Engine low-temperature starting protection method and device, engine controller and vehicle
By obtaining engine coolant temperature and oil pressure at extremely low temperatures, and using a low-speed dragging and speed limiting method, the problem of inaccurate friction torque prediction during engine start-up in range-extended hybrid vehicles is solved, achieving rapid engine start-up and life protection.
Patent Information
- Application Number
- CN202511772216.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-01-20
AI Technical Summary
Under extremely low temperature conditions, when the engine of a range-extended hybrid vehicle starts, the existing control strategy leads to inaccurate estimation of friction torque, which may cause engine wear due to high-speed starting, affecting its reliability and lifespan.
By obtaining the engine's initial start-up coolant temperature, if it is below the threshold, low-speed operation is used to control fuel injection and ignition. Start-up is initiated after the oil pressure reaches the threshold. The engine speed is limited by the maximum speed limit table to ensure that the lubrication system is established before starting.
At extremely low temperatures, a balance is achieved between rapid engine start-up and lifespan protection, avoiding engine damage caused by inaccurate friction torque and ensuring normal engine lubrication and service life.
Smart Images
Figure CN121363501A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The embodiments of the present specification relate to the technical field of vehicles, in particular to an engine low-temperature starting protection method and device, an engine controller and a vehicle. BACKGROUND
[0002] In a fuel vehicle, engine starting is usually dragged by a starter at a low speed, and after a long process of establishing oil pressure and lubrication, oil injection and ignition are started. However, in a range-extending hybrid vehicle, the engine is directly dragged by a high-power motor, which has the characteristics of large drag torque and fast speed increase. Under low-temperature conditions, the internal friction resistance of the engine increases sharply, and the friction torque changes with temperature and speed in a complex and nonlinear manner. If the existing control strategy directly uses the empirical model or simple estimated value at normal temperature, the estimation of low-temperature friction torque will be seriously inaccurate.
[0003] Based on the inaccurate torque estimation, the motor often uses a high drag speed to start in order to start quickly. This high-speed direct starting mode is prone to cause abnormal wear and seriously affect the reliability and service life of the engine under extremely low-temperature conditions, because the high-speed operation will cause the key friction pairs (such as the crankshaft and bearing shell, and the piston and cylinder sleeve) in the engine to be in a semi-dry friction or boundary lubrication state when the oil pressure in the lubrication system has not been established.
[0004] Therefore, there is an urgent need to provide an engine low-temperature starting protection method to effectively balance the accurate real-time control of the rapid starting demand and the engine life protection under extremely low-temperature conditions. SUMMARY
[0005] Therefore, there is an urgent need to provide an engine low-temperature starting protection method to effectively balance the accurate real-time control of the rapid starting demand and the engine life protection under extremely low-temperature conditions.
[0006] The engine low-temperature starting protection method provided by the embodiments of the present specification is applied to an engine controller of an engine in a vehicle, the engine being tightly coupled with an electric machine; the method comprises: acquiring a current first starting water temperature of the engine; if the first starting water temperature is lower than a preset water temperature threshold, sending a low-speed dragging request flag and a target torque value corresponding to the first starting water temperature and a preset low-speed to a vehicle controller, so that the vehicle controller sends a dragging instruction to the electric machine in response to the low-speed dragging request flag, to instruct the electric machine to drag the engine to operate at a low speed according to the target torque value; in the process that the electric machine drags the engine and drives an oil pump to work, the engine is controlled to be prohibited from fuel injection and ignition, and in the case that the oil pressure of the engine is detected to rise to be higher than a preset oil pressure threshold, the engine is started; according to the oil temperature of the engine when the engine is started, a target limit speed is acquired by querying a preset engine maximum speed limit table; the engine maximum speed limit table describes the maximum speed of the engine at different oil temperatures; the running speed of the engine is limited to be below the target limit speed.
[0007] In some embodiments, the target torque value is determined based on a pre-established engine low-temperature torque model, the engine low-temperature torque model describing the torque values corresponding to different water temperatures and different engine speeds; the engine low-temperature torque model is established by: on a low-temperature powertrain test bench, for a plurality of engine samples, scanning and measuring the torque of the engine samples at different water temperatures and different engine speeds; taking the average of the torques measured multiple times, and constructing a two-dimensional data model comprising the correspondence between water temperature, speed and torque by using the average value; the torque is a friction torque.
[0008] In some embodiments, in the engine low-temperature torque model, any of the water temperatures is greater than or equal to -40℃ and less than or equal to 0℃; or, any of the engine speeds is greater than or equal to 700 r / min.
[0009] In some embodiments, in the engine low-temperature torque model, the difference between adjacent water temperatures is less than 5℃, or the difference between adjacent engine speeds is less than 500 r / min.
[0010] In some embodiments, the preset low speed is a speed lower than a normal idle speed of the engine.
[0011] In some embodiments, in the engine maximum speed limit table, any of the oil temperatures is greater than or equal to -40℃ and less than or equal to 0℃, and the maximum speed of the engine corresponding to different oil temperatures is obtained through real vehicle test calibration.
[0012] In some embodiments, the method further comprises: if the first starting water temperature is higher than or equal to the preset water temperature threshold, starting the engine, and according to the engine oil temperature at the time of starting the engine, querying a preset engine maximum speed limit table to obtain a target limit speed; wherein the engine maximum speed limit table describes the engine maximum speed at different engine oil temperatures; and limiting the running speed of the engine to be below the target limit speed.
[0013] The embodiment of the present specification provides an engine low-temperature starting protection device applied to an engine controller of an engine in a vehicle, the engine being tightly coupled with an electric machine; the device comprises: a water temperature acquisition module configured to acquire a current first starting water temperature of the engine; a low-speed running control module configured to, if the first starting water temperature is lower than a preset water temperature threshold, send a low-speed dragging request flag and a target torque value corresponding to the first starting water temperature and a preset low speed to a vehicle controller, so that the vehicle controller sends a dragging instruction to the electric machine in response to the low-speed dragging request flag, to instruct the electric machine to drag the engine to run at a low speed according to the target torque value; an engine oil pressure monitoring module configured to, during the process that the electric machine drags the engine and drives an engine oil pump to work, control the engine to be prohibited from fuel injection and ignition, and start the engine if it is detected that the engine oil pressure of the engine rises to be higher than a preset engine oil pressure threshold; a speed limit module configured to, according to the engine oil temperature at the time of starting the engine, query a preset engine maximum speed limit table to obtain a target limit speed; wherein the engine maximum speed limit table describes the engine maximum speed at different engine oil temperatures; and limit the running speed of the engine to be below the target limit speed.
[0014] The embodiment of the present specification provides an engine controller comprising a memory and a processor, the memory storing a computer program, and the processor implementing the engine low-temperature starting protection method of any of the above embodiments when executing the computer program.
[0015] The embodiment of the present specification provides a vehicle, which is a range-extending hybrid vehicle, and the engine controller of any of the above embodiments.
[0016] In the multiple embodiments provided in the specification, the engine is tightly coupled with the motor. First, the current first-start water temperature of the engine is acquired. If the first-start water temperature is lower than a preset water temperature threshold, a low-speed dragging request flag and a target torque value corresponding to the first-start water temperature and the preset low-speed are sent to the vehicle controller, so that the vehicle controller sends a dragging instruction to the motor in response to the low-speed dragging request flag, to instruct the motor to drag the engine to run at a low speed according to the target torque value. Then, during the process of dragging the engine by the motor and driving the oil pump to work, the engine is controlled to prohibit fuel injection and ignition, and the engine is started when the oil pressure of the engine is detected to rise to be higher than a preset oil pressure threshold. Then, according to the oil temperature of the engine when the engine is started, a target limit speed is acquired by querying a preset engine maximum speed limit table. The engine maximum speed limit table describes the maximum speed of the engine under different oil temperatures. The running speed of the engine is limited to be lower than the target limit speed. In this way, the accurate real-time control of balancing the demand for rapid starting and the protection of engine life can be effectively achieved in an extremely low temperature environment. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 FIG. 1 is a flow diagram of an engine low-temperature starting protection method provided by an embodiment of the specification; Figure 2 FIG. 2 is a schematic diagram of an engine low-temperature starting protection device provided by an embodiment of the specification; Figure 3 FIG. 3 is a schematic diagram of an engine controller provided by an embodiment of the specification. DETAILED DESCRIPTION
[0018] In order to enable those skilled in the art to better understand the schemes of the specification, the technical schemes in the embodiments of the specification will be described clearly and completely in combination with the drawings in the embodiments of the specification. Obviously, the described embodiments are only part of the embodiments of the specification, rather than all the embodiments of the specification. Based on the embodiments in the specification, all other embodiments obtained by those skilled in the art without making creative efforts fall within the protection scope of the specification.
[0019] The embodiment of the specification provides an application scenario example of an engine low-temperature starting protection method. The application scenario is a range-extender hybrid vehicle, which includes an engine and a motor in a tightly coupled type.
[0020] The embodiment of the specification provides an engine low-temperature starting protection method. Please refer to Figure 1 , Figure 1is a flowchart of an engine low temperature start protection method provided by the embodiments of the present disclosure. The embodiments provide method operation steps as shown in the flowchart, but more or less operation steps can be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is only one of the many execution orders of the steps, and does not represent the only execution order. In actual system or server product execution, the method order shown in the embodiments can be executed in sequence or in parallel (for example, in a parallel processor or multi-thread processing environment). The engine low temperature start protection method can be applied to a motor control unit (MCU), specifically as shown in Figure 1 The engine low temperature start protection method can include the following steps.
[0021] Step S110: Obtain the current first start water temperature of the engine.
[0022] The first start of the engine can refer to the first start of the engine from a cooling state after the engine in the vehicle has been stationary for a long time, especially in a low temperature environment.
[0023] Step S120: If the first start water temperature is lower than the preset water temperature threshold, send a low speed drag request flag and a target torque value corresponding to the first start water temperature and the set low speed to the vehicle control unit (VCU) to make the vehicle control unit send a drag instruction to the motor in response to the low speed drag request flag to instruct the motor to drag the engine to run at a low speed according to the target torque value.
[0024] Step S130: During the process of the motor dragging the engine and driving the oil pump to work, control the engine to prohibit fuel injection and ignition, and start the engine when the engine oil pressure is detected to rise to exceed the preset oil pressure threshold.
[0025] For example, while the engine rotates under the low speed drag of the motor, the oil pump works, and the oil pressure is established. When the oil pressure is greater than the oil pressure threshold, the engine lubrication system is normal, and the engine is started.
[0026] Step S140: According to the oil temperature when the engine is started, query the preset engine maximum speed limit table to obtain a target limit speed; wherein the engine maximum speed limit table describes the engine maximum speed under different oil temperatures.
[0027] Step S150: Limit the running speed of the engine to be below the target limit speed.
[0028] In the above embodiments, at an extremely low temperature, the engine is driven at a low speed by the motor, and when the oil pressure is greater than the oil pressure threshold, the motor is started normally, so that the engine can be lubricated during the starting process at an extremely low temperature, and then started normally, so as to avoid damage to the engine and affect the service life of the engine due to high speed driving of the engine by the motor at an extremely low temperature.
[0029] In some embodiments, the target torque value is determined based on a pre-established engine low-temperature torque model, which describes the corresponding torque values at different water temperatures and different engine speeds.
[0030] In the present embodiment, the engine low-temperature torque model can be established by the following method: on a low-temperature powertrain test bench, for a plurality of engine samples, scanning and measuring the torque of the engine samples at different water temperatures and different engine speeds; and averaging the torques measured multiple times to construct a two-dimensional data model containing the corresponding relationship between water temperature, speed and torque.
[0031] In some embodiments, the torque is a friction torque. That is, the torque in the engine low-temperature torque model is a friction torque, and the target torque value determined based on the engine low-temperature torque model is a target friction torque value.
[0032] In some embodiments, in the engine low-temperature torque model, any water temperature is greater than or equal to -40°C and less than or equal to 0°C; or, any engine speed is greater than or equal to 700 r / min.
[0033] For example, in the engine low-temperature torque model, different water temperatures can include at least -40°C, -35°C, -30°C, -20°C, -10°C and 0°C. For example, different engine speeds can include at least 700 r / min, 1000 r / min, 1500 r / min, 2000 r / min and 2500 r / min.
[0034] In some embodiments, in the engine low-temperature torque model, the difference between adjacent water temperatures is less than 5°C, or the difference between adjacent engine speeds is less than 500 r / min. It can be understood that the difference between adjacent water temperatures can be determined according to actual conditions, for example, it can be less than 10°C, 15°C or other values.
[0035] In some embodiments, the set low speed can be a speed set lower than the normal idle speed of the engine.
[0036] In some embodiments, in the engine maximum speed limit table, for any engine oil temperature greater than or equal to -40℃ and less than or equal to 0℃, the engine maximum speed corresponding to different engine oil temperatures is obtained through real vehicle test calibration.
[0037] Exemplarily, in the engine maximum speed limit table, the engine oil temperature can at least include -40℃, -35℃, -30℃, -25℃, -20℃, -10℃ and 0℃.
[0038] In some embodiments, the engine low-temperature starting protection method can further include: if the first starting water temperature is higher than or equal to the preset water temperature threshold, starting the engine, and according to the engine oil temperature at the time of starting the engine, querying a preset engine maximum speed limit table to obtain a target limit speed; wherein the engine maximum speed limit table describes the engine maximum speed under different engine oil temperatures; and limiting the running speed of the engine below the target limit speed.
[0039] The embodiments of the present specification provide an engine low-temperature starting protection device applied to an engine controller of an engine in a vehicle, please refer to Figure 2 The engine low-temperature starting protection device can include a water temperature acquisition module 210, a low-speed running control module 220, an oil pressure monitoring module 230 and a speed limiting module 240.
[0040] The water temperature acquisition module 210 is configured to acquire the current first starting water temperature of the engine. The low-speed running control module 220 is configured to, if the first starting water temperature is lower than the preset water temperature threshold, send a low-speed dragging request flag and a target torque value corresponding to the first starting water temperature and the set low speed to the vehicle controller, so that the vehicle controller sends a dragging instruction to the motor in response to the low-speed dragging request flag, to instruct the motor to drag the engine to run at a low speed according to the target torque value. The oil pressure monitoring module 230 is configured to, during the process that the motor drags the engine and drives the oil pump to work, control the engine to prohibit fuel injection and ignition, and start the engine when detecting that the engine oil pressure rises to exceed a preset engine oil pressure threshold. The speed limiting module 240 is configured to, according to the engine oil temperature at the time of starting the engine, query a preset engine maximum speed limit table to obtain a target limit speed; wherein the engine maximum speed limit table describes the engine maximum speed under different engine oil temperatures; and limit the running speed of the engine below the target limit speed.
[0041] The specific functions and effects of the engine low-temperature start protection device can be explained by referring to other embodiments of the present specification, and will not be repeated here. Each module in the engine low-temperature start protection device can be implemented by software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in the engine controller in hardware form, or can be stored in the memory in the engine controller in software form, so as to be called and executed by the processor to perform the operations corresponding to each module.
[0042] The embodiments of the present specification also provide a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a computer to implement the engine low-temperature start protection method in any of the above embodiments.
[0043] The embodiments of the present specification also provide a computer program product comprising instructions which, when executed by a computer, cause the computer to implement the engine low-temperature start protection method in any of the above embodiments.
[0044] The embodiments of the present specification also provide an engine controller comprising a memory and a processor, the memory having a computer program stored therein, the computer program being executed by the processor to implement the engine low-temperature start protection method in any of the above embodiments.
[0045] The embodiments of the present specification also provide a range-extended hybrid vehicle comprising the above engine controller.
[0046] In some embodiments, referring to Figure 3 , the engine controller can be a terminal, and its internal structure diagram can be as shown in Figure 3 . The engine controller comprises a processor, a memory, and a communication interface connected by a system bus. The processor of the engine controller is configured to provide computing and control capabilities. The memory of the engine controller comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The communication interface of the engine controller is configured to communicate with external terminals in a wired or wireless manner. The wireless manner can be achieved by WIFI, operator network, NFC (near field communication), or other technologies. The computer program is executed by the processor to implement the engine low-temperature start protection method.
[0047] It can be understood that the specific examples herein are only to help those skilled in the art better understand the embodiments of the present specification, and not to limit the scope of the present application.
[0048] It can be understood that, in various embodiments in the present specification, the size of the sequence number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments in the present specification.
[0049] It can be understood that the various embodiments described in the present specification can be implemented alone or in combination, and the embodiments in the present specification do not limit this.
[0050] Unless otherwise specified, all technical and scientific terms used in the embodiments of the present specification have the same meanings as understood by those skilled in the art of the technology of the present specification. The terms used in the present specification are only for the purpose of describing the specific embodiments and are not intended to limit the scope of the present specification. The term "and / or" used in the present specification includes any and all combinations of one or more of the related listed items. The singular forms "a", "an" and "the" used in the embodiments of the present specification and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0051] It can be understood that the processor of the embodiments of the present specification can be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method embodiments can be completed by the integrated logic circuit of hardware in the processor or the instruction in the form of software. The processor described above can be a general processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The disclosed methods, steps and logic block diagrams in the embodiments of the present specification can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present specification can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register or other mature storage medium in the art. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method.
[0052] It is appreciated that the memory in the embodiments of the present specification can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM). It should be noted that the memory of the system and method described herein is intended to include, but not limited to, these and any other suitable types of memory.
[0053] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in connection with the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present specification.
[0054] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.
[0055] The above is only a specific implementation of the present specification, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present specification, which should be covered within the protection scope of the present specification. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A method for protecting an engine from low-temperature starting, characterized in that, An engine controller for use in a vehicle engine, wherein the engine is tightly coupled to an electric motor; the method includes: Obtain the current initial start-up coolant temperature of the engine; If the initial start-up coolant temperature is lower than a preset coolant temperature threshold, a low-speed drag request flag and a target torque value corresponding to the initial start-up coolant temperature and the set low speed are sent to the vehicle controller, so that the vehicle controller responds to the low-speed drag request flag and sends a drag command to the motor, instructing the motor to drag the engine to operate at low speed according to the target torque value; During the process of the motor driving the engine and driving the oil pump, the engine is controlled to prevent oil injection and ignition, and the engine is started when the oil pressure of the engine is detected to rise above the preset oil pressure threshold. Based on the engine oil temperature at engine start, a preset engine maximum speed limit table is consulted to obtain the target limit speed; wherein, the engine maximum speed limit table describes the engine maximum speed at different engine oil temperatures; The operating speed of the engine is limited to below the target speed limit.
2. The engine low-temperature starting protection method according to claim 1, characterized in that, The target torque value is determined based on a pre-established engine low-temperature torque model, which describes the torque values corresponding to different water temperatures and different speeds. The engine low-temperature torque model is established in the following way: On a low-temperature powertrain test bench, the torque of multiple engine samples is scanned and measured at different water temperatures and engine speeds; the average value of the torque measured multiple times is taken, and a two-dimensional data model containing the correspondence between water temperature, engine speed and torque is constructed based on the average value. The torque referred to is the frictional torque.
3. The method according to claim 2, characterized in that, In the engine low-temperature torque model, any of the water temperatures is greater than or equal to -40°C and less than or equal to 0°C; or, any of the engine speeds is greater than or equal to 700 r / min.
4. The method according to claim 3, characterized in that, In the engine low-temperature torque model, the difference between adjacent water temperatures is less than 5°C, or the difference between adjacent engine speeds is less than 500 r / min.
5. The method according to claim 1, characterized in that, The set low speed is a speed set below the normal idle speed of the engine.
6. The method according to claim 1, characterized in that, In the engine maximum speed limit table, any of the oil temperatures is greater than or equal to -40°C and less than or equal to 0°C. The engine maximum speed corresponding to different oil temperatures is obtained through actual vehicle testing and calibration.
7. The method according to claim 1, characterized in that, The method further includes: If the initial start-up coolant temperature is higher than or equal to the preset coolant temperature threshold, the engine is started, and the target speed limit is obtained by querying the preset engine maximum speed limit table based on the engine oil temperature at start-up; wherein, the engine maximum speed limit table describes the engine maximum speed at different oil temperatures; The operating speed of the engine is limited to below the target speed limit.
8. An engine low-temperature starting protection device, characterized in that, An engine controller for use in a vehicle engine, wherein the engine is tightly coupled to an electric motor; the device includes: The water temperature acquisition module is used to acquire the current initial start water temperature of the engine; The low-speed operation control module is used to send a low-speed towing request flag and a target torque value corresponding to the initial start-up water temperature and the set low speed to the vehicle controller if the initial start-up water temperature is lower than a preset water temperature threshold. This causes the vehicle controller to send a towing command to the motor in response to the low-speed towing request flag, instructing the motor to tow the engine at low speed according to the target torque value. The oil pressure monitoring module is used to control the engine to prevent fuel injection and ignition during the process of the motor driving the engine and driving the oil pump, and to start the engine when the oil pressure of the engine is detected to rise to exceed the preset oil pressure threshold. The speed limiting module is used to query a preset engine maximum speed limit table based on the engine oil temperature when the engine starts, and obtain the target speed limit; wherein the engine maximum speed limit table describes the maximum engine speed at different oil temperatures; and to limit the engine operating speed below the target speed limit.
9. An engine controller, characterized in that, The system includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the engine low-temperature start protection method according to any one of claims 1 to 7.
10. A vehicle, characterized in that, The vehicle is a range-extended hybrid vehicle, and the vehicle includes the engine controller as described in claim 9.