JP2014152610A - Automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To forcibly reduce the speed of an automobile, when a brake booster malfunctions due to the occurrence of a trouble such as a throttle valve is kept opened, in an automobile equipped with the brake booster using intake negative pressure.SOLUTION: An internal combustion engine is equipped with a power supplying/interrupting type auxiliary apparatus such as an alternator 15 freely connecting/disconnecting drive by a crank shaft. When a brake request of a driver is made while the pressure of an intake passage is fixed to atmospheric pressure side, the power supplying/interrupting auxiliary apparatus is forcibly driven. By applying a load on the internal combustion engine, the speed of an automobile is reduced, and a driver can take an evacuation action while improving safety.

Description

  The present invention relates to an automobile equipped with a negative pressure brake booster that amplifies the depression force of a brake pedal.

  In automobiles such as passenger cars, braking is applied by depressing the brake pedal. However, since it is difficult to secure the necessary braking force with only human power, a brake booster that amplifies the depressing force of the brake pedal is provided. This brake booster is a gas drive type, and is a negative pressure type using the intake air of the internal combustion engine as a drive gas, and drives the power piston of the brake booster using the pressure difference between the intake negative pressure and the atmospheric pressure. It is configured as follows.

  Decreasing braking force in automobiles is a serious problem, and if the driver feels that the braking force has decreased, safety is ensured by taking retreating action such as approaching the side of the road. There are various causes for the reduction of the braking force, and Patent Document 1 describes that as a countermeasure when the electronic throttle breaks down, the ignition timing is advanced to the advance side to ensure the braking force (engine brake).

JP 2011-132888 A

  The electronic throttle is set to return to the reference angle (opener opening) with a low opening when it fails, so the control system and actuator are only broken when the throttle valve can be opened and closed. If not, it can be said that the countermeasure of Patent Document 1 is also effective.

  However, for example, if for some reason foreign matter gets mixed in during intake, and this bites into the throttle valve, the throttle valve remains open and cannot be closed, it is impossible to apply negative pressure to the brake booster itself. Or since it becomes incomplete, in patent document 1, it will become impossible to respond.

  The present invention has been made to improve the current situation, and aims to enable the driver to take the retreat action as safely as possible even when the function of the brake booster is stopped or reduced. Is.

  In order to achieve the above object, according to the first aspect of the present invention, an internal combustion engine having an intake passage and a power interrupting accessory is mounted as a driving power source, and the depression force of the brake pedal reduces the negative pressure in the intake passage. In a configuration that is amplified by the used brake booster, a negative force that acts on the brake booster when the rotational speed of the internal combustion engine is equal to or higher than a predetermined set value and there is a depression of the brake pedal or other braking request exists. When the pressure is lower than the normal value on the atmosphere side, the attached device is forcibly driven.

  According to the second aspect of the present invention, an internal combustion engine having an intake passage and a power interrupting type accessory is mounted as a travel power source, and a stepping force of a brake pedal is amplified using the negative pressure of the intake passage. A throttle booster that controls the flow rate in the intake passage, and the number of revolutions of the internal combustion engine is equal to or higher than a predetermined set value and the brake pedal is depressed or other When it is determined that the opening / closing of the throttle valve is abnormal while the braking request is present and the negative pressure acting on the brake booster is lower than the normal value to the atmosphere side, the attached device is forced Driven.

  In the present invention, the power interrupting type accessory means a device capable of remotely disconnecting the power while being driven by the power of the crankshaft, and representative examples thereof include an alternator and an air conditioner compressor.

  In the present invention, even if, for example, the throttle valve is fixed so that it cannot be closed or a hole is formed in the intake passage, the brake booster does not function at all or the degree of amplification becomes weaker than normal. Since the engine brake can be applied to the engine by applying the load of the attached device to the rotation of the shaft, the drivability can be improved when the driver decelerates the vehicle and takes the evacuation action.

  In addition, since the compulsory drive of the accessory device is executed at a preset rotation speed or higher, the accessory device is forcibly driven in a low speed range such as the idling rotation speed, leading to an engine stall. Can be prevented. Therefore, the present invention can support the driver's evacuation action without causing a situation in which the driver cannot control the automobile.

It is a schematic diagram which shows embodiment of this invention.

(1) Internal combustion engine / travel drive system Next, an embodiment of the present invention will be described with reference to the drawings. First, the structure of the internal combustion engine and the travel drive system will be described. A three-cylinder internal combustion engine 1 is mounted on an automobile, and the internal combustion engine 1 includes an engine body 2 having a cylinder block and a cylinder head as main elements. An intake manifold 3 is fixed to one side surface of the cylinder head constituting the engine body 2, and an exhaust manifold 4 constituting a part of the exhaust passage is fixed to the other side surface of the cylinder head.

  An intake passage 6 starting from an air cleaner 5 is connected to the intake manifold 3, and a throttle valve 7 and a surge tank 8 on the downstream side thereof are provided in the intake passage 6. The throttle valve 7 is controlled to be opened and closed by an actuator 9 such as an electric motor, and the opening degree of the throttle valve 7 is detected by first and second opening degree sensors 10 and 11.

  A chain cover 12 that covers a timing chain for driving the valve operating mechanism is fixed to one side surface 2 a of the engine body 2, and an auxiliary machine drive belt wound around an auxiliary machine drive pulley 13 outside the chain cover 12. 14 is arranged. The auxiliary machine drive pulley 13 is fixed to one end of the crankshaft, and an auxiliary machine drive belt 14 drives an alternator 15, an air conditioner compressor 16, and a water pump 17.

  The alternator 15 and the air conditioner compressor 16 are examples of the power-interruptible accessory device, and the alternator 15 can remotely select driving and stopping by exciting the coil. In addition, the air conditioner compressor 16 can switch power by disengaging a built-in clutch.

  The alternator 15 is normally driven according to the amount of charge of the battery and the amount of power used by the headlight, but in this embodiment, it can be driven forcibly regardless of the demand from the battery or the like. On the other hand, the air conditioner compressor 16 is also automatically controlled to be turned ON / OFF in accordance with the evaporator temperature or the like, but in this embodiment, it is forcibly driven regardless of the demand for the evaporator temperature or the like. be able to.

  A transmission 19 such as a CVT system is fixed to the other side surface 2 a of the engine body 2. The rotational power of the main shaft 20 of the transmission 19 is transmitted to the rear wheels (drive wheels) 23 via the plurality of bevel gears 21 and the plurality of transmission shafts 22. A brake disc 25 is fixed to the axle 24 to which each wheel 23 is fixed, and a braking force is applied to the automobile by sandwiching the brake disc 25 with a hydraulically driven pad device 26.

(2) Brake mechanism Next, the structure around the brake will be described. A brake pedal 28, which a driver steps on with his / her foot, is attached to the driving floor of an automobile so as to rotate around the upper end portion. A brake rod 29 in a substantially horizontal posture is connected to a portion of the brake pedal 28 below the rotation fulcrum so as to be relatively movable, and the forward force of the brake rod 29 is amplified by the brake booster 30.

  The brake booster 30 includes an amplification chamber 31 and a control chamber 32 through which a brake rod 29 penetrates. A power piston 33 is slidably fitted in the amplification chamber 31, and a control valve plunger 34 is fitted in the control chamber 32. Fits slidable.

  The power piston 33 and the control valve plunger 34 are provided integrally with the brake rod 29 or fixed as separate members. In any case, the power piston 33 and the control valve plunger 34 are connected to the brake rod 29. Slide together.

  The tip of the brake rod 29 is in contact with the main piston 36 built in the master cylinder 35. The master cylinder 35 and the hydraulically driven pad device 26 are connected by a hydraulic line 37. When the main piston 36 moves forward, the hydraulic pressure is actuated on the hydraulically driven pad device 26, and the brake differential 25 is sandwiched between the pads. . This puts a brake on the driving of the car.

  The brake booster 30 uses the intake negative pressure of the internal combustion engine 1 as a drive source. For example, the intake manifold 3 and the tip of the amplification chamber 31 are connected by a negative pressure introduction passage 38. A branch passage 38 a branches from a portion of the negative pressure introduction passage 38 connected to the amplification chamber 31, and the branch passage 38 a is connected to the middle portion of the control chamber 32.

  One end of the control tube 39 is connected to the end of the amplification chamber 31 close to the control chamber 32, the other end of the control tube 39 branches into two, and one branch 39a is controlled. Connected to the front portion of the chamber 32, the other branch portion 39 b is connected to the rear portion of the control chamber 32 close to the brake pedal 28. An air release pipe 40 that is open to the atmosphere is connected to the rear of the control chamber 32 close to the brake pedal 28. The atmosphere release pipe 40 is connected to the same position as the other branch part 39 b of the control pipe 39.

  FIG. 1 shows a state in which the brake pedal 28 is depressed. In this state, the negative pressure taken in the intake passage 6 flows into the front chamber 32 a of the amplification chamber 32 and sucks the power piston 33. Thereby, the depression force of the brake pedal 28 is amplified.

  In this state, since the control valve plunger 34 is moving forward, the rear portion of the control chamber 32 is vacant, and the control tube 39 and the atmosphere release tube 40 are in communication with each other. The chamber 31b is open to the atmosphere, and the air accumulated in the rear chamber 31b is released to the atmosphere. Therefore, the power piston 33 is sucked and moved by the intake negative pressure without receiving resistance.

  When the brake pedal 28 is returned by a spring (not shown), the rear portion of the control chamber 32 is closed by the control valve plunger 33 and the front portion is opened, and the negative intake pressure is supplied to the rear of the amplification chamber 31 via the control pipe 39. Acting on the chamber 31b, there is no pressure difference between the front chamber 31a and the rear chamber 31b of the amplification chamber 31, and the control valve plunger 33 is easily retracted by the force of the spring.

  A side brake 41 and a travel shift lever 42 are provided near the driver's seat in the vehicle, and movements of the side brake 41 and the travel shift lever 42 are detected by operation detection sensors 32 and 44, respectively. The depression of the brake pedal 28 is detected by the pedal sensor 45.

(3). Control in the event of a throttle valve failure The internal combustion engine 1 includes an ECU (engine control unit) 46 as a control device. As is well known, the ECU 46 includes a CPU, volatile and nonvolatile memories, and the like. Then, the opening sensors 10 and 11 of the throttle valve 7, the pedal sensor 45, the side brake operation detection sensor 43, and the travel shift lever position detection sensor 44 are connected. The actuator 9, alternator 15, and air compressor 16 of the throttle valve 7 are also electrically connected to the ECU 46. A rotation sensor 48 that detects the number of rotations of the crankshaft is provided on one side of the engine body 2 where the chain cover 12 is provided. The rotation sensor 48 is also connected to the ECU 46.

  In addition, an intake pressure sensor 47 is provided in, for example, the surge tank 8 in the intake passage 6, and the intake pressure sensor 47 is also electrically connected to the ECU 46. In the present embodiment, the intake pressure sensor 47 also functions as a sensor that detects the negative pressure for the brake booster. As a means for detecting the negative pressure for the brake booster, for example, a pressure sensor may be provided in the amplification chamber 31 or the negative pressure introduction passage 38.

  The opening degree of the throttle valve 7 is detected by the first and second opening degree sensors 10 and 11, but two are provided so that even if one of them fails, only the other can be detected. It is. Usually, the opening degree of the throttle valve 7 is accurately detected by the two opening degree sensors 10 and 11. In the present embodiment, the opening sensors 10 and 11 function as means for detecting an opening abnormality of the throttle valve 7 (an electronic throttle abnormality).

  The pedal sensor 45, the side brake operation detection sensor 43, and the travel shift lever position detection sensor 44 function as braking request detection means for detecting the driver's braking intention to stop (or decelerate) the automobile. doing.

  The throttle valve 7 is, for example, a butterfly valve system. However, the throttle valve 7 is in a state where the throttle valve 7 is largely opened due to foreign matter mixed in between the support shaft and the bearing or adhesive liquid adhering thereto. Even if a closing signal is issued to the actuator 9, it is expected that the throttle valve 7 cannot be closed and controlled without moving the actuator. In that case, since the intake passage 6 is maintained in a negative pressure state close to the atmospheric pressure, the brake booster 31 cannot be operated at all or almost, and the automobile can hardly be braked. May occur.

  Therefore, when the pedal sensor 45 is ON and the throttle valve 7 is kept open even though the closing signal is issued to the actuator 9, the opening sensor follows the control signal of the actuator 9. 10 and 11 do not detect the closing movement of the throttle valve 7), the engine speed is equal to or higher than the speed at which the engine does not stall even if the attached device is fully driven (set speed). On the condition that the pressure is lower than the normal value to the atmospheric pressure side, the brake booster 30 is malfunctioning due to the abnormality (failure) of the throttle valve 7 despite the driver's request for braking. If the alternator 15 and the air conditioner compressor 16 are not driven, these are forcibly driven to load the internal combustion engine 1 (engine block). Over key) forced to apply the.

  As a result, the driving force transmitted to the wheels 23 is suppressed, the automobile decelerates, and the driver can take a retreating action such as approaching the side of the road with increased safety. When the vehicle is not downhill, the brake speed is maintained and the vehicle speed decreases further, and it is possible to eventually stop.

  If the foot brake is not effective, the driver often pulls the side brake 41 (stepping in the case of a stepping type) or lowers the travel shift lever 42 to a low speed (L or B). In addition to (or instead of) ON, the side brake operation detection sensor 43 is turned ON, and the travel shift lever position detection sensor 44 detects shift down, or both. It is also possible to execute forced driving of the alternator 15 and the like.

  When two opening sensors 10 and 11 are provided, the abnormality detection mode of the throttle valve 7 may be forcibly driven when any one of the opening sensors 10 and 11 detects an abnormality, Forcibly driving the alternator 15 or the like may be executed on condition that both the opening sensors 10 and 11 detect an abnormality. Since it is important for detection of an abnormal situation that the detection value by the intake sensor 46 stays high at the atmospheric pressure side and does not change, if the detection value by the intake pressure sensor 47 stays high at the atmospheric pressure side, If only one of the opening sensors 10, 11 generates an abnormal signal, the alternator 15 or the like may be forcibly driven.

  If the alternator 15 is of a variable power generation type and is driven with a low power generation amount and a failure of the throttle valve 7 is detected, the alternator 15 may be controlled to maximize the power generation amount. When the power generation amount of the alternator 15 depends on the power consumption, the power consumption can be maximized by forcibly lighting the headlight or forcibly driving the radiator fan.

  Whether or not the negative pressure acting on the brake booster 30 is normal is compared with a map (normal value, reference value) in which the detected value of the intake pressure sensor 47 is set based on an instruction signal from the ECU 46 to the throttle valve 7. Can be judged.

  That is, when the driver is stepping on the brake pedal 28, the driver's feet are away from the accelerator pedal, so that a close signal is issued to the throttle valve 7, but the throttle valve 7 is actually closed normally. Then, the state where the intake negative pressure is increased to the vacuum side while the brake booster 30 exhibits the desired amplification power is regarded as a normal state, and the intake negative pressure at that time is stored as a normal value (reference value). If the actual intake negative pressure (detected value of the intake pressure sensor 47) deviates beyond the set range so that it is higher than the normal value, the negative pressure is normal to the brake booster 30. If it is judged that it is not acting on.

  The reason why the negative pressure is not normally applied to the brake booster 30 is that the throttle valve 7 is not closed but remains open even though a closing signal is issued from the ECU 46 to the throttle valve 7. Although the valve 7 is closed as instructed by the ECU 46, there are two types of cases where a leak occurs due to a hole in the intake passage 6 or the like. If the value detected by the atmospheric pressure sensor 47 is abnormally lower than the reference value (normal value) on the atmospheric pressure side, the rotation can be suppressed by forcibly driving the alternator 15 or the like regardless of the cause.

  As described above, the forcible drive of the alternator 15 and the air conditioner compressor 16 is not performed in the low rotation speed range that leads to engine stall due to their full drive. For example, the set rotation speed is set to the first set rotation speed and the second rotation speed higher than this. If the actual rotational speed is higher than the second rotational speed, both the alternator 15 and the air conditioner compressor 16 are driven, and the actual rotational speed is the first rotational speed and the first rotational speed. When it is between two revolutions, only one of the alternator 15 and the air conditioner compressor 16 is forcibly driven. When the actual revolution is lower than the first revolution, both are not forcibly driven. It is also possible to control it.

  The present invention can be embodied by being applied to an automobile driven by an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Engine body which has a cylinder block and a cylinder head as main elements 3 Intake manifold 6 Intake passage 7 Throttle valve 9 Throttle valve opening / closing actuator 10, 11 Throttle valve opening sensor 14 Auxiliary drive belt 16 Power disconnection An alternator 17 as an example of a type attached device 17 A compressor for an air conditioner as an example of a power interrupting type attached device 23 Wheel 25 Brake disc 28 Brake pedal 30 Brake booster 31 Amplifying chamber 33 Power piston 34 Control valve plunger 38 Negative pressure introduction passage 40 ECU ( Control device)
41 Side brake 42 Travel shift lever 43 Side brake operation detection sensor 44 Travel shift lever position detection sensor 45 Pedal sensor 47 Intake pressure sensor

Claims (2)

An internal combustion engine having an intake passage and a power interrupting type accessory device is mounted as a traveling power source, and the depression force of the brake pedal is amplified by a brake booster using the negative pressure of the intake passage,
The negative pressure acting on the brake booster becomes lower than the normal value to the atmosphere side when the rotational speed of the internal combustion engine is equal to or higher than a predetermined set value and there is a depression of the brake pedal or other braking request. The attached device is forcibly driven,
Automobile. An internal combustion engine having an intake passage and a power interrupting type accessory is mounted as a driving power source, and a brake booster that amplifies the depressing force of the brake pedal using the negative pressure of the intake passage. The throttle passage for controlling the flow rate is arranged in the intake passage,
When the number of revolutions of the internal combustion engine is equal to or greater than a predetermined set value and the brake pedal is depressed or other braking request is present, it is determined that the opening / closing of the throttle valve is abnormal and the brake booster When the negative pressure acting on the air is lower than the normal value to the atmosphere side, the attached device is forcibly driven,
Automobile.

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