A control method, a control system and a hybrid vehicle

Abstract

The application discloses a control method and system of a hybrid vehicle and the hybrid vehicle, and comprises the following steps: obtaining the temperature of an engine and the battery power of the hybrid vehicle; in the case that the temperature of the engine is less than or equal to a first preset temperature, and the battery power is greater than or equal to a first power threshold and less than or equal to a second power threshold, the control system controls the heating system to output the heating air to the intake manifold and controls the motor to drag the engine reversely, so that the heating air enters the engine through the intake manifold to preheat the intake manifold and the engine; after the temperature of the preheated engine is greater than or equal to a second preset temperature, the preheating process is stopped, and the engine is started. The application preheats the low-temperature engine by the heating air and cooperates with the motor to drag the engine reversely, so that the engine reaches the suitable temperature before starting, thereby improving the low-temperature starting reliability, controlling the preheating energy consumption in a reasonable range, and avoiding the additional loss caused by repeated starting.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more particularly to a control method, control system, and hybrid vehicle. Background Technology

[0002] In extremely low temperatures, gasoline's fluidity decreases significantly and its viscosity increases, making it difficult for the injected fuel to atomize fully, resulting in large-diameter droplets rather than a uniform mist. Simultaneously, the cold temperatures on metal surfaces such as intake valves, intake manifolds, and cylinder walls cause the injected fuel to condense rapidly, adhering to the pipe walls and forming a "wet wall" phenomenon, further reducing the amount of fuel actually participating in combustion. These factors combined result in a low air-fuel mixture entering the cylinder, meaning the mixture is too lean and difficult for the spark plug to ignite effectively, severely impacting the engine's starting reliability under extremely cold conditions. Therefore, improving fuel atomization during cold starts is a pressing issue that needs to be addressed. Summary of the Invention

[0003] This application provides a control method, control system, and hybrid vehicle for a hybrid electric vehicle, which solves the technical problem of poor engine starting reliability in low-temperature environments in the prior art and achieves the technical effect of improving engine starting performance under extremely cold conditions.

[0004] In a first aspect, this application provides a control method for a hybrid electric vehicle, applied to a hybrid electric vehicle including an engine, an intake manifold, an electric motor, and a heating system, the method comprising: The temperature of the engine and the battery charge of the hybrid vehicle are obtained. When the engine temperature is less than or equal to a first preset temperature, and the battery charge is greater than or equal to a first charge threshold and less than or equal to a second charge threshold, the heating system is controlled to output warm air to the intake manifold and the motor is controlled to reverse-drive the engine so that the warm air enters the engine through the intake manifold to preheat the intake manifold and the engine. After the engine is preheated to a temperature greater than or equal to a second preset temperature, the preheating process is stopped, and the engine is started, wherein the first preset temperature is less than the second preset temperature.

[0005] Secondly, this application provides a control method for a hybrid electric vehicle, applied to a hybrid electric vehicle including an engine, a throttle valve, an intake manifold, and a heating system, the method comprising: The temperature of the intake manifold and the battery charge of the hybrid vehicle are obtained. If the temperature of the intake manifold is less than or equal to the first preset temperature and the battery charge is greater than or equal to the first charge threshold and less than or equal to the second charge threshold, then the throttle valve is opened and the heating system is controlled to output warm air to the intake manifold so that the warm air passes through the intake manifold to preheat the intake manifold. After preheating the intake manifold to a temperature greater than or equal to a second preset temperature, the preheating process is stopped, and the engine is started, wherein the first preset temperature is less than the second preset temperature.

[0006] Thirdly, this application provides a control system for a hybrid electric vehicle, including a controller, an engine, an intake manifold, a motor, and a heating system. The controller is used to execute a control method for a hybrid electric vehicle provided in the first aspect, and outputs warm air through the heating system to preheat the intake manifold and the engine.

[0007] Fourthly, this application provides a control system for a hybrid electric vehicle, including a controller, an engine, a throttle valve, an intake manifold, and a heating system. The controller is used to execute a control method for a hybrid electric vehicle provided in the second aspect, and outputs warm air through the heating system to preheat the intake manifold.

[0008] Fifthly, this application provides a hybrid electric vehicle, including a control system for a hybrid electric vehicle as provided in the third or fourth aspect.

[0009] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: This embodiment of the application sets a preheating process that simultaneously satisfies the dual starting conditions of an engine temperature less than or equal to a first preset temperature and a battery charge level between a first and a second charge threshold. This ensures that when the temperature is acceptable, no unnecessary energy is consumed, and when the charge level is too low, preheating is not initiated to prevent excessive battery discharge, thus establishing a reasonable decision boundary between starting requirements and energy management. By controlling the heating system to output warm air to the intake manifold and simultaneously controlling the electric motor to reverse-drag the engine, the intake valves of the engine periodically open and close while it is rotating. Warm air is drawn into the combustion chamber when the intake valves are open and discharged when the exhaust valves are open, forming a continuous hot airflow circulation through the intake manifold and inside the combustion chamber. This directly heats key areas such as the intake valves, combustion chamber walls, and piston tops, which are fuel-wetted walls. Furthermore, since the engine does not inject fuel or burn during the reverse-drag process, the hot air is not affected by in-cylinder combustion, resulting in high thermal efficiency. By setting the preheating treatment's start temperature to a lower first preset temperature and the termination temperature to a higher second preset temperature, a hysteresis interval is formed between the two thresholds. This avoids frequent system starts and stops when the temperature fluctuates around a single threshold. Furthermore, using temperature attainment as the sole termination criterion ensures consistent preheating effects under different initial conditions. Through the combined effect of the aforementioned judgment conditions, heating methods, and termination mechanisms, this embodiment ensures that the engine reaches the thermal state required for reliable starting while limiting the electrical energy consumption of the preheating process to a reasonable range. This avoids additional energy loss and starting wear caused by repeated attempts after insufficient preheating leading to start-up failures. Thus, a comprehensive balance between starting reliability, energy economy, and component durability is achieved in low-temperature environments. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below only show some embodiments of the present invention. Those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0011] Figure 1 A schematic diagram of a hardware architecture for a hybrid electric vehicle provided in an embodiment of this application; Figure 2 A schematic diagram of another hardware architecture for a hybrid electric vehicle provided in an embodiment of this application; Figure 3 A schematic flowchart illustrating a control method for a hybrid electric vehicle provided in an embodiment of this application; Figure 4 This is a flowchart illustrating another control method for a hybrid electric vehicle provided in an embodiment of this application.

[0012] Figure label: 1-Air filter, 2-Intake pipe, 3-Turbocharger, 4-Decompression valve, 5-Intercooler, 6-Throttle body, 7-Temperature sensor, 8-Intake manifold, 9-Heater valve, 10-Heating element, 11-Intake valve, 12-Cylinder head, 13-Exhaust valve, 14-Exhaust pipe, 15-Piston, 16-Crankshaft, 17-Crankcase, 18-Oil pan, 19-Engine oil, 20-Preheating line, 21-Preheating line, 22-Heater valve, 23-Heater element. Detailed Implementation

[0013] This application provides a control method, control system, and hybrid vehicle for a hybrid electric vehicle, which solves the technical problem of poor engine starting reliability in low-temperature environments in the prior art and achieves the technical effect of improving engine starting performance under extremely cold conditions.

[0014] The technical solution of this application embodiment is to solve the above-mentioned technical problems, and the general idea is as follows: This embodiment of the application sets a preheating process that simultaneously satisfies the dual starting conditions of the engine temperature being less than or equal to a first preset temperature and the battery charge being between a first charge threshold and a second charge threshold. This ensures that when the temperature is acceptable, no unnecessary energy is consumed, and when the charge is too low, preheating is not initiated to prevent excessive battery discharge, thus establishing a reasonable decision boundary between starting requirements and energy management. By controlling the heating system to output warm air to the intake manifold 8 and simultaneously controlling the motor to reverse-drag the engine, the intake valve 11 is periodically opened and closed while the engine is rotating. Warm air is drawn into the combustion chamber when the intake valve 11 is open and discharged when the exhaust valve 13 is open, forming a continuous hot airflow circulation through the intake manifold 8 and the inside of the combustion chamber. This directly heats key areas such as the intake valve 11, the combustion chamber walls, and the top of the piston 15, which are fuel-wetted walls. Furthermore, since the engine does not inject fuel or burn during the reverse-drag process, the hot air is not affected by in-cylinder combustion, resulting in high thermal efficiency. By setting the preheating treatment's start temperature to a lower first preset temperature and the termination temperature to a higher second preset temperature, a hysteresis interval is formed between the two thresholds. This avoids frequent system starts and stops when the temperature fluctuates around a single threshold. Furthermore, using temperature attainment as the sole termination criterion ensures consistent preheating effects under different initial conditions. Through the combined effect of the aforementioned judgment conditions, heating methods, and termination mechanisms, this embodiment ensures that the engine reaches the thermal state required for reliable starting while limiting the electrical energy consumption of the preheating process to a reasonable range. This avoids additional energy loss and starting wear caused by repeated attempts after insufficient preheating leading to start-up failures. Thus, a comprehensive balance between starting reliability, energy economy, and component durability is achieved in low-temperature environments.

[0015] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0016] First, it should be clarified that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0017] This application provides a control method for a hybrid electric vehicle, which includes an engine, an intake manifold, an electric motor, and a heating system. The engine is either a port fuel injection engine or a direct injection engine.

[0018] The fundamental difference between port fuel injection engines and direct injection engines lies in the location of the injectors and the fuel injection target area. In a port fuel injection engine, the injector is installed in the intake manifold 8 or the intake port of the cylinder head 12. Fuel is injected onto the back of the intake valve 11 and into the intake port, where it pre-mixes with air during the intake stroke to form a combustible mixture, which then enters the cylinder through the intake valve 11. In a direct injection engine, the injector is directly mounted on the cylinder head 12, with the nozzle extending into the combustion chamber. Fuel is directly injected under high pressure into the combustion chamber during the compression or intake stroke, where it mixes with air inside the cylinder. Due to the different injection positions, intake manifold fuel injection is an external premixed combustion mode, where the mixture has good uniformity before entering the cylinder, but fuel evaporation depends on the airflow movement in the intake manifold and the heat of the intake valve 11; direct injection is an internal direct mixing combustion mode, where fuel evaporation depends on the compression heat in the combustion chamber and the tumble motion guided by the shape of the piston top 15. Its fuel injection pressure is much higher than that of intake manifold fuel injection, which can achieve stratified combustion and lean combustion, thereby improving thermal efficiency and fuel economy.

[0019] For port fuel injection engines, the injectors are installed in the intake manifold 8 or the intake port of the cylinder head 12. Fuel is injected onto the back of the intake valve 11 and the intake port wall area. In low-temperature environments, the temperature of the intake valve 11 and the intake port wall is extremely low, and the injected fuel cannot be fully atomized and evaporated. Some liquid fuel directly impacts and adheres to the inner wall of the intake port and the back of the intake valve 11, forming a liquid oil film. This phenomenon is called intake port wet wall (external wet wall). Simultaneously, due to the influence of the intake airflow, some of the liquid fuel adhering to the intake port will still enter the cylinder as droplets. During the compression stroke, these droplets impact the top of the piston 15 and the cylinder wall (i.e., the combustion chamber wall), which are also at a relatively low temperature, thus forming a secondary wet wall. This phenomenon is called combustion chamber wet wall (internal wet wall). Therefore, port fuel injection engines exhibit both external and internal wet wall phenomena simultaneously at low temperatures.

[0020] For direct injection engines, the injectors are directly mounted on the cylinder head 12, and the injector nozzles extend into the combustion chamber, injecting fuel directly into the combustion chamber at high pressure. At low temperatures, the top of the piston 15 and the cylinder wall surface within the combustion chamber are extremely cold. The high-pressure fuel jet directly impacts the top surface of the piston 15 and the cylinder wall surface near the injector, forming a liquid fuel coating layer—a phenomenon known as in-cylinder wet wall. Because the fuel does not pass through the intake manifold, direct injection engines do not have the intake manifold wet wall problem.

[0021] Therefore, the difference in the location of the wet walls between the two is that port fuel injection engines have both external and internal wet walls, while direct injection engines only have internal wet walls. Although the degree of internal wet wall in a port fuel injection engine is usually weaker than that of its external wet wall, this dual wet wall characteristic still makes the air-fuel mixture formation problem during cold starts more complex than that of a direct injection engine.

[0022] Since intake manifold fuel injection engines have both external and internal wet walls, while direct injection engines only have internal wet walls, and the two have different physical characteristics in terms of the location and severity of the wet walls, this application provides two different control methods for the characteristics of these two types of engines.

[0023] One method involves controlling the heating system to output warm air to the intake manifold 8, while simultaneously controlling the electric motor to reverse-drive the engine. This allows the warm air to pass sequentially through the intake manifold 8 and the engine interior, preheating both the intake manifold walls and the combustion chamber walls, corresponding to subsequent steps S31-S33. Since this method acts on both the intake manifold and the combustion chamber, it can simultaneously improve both the wet walls of the intake manifold (external wet walls) and the wet walls of the combustion chamber (internal wet walls). Therefore, this approach is suitable for both intake manifold fuel injection engines (simultaneously addressing dual wet walls) and direct injection engines (addressing internal wet walls).

[0024] Another method (corresponding to subsequent steps S41-S43) involves opening the throttle valve 6 and controlling the heating system to output warm air to the intake manifold 8. This warm air preheats the intake manifold by passing through the intake manifold 8. This method only heats the intake manifold walls and the area behind the intake valve 11, specifically addressing the fuel adhesion problem caused by wet intake manifold walls. Of course, steps S31-S33 can be executed after this method; the specific process will be explained later and will not be elaborated here. Since direct injection engines do not have a wet intake manifold wall problem, and their in-cylinder wet walls are located inside the combustion chamber, simply preheating the intake manifold cannot effectively heat the top of the piston 15 and the cylinder wall. Therefore, this method is only applicable to port fuel injection engines to improve their external wet wall problem. While the in-cylinder wet wall problem of the port fuel injection engine itself is not directly addressed by this method, the improvement of the external wet wall significantly enhances its low-temperature start-up performance. Through the above two differentiated designs, the embodiments of this application can flexibly select the appropriate preheating strategy according to different engine types, and achieve the best low-temperature start-up improvement effect while reducing energy consumption and costs.

[0025] This application provides two hybrid vehicle structures, which can be found in the following examples. Figure 1 and Figure 2 As shown, the hybrid electric vehicle includes an air filter 1, an intake manifold 2, a turbocharger 3, a pressure relief valve 4, an intercooler 5, a throttle body 6, an intake manifold 8, heater valves 9 and 22, heating elements 10 and 23, preheating pipes 20 and 21, a temperature sensor 7, a cylinder head 12, an intake valve 11, an exhaust valve 13, an exhaust pipe 14, a crankcase 17, pistons 15, a crankshaft 16, and an oil pan 18. The outlet of the air filter 1 is connected to the inlet of the intake manifold 2, the outlet of the intake manifold 2 is connected to the inlet of the turbocharger 3, the outlet of the turbocharger 3 is connected to the inlet of the intercooler 5, the outlet of the intercooler 5 is connected to the inlet of the throttle body 6, and the outlet of the throttle body 6 is connected to the inlet of the intake manifold 8. The air inlet of the pressure relief valve 4 is connected to the pipeline between the intercooler 5 and the throttle valve 6, and the air outlet of the pressure relief valve 4 is connected to the intake pipe 2.

[0026] The heating system includes heating elements 10 and 23, which include a heating core and / or an electric heater.

[0027] The warm air outlets of heating elements 10 and 23 are connected to the air inlets of warm air valves 9 and 22 via preheating pipes 20 and 21. The air outlets of warm air valves 9 and 22 are connected to the preheating inlets of intake manifold 8 via preheating pipes 20 and 21. A temperature sensor is installed on intake manifold 8 (not located on...). Figure 1 and Figure 2(As shown in the figure), it is used to detect the temperature inside the intake manifold 8. The outlet of the intake manifold 8 is connected to the intake passage of the cylinder head 12. The intake passage of the cylinder head 12 is connected to the combustion chamber through the intake valve 11. The combustion chamber is connected to the exhaust passage of the cylinder head 12 through the exhaust valve 13. The exhaust passage of the cylinder head 12 is connected to the intake port of the exhaust pipe 14.

[0028] The cylinder head 12 is fixedly connected to the crankcase 17. The crankcase 17 houses the piston 15 and the crankshaft 16. The piston 15 is located inside the cylinder of the crankcase 17 and is driven by the crankshaft 16. An oil pan 18 is located at the bottom of the crankcase 17, containing engine oil 19. The motor is driven by the crankshaft 16 and drives the crankshaft 16 to rotate, thereby causing the piston 15 to reciprocate within the cylinder. When the throttle valve 6 is closed, the reciprocating motion of the piston 15 creates negative pressure in the intake manifold 8, drawing the warm air generated by the heating elements 10 and 23 into the intake manifold 8 via the heater valves 9 and 22 and the preheating pipes 20 and 21, and into the combustion chamber.

[0029] Figure 1 The preheating pipe 20 is directly connected to the intake manifold 8. Alternatively, the preheating pipe 21 can also be connected to the pipe between the intercooler 5 and the throttle body 6. For details, please refer to [reference needed]. Figure 2 As shown.

[0030] The first method provided in the embodiments of this application can be suitable for Figure 1 The structure shown can also be adapted to Figure 2 The structure shown, and the second method provided in this application embodiment, are only suitable for... Figure 1 The structure is shown. Both the first and second methods can be executed by the controller of the hybrid vehicle. Specifically, the controller can be the vehicle control unit (VCU), or it can be executed collaboratively by the engine control unit (ECU) and the vehicle control unit. This application does not specifically limit this approach.

[0031] The first method is explained below, and it includes steps S31-S33, for details. Figure 3 As shown: Step S31: Obtain the temperature of the engine and the battery charge of the hybrid vehicle; Step S32: When the engine temperature is less than or equal to the first preset temperature and the battery charge is greater than or equal to the first charge threshold and less than or equal to the second charge threshold, the heating system is controlled to output warm air to the intake manifold 8 and the motor is controlled to reverse drive the engine so that the warm air enters the engine through the intake manifold 8 to preheat the intake manifold 8 and the engine. Step S33: After preheating the engine to a temperature greater than or equal to the second preset temperature, stop the preheating process and start the engine, wherein the first preset temperature is less than the second preset temperature.

[0032] Regarding step S31, the temperature of the engine and the battery charge of the hybrid vehicle are obtained.

[0033] The engine temperature can be obtained using a temperature sensor 7 located within the combustion chamber, which directly detects the temperature inside the combustion chamber. Alternatively, the engine temperature can also be obtained using a temperature sensor located within the intake manifold 8. Since the gas temperature within the intake manifold 8 can reflect the engine's thermal state to some extent, detecting the intake manifold 8 temperature can also be used to characterize the engine temperature. It should be noted that the temperature sensor 7 located within the combustion chamber is... Figure 1 and Figure 2 The sensor is schematically shown in the figure, while the temperature sensor located in the intake manifold 8 is not shown in the figure, but its installation position and detection principle are well known in the art.

[0034] The battery power is obtained as follows: the battery management system (BMS) of the hybrid vehicle monitors the voltage, current, temperature, and other state parameters of the power battery in real time, and calculates the current battery power using a state of charge (SOC) estimation algorithm. The controller reads this battery power information through a communication connection with the battery management system, for example, by receiving the battery power signal sent by the battery management system via the Controller Area Network (CAN) bus. This application embodiment does not limit the specific battery power estimation algorithm; methods known in the art, such as the ampere-hour integration method, Kalman filtering method, or equivalent circuit model method, can all be used.

[0035] In other words, "acquiring the engine temperature" and "acquiring the battery charge" in step S31 refer to the controller reading the detection results from the corresponding sensors or management system, rather than the physical process of the controller itself performing temperature measurement or charge estimation. Through this acquisition method, the controller can accurately grasp the thermal state of the engine and the energy storage state of the power battery before starting in low temperatures, thus providing a reliable data basis for subsequent judgments on whether preheating conditions are met.

[0036] Regarding step S32, if the engine temperature is less than or equal to a first preset temperature, and the battery charge is greater than or equal to a first charge threshold and less than or equal to a second charge threshold, then the heating system is controlled to output warm air to the intake manifold 8 and the motor is controlled to reverse-drive the engine, so that the warm air enters the engine through the intake manifold 8 to preheat the intake manifold 8 and the engine.

[0037] The first preset temperature is greater than the engine's minimum operating temperature and less than or equal to -10°C. -10°C is a critical temperature value determined through extensive calibration tests. When the ambient temperature or engine temperature is above -10°C, the engine's fuel atomization effect is acceptable, and the fuel injected by the injector can form a relatively uniform combustible mixture. The engine can start normally using the normal fuel injection amount without additional preheating. When the engine temperature is below or equal to -10°C, the fuel viscosity increases significantly, the atomization quality deteriorates sharply, and fuel condensation and adhesion on the intake manifold walls and the back of the intake valve 11 are severe, resulting in a significant reduction in the effective amount of fuel entering the cylinder for combustion. At this time, without preheating, the engine will be difficult to start or may even fail to start. Therefore, setting the first preset temperature to less than or equal to -10°C can accurately distinguish the temperature boundary where preheating is required for starting, and avoids unnecessary energy consumption for preheating within the temperature range where the engine can start normally. This optimizes the vehicle's energy management while ensuring starting reliability.

[0038] The first energy threshold is greater than or equal to 14%, and the energy span between the first energy threshold and the second energy threshold is negatively correlated with the battery capacity of the hybrid vehicle's power battery. The second energy threshold is 17%-25%.

[0039] The first battery charge threshold is set to be greater than or equal to 14%. This is based on the fact that when the battery charge is below this threshold, it indicates that the battery's energy storage state is already at a low level. If driving continues in pure electric mode or relying solely on the electric motor, there is a risk of over-discharge. In this case, the engine needs to be started to drive the generator to charge the battery. Mainstream automakers typically set this threshold at around 15%. The fundamental reason is that the battery management system's state of charge estimation has a certain degree of error. Setting the threshold above 14% ensures sufficient safety margin even when the actual battery charge may be lower than the displayed charge, preventing damage to the battery's lifespan or vehicle power interruption due to over-discharge.

[0040] The second energy threshold is negatively correlated with battery capacity, and can be set between 17% and 25%. This is because when the battery level is higher than the first energy threshold but lower than the second, the battery still has sufficient energy reserves to support the vehicle's operation in pure electric mode for a period of time without starting the engine. If the battery capacity is large, such as in plug-in hybrid electric vehicles equipped with large-capacity batteries, even a 2% energy gap (i.e., the first energy threshold is 15% and the second energy threshold is 17%) is enough to sustain the vehicle for several kilometers or even longer in pure electric mode. During this period, the engine remains off, and the heating system has ample time to preheat the intake manifold and engine. If the battery capacity is small, a wider energy range needs to be reserved (e.g., setting the second energy threshold to 25%) to ensure sufficient energy to support the heating system for a sufficiently long preheating time before the engine starts. Therefore, this negative correlation between the second energy threshold and battery capacity allows vehicles with different battery capacities to obtain a reasonable preheating energy window, ensuring effective preheating while avoiding excessive energy consumption that could limit the vehicle's subsequent driving capability.

[0041] Furthermore, the warm air outlet of the heating system is connected to the intake manifold 8 via preheating pipes 20 and 21 equipped with warm air valves 9 and 22 (the connection to the intake manifold 8 can be direct or via the connection between the throttle valve 6 and the intercooler 5). Controlling the heating system to output warm air to the intake manifold 8 includes: The heating system is activated to generate warm air, and the heating valves 9 and 22 are opened so that the heating system outputs warm air to the intake manifold 8.

[0042] In this embodiment, the warm air generated by the heating elements 10,23 of the heating system is delivered to the intake manifold 8 via preheating pipes 20,21 connected to the warm air outlet. Warm air valves 9,22 are installed on the preheating pipes 20,21, serving as switching elements to control the flow of warm air. When preheating is required, the controller issues a control command to activate the heating elements 10,23 in the heating system to generate warm air, and simultaneously opens the warm air valves 9,22, thus opening the heating pipes. The warm air then flows along the preheating pipes 20,21 to the intake manifold 8.

[0043] It should be noted that the connection between the preheating pipe 20 and the intake manifold 8 can be such that the outlet of the preheating pipe 20 is directly connected to the reserved interface of the intake manifold 8, for example... Figure 1 As shown; alternatively, the outlet of the preheating pipe 21 can be connected to the intake pipe between the throttle valve 6 and the intercooler 5, utilizing the existing connection between the intake pipe and the intake manifold 8, so that warm air enters the intake manifold 8 through the throttle valve 6, as shown. Figure 2 As shown. Both of the above-mentioned connection methods fall within the scope of the embodiments of this application.

[0044] It is important to note that the path of the warm air generated by the heating system into the intake manifold 8 via preheating pipes 20 and 21 depends on the connection point of the preheating pipes 20 and 21. When the preheating pipe 20 is directly connected to the intake manifold 8 (i.e.... Figure 1 As shown), the warm air enters the intake manifold 8 directly. In this connection method, the throttle valve 6 needs to be closed during the process of the motor reverse-dragging the engine. A strong negative pressure is formed inside the intake manifold 8. This negative pressure acts as a driving force to continuously draw the warm air into the intake manifold 8 and further into the engine through the intake valve 11.

[0045] When the preheating pipe 21 is connected to the intake pipe between the intercooler 5 and the throttle valve 6 (i.e.) Figure 2 As shown), the warm air flows to the throttle valve 6 through this section of the intake pipe. In this connection method, the throttle valve 6 is in the open state during the process of the electric motor reverse-dragging the engine. The warm air enters the intake manifold 8 through the throttle valve 6, and then enters the engine through the intake valve 11.

[0046] Both access methods can preheat the intake manifold 8 and the engine with warm air. The difference lies in the different paths the warm air takes before entering the intake manifold 8 and the different states of the corresponding throttle valve 6. In practical applications, the appropriate method can be flexibly chosen based on the overall vehicle piping layout and structural design. Regardless of the method used, the warm air ultimately enters the engine through the intake valve 11, heating the intake manifold walls, the back of the intake valve 11, the top of the piston 15, and the cylinder walls, thereby preheating the intake manifold 8 and the engine.

[0047] However, it should be noted that when the preheating pipe 21 adopts... Figure 2 The connection method shown, where warm air flows from the intercooler 5 to the throttle valve 6 via the intake pipe between the intercooler 5 and the throttle valve 6, under the condition of the electric motor reverse-drafting the engine and the throttle valve 6 being open, the negative pressure in the intake manifold 8 not only draws in warm air through the preheating pipe 21, but also draws in a large amount of ambient cold air through the intake pipe upstream of the throttle valve 6 (including the intake pipes of the intercooler 5, turbocharger 3, and air filter 1). The ambient cold air and warm air merge at the throttle valve 6 and enter the intake manifold 8 together, resulting in the actual temperature of the gas entering the engine being lower than the temperature of the warm air output by the heating system. This reduces preheating efficiency and wastes heat to some extent. Therefore, Figure 2 While the connection method shown offers greater flexibility in the overall vehicle piping layout, its preheating efficiency is relatively lower due to the issue of cold air mixing. Figure 1 The design shown depicts a preheating pipe 20 directly connected to the intake manifold 8. In practical applications, if the vehicle's engine compartment space and pipe routing permit, this design should be preferred. Figure 1 The direct connection method shown achieves higher heat utilization.

[0048] In summary, this embodiment firstly achieves precise and controllable heating supply by setting the heater valves 9 and 22 and opening them when needed, avoiding energy waste caused by continuous heating output when preheating is not required. Secondly, the multiple connection methods between the preheating pipes 20 and 21 and the intake manifold 8 provide flexibility for the overall vehicle layout. Different models can choose the most suitable connection scheme according to the engine compartment space and pipe routing, reducing the cost of structural modifications. Thirdly, when the preheating pipes 20 and 21 are directly connected to the intake manifold 8 and the throttle valve 6 is closed, the negative pressure generated by the intake manifold 8 itself is used as the heating power; when the preheating pipes 20 and 21 are connected between the intercooler 5 and the throttle valve 6 and the throttle valve 6 is open, the suction effect generated by the piston 15 movement during engine reverse drag introduces the heating air into the intake manifold 8. Neither method requires additional fans or superchargers, simplifying the system structure and reducing power consumption. Finally, the warm air is directly input into the intake manifold 8 and enters the engine, which can directly heat the fuel wet wall areas such as the intake manifold wall, the back of the intake valve 11, and the combustion chamber wall. This effectively increases the temperature of these areas before cold starts, thereby significantly improving fuel atomization conditions, reducing fuel condensation and adhesion, ensuring that the engine can obtain a suitable combustible mixture when starting, and improving the reliability of cold starts.

[0049] Regarding step S33, after preheating the engine to a temperature greater than or equal to the second preset temperature, the preheating process is stopped, and the engine is started, wherein the first preset temperature is less than the second preset temperature.

[0050] The second preset temperature is greater than 0℃ and less than or equal to 10℃. The value of the second preset temperature, ranging from 0℃ (excluding 0℃) to 10℃, needs to be analyzed more accurately based on the actual operating conditions of low-temperature startup. During preheating in extremely cold environments, although warm air continuously enters the engine during motor reverse drag, heating the intake manifold wall, the back of the intake valve 11, and the combustion chamber wall, causing the temperature in these areas to gradually rise above 0℃, fresh cold air is immediately drawn into the cylinder after preheating ends and the engine is started. Due to the extremely low ambient temperature, the temperature of this cold air is much lower than the wall temperature. During the intake stroke, the cold air rapidly flows through the intake manifold and combustion chamber, forcibly cooling the already preheated walls, causing the wall temperature to drop significantly shortly after startup.

[0051] If the second preset temperature is lower than or equal to 0℃, the wall temperature will already be below freezing when preheating stops. Further cooling by the cold air after startup will cause the wall temperature to continue to drop, potentially falling to -10℃ or even lower. At this point, the thermal state established during preheating is almost completely negated, and the wall temperature returns to the temperature range where condensation and wet walls are most severe. Fuel will still adhere extensively to the back of the intake valve 11, the intake manifold wall, and the combustion chamber wall after injection, significantly reducing or even completely negating the effectiveness of preheating and making engine starting reliability impossible. Therefore, setting the lower limit of the second preset temperature above 0℃ ensures that even if the wall temperature drops to some extent after startup due to the flow of cold air, the temperature after the drop will remain near or above 0℃ because the preheating endpoint temperature is already above freezing. This prevents significant condensation and wet walls from forming after fuel injection due to the wall temperature being below freezing, thus ensuring the preheating effect continues until the startup process is successfully completed.

[0052] On the other hand, the second preset temperature is set to no more than 10°C because the preheating process requires the consumption of battery power and heat generated by the heating system. Setting the target temperature too high would significantly prolong the preheating time and greatly increase power consumption. Furthermore, once the wall temperature exceeds 10°C, the effect of further increasing the temperature on improving fuel atomization becomes less pronounced, with diminishing marginal returns, while the power consumed during preheating continues to increase. This could potentially affect the vehicle's subsequent driving range and power performance due to excessive power consumption. Therefore, the range of 0°C (excluding 0°C) to 10°C is an optimal range determined after fully considering the cooling margin of cold air, starting reliability, and a reasonable balance between energy consumption.

[0053] After preheating reaches the second preset temperature, the preheating process is stopped by closing the heater valves 9 and 22 and stopping the motor from reversing the engine. Closing the heater valves 9 and 22 serves two purposes: first, it cuts off the heater path between the heating system and the intake manifold 8, preventing the continued intake of heater air after preheating from causing overheating of the engine and unnecessary heat loss and energy waste; second, after preheating is complete and the engine is started, the engine needs to draw in fresh air to support combustion. If the heater valves 9 and 22 are open, the preheating pipes 20 and 21 effectively form a bypass branch on the intake manifold 8. The negative pressure generated during the engine's intake stroke will draw some air in through this bypass branch, instead of all of it entering the cylinder through the air filter 1 and the intake pipes. This will cause the actual amount of fresh air participating in combustion to deviate from the calibrated value, affecting the precise control of the air-fuel ratio, and potentially causing an unstable or even failed start-up process. After closing the heater valves 9 and 22, the preheating pipes 20 and 21 are cut off, and the bypass passage between the intake manifold 8 and the heating system is severed. All the air drawn in during engine startup enters the intake manifold 8 through the normal intake channels (air filter 1, intake pipe 2, turbocharger 3, intercooler 5, throttle valve 6) and is distributed to each cylinder, ensuring the accuracy and consistency of the intake air volume during startup. The function of stopping the electric motor's reverse-draft engine is to end the passive rotational drive of the engine, bringing it from an externally driven state to a stationary state, preparing it for subsequent normal startup.

[0054] It should be noted that closing the heater valves 9 and 22 and stopping the motor reverse drag are necessary operations at the end of the preheating process. However, whether the heating system itself is shut down depends on the current operating requirements of the hybrid vehicle. If the passenger compartment requires heating, or other components such as the power battery need to be heated by the heat generated by the heating system, the heating system will continue to operate, with only the heating passage to the intake manifold 8 being cut off by closing the heater valves 9 and 22. If no part of the vehicle requires heating, the heating system will be shut down to further reduce energy consumption. The above-mentioned differentiated shutdown strategy ensures both the integrity of the intake passage and the accuracy of the air-fuel ratio during engine startup, while also taking into account the comprehensive needs of vehicle thermal management, avoiding the failure to meet passenger comfort or battery heating requirements due to a single shutdown strategy.

[0055] During the preheating process in step S32, the temperature sensor continuously monitors the engine temperature and transmits the results to the controller in real time. The controller compares the current engine temperature with a pre-stored second preset temperature. When the controller determines that the current engine temperature is greater than or equal to the second preset temperature, it indicates that the preheating has reached the target level and the engine is ready for reliable start-up. At this point, the controller first issues a command to close the heater valves 9 and 22, cutting off the heater supply path; then it issues a command to stop the motor from reverse-dragging the engine, causing the engine crankshaft 16 to stop rotating. After the above two operations are completed, the controller issues a start command, controlling the starter motor or having the motor drive the engine crankshaft 16 to rotate to the start speed, and controlling the injectors to inject fuel and the spark plugs to ignite, allowing the engine to enter a self-running state and completing the start-up process. Throughout the process, the first preset temperature is lower than the second preset temperature, ensuring a reasonable hysteresis range between the start and stop conditions of the preheating process, avoiding frequent start-stop cycles due to temperature fluctuations.

[0056] Through the above process, this embodiment of the application can terminate preheating in a timely manner after the engine temperature reaches a threshold sufficient to support reliable starting, avoiding starting failure due to insufficient preheating time and unnecessary energy consumption due to excessive preheating time. When terminating preheating, the sequential operation of closing the heater valves 9 and 22 and stopping the motor reverse drag ensures that the heater path is cut off while the engine returns to a standstill, providing a clear boundary for subsequent starting. Since the heater system can flexibly choose to remain operational or shut down according to other vehicle heat demands, this embodiment of the application can, while achieving the engine preheating target, control the electrical energy consumed during preheating within a reasonable range, while retaining the ability to supply heating to the passenger compartment or other components. This balances engine starting reliability, vehicle energy economy, and passenger comfort in low-temperature environments. The differentiated setting between the first and second preset temperatures provides clear starting and termination boundaries for the preheating process, avoiding the instability of the system repeatedly switching near the critical temperature under a single threshold, allowing the preheating process to be completed in one go and the engine to start successfully on the first attempt.

[0057] In summary, based on the above-described operations of obtaining engine temperature and battery charge, the embodiments of this application, since the initiation of preheating requires the simultaneous fulfillment of the dual conditions of the temperature being lower than or equal to a first preset temperature and the battery charge being between a first charge threshold and a second charge threshold, can avoid unnecessary preheating consumption within the temperature range that has not yet fallen to the point of affecting initiation. At the same time, it does not initiate preheating when the charge is too low to prevent excessive battery discharge, thereby establishing a reasonable decision boundary between initiation reliability and power management.

[0058] Based on the above-described operation of controlling the heating system to output warm air to the intake manifold 8 while simultaneously controlling the motor tows the engine, the reciprocating motion of the piston 15 when the engine is rotating due to the motor's reverse drag causes the intake valve 11 to open and close periodically. Warm air is drawn into the combustion chamber during the opening of the intake valve 11 and discharged during the opening of the exhaust valve 13, forming a continuous hot airflow circulation through the intake manifold 8 and the combustion chamber. This circulation allows the hot air to not only heat the walls of the intake manifold 8 but also directly contact and heat key areas such as the intake valve 11, the combustion chamber walls, and the top of the piston 15, which are fuel-wetted walls. Its heating efficiency is significantly better than the scheme that only preheats the intake manifold 8 while the engine is stationary. Furthermore, since the engine does not inject fuel or burn fuel during the motor reverse drag operation, the warm air is not disturbed by in-cylinder combustion when flowing through the combustion chamber. The hot air can directly act on the surfaces that need heating with minimal heat loss; therefore, this scheme has a relatively high thermal utilization rate.

[0059] Based on the above operation of stopping preheating and starting the engine after the engine temperature is greater than or equal to the second preset temperature, since the preheating process starts when the temperature is less than or equal to the lower first preset temperature and ends when the temperature is greater than or equal to the higher second preset temperature, the difference between the two thresholds constitutes a hysteresis interval. This avoids the instability and extra energy consumption caused by frequent start-stop operations of the preheating process when the temperature fluctuates around a single threshold. At the same time, the establishment of this termination condition ensures that the preheating process ends only when the target temperature is reached, rather than based on a fixed time or fixed energy consumption. Under different initial temperatures, environmental conditions, and heating power, the preheating process can continue until the target temperature is reached, thus ensuring the consistency of the preheating effect.

[0060] From the combined relationships of the above operations, the entire process is interconnected: first, temperature and power consumption are obtained as the entry point; then, the dual methods of warm air output and motor reverse drag are used as the execution path; and finally, the temperature reaches the target as the exit condition. This process ensures that the engine reaches the thermal state required for reliable starting while limiting the energy consumption of the preheating process to a reasonable range. It also avoids the additional energy loss and wear caused by repeated starting attempts due to insufficient preheating, thus achieving a comprehensive balance between starting reliability, energy economy, and component durability in low-temperature environments.

[0061] Furthermore, after obtaining the engine temperature and the battery charge of the hybrid vehicle, the method further includes: If the engine temperature is less than or equal to the first preset temperature and the battery charge is less than the first charge threshold, then the engine injectors are controlled to increase the fuel injection quantity and start the engine.

[0062] The process of controlling the engine's injectors to increase the fuel injection quantity and start the engine includes: Before starting the engine, control the engine's injectors to inject fuel N times, and then control the engine to start, where N is a positive integer less than 4; or, Control the engine to start and extend the fuel injection duration of the injector.

[0063] In other words, this application also provides another low-temperature start control method, applicable to situations where the battery charge is below a first charge threshold. Specifically, after acquiring the engine temperature and battery charge, if the controller determines that the engine temperature is less than or equal to a first preset temperature, it indicates that the engine is currently in a low-temperature state requiring thermal assistance for reliable start-up. However, if the battery charge is below the first charge threshold, it means that the remaining charge of the power battery is insufficient to support the energy consumption for preheating via the heating system. Forcibly starting the heating system could lead to excessive battery discharge or even affect the vehicle's basic driving capability. In this case, the controller controls the engine's injectors to increase the fuel injection quantity and start the engine. By enriching the air-fuel mixture, it compensates for the loss of effective fuel quantity caused by poor fuel atomization and wetted walls in low-temperature environments, thereby achieving a cold start of the engine without consuming additional electrical energy.

[0064] Regarding the specific implementation method of controlling the injector to increase the fuel injection quantity, this application provides two optional implementation methods.

[0065] The first method involves controlling the fuel injectors to pre-inject fuel N times before starting the engine, and then controlling the starter motor or a motor to drive the engine to start, where N is a positive integer less than 4, i.e., injecting once, twice, or three times. The principle involves two aspects: First, the pre-injected fuel is already present in the intake manifold. Compared to the method of injecting fuel while starting, this fuel has a longer evaporation time, allowing more fuel to change from liquid to gaseous state before starting, thus pre-forming a highly concentrated combustible mixture in the intake manifold. When starting begins, this evaporated gaseous fuel enters the cylinder with the intake airflow, significantly increasing the proportion of fuel vapor in the initial mixture. Second, the unevaporated portion of the pre-injected fuel adheres to the intake manifold walls and the back of the intake valve 11, forming an oil film. During subsequent starting, the intake airflow can gradually peel off this adhered fuel and carry it into the cylinder to participate in combustion, further increasing the total amount of fuel actually burned in the initial stage of starting.

[0066] The second method is to control the engine start-up and extend the fuel injection duration of the injectors. That is, during the process of the engine being driven and rotated, the duration of a single injection by the injectors is extended to exceed the injection duration under normal starting conditions. By extending the injection pulse width, the amount of fuel injected per unit time is increased, so that the air-fuel mixture concentration formed under the same intake air volume is higher than that at normal temperature start-up, thus overcoming the problems of low fuel evaporation rate and insufficient effective fuel quantity at low temperatures.

[0067] Both of the above methods can achieve the goal of increasing the effective amount of fuel actually entering the cylinder under low-temperature conditions. The specific method used can be determined by the controller based on the engine type, current temperature, and calibration data. This application does not limit this. It should be noted that the above-mentioned control method for increasing fuel injection volume is an alternative solution used when the battery power is insufficient to support heater preheating. Its technical essence is to cope with the difficulty of starting at low temperatures through fuel compensation, without relying on external heat energy input. Therefore, it is suitable for extreme operating conditions with low battery power.

[0068] Furthermore, for operating conditions where the engine temperature exceeds a first preset temperature, this embodiment adopts a direct engine start control method. Specifically, after acquiring the engine temperature and battery charge, if the controller determines that the engine temperature is higher than the first preset temperature, it indicates that the current engine thermal state has not yet reached a critical level affecting fuel atomization and mixture formation. The temperatures of the intake manifold wall, the back of the intake valve 11, and the combustion chamber wall are still within the range that allows the injected fuel to maintain a basic atomization and evaporation level. At this time, there is no need for auxiliary means such as preheating with warm air or increasing the fuel injection quantity. The engine can form a combustible mixture with a concentration that meets the ignition requirements using a conventional fuel injection strategy. Based on this, the controller issues a start command, controls the starter motor or the motor to drive the engine to the start speed, and simultaneously controls the fuel injector to inject fuel according to the fuel injection pulse width corresponding to the normal temperature start condition, and controls the spark plug to perform ignition at the preset ignition time, so that the engine enters the self-running state. The above-mentioned direct start control method simplifies the start process under the premise of meeting the start conditions, avoids unnecessary power consumption and preheating waiting time, and enables the engine to complete the start process with maximum efficiency under acceptable operating conditions. This branch, together with the two processing methods mentioned above when the temperature is less than or equal to the first preset temperature (i.e., using warm air preheating when the battery power is moderate, and increasing the amount of fuel injection when the battery power is low), constitutes a complete low-temperature start-up control strategy covering different temperature and different power combinations, enabling the embodiments of this application to adaptively select the most suitable start-up method according to the actual temperature and power conditions.

[0069] After explaining the two handling methods when the temperature is less than or equal to the first preset temperature (using warm air preheating when the battery power is moderate, and increasing the fuel injection when the battery power is low), starting the engine directly when the temperature is greater than the first preset temperature, and pure electric operation when the battery power is sufficient and there is no need to start the engine, in order to more clearly illustrate the overall application logic of the above branches in actual working conditions, the following is an illustrative example of a complete vehicle power-on and start-up process.

[0070] Assuming the current ambient temperature is -15℃ and the vehicle is in a parked state, the driver presses the brake pedal and the start button. After receiving the power-on signal, the vehicle controller first obtains the current engine temperature through the temperature sensor located in the combustion chamber or intake manifold 8, and at the same time obtains the current power charge of the power battery through the battery management system.

[0071] If the obtained engine temperature is less than or equal to the first preset temperature (e.g., -10°C), it indicates that the engine is in a low-temperature state requiring thermal assistance for reliable starting. At this time, the controller further judges the battery charge. If the battery charge is lower than the first charge threshold (e.g., below 14% or 15%), it indicates that the remaining battery charge is insufficient to support the power consumption required for preheating. The controller then chooses not to initiate preheating and instead directly controls the engine's injectors to increase the fuel injection quantity and start the engine. Specifically, this can be achieved by pre-injecting fuel 1 to 3 times before starting to prolong the evaporation time and increase the proportion of fuel vapor in the air-fuel mixture, or by extending the injection duration during the starting process to enrich the air-fuel mixture, thereby completing the low-temperature start without consuming additional power. This is the first branch.

[0072] If the obtained engine temperature is also less than or equal to the first preset temperature, but the battery charge is higher than the second charge threshold (e.g., charge greater than 25%), it indicates that the battery has sufficient energy storage. At this time, the vehicle does not need engine output power (e.g., only low-voltage electricity or short-distance low-speed pure electric driving is required). The controller chooses not to start the engine or perform preheating, but instead controls the vehicle to operate in pure electric mode, driven by the electric motor, with the engine remaining off. During pure electric driving, the controller continuously monitors the engine temperature. When the engine temperature drops to below or equal to the first preset temperature due to natural heat radiation or changes in operating conditions, and the battery charge drops back to the range between the first and second charge thresholds due to driving consumption, the controller then initiates the preheating process. It first outputs warm air to the intake manifold 8 through the heating system and controls the electric motor to reverse-drive the engine for preheating. The engine is then started after the temperature rises to the second preset temperature. This is the second branch.

[0073] If the obtained engine temperature is less than or equal to the first preset temperature, and the battery charge is between the first and second charge thresholds (e.g., between 15% and 20%), it indicates that the engine needs preheating assistance and the battery has sufficient charge to support the energy consumption of the preheating process. The controller then performs preheating: it controls the heating system to output warm air to the intake manifold 8, and simultaneously controls the motor to reverse-drive the engine, allowing the warm air to enter the engine through the intake manifold 8 to heat the intake manifold walls, the back of the intake valve 11, and the combustion chamber walls. Once the engine temperature rises to greater than or equal to the second preset temperature (e.g., 0°C to 10°C, excluding 0°C), the preheating process is stopped and the engine is started. This is the third branch.

[0074] If the obtained engine temperature is higher than the first preset temperature (e.g., above -10°C), it indicates that the current engine thermal condition is acceptable, and fuel atomization and mixture formation are not severely affected by the low temperature. The controller will not perform any preheating or enrichment injection measures, but will directly control the engine to start according to the conventional starting strategy. That is, the starter motor or a motor drives the engine to the starting speed, the injectors inject fuel according to the injection pulse width calibrated at room temperature, and the spark plugs ignite at the preset time, allowing the engine to enter a self-running state. This is the fourth branch.

[0075] Through the differentiated control of the above four branches, the embodiments of this application can adaptively select the most suitable start-up or preheating strategy according to different combinations of engine temperature and battery charge as soon as the vehicle is powered on. This enables the engine to start or enter pure electric standby mode in the optimal way under different low temperature and different charge conditions, which not only ensures start-up reliability but also optimizes the energy utilization efficiency of the whole vehicle.

[0076] The process of the first method has been explained above; now, we will continue with the explanation of the second method.

[0077] A control method for a hybrid electric vehicle, applied to a hybrid electric vehicle including an engine, a throttle valve 6, an intake manifold 8, and a heating system, wherein the engine is an intake manifold fuel injection engine, and the specific structure can be found in [reference needed]. Figure 1 As shown. The method includes steps S41-S43, which can be found in detail in the reference. Figure 4 As shown: Step S41: Obtain the temperature of the intake manifold 8 and the battery charge of the hybrid vehicle; Step S42: If the temperature of the intake manifold 8 is less than or equal to the first preset temperature and the battery charge is greater than or equal to the first charge threshold and less than or equal to the second charge threshold, then the throttle valve 6 is opened and the heating system is controlled to output warm air to the intake manifold 8 so that the warm air passes through the intake manifold 8 to preheat the intake manifold 8. Step S43: After preheating the intake manifold 8 to a temperature greater than or equal to the second preset temperature, stop the preheating process and control the engine to start, wherein the first preset temperature is less than the second preset temperature.

[0078] Regarding step S41, the temperature of the intake manifold 8 is obtained by a temperature sensor installed inside the intake manifold 8. This temperature sensor collects the gas temperature inside the intake manifold 8 in real time and transmits the detection signal to the controller. The battery charge is calculated by the battery management system after monitoring the voltage, current, temperature, and other state parameters of the power battery in real time, using a state of charge estimation algorithm. The controller communicates with the battery management system through the controller local area network bus to read the battery charge information. Unlike the "engine temperature" obtained in the first method, the second method obtains the "intake manifold 8 temperature." This is because the core preheating target of the second method is the intake manifold 8 itself, so using the temperature of the intake manifold 8 as the basis for preheating start and termination judgments is more direct and accurate.

[0079] Regarding step S42, when the temperature of the intake manifold 8 is less than or equal to the first preset temperature and the battery charge is greater than or equal to the first charge threshold and less than or equal to the second charge threshold, the throttle valve 6 is opened and the heating system is controlled to output warm air to the intake manifold 8, so that the warm air passes through the intake manifold 8 to preheat it. It should be noted that the purpose of keeping the throttle valve 6 open in this step is to provide a complete flow path for the warm air. Specifically, the warm air generated by the heating system enters the intake manifold 8 through preheating pipes 20 and 21. If the throttle valve 6 is closed, the warm air accumulates inside the intake manifold 8 and cannot continue to flow forward, thus limiting heat exchange efficiency. When the throttle valve 6 is open, the warm air passes through the intake manifold 8 and can dissipate outward through the throttle valve 6 and the intake pipe upstream of the throttle valve 6, forming a continuous airflow channel from the heating system, preheating pipes 20 and 21, intake manifold 8, throttle valve 6, and intake pipe. During this flow, the warm air continuously exchanges heat with the wall of the intake manifold 8, thereby achieving continuous heating of the intake manifold 8. In this process, because the throttle valve 6 is open, the internal air pressure of the intake manifold 8 remains connected to the outside atmosphere. The warm air is not forcibly drawn into the combustion chamber, but mainly flows through the cavity of the intake manifold 8 and releases heat on the manifold wall.

[0080] In the second method, there is no limitation on whether the electric motor reverse-drives the engine. The power for delivering warm air is provided by the heater system's own fan, without the need for the suction effect generated by the movement of piston 15. Furthermore, after the second method is completed, if it is determined that the overall engine temperature has not yet reached the thermal state required for starting (for example, the combustion chamber wall temperature is still low), the first method can be continued based on the second method. That is, by closing the throttle valve 6 and controlling the electric motor to reverse-drive the engine, warm air is further introduced into the combustion chamber to supplement the heating of the combustion chamber wall and the top of piston 15. This allows the two methods to form a progressive and complementary relationship, which can be flexibly switched according to the actual preheating needs.

[0081] Regarding step S43, after preheating to a temperature greater than or equal to the second preset temperature in the intake manifold 8, the preheating process is stopped, and the engine is started. The first preset temperature is less than the second preset temperature. During the preheating process, the temperature sensor continuously monitors the temperature of the intake manifold 8 and transmits the monitoring results to the controller in real time. The controller compares the current temperature of the intake manifold 8 with the pre-stored second preset temperature. When the controller determines that the current temperature of the intake manifold 8 is greater than or equal to the second preset temperature, it indicates that the wall of the intake manifold 8 has been preheated to a temperature level sufficient to provide good atomization for the injected fuel. At this time, the controller issues a command to close the heater valves 9 and 22 to cut off the heater supply path and determines whether to shut down the heater system based on actual needs. Simultaneously, since the throttle valve 6 is open during the preheating process, when preheating is stopped, the throttle valve 6 needs to be adjusted to a suitable opening position for engine starting, or, if it is decided to continue executing the first method, the throttle valve 6 can be kept closed and the motor can be started for reverse drag. The controller then controls the starter motor or the motor to drive the engine to the starting speed, and controls the injectors to inject fuel and the spark plugs to ignite, so that the engine enters the self-running state. The second preset temperature in this termination condition is also taken in the range of 0℃ to 10℃ (excluding 0℃), and its setting is consistent with the consideration of the corresponding temperature threshold in the first method.

[0082] Based on the aforementioned operations of obtaining the intake manifold 8 temperature and battery charge, opening the throttle valve 6 and outputting warm air to preheat the intake manifold 8 when conditions are met, and stopping preheating and starting the engine after the temperature reaches the target, this control process provides a low-energy preheating scheme for the low-temperature start characteristics of intake manifold fuel injection engines. Because the opening of the throttle valve 6 forms a continuous airflow channel from the preheating pipes 20 and 21 through the intake manifold 8 to the throttle valve 6, the warm air can continuously exchange heat with the manifold wall as it flows through the intake manifold 8, efficiently transferring heat to the intake manifold wall and the area behind the intake valve 11. These areas are crucial locations where fuel directly contacts and condenses after being injected into the intake manifold fuel injection engine under low-temperature conditions. By preheating these areas, the injected fuel achieves a higher evaporation temperature upon contact with the wall, thus significantly improving its atomization state before entering the cylinder.

[0083] Compared to the first method, the second method eliminates the need for a motor to reverse-drive the engine to establish negative pressure and for introducing warm air into the combustion chamber, thus significantly reducing energy consumption and mechanical losses. Furthermore, if the overall engine temperature still hasn't reached optimal starting conditions after the second method is executed, the first method can be continued to further introduce warm air into the combustion chamber for supplementary heating. This allows for a flexible combination of the two preheating methods based on actual temperature requirements without increasing additional hardware costs. The various operations work in tandem, firstly using the intake manifold 8 temperature as a criterion, then using the opening of the throttle valve 6 to create a continuous airflow channel for warm air delivery, and finally exiting when the target temperature is reached. This ensures that the entire preheating process revolves around the core objective of "improving the intake manifold wall temperature." This control flow, along with the aforementioned first method, forms a flexible relationship that allows for both independent use and progressive coordination, further enhancing the adaptability and energy management flexibility of this embodiment under different low-temperature and power conditions.

[0084] Based on the same inventive concept, this application provides a control system for a hybrid electric vehicle, including a controller, an engine, an intake manifold 8, a motor, and a heating system. The controller is used to execute the aforementioned first hybrid electric vehicle control method, and the heating system outputs warm air to preheat the intake manifold 8 and the engine.

[0085] The controller communicates with the engine, motor, and heating system via signal lines or a controller area network bus, sending control commands to each component and receiving status signals from them. The engine and motor are mechanically connected, specifically, the motor rotor is driven by the engine crankshaft 16, allowing the motor to drive the crankshaft 16 to rotate and reverse-drive the engine, or to drive the motor to generate electricity when the engine is running. The outlet of the intake manifold 8 is connected to the intake passage of the engine cylinder head 12, and the intake port of the intake manifold 8 is connected to the upstream intake pipe via the throttle valve 6. Fresh air from the air filter 1 passes sequentially through the intake pipe 2, turbocharger 3, intercooler 5, and throttle valve 6 before entering the intake manifold 8, and is then distributed to the engine cylinders by the intake manifold 8. The heater core of the heating system connects to the intake manifold 8 via preheating pipes 20 and 21, which are equipped with heater valves 9 and 22, or to the intake pipe between the throttle valve 6 and the intercooler 5 via preheating pipes 20 and 21. The warm air generated by the heating system is delivered to the intake manifold 8 or the intake pipe via the preheating pipes 20 and 21 and the heater valves 9 and 22. A temperature sensor is located on the intake manifold 8 or in the engine combustion chamber to detect the temperature of the intake manifold 8 or the engine temperature and transmits the detection signal to the controller. The battery management system communicates with both the power battery and the controller to monitor the battery level and send the level information to the controller via the controller's local area network bus.

[0086] The controller is used to execute the aforementioned control method for the first type of hybrid electric vehicle, and it forms a closed-loop control with each actuator through signal interaction. Specifically, the controller first obtains the engine temperature or the intake manifold 8 temperature through a temperature sensor, and obtains the battery charge through the battery management system, using these as decision inputs. When it is determined that the engine temperature is less than or equal to a first preset temperature and the battery charge is between a first charge threshold and a second charge threshold, the controller sends a start command to the heating system to generate warm air, and at the same time sends an opening command to the heating valves 9 and 22 to deliver warm air to the intake manifold 8 through the preheating pipes 20 and 21; the controller also sends a reverse drag command to the motor to drive the engine crankshaft 16 to rotate, driving the piston 15 to reciprocate within the cylinder. When the motor is in reverse drag and the throttle valve 6 is closed, the reciprocating motion of the piston 15 creates a periodic negative pressure inside the intake manifold 8. This negative pressure draws warm air from the intake manifold 8 through the intake valve 11 into the combustion chamber. As the warm air flows through the intake manifold 8 and the combustion chamber, it exchanges heat with the intake manifold walls, the back of the intake valve 11, the top of the piston 15, and the cylinder walls, thus preheating these areas. During preheating, the temperature sensor continuously monitors the temperature and feeds the results back to the controller, which compares the current temperature with a second preset temperature. When the temperature reaches the second preset temperature, the controller sends a closing command to the heater valves 9 and 22 to cut off the heater path and sends a stop reverse drag command to the motor to bring the engine back to a standstill, subsequently controlling the engine to start. Furthermore, if the battery charge drops below a first charge threshold during preheating, the controller can prematurely terminate preheating and switch to a starting mode that increases fuel injection. Through the unified coordination of the controller, the above-mentioned structures form a complete interaction relationship at two levels: signal flow (temperature signal, electrical signal, control command) and energy flow (electrical energy drives the motor, and thermal energy is transferred to the engine via the heater). Together, they achieve the preheating treatment of the intake manifold 8 and the engine in low-temperature environments, thereby improving the engine's low-temperature start-up performance.

[0087] Based on the same inventive concept, this application provides a control system for a hybrid electric vehicle, including a controller, an engine, a throttle valve 6, an intake manifold 8, and a heating system. The controller is used to execute the aforementioned second hybrid electric vehicle control method, and the heating system outputs warm air to preheat the intake manifold 8.

[0088] The controller is connected to the engine, throttle valve 6, and heating system via signal lines or a controller area network bus to send control commands to each component and receive status signals from each component. The throttle valve 6 is located upstream of the intake manifold 8, and its outlet is connected to the intake port of the intake manifold 8. Fresh air from the air filter 1 passes sequentially through the intake pipe 2, turbocharger 3, and intercooler 5 before reaching the throttle valve 6. After the flow rate is regulated by the throttle valve 6, it enters the intake manifold 8 and is then distributed to the cylinders of the engine. The outlet of the intake manifold 8 is connected to the intake passage of the engine cylinder head 12, and the engine's intake passage is connected to the combustion chamber via the intake valve 11. The heater outlet of the heating system is connected to the intake manifold 8 via preheating pipes 20 and 21, which are equipped with heater valves 9 and 22. The warm air generated by the heating system is delivered to the intake manifold 8 via the preheating pipes 20 and 21 and the heater valves 9 and 22. A temperature sensor is installed on the intake manifold 8 to detect the temperature inside the intake manifold 8 and transmit the detection signal to the controller. The battery management system is communicatively connected to both the power battery and the controller to monitor the battery level and send the level information to the controller via the controller's local area network bus.

[0089] The controller is used to execute the aforementioned second hybrid vehicle control method, forming a closed-loop control with each actuator through signal interaction. Specifically, the controller first obtains the temperature of the intake manifold 8 through a temperature sensor installed on the intake manifold 8, and obtains the battery charge through the battery management system, using these as decision inputs. When it is determined that the temperature of the intake manifold 8 is less than or equal to a first preset temperature and the battery charge is between a first charge threshold and a second charge threshold, the controller sends an opening command to the throttle valve 6, switching the throttle valve 6 from the closed state to the open state; at the same time, it sends a start command to the heating system, causing the heating system to generate warm air, and sends an opening command to the heating valves 9 and 22, so that the warm air is delivered to the intake manifold 8 through the preheating pipes 20 and 21. The purpose of opening the throttle valve 6 is to provide a complete flow path for the warm air. After entering the intake manifold 8, the warm air can dissipate outward through the open throttle valve 6 and its upstream intake pipe, forming a continuous airflow channel from the heating system through preheating pipes 20 and 21, the intake manifold 8, the throttle valve 6, and back to the intake pipe. During the flow of the warm air through the intake manifold 8, it continuously exchanges heat with the inner wall of the manifold, releasing heat onto the wall surface of the intake manifold 8, thus preheating the intake manifold 8. During this process, the heating system's own fan provides the driving force for the warm air delivery; the motor does not need to reverse-drive the engine, and the engine remains stationary. During preheating, the temperature sensor continuously monitors the temperature of the intake manifold 8 and feeds the results back to the controller. The controller compares the current temperature with a second preset temperature. When the temperature of the intake manifold 8 reaches the second preset temperature, the controller sends a closing command to the heating valves 9 and 22 to cut off the warm air passage and sends an adjustment command to the throttle valve 6, adjusting it to a suitable opening position for engine starting, and then controls the engine to start. Furthermore, after the second method is completed, if it is determined that the overall engine temperature has not yet reached the optimal starting condition, the controller can continue to execute the first method based on the second method. That is, close the throttle valve 6 and control the electric motor to reverse-drive the engine, further introducing warm air into the combustion chamber for supplementary heating. The two methods can be used in a progressive manner according to actual needs. Through the unified coordination of the controller, the above-mentioned structures form a complete interaction relationship at two levels: signal flow (temperature signal, electrical signal, control command) and airflow channel (the complete flow path of warm air through preheating pipes 20, 21, intake manifold 8, throttle valve 6 to the intake pipe). Together, they achieve preheating treatment of intake manifold 8 in low-temperature environments, thereby improving the low-temperature starting performance of the intake manifold fuel injection engine.

[0090] Based on the same inventive concept, embodiments of this application provide a hybrid electric vehicle, including any of the hybrid electric vehicle control systems described above.

[0091] Since the electronic device described in this embodiment is an electronic device used to implement the information processing method in the embodiments of this application, those skilled in the art can understand the specific implementation methods and various variations of the electronic device in this embodiment based on the information processing method described in the embodiments of this application. Therefore, how the electronic device implements the method in the embodiments of this application will not be described in detail here. Any electronic device used by those skilled in the art to implement the information processing method in the embodiments of this application falls within the scope of protection of this application.

[0092] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0096] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0097] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A control method for a hybrid electric vehicle, characterized in that, Applied to a hybrid electric vehicle, the hybrid electric vehicle including an engine, an intake manifold, an electric motor, and a heating system, the method includes: The temperature of the engine and the battery charge of the hybrid vehicle are obtained. When the engine temperature is less than or equal to a first preset temperature, and the battery charge is greater than or equal to a first charge threshold and less than or equal to a second charge threshold, the heating system is controlled to output warm air to the intake manifold and the motor is controlled to reverse-drive the engine so that the warm air enters the engine through the intake manifold to preheat the intake manifold and the engine. After the engine is preheated to a temperature greater than or equal to a second preset temperature, the preheating process is stopped, and the engine is started, wherein the first preset temperature is less than the second preset temperature.

2. The control method for a hybrid electric vehicle as described in claim 1, characterized in that, The warm air outlet of the heating system is connected to the intake manifold via a preheating pipe equipped with a warm air valve. Controlling the heating system to output warm air to the intake manifold includes: The heating system is activated to generate warm air, and the heating valve is opened so that the heating system outputs warm air to the intake manifold.

3. The control method for a hybrid electric vehicle as described in claim 1, characterized in that, The hybrid vehicle also includes a throttle valve, which is closed during the process of controlling the electric motor to reverse-drag the engine.

4. The control method for a hybrid electric vehicle as described in claim 1, characterized in that, After obtaining the engine temperature and the battery charge of the hybrid vehicle, the method further includes: If the engine temperature is less than or equal to the first preset temperature and the battery charge is less than the first charge threshold, then the engine injectors are controlled to increase the fuel injection quantity and start the engine.

5. The control method for a hybrid electric vehicle as described in claim 4, characterized in that, Controlling the engine's injectors to increase fuel injection and start the engine includes: Before starting the engine, control the engine's injectors to inject fuel N times, and then control the engine to start, where N is a positive integer less than 4; or, Control the engine to start and extend the fuel injection duration of the injector.

6. The control method for a hybrid electric vehicle as described in claim 1, characterized in that, The first preset temperature is greater than the engine's minimum operating temperature and less than or equal to -10°C, and the second preset temperature is greater than 0°C and less than or equal to 10°C.

7. The control method for a hybrid electric vehicle as described in claim 1, characterized in that, The first power threshold is greater than or equal to 14%, and the power span between the first power threshold and the second power threshold is negatively correlated with the battery capacity of the power battery of the hybrid vehicle.

8. The control method for a hybrid electric vehicle as described in claim 7, characterized in that, The second power threshold is 17%-25%.

9. A control method for a hybrid electric vehicle as described in any one of claims 1-8, characterized in that, The heating system includes a heating element, which includes a heating core and / or an electric heater.

10. A control method for a hybrid electric vehicle as described in any one of claims 1-8, characterized in that, The engine is either a port fuel injection engine or a direct injection engine.

11. A control method for a hybrid electric vehicle as described in any one of claims 1-8, characterized in that, The temperature of the engine is the temperature of the engine's combustion chamber or the temperature of the intake manifold.

12. A control method for a hybrid electric vehicle, characterized in that, Applied to a hybrid electric vehicle, the hybrid electric vehicle including an engine, a throttle body, an intake manifold, and a heating system, the method includes: The temperature of the intake manifold and the battery charge of the hybrid vehicle are obtained. If the temperature of the intake manifold is less than or equal to the first preset temperature and the battery charge is greater than or equal to the first charge threshold and less than or equal to the second charge threshold, then the throttle valve is opened and the heating system is controlled to output warm air to the intake manifold so that the warm air passes through the intake manifold to preheat the intake manifold. After preheating the intake manifold to a temperature greater than or equal to a second preset temperature, the preheating process is stopped, and the engine is started, wherein the first preset temperature is less than the second preset temperature.

13. The control method for a hybrid electric vehicle as described in claim 12, characterized in that, The engine is a port fuel injection engine.

14. A control system for a hybrid electric vehicle, characterized in that, The device includes a controller, an engine, an intake manifold, a motor, and a heating system. The controller is used to execute a control method for a hybrid electric vehicle according to any one of claims 1-11, and the heating system outputs warm air to preheat the intake manifold and the engine.

15. A control system for a hybrid electric vehicle, characterized in that, The device includes a controller, an engine, a throttle body, an intake manifold, and a heating system. The controller is used to execute a control method for a hybrid electric vehicle according to any one of claims 12-13, and the heating system outputs warm air to preheat the intake manifold.

16. A hybrid electric vehicle, characterized in that, Including a control system for a hybrid electric vehicle as described in claim 14 or 15.

Images