CN110254434B - Control method for preventing hybrid vehicle from sliding down slope during idle charging - Google Patents

Abstract

The invention discloses a control method for idling charging of a hybrid vehicle to prevent slippage. After detecting that the vehicle enters the idling state, a vehicle controller firstly detects whether the idling charging entry conditions are satisfied, including: 1. the vehicle is stationary; 2. the power battery is charged The SOC value of the electrical state is lower than the set maximum value; 3. The gearbox is in P/N gear or the brake pedal is depressed; 4. The engine running state is allowed; 5. The transmission chain is open; : Step 1: When the ESP signal is valid and the vehicle is stationary, the ESP sends the vehicle longitudinal acceleration coefficient signal to the vehicle controller, and the vehicle controller calculates the ramp angle θ≈57.3*a, where a is the vehicle longitudinal acceleration coefficient; Step 2: Ramp Whether the angle is less than or equal to the calibration value, if so, allow idle charging, if not, allow it. The present invention judges whether the vehicle is allowed to enter the idle charging mode according to the angle of the ramp where the vehicle is located, and solves the problem of slope slippage in the process of switching the hybrid vehicle from the idle charging mode to the hybrid mode.

Description

Control method for anti-slip slope of hybrid electric vehicle idling charging

technical field

The invention relates to a driving control method for a hybrid electric vehicle, in particular to a control method for idling charging and anti-slope of the hybrid electric vehicle.

Background technique

The hybrid electric vehicle of the prior art can adjust the working point of the engine by charging the generator at an idle speed through the engine, so as to achieve the purpose of improving the efficiency of the engine and reducing the fuel consumption. The control method in the prior art is: the system detects the state of charge (SOC) of the battery, the depth of pedal depression, the engine running state and the transmission chain state to determine the current vehicle operating condition, and then sends a command to enter or exit idle charging. Referring to Figure 1, the specific logic for judging whether to allow idling charging is: judging whether the vehicle is in a stationary state; whether the brake pedal opening is greater than the limit for entering idling charging; whether the transmission chain state is open; whether the SOC of the battery is Satisfaction; whether the engine running state is allowed. When all of the above conditions are met, the vehicle is allowed to enter idle charging, on the contrary, when the vehicle cannot meet any one of the conditions, the vehicle is prohibited from entering idle charging.

The above idle charging control method has certain limitations. For example, when the vehicle is on a road with a slope angle and the above conditions are met, the controller controls the vehicle to enter the idle charging mode. After the charging is completed, the power mode of the vehicle will be idle charging. The mode is switched to the hybrid mode. At this time, the engine gearbox needs to open the clutch, return to the C gear, and the motor is in the low gear (L gear). When the motor has not been successfully hung in the low gear, there is a phenomenon that the power system is disconnected. Cause the vehicle to lose power. This process takes about 2 seconds, during which a landslide may occur.

Since the control logic of the prior art lacks the limitation of calculating the slope angle and judging whether the slope angle allows the vehicle to enter the idle charging mode, when the slope angle is too large, the vehicle will roll off the slope. In order to solve this problem, some vehicles make up for the defects of vehicle control logic by installing ramp angle detection equipment, but the installation of ramp angle detection equipment not only increases the cost, but also has certain limitations on the hardware and software configuration of related components on the vehicle. Require.

The Chinese invention patent No. ZL201110338079.5 discloses a control method and system device for automatic idling start and stop of an engine, by detecting signals indicating the voltage of the energy storage system, vehicle speed, engine speed, rolling state, air pressure of the air brake system, etc. , and selectively start and stop the engine based on the above-mentioned signals. The patent uses the prohibition of engine shutdown when the slope is stationary to maintain the vacuum of the braking device, thereby preventing the risk of slope slippage caused by insufficient braking force, but it cannot avoid the slope slope problem that may be caused in the process of power switching.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a control method for idling charging and anti-slope of a hybrid vehicle, which can judge whether the vehicle is allowed to enter the idling charging mode according to the slope angle of the slope where the vehicle is located, thereby effectively solving the problem of the hybrid vehicle in the prior art. Rollover problem during switching from idle charging mode to hybrid mode.

The present invention is realized in this way:

A control method for idling charging of a hybrid vehicle to prevent slippage. After detecting that the vehicle enters an idling state, a vehicle controller firstly detects whether the idling charging entry conditions are satisfied. The idling charging entry conditions include: 1. The vehicle is stationary; 2. The power battery The SOC value of the state of charge is lower than the set maximum value; 3. The gearbox is in P/N gear or the brake pedal is depressed, and the pedal opening is greater than the set limit; 4. The engine running state is allowed; 5. The transmission chain is open;

When all the above conditions are met, the judgment of the slope angle condition is carried out;

The said ramp angle condition judgment includes the following steps:

Step 1: When the ESP signal is valid and the vehicle is stationary, the ESP sends the vehicle longitudinal acceleration coefficient signal to the vehicle controller, and the vehicle controller calculates the ramp angle θ according to the vehicle longitudinal acceleration coefficient signal. The calculation formula is as follows:

θ≈57.3*a

Among them, a is the vehicle longitudinal acceleration coefficient, a is calculated by ESP and sent to the vehicle controller;

Step 2: ESP judges whether the slope angle θ is less than or equal to the calibration value, if so, the vehicle is allowed to enter the idle charging mode, if not, the vehicle is not allowed to enter the idle charging mode.

In the step 1, when the ESP signal is invalid, the slope angle θ is 0° by default.

The invalid ESP signal includes: (1) the ESP judges that the longitudinal acceleration sensor is faulty; (2) the communication between the vehicle controller and the ESP is abnormal.

In the step 2, the calibration value of the ramp angle is 3°.

The present invention adds a ramp angle calculation function module on the basis of the existing idle charging function module, and uses the ramp angle of the ramp where the vehicle is located as a logical judgment condition for whether to allow the vehicle to enter idle charging. When the ramp angle is less than or equal to a limit value When , the vehicle is allowed to enter the idle charging mode on the slope, and when the slope angle is greater than the limit value, the vehicle is prohibited from entering the idle charging mode, which solves the problem of slipping when the hybrid vehicle is switched from the idle charging mode to the hybrid mode.

Description of drawings

FIG. 1 is a logic diagram of idle charging judgment of a hybrid electric vehicle in the prior art.

FIG. 2 is a flow chart of a control method for idling charging of a hybrid vehicle to prevent slippage according to the present invention;

3 is a schematic diagram of the control method for idling charging of a hybrid vehicle to prevent slippage according to the present invention;

FIG. 4 is a connection diagram of a hybrid vehicle during idling charging.

In the picture, 1 clutch, 2 engine end C gear, 3 charging gear, 4 motor gear, 5 engine, 6 motor, 7 gearbox.

Detailed ways

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

Please refer to FIG. 2 , a control method for idling charging of a hybrid vehicle to prevent slippage. After detecting the driver's idling charging intention, that is, after the vehicle enters the idling state, the vehicle controller needs to first detect whether the idling charging entry conditions are satisfied. , the idle charging entry conditions include: 1. The vehicle is stationary; 2. The power battery SOC (State of Charge, meaning battery state of charge, also known as the remaining power) value is lower than the set maximum value; 3. The gearbox is in P/N gear or the brake pedal is pressed, and the pedal opening is greater than the set limit; 4. The engine running state is allowed; 5. The transmission chain is opened.

When all of the above conditions are satisfied, the judgment of the slope angle condition is performed. The said ramp angle condition judgment includes the following steps:

Step 1: When the ESP (Electronic Stability Program) signal is valid and the vehicle is stationary, the ESP sends the vehicle longitudinal acceleration coefficient signal to the vehicle controller, and the vehicle controller calculates the ramp angle θ according to the vehicle longitudinal acceleration coefficient signal ,Calculated as follows:

θ≈57.3*a

Among them, a is the vehicle longitudinal acceleration coefficient, and the value of a is calculated by the ESP and sent to the vehicle controller through the vehicle CAN communication.

When the ESP signal is invalid, that is, when the ESP judges that the longitudinal acceleration sensor is faulty or the CAN communication between the ESP and the vehicle controller is abnormal, the slope angle θ is 0° by default.

车辆加速度为a*g，

因此，

计算得到θ≈57.3*a。Please refer to Figure 3, when the ramp angle θ is small, sinθ≈arc length c, the arc length

The vehicle acceleration is a*g,

therefore,

It is calculated that θ≈57.3*a.

Among them, a is the longitudinal acceleration coefficient of the vehicle, and g is the gravitational acceleration.

Step 2: ESP judges whether the slope angle θ is less than or equal to the calibration value, if so, the vehicle is allowed to enter the idle charging mode, if not, the vehicle is not allowed to enter the idle charging mode.

Preferably, the calibration value of the ramp angle is 3°, that is, when the ramp angle θ<3°, the vehicle enters the idle charging mode; when the ramp angle θ≥3°, the vehicle does not enter the idle charging mode, which avoids Switching of power modes. Among them, the calibration value of 3° is the empirical value. When the slope angle θ < 3°, the response time of the vehicle to slide the slope is much lower than that of the power switching mode, which can effectively avoid the occurrence of the slope. The calibration value can also be adjusted appropriately according to different models.

Please refer to FIG. 4 , when the vehicle is idling charging, the engine-side C-speed gear 2 and the charging gear 3 mesh with the motor gear 4 through the closed clutch 1 to complete the connection between the engine 5 and the motor 6 and realize the idling charging function; when After the charging is completed, the gearbox 7 returns to the C gear, and the motor 6 is in the L/H gear to complete the switching of the power mode.

Example: The actual test value of the vehicle longitudinal acceleration coefficient a under different ramp angles θ is obtained through testing, as shown in Table 1.

Table 1: Values of vehicle longitudinal acceleration coefficient a under different ramp angles θ

Ramp angle θ (actual measurement) (°) Longitudinal acceleration coefficient a (actual test) Example 1 0.5 0.0087 Example 2 1 0.0175 Example 3 1.5 0.0262 Example 4 2 0.0349 Example 5 2.5 0.0436 Example 6 3 0.0523 Example 7 3.5 0.061 Example 8 4 0.0698

计算可得θ≈57.3*a。According to sinθ≈arc length,

It can be calculated that θ≈57.3*a.

Therefore, according to the formula θ≈57.3*a, the slope calculation angles of the 8 embodiments in Table 1 are calculated, and Table 2 is obtained:

Table 2: Calculated value of ramp angle and its error (when the calibration value is 3°)

It can be seen from Table 2 that when the longitudinal acceleration coefficient a is 0.0087 through monitoring, θ≈57.3*a=0.4985, the slope calculation angle is 0.4985° and is less than 3° of the calibration value, allowing the vehicle to enter the idle charging mode on the ramp; The actual slope angle corresponding to the acceleration coefficient a is 0.5°, the relative error is -0.00298, the error range is small, and the control is precise.

When the longitudinal acceleration coefficient a is 0.061 through monitoring, θ≈57.3*a=3.495, the slope calculation angle is 3.495° and is 3° greater than the calibration value, and the vehicle is not allowed to enter the idle charging mode on the ramp; the longitudinal acceleration coefficient a The corresponding actual ramp angle is 3.5°, the relative error is -0.00134, the error range is small, and the control is precise.

The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (3)

1. A control method for preventing a hybrid vehicle from slipping off a slope during idle charging is characterized by comprising the following steps: after detecting that the vehicle enters an idle state, the vehicle controller firstly detects whether an idle charge entry condition is met, wherein the idle charge entry condition comprises: 1. the vehicle is stationary; 2. the SOC value of the power battery is lower than a set maximum value; 3. the gearbox is in a P/N gear or a brake pedal is stepped on, and the opening degree of the pedal is larger than a set limit value; 4. the engine running state allows; 5. opening a transmission chain;

when all the conditions are met, judging the angle condition of the ramp; the judgment of the ramp angle condition comprises the following steps:

step 1: when the ESP signal is active and the vehicle is stationary, the ESP sends a vehicle longitudinal acceleration coefficient signal to the vehicle controller, which calculates the ramp angle θ from the vehicle longitudinal acceleration coefficient signal, as follows:

θ≈57.3*a

wherein a is a vehicle longitudinal acceleration coefficient, and a is calculated by the ESP and is sent to a vehicle controller;

step 2: the ESP judges whether the ramp angle theta is smaller than or equal to a calibration value, if so, the vehicle is allowed to enter an idle charging mode, and if not, the vehicle is not allowed to enter the idle charging mode;

in step 1 described, when the ESP signal is inactive, the ramp angle θ defaults to 0 °.

2. The idle charging hill drop prevention control method of a hybrid vehicle as set forth in claim 1, characterized in that: the ESP signal invalidation includes: (1) the ESP judges that the longitudinal acceleration sensor has a fault; (2) the vehicle controller communicates abnormally with the ESP.

3. The idle charging hill drop prevention control method of a hybrid vehicle as set forth in claim 1, characterized in that: in step 2, the ramp angle is calibrated to 3 °.

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