JP7305856B2 - pneumatic brake system - Google Patents

Description

The present invention relates to pneumatic brake systems that use air to actuate brakes.

In recent years, as one of advanced driving techniques, a system has been developed that realizes platooning in which a plurality of vehicles communicate with each other and form a platoon. In particular, for freight vehicles such as trucks and buses, there has been proposed a platooning system in which a leading vehicle driven by a driver and a trailing vehicle unmanned or with a supervisor ride in a platoon. In the following vehicle, various controls are performed following the behavior of the leading vehicle (see Patent Literature 1, for example). For example, in brake control, when the leading vehicle applies its brakes, the trailing vehicle follows and applies its brakes.

Many freight vehicles are equipped with pneumatic brake systems that use air to actuate the brakes. Therefore, in the trailing vehicle equipped with the pneumatic brake system, each actuator constituting the pneumatic brake system is controlled following the brake control of the leading vehicle.

By the way, the following vehicle is either unmanned or automatically driven with vehicle behavior monitored by an observer. is required for redundancy. For example, Patent Literature 1 proposes a platooning control system in which brake systems are multiplexed.

JP 2007-233965 A

In the platooning control system described above, when the control device detects an abnormality in the electric system such as the position detection device, it performs control to activate the emergency brake. However, malfunctions that can occur in the pneumatic brake system are not limited to malfunctions in the electrical system. For example, no consideration is given to promptly switching from one brake module to the other when an abnormality occurs in a part of the structure such as a pipe or a valve device in one of the brake modules. Therefore, there is a demand to further increase the redundancy of the pneumatic brake system so as to be able to respond even when an abnormality occurs in a part of the structure such as piping and valve devices.

These problems are not limited to vehicles that run in platoons, but are generally common to vehicles equipped with a pneumatic brake system that run independently without forming a platoon, such as self-driving vehicles.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pneumatic brake system capable of increasing redundancy.

A pneumatic brake system that solves the above problems is a pneumatic brake system that supplies air to a brake mechanism of a vehicle to operate the brake and discharges air from the brake mechanism to release the brake. a safety air supply unit operated by a brake control device for supplying air to the brake mechanism, the safety air supply unit, and supplying air to the brake mechanism through a path separate from the safety air supply unit a shuttle valve that is connected to a brake air supply circuit that is connected to the brake air supply circuit and allows air to flow only in a direction from the high pressure side of the brake air supply circuit and the brake air supply circuit toward the brake mechanism, The air supply and the shuttle valve are provided for each wheel of the vehicle.

According to the above configuration, air is supplied to the brake mechanism from the high pressure side of the safety air supply section and the other air supply circuit by the shuttle valve. Therefore, even if one or both of the safety air supply unit and other air supply circuit malfunction, or if an abnormality occurs in the safety brake control device, air is supplied to the brake mechanism to operate the brake. can be made Therefore, the redundancy of the pneumatic brake system can be enhanced. Also, since the safety air supply circuit and the shuttle valve are provided for each wheel, it is possible to improve the responsiveness of brake control in an emergency.

The pneumatic brake system includes a forced brake solenoid valve controlled by a main control device that outputs a braking request to a safety brake control device that controls the safety air supply unit. In an energized state energized by the main control device, an air supply source storing compressed air is cut off from supplying air to the brake mechanism side, and in a non-energized state air is supplied from the air supply source to the brake mechanism side. and the shuttle valve allows air to be supplied from the forced brake solenoid valve side to the brake mechanism side when air is supplied from the forced brake solenoid valve.

According to the above configuration, the forced brake solenoid valve controlled by the main controller supplies air from the air supply source to the brake mechanism in a non-energized state. The shuttle valve also allows air to be supplied from the side of the safety electromagnetic valve to the side of the brake mechanism. Therefore, even if an abnormality occurs in the main control device, the brake can be forcibly operated.

In the pneumatic brake system, an air-driven suspension system is connected between the forced brake solenoid valve and the safety air supply section to supply air to the brake mechanism in response to an increase in the load of the vehicle. Preferably, a valve arrangement is provided to vary the supply to a higher rate.

According to the above configuration, the amount of air supplied to the brake mechanism increases according to the load of the vehicle, so the braking force can be increased when the load is large. The valve device also communicates with an air-driven suspension system and varies the amount of air supplied according to the air pressure in the suspension system. Therefore, even if an abnormality occurs in the electrical system of the control device or the like, the braking force can be mechanically changed in accordance with the load, thereby further enhancing the redundancy of the pneumatic brake system.

In the pneumatic brake system, the safety brake control device detects an abnormality in a brake control device that controls an air supply circuit different from the safety air supply section, and brakes the brake based on the braking request of the main control device. Preferably, air is supplied to the mechanism to drive or stop the vehicle at a predetermined speed.

According to the above configuration, the safety brake control device is controlled based on a braking request from the main control device, so that the vehicle can be driven even if an abnormality occurs in the brake control device. Therefore, the redundancy of the pneumatic brake system can be further enhanced.

In the above pneumatic brake system, when an abnormality occurs in the brake control device that controls an air supply circuit different from the safety air supply unit and in the main control device, the forced brake solenoid valve is deenergized and the brake is applied. is preferably compulsorily activated.

According to the above configuration, the brake is forcibly actuated when an abnormality occurs in the brake control device and the main control device even if an abnormality does not occur in the safety brake control device. Therefore, the redundancy of the pneumatic brake system can be further enhanced.

ADVANTAGE OF THE INVENTION According to this invention, the redundancy of a pneumatic brake system can be improved.

FIG. 1 is a schematic diagram of vehicles that are equipped with the pneumatic brake system and that form a platoon in one embodiment of the pneumatic brake system. FIG. 4 is a schematic diagram showing the connection state of the ECU of the pneumatic brake system of the same embodiment. Schematic which shows the structure of the pneumatic brake system of the same embodiment. 4 is a flowchart showing the operation of a second EBSECU in the same embodiment; FIG. 10A is a conceptual diagram showing state transitions when an abnormality first occurs in the first EBSECU, and FIG. 4 is a conceptual diagram showing state transitions; FIG. FIG. 4 is a conceptual diagram showing a state transition when an abnormality first occurs in a traction ECU in the same embodiment;

An embodiment of a vehicle with a pneumatic brake system is described below.
The platooning will be described with reference to FIG. Here, the vehicles 100 that form the platoon are trucks (also referred to as cargo vehicles) integrally provided with cargo beds. A platoon is formed by a leading vehicle 100a driven by a driver and a trailing vehicle 100b unmanned or with an observer. The observer monitors the behavior of the vehicle and basically does not drive it. The leading vehicle 100a and the following vehicle 100b travel while maintaining a preset inter-vehicle distance.

As shown in FIG. 2, the vehicle 100 includes a first traction ECU (Electronic Control Unit) 11A as a main control device and a second traction ECU 11B as a main control device. Various systems of the vehicle 100 are controlled by commands from either the first traction ECU 11A or the second traction ECU 11B, and platooning is performed. For example, the second traction ECU 11B controls the vehicle 100 even if an abnormality occurs in the first traction ECU 11A. When the first traction ECU 11A and the second traction ECU 11B are described without being distinguished from each other, they will simply be referred to as the traction ECU 11. FIG.

The traction ECU 11 of the leading vehicle 100a and the traction ECU 11 of the following vehicle 100b transmit and receive various information through wireless communication. The leading vehicle 100a brakes according to the driver's brake operation, and the trailing vehicle 100b follows the preceding vehicle 100 and brakes when the preceding vehicle 100 decelerates. That is, the following vehicle 100b has a pneumatic brake system that can apply brakes following the preceding vehicle 100 . Since the leading vehicle 100a is a vehicle operated by a driver, it does not need to be equipped with a pneumatic brake system like the trailing vehicle 100b, but may be equipped with a pneumatic brake system having the same configuration. . In this embodiment, the pneumatic brake system of the leading vehicle 100a and the pneumatic brake system of the trailing vehicle 100b have the same configuration. In addition, in FIG. 1, the platoon is formed by three vehicles 100, but a plurality of vehicles other than three may be formed.

A schematic configuration of the pneumatic brake system of vehicle 100 will be described with reference to FIGS. 2 and 3. FIG. The pneumatic brake system operates a service brake that varies the braking force by air pressure, and a parking brake that applies a predetermined braking force to the wheels by the biasing force of a spring.

As shown in FIG. 2, the pneumatic brake system 10 includes, in addition to the traction ECU 11, a first EBSECU 15A as a brake control device and a second EBSECU 15B as a safety brake control device. The first EBSECU 15A is an ECU having a higher priority than the second EBSECU 15B, and controls the actuators that constitute the pneumatic brake system 10 during normal times when there is no abnormality in itself. The second EBSECU 15B controls the pneumatic brake system 10 in an emergency when the first EBSECU 15A malfunctions. In addition, an emergency is when an abnormality occurs in both the first traction ECU 11A and the second traction ECU 11B, except when the first EBSECU 15A malfunctions. including when an abnormality occurs in

The first traction ECU 11A, the second traction ECU 11B, the first EBSECU 15A, and the second EBSECU 15B are connected to an in-vehicle network 19 . A vehicle speed sensor 53 is also connected to the in-vehicle network 19 . When the first traction ECU 11A, the second traction ECU 11B, the first EBS ECU 15A, and the second EBS ECU 15B are not distinguished from each other and are simply described as nodes connecting to the in-vehicle network 19, they are simply referred to as the ECU 20. For example, the in-vehicle network is a CAN (Controller Area Network), but may be another in-vehicle network such as FlexRay (registered trademark) or Ethernet (registered trademark). A communication control unit (not shown) that detects communication errors and the like is connected to the in-vehicle network 19 . Each ECU 20 attaches its own ID and sends a predetermined communication message to the in-vehicle network 19 , and acquires the communication message to be acquired from the in-vehicle network 19 .

Next, as shown in FIG. 3, the pneumatic brake system 10 supplies air stored in an air storage tank 21 or other tanks to a brake chamber 50 as a brake mechanism. Although FIG. 3 shows only a pair of front wheels 51 and a pair of rear wheels 52 as drive wheels, the number of front wheels 51 and the number of rear wheels 52 are not particularly limited. For example, vehicle 100 may be provided with a pair of front wheels 51 and two pairs of rear wheels 52 . A brake chamber 50 is provided for each wheel. The brake chambers 50 each have an air reservoir for the service brake and an air reservoir for the parking brake. Further, the brake chamber 50 is provided with a spring that imparts an urging force to the wheel to stop the rotation of the wheel. When air is supplied to the service brake air storage chamber, the service brake operates, and the braking force increases as the amount of air supplied increases. When the air is discharged from the service brake air storage chamber, the service brake is released. On the other hand, when more than a predetermined amount of air is supplied to the air storage chamber for the parking brake, the force of the spring is released, and when the air is discharged from the air storage chamber for the parking brake, the force of the spring is applied to the wheels Granted.

Further, the front wheels 51 and the rear wheels 52 are provided with vehicle speed sensors 53 for detecting the rotational speed of the wheels. The vehicle speed sensor 53 outputs a vehicle speed pulse signal to the in-vehicle network 19 (see FIG. 2). Further, a pressure sensor 54 for detecting the pressure of the supply passage is provided in the supply passage connected to the service brake air storage chamber of the brake chamber 50 .

Air compressed by a compressor 22 and dried by an air dryer 23 containing a desiccant is stored in an air storage tank 21 . The air storage tank 21 is connected to a protection valve 24 via piping. The protection valve 24 distributes the air supplied from the air storage tank 21 to a parking brake tank 25 , a rear wheel brake tank 26 and a front wheel brake tank 27 .

The front wheel brake tank 27 is connected to an axle modulator 30 via a brake valve 31 . Axle modulator 30 controls the supply and discharge of air to brake chamber 50 provided in front wheel 51 . The brake valve 31 includes a front wheel control section 31A and a rear wheel control section 31B, and is controlled by the first EBSECU 15A. The axle modulator 30 is controlled by the first EBSECU 15A.

The front wheel brake tank 27 is connected to an axle modulator 30 via a brake valve 31 . During manned operation in which the vehicle 100 is driven by the driver, the first EBSECU 15A receives a position detection signal from a sensor that detects the position of a brake pedal (not shown) operated by the driver, and controls the brake valve 31. to supply air to the axle modulator 30 . When the vehicle 100 is unmanned, the first EBSECU 15A controls the brake valve 31 based on information such as deceleration information transmitted from the leading vehicle or the like.

The axle modulator 30 has a first input port connected to a supply passage 60 communicating with the front wheel control section 31A of the brake valve 31, and a second input port connected to the supply passage 61 communicating with the front wheel brake tank 27. ing. Further, the axle modulator 30 has an output port connected to a safety modulator 32L provided corresponding to the left front wheel 51, and an output port connected to a safety modulator 32R provided corresponding to the right front wheel 51. ing. When the air pressure signal sent from the front wheel controller 31A of the brake valve 31 is input to the first input port, the axle modulator 30 receives the air supplied from the front wheel brake tank 27 to the second input port, and the safety modulator 32L, 32R, respectively.

Since the left front wheel security modulator 32L and the right front wheel security modulator 32R have the same configuration, only the left front wheel security modulator 32L will be described. The safety modulator 32L includes a safety air supply 33 and a shuttle valve 34. As shown in FIG. The safety air supply unit 33 includes an electromagnetic valve (not shown) controlled by the second EBSECU 15B. The safety air supply unit 33 is connected to a suspension tank 28 provided in an air suspension system (pneumatically driven suspension system) of the vehicle 100 . The safety air supply section 33 is also connected to the brake chamber 50 via the shuttle valve 34 . Air supplied from the compressor 22 via the air dryer 23 is stored in the suspension tank 28 . In an emergency when an abnormality occurs in the first EBSECU 15A or the like, the second EBSECU 15B controls the safety air supply section 33 to supply air to the brake chamber 50 side.

The shuttle valve 34 is connected to the safety air supply section 33 and the axle modulator 30, and directs the flow of air from the safety air supply section 33 side or the axle modulator 30 side, whichever has the higher pressure, to the brake chamber 50 side. allow. As a result, failures other than electrical system failures, such as air leaks or mechanical abnormalities between the air storage tank 21 and the axle modulator 30, or leaks in the piping on the axle modulator 30 side, have occurred. Even in this case, since either the safety air supply portion 33 side or the axle modulator 30 side has a higher pressure, the air is supplied to the brake chamber 50 from the higher pressure side. The shuttle valve 34 is also connected to an ABS (Antilock Brake System) valve 36 . The ABS valve 36 constitutes an antilock braking system for the front two wheels. The ABS valve 36 is controlled by the first EBSECU 15A. At least one of the axle modulator 30 and the safety air supply section 33 may have the ABS function.

On the other hand, the rear wheel brake tank 26 is connected to an axle modulator 40 . Axle modulator 40 controls the supply and discharge of air to brake chamber 50 provided in rear wheel 52 . The axle modulator 40 is controlled by the first EBSECU 15A. The axle modulator 40 has a first input port connected to a supply passage 62 communicating with the rear wheel control section 31B of the brake valve 31, and a second input port connected to a supply passage 63 communicating with the rear wheel brake tank 26. It has The axle modulator 40 also has an output port connected to a safety modulator 42L provided on the left rear wheel 52 and an output port connected to a safety modulator 42R provided on the right rear wheel 52. When the axle modulator 40 inputs the air pressure signal sent from the rear wheel controller 31B of the brake valve 31 to the first input port connected to the supply passage 62, the signal is supplied from the rear wheel brake tank 26 to the second input port. The extracted air is distributed to safety modulators 42L and 42R, respectively.

The rear wheel brake tank 26 is connected to an axle modulator 40 via a brake valve 31 . During manned operation in which the vehicle 100 is driven by the driver, the first EBSECU 15A receives a position detection signal from a sensor that detects the position of a brake pedal (not shown) operated by the driver, and controls the brake valve 31. . When the vehicle 100 is in unmanned operation, the first EBSECU 15A controls the brake valve 31 and supplies air to the axle modulator 40 based on information such as deceleration information transmitted from the leading vehicle or the like.

Since the security modulator 42L for the left rear wheel and the security modulator 42R for the right rear wheel have the same configuration, only the left security modulator 42L will be described. The security modulators 42L, 42R for the rear wheels have the same configuration as the security modulators 32L, 32R for the front wheels, except for the state of connection to the tank or the like. The safety modulator 42L includes a safety air supply section 33 and a shuttle valve 34 controlled by a deceleration command from the second EBSECU 15B. The safety air supply unit 33 has the same configuration as the safety air supply unit 33 provided for the front wheels 51, and includes an electromagnetic valve controlled by the second EBSECU 15B. The safety air supply 33 for the rear wheels 52 is also connected to the suspension tank 28 .

The parking brake tank 25 is also connected to a parking brake control valve 55 and a parking brake relay valve 56 . The parking brake control valve 55 outputs an air pressure signal to the parking brake relay valve 56 under the control of the first EBSECU 15A and the like. The parking brake relay valve 56 opens when an air pressure signal is input from the parking brake control valve 55 , and communicates the parking brake tank 25 with the parking brake air storage chamber of the brake chamber 50 . As a result, air is supplied to the air storage chamber for the parking brake, and the parking brake is released. The parking brake relay valve 56 may be an electromagnetic valve controlled by the first EBSECU 15A or the like.

Between the parking brake control valve 55 and the parking brake relay valve 56, a signal supply path 65 for a safety brake valve 71 as a forced brake electromagnetic valve is connected. The safety brake valve 71 constitutes a forced brake modulator 70 together with a load sensing valve 72 (regulating valve) as a valve device. At least one forced brake modulator 70 is provided for one vehicle 100 . In this embodiment, one forced brake modulator 70 is provided. Also, the forced brake modulator 70 is controlled by the electronic traction ECU 11 . The safety brake valve 71 is an electromagnetic valve controlled by either the first traction ECU 11A or the second traction ECU 11B. In other words, the safety brake valve 71 can be controlled by either the first traction ECU 11A or the second traction ECU 11B.

The load sensing valve 72 is provided in a supply line connecting the safety brake valve 71 and the safety modulators 42L, 42R in series with them. The load sensing valve 72 can adjust the amount of air supplied to the service brake air reservoir of the brake chamber 50 . A load sensing valve 72 is connected to the air suspension system. The pressure at the connection port of the load sensing valve 72 with the air suspension system is the same pressure as the air suspension system. When the vehicle 100 is heavily loaded with cargo, the pressure at the connection port increases. When the pressure on the connection port side of the load sensing valve 72 exceeds a predetermined value, the load sensing valve 72 increases the amount of air supplied to the safety modulators 42L, 42R of the rear wheels 52, which are driving wheels. Note that the load sensing valve 72 may be omitted if, for example, a configuration other than the load sensing valve 72 is used so that the pressure of the connection port can be adjusted according to the load of the cargo or the like.

The safety brake valve 71 has a signal input port connected to the signal supply path 65, two connection ports connected to the safety modulators 32L and 32R of the front wheels 51 and the safety modulators 42L and 42R of the rear wheels 52, and an air supply source. and an input port connected to a tank-side supply passage 66 to which air is supplied from the suspension tank 28 . The safety brake valve 71 is energized by either the first traction ECU 11A or the second traction ECU 11B in a normal state, ie, in a normal state, and cuts off air supply to the safety modulators 32L, 32R, 42L, 42R. Further, the safety brake valve 71 is deenergized in a predetermined state in which an abnormality occurs, and supplies air to the safety modulators 32L, 32R, 42L, 42R.

When the air is discharged from the air storage chamber for the parking brake, the biasing force of the spring is applied to the wheels and the parking brake is activated. At this time, the pneumatic signal is not input to the signal input port of the safety brake valve 71 . When a predetermined amount of air is introduced into the air storage chamber for the parking brake, the parking brake is released. At this time, an air pressure signal is input to the signal input port of the safety brake valve 71 through the signal supply path 65 . When an air pressure signal is input to the signal input port, the safety brake valve 71 can supply the air stored in the suspension tank 28 to the safety modulators 32L, 32R, 42L, 42R. At this time, the pressure on the side of the safety brake valve 71 becomes higher than that on the side of the axle modulators 30, 40, so the shuttle valve 34 allows air to flow from the side of the safety brake valve 71 to the side of the brake chamber 50.

Also, the second EBSECU 15B acquires the pressure detection signal of the pressure sensor 54 . The second EBSECU 15B learns the relationship between pressure and deceleration based on the pressure detection signal. The deceleration is calculated by the second EBSECU 15B based on the vehicle speed signal obtained from the vehicle speed sensor 53 via the in-vehicle network 19 . Alternatively, the second EBSECU 15B acquires the deceleration calculated by the traction ECU 11 from the in-vehicle network 19 . The second EBSECU 15B controls the safety modulators 32L, 32R, 42L, 42R based on the deceleration request of the traction ECU 11 and the learning result so that the vehicle 100 is decelerated to a predetermined speed. The second EBSECU 15B may learn the relationship between velocity and pressure in addition to the relationship between deceleration and pressure.

Next, referring to FIG. 4, the operation of the second EBSECU 15B will be described together with its procedure. The second EBSECU 15B controls the brake in a predetermined state in which an abnormality has occurred in the first EBSECU 15A, and otherwise does not interfere with the brake control of the first EBSECU 15A. It is also assumed that no abnormality has occurred in the second EBSECU 15B. Note that the following procedure is an example, and control may be performed by procedures other than the following procedure.

For example, when the ignition switch is turned on, the second EBSECU 15B determines whether or not all the ECUs 20 connected to the in-vehicle network 19 or a predetermined ECU 20 among them has an abnormality (step S1). Each ECU 20 can determine whether or not there is an abnormality in the ECU 20, which is the source of the communication message, based on the fact that the predetermined communication message is received via the in-vehicle network 19 or the predetermined communication message is not received. It is possible. Alternatively, the second EBSECU 15B determines whether there is an abnormality in the ECU 20 based on a message or the like that is transmitted when a communication control unit that controls communication of the in-vehicle network 19 detects an error. Alternatively, the second EBSECU 15B may determine whether the ECU 20 is abnormal by another method.

When the second EBSECU 15B determines that there is no abnormality in any of the ECUs 20 to be determined (step S1: NO), the second EBSECU 15B repeats the determination of the presence or absence of abnormality (step S1). On the other hand, when the second EBSECU 15B determines that an abnormality has occurred in any of the ECUs 20 to be determined (step S1: YES), it determines whether the ECU 20 in which the abnormality has occurred is the first EBSECU 15A (step S2). ).

When the second EBSECU 15B determines that an abnormality has occurred in the first EBSECU 15A (step S2: YES), it determines whether or not both traction ECUs 11 have an abnormality (step S3). If both traction ECUs 11 have an abnormality (step S3: YES), the traction ECU 11 does not energize the safety brake valve 71 and the safety brake valve 71 is in a non-energized state, so forced braking is activated (step S4). That is, the air stored in the suspension tank 28 is supplied to the safety modulators 32L, 32R, 42L, 42R via the safety brake valve 71. As shown in FIG. As a result, the pressure on the side of the safety brake valve 71 becomes higher than on the side of the axle modulators 30 and 40, so the shuttle valve 34 allows air to flow from the side of the safety brake valve 71 to the side of the brake chamber 50.

In step S3, when the second EBSECU 15B determines that both traction ECUs 11 are not abnormal or one of the traction ECUs 11 is abnormal (step S3: NO), the second EBSECU 15B Based on the deceleration request, brake control for deceleration is performed (step S5). Specifically, the second EBSECU 15B controls the solenoid valves of the security modulators 32L, 32R, 42L, 42R. Air is supplied from the suspension tank 28 to the brake chamber 50 via the safety modulators 32L, 32R, 42L, 42R. At this time, the second EBSECU 15B acquires the pressure value detected by the pressure sensor 54 . The second EBSECU 15B also targets the deceleration or the like instructed by the traction ECU 11, and adjusts the amount of air supply so that the vehicle 100 reaches a predetermined speed based on the acquired pressure value and learning result. As a result, the vehicle 100 decelerates to a predetermined speed within a range of, for example, 20 km/h or more and 40 km/h or less, and runs while maintaining that speed.

On the other hand, when the second EBSECU 15B determines in step S2 that no abnormality has occurred in the first EBSECU 15A (step S2: NO), the second EBSECU 15B determines whether abnormality has occurred in both traction ECUs 11 ( step S6). When the second EBSECU 15B determines that both of the traction ECUs 11 are abnormal (step S6: YES), the safety brake valve 71 is de-energized, so the forced brake is mechanically operated (step S7). .

If the second EBSECU 15B determines in step S6 that an abnormality has occurred in the first traction ECU 11A or the second traction ECU 11B (step S6: NO), an abnormality has already occurred in one of the ECUs 20 in step S1. Since it is determined that the first EBSECU 15A is normal and it is determined in step S2 that no abnormality has occurred in the first EBSECU 15A, one of the first EBSECU 15A and the traction ECU 11 is operating normally. In this case, the first EBSECU 15A performs normal brake control (step S8).

Even after any of the forced braking (steps S4 and S7), the deceleration running (step S5), and the brake control by the first EBSECU 15A (step S8) is performed, the second EBSECU 15B determines abnormality while the ignition switch is in the ON state. are repeated (steps S1 to S8). While the abnormality determination is repeated in this way, for example, when only the first traction ECU 11A becomes abnormal first and then the first EBSECU 15A becomes abnormal, the brake control by the first EBSECU 15A is shifted to deceleration running. . That is, the brake control changes stepwise according to the level (degree) of the abnormality in the pneumatic brake system.

Next, with reference to FIGS. 5 and 6, the state transition of brake control according to the level of abnormality will be described.
FIG. 5(a) shows state transition when an abnormality first occurs in the first EBSECU 15A. When there is no abnormality in any ECU 20, brake control is performed by the first EBSECU 15A (state 200). In this state, when an abnormality first occurs in the first EBSECU 15A, the second EBSECU 15B detects the abnormality in the first EBSECU 15A and performs deceleration running by the second EBSECU 15B (state 201).

When an abnormality occurs in the second EBSECU 15B while deceleration is maintained, the first traction ECU 11A or the second traction ECU 11B detects the abnormality in the first EBSECU 15A or the second EBSECU 15B, deenergizes the safety brake valve 71, and Compulsory braking is activated (state 203).

In the state where deceleration is maintained (state 201), when an abnormality occurs in one of the traction ECUs 11, the second EBSECU 15B detects the abnormality in one of the first EBSECU 15A and the traction ECU 11, and performs deceleration by the second EBSECU 15B. (State 204). Furthermore, when an abnormality occurs in the other traction ECU 11 that has been operating normally, the safety brake valve 71 is de-energized, and forced braking is activated (state 205).

In the state where deceleration is maintained (state 201), if an abnormality occurs in both traction ECUs 11 at the same time, the safety brake valve 71 is de-energized and forced braking is activated (state 206).

It should be noted that the forced braking operation (for example, state 206, etc.) when both of the traction ECUs 11 have failed has timing corresponding to the vehicle 100 in which both of the traction ECUs 11 have failed. On the other hand, when one of the traction ECUs 11 fails, the forced braking is activated (for example, state 203), since the normal traction ECU 11 can adjust the brake timing of the vehicles forming the platoon, collision avoidance with the following vehicles is possible. Easy.

FIG. 5(b) shows state transition when an abnormality first occurs in the second EBSECU 15B. If there is no abnormality in any of the ECUs 20, brake control is performed by the first EBSECU 15A (state 200). In this state, when an abnormality first occurs in the second EBSECU 15B, since the second EBSECU 15B does not interfere with the brake control of the first EBSECU 15A, the first EBSECU 15A performs normal brake control (state 210).

If an abnormality occurs in the first EBSECU 15A while normal brake control is maintained (state 210), the first traction ECU 11A, the second traction ECU 11B, or both detect the abnormality in the first EBSECU 15A and the second EBSECU 15B, and The brake valve 71 is de-energized to operate the forced brake (state 211).

In the state where normal brake control is maintained (state 210), if an abnormality occurs in one of the traction ECUs 11, the first EBSECU 15A can perform brake control, so normal brake control is performed (state 212). Next, when an abnormality occurs in the first EBSECU 15A, the normally operating traction ECU 11 de-energizes the safety brake valve 71 to operate forced braking (state 213).

In the state where normal brake control is maintained (state 210), if an abnormality occurs in both traction ECUs 11 at the same time, the safety brake valve 71 is de-energized and forced braking is mechanically operated (state 214). ).

FIG. 6 shows state transitions when an abnormality first occurs in either the first traction ECU 11A or the second traction ECU 11B. If there is no abnormality in any of the ECUs 20, brake control is being performed by the first EBSECU 15A (state 200). In this state, when an abnormality occurs first in one of the traction ECUs 11, the first EBSECU 15A can perform brake control, so normal brake control is performed (state 220).

When an abnormality occurs in the first EBSECU 15A while the normal brake control is maintained (state 220), the second EBSECU 15B detects the abnormality in the first EBSECU 15A and performs deceleration driving by the second EBSECU 15B (state 221). In the state where deceleration is maintained (state 221), if an abnormality occurs in the other traction ECU 11 and both traction ECUs 11 are in an abnormal state, the safety brake valve 71 is de-energized. active (state 222). Further, when an abnormality occurs in the second EBSECU 15B while the deceleration is maintained (state 221), the normal traction ECU 11 detects the abnormality in the first EBSECU 15A and the second EBSECU 15B, and deenergizes the safety brake valve 71. , activates the forced brake (state 223).

If an abnormality occurs in the second EBSECU 15B while the normal brake control is maintained (state 220), the first EBSECU 15A can perform brake control, so normal brake control is performed (state 224). Next, when an abnormality occurs in the traction ECU 11 which has been operating normally, the safety brake valve 71 is de-energized, and the forced brake is mechanically operated (state 225). Alternatively, even if an abnormality occurs in the first EBSECU 15A following the one traction ECU 11 and the second EBSECU 15B, the normally operating traction ECU 11 deenergizes the safety brake valve 71 and activates the forced brake (state 226).

In the state where normal brake control is maintained (state 220), if an abnormality occurs in the normally operating traction ECU 11 at the same time, the safety brake valve 71 is de-energized, and forced braking is mechanically activated. (state 227).

As described above, according to the above embodiment, the following effects can be obtained.
(1) The shuttle valve 34 supplies air to the brake chamber 50 from the high pressure side of the safety air supply section 33 and other air supply circuits such as the axle modulators 30 and 40 . Therefore, even if an abnormality occurs in one or both of the safety air supply unit 33 and the other air supply circuit, or an abnormality occurs in the second EBSECU 15B, air is supplied to the brake chamber 50 to operate the brake. be able to. Therefore, the redundancy of the pneumatic brake system can be enhanced. Moreover, since the safety air supply unit 33 and the shuttle valve 34 are provided for each wheel, the responsiveness of brake control in an emergency can be improved.

(2) The safety brake valve 71 controlled by the traction ECU 11 supplies air from the suspension tank 28 to the brake chamber 50 in a non-energized state. Also, the shuttle valve 34 allows air to be supplied from the safety brake valve 71 side to the brake chamber 50 side. Therefore, even if an abnormality occurs in the traction ECU 11, the brake can be forcibly operated.

(3) Since the second EBSECU 15B is controlled based on the braking request of the traction ECU 11, the vehicle 100 can be driven even if the first EBSECU 15A malfunctions. Therefore, the redundancy of the pneumatic brake system 10 can be enhanced.

(4) The brake is forcibly operated when an abnormality occurs in the first EBSECU 15A and the traction ECU 11 even if the second EBSECU 15B does not have an abnormality. Therefore, the redundancy of the pneumatic brake system 10 can be enhanced.

(5) Since the amount of air supplied to the brake chamber 50 is changed by the load sensing valve 72 according to the load of the vehicle 100, the braking force can be increased when the load is large. In addition, the load sensing valve 72 communicates with the air suspension system and changes the amount of air supply according to the air pressure of the air suspension system. Braking force can be changed mechanically. In addition, the braking force can be adjusted so as not to collide with the vehicle in front.

It should be noted that the above-described embodiment can be modified as appropriate and implemented as follows.
The suspension tank 28 is used as an air supply source for the safety air supply unit 33 and the safety brake valve 71, but the air storage tank 21 or other tanks may be used.

- In the above embodiment, the load sensing valve 72 communicating with the suspension system is provided, but if the feedback control of the braking force can be executed based on the vehicle speed acquired from the vehicle speed sensor 53, this may be omitted. Alternatively, the towing ECU 11 may acquire a load value from a load sensor that detects the load, and output a deceleration request to the second EBSECU 15B based on the load value. Alternatively, the second EBSECU 15B may acquire the load value directly from the load sensor.

- In the above-described embodiment, when an abnormality occurs in one of the first EBSECU 15A and the traction ECU 11, the traction ECU 11 that operates normally causes the forced braking to be actuated. Alternatively, the second EBSECU 15B may perform brake control based on a deceleration request from the traction ECU 11 that operates normally. Alternatively, the second EBSECU 15B may operate the brake so that the vehicle 100 runs at a predetermined speed (for example, 20 km/h).

In the above embodiment, the second EBSECU 15B reduces the speed to, for example, 20 km/h when an abnormality occurs in the first EBSECU 15A, but the brake may be applied to stop the vehicle 100. Further, when an abnormality occurs in the first EBSECU 15A, the second EBSECU 15B may perform the same control as the first EBSECU 15A, i.e., control the brakes in response to the deceleration request of the traction ECU 11, and allow the vehicle 100 to run.

- In the above embodiment, normal brake control is performed even when an abnormality occurs in the second EBSECU 15B (state 210). Alternatively, when an abnormality occurs in the second EBSECU 15B, the first EBSECU 15A may decelerate. By doing so, the vehicle can be gently stopped even when an abnormality occurs in the first EBSECU 15A or the like.

- In the above-described embodiment, the pneumatic brake system 10 includes the safety brake valve 71 for activating the forced brake. may be omitted.

- The pneumatic brake system 10 only needs to include at least the second EBSECU 15B and the safety modulators 32L, 32R, 42L, 42R, and other configurations can be changed as appropriate.

- In the above-described embodiment, the safety modulators 32L, 32R, 42L, and 42R are provided corresponding to the respective wheels. Alternatively, a security modulator may be associated with at least one wheel. Alternatively, security modulators may be provided for both wheels of one axle. Alternatively, a security modulator may be associated with at least one drive wheel.

- In the said embodiment, the structure of security modulator 32L, 32R, 42L, 42R was made the same. Alternatively, the configuration of the front wheel security modulators 32L, 32R may be different from the configuration of the rear wheel security modulators 42L, 42R. Also, the configuration of the security module may be different between the left wheel and the right wheel.

In the above embodiment, the pneumatic brake system 10 has been described as a brake system for the vehicle 100 that runs in a row, but it may be installed in a brake system for a vehicle that runs alone without running in a row.

- In the above-described embodiment, the vehicle 100 has the rear wheels 52 as the driving wheels, but the front wheels 51 may be the driving wheels. Further, in the above embodiment, the pneumatic brake system 10 is described as being mounted on a cargo vehicle having a cargo bed. Alternatively, the air supply system may be installed in other vehicles such as a passenger car, an articulated vehicle in which a trailer is coupled to a tractor, and a railroad vehicle.

10 Pneumatic brake system 11 Traction ECU 11A First traction ECU as main control device 11B Second traction ECU as main control device 15A First EBSECU as brake control device 15B Safety brake 2nd EBS ECU as a control device 19... In-vehicle network 20... ECU 21... Air storage tank 22... Compressor 23... Air dryer 24... Protection valve 25... Parking brake tank 26... Rear wheel brake tank, 27 Front wheel brake tank 28 Suspension tank as air supply source 30, 40 Axle modulator 31 Brake valve 31A Front wheel controller 31B Rear wheel controller 32L, 32R, 42L , 42R... security modulator, 33... security air supply unit, 34... shuttle valve, 36... ABS valve, 50... brake chamber as brake mechanism, 53... vehicle speed sensor, 54... pressure sensor, 55... parking brake control valve, 56 parking brake relay valve 60 to 63 supply path 65 signal supply path 66 tank side supply path 70 forced brake modulator 71 safety brake valve as a forced brake solenoid valve 72 valve device 100...vehicle, 100a...leading vehicle, 100b...following vehicle.

Claims (6)

A pneumatic brake system that supplies air to a brake mechanism of a vehicle to operate the brake and discharges air from the brake mechanism to release the brake,
a safety air supply section controlled by a second control device to supply air to the brake mechanism;
and a direction switching unit connected to a brake air supply circuit that is controlled by a first control device and supplies air to the brake mechanism through a path different from that of the safety air supply unit. prepared,
the direction switching unit allows air to flow only in a direction from the high pressure side of the safety air supply unit and the brake air supply circuit toward the brake mechanism;
When an abnormality occurs in the brake air supply circuit, air is supplied to the brake mechanism by the safety air supply unit to decelerate the vehicle to a predetermined speed and to run while maintaining the speed.
pneumatic brake system. Equipped with a forced brake solenoid valve controlled by the main controller,
2. The pneumatic brake system according to claim 1, wherein a forced brake is actuated when an abnormality occurs in said second control device while said vehicle is running while maintaining said decelerated speed. Equipped with a forced brake solenoid valve controlled by the main controller,
2. The pneumatic brake system according to claim 1, wherein, while the vehicle is running while maintaining the decelerated speed, a forced brake is actuated according to a state in which an abnormality has occurred in the main controller. 2. The second control device according to claim 1, wherein the second control device further decelerates the vehicle to a predetermined speed based on information obtained from a sensor that detects the load of the vehicle, and causes the vehicle to run while maintaining that speed. pneumatic brake system. a forced brake solenoid valve controlled by a main controller that outputs a braking request to the second controller that controls the safety air supply unit;
The forced brake solenoid valve cuts off the supply of air from an air supply source that stores compressed air to the brake mechanism side in an energized state energized by the main control device, and cuts off the supply of air to the brake mechanism side in a non-energized state. supplying air from a supply source to the brake mechanism side;
2. The pneumatic brake system according to claim 1, wherein when air is supplied from the forced brake solenoid valve, the direction switching section allows air to be supplied from the forced brake solenoid valve side to the brake mechanism side. . An air-driven suspension system is communicated between the forced brake solenoid valve and the safety air supply unit so that the amount of air supplied to the brake mechanism increases as the load of the vehicle increases. 6. A pneumatic brake system as claimed in claim 5 , wherein a valve arrangement is provided to change to .

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