JPH08322104A - Braking system of electric automobile - Google Patents

Abstract

PURPOSE: To prevent increase and decrease in braking force caused by the dispersion and the time change of brake lamp switches and a hydraulic sensor, to improve brake feeling and to enhance fault detecting performance. CONSTITUTION: Two brake lamp switches 20 (1) and 20 (2) are provided. The mode is changed to a regeneration priority mode when the brake lamp switches 20 (1) and 20 (1) are turned on. The outputs of a hydraulic sensor 26 and the brake lamp switches 20 (1) and 20 (2) are compared each other. Thus, the presence or absence of the fault in these parts is judged. When the fault is detected, the mode is changed to a regeneration inhibition mode. In the changing conditions to the regeneration precedence mode, the conditions related to the output value of the hydraulic sensor 26 are not included. Therefore, even when the high fault occurs in the hydraulic sensor 26, excellent feeling is obtained. Since the fault is detected by the mutual comparison of the outputs, the faulty part and the fault mode can be specified. One or more hydraulic switches can be provided at the same location as the hydraulic sensor 26. In place of the hydraulic sensor 26, the hydraulic switch can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking device which is mounted on an electric vehicle and realizes a required braking force by a fluid pressure braking force by an incompressible fluid and a regenerative braking force by regenerating traveling energy.

[0002]

2. Description of the Related Art As a means for braking a vehicle, fluid pressure braking using an incompressible fluid such as braking oil is widely used. In an electric vehicle equipped with a motor as a driving means of a vehicle, regenerative braking for braking the vehicle by regeneration of running energy can also be used. Regenerative braking is a braking method in which a portion of the running energy of the vehicle is regenerated as braking energy into a vehicle-mounted battery or the like, and therefore has the advantage that it can contribute to improving the energy efficiency of the vehicle rather than fluid pressure braking. Therefore, in an electric vehicle that can use both fluid pressure braking and regenerative braking, the energy efficiency of the vehicle can be improved by preferentially using the regenerative braking over the fluid pressure braking, and the onboard battery can be used. The frequency of charging with external power or the like can be suppressed.

When the regenerative braking is preferentially used over the fluid pressure braking, it is necessary to consider the realization of the required braking force and the optimization of the braking force distribution between the driving wheels and the driven wheels. In other words, the regenerative braking force can act only on the drive wheels due to the nature of regenerating energy by the vehicle traveling motor, whereas the fluid pressure braking force can act on both the drive wheels and the driven wheels, so that the brake pedal If the required braking force given as the fluid pressure in the brake master cylinder (M / C) is applied as it is as the fluid pressure braking force while the regenerative braking force is also generated, the braking force exceeding the required braking force will be generated. And the braking force distribution between the driving wheel and the driven wheel may be disrupted. In order to prevent such a problem, the applicant of the present application has already proposed a technique in which the regenerative braking force is preferentially used with respect to the fluid pressure braking force and the action of the fluid pressure braking force is delayed by an amount corresponding to the regenerative braking force. Kaihei 5-1
76407, etc.). FIG. 17 shows an example of the configuration of a system that can be realized by using the previously proposed technique.

In this figure, a motor 1 for running a vehicle is shown.
An AC motor is used as 0. The drive power of the motor 10 is given from the vehicle-mounted battery 14 via the inverter 12. The inverter 12 converts the DC power discharged from the battery 14 into AC power under the control of the ECU 16 and supplies the AC power to the motor 10. The output shaft of the motor 10 is connected to drive wheels (not shown) via the transmission 18 and the like, and therefore is requested by the vehicle operator by controlling the power conversion operation by the inverter 12 according to the amount of depression of the accelerator pedal. Acceleration can be realized. Therefore, the ECU 16 determines a torque command for the motor 10 according to the depression amount of an accelerator pedal (not shown), and the inverter 1 according to the obtained torque command.
2 controls the power conversion operation.

Regenerative braking can be realized by controlling the power conversion operation by the inverter 12 as in the case of vehicle acceleration. That is, when the brake lamp switch 20 detects the depression of the brake pedal 22, the ECU 1
6 detects the hydraulic pressure (M / C pressure) in the M / C 24 with respect to the oil passage on the drive wheel side by using the hydraulic pressure sensor 26, and the traveling motor 10 obtains the regenerative torque corresponding to the detected M / C pressure. The inverter 12 controls the power conversion operation. As a result, the regenerative braking force according to the M / C pressure, and eventually the braking force required by the vehicle operator, can be applied to the brake wheel 28a on the drive wheel side.

On the other hand, in order to accurately realize the required braking force and optimize the braking force distribution between the driving wheels and the driven wheels, it is necessary to limit or cut off the hydraulic braking force according to the regenerative braking force (regenerative torque). There is. Therefore, from the M / C 24 to the drive wheel side and the driven wheel side wheel cylinders (W / C) 30a, 30
Pressure reducing valves 32a and 32b are provided on the oil passage leading to b. The pressure reducing valves 32a and 32b correspond to the oil pressures in the corresponding hydraulic chambers of the M / C 24 and the corresponding W / Cs 30a and 30b.
Transmission of hydraulic pressure is interrupted until the pressure difference with the hydraulic pressure (W / C pressure) reaches a predetermined valve opening value or more, and when it exceeds the valve opening value, hydraulic pressure is transmitted while maintaining the differential pressure at that time. Has the function to start. Therefore, the M / C pressure is low (that is, the brake pedal 22 is shallowly depressed).
Then, as a result of the hydraulic pressure being cut off by the pressure reducing valve 32a, only the regenerative braking force acts on the brake wheel 28a.
It becomes possible to regenerate all. In addition, the pressure reducing valve 32
In the state after the differential pressure before and after a reaches the valve opening value (that is, the state where the brake pedal 22 is deeply depressed), the hydraulic braking force is collected while the braking energy corresponding to the valve opening value of the pressure reducing valve 32a is collected in the battery 14. Since the braking force is applied to the brake wheel 28a, the required braking force can be reliably realized. Therefore, by appropriately setting the valve opening value of the pressure reducing valve 32a, the required braking force corresponding to the depression amount of the brake pedal 22 can be reliably and accurately realized on the drive wheel side.

Further, in this system, bypass valves 34a and 34b are provided in parallel with the pressure reducing valves 32a and 32b. The bypass valves 34a and 34b are valves that can be realized as, for example, solenoid valves.
It is turned on / off under the control of the CU 16. In the ON state, the bypass valves 34a and 34b block the hydraulic pressure transmission between the oil passages before and after the bypass valves 34a and 34b, and in the OFF state, the hydraulic pressure is allowed. Therefore, for example, when it is recognized that the M / C pressure detected by the hydraulic pressure sensor 26 has an error of a predetermined degree or more with respect to the actual M / C pressure, the bypass valves 34a, 3
If 4b is turned off, the M / C pressure will be W / C 30a, 30b.
As a result of being transmitted to the brake wheel 28a on the drive wheel side
A hydraulic braking force corresponding to the required braking force acts on the brake wheel 28b on the driven wheel side. As a result, it is possible to preferably deal with the failure of the hydraulic sensor 26. The hydraulic sensor 36 provided on the wheel cylinder 30a side has a function of detecting a failure of the hydraulic sensor 26 as one of its functions.

FIG. 18 shows the ECU 1 in this embodiment.
6 shows the flow of the operation relating to the control of the regenerative braking force and the hydraulic braking force. As shown in this figure, the ECU 16 first executes initialization processing such as energizing the solenoids of the bypass valves 34a and 34b to turn on these valves (100). As a result, M / C24 to W
/ C30a, 30b on the oil passage to the pressure reducing valve 32a, 32
b is inserted.

Thereafter, the ECU 16 determines whether the motor 10, the inverter 12, the battery 14, etc. are in a state where regenerative braking can be executed (102). For example, when it is considered that the battery 14 does not have the ability to receive the regenerative electric power when viewed from the state of charge (SOC) and voltage of the battery 14, or when the necessary regenerative torque is output based on the temperature of the motor 10 and the inverter 12. If it does not seem to be in a profitable state, the ECU 16 shifts to the regeneration prohibition mode. In other cases, the ECU 16 controls the hydraulic pressure sensors 26 and 36.
Are compared with each other (104), and based on the result, it is determined whether or not a failure has occurred in the hydraulic pressure sensor 26 (1
06). As a result, the ECU 16 shifts to the regeneration prohibition mode when it is recognized that the hydraulic pressure sensor 26 has a failure,
In other cases, the regeneration priority mode is entered.

In the regeneration priority mode, the ECU 16
First, it is determined whether or not the brake lamp switch 20 is turned on (108). Brake lamp switch 2
0 is set to turn on when the brake pedal 22 is depressed. Therefore, the brake lamp switch 20
If it is determined that the brake pedal 22 is turned on, it can be considered that the vehicle operator depresses the brake pedal 22. Therefore, the ECU 16 controls the M / C pressure detected by the hydraulic pressure sensor 26 or the hydraulic pressure sensor. The required regenerative braking force is obtained based on the differential pressure obtained by subtracting the W / C pressure on the drive wheel side detected by 36 from this M / C pressure, and the obtained regenerative braking force is realized by the motor 10 as regenerative torque. Control of the inverter 12 is executed (110).

The ECU 16 uses the brake lamp switch 2
When 0 is not on (108), the power conversion operation by the inverter 12 is controlled (112) in principle so that the regenerative torque becomes 0. That is, when it can be considered that the brake pedal 22 is not depressed by the vehicle operator, regenerative braking is not executed. However, even when the brake lamp switch 20 is not turned on, the M / C pressure detected by the hydraulic pressure sensor 26 is δ ₁ (0 <δ ₁ ).
If it is above, it can be considered that the brake pedal 22 is depressed (114), so the ECU 16 executes the above-mentioned step 110. Providing such a step 114 is because the brake lamp switch 20 is turned off,
That is, this is to appropriately deal with a situation in which a failure of the nature that the brake pedal 22 is constantly turned off regardless of whether the brake pedal 22 is depressed or not, and to reliably generate the braking force.

If it is determined in step 102 that regenerative braking cannot be executed, or if it is determined in step 106 that the hydraulic pressure sensor 26 has a failure, the ECU
16 executes the regeneration prohibition mode as described above. In this mode, the ECU 16 cuts off the power supply to the solenoid of the bypass valve 34a to turn off the bypass valve 34a (116). As a result, the M / C pressure remains W
/ C30a, the required braking force can be realized regardless of the regenerative braking ability, and regardless of whether the hydraulic sensor 26 has a failure. In this state, the ECU 16 further controls the power conversion operation by the inverter 12 so that the regenerative torque becomes 0, lights an abnormal lamp (not shown) to notify the vehicle operator of the situation, and shifts to the regeneration prohibited mode. A diagnosis indicating a thing is stored inside. ECU16
Continues the regeneration prohibition mode until the regeneration ability is restored or the failure of the hydraulic sensor 26 is resolved (118).

FIG. 19 illustrates the principle used in detecting a failure of the hydraulic sensor 26 in steps 104 and 106. The horizontal axis of this figure is the actual M / C pressure,
The vertical axis represents the output of the hydraulic pressure sensor 26.
Since the ideal output of the hydraulic pressure sensor 26 should have the characteristics shown by the alternate long and short dash line in the figure, if it is possible to detect that the actual output of the hydraulic pressure sensor 26 deviates significantly from this alternate long and short dash line, then the failure of the hydraulic pressure sensor 26 is detected. It can be detected. In step 104, it is detected using the output of the hydraulic sensor 36 on the W / C 30a side that the actual output of the hydraulic sensor 26 has largely deviated from the ideal output indicated by the alternate long and short dash line. The ideal output of the hydraulic pressure sensor 36 has a characteristic that the ideal output of the hydraulic pressure sensor 26 is shifted to the right side in the figure by the valve opening value of the pressure reducing valve 32a, as indicated by the chain double-dashed line in FIG. At this time, the error of the oil pressure sensor 36, the hysteresis of the characteristic of the pressure reducing valve 32a, the error, and the variation also affect, and the failure region of the oil pressure sensor 26 that can be detected in step 104 is two regions indicated by the diagonal lines in the figure.

[0014]

In this system, regenerative braking can be started by using the output of the M / C side oil pressure sensor even when an off failure occurs in the brake lamp switch, and W A failure of the M / C side oil pressure sensor can be detected using the output of the / C side oil pressure sensor. However, even if no failure occurs in the brake lamp switch, when a failure occurs in the M / C side oil pressure sensor, regenerative braking force begins to act, and as a result, a braking force slightly larger than the required braking force is generated. There is a problem of doing. That is, when a failure (high failure) in a mode in which the M / C side oil pressure sensor outputs a value slightly larger than the actual M / C pressure occurs due to aging or the like, the vehicle operator depresses the brake pedal. Even if it is not, the condition of the above-mentioned step 114 is satisfied, and the regenerative torque may be generated by step 110. However, when the operation of the ECU returns to steps 104 and 106 after step 100 after execution of step 100, a failure of the M / C side hydraulic sensor is detected and the mode is shifted to the regenerative prohibition mode, and the regenerative torque generated is different from that of the vehicle. Considering that it is a small value that does not affect the operation at all, it is clear that the failure as described above does not affect the operation performance. However, if a small amount of regenerative torque is generated due to a high failure of the M / C side oil pressure sensor, a feeling of strangeness is given to the vehicle operator and the feeling is deteriorated.

Further, in the above-mentioned system, hydraulic pressure sensors having linear characteristics are used as the M / C side and W / C side hydraulic pressure sensors. However, this type of sensor has a problem in that, in addition to the problem that the price thereof is high, there is a variation between individual objects, so that a relatively wide error must be tolerated as shown in FIG. Further, the pressure reducing valve interposed between the M / C side oil pressure sensor and the W / C side oil pressure sensor usually has a large hysteresis characteristic, and further has an error or variation in the characteristic. Therefore, the process of detecting the failure of the M / C side oil pressure sensor using the output of the W / C side oil pressure sensor cannot be executed very accurately.
That is, as shown in FIG. 19, it is possible to detect only a failure in a region far away from the ideal output of the M / C side oil pressure sensor.

The present invention has been made to solve the above problems, and an oil pressure sensor for detecting a malfunction of a depression sensor (for example, a brake lamp switch) for detecting whether or not a brake pedal is depressed. It is an object of the present invention to realize a braking device capable of appropriately generating a regenerative braking force irrespective of whether or not there is a failure in a hydraulic sensor or the like by detecting without using. The present invention
Further, a plurality of required braking force sensors (for example, hydraulic pressure sensors) for detecting the required braking force are provided without interposing a member such as a pressure reducing valve therebetween, and the required braking force sensor is used to output the required braking force. An object of the present invention is to make it possible to detect the failure of the required braking force sensor by detecting the failure of the sensor without being influenced by the hysteresis characteristic of the pressure reducing valve or the error or variation of the characteristic. A further object of the present invention is to detect failures of these sensors by comparing and collating outputs of the stepping sensor and the required braking force sensor, and at least partially identify the failure location and failure mode. It is an object of the present invention to realize a vehicle having higher fail-safe performance, higher failure detection performance, and a better feeling by achieving the above-mentioned object.

[0017]

In order to achieve such an object, a braking device mounted on an electric vehicle according to the first configuration of the present invention detects whether or not a brake pedal is depressed. A plurality of stepping sensors (for example, a brake lamp switch) and means for detecting the failure of the plurality of stepping sensors by mutually comparing the detection results, and when no failure is detected for any of the stepping sensors. In addition, the means for applying the required braking force to the drive wheels while distributing the fluid pressure braking force by the non-compressible fluid and the regenerative braking force by the regeneration of the traveling energy are provided.

Further, according to the second aspect of the present invention, the braking device mounted on the electric vehicle includes a plurality of required braking forces for detecting the required braking force provided by the fluid pressure corresponding to the depression amount of the brake pedal. A sensor (for example, a hydraulic sensor, a hydraulic switch, a stroke sensor) and a means for detecting the failure of the plurality of required braking force sensors by comparing the detection results with each other, and a failure of any required braking force sensor. If not detected, the braking force according to the detection result of at least one of the required braking force sensors is driven while distributing to the fluid pressure braking force due to the incompressible fluid and the regenerative braking force due to regeneration of running energy. And means for acting on the ring.

A braking device mounted on an electric vehicle according to a third aspect of the present invention includes a plurality of the above-mentioned stepping sensors and a plurality of required braking force sensors, respectively, and further compares the detection results with each other to obtain the above. A means for detecting a failure of the plurality of stepping sensors and the plurality of required braking force sensors, and a fluid pressure braking force by an incompressible fluid when no failure is detected in any of the stepping sensors and the required braking force sensors. A means for applying a braking force according to the result of detection by at least one of the required braking force sensors to the drive wheels while allocating the traveling energy to the regenerative braking force due to regeneration is provided.

In the braking device according to the present invention, in the above-mentioned first to third structures, when the above-mentioned failure is detected, all the required braking force is applied to the drive wheels as the fluid pressure braking force, while the regenerative braking is applied. It is characterized in that it is provided with means for prohibiting power from acting on the drive wheels.

[0021]

In the first structure of the present invention, a plurality of depression sensors are provided, and each depression sensor detects whether or not the brake pedal is depressed. Further, the detection results of the stepping sensors are compared with each other to determine whether or not a failure has occurred in the stepping sensors. That is, if there is a contradiction between the outputs of a plurality of stepping sensors, it can be considered that one of the stepping sensors related to this contradiction has a failure. By comparing the results with each other, it is possible to detect the presence or absence of a failure in the plurality of stepping sensors. Therefore, in this configuration, it is possible to detect the failure of the depression sensor without using the output of the required braking force sensor such as the hydraulic pressure sensor, and to execute the braking force control with the regenerative braking priority according to the result. it can. In addition, the mutual comparison of the detection results makes it possible, at least in part, to obtain information on which stepping sensor has failed and what mode the failure mode is.

In the second configuration of the present invention, a plurality of required braking force sensors are provided, and each required braking force sensor detects the required braking force. Further, the detection results are compared with each other, and the failure is detected for the plurality of required braking force sensors. That is, if there is a contradiction between the detection results of the plurality of required braking force sensors, it can be considered that a failure has occurred in any of the required braking force sensors related to the contradiction. Therefore, in this configuration, the regeneration priority control can be executed when no failure is detected in any of the required braking force sensors. Further, in the above-mentioned conventional technique, the M / C pressure indicating the required braking force and the W / C pressure of a value obtained by subtracting the differential pressure held by the pressure reducing valve from this M / C pressure are detected, and by comparison between the two. Although a failure of the M / C side oil pressure sensor has been detected, all of the required braking force sensors of the present invention detect the required braking force (corresponding to M / C pressure in the prior art). The failure is accurately detected regardless of whether a member such as a pressure reducing valve is provided on the power transmission path (oil path).

In the third configuration of the present invention, both the action in the first configuration and the action in the second configuration occur. Further, in this configuration, for example, when there is a contradiction between the detection result of a certain depression sensor and the detection result of a certain required braking force sensor, it is determined that one of these sensors has a failure. Therefore, in this configuration, it becomes possible to detect the failure more precisely than in the first and second configurations, and to specify the failed sensor and failure mode in more detail.

Further, in the present invention, when a failure of the stepping sensor or the required braking force sensor is detected, the regenerative braking force is prohibited from acting on the drive wheels, and the required braking force is realized as the fluid pressure braking force. To be done. Therefore, in the present configuration, the required braking force can be reliably realized even if the pedal depression sensor or the required braking force sensor is out of order.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same or corresponding components as those of the conventional example shown in FIGS. 17 to 19 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 and FIG. 2 respectively show the system configuration of the electric vehicle according to the first embodiment of the present invention and the flow of the operation relating to the braking force control of the operation of the ECU 16 in this embodiment. . As shown in Figure 1,
In this embodiment, the hydraulic sensor 36 on the W / C 30a side is eliminated, while two brake lamp switches 20 and 20 are provided in total. Further, as shown in FIG. 2, when it is determined in step 102 that regenerative braking is possible, the output of the hydraulic pressure sensor 26, the output of the brake lamp switch 20, and the output of the brake lamp switch 20 are compared. (104A),
Based on the result, the presence or absence of a failure in these sensors or switches is detected (106A). When a failure is detected in any of the sensors or switches, the regeneration prohibition mode is executed, and in other cases, that is, when no failure is recognized in the hydraulic sensor 26 or the brake lamp switches 20 and 20. The regeneration priority mode is executed. In the regeneration priority mode, first, in step 108A, it is determined whether or not the brake lamp switch 20 is turned on. If this determination is established, the inverter is operated so that the regenerative torque obtained based on the M / C pressure is obtained. The power conversion operation by 12 is controlled (110A), otherwise step 11 above.
Step 112 is executed without going through step 4.

FIG. 3 shows an example of the characteristic setting of the brake lamp switches 20 and 20 in this embodiment. As shown in this figure, in the brake lamp switch 20, the depression amount of the brake pedal 22 is M /
Speaking of the C pressure, the brake lamp switch 20 is set to be turned on when a predetermined small value δ ₂ is reached, and the brake lamp switch 20 is set to be turned on when a predetermined small value δ ₃ is reached. The relationship of 0 <δ ₂ <δ ₃ is established between these minute values. Therefore, in the region where the brake pedal 22 is not depressed or the depression is very shallow (M / C pressure <δ ₂ ), the brake lamp switches 20 and 20 are
Both are off, and on the contrary, the brake pedal 2 is set to the extent that the vehicle operator can consider that he or she intends to brake.
In the region where 2 is stepped on (M / C pressure> δ ₃ ), both brake lamp switches 20 and 20 are on. In the region between them, that is, in the region of δ ₂ <M / C pressure <δ ₃ , only the brake lamp switch 20 is turned on and the brake lamp switch 20 is turned off.

FIG. 4 shows step 1 in this embodiment.
The logic for fault detection performed at 04A and 106A is shown. What is shown in (a) to (c) in the figure is
They are the combination of the output of the hydraulic pressure sensor 26 and the brake lamp switch 20, the combination of the output of the hydraulic pressure sensor 26 and the output of the brake lamp switch 20, and the combination of the output of the brake lamp switch 20 and the output of the brake lamp switch 20, respectively.

In the combination represented by A in FIG. 4A, that is, when the output of the oil pressure sensor 26 is δ ₂ or more and the brake lamp switch 20 is off, the oil pressure sensor 26 and the brake lamp switch 20 are None of these occur when operating normally. Such a state occurs when the hydraulic sensor 26 has a high failure, that is, a failure in a mode in which a detection value higher than the actual M / C pressure is output, or the brake lamp switch 20 has an off failure. That is, this is the case where a failure occurs in the mode in which the brake pedal 22 continues to be turned off even when the brake pedal 22 is sufficiently deeply depressed. Also, FIG.
(B) In the combination represented by B, that is, when the output of the hydraulic pressure sensor 26 is δ ₃ or more, the brake lamp switch 20
The ON state occurs when the hydraulic pressure sensor 26 has a high failure or the brake lamp switch 20 has an OFF failure. And FIG.
The combination indicated by C in (c), that is, the state where the brake lamp switch 20 is off and the brake lamp switch 20 is on is when the brake lamp switch 20 has an off failure or when the brake lamp switch 20 is in the brake state. This is a case where the lamp switch 20 has an ON failure, that is, a failure in a mode in which the brake pedal 22 continues to be OFF even though the brake pedal 22 is not pressed deeply. Considering that it is usually rare that the three types of sensors or switches used in this embodiment, that is, the hydraulic pressure sensor 26 and two or three of the brake lamp switches 20 and 20 fail at the same time, If both A and B described above are satisfied, it can be said that there is a high possibility that the hydraulic sensor 26 has a high failure, and if both A and C are satisfied, the brake lamp switch 20 is turned off. It can be said that there is a high possibility that it is off. Step 104 above
In A and 106A, the oil pressure sensor 26 and the brake lamp switches 20 and 20 are operated in accordance with such a logic.
The failure of is detected.

As described above, since the outputs of the oil pressure sensor 26 and the brake lamp switches 20 and 20 are compared with each other to detect their respective failures, according to the present embodiment, the oil pressure sensor 26 and the brake lamp switch 20 are detected.
It is possible to accurately detect the occurrence of a failure in each of the power supply circuits 20 and 20, and at least partially specify which one of them has failed and what the failure mode is. Therefore, it becomes possible to more appropriately deal with this failure in step 116 and the like. Further, in the above-mentioned conventional example, step 110 is executed when the output of the hydraulic sensor 26 satisfies the predetermined condition, but in the present embodiment, regardless of the output of the hydraulic sensor 26, that is, the brake lamp switch 20.
Since the step 110A is executed only when the output of is turned on, a vehicle having a better feeling than the conventional vehicle can be obtained. That is, the problem that the braking force increases or decreases depending on the presence or absence of a failure in the hydraulic sensor 26 does not occur.
In addition, it suffices to use only one hydraulic pressure sensor (26) having a linear characteristic, while at least 20 of the two brake lamp switches provided in this embodiment use inexpensive switches for cruise control vehicles. Therefore, the system can be configured at a lower cost as a whole.

In this embodiment, when any one of the oil pressure sensor 26 and the brake lamp switches 20 and 20 fails, the regeneration prohibition mode is entered. However, for example, when the brake lamp switch 20 and the oil pressure sensor 26 are not broken and it can be considered that the brake lamp switch 20 is broken, the regeneration priority mode may be set. By doing so, the number of opportunities for the regenerative braking force to act is increased as compared with the above-described embodiment, so that a vehicle with higher energy efficiency can be obtained.
However, in terms of fail-safe performance, as in the above-described embodiment, the hydraulic pressure sensor 26 and the brake lamp switch 20 are provided.
It is better to make a transition to the regeneration prohibition mode if any one of 20 and 20 fails.

FIG. 5 shows a main part of the system configuration of the electric vehicle according to the second embodiment of the present invention. This embodiment is the same as the first embodiment shown in FIG.
8 is added. The hydraulic switch 38 is provided at the same position as the hydraulic sensor 26, that is, on the M / C 24 side when viewed from the pressure reducing valve 32a and the bypass valve 34a. For example, as shown in FIG. 6, the hydraulic switch 38 is turned on when the M / C pressure rises and exceeds the predetermined value P ₁ , and conversely the M / C pressure decreases and the predetermined value P ₂ is set. It is set to turn off when it falls below (P ₂ <P
₁ ).

The output of the hydraulic switch 38 is supplied to the ECU 16. As shown in FIG. 7, in the present embodiment, the output of the hydraulic switch 38 is included in the comparison target at 104B corresponding to the above-mentioned step 104A, and at the step 106B corresponding to the above-mentioned step 106A. This hydraulic switch 38 is also an object of failure detection.

FIG. 8 shows the fault detection logic employed in steps 104B and 106B of this embodiment. 4A to 4C according to the first embodiment.
It has the same contents as (a) to (c). 8D shows a combination of the output of the hydraulic pressure sensor 26 and the output of the hydraulic switch 38, FIG. 8E shows a combination of the output of the brake lamp switch 20 and the output of the hydraulic switch 38, and FIG. The combinations of the output and the output of the hydraulic switch 38 are shown respectively. In the combination represented by D in FIG. 8D, that is, when the output of the hydraulic pressure sensor 26 is P ₃ (> P ₁ ) or more and the hydraulic pressure switch 38 is off, the hydraulic pressure sensor 26 has a high failure. Alternatively, it can be considered that the hydraulic switch 38 is in the off failure state. Further, the combination of E, that is, the state in which the output of the hydraulic pressure sensor 26 is less than P4 (<P ₂ ) and the hydraulic pressure switch 38 is turned on is the hydraulic pressure sensor 2
It can be considered that 6 is a low failure, that is, a failure in a mode that outputs a value lower than the actual M / C pressure, or that the hydraulic switch 38 is in an on failure. The combination of F in FIG. 8E, that is, the brake lamp switch 20 is off and the hydraulic switch 3 is
8 is on, the brake lamp switch 20
Can be considered to be in an off-state failure or the hydraulic switch 38 is in an on-state failure. And
In the combination of G in FIG. 8 (f), that is, when the brake lamp switch 20 is off and the hydraulic switch 38 is on, the brake lamp switch 20 has an off failure or the hydraulic switch 38 has an on failure. Can be considered to be the state.

Therefore, according to the present embodiment, it is possible to specify the failure location and the failure mode more precisely than in the first embodiment. For example, when A, B, and D are all satisfied, it is determined that the hydraulic pressure sensor 26 has a high failure when both A and B are satisfied.
The high failure of the hydraulic sensor 26 can be detected with higher accuracy than in the embodiment. Further, the hydraulic switch 38 is
Since the required braking force sensor is less expensive than the hydraulic pressure sensor 26 that requires linear characteristics, the above-described effect can be obtained without increasing the cost so much. In addition, in this embodiment, any of the effects obtained in the first embodiment described above can be obtained.

FIG. 9 shows the system configuration of an electric vehicle according to the third embodiment of the present invention, and particularly its essential parts.
This embodiment has a configuration in which two hydraulic switches 38 and 38 are provided instead of the hydraulic switch 38 in the second embodiment described above. The M / C pressures at which the hydraulic switches 38 and 38 are turned on / off are set so as to have a slight difference as shown in FIG.

The ECU 16 includes an oil pressure sensor 26, brake lamp switches 20 and 20, and an oil pressure switch 3.
Perform the procedure shown in FIG. 7 based on the outputs of 8 and 38. The fault detection logic adopted at that time is the same as the logic shown in FIG. However, FIG.
Regarding (f), both the hydraulic switches 38 and 38 are executed, and a logic considering the combination of the output of the hydraulic switch 38 and the output of the hydraulic switch 38 is also added.

Therefore, according to the present embodiment, it is possible to perform more precise fault detection as compared with the second embodiment described above.

FIG. 11 shows the system configuration of an electric vehicle according to the fourth embodiment of the present invention, particularly the essential parts thereof. In this embodiment, the oil pressure sensor 26 used in the third embodiment is eliminated. Further, as shown in FIG. 12, in this embodiment, the hydraulic sensor 26 is excluded from the objects of steps 104C and 106C corresponding to the above-mentioned steps 104B and 106B, and step 110 corresponding to the above-mentioned step 110A.
The regenerative torque to be output at B is the hydraulic switch 38.
And 38 outputs.

With this structure, the same effect as that of the third embodiment can be obtained. However, since the regenerative torque is determined by using the hydraulic switches 38 and 38 having the ON / OFF characteristic instead of the hydraulic sensor 26 having the linear characteristic, the regenerative braking characteristic in the regenerative priority mode has a slightly step-like feeling. . In order to improve this feeling and realize a more linear braking characteristic, the number of hydraulic switches may be increased.

FIG. 13 shows the system configuration of an electric vehicle according to the fifth embodiment of the present invention, and particularly its essential parts. In this embodiment, two hydraulic pressure sensors 26 and 26 are provided instead of the hydraulic pressure sensor 26 used in the first embodiment. The braking operation of the ECU 16 is an operation obtained by replacing step 110A in the operation of the first embodiment (FIG. 2) with step 110C shown in FIG. In step 110C, the ECU 16
The average of the two types of M / C pressures detected by the hydraulic pressure sensors 26 and 26 is calculated, and the power conversion operation by the inverter 12 is controlled so that the motor 10 can obtain the regenerative torque corresponding to the calculated average value.

FIG. 15 shows step 104 of this embodiment.
The fault detection logic employed in A and 106A is shown. In particular, FIGS. 15 (a) to (c) and (a) '
(B) ′ has the same contents as those in FIGS. 4A to 4C according to the first embodiment. However, 26 and 26 are used as oil pressure sensors.
2 are used in total, so that FIGS. 15 (a) and 15 (a) 'correspond to FIG. 4 (a), and FIGS. 15 (b) and 15 (b) correspond to FIG. 4 (b). 'Is occurring. Further, FIG. 15D relating to the combination of the output of the hydraulic sensor 26 and the output of the hydraulic sensor 26 is newly generated.

Therefore, according to this embodiment, it is possible to specify the failure location and failure mode more precisely than in the first embodiment. Also, although two hydraulic pressure sensors are used as in the above-mentioned conventional example, these hydraulic pressure sensors 26
Since Nos. 26 and 26 are provided at the same location, that is, on the M / C 24 side, they are not affected by the characteristics of the pressure reducing valve 32a. Furthermore, since the regenerative torque determination using the outputs of both the hydraulic pressure sensors 26 and 26 is executed in step 110C, even if a significant error occurs in one of the hydraulic pressure sensors 26 and 26, the effect is halved. Therefore, it becomes possible to generate an accurate regenerative torque. In addition, the oil pressure sensor 2
Even if one of the characteristics of 6 and 26 deteriorates within a range that cannot be regarded as a failure, the oil pressure sensor (26 or 26) can be used while being tricked, It is possible to reduce the running cost such as the replacement cost of the hydraulic sensor.

FIG. 16 shows a control flow executed by the ECU 16 in the electric vehicle according to the sixth embodiment of the present invention. In this figure, illustration of operations similar to those shown in FIG. 2 is omitted.

In this embodiment, when it is determined that the brake lamp switch 20 is on in the regeneration priority mode (108A), it is further determined whether the brake lamp switch 20 is on (108A).
B), step 110A is first executed when it is determined that the switch is on. That is, step 110A is executed only when both the brake lamp switches 20 and 20 are turned on, and step 112 is executed otherwise. Even when the control of the regenerative torque is executed in such a procedure, the same effect as that of the above-described first embodiment can be obtained. In addition, the same modification can be applied to the second to fifth embodiments.

In the above description, the brake lamp switch is shown as an example of the depression sensor for detecting whether or not the brake pedal 22 is depressed, but the present invention is not limited to the brake lamp switch. Further, as the required braking force sensor for detecting the required braking force given as the depression amount of the brake pedal 22, a hydraulic pressure sensor for linearly detecting the M / C pressure and a hydraulic switch for ON / OFF detection are shown. The sensor or switch is not limited to the above. For example, the present invention can be carried out for a stroke sensor that detects the stroke of the brake pedal 22. In addition, in each of the above-described embodiments, it is not specified which of the front and rear wheels is the drive wheel, but the present invention can be applied to both front wheel drive and rear wheel drive. It can be applied even when driving.

[0047]

As described above, according to the first configuration of the present invention, a plurality of depression sensors for detecting whether or not the brake pedal is depressed are provided, and the depression results are obtained by mutual comparison of the detection results. Since the failure of the sensor is detected, the failure detection performance can be improved as compared with the conventional case. Further, since the braking force distribution control with the regeneration priority can be started regardless of whether or not there is a failure in the required braking force sensor such as the hydraulic pressure sensor, it is possible to realize an electric vehicle having a better feeling than in the past. Further, at least in part, it is possible to know which stepping sensor has failed and what the failure mode is, so that the detected failure can be appropriately dealt with.

According to the second configuration of the present invention, a plurality of required braking force sensors for detecting the required braking force are provided, and the detection results are compared with each other to detect a failure. It is possible to detect the failure of the required braking force sensor more accurately than in the configuration in which the pressure reducing valve is interposed between the individual hydraulic pressure sensors, and it is possible to appropriately cope with a change or variation in the output of the required braking force sensor with time. Furthermore, at least in part, it is possible to identify which required braking force sensor has failed and what the failure mode is, so that the detected failure can be dealt with more appropriately. It will be possible.

According to the third structure of the present invention, both the effects of the first structure and the second structure can be obtained. Further, since it becomes possible to detect the failure of the required braking force sensor by the output of the stepping sensor, the first and second
It becomes possible to deal with it more precisely and carefully than the simple combination of the configurations of.

Further, according to the present invention, when the failure is detected, the required braking force is realized exclusively by the fluid pressure braking force, so that the required braking force can be surely realized, and the higher fail is exerted. Safe performance can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of an electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of operation of an ECU in this embodiment.

FIG. 3 is a diagram showing an example of characteristic setting of a brake lamp switch in this embodiment.

FIG. 4 is a conceptual diagram showing a fault detection logic in this embodiment.

FIG. 5 is a block diagram showing a main part of a system configuration of an electric vehicle according to a second embodiment of the present invention.

FIG. 6 is a diagram showing an example of characteristic setting of a brake lamp switch and a hydraulic switch in this embodiment.

FIG. 7 is a flowchart showing a flow of operation of an ECU in this embodiment.

FIG. 8 is a conceptual diagram showing a fault detection logic in this embodiment.

FIG. 9 is a block diagram showing a main part of a system configuration of an electric vehicle according to a third embodiment of the present invention.

FIG. 10 is a diagram showing an example of characteristic setting of a brake lamp switch and a hydraulic switch in this embodiment.

FIG. 11 is a block diagram showing a main part of a system configuration of an electric vehicle according to a fourth embodiment of the present invention.

FIG. 12 is a flowchart showing a flow of operations of the ECU in this embodiment.

FIG. 13 is a block diagram showing a main part of a system configuration of an electric vehicle according to a fifth embodiment of the present invention.

FIG. 14 is a flowchart showing a flow of operations of the ECU in this embodiment.

FIG. 15 is a conceptual diagram showing a fault detection logic in this embodiment.

FIG. 16 is a flowchart showing a flow of operations of an ECU in the electric vehicle according to the sixth embodiment of the present invention.

FIG. 17 is a block diagram showing a system configuration of an electric vehicle according to a conventional example.

FIG. 18 is a flowchart showing a flow of operation of an ECU in a conventional example.

FIG. 19 is a conceptual diagram showing the principle of failure detection in this conventional example.

[Explanation of symbols]

10 motors, 12 inverters, 14 batteries, 1
6 ECU, 20, 20 Brake lamp switch, 22 Brake pedal, 24 Master cylinder (M
/ C), 26, 26 oil pressure sensor, 28a, 28b
Brake wheel, 30a, 30b Wheel cylinder (W / C), 32a, 32b Pressure reducing valve, 34a, 34
b Bypass valve, 38, 38, 38 Hydraulic switch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoyasu Enomoto 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (4)

[Claims] 1. A plurality of stepping sensors for respectively detecting whether or not a brake pedal is stepped on, and means for detecting the failure of the plurality of stepping sensors by comparing the detection results with each other. When no failure is detected with respect to the depression sensor as well, means for applying the required braking force to the drive wheels while distributing the fluid pressure braking force due to the incompressible fluid and the regenerative braking force due to regeneration of the running energy is provided. A braking device, which is mounted on an electric vehicle. 2. A plurality of required braking force sensors for respectively detecting a required braking force given by a fluid pressure according to a stepping amount of a brake pedal, and the detection results are mutually compared to obtain the plurality of required braking forces. A means for detecting the failure of the sensor, and when no failure is detected for any of the required braking force sensors, while distributing to the fluid pressure braking force by the incompressible fluid and the regenerative braking force by regeneration of running energy, A braking device comprising: a unit that applies a braking force according to a result of detection by at least one of the required braking force sensors to driving wheels, and is mounted on an electric vehicle. 3. A plurality of stepping sensors for respectively detecting whether or not the brake pedal is stepped on, and a plurality of required braking force sensors for respectively detecting a required braking force given as a fluid pressure corresponding to the stepping amount of the brake pedal. By comparing the detection results with each other, the means for detecting the failure of the plurality of stepping sensors and the plurality of required braking force sensors, and the failure of any of the stepping sensors and the required braking force sensors are detected. If not, the braking force according to the detection result of at least one of the required braking force sensors is applied to the drive wheels while distributing to the fluid pressure braking force by the incompressible fluid and the regenerative braking force by the regeneration of running energy. A braking device comprising: a means for causing the electric vehicle to be mounted on an electric vehicle. 4. The braking device according to claim 1, wherein when the failure is detected, all of the required braking force acts on the drive wheels as a fluid pressure braking force, while the regenerative braking force acts on the drive wheels. A braking device comprising means for prohibiting the operation.