JP6779562B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device used in a vehicle equipped with an electric negative pressure pump.

Vehicles such as automobiles are equipped with, for example, a hydraulic braking device. When the brake pedal is stepped on by the driver, the force (stepping force) input to the brake pedal is amplified (boost) by the negative pressure of the brake booster. Then, the amplified force is transmitted from the brake booster to the master cylinder. In the master cylinder, hydraulic pressure is generated according to the force input from the brake booster. The hydraulic pressure of the master cylinder is transmitted to the wheel cylinders provided on each wheel, and the hydraulic pressure of each wheel cylinder applies a braking force from each brake to the wheels.

In a vehicle using a gasoline engine as a driving source for traveling, the negative pressure generated in the intake pipe of the engine (intake pipe negative pressure) is used as the negative pressure of the brake booster. On the other hand, in electric vehicles that use a motor as a driving source for driving, hybrid vehicles in which the engine does not always operate, and vehicles equipped with a diesel engine or gasoline direct injection engine, which has a lower negative pressure in the intake pipe than a gasoline engine, the engine An electric negative pressure pump is installed because the negative pressure of the intake pipe is not generated or the negative pressure of the brake booster is insufficient.

FIG. 4 is a diagram showing the time change of the negative pressure of the brake booster and the state of the electric negative pressure pump.

When the brake operation is performed by depressing the brake pedal and the negative pressure of the brake booster is used to amplify the pedaling force, the negative pressure of the brake booster decreases. Vehicles equipped with an electric negative pressure pump are provided with a negative pressure sensor that detects the negative pressure K of the brake booster. For example, when the negative pressure K detected by the negative pressure sensor drops to the operating threshold value K _ON , the electric negative pressure pump is driven. The operation of the electric negative pressure pump raises the negative pressure K of the brake booster. Then, when the negative pressure K detected by the negative pressure sensor rises to the stop threshold value K _OFF , the operation (drive) of the electric negative pressure pump is stopped.

For example, if the electric negative pressure pump does not operate well due to a failure, the negative pressure K of the brake booster drops to the operating threshold value K _ON , and even if the electric negative pressure pump is driven, the negative pressure K does not operate well. It continues to fall below the value K _ON . When the negative pressure K drops to the warning threshold K _W, due lighting of the warning lamp, the failure of the brake system including an electric negative pressure pump (abnormal) is alerted.

Japanese Unexamined Patent Publication No. 1-178070

However, when the negative pressure K drops significantly due to the brake operation even though the brake system has not failed, or when the difference between the operating threshold value K _ON and the warning threshold value K _W is small. When the brake is operated from a state where the negative pressure K is close to the operating threshold value K _ON , the negative pressure K may drop beyond the warning threshold value K _W, and a failure of the brake system may be erroneously warned. If the warning threshold value K _W is lowered in order to suppress this false warning, it will be delayed to notify the user of the occurrence of the failure when the brake system has a failure, and there is a risk of insufficient braking force. is there.

An object of the present invention is to provide a vehicle control device capable of suppressing an erroneous warning while being able to warn the occurrence of an abnormality at an early stage.

In order to achieve the above object, the vehicle control device according to the present invention is a control device used for a vehicle provided with a brake booster and an electric negative pressure pump for supplying negative pressure to the brake booster, and is a control device of the brake booster. When the negative pressure detecting means for detecting the negative pressure and the negative pressure detected by the negative pressure detecting means drop to a predetermined operating threshold value, the electric negative pressure pump is operated and detected by the negative pressure detecting means. When the negative pressure rises to a predetermined stop threshold value, the pump control means for stopping the electric negative pressure pump and the negative pressure detected by the negative pressure detecting means are below the warning threshold value lower than the operation threshold value. It includes a warning output means for outputting a warning of the occurrence of an abnormality when the lowered state is held for a predetermined time.

According to this configuration, when the negative pressure of the brake booster is used to amplify the pedaling force by the brake operation of depressing the brake pedal, the negative pressure of the brake booster is reduced. When the negative pressure of the brake booster is detected and the detected negative pressure drops to a predetermined operating threshold value, the electric negative pressure pump operates. When the negative pressure of the brake booster is restored to a predetermined stop threshold value by the operation of the electric negative pressure pump, the electric negative pressure pump is stopped. Even if the negative pressure of the brake booster falls below the operating threshold value and drops to the warning threshold value, the warning of the occurrence of an abnormality is not immediately output, and the warning is that the negative pressure of the brake booster is below the warning threshold value. It is output when the lowered state is held for a predetermined time.

Since the negative pressure of the brake booster drops significantly due to the brake operation, even if the negative pressure drops below the warning threshold, if there is no abnormality in the brake system including the electric negative pressure pump, the brake booster is within the specified time. Negative pressure exceeds the warning threshold. In addition, even if the negative pressure of the brake booster drops below the warning threshold value due to the operation of the brake from a state close to the operation threshold value, if there is no abnormality in the electric negative pressure pump, etc., the specified time The negative pressure of the brake booster exceeds the warning threshold. Therefore, in such a case, it is possible to suppress the erroneous output of the warning of the occurrence of an abnormality.

Then, by raising the warning threshold value, an abnormality has occurred in the electric negative pressure pump, etc., and when the negative pressure of the brake booster falls below the warning threshold value, the occurrence of the abnormality occurs at an early stage. Can warn you.

Therefore, it is possible to warn the occurrence of an abnormality at an early stage and suppress an erroneous warning.

The predetermined time may be set to the continuous operation time of the electric negative pressure pump required for the negative pressure of the brake booster to rise from 0 (atmospheric pressure) to the operation threshold value, or 1 or more in the continuous operation time. It may be set by multiplying the margin.

Further, the predetermined time may be set to the warning threshold value or the continuous operation time of the electric negative pressure pump required for the negative pressure of the brake booster to rise from the current negative pressure to the operation threshold value, or the continuous operation time thereof. It may be set by multiplying the operating time by a margin of 1 or more.

The warning threshold and the predetermined time may be changed depending on the vehicle speed, the maximum voltage that can be supplied to the electric negative pressure pump, the SOC (State Of Charge) of the vehicle-mounted battery, or a combination thereof.

For example, the continuous operating time of the electric negative pressure pump required for the negative pressure of the brake booster to rise from 0 to the operating threshold value, or the continuous operating time of the electric negative pressure pump required to increase the negative pressure from the warning threshold value to the operating threshold value. When a predetermined time is set by multiplying the operating time by a margin, the margin may be changed according to the vehicle speed, the maximum voltage that can be supplied to the electric negative pressure pump, the SOC of the in-vehicle battery, or a combination thereof. ..

According to the present invention, it is possible to warn the occurrence of an abnormality at an early stage and suppress false warnings.

It is a figure which graphically shows the structure of the main part of the vehicle which adopted the control device for a vehicle which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of a pump control process. It is a figure for demonstrating the setting example of the warning threshold value and judgment reference time according to a vehicle speed. It is a figure which shows the time change of the state of the negative pressure of a brake booster, and the state of an electric negative pressure pump.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main part composition of the vehicle>
FIG. 1 is a diagram illustrating a configuration of a main part of a vehicle 1 in which a vehicle control device according to an embodiment of the present invention is adopted.

The vehicle 1 is a vehicle equipped with an electric negative pressure pump (electric vacuum pump) 3 for supplying negative pressure to the brake booster 2. For example, an electric vehicle or an engine using a motor as a driving drive source is always operated. This is a hybrid vehicle that does not have a diesel engine or a gasoline direct injection engine that has a lower negative pressure in the intake pipe than a gasoline engine.

In the vehicle 1, when the brake pedal 4 arranged in front of the driver's seat is depressed, the pedaling force input to the brake pedal 4 is transmitted to the brake booster 2. The pedaling force transmitted to the brake booster 2 is amplified (boost) by the negative pressure of the brake booster 2 and input from the brake booster 2 to the brake master cylinder 5. In the brake master cylinder 5, hydraulic pressure is generated according to the force input from the brake booster 2. The generated hydraulic pressure of the brake master cylinder 5 is transmitted to the brake actuator (not shown). This hydraulic pressure is distributed to the wheel cylinders of brakes (not shown) provided on each wheel by the function of the brake actuator, and the distributed hydraulic pressure applies braking force to the wheels from each brake.

Drive power is supplied to the electric negative pressure pump 3 from the battery 6. The battery 6 is, for example, an in-vehicle battery that outputs a DC voltage of 12 V. A relay 7 for switching the supply / stop of the drive power to the electric negative pressure pump 3 is interposed on the power supply path from the battery 6 to the electric negative pressure pump 3.

The vehicle 1 is provided with a plurality of ECUs (Electronic Control Units) having a configuration including a CPU, a ROM, a RAM, and the like. The plurality of ECUs include an ECU 8 for brake control. The plurality of ECUs are connected so that bidirectional communication can be performed by a CAN (Controller Area Network) communication protocol.

A negative pressure sensor 9, an atmospheric pressure sensor 10, a stop lamp switch 11, and the like are connected to the ECU 8. The negative pressure sensor 9 outputs a detection signal according to the pressure (absolute pressure) of the brake booster 2. The atmospheric pressure sensor 10 outputs a detection signal corresponding to the atmospheric pressure. The stop lamp switch 11 outputs an on signal when the brake pedal 4 is depressed (a state in which the brake operation is performed), and a state in which the brake pedal 4 is not depressed (a state in which the brake operation is released). It is a switch that outputs an off signal with.

The ECU 8 controls the on / off of the relay 7 based on the information detected from the detection signals of various sensors and / or various information input from other ECUs. Further, the ECU 8 controls, for example, a brake actuator or the like, and controls the braking force applied to the wheels from each brake so that the vehicle 1 is braked while the posture of the vehicle 1 is kept stable.

<Pump control process>
FIG. 2 is a flowchart showing the flow of the pump control process.

In the ECU 8, the negative pressure K of the brake booster 2 is detected based on the detection signal of the negative pressure sensor 9 and the detection signal of the atmospheric pressure sensor 10. That is, the ECU 8 detects the pressure (absolute pressure) of the brake booster 2 from the detection signal of the negative pressure sensor 9, and also detects the atmospheric pressure from the detection signal of the atmospheric pressure sensor 10. Then, the negative pressure (gauge pressure) K of the brake booster 2 is detected by subtracting the pressure of the brake booster 2 from the atmospheric pressure. The detection of the negative pressure K of the brake booster 2 is executed at a constant cycle while the start switch (ignition key switch) of the vehicle 1 is turned on.

Then, the ECU 8 executes the pump control process shown in FIG. 2 in order to operate and stop the electric negative pressure pump 3.

In the pump control process, negative pressure K is or less than the predetermined operating threshold K _ON is determined (step S1).

While the negative pressure K is larger than the operating threshold value K _ON (NO in step S1), each time the negative pressure K is detected, it is determined whether the negative pressure K is equal to or less than the operating threshold value K _ON. .. Further, while the negative pressure K is larger than the operating threshold value K _ON , the relay 7 is turned off and the electric negative pressure pump 3 is stopped.

When the brake pedal 4 is stepped on and the negative pressure K of the brake booster 2 is used to amplify the pedaling force, the negative pressure K of the brake booster 2 decreases. When the negative pressure K drops below the operating threshold value K _ON (YES in step S1), the relay 7 is turned on and the electric negative pressure pump 3 is driven (step S2). When the electric negative pressure pump 3 operates, the negative pressure generated by the electric negative pressure pump 3 is supplied (transmitted) to the brake booster 2, and the negative pressure K of the brake booster 2 rises.

While the electric negative pressure pump 3 is operating, it is determined whether or not the negative pressure K has risen to a predetermined stop threshold value K _OFF or higher (step S3). The stop threshold value K _OFF is set to a value (larger value) higher than the operation threshold value K _ON .

When the negative pressure K of the brake booster 2 rises above the stop threshold value K _OFF (YES in step S3), the relay 7 is turned off and the electric negative pressure pump 3 is stopped (step S4). Then, the pump control process is completed.

When the negative pressure K is less than the stop threshold value K _OFF (NO in step S3), it is determined whether or not the negative pressure K is equal to or less than the warning threshold value K _W (step S5). The warning threshold value K _W is set to a value lower (smaller value) than the operation threshold value K _ON . Specifically, the warning threshold value K _W is the negative of the brake booster 2 consumed when the depressing of the brake pedal 4 is released after the brake pedal 4 is depressed to the maximum with respect to the operating threshold value K _ON . The value is set as low as the pressure.

When the negative pressure K is not lowered below the warning threshold value K _W (NO in step S5), it is repeatedly determined whether or not the negative pressure K is equal to or higher than the stop threshold value K _OFF (step S3). ..

When the negative pressure K drops below the warning threshold value K _W (YES in step S5), it is determined whether or not the abnormal drop time T ₀ is stored in the RAM (step S6). The abnormal decrease time T ₀ is the time when the negative pressure K of the brake booster 2 first decreases below the warning threshold value K _W.

When the abnormal decrease time T ₀ is not stored in the RAM (NO in step S6), the current time T is stored in the RAM as the abnormal decrease time T ₀ (step S7).

When the abnormal decrease time T ₀ is stored in the RAM (YES in step S6), is the abnormal duration T-T _0, which is the elapsed time from the abnormal decrease time T ₀ to the present time, equal to or greater than the judgment reference time T _OFF ? Whether or not it is determined (step S8). The determination reference time T _OFF is, for example, a margin of 1 or more for the continuous operation time of the electric negative pressure pump 3 required for the negative pressure K of the brake booster 2 to rise from 0 (atmospheric pressure) to the operation threshold value K _ON. It is set by multiplying by.

When the abnormal duration T-T ₀ is less than the judgment reference time T- _OFF (NO in step S8), the process returns to step S3, and it is determined again whether or not the negative pressure K is equal to or higher than the stop threshold value K- _OFF. Will be done.

When the abnormal duration TT ₀ reaches the judgment reference time T _OFF while the negative pressure K of the brake booster 2 is lowered to the warning threshold value K _W or less (YES in step S8), the electric negative pressure pump 3 It is substantially determined that an abnormality (failure) has occurred in the brake system including the negative pressure sensor 9 and the like. In this case, a warning of the occurrence of an abnormality in the brake system is output by lighting the warning lamp provided in the meter unit of the vehicle 1 (step S9), and the pump control process is completed. At this time, the operation of the electric negative pressure pump 3 may be stopped.

<Effect>
As described above, when the negative pressure K of the brake booster 2 is used to amplify the pedaling force by the brake operation of depressing the brake pedal 4, the negative pressure K of the brake booster 2 decreases. When the negative pressure K of the brake booster 2 is detected and the detected negative pressure K drops to a predetermined operating threshold value K _ON , the electric negative pressure pump 3 operates. When the negative pressure K of the brake booster 2 is restored to the predetermined stop threshold value K _OFF by the operation of the electric negative pressure pump 3, the electric negative pressure pump 3 is stopped. Even if the negative pressure K of the brake booster 2 falls below the operating threshold value K _ON and drops to the warning threshold value K _W , the warning of the occurrence of an abnormality is not immediately output, and the warning is the negative pressure of the brake booster 2. This is output when the state in which K has dropped below the warning threshold value K _W is held for the judgment reference time T _OFF .

Since the negative pressure K of the brake booster 2 drops significantly due to the brake operation, even if the negative pressure K drops below the warning threshold value K _W , if there is no abnormality in the brake system including the electric negative pressure pump 3. The negative pressure K of the brake booster 2 exceeds the warning threshold value K _W within the judgment reference time T _OFF . Further, even when the negative pressure K of the brake booster 2 drops below the warning threshold value K _W due to the operation of the brake from a state close to the operating threshold value K _ON , the electric negative pressure pump 3 or the like If there is no abnormality, the negative pressure K of the brake booster 2 exceeds the warning threshold value K _W within the judgment reference time T _OFF . Therefore, in such a case, it is possible to suppress the erroneous output of the warning of the occurrence of an abnormality.

Then, by raising the warning threshold K _W, for such abnormal electric negative pressure pump 3 is generated, when the negative pressure K of the brake booster 2 is below the warning threshold K _W, its The occurrence of an abnormality can be warned at an early stage.

Therefore, it is possible to warn the occurrence of an abnormality at an early stage and suppress an erroneous warning.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, the warning threshold value K _W and the determination reference time T _OFF may be changed according to the vehicle speed of the vehicle 1. In this case, it is preferable that the higher the vehicle speed, the higher the warning threshold value K _W is set, and the shorter the determination reference time T _OFF is set.

As an example, as shown in FIG. 3, when the vehicle speed V of the vehicle _{1 is} equal to or less than the predetermined vehicle speed V ₁ , the warning threshold value K _W and the judgment reference time T _OFF are the warning threshold values K for low vehicle speeds, respectively. is set to _W1 and the reference time _{T OFF1,} when the vehicle speed V is greater than a predetermined vehicle speed _{V 1} was, warning threshold _{K W} and the reference time _{T OFF} is a high speed, respectively warning threshold _{K W2} and criteria The time T _{OFF 2} may be set.

In this case, the warning threshold value K _W2 for high vehicle speed is preferably a value higher than the warning threshold value K _W1 for low vehicle speed. Further, the reference time T _OFF2 for high speed is preferably shorter than the reference time T _OFF1 for low speed. As a result, it is possible to further suppress the erroneous output of the warning of the occurrence of an abnormality when the vehicle 1 is traveling at a low speed, and when the vehicle 1 is traveling at a high speed, the occurrence of an abnormality and the brake booster 2 are compared with those during the low speed traveling. It is possible to warn at an earlier stage of the lack of braking effect due to the low negative pressure of.

Further, three or more vehicle speed ranges V _n <V ≤ V _{n + 1} (N = 1, 2, 3, ...) Are set, and a warning threshold value is set for each vehicle speed range V _n <V ≤ V _{n + 1.} The K _W and the determination reference time TOFF may be changed. In this case, the warning threshold value K _W is set to a high value as the vehicle speed range Vn <V ≦ Vn + 1 on the high vehicle speed side, and the judgment reference time T _OFF is set to a short time. The threshold value K _W is set to a high value, and the judgment reference time T _OFF is set to a short time.

The judgment reference time T _OFF is set to the continuous operation time of the electric negative pressure pump 3 required for the negative pressure K of the brake booster 2 to rise from the warning threshold value K _W or the current negative pressure to the operation threshold value K _ON. It may be set by multiplying the continuous operation time by a margin of 1 or more.

The warning threshold value K _W and the determination reference time T _OFF may be changed according to the vehicle speed, the maximum voltage that can be supplied to the electric negative pressure pump 3, the SOC (State Of Charge) of the vehicle-mounted battery, or a combination thereof. ..

Further, when the value of the operating threshold value K _ON is changed according to the vehicle speed or the SOC, the warning threshold value K _W may be changed according to the value of the operating threshold value K _ON . By doing so, the value of "operation threshold value K _ON -warning threshold value K _W " can be kept constant so that the frequency does not change, or "operation threshold value K _ON -warning threshold value" can be prevented. K _W "or the value from the warning threshold K _W by reducing in response to increase of the operating threshold K _oN to align the arrival time at the time of recovery to the working threshold K _oN the" operation By expanding the value of "threshold value K _ON -warning threshold value K _W " in response to an increase in the operating threshold value K _ON , a warning may be output at an early stage when the vehicle speed is high.

For example, the continuous operating time or warning threshold K _{W of the} electric negative pressure pump 3 required for the negative pressure K of the brake booster 2 to rise from 0 to the operating threshold K _ON, or the operating threshold from the current negative pressure. When the judgment reference time T _OFF is set by multiplying the continuous operation time of the electric negative pressure pump 3 required to rise to K _ON by the margin, the margin can be supplied to the vehicle speed and the electric negative pressure pump 3. It may be changed depending on the maximum voltage or the SOC of the vehicle-mounted battery or a combination thereof.

Further, in the above-described configuration, the ECU 8 is connected to a negative pressure sensor 9 that outputs a detection signal corresponding to the pressure (absolute pressure) of the brake booster 2 and an atmospheric pressure sensor 10 that outputs a detection signal corresponding to the atmospheric pressure. , The pressure (absolute pressure) of the brake booster 2 detected from the detection signal of the negative pressure sensor 9 is subtracted from the atmospheric pressure detected from the detection signal of the atmospheric pressure sensor 10 by the ECU 8, so that the negative pressure of the brake booster 2 is negative. Pressure (gauge pressure) is detected. When the negative pressure sensor 9 is configured to output a detection signal according to the gauge pressure of the brake booster 2, the atmospheric pressure sensor 10 is omitted, and the negative pressure of the brake booster 2 is detected from the detection signal of the negative pressure sensor 9. You may.

In addition, various design changes can be made within the scope of the matters described in the claims.

1 Vehicle 2 Brake booster 3 Electric negative pressure pump 8 ECU (vehicle control device, negative pressure detecting means, pump control means, warning output means)
9 Negative pressure sensor 10 Atmospheric pressure sensor

Claims (1)

A control device used in a vehicle equipped with a brake booster and an electric negative pressure pump for supplying negative pressure to the brake booster.
Negative pressure detecting means for detecting the negative pressure of the brake booster and
When the negative pressure detected by the negative pressure detecting means drops to a predetermined operating threshold value, the electric negative pressure pump is operated, and the negative pressure detected by the negative pressure detecting means stops at a predetermined stop. A pump control means for stopping the electric negative pressure pump when the value rises to a value, and
A warning output means that outputs a warning of the occurrence of an abnormality when a state in which the negative pressure detected by the negative pressure detecting means drops below the warning threshold value lower than the operating threshold value is held for a predetermined time. only including,
The operating threshold value is set according to the vehicle speed of the vehicle, the maximum voltage that can be supplied to the electric negative pressure pump, the SOC of the battery mounted on the vehicle, or a combination thereof, and the operating threshold value is set to the operating threshold value. A vehicle control device in which the warning threshold value is set accordingly .

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