Multi-application scene range extender engine starting control method

Abstract

The invention provides a multi-application scene range extender engine starting control method. The method comprises the steps of range extender engine starting requirement judgment, range extender engine starting control and range extender engine starting result judgment. According to an external driver request and an internal software strategy, high-voltage starting (ISG motor), low-voltage starting (engine starter) or high-low-voltage combined starting is carried out, and the starting requirements of the range extender engine can be met according to different application scenes so as to meet various use scenes of special vehicles.

Description

Technical Field

[0001] The present invention belongs to the technical field, and in particular relates to a method for controlling starting of a range extender engine in multiple application scenarios. Background Art

[0002] In the current context of increasing number of new energy vehicles, the extended-range hybrid architecture is widely used for its advantages of long driving range, low energy consumption and low failure rate. The range extender is the main source of electricity for extended-range vehicles. At present, the range extender engine starting method of mainstream extended-range hybrid vehicles mainly adopts ISG motor (starter generator) to drag the engine to rotate. After the engine detects the speed, it injects fuel and burns, and finally completes the start. Among them, after the vehicle controller (VCU) receives the driver's start command or the start command calculated by the internal software logic, it analyzes the start command through the internal software logic of the VCU, and after judging that the current start conditions are met, it sends the start command to the GCU (ISG motor controller) through the CAN bus; after receiving the start command, the GCU starts to drag the engine to the target speed through internal judgment; the ECU (engine controller) starts to inject fuel through internal strategies after detecting the engine speed signal; when the VCU judges that the engine has started successfully, it sends a 0 torque demand to the GCU, and then the VCU performs other controls on the range extender according to the control strategy. The main starting process is as follows Figure 1 shown.

[0003] Although the entire starting process includes a series of starting condition judgments, this starting control strategy has certain limitations:

[0004] 1. The starting process requires high voltage power supply to the whole vehicle: Under extreme conditions, when the whole vehicle cannot meet the high voltage power supply requirements (such as the high voltage battery SOC is too low), the range extender engine will not be able to start. At this time, the special vehicle will not be able to heat the high voltage battery heating film through the range extender, nor heat the passenger compartment, so it cannot meet the use requirements of special vehicles.

[0005] 2. Under extremely cold temperature conditions, the high-voltage battery cannot be discharged: Under extremely cold temperature conditions, the high-voltage battery of special vehicles cannot be discharged, and the ISG motor cannot output torque to drive the range extender engine to rotate, so it cannot be started. At this time, the special vehicle will not be able to heat the high-voltage battery heating film through the range extender, nor to heat the passenger compartment, so it cannot meet the use needs of special vehicles.

[0006] 3. When the high-voltage battery discharge current is too low, the ISG motor cannot operate: In special scenarios, the high-voltage battery can provide high voltage and a certain current, but the discharge current cannot meet the operation of the ISG motor. At this time, the ISG motor drag speed cannot meet the starting conditions of the range extender engine. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] The present invention proposes a multi-application scenario range extender engine starting control method to solve the technical problem that the vehicle power battery of special vehicles cannot meet the high-voltage starting requirements in special usage scenarios, the special vehicle engine cannot be started and cannot be heated or generated by the engine.

[0009] (II) Technical solution

[0010] In order to solve the above technical problems, the present invention proposes a multi-application scenario range extender engine start control method, the multi-application scenario range extender engine start control method comprises the following steps:

[0011] S1. Determine the start requirement of the range extender engine

[0012] When the VCU receives the low-voltage starting signal sent by the driver through the special vehicle control panel, it verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the low-voltage starting conditions, and determines whether the low-voltage starting requirements are currently met;

[0013] When the VCU receives the high-voltage starting signal sent by the driver through the special vehicle control panel, it verifies whether there is a fault in each system of the special vehicle that prohibits the start of the range extender engine, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the high-voltage starting conditions, and determines whether the high-voltage starting requirements are met at present;

[0014] When the VCU does not receive the low-voltage start signal or high-voltage start signal sent by the driver through the special vehicle control panel, the VCU comprehensively judges the current high-voltage battery SOC, engine water temperature, driver's required power and other conditions, verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and determines whether there is a starting demand for the current range extender engine. If a starting demand is obtained, the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current are calculated to determine whether to select low-voltage start, high-voltage start or high-low voltage combined start;

[0015] S2. Range extender engine start control

[0016] After the starting demand judgment is completed, different starting demands are sent to the controller node of the special vehicle; among them, the low-voltage starting demand is sent to the ECU, and after the ECU determines whether preheating is required, it starts through the engine starter; the VCU sends the high-voltage starting demand instruction to the GCU, and at the same time the VCU determines whether it is necessary to send a preheating instruction to the ECU, and if the ECU preheating completion signal is read back after the preheating instruction is sent, the engine is started by the ISG motor; the joint starting demand is sent by the VCU to the ECU and GCU at the same time, wherein the preheating action and the engine starter are controlled by the ECU, and the ISG motor is controlled by the GCU, and the two jointly drive the engine. When the engine speed reaches the threshold, the ECU controls the engine to inject fuel for starting;

[0017] S3. Range extender engine start result determination

[0018] The VCU determines whether the engine has started successfully based on the current engine speed and torque, and outputs a successful start flag. After successful start, the range extender enters the next working state.

[0019] Furthermore, in step S1, the specific judgment process for determining whether the low-voltage starting requirement is currently met is that when the vehicle has no fault that prohibits starting the engine, the VCU first determines the low-voltage battery SOC, and when the low-voltage battery SOC ≥ the low-voltage battery SOC threshold LS1 during low-voltage starting, the VCU issues a low-voltage starting requirement to the ECU; when the low-voltage battery SOC < LS1, the VCU determines the high-voltage battery SOC and the high-voltage battery discharge current, and when the high-voltage battery SOC ≥ the high-voltage battery SOC threshold HS1 during high-voltage starting and the high-voltage battery discharge current ≥ the high-voltage battery current threshold A1 during high-voltage starting, the VCU issues a high-voltage starting requirement to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the VCU issues a joint starting requirement to the ECU and the GCU.

[0020] Furthermore, in step S1, the specific judgment process for determining whether the high-voltage starting requirement is currently met is that when the vehicle has no fault that prohibits starting the engine, the VCU first determines the high-voltage battery SOC and the high-voltage battery discharge current. When the high-voltage battery SOC ≥ HS1 and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage starting requirement to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the low-voltage battery SOC is determined. When the low-voltage battery SOC ≥ LS1, the VCU issues a low-voltage starting requirement to the ECU. When the low-voltage battery SOC < LS1, the VCU issues a joint starting requirement to the ECU and the GCU.

[0021] Further, in step S1, the specific judgment process for selecting low-voltage start, high-voltage start or high-low voltage combined start is as follows: when the driver does not issue an engine start command through the vehicle control panel, the VCU comprehensively calculates the vehicle-related parameters in real time, and when the high-voltage battery SOC is less than the SOC threshold HS2 at which the high-voltage battery needs to be externally charged or the engine water temperature is less than the water temperature threshold T1 that the engine needs to maintain during driving or the driver's required power is greater than or equal to the required power threshold P1 at which the engine needs to be started and generate electricity, it is determined that the vehicle system has a demand to start the engine at this time; when the vehicle has no fault that prohibits starting, the high-voltage battery SOC and the high-voltage battery discharge current are judged first, and when the high-voltage battery SOC ≥ HS1 and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage start demand to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the low-voltage battery SOC is judged again, and when the low-voltage battery SOC ≥ LS1, the VCU issues a low-voltage start demand to the ECU, and when the low-voltage battery SOC < LS1, the VCU issues a combined start demand to the ECU and the GCU.

[0022] Furthermore, in step S3, if the conditions for successful starting are still not met after a certain period of time has passed since the start of starting, the VCU repeats the starting according to step S2 after the engine is stopped.

[0023] Furthermore, in step S3, the number of repeated starts is modified by calibration.

[0024] Furthermore, in step S3, after the number of repeated starts exceeds a calibrated threshold, an engine start failure flag is finally output.

[0025] (III) Beneficial effects

[0026] The present invention proposes a multi-application scenario range extender engine start control method, including judging the range extender engine start demand, range extender engine start control, and range extender engine start result determination. The present invention performs high-voltage start (ISG motor), low-voltage start (engine starter) or high-low voltage combined start according to external driver request and internal software strategy, and can meet the range extender engine start demand for different application scenarios, so as to meet various usage scenarios of special vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the engine starting flowchart for the current mainstream extended-range hybrid vehicle;

[0028] Figure 2 This is a flow chart for judging the low-voltage starting demand in the present invention;

[0029] Figure 3 This is a flow chart of high-voltage starting demand determination in the present invention;

[0030] Figure 4 This is a flow chart of VCU judging the starting requirement in the present invention;

[0031] Figure 5 This is a control flow chart of the startup process in the present invention;

[0032] Figure 6 This is a control flow chart of successful start and failed start in the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0034] This embodiment proposes a multi-application scenario range extender engine start control method, which specifically includes the following steps:

[0035] S1. Determine the start requirement of the range extender engine

[0036] When the VCU receives the low-voltage start signal sent by the driver through the special vehicle control panel, it verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the low-voltage start conditions, and determines whether the low-voltage start requirements are currently met. The specific judgment process is as follows: Figure 2 As shown, when the vehicle has no fault that prohibits starting the engine, the VCU first determines the low-voltage battery SOC. When the low-voltage battery SOC is ≥ the low-voltage battery SOC threshold LS1 (calibrable) at low-voltage starting, the VCU issues a low-voltage starting request to the ECU; when the low-voltage battery SOC is < LS1 (calibrable), the VCU determines the high-voltage battery SOC and the high-voltage battery discharge current. When the high-voltage battery SOC is ≥ the high-voltage battery SOC threshold HS1 (calibrable) at high-voltage starting and the high-voltage battery discharge current is ≥ the high-voltage battery current threshold A1 at high-voltage starting, the VCU issues a high-voltage starting request to the GCU; when the high-voltage battery SOC is < HS1 (calibrable) or the high-voltage battery discharge current is < A1, the VCU issues a joint starting request to the ECU and the GCU.

[0037] When the VCU receives the high-voltage start signal sent by the driver through the special vehicle control panel, it verifies whether there are faults in the special vehicle systems that prohibit the range extender engine from starting, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the high-voltage start conditions, and determines whether the current high-voltage start requirements are met. The specific judgment process is as follows: Figure 3As shown, when the vehicle has no fault that prohibits starting the engine, the VCU first determines the high-voltage battery SOC and the high-voltage battery discharge current. When the high-voltage battery SOC ≥ HS1 (calibrable) and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage starting request to the GCU; when the high-voltage battery SOC < HS1 (calibrable) or the high-voltage battery discharge current < A1, the low-voltage battery SOC is determined. When the low-voltage battery SOC ≥ LS1 (calibrable), the VCU issues a low-voltage starting request to the ECU. When the low-voltage battery SOC < LS1 (calibrable), the VCU issues a joint starting request to the ECU and the GCU.

[0038] When the VCU does not receive the low-voltage start signal or high-voltage start signal sent by the driver through the special vehicle control panel, the VCU comprehensively judges the current high-voltage battery SOC, engine water temperature, driver's required power and other conditions, verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and determines whether the current range extender engine has a starting demand. If a starting demand is obtained, the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current are calculated to determine whether to select low-voltage start, high-voltage start or high-low voltage combined start. The specific judgment process is as follows Figure 4 As shown, when the driver does not issue an engine start command through the vehicle control panel, the VCU comprehensively calculates the vehicle-related parameters in real time. When the high-voltage battery SOC is less than the SOC threshold HS2 (calibrable) at which the high-voltage battery needs to be externally charged or the engine water temperature is less than the water temperature threshold T1 (calibrable) that the engine needs to maintain during driving or the driver's required power is greater than or equal to the required power threshold P1 (calibrable) that requires the engine to start and generate electricity, it is determined that the vehicle system has a need to start the engine at this time; when the vehicle has no fault that prohibits starting, the high-voltage battery SOC and the high-voltage battery discharge current are determined first. When the high-voltage battery SOC ≥ HS1 (calibrable) and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage start request to the GCU; when the high-voltage battery SOC < HS1 (calibrable) or the high-voltage battery discharge current < A1, the low-voltage battery SOC is determined again. When the low-voltage battery SOC ≥ LS1 (calibrable), the VCU issues a low-voltage start request to the ECU. When the low-voltage battery SOC < LS1 (calibrable), the VCU issues a joint start request to the ECU and the GCU.

[0039] S2. Range extender engine start control

[0040] like Figure 5As shown in the figure, after the starting demand judgment is completed, different starting demands are sent to the controller nodes related to special vehicles. Among them, the low-voltage starting demand is sent to the ECU, and the ECU judges whether preheating is required and starts through the engine starter; the VCU sends the high-voltage starting demand instruction to the GCU, and the VCU judges whether it is necessary to send a preheating instruction to the ECU, and if the ECU preheating completion signal is read back after sending the preheating instruction, the engine is started by the ISG motor; the joint starting demand is sent by the VCU to the ECU and GCU at the same time, in which the preheating action and the engine starter are controlled by the ECU, and the ISG motor is controlled by the GCU, and the two jointly drag the engine. When the engine speed reaches a certain threshold, the ECU controls the engine to inject fuel for starting.

[0041] S3. Range extender engine start result determination

[0042] like Figure 6 As shown, the VCU determines whether the engine is started successfully based on the current engine speed and torque, and outputs a successful start flag; after successful start, the range extender enters the next working state; if the conditions for successful start are still not met after a certain period of time after the start, the VCU repeats the start according to step S2 after the engine is stopped, and the number of repeated starts can be modified by calibration; after the number of repeated starts exceeds the calibration threshold, the engine start failure flag is finally output.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-application scenario range extender engine start control method, characterized in that: The multi-application scenario range extender engine start control method comprises the following steps: S1. Determine the start requirement of the range extender engine When the VCU receives the low-voltage starting signal sent by the driver through the special vehicle control panel, it verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the low-voltage starting conditions, and determines whether the low-voltage starting requirements are currently met; When the VCU receives the high-voltage starting signal sent by the driver through the special vehicle control panel, it verifies whether there is a fault in each system of the special vehicle that prohibits the start of the range extender engine, and calculates whether the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current meet the high-voltage starting conditions, and determines whether the high-voltage starting requirements are met at present; When the VCU does not receive the low-voltage start signal or high-voltage start signal sent by the driver through the special vehicle control panel, the VCU comprehensively judges the current high-voltage battery SOC, engine water temperature, driver's required power and other conditions, verifies whether there is a fault in the special vehicle system that prohibits the range extender engine from starting, and determines whether there is a starting demand for the current range extender engine. If a starting demand is obtained, the low-voltage battery SOC, high-voltage battery SOC and high-voltage battery available discharge current are calculated to determine whether to select low-voltage start, high-voltage start or high-low voltage combined start; S2. Range extender engine start control After the starting demand judgment is completed, different starting demands are sent to the controller node of the special vehicle; among them, the low-voltage starting demand is sent to the ECU, and after the ECU determines whether preheating is required, it starts through the engine starter; the VCU sends the high-voltage starting demand instruction to the GCU, and at the same time the VCU determines whether it is necessary to send a preheating instruction to the ECU, and if the ECU preheating completion signal is read back after the preheating instruction is sent, the engine is started by the ISG motor; the joint starting demand is sent by the VCU to the ECU and GCU at the same time, wherein the preheating action and the engine starter are controlled by the ECU, and the ISG motor is controlled by the GCU, and the two jointly drive the engine. When the engine speed reaches the threshold, the ECU controls the engine to inject fuel for starting; S3. Range extender engine start result determination The VCU determines whether the engine has started successfully based on the current engine speed and torque, and outputs a successful start flag. After successful start, the range extender enters the next working state.

2. The multi-application scenario range extender engine start control method according to claim 1, characterized in that: In step S1, the specific judgment process for determining whether the low-voltage starting requirement is currently met is that when the vehicle has no fault that prohibits starting the engine, the VCU first determines the low-voltage battery SOC. When the low-voltage battery SOC ≥ the low-voltage battery SOC threshold LS1 during low-voltage starting, the VCU issues a low-voltage starting requirement to the ECU; when the low-voltage battery SOC < LS1, the VCU determines the high-voltage battery SOC and the high-voltage battery discharge current. When the high-voltage battery SOC ≥ the high-voltage battery SOC threshold HS1 during high-voltage starting and the high-voltage battery discharge current ≥ the high-voltage battery current threshold A1 during high-voltage starting, the VCU issues a high-voltage starting requirement to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the VCU issues a joint starting requirement to the ECU and the GCU.

3. The multi-application scenario range extender engine start control method according to claim 1, characterized in that: In step S1, the specific judgment process for determining whether the high-voltage starting requirement is currently met is that when the vehicle has no fault that prohibits starting the engine, the VCU first determines the high-voltage battery SOC and the high-voltage battery discharge current. When the high-voltage battery SOC ≥ HS1 and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage starting requirement to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the low-voltage battery SOC is determined. When the low-voltage battery SOC ≥ LS1, the VCU issues a low-voltage starting requirement to the ECU. When the low-voltage battery SOC < LS1, the VCU issues a joint starting requirement to the ECU and the GCU.

4. The multi-application scenario range extender engine start control method according to claim 1, characterized in that: In step S1, the specific judgment process for selecting low-voltage start, high-voltage start or high-low voltage combined start is as follows: when the driver does not issue an engine start command through the vehicle control panel, the VCU comprehensively calculates the vehicle-related parameters in real time, and when the high-voltage battery SOC is less than the SOC threshold HS2 at which the high-voltage battery needs to be externally charged or the engine water temperature is less than the water temperature threshold T1 that the engine needs to maintain during driving or the driver's required power is greater than or equal to the required power threshold P1 at which the engine needs to be started and generate electricity, it is determined that the vehicle system has a demand to start the engine at this time; when the vehicle has no fault that prohibits starting, the high-voltage battery SOC and the high-voltage battery discharge current are judged first, and when the high-voltage battery SOC ≥ HS1 and the high-voltage battery discharge current ≥ A1, the VCU issues a high-voltage start demand to the GCU; when the high-voltage battery SOC < HS1 or the high-voltage battery discharge current < A1, the low-voltage battery SOC is judged again, and when the low-voltage battery SOC ≥ LS1, the VCU issues a low-voltage start demand to the ECU, and when the low-voltage battery SOC < LS1, the VCU issues a combined start demand to the ECU and the GCU.

5. The multi-application scenario range extender engine start control method according to claim 1, characterized in that: In step S3, if the conditions for successful starting are still not met after a certain period of time has passed since the start of starting, the VCU will repeat the starting according to step S2 after the engine is stopped.

6. The multi-application scenario range extender engine start control method according to claim 5, characterized in that: In step S3, the number of repeated starts is modified by calibration.

7. The multi-application scenario range extender engine start control method according to claim 1, characterized in that: In step S3, after the number of repeated starts exceeds the calibrated threshold, an engine start failure flag is finally output.

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