JPH0443414Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is provided in vehicles, etc., and when supplying pressurized air from a working air source to a brake system line and an auxiliary equipment line, The present invention relates to a working air supply device that guarantees the supply of pressurized air to brake system lines even if air leakage occurs.

[Prior Art] Conventionally, in a vehicle such as a truck, as shown in FIG.
Pressurized air is introduced into the chamber and the pressure is accumulated. The pressurized air stored in the air tank b is supplied to the brakes and various auxiliary equipment via the brake system line d and the auxiliary equipment line e, which have a dedicated brake system tank c, and is sequentially consumed. It is becoming more and more like this. Examples of auxiliary equipment include:
There are a cylinder f for controlling the variable displacement supercharger, a cylinder g for controlling the variable swirl device, a cylinder h for controlling the exhaust brake, and an air horn i, etc., and at the inlets of these auxiliary machines f to i, Solenoid valves j and k are provided to control the introduction of pressurized air from the auxiliary system line e. In particular, the operation of the variable capacity supercharger and the variable swirl device is controlled by a controller n that processes detection signals from sensors l and m that detect the engine load L and the engine rotation speed R. , solenoid valves j of control cylinders f and g that control these superchargers and devices are configured to have their opening degrees controlled by output signals from a controller n.

Furthermore, the air tank c is provided with an internal pressure P to the driver.
The tank is equipped with a pressure gauge q, a minimum pressure detection switch r, and an alarm light s that detect and issue an alarm when the tank internal pressure P falls below the required pressure.

In such a working air supply system, it is extremely important to supply pressurized air to the brake system line d, and generally two systems are provided with tanks c exclusively for the brake system, one of which is A safety design is provided so that even if tank c becomes unable to supply pressurized air, backup can be performed with the other tank c.

[Problems to be solved by the invention] Conventionally, the brake system line d and the auxiliary equipment line e, which have a dedicated brake system tank c, are connected together to a single air tank b. Therefore, if the auxiliary system line e is damaged and air leaks, both the pressurized air stored in the air tank b and the pressurized air introduced from the air compressor into the air tank b will be transferred to the auxiliary system line e. As a result, the pressure in the air tank c decreases and the dedicated tank c for the brake system line d
It was not possible to supply pressurized air to the On the other hand, pressurized air from the special tank c, which had accumulated a certain amount of pressure, would flow back into the air tank b, and the pressurized air in the brake system line d would also flow out from the damaged part of the auxiliary system line e. .

Conventionally, to deal with such situations,
A check valve t is provided on the inlet side of the dedicated tank c,
This prevents the pressurized air that has already been pressurized from flowing out to the auxiliary system line e.

However, although it is possible to prevent the leakage of the pressurized air that has already been accumulated, it is not possible to expect pressurized air to be supplied from air tank B to dedicated tank C from now on, and each time the brake is used, the pressure in dedicated tank C is increased. The amount of air decreased, eventually causing problems with brake operation. In this case, the driver is alerted to the emergency by an audible alarm before the pressure in the special tank c reaches a level that would interfere with brake operation, but in any case, the driver is unable to continue driving after that. Nakatsuta.

A related technology is the ``air brake piping circuit'' (opened in 1973), in which a valve is installed in the auxiliary equipment line that branches from the brake system line, and the valve is opened and closed according to the brake system line pressure. −128165
Publication No.) and “Compressed air supply circuit for vehicle braking”
(Utility Model Application Publication No. 56-131259) has been proposed.
In the case of the "air brake piping circuit" and the "vehicle braking compressed air supply circuit", by replacing the safety valve with a valve that closes the auxiliary system line in response to a decrease in brake system line pressure, the auxiliary equipment system If the brake system line pressure decreases due to air leakage in the line, by closing the auxiliary equipment line, pressurized air can be continuously supplied from the air compressor to the brake system line, allowing the brake to operate. can be guaranteed. However, the valve adopted in the above proposal is operated based on the pressure state of the brake system line, so when the brake system line pressure suddenly decreases due to damage to the auxiliary equipment line, it closes and closes the brake system line. When the pressure is restored, it opens again and operates to supply pressurized air to the auxiliary equipment line. The opening/closing operation of such valves is basically to ensure air supply to the brake system line when the pressure in the brake system line decreases due to frequent use of the brakes on downhill roads during normal driving. The only premise is that the air supply to the auxiliary system line will be resumed after the line pressure is restored.

However, if we consider the case where the auxiliary system line is damaged and assumes that the valve operates in this way, the pressurized air supplied to the auxiliary system line mentioned above will leak and the valve will be closed again, resulting in the valve being closed frequently. It will be opened and closed repeatedly. If the auxiliary equipment line is equipped with auxiliary equipment for engine control, such as a variable displacement supercharger or a control cylinder for a swirl control device, the frequent opening and closing of valves may cause problems in the supply of pressurized air. Therefore, the supply of the engine is stopped without being controlled by the controller, and there is a risk that the engine control will be disturbed and safe driving will be hindered.

For example, in a variable capacity supercharger, the boost pressure is changed by solenoid valve control, but due to malfunction of the solenoid valve, the boost pressure is not properly controlled, and the output increases or decreases, causing the driver's intention to change. Regardless of the situation, the vehicle may accelerate or decelerate, which will have a negative impact on safety.

[Means for Solving the Problems] The present invention includes a pressure detection means for detecting the pressure of an operating air source to which a brake system line and an auxiliary system line having an on-off valve are connected and supplies pressurized air to these lines; and control means for closing the on-off valve when the number of times the pressure detected by the pressure detection means has decreased below the set pressure exceeds the set number of times.

[Function] Describing the function of the present invention, damage to the auxiliary system line is estimated based on the number of times that the pressure of the working air source detected by the pressure detection means has decreased below the set pressure exceeds the set number of times, Based on this estimation, the control means maintains the on-off valve of the auxiliary system line in a closed state. In other words, this control closes the auxiliary system line in response to a pressure drop in the working air source that occasionally occurs during normal driving, ensures control to supply pressurized air to the auxiliary system line again after the pressure is restored, and then starts the auxiliary system line. In the event of an emergency due to damage to a machine line, valve opening and closing operations, which can occur frequently and continuously, are forcibly closed to eliminate the adverse effects of auxiliary machinery on engine control, etc.

[Embodiment] A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in Fig. 1, reference numeral 1 denotes an air tank which is a working air source, and into this air tank 1, air is used to introduce pressurized air from an air compressor via a check valve 2 to prevent backflow. Supply line 3 is connected. Further, a pressure detection line 4 is connected to this air tank 1 to derive its internal pressure P and supply it to an air governor, and the air governor detects air based on the tank internal pressure P introduced via this line 4. The compressor is controlled to introduce a predetermined amount of pressurized air into the air tank 1 and to accumulate pressure therein. Furthermore, this air tank 1 is provided with a low pressure switch 5, which is pressure detection means and is turned on in response to the internal pressure P falling below a set pressure _P0 . This low pressure switch 5 is kept OFF when the tank internal pressure P is equal to or higher than the set pressure _P0 .

A brake system line 6 and an auxiliary equipment system line 7 are connected as air consumption systems to the air tank 1 configured as described above and in which pressurized air is stored. Two brake system lines 6 are installed, and each line 6 is provided with a brake system dedicated tank 8, and at the inlet side of these dedicated tanks 8, there is a backflow of the accumulated air to the air tank 1. A check valve 9 is provided to prevent this.

On the other hand, the auxiliary system line 7 is composed of a main line 10 and branch lines 11 that are independently branched from the main line 10, and auxiliary machines are connected to each branch line 11 independently. In this embodiment, the auxiliary machines include a variable capacity supercharger, a variable swirl device, and cylinders 12, 13 for exhaust brake control.
14 and air horn 15 are illustrated.
Further, each branch line 11 is provided with electromagnetic valves 16 and 17, which are on-off valves for adjusting the amount of supplied air.

The solenoid valves 16 and 17 of the auxiliary system line 7 configured as described above, especially the solenoid valves 16 for the control cylinders 12 and 13 of the variable displacement supercharger and the variable swirl device involved in the automatic control of the engine. is connected to a control unit 18 which is a control means for controlling the opening degree. A load sensor 19 and a rotation speed sensor 20 for detecting the engine operating state are connected to the control unit 18, and the engine load L and engine rotation speed R are inputted from these sensors 19 and 20, respectively. . Although not shown, as the contents of manual operations corresponding to the engine operating state, gear neutral signals, clutch intermittent signals, accelerator depression signals, etc. are input to the control unit 18 from the neutral switch, clutch switch, and accelerator switch, respectively. It is becoming more and more like this. In particular, the above-mentioned low pressure switch 5 is connected to this control unit 18, and the tank internal pressure P of the air tank 1 is input as an ON-OFF signal. To briefly describe the functions of this control unit 18, it controls the accumulation of pressurized air in the air tank 1 when the engine is started, and controls the opening of the solenoid valve 16 according to the engine condition during normal operation. Control of the variable capacity supercharger and variable swirl device, and the signal from the low pressure switch 5,
When the number of times n in which the pressure P in the air tank 1 has decreased below the set pressure P ₀ exceeds the set number N, an emergency situation (air leakage due to damage to the auxiliary equipment line 7, etc.) is assumed, and the solenoid valve 16 is activated. Control is now in place to forcibly close the valve. For control, when the internal pressure P of the air tank 1 detected by the low pressure switch 5 falls below the set pressure _P0 , the solenoid valve 16
Control is also performed to forcibly close the terminal for a set time Td.

The control of the above control unit 18 is
This will be explained according to FIG.

In the figure, part A is control during startup, part B is control during normal operation, and part C is control during emergency.

Starting control A requires a considerable amount of time to increase the pressure in the air tank 1 when starting the engine, so the set time
The solenoid valve 16 is not particularly controlled during Ta (approximately 3 minutes). To explain according to the flow, when the key switch is turned on, the control values n, t ₁ ~
Set _t3 to 0 to give an initial value. Here, n
is the number of times the tank internal pressure P falls below the set pressure P ₀ , t ₁ ~
_t3 is a time value for control. Turn on the key switch
, a timer within control unit 18 is started. First, time t ₁ is added (t ₁ = t ₁ + 1)
Until the time _t1 exceeds the set time Ta, the normal operation control B is not entered, and pressurized air is mainly stored in the air tank 1. However, even during this period, the brake system line 6 and auxiliary equipment (for example, the air horn 15) that have a solenoid valve 17 that is operated as appropriate independent of the control unit 18 may be supplied with air as necessary. Pressurized air will be supplied from tank 1.

When the start-up control A is finished, the normal operation control B is normally performed. This control B includes various detected values (engine load L, engine speed R, tank internal pressure P, etc.)
It is performed on the assumption that the tank internal pressure P is higher than the set pressure _P0 , and mainly consists of a control part for maintaining the idling state, a control part for changing gears, and a control part for normal driving. In the control section, if the neutral switch is OFF (the gear is engaged) and the clutch switch is ON (the clutch pedal is released), the engine power is transmitted to the drive wheels. , based on the engine load L and engine speed R output from each sensor 19, 20 corresponding to the engine operating state.
The solenoid valve 16 is controlled according to a map etc. stored in the unit 18. As a result, control of the variable capacity supercharger or the like according to the engine state can be achieved.

Regarding the control part during gear change, since the engine load and engine speed change during gear change, if the control is performed accordingly, the solenoid valve 16 will be opened and closed frequently, and this will cause the solenoid valve 16 and control cylinder 12 to change. , 13, etc., the electromagnetic valve 16 is maintained in the state immediately before the gear change. This control part has a neutral switch that corresponds to the manual operation of the gear change.
OFF and the clutch switch is OFF (the clutch pedal is depressed), or if the neutral switch is ON (the gear is in a neutral state) and the clutch switch is OFF, then the accelerator switch is It will be executed on the condition that the accelerator pedal is off (the accelerator pedal is removed).

Furthermore, the control part for maintaining the idling state is undesirable because if the idling state is maintained for a long time, the pressure in the air tank 1 will be kept high and a considerable pressure will act on the solenoid valve 16.
The solenoid valve 16 is forcibly closed.
This control part is turned on when the neutral switch is turned on.
If the clutch switch is ON, the solenoid valve 16 is closed in response to the time _t1 exceeding the set time Tb. This time t ₁ is
For example, when this control section continues from start-up control A, a considerable amount of pressurized air has already been accumulated in air tank 1, so time t ₁ is assumed to be not 0 and is immediately compared with set time Tb. . On the other hand, once the solenoid valve 16 is closed, the time t ₁ is set to 0 for the next control, so in that case, the time t ₁ is changed from the time when the idling state is entered.
is calculated by a timer and compared with the set time Tb.

Emergency control C for these controls A and B is performed as follows. In this emergency control C, the number of times n that the tank internal pressure P has fallen below the set pressure _P0 exceeds the set number N (for example, about 3 to 4 times) within the set time Tc (for example, about 5 to 6 minutes). By this,
After determining air leakage, the solenoid valve 16 is forcibly maintained in a closed state. This is because the tank internal pressure P falls below the set pressure P ₀ several times during engine operation, such as when draining the air tank 1 or when using the brakes when going downhill, and when the tank internal pressure P drops below the set pressure P 0 many times during emergency situations. Taking into consideration the situation in which the internal pressure P decreases, the configuration is such that an emergency state is estimated when the number of times n of pressure decreases exceeds a set number N within a certain period of time Tc.

Also, in this control C, the tank internal pressure P is the set pressure.
When the solenoid valve 16 is closed in response to P being lower than P ₀ , the tank internal pressure P immediately drops to the set pressure P ₀ .
If the cycle time in which the solenoid valve 16 is opened again due to exceeding the limit is extremely short, the following problems will occur. Contains control parts to maintain. The problem is that even if the solenoid valve 16 is closed after the set number of times N has been exceeded, the solenoid valve 16 will be repeatedly opened and closed until then. If this is repeated in extremely short cycles, the control of the control cylinders 12 and 13 controlled by the solenoid valve 16 may go out of order, which may destabilize engine control and impede safe driving. In this regard, by closing the solenoid valve 16 for the set time Td, the cycle time can be made gentle and severe disturbances in the engine can be prevented. Additionally, as a malfunction, if the internal pressure of the air tank 1 cannot be raised in a short time due to the consumption of a large amount of pressurized air due to the use of the brakes on a long downhill road, etc., the number of times the solenoid valve 16 is opened and closed even though it is not an emergency situation. There are cases where the solenoid valve 16 is forcibly closed when the number of times exceeds the set number. On the other hand, by giving a set time Td to ensure a period for the air tank internal pressure P to rise,
Malfunctions in such cases can also be prevented.

The process will be explained below according to the flow.

First, when it is determined for the first time that the internal pressure P of the air tank 1 has fallen below the set pressure _P0 , this first
Since the time t ₃ is 0 at the time, the timer starts counting the time t ₃ from that point. Next, a comparison is made between this time _t3 and the set time Tc, and the set time
If it is within Tc, the number n of times the tank internal pressure P decreases is added (n=1 for the first time). Next, this number of times n and a set number of times N are compared, and if the number of times is less than the set number of times N, the process moves to the next control.

In this control, by adding time t ₂ , solenoid valve 1 is operated until time t ₂ reaches set time Td.
6 to extend cycle time. After that, the control returns to "read detected value". The returned control is normally shifted to the normal operation control B due to an increase in the tank internal pressure P, but when a decrease in the internal pressure P is detected again, the returned control is shifted to the emergency control C for the second time. At this time, since the time _t3 has already been counted, this time _t3 is compared with the set time Tc, and if it is within the set time Tc, the number n is added. here,
If the second time _t3 exceeds the set time Tc, the previous control values n, _t3 are reset,
This second time is treated as the first time, and time _t3 is also counted again.

Such control is repeated until the set time Tc
If the number of times n exceeds the set number of times N within that period, the electromagnetic valve 16 will be forcibly closed from now on as it is considered to be an emergency air leak situation.

With the above configuration, the control of the solenoid valve 16 in normal operating conditions is not impaired, and the adverse effect on safe driving caused by the repeated opening and closing of the solenoid valve 16 is eliminated, and the It is possible to ensure the supply of pressurized air to the brake system line 6 during operation, and to guarantee running safety.

Note that the above-mentioned set times Ta, Tc, Td and the set number of times N are design matters, and it goes without saying that any value may be set.

Incidentally, FIG. 3 shows a modification of the above embodiment. By newly installing a solenoid valve 21 controlled by the control unit 18 at the connection between the air tank 1 and the auxiliary system line 7, it is closed when the air tank internal pressure P is extremely low, and then the control unit 18 closes it. An auxiliary machine having a solenoid valve 17 other than the closed solenoid valve 16 (for example, an air horn 1
5) may be controlled by this electromagnetic valve 21.

In addition, in FIG. 1 and FIG. 3, 22 and 23 are a pressure gauge and a warning light, respectively.

[Effects of the Invention] In summary, the present invention provides the following excellent effects.

A pressure detection means for detecting the pressure of a working air source to which a brake system line and an auxiliary equipment line having an on-off valve are connected and supplies pressurized air to these lines; Equipped with a control means that closes the on-off valve when the number of times exceeds a set number, it is possible to accurately estimate an emergency situation and prevent engine control disturbances due to malfunction of the solenoid valve, while also appropriately controlling the brake system line. The supply of pressurized air can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a preferred embodiment of the present invention;
FIG. 2 is a flowchart showing control details, FIG. 3 is a system diagram showing a modified example, and FIG. 4 is a system diagram showing a conventional example. In the figure, 1 is an air tank that is a working air source, 5 is a low pressure switch that is a pressure detection means, 6 is a brake system line, 7 is an auxiliary system line, 16 is a solenoid valve that is an on-off valve, and 18 is a control unit that is a control means. It is.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Pressure detection means for detecting the pressure of a working air source to which a brake system line and an auxiliary system line having an on-off valve are connected and supplies pressurized air to these lines;
A working air supply device comprising: control means for closing the on-off valve when the number of times the pressure detected by the pressure detection means has decreased below the set pressure exceeds a set number of times. (2) The operating air according to claim 1, wherein the control means closes the on-off valve for a set time in response to the pressure detected by the pressure detection means falling below the set pressure. Feeding device.