JP4506636B2 - Negative pressure supply device for vehicle - Google Patents

Description

  The present invention relates to a vehicle negative pressure supply device that supplies negative pressure to a negative pressure operating device mounted on a vehicle.

  Conventionally, a vehicle has been equipped with a device that operates using negative pressure as a drive source. As a typical example, there is a brake booster for reducing a brake pedal depression force by a vehicle driver. is there.

The negative pressure to the negative pressure operating device such as a brake booster is supplied from an intake passage of an engine (internal combustion engine) in a general gasoline engine vehicle.
As a specific configuration, first, the intake pipe forming the intake passage of the engine, electrically opening controllable ISC (idle speed control) inhalation such as valves or electronic throttle valve air volume of regulatory valve provided It is and negative pressure supply path is provided between the downstream side of the regulatory valve, a negative pressure input of the negative pressure motive device. The electronic throttle valve is a throttle valve whose opening is adjusted by an electric actuator such as a step motor.

Then, the opening degree of the regulatory valve (ISC valve or electronic throttle valve), when in the idle control request, by a known idle control, is controlled so that the engine speed becomes the idle speed of the target that is, in particular, the engine speed is a normal idle speed (i.e., idle speed on engine design) when the opening degree of the regulatory valve is throttled so that, the regulatory valve in the intake pipe Further, a negative pressure (so-called intake pipe negative pressure) is generated further downstream, and the negative pressure is supplied to the negative pressure input unit of the negative pressure operating device via the negative pressure supply path.

On the other hand, in the vehicle, the idle control, such as when the load on the engine by the operation of the air conditioner device or the like or increase, large electric load of the power consumption increases the power generation amount by the power generation device operates, the regulatory valve Idle-up is performed to increase the engine speed and engine output by increasing the opening degree compared to normal idling. When by such idle-up opening degree of the regulatory valve increases, negative pressure is not generated in the intake pipe, as a result, it becomes impossible to supply a sufficient negative pressure in the negative pressure motive device.

Therefore, there is a technique for installing a negative pressure pump separately and supplementing the negative pressure with the negative pressure pump.
Furthermore, Patent Document 1 describes a concept of supplying negative pressure to a negative pressure operating device by using intake pipe negative pressure when an abnormality occurs in the negative pressure pump.
Japanese Patent Laid-Open No. 10-54286

  Here, when the technique of Patent Document 1 is considered, when an abnormality occurs in the negative pressure pump, idle-up by idle control (that is, the opening of the ISC valve or electronic throttle valve is set to the opening at the time of normal idling). It is conceivable that the negative pressure is reliably supplied from the intake pipe of the engine to the negative pressure operating device.

  However, simply prohibiting idling up will cause the engine to endure without being able to withstand the load (engine stall), or the power generation amount of the power generator driven by the engine will be insufficient and the battery will go up, There is concern about the occurrence of this problem.

  The present invention has been made in view of these problems, and even when an abnormality occurs in the negative pressure pump, negative pressure can be reliably supplied to the negative pressure operating device, and other problems such as engine stall and battery exhaustion are also caused. The object is to provide an avoidable negative pressure supply device.

In order to achieve the above object, a negative pressure supply device for a vehicle according to the present invention includes a negative pressure pump that supplies negative pressure to a negative pressure input unit of a negative pressure operating device that operates using negative pressure as a drive source, and a negative pressure pump thereof. An abnormality detection means for detecting an abnormality of the pressure pump, an adjustment valve provided in an intake passage of the internal combustion engine mounted on the vehicle for adjusting the intake air amount of the internal combustion engine, and an internal combustion engine when an idle control is requested of such rotational speed becomes the idle speed of the target, and an idle control means for controlling the opening of the regulatory valve. Further, the downstream side of the control valve in the intake passage of the internal combustion engine and the negative pressure input portion of the negative pressure operating device are connected by a connection path. Furthermore, negative pressure determination means for determining whether or not the negative pressure supplied to the negative pressure operating device has reached a specified value is provided.

In the vehicle negative pressure supply device of the present invention, the abnormality detection unit detects an abnormality of the negative pressure pump, and the idle control is being requested . Further, the negative pressure determination unit detects the negative pressure of the negative pressure operating device. If it is determined not to reach the specified value, and operating the vacuum retention means, by prohibiting to be larger than a predetermined opening the opening of the regulatory valve idling control means, the downstream The negative pressure is supplied to the negative pressure input unit of the negative pressure operating device via the connection path (specifically, downstream of the control valve in the intake passage).

Further, when the negative pressure securing means operates, the reducing means performs power consumption reduction processing for reducing power consumption in the vehicle.

In other words, the negative pressure supply apparatus for a vehicle of the present invention, when an abnormality occurs in the negative pressure pump is idle control idle control means when in the request is the opening of the regulatory valve in an attempt to idle up the predetermined opening By prohibiting the pressure from exceeding the degree, the negative pressure is surely supplied from the intake passage of the internal combustion engine to the negative pressure operating device. there because there is a possibility of causing battery exhaustion due to normal power generation shortage lowered than idle speed, to prevent the occurrence of dead battery by performing power consumption reduction process to reduce the power consumption in the vehicle.

Therefore, according to this negative pressure supply device for a vehicle, even when an abnormality occurs in the negative pressure pump, negative pressure can be reliably supplied from the intake path of the internal combustion engine to the negative pressure operating device, and the battery can be prevented from rising. can do.

If there is a possibility of causing engine stall due to the above-mentioned prohibition , as described in claim 3, when the negative pressure securing means is operated, the reduction means is applied to the crankshaft of the internal combustion engine together with the power consumption reduction processing. If load reduction processing for reducing the applied load is also performed, the occurrence of engine stall can be prevented.
Further, the negative pressure pump may be configured to always operate in a normal state, but when it is detected that the negative pressure supplied to the negative pressure operating device does not reach a predetermined required value. It is preferably configured to operate. This is because the operation of the negative pressure pump can be minimized.

  The vehicle negative pressure supply device of the present invention can be applied not only to an ordinary vehicle having only an internal combustion engine as a power source, but also to a hybrid vehicle having an internal combustion engine and an electric motor.

Here, in the negative pressure supply device for a vehicle according to the present invention, the negative pressure securing means and the reducing means do not operate when the negative pressure determining means determines that the negative pressure has reached the specified value. It has become .

In other words, the negative pressure securing means and the reducing means are that the abnormality detecting means detects an abnormality of the negative pressure pump and is requesting idle control, and the negative pressure determining means determines that the negative pressure of the negative pressure operating device is a specified value. It is activated when it is determined that the value has not been reached .

For this reason , the opportunity for the negative pressure securing means and the reducing means to operate can be minimized .

Moreover, the negative pressure supply apparatus for a vehicle of the present invention, reduction means, as power reduction process, the operation of the radiator fan is prevented or inhibited to the extent that does not lead to overheating of the internal combustion engine, implementing the process of. The radiator fan is an electric fan that blows air to the radiator of the internal combustion engine.

  Then, as a method of suppressing the operation of the radiator fan in a range that does not cause overheating of the internal combustion engine, a method of reducing the rotation speed of the radiator fan until the cooling water temperature of the internal combustion engine rises to a predetermined value lower than the overheat value. Alternatively, a method may be considered in which the cooling water temperature threshold value of the internal combustion engine at which the radiator fan starts operating is changed to a value higher than the normal value (<overheat value).

  Further, as a method of prohibiting the operation of the radiator fan within a range that does not cause overheating of the internal combustion engine, the radiator fan is operated intermittently until the cooling water temperature of the internal combustion engine rises to a predetermined value lower than the overheating value (constant A method of stopping time by time) is conceivable.

By the way, if the reduction means performs the load reduction process, the load reduction process includes, for example, a process of prohibiting the compressor of the air conditioner from being driven by the crankshaft of the internal combustion engine.
  Further, as the load reduction process, for example, there is a process of suppressing or prohibiting power generation of a power generation device driven by a crankshaft of an internal combustion engine.
  As a method for suppressing power generation by the power generation device, for example, there is a method of reducing a field current (current flowing through the field coil) in an alternator as the power generation device. Further, as a method for prohibiting power generation by the power generation device, there is a method of cutting a field current. And if the power generation of a power generator is suppressed or prohibited, the load applied to the crankshaft to drive the power generator will be reduced.

  A vehicle negative pressure supply device according to an embodiment to which the present invention is applied will be described below. The vehicle negative pressure supply device according to the present embodiment supplies negative pressure to a brake booster as an example of a negative pressure operating device in a vehicle equipped with a gasoline engine as an internal combustion engine.

First, FIG. 1 is a configuration diagram illustrating a vehicle negative pressure supply device according to a first embodiment.
As shown in FIG. 1, a throttle valve 5 is provided in the intake pipe 3 of the engine 1. The opening of the throttle valve 5 changes mechanically according to the amount of accelerator operation by the vehicle driver.

  The intake pipe 3 is provided with a bypass passage 7 for bypassing the throttle valve 5, and the bypass passage 7 is provided with an ISC valve 9 whose opening degree can be electrically controlled. The ISC valve 9 is controlled by an electronic control unit (hereinafter referred to as ECU) 11.

Furthermore, the downstream side of the intake pipe 3 with respect to the throttle valve 5 and the ISC valve 9 and the negative pressure input portion 14 of the brake booster 13 are connected by a connection path 15.
When the idle control is being requested, the opening of the ISC valve 9 is controlled by well-known idle control by the ECU 11 so that the engine speed (the engine 1 speed) becomes the target idle speed. When the opening of the ISC valve 9 is throttled so that the engine speed becomes the normal idle speed (that is, the idle speed designed in the engine 1), the throttle valve 5 and the ISC valve of the intake pipe 3 A negative pressure (so-called intake pipe negative pressure) is generated downstream of 9, and the negative pressure is supplied to the negative pressure input unit 14 of the brake booster 13 via the connection path 15. The case where the idle control is being requested is a case where a condition for performing the idle control is satisfied. For example, the condition is satisfied when the accelerator operation amount by the vehicle driver is zero, for example.

  The negative pressure input unit 14 of the brake booster 13 is connected to an electric negative pressure pump 17 controlled by the ECU 11. The negative pressure pump 17 includes a motor and generates negative pressure by the rotation of the motor. When the negative pressure pump 17 is operated, negative pressure is supplied to the negative pressure input unit 14 of the brake booster 13 regardless of the intake pipe negative pressure.

  Furthermore, the brake booster 13 is provided with a negative pressure sensor 19 that detects the negative pressure supplied to the brake booster 13, and a detection signal from the negative pressure sensor 19 is input to the ECU 11. Is done.

  On the other hand, an abnormality detection sensor for detecting an abnormality of the negative pressure pump 17 is attached to the negative pressure pump 17, and a detection signal from the abnormality detection sensor is also input to the ECU 11. The abnormality detection sensor outputs, for example, a detection signal indicating the occurrence of an abnormality when detecting an event that the motor of the negative pressure pump 17 is energized but the motor does not rotate.

  Further, the ECU 11 detects an operating state of the engine 1 such as an accelerator sensor 21 that detects an accelerator operation amount, a rotation sensor 23 that detects an engine speed, and a water temperature sensor 25 that detects a cooling water temperature of the engine 1. Signals from various sensors are also input.

  Furthermore, an air conditioner device 27 for the vehicle, a radiator fan 29, and a power generator 31 are connected to the ECU 11. The power generator 31 is an alternator driven by a crankshaft (not shown) of the engine 1, and the battery 33 of the vehicle is charged by the power generator 31. Further, electric power is supplied from the battery 33 or the power generation device 31 to each device of the vehicle such as the ECU 11 and the negative pressure pump 17.

  Next, processing executed by the ECU 11 will be described with reference to FIGS. In addition, the process demonstrated below is actually performed by the microcomputer (illustration omitted) mounted in ECU11.

FIG. 2 is a flowchart showing the idle control process. This idle control process is repeatedly executed at regular time intervals (for example, every 16 ms).
As shown in FIG. 2, when the ECU 11 starts executing the idle control process, it is first determined in S110 whether or not the idle control is being requested based on the signal from the accelerator sensor 21, and if the idle control is not being requested ( S110: NO), the idle control process is terminated as it is. In this case, the opening degree control of the ISC valve 9 is not performed.

  On the other hand, if it is determined in S110 that the idle control is being requested, the process proceeds to S120, and the opening degree of the ISC valve 9 is controlled for well-known idle control. Specifically, the cooling water temperature detected by a signal from the water temperature sensor 25, whether or not the compressor of the air conditioner device 27 is driven by the crankshaft of the engine 1, the power generation amount of the power generator 31 (in other words, The target idle speed is set on the basis of the power consumption in the vehicle) and the ISC valve 9 is set so that the actual engine speed detected by the signal from the rotation sensor 23 becomes the target idle speed. To control the opening degree. Thereafter, the idle control process is temporarily terminated.

  When the target idle speed is set to a normal idle speed (that is, when no idle up is performed), the opening of the ISC valve 9 is a predetermined reference opening (variable in this embodiment). (Minimum value in the range). In this case, negative pressure (intake pipe negative pressure) generated downstream of the throttle valve 5 and the ISC valve 9 in the intake pipe 3 is connected to the negative pressure input portion of the brake booster 13 via the connection path 15. 14.

Next, FIG. 3 is a flowchart showing a pump control process for controlling the negative pressure pump 17. This pump control process is also repeatedly executed at regular time intervals (for example, every 16 ms).
As shown in FIG. 3, when the ECU 11 starts executing the pump control process, first, in S210, based on the signal from the negative pressure sensor 19, the negative pressure supplied to the brake booster 13 is It is determined whether or not a specified value that is considered to be sufficient to reduce the depression force of the brake pedal by the user is reached (that is, whether or not “absolute value of negative pressure ≧ absolute value of specified value”).

  If it is determined that the negative pressure has reached the specified value (S210: NO), this means that the negative pressure is not insufficient, and the pump control is performed as it is without operating the negative pressure pump 17. The process ends.

  On the other hand, if it is determined in S210 that the negative pressure has not reached the specified value (S210: YES), the negative pressure is insufficient. The negative pressure pump 17 is driven by energizing the motor. Further, in S220, whether the negative pressure pump 17 is normal or abnormal is determined based on a signal from an abnormality detection sensor attached to the negative pressure pump 17. The normality / abnormality of the negative pressure pump 17 may be determined based on a signal from the negative pressure sensor 19. That is, if the signal from the negative pressure sensor 19 does not change in accordance with the driving of the negative pressure pump 17 (specifically, it does not change indicating a decrease in pressure), it is determined that an abnormality has occurred in the negative pressure pump 17. can do.

And after said S220, the said pump control process is once complete | finished.
With such a pump control process, the negative pressure pump 17 is driven when the negative pressure of the brake booster 13 does not reach the specified value only by the intake pipe negative pressure.

  Next, FIG. 4 is a flowchart showing idle time processing that is repeatedly executed at regular intervals (for example, every 16 ms) in parallel with the idle control processing of FIG. 2 when the idle control is being requested.

  As shown in FIG. 4, when the ECU 11 starts executing the idling process, first, in S310, it is determined whether an abnormality has occurred in the negative pressure pump 17 with reference to the determination result in S220 in FIG. To do.

  If it is determined that no abnormality has occurred in the negative pressure pump 17 (normal) (S310: NO), the idle time processing is terminated as it is, but if the negative pressure pump 17 has an abnormality. When it determines (S310: YES), it progresses to S320.

  In S320, based on the signal from the negative pressure sensor 19, the negative pressure supplied to the brake booster 13 reaches a specified value that is considered to be sufficient to reduce the depression force of the brake pedal by the vehicle driver. It is determined whether or not. In the present embodiment, the specified values in the determination in S320 are the same as the specified values in the determination in S210, but they may be different values.

  If it is determined that the negative pressure has reached the specified value (S320: NO), this means that the negative pressure is not insufficient, and thus the idling process is terminated, but the negative pressure is specified. If it is determined that the value has not been reached (S320: YES), this means that the negative pressure is insufficient, and thus the process proceeds to S330 in order to secure the negative pressure to the brake booster 13.

  In S330, the opening degree of the ISC valve 9 is prohibited from being controlled to be larger than the predetermined opening degree in S120 of the idle control process. And the predetermined opening which restrict | limits the opening increase of the ISC valve 9 by this S330 is the reference | standard opening mentioned above when idle up is not performed. For this reason, idling up of the engine 1 is prohibited, and intake pipe negative pressure is supplied to the negative pressure input unit 14 of the brake booster 13 via the connection path 15.

Further, in subsequent S340, a load reduction process for reducing the load applied to the crankshaft of the engine 1 and a power consumption reduction process for reducing power consumption in the vehicle are performed.
Specifically, as the load reduction process, a process for prohibiting the operation of the air conditioner device 27, specifically, a process for prohibiting the compressor of the air conditioner device 27 from being driven by the crankshaft of the engine 1 is performed. In this process, energization of the electromagnetic clutch that connects the pulley driven to rotate by the crankshaft and the drive shaft of the compressor is prohibited.

  Furthermore, the process which suppresses the electric power generation of the electric power generating apparatus 31 is performed as a load reduction process. This process is to reduce the field current of the power generator 31. Note that power generation may be prohibited instead of suppressing power generation of the power generation device 31. In this case, the field current of the power generation device 31 may be cut.

  Further, as the power consumption reduction process, a process of suppressing the operation of the radiator fan 29 within a range that does not cause overheating of the engine 1 is performed. This process is to change the cooling water temperature threshold of the engine 1 at which the radiator fan 29 starts to operate to a value higher than the normal value (<overheat value). As another method, for example, the engine 1 Until the cooling water temperature rises to a predetermined value lower than the overheat value, the rotational speed of the radiator fan 29 may be reduced.

  Note that, as the power consumption reduction process, the operation of the radiator fan 29 may be prohibited within a range that does not cause the engine 1 to overheat. In this case, a process of stopping the radiator fan 29 every predetermined time (intermittently operating) until the cooling water temperature of the engine 1 rises to a predetermined value lower than the overheat value can be considered.

As a reference example, if N radiator fans 29 are provided in the vehicle (N is an integer of 2 or more), the power consumption reduction processing is performed by reducing one or more and less than N of the plurality of radiator fans. The process of prohibiting the operation of the radiator fan may be used. For example, if there are two radiator fans 29, the operation of one of them may be prohibited.

Then, after performing the load reduction process and the power consumption reduction process as described above in S340, the idle process is temporarily terminated.
In the negative pressure supply device for a vehicle according to the first embodiment as described above, an abnormality has occurred in the negative pressure pump 17 when an idle control request is being made (S310: YES), and the brake booster 13 is negative. If the pressure does not reach the specified value (S320: YES), it is prohibited that the opening of the ISC valve 9 is controlled to be larger than the predetermined opening in order to idle up in S120 of the idle control process (FIG. 2). This ensures that negative pressure is supplied from the intake pipe 3 of the engine 1 to the brake booster 13 (S330). In that case, the engine speed may be lower than the normal idle speed due to the prohibition in S330, and the battery may run out due to engine stall or power generation shortage. Thus, the occurrence of engine stall is prevented and the power consumption is reduced to prevent the battery from running out (S340).

  Therefore, according to the vehicle negative pressure supply device of the first embodiment, even when an abnormality occurs in the negative pressure pump 17, the negative pressure sufficient for vehicle braking from the intake pipe 3 of the engine 1 to the brake booster 13 is achieved. Can be reliably supplied, and other problems such as engine stall and battery exhaustion can be avoided.

  Further, since the processing of S330 and S3340 in FIG. 4 is performed when the negative pressure of the brake booster 13 has not reached the specified value, the opportunity to perform the processing is minimized. Can do.

In the above-described first embodiment, an abnormality detection sensor supplied with the negative pressure pump 17, and the process of determining the normality / abnormality of the negative pressure pump 17 in S220 of FIG. 3, and S310 of FIG. 4, the abnormality detecting 2, the ISC valve 9 corresponds to the control valve, S120 in FIG. 2 corresponds to the idle control means, S330 in FIG. 4 corresponds to the negative pressure securing means, and S340 in FIG. 4 corresponds to the reduction means. 4 corresponds to the negative pressure determination means.

Next, the negative pressure supply device for a vehicle according to the second embodiment will be described.
As shown in FIG. 5, the vehicle negative pressure supply device of the second embodiment has a bypass passage 7 and an ISC valve 9 in the intake pipe 3 of the engine 1 as compared with the vehicle negative pressure supply device of the first embodiment. Instead, the throttle valve 5 is an electronic throttle valve whose opening degree can be electrically controlled by an actuator 35 formed of a step motor. In other words, in the second embodiment, and corresponds to the throttle valve 5 is regulatory valve.

  For this reason, in the negative pressure supply device for a vehicle according to the second embodiment, when the idle control request is not being made based on the signal from the accelerator sensor 21, the ECU 11 determines the accelerator operation amount and the driving state of other vehicles (for example, Well-known throttle opening control is executed in which the opening of the throttle valve 5 is controlled by driving the actuator 35 according to the engine speed, vehicle speed, slip state of each wheel, and the like.

In S120 in the idle control process of FIG. 2, the opening degree of the throttle valve 5 is controlled so that the engine speed becomes the target idle speed.
Further, in S330 in the idling process of FIG. 4, it is prohibited that the opening degree of the throttle valve 5 is controlled to be larger than the predetermined opening degree in S120 of the idle control process. The predetermined opening degree that restricts the increase in the opening degree of the throttle valve 5 in S330 is the opening degree of the throttle valve 5 when the idle up is not performed in S120 of FIG.

  Therefore, also in the second embodiment, the process of S330 prohibits the engine 1 from being idled up, and the intake pipe negative pressure is supplied to the negative pressure input unit 14 of the brake booster 13 via the connection path 15. It will be. And the effect similar to 1st Embodiment can be acquired.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. .

  For example, the predetermined opening that restricts the increase in the opening of the ISC valve 9 or the throttle valve 5 in S330 of FIG. 4 is not limited to the reference opening when idle up is not performed, and the brake booster 13 can be operated. Any opening that can generate a negative pressure in the intake pipe 3 may be used.

In addition, the vehicle negative pressure supply device of each of the above embodiments can be similarly applied not only to a normal vehicle including only the engine 1 as a power source but also to a hybrid vehicle.
Further, the negative pressure operating device to be supplied with negative pressure is not limited to the brake booster 13 and may be other devices.

It is a lineblock diagram showing the negative pressure supply device for vehicles of a 1st embodiment. It is a flowchart showing an idle control process. It is a flowchart showing a pump control process. It is a flowchart showing the process at the time of idle. It is a block diagram showing the negative pressure supply apparatus for vehicles of 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 3 ... Intake pipe, 5 ... Throttle valve, 7 ... Bypass passage, 9 ... ISC valve, 11 ... ECU, 13 ... Brake booster, 14 ... Negative pressure input part, 15 ... Connection path, 17 ... Negative Pressure pump, 19 ... Negative pressure sensor, 21 ... Accelerator sensor, 23 ... Rotation sensor, 25 ... Water temperature sensor, 27 ... Air conditioner device, 29 ... Radiator fan, 31 ... Power generation device, 33 ... Battery, 35 ... Actuator

Claims (5)

A negative pressure pump that supplies negative pressure to a negative pressure input unit of a negative pressure operating device that operates using negative pressure as a drive source;
An abnormality detecting means for detecting an abnormality of the negative pressure pump;
A control valve provided in an intake passage of an internal combustion engine mounted on a vehicle, for adjusting an intake air amount of the internal combustion engine;
When idle control request, so that the rotational speed of the internal combustion engine is idle speed of the target, and an idle control means for controlling an opening degree of the regulatory valve,
A connection path that connects a downstream side of the control valve in the intake passage and a negative pressure input unit of the negative pressure operating device,
Negative pressure determination means for determining whether or not the negative pressure supplied to the negative pressure operating device has reached a specified value;
Operates when the abnormality of the negative pressure pump is detected by the abnormality detecting means, the idle control is being requested , and further, the negative pressure determining means determines that the negative pressure has not reached a specified value. Te, by prohibiting said idle control means greater than a predetermined opening the opening of the regulatory valve, the negative pressure input of the negative pressure motive unit through the connection path from the downstream side Negative pressure securing means for supplying negative pressure;
When said vacuum retention means is activated, and a reduction means for performing power consumption reduction process to reduce the power consumption in the vehicle,
Further, the reduction means suppresses or prohibits the operation of a radiator fan as the power consumption reduction process in a range that does not cause overheating of the internal combustion engine,
A negative pressure supply device for a vehicle. The vehicle negative pressure supply device according to claim 1,
The reducing means suppresses the operation of the radiator fan by changing a threshold value of the cooling water temperature of the internal combustion engine at which the radiator fan starts to operate to a value higher than a normal value;
A negative pressure supply device for a vehicle. In the negative pressure supply device for a vehicle according to claim 1 or 2,
The reduction means implements a load reduction process for reducing a load applied to the crankshaft of the internal combustion engine together with the power consumption reduction process when the negative pressure securing means operates;
A negative pressure supply device for a vehicle. The negative pressure supply device for a vehicle according to claim 3 ,
The reduction means prohibits the compressor of the air conditioner from being driven by the crankshaft as the load reduction process.
A negative pressure supply device for a vehicle. In the negative pressure supply device for a vehicle according to claim 3 or claim 4 ,
The reduction means suppresses or prohibits power generation of a power generation device driven by the crankshaft as the load reduction processing,
A negative pressure supply device for a vehicle .

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