Method and apparatus for controlling engine starting of hybrid vehicle

Abstract

The invention provides a method for controlling start of an engine of a hybrid vehicle, which comprises the following steps: detecting a cold start working condition of the engine in response to an engine start request of the hybrid vehicle; when a cold start condition of the engine is detected, heat generated by an electric driving component of the hybrid vehicle is at least partially transferred to the engine to preheat the engine, and the electric driving component is used for providing power for the hybrid vehicle through electric power. Before heat generated by an electric drive component of the hybrid vehicle is at least partially transferred to the engine, the electric drive component is placed in a predetermined operating state, and the temperature of the electric drive component is continuously monitored during warm-up of the engine. Based on the temperature of the electric driving component, the electric driving component is controlled to temporarily exit the preset operation state and enter the preset operation state again; the engine is controlled to start when the engine is warmed up such that an engine start condition is reached.

Description

Technical Field

[0001] The present invention relates to a method for controlling the start of an engine of a hybrid vehicle. The present invention also relates to a device for controlling the start of an engine of a hybrid vehicle, a cooling system for a hybrid vehicle and a machine-readable storage medium. Background Art

[0002] In recent years, as energy and environmental issues have become increasingly tense, hybrid vehicles using engines and motors as power sources have developed rapidly. However, there are also certain problems. In cold environments, the lubrication conditions in the engine are poor. When the engine is started in this situation, it will not only cause great damage to the engine performance and service life, but also increase emissions.

[0003] In traditional designs, glow plugs are used as cold start assist devices to increase the temperature of the air in the cylinder by releasing heat when the engine is started, thereby improving the engine's low-temperature starting performance. However, this solution requires modification of the engine body, and the overall design is complex, the cost is high, and the scope of application is limited.

[0004] In this context, it is desirable to provide an engine cold start solution for a hybrid vehicle to more effectively control engine warm-up. Summary of the invention

[0005] The object of the present invention is to provide a method for controlling the start of an engine of a hybrid vehicle, the method comprising the following steps:

[0006] In response to an engine start request of the hybrid vehicle, detecting a cold start condition of the engine;

[0007] Upon detecting a cold start condition of the engine, at least partially transferring heat generated by an electric drive component of a hybrid vehicle to the engine to preheat the engine, wherein the electric drive component is used to power the hybrid vehicle by electricity, wherein before at least partially transferring the heat generated by the electric drive component of the hybrid vehicle to the engine, the electric drive component is placed in a predetermined operating state, the temperature of the electric drive component is continuously monitored during preheating the engine, and the electric drive component is controlled to temporarily exit the predetermined operating state and re-enter the predetermined operating state based on the temperature of the electric drive component; and

[0008] When the engine is preheated so that the engine start condition is met, the engine is controlled to start.

[0009] The present invention particularly includes the following technical concepts: by utilizing the heat generated by the electric drive components to preheat the engine, an additional auxiliary preheating device is omitted, and the cost and system complexity are reduced. While ensuring that the engine of the hybrid vehicle is fully preheated, the heat generated by the electric drive components will not be lost in the form of thermal energy, thereby improving energy utilization and allowing the engine to heat up faster. In addition, by dynamically controlling the suspension and continuation of the preheating process according to the heating conditions of the electric drive components, it is possible to effectively prevent the electric drive components from staying in a predetermined operating state for a long time and causing overheating and damage.

[0010] Optionally, the heat generated by the electric drive components of the hybrid vehicle is at least partially transferred to the engine by controlling the electric drive component cooling circuit to communicate with the engine cooling circuit so that the coolant heated by the electric drive component can be directed to the engine. Thus, the coolant heated by the electric drive component can be provided to the engine for preheating, so that the engine can operate normally under low temperature conditions and be heated more evenly.

[0011] Optionally, during the period when the electric drive component cooling circuit is connected to the engine cooling circuit, the cooling mechanism of the electric drive component is controlled to stop working and / or the coolant circulation of the electric drive component cooling circuit is controlled not to pass through the cooling mechanism of the electric drive component, and the cooling mechanism is used to cool the coolant heated by the electric drive component. Thus, even if the cooling mechanism of the electric drive component is turned off, the low-temperature engine can still be used to cool the coolant, thereby reducing the energy consumption of the cooling mechanism.

[0012] Optionally, the electric drive component cooling circuit is switched from the first cooling cycle to the second cooling cycle by controlling the switching mechanism. In the first cooling cycle, the electric drive component cooling circuit is separated from the engine cooling circuit, and in the second cooling cycle, the electric drive component cooling circuit is connected to the engine cooling circuit. By dynamically switching the circulation state of the electric drive component cooling circuit, the connection relationship between the two cooling circuits can be flexibly controlled, not only can the electric drive component coolant be used to heat the engine at low temperatures, but also the two cooling circuits can be made not to interfere with each other under normal circumstances.

[0013] Optionally, the electric drive component of the hybrid vehicle includes at least one of the following: a drive motor; a generator; and / or an inverter. Thus, the energy generated by the electric drive component in the form of thermal energy can be more fully utilized, which is both environmentally friendly and energy-saving.

[0014] Optionally, when the electric drive component involves a drive motor, the predetermined operating state at least includes a stalled state of the drive motor. Thus, in the stalled state, the drive motor can generate more heat than in a normal torque state, so the preheating method is more efficient and the engine heats up faster.

[0015] Optionally, the method further comprises the following steps: checking whether the preheating completion condition is met based on the temperature of the engine; and when the preheating completion condition is met, stopping the preheating of the engine by means of the heat generated by the electric drive component of the hybrid vehicle by: terminating the predetermined operating state of the electric drive component, and / or controlling the electric drive component cooling circuit and the engine cooling circuit to be connected to each other and separated. Thus, the preheating duration can be effectively controlled according to the engine temperature, and while ensuring that the engine of the hybrid vehicle is fully preheated, the normal operation of the electric drive component and its cooling process are not affected.

[0016] Optionally, the engine start condition is determined to be met when the engine temperature is higher than a first predetermined temperature, and the preheating completion condition is determined to be met when the engine temperature is higher than a second predetermined temperature, and the first predetermined temperature is lower than the second predetermined temperature. Thus, by continuing to maintain the preheating process after the engine is started, the catalyst in the exhaust pipe can continue to quickly heat up to the ignition temperature, and the pollutants can be fully catalytically converted when passing through the catalyst, thereby reducing pollutant emissions.

[0017] Optionally, the method further comprises the following steps: checking whether the hybrid vehicle meets the safety preheating condition; and allowing the engine to be preheated by means of the heat generated by the electric drive component only if it is determined that the hybrid vehicle meets the safety preheating condition, wherein the safety preheating condition comprises: the handbrake of the hybrid vehicle is pulled up and / or the hybrid vehicle is in neutral. Thus, the vehicle is prevented from moving suddenly by operating the electric drive component when the vehicle is parked, thereby improving the safety of the preheating solution.

[0018] According to a second aspect of the present invention, there is provided a device for controlling the start of an engine of a hybrid vehicle, the device being used to execute the method according to the first aspect of the present invention, the device comprising:

[0019] a checking module configured to detect a cold start condition of the engine in response to an engine start request of the hybrid vehicle;

[0020] a preheating module configured to transfer at least part of the heat generated by the electric drive component of the hybrid vehicle to the engine to preheat the engine when a cold start condition of the engine is detected, the electric drive component being used to power the hybrid vehicle by electricity, the preheating module further configured to place the electric drive component in a predetermined operating state before at least part of the heat generated by the electric drive component of the hybrid vehicle is transferred to the engine, continuously monitor the temperature of the electric drive component during preheating of the engine, and control the electric drive component to temporarily exit the predetermined operating state and re-enter the predetermined operating state based on the temperature of the electric drive component; and

[0021] The starting module is configured to control the engine to start when the engine is preheated to meet the engine starting condition.

[0022] According to a third aspect of the present invention, there is provided a cooling system for a hybrid vehicle, the cooling system comprising:

[0023] The device according to the second aspect of the present invention

[0024] engine cooling circuit; and

[0025] An electric drive component cooling circuit comprises a switching mechanism, wherein the switching mechanism is configured to enable the electric drive component cooling circuit to switch between a first cooling cycle and a second cooling cycle under the control of the device, wherein the electric drive component cooling circuit is separated from the engine cooling circuit in the first cooling cycle and the electric drive component cooling circuit is connected to the engine cooling circuit in the second cooling cycle so that the coolant heated by the electric drive component can be guided to the engine.

[0026] According to a fourth aspect of the present invention, there is provided a machine-readable storage medium, on which a computer program is stored, wherein the computer program is used to execute the method according to the first aspect of the present invention when executed on a computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood. The accompanying drawings include:

[0028] Figure 1a and Figure 1b A schematic diagram showing a powertrain system of a hybrid vehicle according to an exemplary embodiment of the present invention is shown;

[0029] Figure 2 A flow chart showing a method for controlling engine start of a hybrid vehicle according to an exemplary embodiment of the present invention;

[0030] Figure 3 Shows Figure 2 A flow chart of one method step of the method shown;

[0031] Figure 4 A flow chart showing a method for controlling engine start of a hybrid vehicle according to another exemplary embodiment of the present invention;

[0032] Figure 5a and Figure 5b A schematic diagram showing a cooling system for a hybrid vehicle according to an exemplary embodiment of the present invention is shown;

[0033] Figure 6aand Figure 6b A schematic diagram showing a cooling system for a hybrid vehicle according to another exemplary embodiment of the present invention; and

[0034] Figure 7 The graph shows the time curves of the drive motor operating mode, the engine water outlet temperature and the engine speed when the engine is started by means of the method according to the present invention. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the scope of protection of the present invention.

[0036] Figure 1a and Figure 1b A schematic diagram of a powertrain system of a hybrid vehicle according to an exemplary embodiment of the present invention is shown.

[0037] exist Figure 1a A series hybrid vehicle is shown in FIG. , which is also commonly referred to as an extended-range electric vehicle. Figure 1a As shown, the powertrain system of a series hybrid electric vehicle includes an engine 1, a generator 2, an inverter 3, a power battery 4 and a drive motor 5 connected in sequence. The inverter 3 is used to convert power between the power battery 4 and the generator 2 and the drive motor 5. In this type of hybrid vehicle, the engine 1 drives the generator 2 to generate electricity, and its electric energy is directly transmitted to the drive motor 5 through the inverter 3, and the drive motor 5 generates torque to drive the vehicle. Alternatively, the electric energy provided by the generator 2 can also be stored in the power battery 4 through the inverter 3, and the drive motor 5 uses the power provided by the power battery 4 to operate. In this embodiment, the drive motor 5, the generator 2 and the inverter 3 are also defined as the electric drive components of the hybrid vehicle, which are used to provide power to the hybrid vehicle through electricity.

[0038] exist Figure 1b A parallel hybrid vehicle is shown in FIG. The powertrain system of the parallel hybrid vehicle includes an engine 1, a drive motor 5, a power battery 4, and a transmission mechanism 6. In this type of hybrid vehicle, the drive motor 5 is defined as the electric drive component of the vehicle. Through the transmission mechanism 6, the engine 1 can be coupled to the drive motor 5, so that the vehicle can be driven by the engine 1 and the drive motor 5 together or separately. When the power battery 4 is low on power, the engine 1 can also drive the drive motor 5 to reverse to charge the battery 4.

[0039] In addition, Figure 1a and Figure 1bAlso shown in the figure are devices 10 for controlling the start of the engine of a hybrid vehicle, which are connected to the engine 1 and various electric drive components through the in-vehicle network to monitor and control their operating states. Specifically, the device 10 includes a check module 11, a preheating module 12 and a start module 13, and these modules 11, 12, 13 are connected to each other in communication technology. The check module 11 is used to receive a start request of the engine 1 of the hybrid vehicle, and detect the cold start condition of the engine 1 when receiving such a request. When the preheating module 12 detects the cold start condition of the engine 1, the heat generated by the electric drive component of the hybrid vehicle is at least partially transferred to the engine 1 to preheat the engine. As described above, the electric drive component refers to a component that provides power to the hybrid vehicle through electricity, which includes, for example, a drive motor 5, an inverter 3 and / or a generator 1. In addition, the preheating module 12 is also configured to be able to control the operating state of the drive motor 5 and monitor its temperature in real time. Specifically, before at least partially transferring the heat generated by the electric drive components 2, 3, 5 of the hybrid vehicle to the engine 1, the preheating module 12 may place the electric drive components 2, 3, 5 in a predetermined operating state, and during the preheating period, control them to temporarily exit the predetermined operating state and re-enter the predetermined operating state based on the temperature of the electric drive components 2, 3, 5. The starting module 13 stores the starting condition of the engine 1, which can be defined, for example, by the temperature of the engine 1. The starting module 13 is used to control the engine 1 to start when the engine 1 is preheated to meet the engine starting condition.

[0040] Figure 2 A flow chart of a method for controlling engine start of a hybrid vehicle according to an exemplary embodiment of the present invention is shown. Figure 1a and Figure 1b The device 10 shown is implemented in the context of.

[0041] In step S0 , it is checked whether an engine start request of a hybrid vehicle is received.

[0042] In some cases, hybrid vehicles are not driven purely electrically, but require support from the engine. For example, if a larger starting power is required when the vehicle starts or if a higher torque is required during vehicle driving, the pure electric mode cannot provide the starting power or the required torque, so the engine needs to be started. For another example, if the battery is low, the engine will also be needed to power the motor or charge the battery, and there is also an engine start request. For another example, if the vehicle is parked for too long, or the brakes were applied too hard in the previous driving cycle, and the pressure in the pressure storage tank is too low, a mechanical air pump needs to be driven to charge the pressure storage tank. At this time, the engine needs to be started to drive the mechanical air pump, so there is also an engine start request.

[0043] If no engine start request is received, the process continues in step S0 . If an engine start request is received, a cold start condition of the engine is detected in the next step S1 .

[0044] In the sense of the present invention, the "cold start condition" of the engine means that the engine needs to be started when the water temperature is low, which generally occurs when the vehicle is stationary for a long time in winter or when it has been a long time since it was last started. In one embodiment, the cold start condition can be detected when the temperature of the engine is lower than the expected operating temperature (e.g., -5°C). For example, a temperature sensor can be arranged in the engine cooling circuit, and the temperature of the engine can be characterized by the temperature of the engine water outlet. In addition, the judgment of the cold start condition can also be performed based on the temperature relationship at the engine water outlet and the water inlet.

[0045] If the cold start condition of the engine is detected in step S1, then in step S2, the heat generated by the electric drive components of the hybrid vehicle is at least partially transferred to the engine to preheat the engine. During the preheating of the engine, attention should also be paid to the heating condition of the electric drive components and their operating state should be controlled accordingly. This will be combined with Figure 3 The illustrated embodiment is explained in detail.

[0046] If a cold start condition is not detected in step S1 , the engine is started directly in step S32 .

[0047] In this context, electric drive components refer to components in a hybrid vehicle that use electricity to power the hybrid vehicle, including, for example, drive motors, generators, and inverters. The engine can be preheated by one or more electric drive components, and the number of electric drive components involved in the engine preheating process can be adjusted according to the vehicle operating status and actual preheating requirements.

[0048] In one embodiment, a heat transfer path from the electric drive component to the engine may be formed by controlling the engine cooling circuit and the electric drive component cooling circuit, which will be further described below.

[0049] In step S31, it is checked whether the engine start condition is met.

[0050] In one embodiment, when the temperature of the engine is higher than a first predetermined temperature (e.g., 10°C), it is determined that the heat generated by the electric drive component is sufficient, and therefore the engine start condition is considered to be met. In another embodiment, when the preheating time is greater than a preset time threshold, the engine start condition is considered to be met. Here, both the first predetermined temperature and the preset time threshold can be determined in advance through a pre-calibration process, and can be adjusted in actual use in combination with factors such as engine wear and combustion efficiency.

[0051] If it is determined in step S31 that the engine start condition has not been met, the engine is not started, and the check is continued in step S31. If it is determined that the engine is preheated so that the engine start condition is met, the engine is controlled to start in the next step S32.

[0052] Figure 3 Shows Figure 2 A flow chart of the method steps of the method shown. In this exemplary embodiment, Figure 2 Step S2 of the illustrated method comprises sub-steps S21 - S28 .

[0053] In step S21, it is checked whether the hybrid vehicle meets the safety preheating conditions. In one embodiment, it can be checked whether the handbrake of the hybrid vehicle is pulled up. Additionally or alternatively, it can also be checked whether the hybrid vehicle is in neutral. The purpose of this is to prevent the vehicle from moving suddenly due to the operation of the electric drive components when the vehicle is stationary. If the safety preheating conditions are not met, the driver can be prompted to pull up the handbrake or put the vehicle in neutral in step S22 through a visual or auditory message in the vehicle. In addition, the handbrake of the hybrid vehicle can also be controlled to be automatically pulled up or the vehicle in the parked state can be automatically put in neutral, and then continue to perform this check in this step.

[0054] Only when the safe preheating conditions are met, the engine preheating with the heat generated by the electric drive component is allowed. Accordingly, in step S23, the electric drive component is placed in a predetermined operating state. In one embodiment, when the electric drive component involves a drive motor, for example, the drive motor can be placed in a stalled state in this step. In the stalled state, although the drive motor is powered on, the speed is zero. In this state, there is a lack of back electromotive force that prevents the stator current from increasing, so the current will increase greatly, causing the drive motor to generate more heat. This ensures that the engine temperature is increased faster at low temperatures. In addition, the predetermined operating state may also include a state in which the drive motor load and speed are appropriately increased or the drive motor coil is temporarily short-circuited. If the electric drive component involves components such as a generator and an inverter, the voltage, current and load can also be adjusted to make their heating conditions in the predetermined operating state higher than when in rated operation.

[0055] In another embodiment, when the electric drive component involves a drive motor, the drive motor may be placed in a normal torque state in step S23. For example, when the vehicle is running in pure electric mode, the motor cannot be immediately heated by stalling, so the drive motor may be kept in a normal torque state and the heat generated by the motor during operation may be effectively used to preheat the engine. In addition, when the drive motor is in a normal torque state, the heat dissipated by other types of electric drive components (such as a generator and an inverter) may be used to preheat the engine.

[0056] Next, in step S24, the electric drive component cooling circuit is controlled to be connected to the engine cooling circuit so that the coolant heated by the electric drive component can be directed to the engine. For example, the electric drive component cooling circuit can be switched from the first cooling cycle to the second cooling cycle by controlling the switching mechanism of the electric drive component. In the first cooling cycle, the electric drive component cooling circuit is separated from the engine cooling circuit, and in the second cooling cycle, the electric drive component cooling circuit is connected to the engine cooling circuit. This will be combined with Figure 5a and Figure 5b as well as Figure 6a and Figure 6b In addition, it is also conceivable that the connection and separation between the engine cooling circuit and the electric drive component cooling circuit can be controlled by changing the circulation mode of the engine cooling circuit.

[0057] It is currently known that the drive motor generates more heat in a stalled state. If the heat cannot be removed in time or if the motor stays in a stalled state for too long, the motor temperature will rise or even burn out. Therefore, it is necessary to adjust the operating state of the drive motor by a thermal management system according to the temperature of the drive motor. For example, the electric drive component can be controlled to temporarily exit and re-enter a predetermined operating state based on the temperature of the electric drive component through the cycle shown in steps S25-S28.

[0058] Specifically, taking the drive motor as an example, in step S25, a temperature sensor can be arranged in the cooling circuit of the electric drive component, and the temperature of the drive motor can be characterized by the temperature of the drive motor outlet, and then the temperature of the drive motor is checked to see if it exceeds a predetermined upper limit. Here, the predetermined upper limit can be related to the insulation level adopted by the drive motor, which is determined according to the design and manufacturing standards of the drive motor, and the motor insulation material should not exceed this temperature to ensure its normal operation. If it exceeds, the drive motor is controlled to exit the stalled state in step S26, and if it does not exceed, the stalled state of the drive motor is maintained. If the drive motor is temporarily exited from the stalled state, the temperature of the drive motor is continuously monitored and checked in step S27 whether its temperature falls back to below a predetermined lower limit. Here, the predetermined lower limit can be defined by deducting a certain margin from the predetermined upper limit. In addition, the predetermined lower limit can also be affected by factors such as ambient temperature, load size, and rotation speed. If this situation is established, the drive motor is placed in a stalled state again in step S28. Then it is circulated between steps S25-S28 accordingly.

[0059] Figure 4 A flow chart of a method for controlling engine start of a hybrid vehicle according to another exemplary embodiment of the present invention is shown. Figure 4 In the embodiment shown, Figure 2The same steps in the method shown have the same reference numerals and will not be described in detail here. Figure 4 and Figure 2 The difference.

[0060] In this embodiment, Figure 2 The method shown also additionally includes steps S41 and S42.

[0061] After the engine is started in step S32, the preheating process is not terminated immediately, but in the next step S41, it is checked whether the preheating completion condition is reached based on the temperature of the engine. For example, the preheating completion condition is determined to be reached when the temperature of the engine is higher than the second predetermined temperature, and the second predetermined temperature mentioned here is preferably higher than the first predetermined temperature mentioned above, for example, 400°C. The second predetermined temperature can be determined, for example, in relation to the conversion efficiency of the catalyst of the hybrid vehicle. It is generally believed that when this temperature is reached, not only the engine is thoroughly lubricated, but also the catalyst can fully function.

[0062] If it is found in step S41 that the preheating completion condition is met, then in step S42, the preheating of the engine by means of the heat generated by the electric drive component of the hybrid vehicle is stopped, otherwise the preheating process is maintained and the check is continued in step S41. Exemplarily, the predetermined operating state of the electric drive component can be terminated in step S42, or the electric drive component cooling circuit and the engine cooling circuit can be controlled to be disconnected from being connected, thereby cutting off the heat transfer path from the electric drive component to the engine.

[0063] Figure 5a and Figure 5b A schematic diagram of a cooling system for a hybrid vehicle according to an exemplary embodiment of the present invention is shown.

[0064] like Figure 5a and Figure 5b As shown, the cooling system 200 is installed in a hybrid vehicle and includes an engine cooling circuit 201, an electric drive component cooling circuit 202, and the device 10 shown in FIG1 . The engine cooling circuit 201 is also called a high-temperature circuit, which is used to guide the coolant to circulate through the engine 1 and its cooling mechanism 21, thereby generating heat exchange and ultimately achieving engine temperature reduction. The electric drive component cooling circuit 202 is also called a medium-temperature circuit, which is used to guide the coolant to circulate through the electric drive component and its cooling mechanism 22 to reduce the heat generated by the electric drive component (here, only the drive motor 5 is shown for simplicity).

[0065] A switching mechanism 25 is provided in the electric drive component cooling circuit 202. The switching mechanism 25 includes, for example, a switch element such as a stop valve. The switching mechanism 25 can change the operating state (for example, on and off) under the control of the device 10 to adjust the circulation state of the electric drive component cooling circuit 202. For example, the switching mechanism 25 can receive Figure 1a and Figure 1b The control signal of the device 10 is shown, so that the electric drive component cooling circuit 202 is selectively switched between the first cooling cycle and the second cooling cycle.

[0066] exist Figure 5a The thick solid line in the figure exemplarily shows the first cooling cycle of the electric drive component cooling circuit 202. In the first cooling cycle, the electric drive component cooling circuit 202 is separated from the engine cooling circuit 201, so that the two cooling circuits work independently without interflow.

[0067] exist Figure 5b The second cooling cycle of the electric drive component cooling circuit 202 is exemplarily shown by a thick solid line. In the case of the second cooling cycle, the water inlet and the water outlet of the electric drive component 5 are respectively connected to the water outlet and the water inlet of the engine 1, thereby connecting the electric drive component cooling circuit 202 with the engine cooling circuit 201. In this way, the coolant heated by the electric drive component 5 is guided to the engine 1 to preheat the engine 1. Optionally, in the case of the second cooling cycle, the connection between the electric drive component 5 and its cooling mechanism 22 can be cut off by the switching mechanism 25, so that the coolant circulation in the electric drive component cooling circuit 202 does not pass through the cooling mechanism 22, or the cooling mechanism 22 of the electric drive component 5 can be controlled to stop working, so as to avoid the loss of heat generated by the electric drive component 5 and reduce the energy consumption of the cooling mechanism 22. Optionally, in the case of the second cooling cycle, the connection between the engine 1 and its cooling mechanism 21 can be cut off or the engine cooling mechanism 21 can be made inoperative, so as to avoid the engine cooling mechanism 21 taking away heat, thereby improving the heating efficiency of the engine 1.

[0068] By changing the working state of the switching mechanism 25, the electric drive component cooling circuit 202 and the engine cooling circuit 201 can be temporarily connected together. In other words, the electric drive component cooling circuit 202 is connected to the engine cooling circuit 201 only when there is a need to preheat the engine 1. If the two circuits 201 and 202 are connected to each other, the coolant flowing out of the electric drive component 5 flows through part of the pipeline of the engine cooling circuit 201, and then flows back to the electric drive component 5 along a predetermined path.

[0069] Figure 6a and Figure 6b A schematic diagram of a cooling system for a hybrid vehicle according to another exemplary embodiment of the present invention is shown.

[0070] In this embodiment, the electric drive component cooling circuit 202 is shown in more detail. Meanwhile, the engine cooling circuit 201 is only partially shown, that is, only part of the pipeline connected to the water inlet and outlet of the engine 1 is shown. Cooling liquid flows through the two cooling circuits 202 and 201 respectively.

[0071] In the engine cooling circuit 201, temperature sensors 51 and 52 are respectively provided at the water inlet and outlet of the engine 1 to monitor the temperature level of the engine 1, thereby identifying the cold start condition. In addition, a temperature sensor may also be provided in the electric drive component cooling circuit 202 (for example, at the water outlet of the drive motor 5) to monitor the heating condition of the electric drive component.

[0072] In the electric drive component cooling circuit 202, the coolant can circulate along two paths. In the first path, the drive motor 5, the first stop valve 54, the cooling mechanism 22, the first coolant pump 56, the inverter 3, the generator 2, and the three-way valve 53 are arranged in sequence. In the second path, the drive motor 5, the second stop valve 55, the second coolant pump 57, the engine 1, and the three-way valve 53 are arranged in sequence. Among them, the water inlet a of the three-way valve 53 is connected to the water outlet of the generator 2, the water inlet b of the three-way valve 53 is connected to the water outlet of the engine 1, and the water outlet c is connected to the water inlet of the drive motor 5. Exemplarily, the cooling mechanism 22 may include a radiator and a fan, which are used to dissipate the heat generated by the electric drive components 2, 3, and 5 into the external environment.

[0073] In this embodiment, Figure 5a and Figure 5b The switching mechanism 25 shown includes a first stop valve 54, a second stop valve 55, a first coolant pump 56, a second coolant pump 57 and a three-way valve 53. By controlling the operating states of these components, the coolant in the electric drive component cooling circuit 202 can selectively flow along any of the two paths mentioned above, so that the entire cooling circuit switches between the first cooling cycle and the second cooling cycle. Specifically, the first coolant pump 56 and the second coolant pump 57 are used to force the coolant to circulate, so as to change the flow direction of the coolant of the electric drive component, so that the engine 1 is heated faster, and a higher thermal energy utilization rate can also be achieved. For example, the first coolant pump 56 can pump the coolant from the water outlet of the drive motor 5 to the cooling mechanism 22 for cooling, and then pump the coolant treated by the temperature reduction to the water inlet of the drive motor 5. The second coolant pump 57 sucks out the coolant from the water outlet of the drive motor 5 and pumps it to the water inlet of the engine 1, so as to heat the engine 1 with the heated coolant.

[0074] For example, the above components included in the switching mechanism 25 can be connected to Figure 1a and Figure 1bThe device 10 shown in the figure is configured to switch the electric drive component cooling circuit 202 between the first cooling cycle and the second cooling cycle in response to the received control command. Figure 6a and Figure 6b 2 and 3. In FIG. 2 , a first cooling cycle and a second cooling cycle of the electric drive component cooling circuit 202 are respectively shown by thick solid lines.

[0075] like Figure 6a As shown, when the temperature sensor 52 arranged at the water outlet of the engine 1 measures that the temperature of the engine 1 is higher than the desired operating temperature (e.g., -5°C), it is determined that there is no preheating demand for the engine 1, so the first coolant pump 56 is controlled to be turned on, the first stop valve 54 is turned on, the second coolant pump 57 is turned off, the second stop valve 55 is turned off, the water inlet a and the water outlet c of the three-way valve 53 are turned on, and the water inlet b is turned off. At this time, the coolant passes through the inverter 3, the generator 2 and the drive motor 5 and is guided to the radiator and the fan 22 for cooling, and then returns to these electric drive components 3, 2, 5 in sequence, thereby completing the first cooling cycle. In this state, the electric drive component cooling circuit 202 is separated from the engine cooling circuit 201, and the coolant heated by the electric drive components 3, 2, 5 is cooled by the radiator and the fan 22.

[0076] like Figure 6b As shown, when the temperature of the engine 1 is measured by the temperature sensor 52 arranged at the water outlet of the engine 1 to be lower than the desired operating temperature (e.g., -5°C), it is determined that the engine 1 is in a cold start condition, which means that the engine 1 has a preheating demand. In this embodiment, the drive motor 5 is placed in a stalled state, and the generator 2 does not work. At the same time, the second coolant pump 57 is controlled to be turned on, the second stop valve 55 is turned on, and the first coolant pump 56 is closed, the first stop valve 54 is turned off, the water inlet b and the water outlet c of the three-way valve 53 are turned on, and the water inlet b is turned off. At this time, the coolant is discharged from the water outlet of the drive motor 5 and then guided to the water inlet of the engine 1, and then discharged from the water outlet of the engine 1 and returned to the drive motor 5, thereby completing the second cooling cycle. In this way, the electric drive component cooling circuit 202 is connected to the engine cooling circuit 201, and the heat generated by the drive motor 5 is guided to the engine 1 through the second cooling cycle to achieve rapid preheating of the engine 1.

[0077] In another embodiment not shown, the drive motor 5 may not be placed in a stalled state, but may be controlled to be in a normal torque state. In this case, the generator 2 and the inverter 3 may also participate in the second cooling cycle, thereby transferring the heat generated by the multiple electric drive components to the engine 1 in the second cooling cycle, accelerating the preheating process.

[0078] In another embodiment not shown, the first path and the second path mentioned above may also constitute a second cooling cycle together. In other words, during the preheating of the engine, the circuit including the fan / radiator is no longer cut off, so that part of the heat generated by the drive motor is dissipated by the cooling mechanism, and only part of the heat is transferred to the engine for the preheating process.

[0079] Figure 7 The graph shows the time curves of the drive motor operating mode, the engine water outlet temperature and the engine speed when the engine is started by means of the method according to the present invention.

[0080] like Figure 7 As shown in the top part, in the initial state, the drive motor is in the normal torque mode M1. At the beginning, the engine water outlet temperature T is low, for example, -5°C, and the engine is determined to be in a cold start condition. In this case, the engine is not started immediately, so the engine speed n is 0rpm at the beginning.

[0081] Before starting the engine, the heat generated by the drive motor is transferred to the engine to preheat the engine. To this end, at time t1, the drive motor is controlled to switch from normal torque mode M1 to stall mode M2. In this embodiment, in order to avoid overheating caused by the drive motor staying in stall mode M2 ​​for too long, the drive motor can be temporarily exited from stall mode M2 ​​according to the temperature of the drive motor, and then re-enter stall mode M2, and so on. For example, when the temperature of the drive motor is higher than a predetermined upper limit value, the drive motor is controlled to temporarily exit the stall mode M2, and when its temperature drops below a predetermined lower limit value, the drive motor is controlled to re-enter the stall mode M2. Here, the specific values ​​of the predetermined upper limit value and the predetermined lower limit value can be set and adjusted according to the heating conditions corresponding to the actual motor model used.

[0082] It can also be seen that as the preheating progresses, the engine water outlet temperature T gradually rises until the engine water outlet temperature T reaches the first predetermined temperature (e.g., 10°C) at time t2, which indicates that the engine start condition has been met. Therefore, at time t2, the engine of the hybrid vehicle is controlled to start, the engine speed n gradually rises from 0rpm and finally reaches 900rpm, and the engine water outlet temperature T further rises as the engine heats up. In addition, in this embodiment, when the engine water outlet temperature T is higher than the first predetermined temperature, the heat generated by it is no longer directed to the engine, and the drive motor is restored from the stall mode M2 ​​to the normal torque mode M1, thereby facilitating the normal driving of the vehicle.

[0083] In another embodiment not shown, after the engine water outlet temperature T reaches the first predetermined temperature, the stall mode M2 ​​of the drive motor is not terminated immediately, but the stall state is maintained and the generated heat is continuously transferred to the engine. When the engine water outlet temperature T is higher than the second predetermined temperature (e.g., 400° C.), it is confirmed that the preheating completion condition is met, and then the drive motor is controlled to exit the stall mode M2, and the heat transfer from the drive motor to the engine is interrupted.

[0084] It should be noted that although the combination Figure 7 Only the case of using the heat generated by the stalled state of the drive motor to preheat the engine is described, but the normal torque state of the drive motor can also be used to preheat the engine. For example, the type of the predetermined operating state of the drive motor can be selected according to the driving state of the hybrid vehicle. Exemplarily, during the hybrid vehicle parking period, the drive motor is controlled to be in the stalled mode, and during the hybrid vehicle driving period, the drive motor is controlled to be in the normal torque mode.

[0085] Additionally or alternatively, the heat generated by other electric drive components (such as a generator and an inverter) and a combination thereof other than the drive motor may also be used to preheat the engine, which all falls within the scope of the present invention.

[0086] It can be understood that the methods of various embodiments of the present disclosure can be implemented by computer programs / software. These software can be loaded into the working memory of the processor and used to execute the methods according to various embodiments of the present disclosure when running.

[0087] According to another embodiment of the present disclosure, a machine-readable storage medium is provided, such as a CD-ROM, which includes a computer program, which, when executed, causes a computer or a processor to perform a method according to each embodiment of the present disclosure. The machine-readable storage medium is, for example, an optical storage medium or a solid-state medium supplied together with other hardware or as part of other hardware.

[0088] Although specific embodiments of the present invention are described in detail herein, they are provided for the purpose of explanation only and should not be considered to limit the scope of the present invention. Various substitutions, changes and modifications may be conceived without departing from the spirit and scope of the present invention.

Claims

1. A method for controlling the start of an engine (1) of a hybrid vehicle, the method comprising the following steps: In response to an engine start request of a hybrid vehicle, detecting a cold start condition of an engine (1); When a cold start condition of an engine (1) is detected, heat generated by an electric drive component (2, 3, 5) of a hybrid vehicle is at least partially transferred to the engine (1) to preheat the engine (1), wherein the electric drive component (2, 3, 5) is used to provide power to the hybrid vehicle by electric power, wherein before the heat generated by the electric drive component (2, 3, 5) of the hybrid vehicle is at least partially transferred to the engine (1), the electric drive component (2, 3, 5) is placed in a predetermined operating state, the temperature of the electric drive component (2, 3, 5) is continuously monitored during the preheating of the engine (1), and the electric drive component (2, 3, 5) is controlled to temporarily exit the predetermined operating state and re-enter the predetermined operating state based on the temperature of the electric drive component (2, 3, 5); as well as When the engine (1) is preheated to meet the engine start condition, the engine (1) is controlled to start.

2. The method according to claim 1, wherein: Heat generated by electric drive components (2, 3, 5) of a hybrid vehicle is at least partially transferred to an engine (1) by: The electric drive component cooling circuit (202) is controlled to communicate with the engine cooling circuit (201) so that the coolant heated by the electric drive component (2, 3, 5) can be guided to the engine (1).

3. The method according to claim 2, wherein: During the period when the electric drive component cooling circuit (202) is connected to the engine cooling circuit (201), the cooling mechanism (22) of the electric drive component (2, 3, 5) is controlled to stop working and / or the coolant circulation of the electric drive component cooling circuit (202) is controlled not to pass through the cooling mechanism (22) of the electric drive component (2, 3, 5), wherein the cooling mechanism (22) is used to cool the coolant heated by the electric drive component (2, 3, 5).

4. The method according to claim 2 or 3, wherein: The electric drive component cooling circuit (202) is switched from a first cooling cycle to a second cooling cycle by controlling a switching mechanism (25); in the case of the first cooling cycle, the electric drive component cooling circuit (202) is separated from the engine cooling circuit (201); in the case of the second cooling cycle, the electric drive component cooling circuit (202) is connected to the engine cooling circuit (201).

5. The method according to any one of claims 1 to 4, wherein: The electric drive component (2, 3, 5) of a hybrid vehicle comprises at least one of the following: Drive motor; Generator; and / or Inverter.

6. The method according to any one of claims 1 to 5, wherein: When the electric drive component (2, 3, 5) is a drive motor, the predetermined operating state at least includes a stalled state of the drive motor.

7. The method according to any one of claims 1 to 6, wherein: The method further comprises the following steps: checking whether a warm-up completion condition is met based on the temperature of the engine (1); and When the preheating completion condition is reached, the preheating of the engine (1) by means of the heat generated by the electric drive components (2, 3, 5) of the hybrid vehicle is stopped in the following manner: a predetermined operating state of the electric drive components (2, 3, 5) is terminated, and / or the electric drive component cooling circuit (202) and the engine cooling circuit (201) are controlled to change from being connected to being separated.

8. The method according to claim 7, wherein: When the temperature of the engine (1) is higher than a first predetermined temperature, it is determined that the engine start condition is met, and when the temperature of the engine (1) is higher than a second predetermined temperature, it is determined that the preheating completion condition is met, and the first predetermined temperature is lower than the second predetermined temperature.

9. The method according to any one of claims 1 to 8, wherein: The method further comprises the following steps: Checking that hybrid vehicles meet safe preheating conditions; and Preheating the engine (1) with the heat generated by the electric drive components (2, 3, 5) is allowed only when it is determined that the hybrid vehicle meets safe preheating conditions, wherein the safe preheating conditions include: the handbrake of the hybrid vehicle is pulled up and / or the hybrid vehicle is in neutral.

10. A device (10) for controlling the start of an engine (1) of a hybrid vehicle, the device (10) being used to execute the method according to any one of claims 1 to 9, the device (10) comprising: A checking module (11) configured to detect a cold start condition of the engine (1) in response to an engine start request of the hybrid vehicle; A preheating module (12) configured to transfer at least part of the heat generated by the electric drive component (2, 3, 5) of the hybrid vehicle to the engine (1) to preheat the engine (1) when a cold start condition of the engine (1) is detected, wherein the electric drive component (2, 3, 5) is used to provide power to the hybrid vehicle through electricity, and the preheating module (12) is also configured to place the electric drive component (2, 3, 5) in a predetermined operating state before at least part of the heat generated by the electric drive component (2, 3, 5) of the hybrid vehicle is transferred to the engine (1), continuously monitor the temperature of the electric drive component (2, 3, 5) during the preheating of the engine (1), and control the electric drive component (2, 3, 5) to temporarily exit the predetermined operating state and re-enter the predetermined operating state based on the temperature of the electric drive component (2, 3, 5); as well as A starting module (13) is configured to control the engine (1) to start when the engine (1) is preheated to meet the engine starting condition.

11. A cooling system (200) for a hybrid vehicle, the cooling system (200) include: The device (10) according to claim 10; an engine cooling circuit (201); and An electric drive component cooling circuit (202) comprises a switching mechanism (25), wherein the switching mechanism (25) is configured to enable the electric drive component cooling circuit (202) to switch between a first cooling cycle and a second cooling cycle under the control of a device (10); in the case of the first cooling cycle, the electric drive component cooling circuit (202) is separated from the engine cooling circuit (201); in the case of the second cooling cycle, the electric drive component cooling circuit (202) is connected to the engine cooling circuit (201), so that the coolant heated by the electric drive component (2, 3, 5) can be guided to the engine (1). 12 . A machine-readable storage medium having a computer program stored thereon, the computer program being configured to execute the method according to claim 1 when executed on a computer.

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