JP5870710B2 - Vehicle equipped with electric power steering system and method for supplying hydraulic pressure thereof - Google Patents

Description

The present invention includes an electric power steering system that makes the steering operation comfortable while the vehicle is running by the hydraulic pressure of the hydraulic pump that is electrically driven, and supplies standby hydraulic pressure to a mission that uses hydraulic pressure while the vehicle is idling . The present invention relates to a vehicle and its hydraulic pressure supply method.

  In recent years, various auxiliary systems have been installed in vehicles to make the vehicles run smoothly and reduce fuel consumption. One of them is a power steering system. This power steering system makes the driving of the vehicle comfortable and makes the operation simple and accurate.

  For example, a device that hydraulically drives a power steering, a clutch, and a transmission using a dual hydraulic pump driven by an engine crankshaft (see, for example, Patent Document 1), or between an engine and an oil pump. In addition, there is a device (for example, refer to Patent Document 2) that supplies pressure oil even when the engine is stopped or at a low rotation speed by a one-way clutch provided between the motor and the oil pump.

  Further, the fuel efficiency of the vehicle can be improved by driving the power steering system with a motor (electric motor). As this electric power steering system, an electric power steering system (hereinafter referred to as an EPS system) is usually mounted on a vehicle, and an electric pump power steering system (hereinafter referred to as an EHPS system) is installed on a heavy vehicle on which the EPS system cannot be mounted. Is often installed.

  However, by mounting the EHPS system, there arises a problem of deterioration in fuel efficiency resources due to power consumption for separately driving an electric motor and deterioration in mountability on a vehicle.

  On the other hand, mounting an idling stop system (hereinafter referred to as ISS) on a vehicle is advancing as a technique for improving fuel consumption. However, in a vehicle equipped with a hydraulic transmission such as an automatic transmission (AT), a semi-automatic transmission (AMT), and a continuously variable transmission (CVT), it is necessary to ensure a driving force promptly after returning to the ISS.

  Thus, as an auxiliary system, there is a system that supplies standby hydraulic pressure to a mission that uses hydraulic pressure while idling is stopped, using an electric pump. In this system, the engine is stopped during ISS operation, that is, idling stop, and even after returning from idling stop, the hydraulic pressure cannot be obtained immediately after starting the engine (generally around 1 second). Necessary), standby hydraulic pressure is supplied to the mission using hydraulic pressure with an electric pump.

  However, it is necessary to provide an electric pump separately, and there is a problem that mountability on a vehicle is deteriorated. Further, moving the system that supplies the standby hydraulic pressure while idling is stopped increases the power consumption during idling stop. According to the graph of the influence of power consumption during idling in FIG. 4, when the power consumption during idling stop is large, the alternator power generation amount increases for charging the battery after the engine restarts, and the engine load increases. Therefore, it can be seen that the fuel consumption increases, and the actual effect of mounting the ISS decreases.

In other words, in order to solve the problem that the driving force cannot be obtained immediately after restarting the engine, which occurs due to the installation of the ISS to improve fuel consumption, a system that supplies standby hydraulic pressure to a hydraulic transmission is provided. If installed, about 3.0 to 4.0 A is required during idling stop of the vehicle, and the problem that the effect of improving the fuel consumption decreases newly arises.

  Moreover, the same problem occurs when the above-described EHPS system is mounted on a vehicle. While the vehicle is idling stopped, it is not necessary to operate the EHPS system, but it requires about 0.5 to 1.0 A simply by keeping the system on standby.

  Therefore, if an EHPS system and a system for supplying standby oil pressure are provided at the same time, a total of about 4.0 to 6.0 A is increased during idling stop of the vehicle. Here, according to the graph showing the influence of the fuel efficiency of the alternator and the battery power in FIG. 5, it is understood that when the current amount of the alternator and the battery increases by 1 A, the fuel efficiency is deteriorated by about 0.5 to 0.7%. Therefore, when both systems are mounted on a vehicle, as shown in FIG. 4, the fuel efficiency reduction effect of 3 to 7% is reduced, and the effect of mounting the worst ISS is offset. In order not to reduce the fuel consumption reduction effect by installing the ISS, it is necessary to reduce the amount of current during idling stop of the vehicle as much as possible.

  As described above, the mounting of the auxiliary system has a problem that the mounting property to the vehicle is deteriorated and the fuel consumption is deteriorated due to a decrease in fuel resources due to an increase in power consumption.

Japanese Utility Model Publication No. 1-1114477. JP 2006-316666 A

The present invention has been made in view of the above problems, and an object thereof is to reduce fuel consumption by combining a power steering system and a system for supplying hydraulic pressure to a mission that uses hydraulic pressure during idling stop. It is intended to provide a vehicle including an electric power steering system that can suppress the deterioration of mountability and suppress the deterioration of the mountability, and a hydraulic pressure supply method thereof.

A vehicle equipped with an electric power steering system according to the present invention for solving the above-described object includes a first hydraulic pump that supplies hydraulic pressure to a steering assist device that assists the steering performance of the vehicle while the vehicle is running, and the first hydraulic pump. In a vehicle including an electric power steering system having an electric motor that drives a hydraulic pump, at least one of a driving force transmission device, a vehicle stopping device, and a cooling device during the idling stop system and idling stop of the vehicle by the idling stop system. A standby hydraulic pressure supply system having a second hydraulic pump for supplying hydraulic pressure to the motor, and a control device for controlling the electric motor, via a first one-way clutch that transmits rotation to the electric motor at the time of normal rotation of the electric motor. When the first hydraulic pump is connected and the motor rotates backward The second hydraulic pump is connected via a second one-way clutch that transmits rotation, and the control device rotates the motor forward only while the vehicle is running, and the steering assist device is operated by the first hydraulic pump. The hydraulic pressure is supplied to the standby hydraulic pressure supply system by the second hydraulic pump only during idling stop of the vehicle which does not need to assist the steering performance of the vehicle. It is characterized by performing control to perform.

  According to this configuration, the second hydraulic pump driven by the electric motor of the power steering system is used to drive the internal combustion engine drive force (AT, AMT, CVT, etc.) and the vehicle stop device (brake) while the vehicle is idling. The hydraulic pressure can be supplied to a caliper or the like, and a cooling device (oil cooler or the like).

It is not necessary to supply hydraulic pressure to the power steering system except when the vehicle is traveling, and it is not necessary to supply hydraulic pressure to the standby hydraulic control system except when the vehicle is idling stopped. Therefore, by sharing the electric motors used in these systems where the drive timings do not overlap, the two systems of the power steering system and the standby hydraulic control system can be made into one system. Thereby, the mounting property to a vehicle can be improved.

  The power steering system includes a control device that rotates the electric motor forward during traveling of the vehicle or reversely rotates during idling stop, and between the electric motor and the first hydraulic pump, A first one-way clutch that transmits the normal rotation of the electric motor and a second one-way clutch that transmits the reverse rotation of the electric motor between the electric motor and the second hydraulic pump; Or the above-mentioned effect can be acquired only by controlling to reverse rotation. Moreover, since one motor is shared by two systems, power consumption can be reduced, and as a result, fuel consumption can be reduced.

  In addition, a vehicle for solving the above problems includes an idling stop system and a power steering system including a first hydraulic pump that supplies hydraulic pressure to a steering assist device that assists the steering performance of the vehicle while the vehicle is running. And a standby hydraulic pressure supply that includes a second hydraulic pump that supplies hydraulic pressure to at least one of the driving force transmission device, the vehicle stop device, and the cooling device during idling stop of the vehicle that does not need to assist the steering performance of the vehicle In a vehicle comprising the system, the first hydraulic pump is driven by a single electric motor while the vehicle is running, and the second hydraulic pump is driven by a single electric motor while the vehicle is idling.

  According to this configuration, a vehicle equipped with an idling stop system can be equipped with a power steering system that is running with one system and a standby hydraulic pressure supply system that is during idling stop. As a result, the power steering system and the standby hydraulic pressure supply system can share one electric motor and one control device, thereby improving vehicle mountability and reducing costs. In addition, the reduction in fuel consumption generated by installing the standby hydraulic pressure supply system can be compensated for by improving the vehicle driving fuel consumption of the power steering system, and the reduction in fuel consumption can be suppressed comprehensively.

Furthermore, a vehicle hydraulic pressure supply method including an electric power steering system for solving the above problem is a steering assist device that assists the steering performance of the vehicle by a first hydraulic pump driven by an electric motor during traveling of the vehicle. In a vehicle hydraulic pressure supply method equipped with an electric power steering system for supplying hydraulic pressure to the vehicle, the first motor is normally rotated only while the vehicle is running, and the first one-way clutch is used to transmit the rotation at the time of the normal rotation of the motor. The first hydraulic pump is driven and hydraulic pressure is supplied to the steering assist device by the first hydraulic pump, and the electric motor is reversely rotated only during idling stop of the vehicle that does not need to assist the steering performance of the vehicle. The second hydraulic pump is driven via a second one-way clutch that transmits rotation when the electric motor rotates in the reverse direction. It reaches apparatus, a vehicle stopping device, and a method characterized by supplying hydraulic pressure to the at least one cooling device.

  According to this method, by configuring a system that can perform a hydraulic operation in combination, it is possible to suppress a reduction in fuel efficiency resources and suppress deterioration in mountability. Since the power steering system and the standby hydraulic pressure supply system are used in different areas, there is no overlapping operation area even when one electric motor is shared, and therefore it can be combined.

  According to the present invention, by combining a power steering system and a system that supplies hydraulic pressure to a mission that uses hydraulic pressure while idling is stopped, it is possible to suppress a reduction in fuel consumption and a deterioration in mountability.

1 is a schematic diagram showing a vehicle equipped with a power steering system according to an embodiment of the present invention. It is a fluid circuit diagram which shows the power steering system shown in FIG. It is the flowchart which showed the control method of the vehicle of embodiment which concerns on this invention. It is a graph which shows the power consumption in idling stop. It is a graph which shows the fuel consumption influence of the electric power of an alternator and a battery.

DESCRIPTION OF EMBODIMENTS Hereinafter, a vehicle including an electric power steering system according to an embodiment of the present invention and a hydraulic pressure supply method thereof will be described with reference to the drawings. In this embodiment, a rear-wheel drive type front engine rear drive type (hereinafter referred to as FR) vehicle that drives a rear wheel among front and rear wheels will be described as an example. However, the present invention is not limited to the FR. In addition, the present invention can be applied to a midship engine rear drive system (MR) and a rear engine rear drive system (RR). Further, the present invention is not limited to the rear wheel drive system, and can be applied to a front wheel drive system such as a front engine front drive system (FF).

  First, a vehicle equipped with a power steering system according to an embodiment of the present invention will be described with reference to FIG. Note that the upper side of FIG. 1 is the front of the vehicle, and the lower side is the rear of the vehicle. The vehicle 1 includes an engine (internal combustion engine) 2a, a clutch (driving force transmission device) 2b, a transmission (transmission device) 2c, a crankshaft 2d, an alternator (generator) 2e, and a cooling device (such as a radiator and a fan) 2f. The driving force generated in the power plant 2 is transmitted to the drive shaft 3 and travels with the rear wheels (not shown) as drive wheels.

  The vehicle 1 also includes an operation device 4 including a steering wheel (handle) 4a and a foot pedal (accelerator pedal, brake pedal, clutch pedal, etc.) 4b, and operates the front wheels 5a and 5b by the steering wheel 4a. Change direction.

  In addition, the vehicle 1 includes an ECU (control device) 6 called an engine control unit, a steering angle sensor 7, and a vehicle speed sensor 8. The ECU 6 is a microcontroller that comprehensively performs electrical control in charge of controlling the power plant 2 by an electric circuit based on information from the operation device 4 and each sensor (not shown). In this embodiment, the ECU 6 is provided with an idling stop system (hereinafter referred to as ISS), detects a decrease in vehicle speed, stops the engine 2a, detects a start operation of the operating device 4, and restarts the engine 2a. Take control.

  The configuration of the vehicle 1 is not limited to the configuration described above, and a known technology can be used. For example, the engine 2a may be a diesel engine, a gasoline engine, or an electric motor, and a continuously variable transmission (CVT) may be used as the transmission 2c. In addition to the engine 2a, a hybrid car provided with an electric motor may be used.

  In the vehicle 1 according to the embodiment of the present invention, in addition to the above configuration, an EHPS system (electric pump power steering system) 10 that operates in conjunction with the steering wheel 4a and steers the front wheels 5a and 5b, and an ISS And a standby hydraulic pressure supply system 20 that supplies standby hydraulic pressure to a mission that uses hydraulic pressure such as the power plant 2 during idling stop.

The EHPS system 10 includes a first hydraulic pump 11, a reservoir tank 12, and a power steering (steering assist device) 13 connected by a hydraulic pipe, and a standby hydraulic supply system 20 is connected to a hydraulic supply circuit (not shown) by a hydraulic pipe. The second hydraulic pump 21 is provided.

  One motor (electric motor) 30 that drives the first hydraulic pump 11 and the second hydraulic pump 21 is provided. The first hydraulic pump 11 is connected to the motor 30 via the first one-way clutch 31, and the second hydraulic pump 21 is connected to the motor 30 via the second one-way clutch 32. The first one-way clutch 31 and the second one-way clutch 32 are arranged symmetrically with respect to the motor 30, and are provided so as to transmit rotations in opposite directions.

  In this embodiment, when the motor 30 rotates forward, the first one-way clutch 31 transmits the rotation to the first hydraulic pump 11, and the second one-way clutch 32 transmits the rotation to the second hydraulic pump 21. First, the first one-way clutch 31 does not transmit the rotation to the first hydraulic pump 11 and the second one-way clutch 32 transmits the rotation to the second hydraulic pump 21 when the motor 30 rotates in the reverse direction. To do.

  The motor 30 only needs to be able to rotate the rotating shaft forward and backward, and a well-known motor can be used. The first one-way clutch 31 and the second one-way clutch 32 are also known one-way clutches. Can be used.

  According to this configuration, the EHPS system 10 and the standby hydraulic pressure supply system 20 can be integrated into one system, so that the mountability on the vehicle 1 can be improved. Further, by simply rotating the motor 30 forward or backward, the hydraulic pressure is supplied to the EHPS system 10 while the vehicle 1 is traveling, and the hydraulic pressure is supplied to the standby hydraulic pressure supply system 20 when the vehicle 1 is idling stopped. Can do. Thereby, control of two systems can be performed easily.

  Next, fluid circuits of the EHPS system 10 and the standby hydraulic pressure supply system 20 according to the embodiment of the present invention will be described with reference to FIG. The EHPS system 10 includes a line pressure control valve 14 and a one-way valve 15 in addition to the first hydraulic pump 11, the reservoir tank 12, and the power steering 13. The EHPS system 10 is not limited to the above configuration as long as it is supplied with hydraulic pressure by electric drive and can assist the steering operation of the vehicle 1.

  According to the EHPS system 10, the operation of the vehicle 1 can be made comfortable, the operation can be made simple and accurate, and the fuel pressure can be improved by supplying hydraulic pressure by the motor 30.

  The standby hydraulic pressure supply system 20 includes a second hydraulic pump 21, an oil tank 22, and a one-way valve 23. The standby hydraulic pressure supply system 20 is connected to a hydraulic pressure supply system 40 that is driven by driving the engine 2a, and supplies hydraulic pressure to the hydraulic pressure supply system 40 during an idling stop when the engine 2a stops.

  The hydraulic pressure supply system 40 includes an oil pump 41 driven by the engine 2a, an oil tank 42, a relief valve (line pressure control valve) 43, and an oil filter 44, and includes a driving force transmission device, a cooling device, and a vehicle stop device. Any device that supplies hydraulic pressure to at least one of the missions using hydraulic pressure may be used.

  As an example, in this embodiment, the hydraulic pressure supply system 40 includes an oil cooler circuit 45 including an oil cooler 45a, a cooler bypass circuit 45b, and a cooler 45c, a fluid coupling (fluid coupling) 46a, and a lock-up control valve. 46b, a fluid coupling circuit 46 including a lockup control valve 46c including a lockup solenoid, a clutch circuit 47 including a clutch 2b and a linear solenoid valve 47a for clutch control, and a brake caliper including a brake pad 48a and a brake piston 48b. 48.

  According to this standby hydraulic pressure supply system 20, standby hydraulic pressure can be supplied to the oil cooler circuit 45, the fluid coupling circuit 46, the clutch circuit 47, and the brake caliper 48 during idling stop of the engine 2 a due to the operation of the ISS. Thereafter, when the engine 2a is restarted, a driving force can be obtained quickly.

  Next, the operation of the vehicle 1 equipped with the EHPS system 10 according to the embodiment of the present invention will be described. While the vehicle 1 is traveling normally, the motor 30 is rotated in the forward direction by the ECU 6. The first one-way clutch 31 transmits the rotation to the first hydraulic pump 11, and the first hydraulic pump 11 is driven. Thus, the hydraulic pressure can be supplied to the power steering 13 by driving the first hydraulic pump 11. At this time, since the second one-way clutch 32 does not transmit the rotation of the motor 30 to the second hydraulic pump 21 during the forward rotation, the standby hydraulic pressure supply system 20 does not supply hydraulic pressure to the hydraulic pressure supply system 40.

  On the other hand, when the vehicle 1 stops, the ISS operates to stop the engine 2a and stop idling. While the vehicle 1 is idling stopped, the ECU 30 causes the motor 30 to rotate in the reverse direction. The second one-way clutch 32 transmits the rotation to the second hydraulic pump 21 and the second hydraulic pump 21 is driven. Thus, by driving the second hydraulic pump 21, it is possible to supply hydraulic pressure to the standby hydraulic pressure supply system 20 and supply hydraulic pressure from the standby hydraulic pressure supply system 20 to the hydraulic pressure supply system 40. At this time, the first one-way clutch 31 does not transmit the rotation of the motor 30 to the first hydraulic pump 11 during reverse rotation, and therefore does not supply hydraulic pressure to the power steering system 10.

  According to this operation, the EHPS system 10 and the standby hydraulic pressure supply system 20 can be operated by one motor 30 and one ECU 6, so that the mountability on the vehicle 1 can be improved. Since the use areas of the EHPS system 10 and the standby hydraulic pressure supply system 20 are different, even when one motor 30 is shared, the operation areas of the motor 30 do not overlap and two systems can be operated. Further, since only one motor 30 and one ECU 6 are required, the cost can be reduced and the control can be simplified.

  In addition, by combining the EHPS system 10 and the standby hydraulic pressure supply system 20 that increase the cost when each unit is mounted, the EHPS system 10 can provide a comfortable operability of the vehicle 1 and a deterioration in fuel consumption. Further, the standby hydraulic pressure supply system 20 can quickly secure the driving force when restarting from the idling stop.

  In addition, the EHPS system 10 has a problem that driving the motor 30 during idling stop and supplying hydraulic pressure to the standby hydraulic pressure supply system 20 increases power consumption during idling stop and reduces fuel consumption resources. Since the fuel consumption can be reduced by performing the control, the fuel consumption reduction effect of idling stop can be further obtained.

Furthermore, compared with the case where the EHPS system 10 and the standby hydraulic pressure supply system 20 are installed in the vehicle 1 as separate systems, the amount of current during the idling stop of the vehicle can be reduced, so that the engine 2a can be operated from the idling stop. When returning and restarting, the power generation amount of the alternator 2e can be reduced. Thereby, it is possible to suppress the reduction of the fuel resources, improve the fuel efficiency, and increase the fuel efficiency improvement effect by installing the ISS.

  Next, a vehicle control method according to an embodiment of the present invention will be described with reference to FIG. First, step S1 for determining whether or not the vehicle 1 is traveling is performed. In this step S1, it is determined whether or not the vehicle 1 is traveling from the vehicle speed sensor 8 or a crank angle sensor (not shown). However, the method is not limited as long as the traveling state of the vehicle 1 can be detected.

  If it is determined in step S1 that the vehicle 1 is traveling, then step S2 is performed to determine whether or not the steering angle has changed. In step S2, a method of detecting the operation of the steering wheel 4a with the steering angle sensor 7 is used. If the steering angle does not change here, the process returns to step S1.

  If it is determined in step S2 that the steering angle has changed, next, step S3 is performed to rotate the motor 30 forward and supply hydraulic pressure to the EHPS system 10. Since this step S3 is performed by changing the steering angle, the motor 30 can be driven only when the EHPS system 10 needs to be supplied with hydraulic pressure, so that power consumption can be further suppressed and fuel consumption can be reduced. be able to.

  If it is determined in step S1 that the vehicle 1 is not traveling normally, then step S4 is performed to determine whether or not the vehicle 1 is idling stopped. In step S4, a determination is made based on the ISS information. However, it is only necessary to be able to determine whether or not the engine 2a is stopped by the ISS. For example, a method using a crank angle sensor, a hydraulic pressure supply system 40, or the like. A method of determining whether or not the hydraulic pressure is supplied to the hydraulic pressure supply system by providing a hydraulic pressure sensor may be used.

  If it is determined in step S4 that the vehicle 1 is idling stopped, next, the motor 30 is reversely rotated, and step S5 for supplying hydraulic pressure to the standby hydraulic pressure supply system 20 is performed. If it is determined in step S4 that the vehicle 1 is not idling stopped, the process returns to step S1.

  According to this control method, the EHPS 10 that requires hydraulic pressure during traveling and does not require hydraulic pressure during idling stop and the standby hydraulic pressure supply system 20 that does not require hydraulic pressure during traveling and requires hydraulic pressure during idling stop are unified. One motor 30 can be controlled as one system. Thereby, the deterioration of the mounting property which generate | occur | produces when mounting two systems can be suppressed. In addition, since the operation and effect when the EHPS system 10 is installed and the operation and effect when the standby hydraulic pressure supply system 20 is installed can be obtained at the same time, the fuel consumption reduction effect by the ISS can be further improved.

  The power steering system of the present invention supplies hydraulic pressure to the power steering system while the vehicle is running, and supplies hydraulic pressure to the standby hydraulic pressure supply system that supplies standby hydraulic pressure to the mission using hydraulic pressure when the vehicle is idling stopped. Therefore, it is possible to suppress the deterioration of the mountability to the vehicle and also to suppress the reduction of the fuel resources, so that it can be used for the vehicle equipped with the idling stop system.

1 Vehicle 2 Power Plant 3 Drive Shaft 4 Operating Device 6 ECU (Control Device)
10 EHPS system (electric pump power steering system)
11 First hydraulic pump 20 Standby hydraulic supply system 21 Second hydraulic pump 30 Motor (electric motor)
31 1st one-way clutch 32 2nd one-way clutch 40 Oil pressure supply system (system which supplies oil pressure to the mission which uses oil pressure)

Claims (2)

In a vehicle including a first hydraulic pump that supplies hydraulic pressure to a steering assist device that assists the steering performance of the vehicle while the vehicle is running, and an electric power steering system that includes an electric motor that drives the first hydraulic pump.
An idling stop system, and a standby hydraulic pressure supply system having a second hydraulic pump for supplying hydraulic pressure to at least one of the driving force transmission device, the vehicle stopping device, and the cooling device during idling stop of the vehicle by the idling stop system; And a control device for controlling the electric motor,
The first hydraulic pump is connected to the electric motor via a first one-way clutch that transmits rotation when the electric motor is rotated forward, and the second hydraulic motor is connected via a second one-way clutch that transmits rotation when the electric motor is reversely rotated. A second hydraulic pump is connected,
Vehicle that does not need to assist the steering performance of the vehicle by controlling the forward rotation of the electric motor and supplying the hydraulic pressure to the steering assist device by the first hydraulic pump only when the control device is running. An electric power steering system configured to perform control to reversely rotate the electric motor and to supply hydraulic pressure to the standby hydraulic pressure supply system by the second hydraulic pump only during idling stop Vehicle. In a vehicle hydraulic pressure supply method including an electric power steering system that supplies hydraulic pressure to a steering assist device that assists the steering performance of the vehicle by a first hydraulic pump driven by an electric motor during traveling of the vehicle,
Only when the vehicle is running, the electric motor is normally rotated, and the first hydraulic pump is driven via a first one-way clutch that transmits the rotation at the time of the normal rotation of the electric motor, and the steering assist is performed by the first hydraulic pump. Supply hydraulic pressure to the equipment,
The second hydraulic pump is driven via a second one-way clutch that reversely rotates the electric motor and transmits the rotation at the time of reverse rotation of the electric motor only during idling stop of the vehicle that does not need to assist the steering of the vehicle. A method for supplying hydraulic pressure to a vehicle with an electric power steering system, wherein the second hydraulic pump supplies hydraulic pressure to at least one of a driving force transmission device, a vehicle stopping device, and a cooling device.