Cold start system, control method, control system and vehicle for methanol engine

Abstract

The present invention relates to a cold start system, control method, control system and vehicle for a methanol engine, so as to solve the technical problem that the cold start of a methanol hybrid vehicle requires the setting of a heating auxiliary system, which leads to an increase in vehicle hardware and high design cost. The system includes a first circulation flow path arranged between a drive motor, an electronic thermostat and a methanol engine, and a second circulation flow path between the drive motor, the electronic thermostat, the radiator and the methanol engine. The method includes: 1. Starting the drive motor, if T1<T0, entering step S2; if T1≥T0, entering step S3; 2. Making the temperature of the methanol engine reach T2 through the first circulation flow path, and T2≥T0; 3. Performing a methanol engine cold start procedure, and ending if successful; if unsuccessful, continuing to operate in pure electric mode for a time interval of t1, and performing a cold start again, until the methanol engine starts successfully.

Description

Technical Field

[0001] The invention relates to a cold start method for a methanol hybrid vehicle, and in particular to a cold start system, a control method, a control system and a vehicle for a methanol engine. Background Art

[0002] The latent heat of vaporization of methanol fuel is about 4 times that of gasoline. Methanol fuel needs to absorb a large amount of heat when it vaporizes to form a mixed gas. When the temperature is low, methanol engine fuel is difficult to atomize and adhere to the intake pipe, resulting in the mixture being too lean and unable to start the engine.

[0003] Currently, the methanol engine cold start technologies that are commercially available mainly include methanol fuel evaporation preheating and intake air electric heating technology. All of the above methods require a separate heating auxiliary system to solve the problem, resulting in high costs for vehicle system hardware modification and design.

[0004] A Chinese patent with publication number CN 114109689A discloses a cold start control method and control system for a methanol engine, wherein an intake manifold heater is arranged outside the intake manifold to heat the gas in the intake manifold, an intake manifold heater is arranged outside the intake manifold to heat the gas in the intake manifold, a coolant heater heats the coolant circulating in the cooling system, and then the heated coolant circulates in the coolant flow channel in the engine body, thereby heating the engine body; the patent realizes preheating of the methanol engine through multiple heating auxiliary systems, which increases the design cost. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the cold start of the current methanol hybrid vehicle requires the installation of a heating auxiliary system, which leads to an increase in vehicle hardware and high design costs, and proposes a cold start system, control method, control system and vehicle for a methanol engine.

[0006] The technical solution provided by the present invention is:

[0007] A cold start system for a methanol engine, which is special in that it includes a circulation pipeline, a methanol engine, a clutch, a drive motor, a radiator and an electronic thermostat;

[0008] The methanol engine, the clutch and the drive motor are arranged in sequence along the power transmission direction, and the drive motor is used to connect with the gearbox;

[0009] The circulation pipeline includes a motor outlet section, a radiator inlet section, a radiator outlet section, a methanol engine inlet section, a methanol engine pipeline section, a motor inlet section and a motor pipeline section; one end of the motor outlet section is connected to the input end of the electronic thermostat, and the other end is connected to the outlet of the motor pipeline section, one end of the radiator inlet section and one end of the methanol engine inlet section are respectively connected to two output ends of the electronic thermostat, the other end of the radiator inlet section is connected to the inlet of the radiator, and the other end of the methanol engine inlet section is connected to the inlet of the methanol engine pipeline section; the outlet of the radiator is connected to the inlet of the methanol engine pipeline section through the radiator outlet section, and the outlet of the methanol engine pipeline section is connected to the inlet of the motor pipeline section through the motor inlet section;

[0010] The circulation pipeline forms a first circulation flow path and a second circulation flow path. The coolant in the first circulation flow path passes through the drive motor and the electronic thermostat and enters the methanol engine, which is used to heat the coolant by utilizing the waste heat generated during the operation of the drive motor, and then heats the methanol engine. The coolant in the second circulation flow path passes through the drive motor, the electronic thermostat, and the radiator and enters the methanol engine, which is used to cool the coolant when the coolant reaches a preset cooling temperature. Furthermore, a pump wheel is provided at the entrance of the methanol engine pipeline section, which is used to accelerate the flow rate of the coolant entering the methanol engine pipeline section.

[0011] The present invention also provides a cold start control method for a methanol engine, which is special in that the cold start control method for a methanol engine is used, and includes the following steps:

[0012] S1, start the drive motor and run it in pure electric mode, read the current temperature T1 of the methanol engine, and compare it with the preset starting temperature T0. If T1<T0, go to step S2; if T1≥T0, go to step S3;

[0013] S2, controlling the coolant to run in the first circulation flow path through the electronic thermostat, absorbing the heat generated by the drive motor by the coolant to heat the methanol engine until the temperature of the methanol engine reaches T2, and T2 ≥ T0, and then proceeding to step S3;

[0014] S3, running the methanol engine cold start program, controlling the clutch to engage with the drive motor, using the drive motor to drag the methanol engine to rotate, so as to realize the ignition start of the methanol engine. If the ignition start of the methanol engine is successful, the cold start program ends; if the ignition start of the methanol engine is unsuccessful, entering step S4;

[0015] S4, repeat the cold start procedure

[0016] S4.1 controls the clutch to separate from the drive motor, and the drive motor continues to operate in pure electric mode, with a preset operating time of t1;

[0017] S4.2 When the running time is greater than or equal to t1, the methanol engine cold start procedure is performed again;

[0018] If the methanol engine cold start procedure is successfully performed again, the cold start procedure ends;

[0019] If the methanol engine cold start procedure is unsuccessful again and the number of repeated cold starts is less than or equal to the preset number, return to step S4.1 until the methanol engine ignites and starts successfully; if the number of times returning to step S4.1 is greater than the preset number and still unsuccessful, abandon the cold start procedure and perform a fault check.

[0020] Furthermore, in step S4, after the methanol engine is successfully ignited, the coolant still circulates in the first circulation path. When the coolant temperature is greater than or equal to T3, T3 is the preset cooling temperature and T3>T2, the electronic thermostat is controlled to switch the coolant into the radiator inlet section, and the second circulation path is opened to take away the heat generated by the methanol engine and the drive motor through the radiator.

[0021] Furthermore, in step S4.2, the preset number of times is 3-5 times.

[0022] Furthermore, in step S1, the preset starting temperature T0 is 18-25°C.

[0023] Furthermore, in step S4, the preset running time t1 is 2-4 minutes.

[0024] The present invention also provides a cold start control system for a methanol engine, which is special in that it includes a memory and a processor, wherein a control program is stored in the memory, and when the control program is executed by the processor, it is used to implement the cold start control method of the methanol engine.

[0025] The present invention also provides a vehicle, which is special in that it comprises the above-mentioned cold start control system for a methanol engine.

[0026] Beneficial effects of the present invention:

[0027] 1. The present invention can effectively alleviate the cold start problem of the methanol engine by setting an electronic thermostat and a circulation pipeline and driving the methanol engine to start by a driving motor. Compared with other methanol engine cold start technologies, it does not need to set up a separate heating auxiliary system, and the modification and design costs are lower.

[0028] 2. The cold start control method of the methanol engine provided by the present invention improves the cold start performance of the methanol engine, expands the application scope of methanol fuel in the transportation industry, and reduces dependence on imported petroleum products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of an embodiment of a cold start system for a methanol engine according to the present invention;

[0030] Figure 2 The present invention is a flow chart of an embodiment of a cold start control method for a methanol engine.

[0031] The reference numerals are as follows:

[0032] 1-circulation pipeline, 101-motor outlet section, 102-radiator inlet section, 103-radiator outlet section, 104-methanol engine inlet section, 105-methanol engine pipeline section, 106-motor inlet section, 2-methanol engine, 3-clutch, 4-drive motor, 5-radiator, 6-pump wheel, 7-electronic thermostat, 8-gearbox. DETAILED DESCRIPTION

[0033] See also Figure 1 The present embodiment provides a cold start system for a methanol engine, the system comprising a circulation pipeline 1, a methanol engine 2, a clutch 3, a drive motor 4, a radiator 5 and an electronic thermostat 7.

[0034] The methanol engine 2 , the clutch 3 and the drive motor 4 are arranged in sequence along the power transmission direction, and the drive motor 4 is used to be connected to the gearbox 8 .

[0035] The circulation pipeline 1 includes a motor outlet section 101, a radiator inlet section 102, a radiator outlet section 103, a methanol engine inlet section 104, a methanol engine pipeline section 105, a motor inlet section 106 and a motor pipeline section; one end of the motor outlet section 101 is connected to the input end of the electronic thermostat 7, and the other end is connected to the outlet of the motor pipeline section, one end of the radiator inlet section 102 and one end of the methanol engine inlet section 104 are respectively connected to the two output ends of the electronic thermostat 7, and the radiator inlet section 10 The other end of the methanol engine inlet section 104 is connected to the inlet of the methanol engine pipeline section 105; the outlet of the radiator 5 is connected to the inlet of the methanol engine pipeline section 105 through the radiator outlet section 103, and the outlet of the methanol engine pipeline section 105 is connected to the inlet of the motor pipeline section through the motor inlet section 106; a pump wheel 6 is provided at the inlet of the methanol engine pipeline section 105 to accelerate the flow rate of the coolant entering the methanol engine pipeline section 105.

[0036] The circulation pipeline 1 is composed of a first circulation flow path and a second circulation flow path. The first circulation flow path includes a motor pipeline section, a motor outlet section 101, an electronic thermostat 7, a methanol engine inlet section 104, a methanol engine pipeline section 105 and a motor inlet section 106 connected end to end in sequence, and is used to utilize the waste heat generated during the operation of the drive motor 4 to heat the coolant, thereby heating the methanol engine 2; the second circulation flow path includes a motor pipeline section, a motor outlet section 101, a radiator inlet section 102, a radiator 5, a radiator outlet section 103, a methanol engine pipeline section 105 and a motor inlet section 106 connected end to end in sequence, and is used to cool the coolant when the coolant reaches a preset cooling temperature.

[0037] Taking the start of a parallel methanol hybrid vehicle in a low-temperature environment as an example, the methanol engine 2 is affected by the low-temperature environment and the body temperature is also low. The fuel injected by the methanol engine 2 is difficult to atomize, and the mixture is too lean, which will make it difficult to start the methanol engine 2. Before the engine is started at low temperature, the vehicle control system controls the electronic thermostat 7 to allow the coolant to flow in the first circulation path composed of the engine and the motor. The parallel methanol hybrid vehicle first starts and accelerates in pure electric mode, and uses the waste heat generated during the operation of the drive motor 4 to heat the coolant. The coolant flows in the first circulation path, and the temperature of the methanol engine 2 body is gradually heated and increased.

[0038] During operation in pure electric mode, when the methanol engine 2 completes preheating and meets the preset starting temperature requirement, the vehicle control system controls the clutch 3 to engage, and drives the methanol engine 2 through the drive motor 4 to start and ignite. The drive motor 4 has a large power, and during the driving process, the methanol engine 2 is started by closing the clutch 3, which can provide sufficient power to overcome the friction resistance during the starting process of the methanol engine 2 and ensure a sufficient number of ignitions. The cold start control method can further improve the cold start performance of the methanol engine 2 in a low temperature environment.

[0039] After the engine cold start is completed, as the drive system runs, when the coolant temperature reaches the preset cooling temperature or the drive system overheats and needs cooling, the vehicle control system controls the electronic thermostat 7 to change the coolant flow direction so that the coolant flows in the second circulation path composed of the radiator 5, the methanol engine 2 and the drive motor 4.

[0040] The vehicle controller controls the electronic thermostat 7 to change the flow direction of the coolant to realize two cooling circulation flow paths, the first circulation flow path and the second circulation flow path. The first circulation flow path can meet the preheating requirements of the engine body before the methanol engine 2 is started in a low temperature environment, and helps to vaporize the methanol fuel injected when the methanol engine 2 is started. The second circulation flow path can meet the heat dissipation requirements of the power system during the continuous operation of the vehicle. This embodiment can effectively alleviate the cold start problem of the methanol engine 2 by adding an electronic thermostat 7 and a cooling system design, and using a control method to drive the methanol engine 2 to start by driving the motor 4. Compared with other cold start technologies of the methanol engine 2, there is no need to set up a separate heating auxiliary system, and the modification and design costs are relatively low.

[0041] See also Figure 2 The control process of the cold start system for a methanol engine comprises the following steps:

[0042] S1. Start the drive motor 4 and operate in pure electric mode. At this time, the clutch 3 is separated from the drive motor 4, the methanol engine 2 is in a shutdown state, and the vehicle is driven by the drive motor 4 to operate; read the current temperature T1 of the methanol engine 2 and compare it with the preset starting temperature T0, the preset starting temperature T0 is 18-25°C; if T1<T0, go to step S2; if T1≥T0, go to step S3; wherein, a temperature sensor is provided inside the methanol engine 2, and the temperature sensor can be used to collect the internal temperature of the methanol engine 2.

[0043] S2, the coolant is controlled to flow from direction A to direction C by the electronic thermostat 7, so as to run in the first circulation flow path, and the heat generated during the operation of the drive motor 4 is absorbed by the coolant, and the coolant passes through the motor pipeline section, the motor outlet section 101, the electronic thermostat 7, the methanol engine inlet section 104, the methanol engine pipeline section 105, and the motor inlet section 106 in sequence, and the coolant flows in the first circulation flow path connecting the methanol engine 2 and the drive motor 4, and the temperature of the methanol engine 2 body is preheated and increased; until the temperature of the methanol engine 2 is T2, and T2 ≥ T0, then enter step S3;

[0044] S3, running the cold start procedure of the methanol engine 2, controlling the clutch 3 to engage with the drive motor 4, using the drive motor 4 to drag the methanol engine 2 to rotate, so as to realize the ignition start of the methanol engine 2. If the ignition start of the methanol engine 2 is successful, the cold start procedure is completed, and the methanol engine 2 provides power to drive the gearbox 8 to operate; if the ignition start of the methanol engine 2 is unsuccessful, entering step S4;

[0045] S4, repeat the cold start procedure

[0046] S4.1 controls the clutch 3 to separate from the drive motor 4, and the drive motor 4 continues to operate in the pure electric mode, and the preset operating time is t1, and the preset operating time t1 is 2-4 minutes;

[0047] S4.2 When the running time is greater than or equal to t1 and the current temperature of the methanol engine 2 is greater than or equal to T0, the methanol engine 2 cold start procedure is performed again;

[0048] If the cold start procedure of the methanol engine 2 is successfully performed again, the cold start procedure ends;

[0049] If the cold start procedure of the methanol engine 2 is unsuccessful again and the number of repeated cold starts is less than the preset number, return to step S4.1 until the methanol engine 2 is successfully ignited and start, and enter step S5; if the number of times returning to step S4.1 is greater than 5 times and still unsuccessful, abandon the cold start procedure and perform a fault check.

[0050] S5. For a period of time after the methanol engine 2 is successfully ignited and started, the coolant still circulates in the first circulation flow path. When the coolant temperature is greater than or equal to T3, T3 is the preset cooling temperature and T3>T2, the electronic thermostat 7 is controlled to switch the coolant so that the coolant flows from direction A to direction B and enters the radiator inlet section 102, and the second circulation flow path is opened. At this time, the heat generated by the methanol engine 2 and the motor during operation is absorbed by the coolant, and the coolant passes through the motor pipeline section connected end to end, the motor outlet section 101, the radiator inlet section 102, the radiator 5, the radiator outlet section 103, the methanol engine pipeline section 105 and the motor inlet section 106 in sequence. The coolant circulates in the second circulation flow path connecting the methanol engine 2, the radiator 5 and the drive motor 4, and the coolant temperature is reduced through the radiator 5 to achieve the heat dissipation requirements of the power system components.

[0051] The present invention also provides a cold start control system for a methanol engine, the control system includes a memory and a processor, the memory stores a control program, and the control program is used to implement the cold start control method of the methanol engine when executed by the processor; the present invention also provides a vehicle including the cold start control system for a methanol engine.

Claims

1. A cold start control method for a methanol engine, using a cold start system for a methanol engine, wherein the cold start system for the methanol engine comprises a circulation pipeline (1), a methanol engine (2), a clutch (3), a drive motor (4), a radiator (5) and an electronic thermostat (7); The methanol engine (2), the clutch (3) and the drive motor (4) are arranged in sequence along the power transmission direction, and the drive motor (4) is used to be connected to the gearbox (8); The circulation pipeline (1) comprises a motor outlet section (101), a radiator inlet section (102), a radiator outlet section (103), a methanol engine inlet section (104), a methanol engine pipeline section (105), a motor inlet section (106) and a motor pipeline section; one end of the motor outlet section (101) is connected to the input end of the electronic thermostat (7), and the other end is connected to the outlet of the motor pipeline section; one end of the radiator inlet section (102) and one end of the methanol engine inlet section (104) are connected to each other. They are respectively connected to the two output ends of the electronic thermostat (7), the other end of the radiator inlet section (102) is connected to the inlet of the radiator (5), and the other end of the methanol engine inlet section (104) is connected to the inlet of the methanol engine pipeline section (105); the outlet of the radiator (5) is connected to the inlet of the methanol engine pipeline section (105) through the radiator outlet section (103), and the outlet of the methanol engine pipeline section (105) is connected to the inlet of the motor pipeline section through the motor inlet section (106); The circulation pipeline (1) forms a first circulation flow path and a second circulation flow path, and the coolant in the first circulation flow path passes through the drive motor (4) and the electronic thermostat (7) and enters the methanol engine (2), and is used to utilize the waste heat generated during the operation of the drive motor (4) to heat the coolant, thereby heating the methanol engine (2); The coolant in the second circulation flow path enters the methanol engine (2) through the drive motor (4), the electronic thermostat (7) and the radiator (5), and is used to cool the coolant when the coolant reaches a preset cooling temperature; It is characterized by comprising the following steps: S1, start the drive motor (4), run in pure electric mode, read the current temperature T1 of the methanol engine (2), compare it with the preset starting temperature T0, if T1 < T0, go to step S2; if T1 ≥ T0, go to step S3; the preset starting temperature T0 is 18-25°C; S2, controlling the coolant to run in the first circulation flow path through the electronic thermostat (7), absorbing the heat generated by the drive motor (4) by the coolant to heat the methanol engine (2), until the temperature of the methanol engine (2) is T2, and T2 ≥ T0, and then entering step S3; S3, running the cold start procedure of the methanol engine (2), controlling the clutch (3) to engage with the drive motor (4), using the drive motor (4) to drive the methanol engine (2) to rotate, so as to realize the ignition start of the methanol engine (2); if the ignition start of the methanol engine (2) is successful, the cold start procedure ends; if the ignition start of the methanol engine (2) is unsuccessful, entering step S4; S4, repeat the cold start procedure S4.1 controls the clutch (3) to separate from the drive motor (4), and uses the drive motor (4) to continue to operate in the pure electric mode, and the preset operating time is t1; the preset operating time t1 is 2-4 minutes; S4.2 When the running time is greater than or equal to t1, the methanol engine (2) cold start procedure is performed again; If the cold start procedure of the methanol engine (2) is successfully performed again, the cold start procedure ends; If the cold start procedure of the methanol engine (2) is not successful again, and the number of repeated cold starts is less than or equal to a preset number of times, the process returns to step S4.1 until the methanol engine (2) is successfully ignited and started; if the number of times the process returns to step S4.1 is greater than a preset number of times and still unsuccessful, the cold start procedure is abandoned and a fault check is performed; the preset number of times is 3-5 times; After the methanol engine (2) is successfully ignited and started, the coolant still circulates in the first circulation flow path. When the coolant temperature is greater than or equal to T3, T3 is a preset cooling temperature and T3>T2, the electronic thermostat (7) is controlled to switch the coolant into the radiator inlet section (102), the second circulation flow path is opened, and the heat generated by the methanol engine (2) and the drive motor (4) is taken away through the radiator (5).

2. The cold start control method according to claim 1, characterized in that: A pump wheel (6) is provided at the inlet of the methanol engine pipeline section (105) for accelerating the flow rate of the coolant entering the methanol engine pipeline section (105).

3. A cold start control system for a methanol engine, characterized in that: It comprises a memory and a processor, wherein a control program is stored in the memory, and when the control program is executed by the processor, it is used to implement the cold start control method described in any one of claims 1 or 2.

4. A vehicle, characterized in that: Including the cold start control system for a methanol engine as described in claim 3.

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