence relationship between the total target heat generation of the engine and the optimal compression ratio;

[0107] Use the optimal compression ratio as the warm-up target compression ratio of the engine and control the engine to operate at the warm-up target compression ratio.

[0108] In the embodiment of the present invention, compare the target compression ratio ε t with the maximum compression ratio ε max of the engine, and when ε t <ε max , adjust the compression ratio of the engine to ε t , and when ε t >ε max , obtain the optimal compression ratio ε b within the threshold range through the third correspondence relationship, and control the engine to operate at the optimal compression ratio ε b . Furthermore, by adjusting the compression ratio of the engine, control the water temperature of the coolant of the traditional mechanical control cooling system to rise rapidly, thereby improving the warm-up efficiency of the engine.

[0109] In an alternative embodiment, after the step S16 "determine the warm-up target compression ratio according to the target compression ratio and control the engine to operate at the warm-up target compression ratio", it further includes:

[0110] Obtain the current water temperature of the engine every preset interval period and calculate the water temperature fluctuation amount of the engine within the preset interval period;

[0111] When the current water temperature is less than the cold start threshold, return to the step of obtaining the current engine heat generation according to the current engine speed, current engine load, current engine compression ratio and a preset first correspondence relationship when the engine enters the cold start mode;

[0112] When the current water temperature is greater than the maximum water temperature threshold, control the engine to give an alarm and limit the speed and torque, and request the engine to shut down;

[0113] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is less than the first temperature threshold, control the engine to switch from the cold start mode to the normal mode;

[0114] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is greater than the first temperature threshold, monitor the water temperature fluctuation amount within the next preset interval period;

[0115] When it is detected that the water temperature fluctuation amount within the next preset interval period is less than the first temperature threshold, perform an engine distortion record, and control the engine to switch from the cold start mode to the normal mode;

[0116] When it is detected that the water temperature fluctuation amount within the next preset interval period is greater than the first temperature threshold, control the engine to give an alarm and limit the speed and torque, and request the engine to shut down.

[0117] In specific implementation, the current water temperature of the engine can be obtained through a water temperature sensor. The water temperature sensor obtains the water temperature of the engine every preset interval period t and sends it to the ECU, so that the ECU can monitor the water temperature of the engine in each cycle period, and calculate the engine water temperature fluctuation amount △T n+1 =T n+1 -T n where T n+1 is the water temperature of the current cycle period, T n is the water temperature of the previous cycle period. When it is detected that the engine water temperature fluctuation amount △T n+1 exceeds the first temperature threshold T d for two consecutive interval periods, or the current water temperature T exceeds the maximum water temperature threshold T max , control the engine to give an alarm and limit the speed and torque, and request the engine to shut down, thereby limiting the temperature rise speed and the maximum water temperature of the engine, so as to better control the stability of the water temperature.

[0118] Exemplarily, referring to Figure 2 , Figure 2 is a schematic flowchart of another embodiment of the engine warm-up control method provided by the present invention. In this embodiment, the warm-up control method executes steps S1 to S9:

[0119] Step S1: Detect whether the compression ratio sensor is faulty. If so, determine whether the lock function information F_lock is equal to 1. When it is detected that F_lock is equal to 1, control the engine to execute according to the overall machine Map at the compression ratio in the locked state. When it is detected that F_lock is not equal to 1, control the engine to alarm, limit speed and torque, and request the engine to shut down. If the compression ratio sensor is not faulty, execute Step S2;

[0120] Step S2: Determine whether the compression ratio actuator is faulty. If so, determine whether the lock function information F_lock is equal to 1. When it is detected that F_lock is equal to 1, control the engine to execute according to the overall machine Map at the compression ratio in the locked state. When it is detected that F_lock is not equal to 1, control the engine to alarm, limit speed and torque, and request the engine to shut down. If the compression ratio actuator is not faulty, execute Step S3;

[0121] Step S3: Determine whether the water temperature sensor is faulty. If so, control the engine to alarm, limit speed and torque, and request the engine to shut down. Otherwise, execute Step S4;

[0122] Step S4: Determine whether the current water temperature is lower than the cold start threshold. If so, the engine enters the cold start mode and execute Step S5. Otherwise, execute Step S9;

[0123] Step S5: Calculate the total target heat generation Q of the engine in_all , determine the warm-up target compression ratio and execute it;

[0124] Step S6: Determine whether the current water temperature is lower than the cold start threshold. If so, return to Step S5. Otherwise, execute Step S7;

[0125] Step S7: Determine whether the current water temperature exceeds the maximum water temperature threshold. If so, control the engine to alarm, limit speed and torque, and request the engine to shut down. Otherwise, execute Step S8;

[0126] Step S8: Determine whether the water temperature fluctuation amount exceeds the first temperature threshold. If the water temperature fluctuation amount does not exceed the first temperature threshold, execute Step S9. If the water temperature fluctuation amount exceeds the first temperature threshold, further determine whether the water temperature fluctuation amount in the next interval period still exceeds the first temperature threshold. If it still exceeds the first temperature threshold, control the engine to alarm, limit speed and torque, and request the engine to shut down. If the water temperature fluctuation amount in the next interval period does not exceed the first temperature threshold, execute Step S9;

[0127] Step S9: Control the engine to enter the normal working mode.

[0128] See Figure 3 , Figure 3It is a structural block diagram of a control device provided corresponding to an embodiment of the present invention. The control device provided in the embodiment of the present invention includes:

[0129] A calorific value acquisition module 101, configured to obtain the current engine calorific value according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first correspondence relationship when the engine enters the cold start mode; wherein, the first correspondence relationship is used to indicate the correspondence relationship between the engine speed, the engine load, the engine compression ratio, and the engine calorific value;

[0130] A temperature rise heat calculation module 102, configured to calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine;

[0131] A heat dissipation change amount calculation module 103, configured to calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine;

[0132] A target total calorific value calculation module 104, configured to sum the current engine calorific value, the temperature rise heat, and the heat dissipation change amount to obtain the target total calorific value of the engine;

[0133] A target compression ratio acquisition module 105, configured to obtain a target compression ratio according to the target total calorific value of the engine and a preset second correspondence relationship; wherein, the second correspondence relationship is used to indicate the correspondence relationship between the target total calorific value of the engine and the target compression ratio;

[0134] A warm-up control module 106, configured to determine a warm-up target compression ratio according to the target compression ratio and control the engine to operate at the warm-up target compression ratio.

[0135] In an optional implementation manner, the control device further includes:

[0136] A compression ratio sensor fault control module, configured to, when it is detected that the vehicle is powered on and a compression ratio sensor fault code is received, control the engine to give an alarm and control the engine to enter a first fault mode;

[0137] When the engine enters the first fault mode, obtain the locking function information of the variable compression ratio mechanism, and when the locking function information is equal to 1, control the engine to operate according to the overall machine Map at the locked state compression ratio;

[0138] When the locking function information is equal to 0, control the engine to limit speed and torque and request the engine to stop.

[0139] In an optional implementation manner, the control device further includes:

[0140] The compression ratio actuator fault control module is used to control the engine to alarm and enter the second fault mode when it detects that the vehicle is powered on and receives a compression ratio actuator motor fault code or an oil pump fault code.

[0141] When the engine enters the second fault mode, obtain the locking function information of the variable compression ratio mechanism. When the locking function information is equal to 1, control the engine to operate according to the overall machine Map at the locked state compression ratio.

[0142] When the locking function information is equal to 0, control the engine to limit speed and torque, and request the engine to stop.

[0143] In an alternative embodiment, the control device further includes:

[0144] The water temperature sensor fault control module is used to control the engine to alarm, limit speed and torque, and request the engine to stop when it detects that the vehicle is powered on and receives a water temperature sensor fault code.

[0145] In an alternative embodiment, the heat dissipation change amount calculation module 103 is specifically used for:

[0146] Determine the current coolant flow rate according to the current water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship, where the preset fourth corresponding relationship is used to indicate the relationship between the engine water temperature, the engine speed, and the coolant flow rate.

[0147] Determine the basic heat dissipation of the engine corresponding to the current water temperature according to the current water temperature and the current coolant flow rate.

[0148] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation of the engine corresponding to the current water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation of the engine corresponding to the current water temperature.

[0149] Determine the target coolant flow rate according to the target water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship.

[0150] Determine the basic heat dissipation of the engine corresponding to the target water temperature according to the target water temperature and the target coolant flow rate.

[0151] Obtain the current ambient temperature and the current vehicle speed, and correct the basic heat dissipation of the engine corresponding to the target water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation of the engine corresponding to the target water temperature.

[0152] Take the difference between the engine heat dissipation corresponding to the target water temperature and the engine heat dissipation corresponding to the current water temperature as the engine heat dissipation change amount.

[0153] In an alternative embodiment, the warm-up control module 106 is specifically configured to:

[0154] When the target compression ratio is less than the maximum compression ratio of the engine, take the target compression ratio as the warm-up target compression ratio of the engine, and control the engine to operate at the warm-up target compression ratio;

[0155] When the target compression ratio is greater than the maximum compression ratio of the engine, obtain the optimal compression ratio according to the total target heat generation of the engine and a preset third correspondence; wherein, the third correspondence is used to indicate the correspondence between the total target heat generation of the engine and the optimal compression ratio;

[0156] Take the optimal compression ratio as the warm-up target compression ratio of the engine, and control the engine to operate at the warm-up target compression ratio.

[0157] In an alternative embodiment, the control device further includes a water temperature detection and control module, and the water temperature detection and control module is used for:

[0158] Obtain the current water temperature of the engine every preset interval period, and calculate the water temperature fluctuation amount of the engine within the preset interval period;

[0159] When the current water temperature is less than the cold start threshold, return to the step of obtaining the current engine heat generation according to the current engine speed, current engine load, current engine compression ratio and a preset first correspondence when the engine enters the cold start mode;

[0160] When the current water temperature is greater than the maximum water temperature threshold, control the engine to give an alarm and limit the speed and torque, and request the engine to stop;

[0161] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is less than the first temperature threshold, control the engine to switch from the cold start mode to the normal mode;

[0162] When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is greater than the first temperature threshold, monitor the water temperature fluctuation amount in the next preset interval period;

[0163] When it is detected that the water temperature fluctuation amount in the next preset interval period is less than the first temperature threshold, record the engine distortion, and control the engine to switch from the cold start mode to the normal mode;

[0164] When it is detected that the water temperature fluctuation amount within the next preset interval period is greater than the first temperature threshold, control the engine to give an alarm, limit the speed and torque, and request the engine to stop.

[0165] It should be noted that the control device provided in the embodiment of the present invention is used to execute all the process steps of the engine warm-up control method in the above embodiment, and the working principles and beneficial effects of the two correspond one by one, so they will not be elaborated here.

[0166] In addition, the control device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the attached drawings of the control device embodiment provided by the present invention, the connection relationship between the modules indicates that they have a communication connection, which can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement it without creative work.

[0167] Preferably, all modules are integrated in the engine ECU.

[0168] Correspondingly, another embodiment of the present invention further provides an automotive engine, and the automotive engine includes the control device provided in the above embodiment.

[0169] In summary, the embodiments of the present invention provide a warm-up control method for an engine, a control device, and an automotive engine. The method includes calculating the current engine heat generation, the heat rise required for the engine to increase from the current water temperature to the target water temperature, and the heat dissipation change from the current water temperature to the target water temperature when the engine enters the cold start mode, summing the current engine heat generation, the heat rise, and the heat dissipation change to obtain the target total engine heat generation, obtaining the target compression ratio according to the target total engine heat generation and a preset second corresponding relationship, and finally determining the warm-up target compression ratio based on the target compression ratio and controlling the engine to operate at the warm-up target compression ratio. By controlling the compression ratio of the engine, the compression temperature at the time of engine ignition is adjusted, thereby improving the combustion efficiency and combustion temperature, enabling the variable compression ratio engine to achieve the purpose of rapid warm-up without relying on expensive electronic devices such as an electronic water pump and an electronic thermostat without increasing costs. In addition, the control method provided by the embodiments of the present invention monitors the water temperature and the water temperature fluctuation amount, and then limits the engine heat rise speed and the maximum water temperature, and controls the stability of the water temperature by adjusting working parameters such as the compression ratio. Further, when a failure occurs in the compression ratio sensor, the compression ratio actuator, or the water temperature sensor, the control method of the embodiments of the present invention obtains the lock function information of the engine, and when the obtained lock function information is 1, controls the engine to operate according to the whole engine Map at the locked state compression ratio, and when the obtained lock function information is 0, controls the engine to alarm and limit the speed and torque to avoid damage to engine parts and even safety accidents of the whole vehicle and personnel caused by the above-mentioned faults. Correspondingly, the embodiments of the present invention also provide a control device and an automotive engine.

[0170] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A warm-up control method for an engine, characterized in that, it includes: When the engine enters the cold start mode, obtain the current engine heat generation according to the current engine speed, current engine load, current engine compression ratio, and a preset first correspondence relationship; wherein, the first correspondence relationship is used to indicate the correspondence relationship between the engine speed, engine load, engine compression ratio, and engine heat generation; Calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine; Calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine; Sum up the current engine heat generation, the temperature rise heat, and the heat dissipation change amount to obtain the target total heat generation of the engine; According to the target total heat generation of the engine and a preset second correspondence relationship, obtain the target compression ratio; wherein, the second correspondence relationship is used to indicate the correspondence relationship between the target total heat generation of the engine and the target compression ratio; Determine the warm-up target compression ratio according to the target compression ratio, and control the engine to work at the warm-up target compression ratio.

2. The warm-up control method for an engine according to claim 1, characterized in that, The step of determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to work at the warm-up target compression ratio specifically includes: When the target compression ratio is less than the maximum compression ratio of the engine, use the target compression ratio as the warm-up target compression ratio of the engine, and control the engine to work at the warm-up target compression ratio; When the target compression ratio is greater than the maximum compression ratio of the engine, obtain the optimal compression ratio according to the target total heat generation of the engine and a preset third correspondence relationship; wherein, the third correspondence relationship is used to indicate the correspondence relationship between the target total heat generation of the engine and the optimal compression ratio; Use the optimal compression ratio as the warm-up target compression ratio of the engine, and control the engine to work at the warm-up target compression ratio.

3. The warm-up control method for an engine according to claim 1, characterized in that, After determining the warm-up target compression ratio according to the target compression ratio and controlling the engine to work at the warm-up target compression ratio, it further includes: Obtain the current water temperature of the engine every preset interval period, and calculate the water temperature fluctuation amount of the engine within the preset interval period; When the current water temperature is less than the cold start threshold, return to the step of obtaining the current engine heat generation according to the current engine speed, current engine load, current engine compression ratio, and a preset first correspondence relationship when the engine enters the cold start mode; When the current water temperature is greater than the maximum water temperature threshold, control the engine to alarm and limit the speed and torque, and request the engine to stop; When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is less than the first temperature threshold, control the engine to switch from the cold start mode to the normal mode; When the current water temperature is greater than the cold start threshold and less than the maximum water temperature threshold, and the water temperature fluctuation amount is greater than the first temperature threshold, monitor the water temperature fluctuation amount within the next preset interval period; When the detected water temperature fluctuation amount within the next preset interval period is less than the first temperature threshold, engine distortion recording is performed, and the engine is controlled to switch from the cold start mode to the normal mode; When the detected water temperature fluctuation amount within the next preset interval period is greater than the first temperature threshold, the engine is controlled to give an alarm and limit the speed and torque, and an engine shutdown is requested.

4. The warm-up control method for an engine according to claim 1, characterized in that, the calculation of the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine specifically includes: determining the current coolant flow rate according to the current water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship, wherein the preset fourth corresponding relationship is used to indicate the relationship between the engine water temperature, the engine speed, and the coolant flow rate; determining the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current water temperature and the current coolant flow rate; acquiring the current ambient temperature and the current vehicle speed, and correcting the basic heat dissipation amount of the engine corresponding to the current water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the current water temperature; determining the target coolant flow rate according to the target water temperature of the engine, the current engine speed, and a preset fourth corresponding relationship; determining the basic heat dissipation amount of the engine corresponding to the target water temperature according to the target water temperature and the target coolant flow rate; acquiring the current ambient temperature and the current vehicle speed, and correcting the basic heat dissipation amount of the engine corresponding to the target water temperature according to the current ambient temperature and the current vehicle speed to obtain the heat dissipation amount of the engine corresponding to the target water temperature; taking the difference between the heat dissipation amount of the engine corresponding to the target water temperature and the heat dissipation amount of the engine corresponding to the current water temperature as the engine heat dissipation change amount.

5. The warm-up control method for an engine according to claim 1, characterized in that, before obtaining the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first corresponding relationship when the engine enters the cold start mode, further includes: when it is detected that the vehicle is powered on and a compression ratio sensor fault code is received, controlling the engine to give an alarm and controlling the engine to enter the first fault mode; when the engine enters the first fault mode, acquiring the locking function information of the variable compression ratio mechanism, and when the locking function information is equal to 1, controlling the engine to operate according to the overall engine Map at the locked state compression ratio; when the locking function information is equal to 0, controlling the engine to limit the speed and torque, and requesting the engine to shut down.

6. The warm-up control method for an engine according to claim 1, characterized in that, before obtaining the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio, and a preset first corresponding relationship when the engine enters the cold start mode, further includes: when it is detected that the vehicle is powered on and a compression ratio actuator motor fault code or an oil pump fault code is received, controlling the engine to give an alarm and controlling the engine to enter the second fault mode; When the engine enters the second fault mode, obtain the locking function information of the variable compression ratio mechanism. When the locking function information is equal to 1, control the engine to operate according to the overall engine Map at the locked compression ratio. When the locking function information is equal to 0, control the engine to limit speed and torque, and request the engine to shut down.

7. The engine warm-up control method according to claim 1, characterized in that before obtaining the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio and the preset first corresponding relationship when the engine enters the cold start mode, further includes: When it is detected that the vehicle is powered on and a water temperature sensor fault code is received, control the engine to alarm, limit speed and torque, and request the engine to shut down.

8. The engine warm-up control method according to claim 1, characterized in that before obtaining the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio and the preset first corresponding relationship when the engine enters the cold start mode, further includes: When it is detected that the current water temperature of the engine is lower than the cold start threshold, control the engine to enter the cold start mode; When it is detected that the current water temperature of the engine is higher than the cold start threshold, control the engine to enter the normal working mode.

9. A control device, characterized in that comprises: A heat generation amount acquisition module, configured to obtain the current engine heat generation amount according to the current engine speed, the current engine load, the current engine compression ratio and the preset first corresponding relationship when the engine enters the cold start mode; wherein, the first corresponding relationship is used to indicate the corresponding relationship between the engine speed, the engine load, the engine compression ratio and the engine heat generation amount; A temperature rise heat calculation module, configured to calculate the temperature rise heat required to raise the current water temperature of the engine to the target water temperature of the engine; A heat dissipation change amount calculation module, configured to calculate the heat dissipation change amount from the current water temperature of the engine to the target water temperature of the engine; A target total heat generation amount calculation module, configured to sum the current engine heat generation amount, the temperature rise heat and the heat dissipation change amount to obtain the target total heat generation amount of the engine; A target compression ratio acquisition module, configured to obtain a target compression ratio according to the target total heat generation amount of the engine and the preset second corresponding relationship; wherein, the second corresponding relationship is used to indicate the corresponding relationship between the target total heat generation amount of the engine and the target compression ratio; A warm-up control module, configured to determine a warm-up target compression ratio according to the target compression ratio and control the engine to operate at the warm-up target compression ratio.

10. An automotive engine, characterized in that comprises the control device according to claim 9.

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