JPH06239169A - Drive system control device vehicle equipped with active suspension - Google Patents

Abstract

PURPOSE:To enable each actuator be well supplied with/emptied of working fluid with no energy consumed uselessly. CONSTITUTION:This invention is concerned with the drive system control device of a vehicle equipped with an active suspension which includes an engine 40 and an automatic transmission 56, includes each actuator 16 which is provided for each wheel, allows height at the corresponding site to be increased/decreased with the actuator supplied with/emptied of working fluid, includes a working fluid supply source with a pump 42 driven by the engine, and also includes a control valve 30 controlling the suction/exhaust of working fluid from the working fluid supply source to each actuator. The pumping amount of working fluid per hour to each actuator is estimated by a pumping amount estimating means 52 and 64, when the pumping amount is in excess of a specified value, each step of gear shifting of the automatic transmission is shifted down by integrated control means 60, 62 and 69, so that engine revolution is thereby increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle such as an automobile equipped with an active suspension, and more particularly to a drive system control device for a vehicle equipped with an active suspension.

[0002]

2. Description of the Related Art An active suspension of a vehicle such as an automobile is provided corresponding to each wheel as described in, for example, Japanese Patent Laid-Open No. 219408/1988. An actuator that increases or decreases the vehicle height of, a control valve that controls the supply and discharge of working fluid to and from the actuator, a working fluid supply source that includes a pump and an accumulator driven by an engine, and that supplies a working fluid such as oil to the control valve, It has a control device which controls a control valve according to a running state of a vehicle.

With such an active suspension, it is possible to effectively suppress changes in the posture of the vehicle body, such as rolls and pitches, which accompany traveling of the vehicle, and to transmit the vibration of the wheels due to the unevenness of the road surface to the vehicle body. Since this can be effectively suppressed, the steering stability and the riding comfort of the vehicle can be improved as compared with the case of the vehicle in which the active suspension is not mounted.

[0004]

In the above active suspension, the discharge flow rate Q of the pump driven by the engine is such that the engine speed Ne is less than the predetermined value Nt as shown in FIG. In this region, the engine speed gradually increases as the engine speed increases, and in a region where the engine speed Ne is equal to or higher than the predetermined value Nt, the constant value Qmax is maintained. If the working fluid is frequently supplied to and discharged from the actuator and the working fluid consumption increases when the engine speed is lower than Nt, such as when traveling on a rough road at high speed, the pressure in the accumulator increases. And the supply and discharge of the working fluid to and from the actuator are not properly performed due to insufficient supply pressure of the working fluid, and as a result, the steering stability and ride comfort of the vehicle are well controlled. It may not be possible to bet.

It is possible to use a high-capacity pump and set a high pump discharge flow rate so as to prevent the above-mentioned situation where the working fluid supply pressure is insufficient. However, the vehicle does not accelerate or decelerate or turn. In a situation where the amount of working fluid consumed is small, such as when traveling on a good road, the energy generated by the engine is wasted by the pump, which causes a new problem of deterioration of fuel efficiency.

In view of the above-mentioned problems in a vehicle equipped with a conventional active suspension, the present invention is an active system improved so that the working fluid can be satisfactorily supplied to and discharged from the actuator without wasting energy. It is an object of the present invention to provide a drive system control device for a vehicle equipped with a suspension.

[0007]

According to the present invention, the above-mentioned object has a corresponding portion by having an engine and an automatic transmission, and provided corresponding to each wheel and supplying and discharging a working fluid. Mounted with an active suspension having an actuator for increasing or decreasing the vehicle height of the vehicle, a working fluid supply source including a pump driven by the engine, and a control valve for controlling supply and discharge of the working fluid to and from each actuator from the working fluid supply source. And a discharge amount estimating means for estimating the supply / discharge amount of the working fluid to the actuator per unit time, and the automatic transmission of the automatic transmission when the supply / discharge amount is equal to or more than a predetermined value. This is achieved by a drive system control device having a pump output control means for downshifting the shift speed and increasing the engine speed.

[0008]

According to the above construction, the working fluid supply source includes the pump driven by the engine, and the supply / discharge amount estimating means estimates the supply / discharge amount of the working fluid to / from the actuator per unit time. Is greater than or equal to a predetermined value, the pump output control means shifts down the shift stage of the automatic transmission and increases the engine speed, so that the pump speed is increased without significantly changing the vehicle speed. It is possible to increase the supply amount of the working fluid by means of this, and it is possible to reliably prevent the supply and discharge of the working fluid to and from the actuator due to the insufficient supply of the working fluid.

[0009]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing one embodiment of a drive system control device for a vehicle equipped with an active suspension according to the present invention for a single wheel, and FIG. 2 is a block diagram showing the integrated control device shown in FIG. is there.

In FIG. 1, reference numeral 10 denotes a carrier that rotatably supports a wheel 12, and the carrier 10 and the vehicle body 1
An actuator 16 is arranged between the actuators 4 and 4. The actuator 16 comprises a cylinder 18 connected to the vehicle body 14 at its upper end, and a piston 20 pivotally mounted on the carrier 10 at its lower end and fitted to the cylinder so as to reciprocate. By supplying and discharging such a working fluid, the vehicle height of the corresponding portion is increased or decreased. A gas spring 26 is communicatively connected to the working fluid chamber 22 through a throttle passage 24, so that the gas spring 26 absorbs high-frequency pressure fluctuations in the working fluid chamber due to high-frequency relative displacement between the wheel and the vehicle body. It is like this.

Further, one end of a working fluid supply / discharge conduit 28 is connected to the working fluid chamber 22, and the other end of the supply / discharge conduit 28 is connected to a flow control valve 30. One end of a working fluid supply conduit 32 and one end of a working fluid discharge conduit 34 are connected to the flow rate control valve 30, and the other ends of these conduits are connected to a reservoir 36 that stores a working fluid. A pump 42 driven by an engine 40 via a pump drive shaft 38 is provided in the middle of the working fluid supply conduit 32, and an accumulator 44 communicates with the downstream side of the pump 42, that is, the flow control valve 30 side. It is connected.

The pump 42 has a flow rate characteristic as shown in FIG. 8, that is, in a region where the engine speed Ne of the engine 40 is less than a predetermined value Nt, the discharge flow rate Q of the pump gradually increases as the engine increases. , Has a flow rate characteristic in which the discharge flow rate Q is maintained at a constant value Qmax in a region where the engine speed Ne is equal to or higher than a predetermined value Nt.

The flow control valve 30 is three in the illustrated embodiment.
A port 3 position switching type flow control valve, and a shut-off position for shutting off communication between the supply / discharge conduit 28 and the supply conduit 32 / discharge conduit 34 in accordance with a control signal supplied from the suspension control device 46 to the solenoid 30A. A supply position for connecting and connecting the supply / discharge conduit 28 and the supply conduit 32;
And a discharge position where the discharge conduit 34 is connected for communication,
Accordingly, the working fluid chamber 2 of the corresponding actuator 16
The supply and discharge of the working fluid to and from the control unit 2 are controlled.

A pressure sensor 48 for detecting the pressure of the working fluid chamber 22 is attached to the cylinder 18 of the actuator 16, and an acceleration sensor 50 for detecting the vertical acceleration of the wheel 12 is attached near the lower end of the piston 20. Has been. Further, a vehicle height sensor 52 that detects a vehicle height H as a relative displacement between the wheel and the vehicle body is provided between the carrier 10 and the vehicle body 14. Suspension control device 4
Reference numeral 6 denotes signals from these sensors and a roll angular velocity sensor (not shown in FIG. 2) provided near the center of gravity of the vehicle body for detecting a roll angular velocity around the center of gravity of the vehicle body and a pitch for detecting a pitch angular velocity around the center of gravity of the vehicle body. Based on the signal from the angular velocity sensor, a control signal for reducing the influence of the disturbance that the wheels receive from the road surface and the acceleration acting on the vehicle body as the vehicle travels is output to the solenoid 30A of the flow control valve 30.

As described above, the suspension control device 46 is used.
Various control rules for calculating the control amount of the output control signal are conventionally known in the technical field, and the control rules themselves do not form the gist of the present invention. Although detailed description of the rules is omitted, any of these control rules may be used as long as the ride comfort of the vehicle can be improved and the posture change of the vehicle body can be suppressed.

As is well known, the output of the engine 40 is transmitted to the automatic transmission 56 via the automatic transmission input shaft 54, and the automatic transmission 56 outputs the automatic transmission at a rotation speed corresponding to the reduction gear ratio of the shift stage. The driving force is transmitted to a driving wheel (not shown) via the shaft 58. Engine 40
The engine speed Ne and the gear S of the automatic transmission 56 are controlled by the engine control device 60 and the automatic transmission control device 62, respectively, and the engine control device 60 and the automatic transmission control device 62 are controlled by the integrated control device 64. It is like this.

When the control flag F in the integrated control device 64 is 1 as described later, the engine control device 60:
The automatic transmission control device 62 is controlled by the integrated control device 64 in response to a command signal from the integrated control device regardless of the operation of the accelerator pedal by the vehicle driver. When the control flag F is 1, the shift operation of the automatic transmission 56 by the driver of the vehicle is prohibited, and the automatic transmission is downshifted in response to a command signal from the integrated control device. .

A signal indicating the vehicle height H detected by the vehicle height sensor 52, a signal indicating the engine speed Ne detected by the engine speed sensor 66 provided on the engine 40, and an automatic transmission are provided to the integrated control device 64. A signal indicating the number of rotations of the automatic transmission output shaft detected by the vehicle speed sensor 68 provided on the output shaft 58, that is, the vehicle speed V, and the automatic transmission detected by the shift position sensor 70 provided on the automatic transmission 56. A signal indicating the gear S is input.

The integrated controller 64 includes a microcomputer 72 as shown in FIG. The microcomputer 72 may have a general structure as shown in FIG. 2, and includes a CPU 74, a ROM 76 and a RAM.
78 and an input / output port device 80, which are connected to each other by a bidirectional common bus 82, and output a control signal to the engine control device 60 and the automatic transmission control device 62 as required, as described later. Drive circuit 8
A control signal for lighting the alarm lamp 84 is output via 4A. In particular, the ROM 76 stores a control program according to the flowchart shown in FIG. 3 and a map corresponding to the graph shown in FIG.

Although not shown in the drawing, the suspension control device 46, the engine control device 60, and the automatic transmission control device 62 also include a microcomputer having the same configuration as the microcomputer 72.

Next, the control of the engine speed Ne of the engine 40 and the gear S of the automatic transmission 56, that is, the control of the output of the pump 42, which is performed by the integrated control device 64, will be described with reference to the flow chart shown in FIG. To do. The control by the integrated control device 64 is started by closing an ignition switch (not shown).

First, in step 10, the signal indicating the vehicle height H detected by the vehicle height sensor 52 is read, and in step 20, the engine speed Ne is below a predetermined value Nt. It is determined whether or not there is, that is, whether or not the discharge flow rate Q of the pump 42 is equal to or less than the maximum value Qmax. When it is determined that Ne ≤ Nt is not satisfied, the process returns to step 10, and when it is determined that Ne ≤ Nt is satisfied, the distribution of the vehicle height H within the time T1 up to the present time is determined in step 30. It is determined whether or not the value Hr is greater than or equal to the reference value Hro (a positive constant), that is, whether or not the vehicle height fluctuates greatly and the amount of working fluid supplied to and discharged from the actuator 16 is high.

In step 30, the dispersion value Hr is the reference value Hr.
If it is determined that it is less than ro, step 10
When it is judged that Hr ≧ Hro, the alarm lamp is turned on by outputting a control signal to the alarm lamp 84 in step 40, whereby the operation on the upstream side of the flow control valve 30 is performed. Warning that there is a risk of insufficient fluid pressure, and it is preferable to shift down the automatic transmission and increase the engine speed, and the driver of the vehicle shifts down the automatic transmission and the engine speed. When no increase operation is performed, the vehicle driver is warned that these operations are automatically performed.

At step 50, it is judged whether or not the automatic transmission is downshifted by the driver of the vehicle. When it is judged that the downshift has been carried out, the process returns to step 10. When it is determined that the downshift has not been performed, it is determined in step 60 whether or not a predetermined time Tw (a positive constant) has elapsed since the warning lamp was turned on in step 40. Is done. When it is determined that the predetermined time Tw has not elapsed, the process returns to step 50, and when it is determined that the predetermined time Tw has elapsed, the control flag F is set to 1 in step 70. .

In step 80, the engine speed Ne is set to a value higher than the predetermined value Nt without substantially changing the vehicle speed based on the current vehicle speed Va from the map corresponding to the graph shown in FIG. The number of downshifts ΔS required
And the engine speed Nc in that case is calculated, and in step 90, a command signal for downshifting the automatic transmission 56 by the downshift number ΔS is output to the automatic transmission control device 62, and at the same time, the engine control device is output. A command signal for increasing the engine speed to Nc is output to 60.

In this case, when the downshift number ΔS is 1 as shown in FIG. 4, the engine speed Ne
Is increased quadratically from the shift time t ₁ to the time t ₂ , for example from Na to Nc as shown in FIG. Further, when the downshift number ΔS is 2 as shown in FIG. 6, the engine speed Ne is shown in FIG.
To which is increased from the Na during the first than to time t ₂ shift time t ₁ of the first stage as has Nm until quadratically shown, up to the point t ₃ from shift time t ₂ of thereafter the second stage In the meantime, the speed is increased as a quadratic function from Nm to Nc, which prevents the vehicle speed from abruptly changing due to the downshift of the automatic transmission.

In step 100, a predetermined time T has passed since the control flag F was set to 1 in step 70.
When it is determined whether or not c has elapsed, and it is determined that the time Tc has not elapsed, step 110
After waiting for a predetermined time at step 10
0 is repeatedly executed, and when it is determined that the time Tc has elapsed, the control flag F is set to 0 in step 120.
After being reset to, the process returns to step 10. The predetermined time T
c may be set to a constant value that is greater than or equal to the time required to complete the downshift of the automatic transmission and the increase in engine speed, and is not less than the time required to achieve these operations. It may be increased or decreased to a value proportional to the variance value Hr of the vehicle height.

Thus, according to the illustrated embodiment, it is determined in step 20 that the engine speed Ne is less than or equal to the predetermined value Nt, that is, the discharge flow rate Q of the pump 42 is the maximum value Qma.
It is determined that x is equal to or less than x, and it is determined in step 30 that the variance value Hr of the vehicle height is equal to or greater than the reference value Hro, that is, that the supply / discharge amount of the working fluid to / from the actuator 16 is high. Therefore, if there is a possibility that the discharge flow rate of the pump will be insufficient, first, at step 40, the alarm lamp 84 is turned on, whereby the automatic transmission is downshifted and the engine speed is increased. It is preferable that the driver of the vehicle does not perform the operation of downshifting the automatic transmission and increasing the engine speed.

When it is determined in steps 50 and 60 that the driver of the vehicle has not downshifted the automatic transmission, the control flag F is determined in step 70.
Is set to 1, the shift operation of the automatic transmission by the driver of the vehicle is prohibited, and it is necessary to set the engine speed Ne to the predetermined value Nt or more in step 80 without changing the vehicle speed V. The shift down number ΔS of the automatic transmission and the engine speed Nc when downshifting is performed by the shift down number are calculated, and step 9
At 0, a command signal is output to the automatic transmission control device 62 and the engine control device 60 according to the calculation result in step 80, whereby the automatic transmission 56 is downshifted by ΔS and the rotation speed Ne of the engine 40 is decreased. The discharge flow rate Q of 42 is increased to its maximum value Qma.
increased to x.

Therefore, according to the illustrated embodiment, the amount of working fluid supplied to and discharged from the actuator 16 is set as in the case where the gear S of the automatic transmission is set to a high gear and the vehicle travels on a rough road at low and medium vehicle speeds. Although the engine speed Ne is equal to or lower than the predetermined value Nt even though the engine speed is high, there is a possibility that the supply of the working fluid by the pump 42 will be insufficient.
Insufficient supply of the working fluid by the pump is solved by increasing the number of rotations of, so that the supply and discharge of the working fluid to and from the actuator are caused by the lack of the pressure of the working fluid on the upstream side of the flow control valve 30. It is reliably prevented that the vehicle is not satisfactorily performed and the control of the steering stability and the riding comfort of the vehicle is not satisfactorily performed.

Also according to the illustrated embodiment, the automatic transmission 5
The shift down of 6 and the increase of the rotation speed of the engine 40 are achieved without changing the vehicle speed V based on the map corresponding to the graph shown in FIG. 4, so that the discharge flow rate of the pump 42 is automatically increased. However, the vehicle speed does not change, so that it is possible to reliably prevent the driving safety from being impaired and the occupants of the vehicle to feel uncomfortable due to the increase or decrease of the vehicle speed.

Further, according to the embodiment shown in the figure, the engine speed when the automatic transmission is downshifted is quadratically increased as shown in FIG. 5 or FIG. It is possible to minimize the transitional change in vehicle speed when the transmission is downshifted.

Further, according to the embodiment shown in the drawings, when the automatic transmission is downshifted and the engine speed is increased automatically, the warning lamp 84 is turned on prior to the automatic downshifting of the vehicle driver. Since a warning is given to the driver, the driver of the vehicle can recognize that the vehicle is traveling on a bad road where the amount of working fluid supplied to and discharged from the actuator is high, and the automatic transmission can be used regardless of the driver's intention. It can be recognized that the shift down and the engine speed increase are automatically performed.

Although the present invention has been described above in detail with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments, and various other embodiments are also possible within the scope of the present invention. It will be apparent to those skilled in the art that

For example, in the above-described embodiment, the supply / discharge amount of the working fluid to the actuator per unit time is the reference value Hro when the variance value Hr of the vehicle height H within the time T1 up to the present time.
Although it is estimated based on whether or not the above, it may be estimated based on whether or not the vertical acceleration of the wheel 12 detected by the acceleration sensor 50 is equal to or greater than a reference value, and the vehicle height H is It may be estimated by the frequency of exceeding the reference value, the frequency of vertical acceleration of the wheels exceeding the reference value, the switching frequency of the flow control valve based on the command signal to the flow control valve 30, or the like.

In the illustrated embodiment, the engine speed when the automatic transmission is downshifted is increased by a quadratic function. It may be increased in any manner, as long as transient changes in vehicle speed during downshifting of the machine are reduced.

[0038]

As is apparent from the above description, according to the present invention, the supply / discharge amount estimating means estimates the supply / discharge amount of the working fluid to the actuator per unit time, and the supply / discharge amount is not less than the predetermined value. At some time, the pump output control means shifts down the gear of the automatic transmission and increases the engine speed, so that the pump speed is increased and the working fluid is supplied to the actuator without significantly changing the vehicle speed. It can be satisfactorily supplied, and thereby the steering stability and riding comfort of the vehicle can be well controlled.

Since it is not necessary to set the pump discharge flow rate to a high level by using a high capacity pump, the working fluid consumption is small as when the vehicle runs on a good road without acceleration / deceleration or turning. In this situation, it is possible to reliably prevent the energy generated by the engine from being wasted by the pump and the resulting deterioration in fuel consumption.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a drive system control device for a vehicle equipped with an active suspension according to the present invention, for a single wheel.

FIG. 2 is a block diagram showing an integrated control device shown in FIG.

FIG. 3 is a flow chart showing pump output control achieved by the integrated control device shown in FIGS. 1 and 2.

FIG. 4 is an engine speed Ne and a gear stage S of an automatic transmission.
5 is a graph showing the relationship between the vehicle speed and the vehicle speed V.

FIG. 5 is a time chart showing an example of a change in the engine speed Ne during one downshift of the automatic transmission.

FIG. 6 shows the engine speed Ne and the gear stage S of the automatic transmission.
7 is a graph showing the relationship between the vehicle speed V and the vehicle speed V when two downshifts are performed.

FIG. 7 is a time chart showing an example of changes in the engine speed Ne when the automatic transmission is downshifted by two gears.

FIG. 8 is a graph showing a relationship between an engine speed Ne and a discharge flow rate Q of a pump incorporated in an active suspension.

[Explanation of symbols]

 12 ... Wheel 16 ... Actuator 24 ... Gas spring 30 ... Flow control valve 36 ... Reservoir 38 ... Pump 40 ... Engine 52 ... Vehicle height sensor 56 ... Automatic transmission 60 ... Engine control device 62 ... Automatic transmission control device 64 ... Integrated control Device 72 ... Microcomputer

Claims (1)

[Claims] 1. An actuator having an engine and an automatic transmission, which is provided corresponding to each wheel and increases or decreases the vehicle height of a corresponding portion by supplying and discharging a working fluid, and a pump driven by the engine. A working fluid supply source including a working fluid supply source, and a control valve for controlling supply and discharge of working fluid to and from each actuator from the working fluid supply source. Supply / discharge amount estimating means for estimating the supply / discharge amount per unit time, and a pump for shifting down the shift stage of the automatic transmission and increasing the engine speed when the supply / discharge amount is equal to or more than a predetermined value. A drive system controller having an output controller.