A Cold Start Control Method and Related Device for a Hybrid Diesel Engine

Abstract

The present application discloses a cold start control method and related device for a hybrid diesel engine, relating to the field of hybrid diesel engines, including: controlling the motor to reverse-drive the engine at an initial dragging speed, and when the engine speed is greater than the speed threshold, determining the initial fuel injection amount of the engine and performing fuel injection; calculating the combustion coefficient in the engine, where the combustion coefficient is a parameter representing the degree of fuel combustion inside the engine; judging whether the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque; if the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, controlling the motor to disengage from the engine. This method prevents poor fuel combustion through the combustion coefficient, and disengages the motor only when the engine can overcome the idle friction torque and maintain operation. Therefore, the present application can effectively control the cold start of the engine in a hybrid diesel engine.

Description

Technical Field

[0001] The present application relates to the technical field of hybrid diesel engines, and in particular to a hybrid diesel engine cold start control method and related devices. Background Art

[0002] A hybrid diesel engine is a hybrid power system that combines a diesel engine and an electric motor, using both diesel and the electric motor as a power source to drive the vehicle. When the vehicle is cold-started, the engine can be started by the electric motor or by the engine's own starter.

[0003] When the engine is started by dragging the motor backward, the ECU can control the injection during the startup process to increase the air-fuel ratio in the engine and improve the success rate of the engine's cold start. As long as the motor dragging time is not less than the time setting value, the motor will automatically disengage. Therefore, if the engine itself can maintain idling after the motor is disengaged, the engine cold start is successful, otherwise the engine cold start fails. At the same time, in the process of starting the engine by dragging the motor backward, there may be a problem of poor fuel combustion, which will increase the possibility of engine cold start failure. Therefore, the existing method of starting the engine by dragging the motor backward is difficult to accurately control the cold start of the engine.

[0004] Therefore, how to effectively control the cold start of the engine in a hybrid diesel engine is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the present application provides a hybrid diesel engine cold start control method and related devices to achieve the purpose of effectively controlling the cold start of the engine in the hybrid diesel engine. The specific scheme is as follows:

[0006] A first aspect of the present application provides a hybrid diesel engine cold start control method, the hybrid diesel engine cold start control method comprising:

[0007] Controlling the motor to reverse the engine at an initial drag speed, and when the engine speed is greater than a speed threshold, determining an initial fuel injection amount of the engine and performing fuel injection;

[0008] Calculating a combustion coefficient in the engine, the combustion coefficient being a parameter representing the degree of fuel combustion in the engine;

[0009] Determining whether the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque;

[0010] If the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, the motor is controlled to disengage the engine.

[0011] In a possible implementation, it further includes:

[0012] If the combustion coefficient is not greater than a preset threshold, or the torque generated by the engine combustion is less than the absolute value of the idle friction torque, then adjust the initial fuel injection quantity according to the combustion coefficient, and return to execute the step of calculating the combustion coefficient in the engine.

[0013] In a possible implementation, the adjusting the initial fuel injection quantity according to the combustion coefficient includes:

[0014] Query the fuel injection quantity adjustment value corresponding to the combustion coefficient;

[0015] Take the sum of the fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity, and perform fuel injection with the adjusted initial fuel injection quantity.

[0016] In a possible implementation, after querying the fuel injection quantity adjustment value corresponding to the combustion coefficient, the cold start control method further includes:

[0017] If the state of charge (SOC) of the vehicle battery is lower than the power threshold, then correct the fuel injection quantity adjustment value according to the SOC to obtain a corrected fuel injection quantity adjustment value.

[0018] The taking the sum of the fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity includes:

[0019] Take the sum of the corrected fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity.

[0020] In a possible implementation, the correcting the fuel injection quantity adjustment value according to the SOC to obtain a corrected fuel injection quantity adjustment value includes:

[0021] Query the correction coefficient corresponding to the SOC according to the SOC, and take the product of the correction coefficient and the fuel injection quantity adjustment value as the corrected fuel injection quantity adjustment value.

[0022] In a possible implementation, the calculating the combustion coefficient in the engine includes:

[0023] Determine the heat absorbed by the coolant, the exhaust heat of the engine, the output power of the engine, and the fuel heat;

[0024] Calculate the total energy of the heat absorbed by the coolant, the exhaust heat of the engine, and the output power of the engine;

[0025] Take the ratio of the total energy to the fuel heat as the combustion coefficient.

[0026] In a possible implementation, determining that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque includes:

[0027] Calculating the motor torque;

[0028] Determining the corresponding drag speed friction torque according to the current drag speed of the motor, and obtaining the idle friction torque corresponding to the engine idling operation;

[0029] If the motor torque is not less than a preset difference, it is determined that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. The preset difference is: the calculation result of subtracting the absolute value of the drag speed friction torque from the absolute value of the idle friction torque, and the torque generated by the engine combustion is the sum of the motor torque and the absolute value of the drag speed friction torque.

[0030] The second aspect of the present application provides a hybrid diesel engine cold start control system, and the hybrid diesel engine cold start control system includes:

[0031] A reverse drag unit for controlling the motor to reverse drag the engine at an initial drag speed, and when the engine speed is greater than the speed threshold, determining the initial fuel injection amount of the engine and performing fuel injection;

[0032] A calculation unit for calculating the combustion coefficient in the engine, and the combustion coefficient is a parameter representing the degree of fuel combustion inside the engine;

[0033] A judgment unit for judging whether the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. If the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, the control unit is triggered;

[0034] The control unit is used to control the motor to disengage from the engine.

[0035] The third aspect of the present application provides an electronic device, including at least one processor and a memory connected to the processor, wherein:

[0036] The memory is used to store a computer program;

[0037] The processor is used to execute the computer program so that the electronic device can implement the hybrid diesel engine cold start control method of the first aspect or any implementation manner of the first aspect.

[0038] A fourth aspect of the present application provides a computer program product, including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement the hybrid diesel engine cold start control method according to the first aspect or any implementation manner of the first aspect.

[0039] By means of the above technical solution, the present application provides a hybrid diesel engine cold start control method and related devices. The method first reversely drags the engine by controlling the motor at an initial dragging speed. When the engine speed is greater than the speed threshold, the initial fuel injection amount of the engine is determined and fuel is injected. Then, the combustion coefficient inside the engine is calculated, and it is judged whether the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. If both are satisfied, the motor can be disengaged. This method adjusts the initial fuel injection amount according to the calculated combustion coefficient inside the engine, controls the fuel combustion situation inside the engine, effectively prevents poor fuel combustion, and when the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, it means that the torque generated by the engine combustion can already maintain idle operation. Therefore, when the motor is disengaged, the engine can overcome the idle friction torque and maintain operation. Therefore, this method can effectively control the cold start of the engine in a hybrid diesel engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Combined with the drawings and referring to the following specific embodiments, the above and other features, advantages and aspects of the embodiments of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the original parts and elements are not necessarily drawn to scale.

[0041] Figure 1 It is a schematic flowchart of a hybrid diesel engine cold start control method provided by an embodiment of the present application;

[0042] Figure 2 It is a schematic structural diagram of a hybrid diesel engine cold start control method provided by an embodiment of the present application;

[0043] Figure 3 It is a hardware structure block diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The following describes the embodiments of the present application with reference to the drawings in the embodiments of the present application. The terms used in the embodiments of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0045] The following describes the embodiments of the present application with reference to the drawings. Those skilled in the art know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0046] The terms "first", "second" etc. in the specification of the application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable in appropriate circumstances, and this is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0047] A hybrid diesel engine is a hybrid power system that combines a diesel engine and an electric motor. It can be divided into P0, P1, P2, P3 and P4 according to the position of the motor. Among them, the motors of P0, P1 and P2 configurations can be directly connected to the engine, so the engine can be started by reverse dragging the motor.

[0048] When the vehicle is cold started (ambient temperature is generally below -15℃, and can be as low as -40℃), the fuel atomization of the hybrid diesel engine is poor in a low temperature environment, and the compression temperature in the engine cylinder is low, making it difficult for the fuel to burn. Therefore, other methods can be used to assist the engine start. Specifically, the engine can be started by reverse dragging the motor or by the engine's own starter.

[0049] When the engine is started by reverse dragging at a higher drag speed by the motor, the ECU injects fuel according to the engine speed to improve the success rate of the engine's cold start. Since the time setting value is set for the motor to reverse the engine, when the motor's reverse drag time reaches the time setting value, the motor will automatically disengage, and after the motor is disengaged, if the engine can maintain idling by itself, the engine cold start is successful, otherwise the engine cold start fails. The method of reverse dragging the engine for cold start does not interact with the engine, but unilaterally controls the motor with the time setting value. Therefore, the method of reverse dragging the engine for cold start has the possibility of cold start failure, and during the reverse dragging process, there may also be problems with poor fuel combustion, which will increase the possibility of engine cold start failure. Furthermore, when the motor reverses the engine at a higher speed, the engine is prone to mechanical wear.

[0050] When the engine is started by the starter motor at a low speed, a longer start time is required due to the low compression temperature in the engine cylinder. However, due to the excessive current when the engine is started, the starter motor cannot be used for too long. Therefore, the cold start failure rate of the starter motor is high. In order to reduce the cold start failure rate, the fuel injection amount during the start process needs to be increased. However, the increase in fuel injection amount is likely to lead to poor fuel combustion, produce more soot and clog the downstream DPF (Diesel Particulate Filter).

[0051] In summary, both the starting methods of starting the engine by reverse dragging the motor and starting the engine by the starter built into the engine have disadvantages. Therefore, how to effectively control the cold start of the engine in the hybrid diesel engine.

[0052] In order to solve the above problems, an embodiment of the present application provides a hybrid diesel engine cold start control method. In this method, the motor reverses the engine at an initial drag speed, and when the engine speed is greater than the speed threshold, fuel injection is performed to improve the cold start success rate of the engine. After fuel injection, the combustion coefficient in the engine is calculated in real time, and the fuel combustion inside the engine is controlled by the combustion coefficient to effectively prevent poor fuel combustion. The current condition of the engine is determined by judging the combustion coefficient and the torque generated by the engine combustion. After determining that the engine cold start is successful, the motor is controlled to disengage. The hybrid diesel engine cold start control method of the embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0053] Reference Figure 1 , Figure 1 A flow chart of a hybrid diesel engine cold start control method provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, a data processing method provided in an embodiment of the present application may include steps S10 to S13, and these steps are described in detail below.

[0054] S10, controlling the motor to reversely drag the engine at an initial drag speed, and when the engine speed is greater than a speed threshold, determining an initial fuel injection amount of the engine, and performing fuel injection.

[0055] The initial drag speed can be obtained by querying the oil temperature, which is a relatively low speed, and its value can be 100r / min. The speed threshold is the engine injection speed. Only when the engine speed is greater than the speed threshold, the temperature and pressure in the engine combustion chamber are high enough, and the fuel injected into the engine cylinder can be burned. The speed threshold can be between 100r / min and 200r / min.

[0056] In this embodiment, in order to reduce the mechanical wear of the engine caused by the motor during reverse dragging, this embodiment selects to establish oil pressure during the reverse dragging of the motor to reduce mechanical wear. The oil pressure is the driving force for the oil to flow inside the engine, which can ensure that the oil can reach all lubrication points of the engine smoothly and provide necessary lubrication for each component of the engine. When the oil pressure is normal, the oil can form a uniform oil film to protect the parts from direct contact and mechanical wear.

[0057] Specifically, this embodiment controls the motor to first reverse drag the engine at a lower initial dragging speed and gradually increase the dragging speed. Since the oil pressure is positively correlated with the dragging speed, the corresponding relationship can be shown in Table 1. Therefore, when the dragging speed of the motor gradually increases, the oil pressure also gradually increases. Since the oil is viscous and has poor fluidity in a low-temperature environment, the oil pressure has a gradual establishment process of about 3-8 seconds. During the gradual establishment process of the oil pressure, the oil pressure can limit the increasing speed of the motor dragging speed to prevent the dragging speed of the motor from increasing too fast and causing mechanical wear of the engine before the oil pressure is established. When the oil pressure is greater than P0, it can be considered that the oil pressure has been established.

[0058] Table 1

[0059]

[0060] Since the engine speed also gradually increases when the dragging speed of the motor gradually increases, when the engine speed is greater than the speed threshold, the initial fuel injection volume can be determined according to the coolant temperature of the engine and the exhaust temperature of the engine. The corresponding relationship between the coolant temperature, the exhaust temperature and the initial fuel injection volume can be shown in Table 2:

[0061] Table 2

[0062]

[0063] Among them, the coolant temperature can be measured by a temperature sensor, and the exhaust temperature can be measured by an exhaust temperature sensor or a temperature sensor before the DOC (Diesel Oxidation Catalyst). After determining the initial fuel injection volume, control the engine to inject fuel at this initial fuel injection volume per second.

[0064] S11. Calculate the combustion coefficient in the engine. The combustion coefficient is a parameter indicating the degree of fuel combustion inside the engine.

[0065] Among them, the energy generated by the combustion of fuel injected into the engine is mainly consumed as follows: the heat absorbed by the coolant, the exhaust heat, the output power of the engine (the work done to overcome the frictional torque), and other losses (which account for a relatively small proportion and can be ignored). Therefore, the greater the total energy of the heat absorbed by the coolant, the exhaust heat, and the output power of the engine, the more fully the fuel burns inside the engine; otherwise, the combustion is worse. Therefore, in this embodiment, the ratio of the total energy of the heat absorbed by the coolant, the exhaust heat, and the output power of the engine to the fuel heat is defined as the combustion coefficient.

[0066] Specifically, the specific process of calculating the combustion coefficient in this embodiment can be as shown in Steps 1 to 3:

[0067] Step 1: Determine the heat absorbed by the coolant, the exhaust heat of the engine, the output power of the engine, and the fuel heat.

[0068] Step 2: Calculate the total energy of the heat absorbed by the coolant, the exhaust heat of the engine, and the output power of the engine.

[0069] Step 3: Take the ratio of the total energy to the fuel heat as the combustion coefficient.

[0070] Among them, the heat absorbed by the coolant can be determined by calculating based on the temperature change of the coolant and the specific heat capacity of the coolant. The exhaust heat of the engine can be determined by calculating based on the temperature change of the exhaust and the specific heat capacity of the coolant. The power of the engine can be obtained by calculating in real time according to the frictional torque of the engine and the motor torque, and the output power of the engine is the cumulative value of the power of the engine during the fuel combustion process. The fuel heat can be obtained by calculating based on the fuel calorific value and the fuel injection volume. The fuel calorific value is the heat generated by the complete combustion of unit weight of fuel, and the fuel injection volume is the current fuel injection volume of the engine. In this embodiment, the fuel type is diesel.

[0071] Taking the diesel combustion process from time t0 to time t1 as an example, the calculation formulas for the heat absorbed by the coolant, the exhaust heat of the engine, the power of the engine, and the fuel heat in this embodiment can be as follows:

[0072] Heat absorbed by the coolant = (coolant temperature at time t1 - coolant temperature at time t0) × specific heat capacity of the coolant;

[0073] Exhaust heat of the engine = (exhaust temperature at time t1 - exhaust temperature at time t0) × specific heat capacity of the coolant;

[0074] Power of the engine = [(|frictional torque of the diesel engine| + motor torque) × rotational speed] / 9550;

[0075] Fuel heat = diesel calorific value × fuel injection volume;

[0076] Among them, the temperatures of the coolant at the front and rear times and the temperatures of the exhaust gas at the front and rear times can both be obtained by temperature sensors. The specific heat capacity of the coolant can be directly obtained by looking up a table. The fuel injection amount is the total fuel injection amount from time t0 to time t1, which can be obtained by measuring the engine.

[0077] In this embodiment, the ratio of the total energy to the fuel heat is used as the combustion coefficient. Specifically, in this embodiment, the total energy can be used as the numerator and the fuel heat as the denominator. Then, the larger the combustion coefficient, the greater the proportion of the total heat absorbed by the coolant, the exhaust heat, and the output power energy of the engine in the total heat generated by fuel combustion, and the more complete the combustion of the fuel inside the engine; the smaller the combustion coefficient, the worse the combustion of the fuel inside the engine.

[0078] Of course, in this embodiment, the total energy can also be used as the denominator and the fuel heat as the numerator. Then, the smaller the combustion coefficient, the greater the proportion of the total heat absorbed by the coolant, the exhaust heat, and the output power energy of the engine in the total heat generated by fuel combustion, and the more complete the combustion of the fuel inside the engine; the larger the combustion coefficient, the worse the combustion of the fuel inside the engine.

[0079] S12. Determine whether the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque;

[0080] S13. If the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, then control the motor to disengage from the engine.

[0081] Among them, the preset threshold is the limit value of the combustion coefficient. In this embodiment, the value of the preset threshold can be 0.7. The idle friction torque refers to the torque generated due to the friction between the internal parts of the engine when the engine is in the idle condition (the engine runs without load). The idle friction torque can consume a part of the output power of the engine.

[0082] Specifically, in this embodiment, it mainly judges whether the torque generated by the engine combustion is not less than the absolute value of the idle friction torque by the magnitude of the motor torque. The specific process can be as shown in steps four to six:

[0083] Step four: Calculate the motor torque;

[0084] Step five: Determine the corresponding drag speed friction torque according to the current drag speed of the motor, and obtain the idle friction torque corresponding to the engine idling operation;

[0085] Step six: If the motor torque is not less than the preset difference, then determine that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque.

[0086] Among them, the motor torque can be obtained by calculating the rotational speed of the motor and the output power of the motor. The preset difference is the calculation result of the absolute value of the idle friction torque minus the absolute value of the friction torque at the dragging rotational speed. The friction torque at the dragging rotational speed is the friction torque between transmission components when the motor drags the engine in reverse. Both the idle friction torque and the friction torque at the dragging rotational speed can be determined by the rotational speed. The rotational speed under the idle condition is generally a fixed value, and the friction torque at the dragging rotational speed can be determined by the rotational speed at which the motor drags the engine in reverse. The corresponding relationship between the rotational speed and the friction torque can be as shown in Table 3:

[0087] Table 3

[0088]

[0089] The torque generated by engine combustion is the sum of the motor torque and the absolute value of the friction torque at the dragging rotational speed. And when the engine can maintain idle operation by itself, at this time, when the torque generated by engine combustion is greater than the idle friction torque. Therefore, when the motor torque is not less than the calculation result of the absolute value of the idle friction torque minus the absolute value of the friction torque at the dragging rotational speed, it can indicate that the engine can maintain idle operation by itself. Specifically, it can be expressed in the form of a formula as follows:

[0090] The torque generated by engine combustion - |idle friction torque| ≥ 0, indicating that the engine can maintain idle operation by itself;

[0091] Since the torque generated by engine combustion = |friction torque at the dragging rotational speed| + motor torque;

[0092] Then |friction torque at the dragging rotational speed| + motor torque - |idle friction torque| ≥ 0;

[0093] Therefore, when the motor torque ≥ |idle friction torque| - |friction torque at the dragging rotational speed|, it indicates that the engine can maintain idle operation by itself.

[0094] For example, when the idle speed is 600 r / min, the rotational speed at which the motor drags the engine to start in reverse is 800 r / min, and the motor torque is 6 Nm. According to Table 4, the idle friction torque is -48 and the friction torque at the dragging rotational speed is -42. Since the motor torque is not less than the calculation result of the absolute value of the idle friction torque minus the absolute value of the friction torque at the dragging rotational speed (6 ≥ |-48| - |-42|), it is determined that the torque generated by engine combustion is not less than the absolute value of the idle friction torque, indicating that the engine can maintain idle operation by itself at this time.

[0095] Further, if fuel injection is performed at the initial fuel injection amount at the current moment, and the combustion coefficient calculated at the current moment is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, then at this time, the motor can be controlled to disengage from the engine, and the ECU controls the engine. If fuel injection is performed at the initial fuel injection amount at the current moment, the combustion coefficient is not greater than the preset threshold, or the torque generated by the engine combustion is less than the absolute value of the idle friction torque, then the initial fuel injection amount needs to be adjusted according to the combustion coefficient, fuel injection is performed at the adjusted initial fuel injection amount at the next moment, and it is determined again whether the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque.

[0096] Further, the initial fuel injection amount adjusted according to the combustion coefficient should not exceed the maximum fuel injection amount (full-load fuel injection amount) at the current engine speed. The maximum fuel injection amount has been preset in the ECU in advance, and the maximum fuel injection amounts of different engines at the same speed are different. Specifically, when the adjusted initial fuel injection amount is less than the maximum fuel injection amount at the current engine speed, fuel injection is performed according to the adjusted initial fuel injection amount; when the adjusted initial fuel injection amount is equal to the maximum fuel injection amount at the current engine speed, fuel injection is performed according to one of them; when the adjusted initial fuel injection amount is greater than the maximum fuel injection amount at the current engine speed, fuel injection is performed according to the maximum fuel injection amount at the current engine speed.

[0097] Specifically, the specific process of adjusting the initial fuel injection amount according to the combustion coefficient in this embodiment can be as shown in Step Seven and Step Eight:

[0098] Step Seven: Query the fuel injection amount adjustment value corresponding to the combustion coefficient;

[0099] Step Eight: Take the sum of the fuel injection amount adjustment value and the initial fuel injection amount as the adjusted initial fuel injection amount, and perform fuel injection with the adjusted initial fuel injection amount.

[0100] Among them, the corresponding relationship between the combustion coefficient and the fuel injection amount adjustment value can be as shown in Table 4:

[0101] Table 4

[0102]

[0103] When the combustion coefficient is large, it indicates that the combustion condition in the engine is good, and the fuel injection amount adjustment value can be increased on the basis of the initial fuel injection amount; when the combustion coefficient is small, it indicates that the combustion condition in the engine is poor, and the fuel injection amount adjustment value can be subtracted on the basis of the initial fuel injection amount to prevent carbon soot generated by poor fuel combustion from clogging the DPF.

[0104] Since the engine automatically charges the battery while providing power when the vehicle's battery level is low. Therefore, in this embodiment, to ensure that the engine can still start successfully in cold condition under low battery level, after querying and determining the fuel injection quantity adjustment value according to the combustion coefficient, if the vehicle is in a low battery level state, the fuel injection quantity adjustment value needs to be corrected according to the vehicle's SOC (State of Charge, battery level). Specifically, if the vehicle's battery level SOC is not lower than the battery level threshold, the fuel injection quantity adjustment value is not corrected; if the vehicle's battery level SOC is lower than the battery level threshold, the fuel injection quantity adjustment value is corrected according to the SOC, and the sum of the corrected fuel injection quantity adjustment value and the initial fuel injection quantity is used as the adjusted initial fuel injection quantity. In this embodiment, the battery level threshold is 10%.

[0105] Among them, in this embodiment, the correction coefficient corresponding to the SOC can be queried according to the SOC, and the product of the correction coefficient and the fuel injection quantity adjustment value is used as the corrected fuel injection quantity adjustment value. Of course, in this embodiment, a corresponding relationship table between the SOC and the fuel injection quantity adjustment value can also be directly constructed to facilitate directly querying and obtaining the fuel injection quantity adjustment value corresponding to the SOC. The corresponding relationship table between the SOC and the correction coefficient can be shown in Table 5 as follows:

[0106] Table 5

[0107]

[0108] Of course, after the fuel injection quantity adjustment value is corrected by the SOC, the adjusted initial fuel injection quantity should also not exceed the maximum fuel injection quantity at the current engine speed. The smaller fuel injection quantity between the adjusted initial fuel injection quantity and the maximum fuel injection quantity at the current engine speed is selected as the fuel injection quantity at the current moment and fuel injection is performed; when the adjusted initial fuel injection quantity is equal to the maximum fuel injection quantity at the current engine speed, fuel injection is performed according to one of the fuel injection quantities.

[0109] As the fuel injection quantity increases, the torque output by the engine combustion increases synchronously, while the driving torque of the motor gradually decreases.

[0110] A cold start control method provided by an embodiment of the present application. First, the motor is controlled to reverse-drive the engine at an initial driving speed. When the engine speed is greater than the speed threshold, the initial fuel injection amount of the engine is determined, and then the combustion coefficient inside the engine is calculated and fuel is injected. It is judged whether the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. If both are satisfied, the motor can be disengaged. This method adjusts the initial fuel injection amount according to the calculated combustion coefficient inside the engine, controls the fuel combustion situation inside the engine, effectively prevents poor fuel combustion and excessive smoke, and when the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, it means that the torque generated by the engine combustion can already maintain idle operation. Therefore, when the motor is disengaged, the engine can overcome the idle friction torque and maintain operation. Therefore, this method can effectively control the cold start of the engine in a hybrid diesel engine.

[0111] The above introduces a cold start control method for a hybrid diesel engine provided by an embodiment of the present application. The following will introduce a system applying the above cold start control method for a hybrid diesel engine.

[0112] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of a cold start control system for a hybrid diesel engine provided by an embodiment of the present application. As Figure 2 shown, the cold start control system for a hybrid diesel engine includes:

[0113] A reverse-driving unit 100, configured to control the motor to reverse-drive the engine at an initial driving speed, determine the initial fuel injection amount of the engine when the engine speed is greater than the speed threshold, and perform fuel injection;

[0114] A calculation unit 110, configured to calculate the combustion coefficient inside the engine, and the combustion coefficient is a parameter representing the degree of fuel combustion inside the engine;

[0115] A judgment unit 120, configured to judge whether the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. If the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, the control unit 130 is triggered;

[0116] A control unit 130, configured to control the motor to disengage from the engine.

[0117] In a possible implementation, the cold start control system for a hybrid diesel engine may further include an adjustment unit:

[0118] The adjustment unit is configured to, when the combustion coefficient is not greater than the preset threshold, or the torque generated by the engine combustion is less than the absolute value of the idle friction torque, adjust the initial fuel injection amount according to the combustion coefficient, and return to trigger the calculation unit 110.

[0119] In a possible implementation, the adjustment unit adjusts the initial fuel injection quantity according to the combustion coefficient, which may specifically include:

[0120] A query subunit, configured to query the fuel injection quantity adjustment value corresponding to the combustion coefficient;

[0121] A fuel quantity subunit, configured to use the sum of the fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity, and perform fuel injection with the adjusted initial fuel injection quantity.

[0122] In a possible implementation, after executing the above query subunit, the hybrid diesel engine cold start control system may further include:

[0123] A correction unit, configured to correct the fuel injection quantity adjustment value according to the SOC when the state of charge (SOC) of the vehicle battery is lower than the power threshold, to obtain the corrected fuel injection quantity adjustment value.

[0124] The above fuel quantity subunit may specifically be configured as:

[0125] Use the sum of the corrected fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity.

[0126] In a possible implementation, the correction unit may specifically be configured as:

[0127] Query the correction coefficient corresponding to the SOC according to the SOC, and use the product of the correction coefficient and the fuel injection quantity adjustment value as the corrected fuel injection quantity adjustment value.

[0128] In a possible implementation, the calculation unit 110 may specifically be configured as:

[0129] Determine the heat absorbed by the coolant, the exhaust heat of the engine, the output power of the engine, and the fuel heat, calculate the total energy of the heat absorbed by the coolant, the exhaust heat of the engine, and the output power of the engine, and use the ratio of the total energy to the fuel heat as the combustion coefficient.

[0130] In a possible implementation, in the judgment unit 120, judging that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque may specifically be configured as:

[0131] Calculate the motor torque, determine the corresponding drag speed friction torque according to the current drag speed of the motor, and obtain the idle friction torque corresponding to the engine idling operation. If the motor torque is not less than the preset difference, it is determined that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. The preset difference is the calculation result of subtracting the absolute value of the drag speed friction torque from the absolute value of the idle friction torque. The torque generated by the engine combustion is the sum of the motor torque and the absolute value of the drag speed friction torque.

[0132] An embodiment of the present application also provides an electronic device. Refer to Figure 3 As shown, it shows a schematic structural diagram of an electronic device suitable for implementing the electronic device in the embodiments of the present application. The electronic device in the embodiments of the present application may include, but is not limited to, fixed terminals such as mobile phones, laptop computers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), desktop computers, and the like. Figure 3 The electronic device shown is merely an example and should not impose any limitation on the functions and usage scope of the embodiments of the present application.

[0133] As Figure 3 shown, the electronic device may include a processing device (such as a central processing unit, a graphics processing unit, etc.) 301, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 302 or the program loaded from the storage device 308 into the random access memory (RAM) 303. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 303. The processing device 301, the ROM 302, and the RAM 303 are connected to each other through a bus 304. The input / output (I / O) interface 305 is also connected to the bus 304.

[0134] Generally, the following devices may be connected to the I / O interface 305: an input device 306 including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 307 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 308 including, for example, a memory card, a hard disk, etc.; and a communication device 309. The communication device 309 may allow the electronic device to communicate with other devices wirelessly or wiredly to exchange data. Although Figure 3 the electronic device with various devices is shown, it should be understood that it is not required to implement or have all the shown devices. Instead, more or fewer devices may be implemented or had.

[0135] An embodiment of the present application also provides a computer program product, including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement any one of the hybrid diesel engine cold start control methods provided by the embodiments of the present application.

[0136] An embodiment of the present application also provides a computer-readable storage medium, which carries one or more computer programs, and when the one or more computer programs are executed by an electronic device, can enable the electronic device to implement any one of the hybrid diesel engine cold start control methods provided by the embodiments of the present application.

[0137] It should be further noted that the system 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 system embodiments provided in this application, the connection relationships between the modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines.

[0138] Through the description of the above embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general hardware. Of course, it can also be implemented by dedicated hardware including application-specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components, etc. Generally, functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structures used to implement the same function can also be various, such as analog circuits, digital circuits or dedicated circuits. However, for this application, software program implementation is a better implementation method in more cases. Based on such an understanding, the technical solution of this application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk or optical disc of a computer, and includes several instructions to enable a computer device (which can be a personal computer, training device, or network device, etc.) to execute the methods described in various embodiments of this application.

[0139] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product.

[0140] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are all or partially generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or a data center that includes one or more integrated available media. The available medium may be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0141] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the related parts, reference can be made to the description of the method embodiments.

[0142] It can be understood that before using the technical solutions disclosed in the embodiments of the present disclosure, the types, usage scopes, usage scenarios, etc. of the personal information involved in the present disclosure should be informed to the user and the user's authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations.

[0143] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cold start control method for a hybrid diesel engine, characterized in that, The cold start control method for the hybrid diesel engine includes: Controlling the motor to reverse-drive the engine at the initial dragging speed. When the engine speed is greater than the speed threshold, determining the initial fuel injection quantity of the engine and performing fuel injection; Calculating the combustion coefficient in the engine, where the combustion coefficient is a parameter representing the degree of fuel combustion inside the engine; Judging whether the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque; If the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, controlling the motor to disengage from the engine; The calculating the combustion coefficient in the engine includes: Determining the heat absorbed by the coolant, the exhaust heat of the engine, the output power of the engine, and the fuel heat; Calculating the total energy of the heat absorbed by the coolant, the exhaust heat of the engine, and the output power of the engine; Taking the ratio of the total energy to the fuel heat as the combustion coefficient, where the total energy is the numerator and the fuel heat is the denominator.

2. The cold start control method of the hybrid diesel engine according to claim 1, characterized in that, It also includes: If the combustion coefficient is not greater than the preset threshold, or the torque generated by the engine combustion is less than the absolute value of the idle friction torque, adjusting the initial fuel injection quantity according to the combustion coefficient, and returning to execute the step of calculating the combustion coefficient in the engine.

3. The cold start control method for a hybrid diesel engine according to claim 2, characterized in that, The adjusting the initial fuel injection quantity according to the combustion coefficient includes: Querying the fuel injection quantity adjustment value corresponding to the combustion coefficient; Taking the sum of the fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity, and performing fuel injection with the adjusted initial fuel injection quantity.

4. The cold start control method for a hybrid diesel engine according to claim 3, characterized in that, After querying the fuel injection quantity adjustment value corresponding to the combustion coefficient, the cold start control method further includes: If the state of charge (SOC) of the vehicle battery is lower than the power threshold, correcting the fuel injection quantity adjustment value according to the SOC to obtain a corrected fuel injection quantity adjustment value. The taking the sum of the fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity includes: Taking the sum of the corrected fuel injection quantity adjustment value and the initial fuel injection quantity as the adjusted initial fuel injection quantity.

5. The cold start control method of the hybrid diesel engine according to claim 4, characterized in that, The correcting the fuel injection quantity adjustment value according to the SOC to obtain a corrected fuel injection quantity adjustment value includes: Querying the correction coefficient corresponding to the SOC according to the SOC, and taking the product of the correction coefficient and the fuel injection quantity adjustment value as the corrected fuel injection quantity adjustment value.

6. The cold start control method of the hybrid diesel engine according to claim 1, characterized in that, Judging whether the torque generated by the engine combustion is not less than the absolute value of the idle friction torque includes: Calculating the motor torque; Determining the corresponding dragging speed friction torque according to the current dragging speed of the motor, and obtaining the idle friction torque corresponding to the engine idling operation; If the motor torque is not less than a preset difference value, determining that the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, where the preset difference value is the calculation result of subtracting the absolute value of the dragging speed friction torque from the absolute value of the idle friction torque, and the torque generated by the engine combustion is the sum of the motor torque and the absolute value of the dragging speed friction torque.

7. A cold start control system for a hybrid diesel engine, characterized in that, The hybrid diesel engine cold start control system includes: A reverse dragging unit, configured to control the motor to reverse drag the engine at an initial dragging speed. When the engine speed is greater than a speed threshold, determine the initial fuel injection quantity of the engine and perform fuel injection; A calculation unit, configured to calculate a combustion coefficient in the engine, where the combustion coefficient is a parameter representing the degree of fuel combustion inside the engine; A judgment unit, configured to judge whether the combustion coefficient is greater than a preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque. If the combustion coefficient is greater than the preset threshold and the torque generated by the engine combustion is not less than the absolute value of the idle friction torque, trigger the control unit; The control unit, configured to control the motor to disengage from the engine; The calculation unit is specifically configured as: Determine the heat absorbed by the coolant, the exhaust heat of the engine, the output power of the engine, and the fuel heat; calculate the total energy of the heat absorbed by the coolant, the exhaust heat of the engine, and the output power of the engine; use the ratio of the total energy to the fuel heat as the combustion coefficient, where the total energy is used as the numerator and the fuel heat is used as the denominator.

8. An electronic device, characterized in that, Comprising at least one processor and a memory connected to the processor, wherein: The memory is used to store a computer program; The processor is used to execute the computer program so that the electronic device can implement the hybrid diesel engine cold start control method as described in any one of claims 1 to 6.

9. A computer program product, characterized in that, Comprising computer-readable instructions, when the computer-readable instructions run on an electronic device, enabling the electronic device to implement the hybrid diesel engine cold start control method as described in any one of claims 1 to 6.

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