CN111169328B - A fuel cell control method for passenger cars - Google Patents

Abstract

The invention relates to a control method of a fuel cell for a passenger car, which comprises the following steps: 1) starting the vehicle; 2) receiving a stack starting command; 3) acquiring the SOC value of the current power battery, judging whether the SOC value is not greater than a threshold value a, if so, sending an FC ON command, and if not, stopping the power battery; 4) comparing the SOC value with a threshold value b, 41) when b is larger than SOC and smaller than or equal to a, sending a target power x by the vehicle-mounted VCU, and carrying out step 5); 42) when the SOC is less than or equal to b, the vehicle-mounted VCU sends out target power y, and the step 7) is carried out; 5) comparing the SOC value with a threshold value c, when a is larger than SOC and smaller than or equal to c, sending out target power z, and performing the step 6), otherwise, returning to the step 4); 6) when the SOC is larger than or equal to c, the FCU responds to shutdown; 7) and comparing with a threshold value d, when the SOC is larger than or equal to d, sending out target power x by the vehicle-mounted VCU, and performing the step 5), otherwise, returning to the step 42). Compared with the prior art, the invention has the advantages of safe operation, high safety performance, improved fuel utilization rate, quick energy charging and the like.

Description

A fuel cell control method for passenger cars

technical field

The invention relates to the field of motor vehicle fuel cell control, in particular to a fuel cell control method for passenger vehicles.

Background technique

The country's requirements for motor vehicle emission standards are getting higher and higher. The diesel internal combustion engine used in the passenger car industry emits more waste pollution. It needs a zero-emission, zero-pollution, more low-carbon and environmentally friendly sustainable energy to solve the problem of environmental pollution. .

The development of new energy vehicles is guided by a series of favorable policies of the state, and the technology development is becoming more and more mature. The repeated improvement of the energy density of power batteries has continuously improved the cruising range of the vehicles. However, pure electric vehicles can only cover urban buses and short-distance travel routes at present. The demand for long-distance transportation is still dominated by traditional diesel vehicles, and there is a gap in the market.

Since General Motors launched the world's first fuel cell vehicle in 1966, with the rapid improvement of fuel cell technology, the improvement of hydrogen energy storage and hydrogen refueling station construction, and the integration of fuel cells, various factors conducive to the industrialization of fuel cell vehicles have developed. The conditions are gradually fulfilled, and the development climax of the third round of fuel cell vehicles has arrived. Fuel cell models from many international automakers, including Toyota, Honda, Mercedes-Benz, GM, Hyundai, Ford, BMW, etc., will be launched intensively in 2016-2018. "Made in China 2025" proposes "energy-saving and new energy vehicles" as a key development area. Point out the direction for the development of fuel cell vehicles in my country. The working reaction rate of the fuel cell engine cannot achieve the power response to failure like the internal combustion engine and pure electric motor, and there is a certain hysteresis. At this time, a control strategy is needed to meet the coupling between the fuel cell engine and the power battery to meet the driving force. The operation of the motor achieves the smooth operation of the vehicle.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a fuel cell control method for passenger cars in order to overcome the above-mentioned defects of the prior art.

The object of the present invention can be realized through the following technical solutions:

A fuel cell control method for a passenger car is used to realize the uninterrupted parallel coupling operation of a fuel cell and a pure electric battery, comprising the following steps:

1) When the vehicle starts, the on-board VCU starts to power on and sends a ready signal;

2) The on-board VCU receives the stack start command that the fuel cell stack switch is turned on;

3) The vehicle-mounted VCU obtains the SOC value of the current power battery, and judges whether it is not greater than the first threshold a, if so, issue an FC ON command, and go to step 4), if not, make the fuel cell in a shutdown state;

4) The on-board FCU (fuel cell controller) issues a command to allow loading power after self-checking, and compares the SOC value with the second threshold b, specifically:

41) When b<SOC≤a, the vehicle-mounted VCU sends the first target power x to the FCU, and the FCU responds and proceeds to step 5);

42) When SOC≤b, the vehicle-mounted VCU sends the second target power y to the FCU, and the FCU responds and proceeds to step 7);

5) Compare the SOC value with the third threshold value c, when a<SOC≤c, the vehicle-mounted VCU sends the third target power z to the FCU, and the FCU responds to step 6), otherwise, return to step 4);

6) When SOC≥c, the vehicle-mounted VCU issues an FC OFF command, the FCU responds to shutdown, and the fuel cell is in a shutdown state;

7) Compare the SOC value with the fourth threshold d, when SOC≥d, the on-board VCU sends the first target power x to the FCU, and the FCU responds to step 5), otherwise, return to step 42).

In the step 4), if the on-board FCU self-check finds a fault, then the on-board VCU receives the fault alarm information of the FCU and processes it according to the level of the fault.

The magnitude relationship of the first threshold a, the second threshold b, the third threshold c, and the fourth threshold d is b<d<a<c.

The first threshold value a is 86%, the second threshold b is 60%, the third threshold c is 90%, and the fourth threshold d is 65%.

The magnitude relationship between the first target power x, the second target power y, and the third target power z is z<x<y.

The value of the first target power x is 10kW, the value of the second target power y is 30kW, and the value of the third target power z is 3kW.

The front of the fuel cell stack switch is provided with the word H ₂ and an anti-reset mechanism.

Compared with the prior art, the present invention has the following advantages:

1) Operation safety: The present invention adopts the size of a conventional rocker switch, which is convenient for the driver to use, and the front of the switch adopts the striking " _H2 " word, and the lock is not reset to prevent accidental closing;

2) High safety performance: first low-voltage power-on and then high-voltage power-on, high-voltage power-on after the completion of the hydrogen concentration detection, effectively protects the safety performance of the vehicle;

3) Improve the fuel utilization rate: in the case of different power battery SOC values, the fuel cell system is required to output corresponding power without causing energy waste of the fuel cell system;

4) Fast charging: The use of hydrogen as an energy source is shorter than the charging time of conventional power batteries. It only takes ten minutes to fill up with hydrogen to drive again, which greatly improves the cruising range of pure electric vehicles.

Description of drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a schematic structural diagram of a fuel cell stack switch.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example

As shown in FIG. 1 , the present invention provides a fuel cell control method for a passenger car, how to couple the fuel cell and the pure electric battery to work in parallel, so that the vehicle can run smoothly without power interruption, and the energy recovery process will not cause fuel failure. A series of faults such as overcharging of the battery and engine.

The present invention specifically includes the following steps:

1) When the vehicle starts, the on-board VCU starts to power on and sends a ready signal;

2) The on-board VCU receives the stack start command that the fuel cell stack switch is turned on;

3) The vehicle-mounted VCU obtains the SOC value of the current power battery, and judges whether it is not greater than the first threshold a (86% in this example), if so, issue the FC ON command and go to step 4), if not, make The fuel cell is in a shutdown state;

4) After the self-check, the on-board FCU issues a command to allow loading of power, and compares the SOC value with the second threshold b (60% in this example), specifically:

41) When b<SOC≤a, the on-board VCU sends a first target power of 10kW to the FCU, and the FCU responds and proceeds to step 5);

42) When SOC≤b, the on-board VCU sends a second target power of 30kW to the FCU, and the FCU responds and proceeds to step 7);

5) Compare the SOC value with the third threshold value c (90% in this example), when a<SOC≤c, the on-board VCU sends a third target power of 3kW to the FCU, and the FCU responds to step 6), otherwise , return to step 4);

6) When SOC≥c, the vehicle-mounted VCU issues an FC OFF command, the FCU responds to shutdown, and the fuel cell is in a shutdown state;

7) Compare the SOC value with the fourth threshold d (value 65% in this example), when the SOC ≥ d, the on-board VCU sends the first target power 10kW to the FCU, and the FCU responds to step 5), otherwise, Return to step 42).

After the low-voltage power-on of the vehicle is completed, the vehicle controller will logically determine that the vehicle is free of any faults and then power on the high-voltage. This process is expected to wait 5 seconds before the vehicle can drive normally, because adding a fuel cell system requires hydrogen concentration detection. It is necessary to increase the detection time of 30 seconds to ensure the normal operation of the fuel cell engine.

Because the hydrogen concentration sensor needs to be preheated, it takes about 30 seconds to complete the hydrogen concentration detection. During this process, the vehicle cannot be powered on at high voltage to prevent safety accidents such as hydrogen leakage and explosion during the power-on process. Through the control strategy, the vehicle controller can perform the high-voltage process after receiving the completion of the fuel cell self-test.

The whole vehicle can drive smoothly after 35 seconds, because the fuel cell vehicle is equipped with a power battery with corresponding power. Through a large number of experimental data and analysis guidelines, it is concluded that under different conditions of the power battery soc, the fuel cell outputs different powers to meet the requirements. The vehicle runs stably and increases the cruising range of the vehicle.

As shown in Fig. 2, the fuel cell stack start switch in the present invention adopts the conspicuous "H ₂ " on the front of the switch, and uses a lock without reset to prevent accidental closing. After pressing this switch, the vehicle controller receives a high The level can communicate with the fuel cell system, and execute the fuel cell work strategy to make the fuel cell intervene in the vehicle operation.

The invention can effectively protect the safety performance of the whole vehicle from the start to the working process of the fuel cell system, and at the same time reduce the energy consumption rate of the fuel cell during the working process, and it is safer to control the driver's active driving behavior.

Claims (1)

1. A fuel cell control method for passenger car, in order to realize the uninterrupted parallel coupling work of fuel cell and pure electric battery, it is characterized in that, comprises the following steps: 1) When the vehicle starts, the on-board VCU starts to power on and sends a ready signal; 2) The on-board VCU receives the stack start command that the fuel cell stack switch is turned on; 3) The vehicle-mounted VCU obtains the SOC value of the current power battery, and judges whether it is not greater than the first threshold a, if so, issue an FC ON command, and go to step 4), if not, make the fuel cell in a shutdown state; 4) After the self-check, the on-board FCU issues a command to allow loading power, and compares the SOC value with the second threshold b, specifically: 41) When b<SOC≤a, the vehicle-mounted VCU sends the first target power x to the FCU, and the FCU responds and proceeds to step 5); 42) When SOC≤b, the vehicle-mounted VCU sends the second target power y to the FCU, and the FCU responds and proceeds to step 7); If the on-board FCU self-inspection finds a fault, the on-board VCU receives the fault alarm information of the FCU and handles it according to the fault level; 5) Compare the SOC value with the third threshold value c, when a<SOC≤c, the vehicle-mounted VCU sends the third target power z to the FCU, and the FCU responds to step 6), otherwise, return to step 4); 6) When SOC≥c, the vehicle-mounted VCU issues an FC OFF command, the FCU responds to shutdown, and the fuel cell is in a shutdown state; 7) Comparing the SOC value with the fourth threshold d, when SOC≥d, the vehicle-mounted VCU sends the first target power x to the FCU, and the FCU responds to step 5), otherwise, return to step 42); The relationship between the first threshold a, the second threshold b, the third threshold c and the fourth threshold d is b<d<a<c, the first threshold a is 86%, and the second threshold b is 60%, the third threshold c is 90%, and the fourth threshold d is 65%; The magnitude relationship between the first target power x, the second target power y and the third target power z is z<x<y, the value of the first target power x is 10kW, and the value of the second target power y is 10kW. is 30kW, and the third target power z is 3kW; The front of the fuel cell stack switch is provided with the word H ₂ and an anti-reset mechanism.

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