Combined power steering and variable suspension control arrangement

• US 4,922,427 A
• Filed: 11/27/1987
• Issued: 05/01/1990
• Est. Priority Date: 11/28/1986
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yokote, Masatsugu, Ito, Hideo, Kawagoe, Kenji, Kuroki, Junsuke
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/125,952
• Time in Patent Office: 886 Days
• Field of Search: 364/424.05, 180/79.1, 280/6 R, 280/6 H, 280/707, 280/DIG. 1
• US Class Current: 701/48
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B62D 6/06 responsive only to vehicle vibration dampening arrangements steering dampers for cycles B62K21/08

Abstract

A suspension and steering control system includes a mode selection which enables a normal mode wherein the suspension is conditioned to produce a soft damping and sufficient power assistance to the steering to produce light steering characteristics and a sporty mode wherein the suspension is conditioned to produce a firm ride and the power assistance to the steering lowered to produce heavier steering characteritics. The system further includes an arrangement for sensing parameters which are related to the attitude of the vehicle and/or the suspension thereof and for (a) during the normal mode, temporarily conditioning the suspension to produce the firm ride characteristics if the attitude of the vehicle is apt to change beyond a predetermined amount, and for (b), during the sporty mode, temporarily conditioning the suspension to produce the soft ride in the event that no substantial changes in the vehicle attitude related parameters are sensed.

Claims

1. A vehicle system comprising:

a power assisted steering system, said steering system including a valve for varying a degree of steering assist produced;

a suspension including a damper, said damper selectively producing a first damping characteristic and a second harder damping characteristic;

sensor means for sensing parameters which effect the vehicle suspension and an attitude of the vehicle;

a mode selector, said mode selector being selectively adjustable to;

produce a first signal indicative of a demand for a first mode wherein the steering power assist is raised to a level at which a first steering characteristic is produced and wherein the suspension is set to produce said first suspension characteristic, and

produce a second signal indicative of a demand that the steering power assist be lowered from the level at which said first steering characteristic is produced to a level whereat a second steering characteristic, which is heavier than the first steering characteristic produced, and for the suspension to be conditioned to produce said second suspension characteristic; and

a control device responsive to said sensor means and said mode selector, said control device including a circuit which senses the change in vehicle attitude and which, in the event that, the mode selector is set to produce said first signal and the sensor means indicates that the attitude of the vehicle is subject to a tendency to change beyond a predetermined amount, said circuit temporarily conditions the suspension to produce said second suspension characteristic until the tendency of the vehicle attitude to change beyond more than said predetermined amount disappears.

2. A system as claimed in claim 1, wherein said circuit is further constructed such that when the mode selector is set to produce said second signal and the sensor means indicates that the attitude of the vehicle is not changing by more than said predetermined amount, the circuit temporarily conditions the suspension to produce said first suspension characteristic until the attitude is subject to a tendency to change more than said predetermined amount.

3. A method of controlling a power steering and a variable suspension comprising the steps of:

selecting one of first and second modes;

controlling a power steering system to produce a first level of steering assist when said first mode is selected and to produce a second level of steering assist which is lower than the first one when the second mode is selected;

controlling a variable suspension system to normally produce a first soft suspension characteristic when said first mode is selected and to normally produce a second hard characteristic when the second mode is selected;

sensing parameters which influence the attitude of the vehicle;

determining if the attitude of the vehicle is tending to change by more than a predetermined amount;

temporarily conditioning said suspension to produce said second hard suspension characteristic when the first mode is selected and said determining step indicates that the attitude of the vehicle is tending to change by more than said predetermined amount; and

maintaining the said hard suspension characteristic until said determining step indicates that the attitude is not changing by more than said predetermined amount.

4. A method as claimed in claim 3, further comprising the steps of:

temporarily conditioning said suspension to produce said first suspension characteristic when said second mode is selected and said determining step indicates that the attitude of the vehicle is not changing by more than said predetermined amount; and

maintaining the suspension in said first soft suspension characteristic until said determining step indicates that attitude of said vehicle is tending to change in excess of said predetermined amount.

5. A vehicle system comprising:

a power assisted steering system, said steering system including a valve, said valve being arranged to selectively vary the level of power assist produced between a first level wherein the power assist is high and a second level wherein a reduced amount of power assist is produced;

a suspension including a damper, said damper being selectively conditionable to produce soft and hard damping characteristics;

sensor means for sensing parameters which effect the vehicle suspension and an attitude of the vehicle;

a mode selector, said mode selector being selectively conditionable to;

produce a first signal which induces said valve to produce the first high level of assist level and induce said damper to produce said soft suspension characteristic, and

produce a second signal which induces said valve to produce said second reduced level of assist and for inducing said damper to produce said hard suspension characteristic; and

a control device responsive to said sensor means and said mode selector, said control device including a circuit which senses the change in vehicle attitude and which, when the mode selector is set to produce said first signal and the sensor means indicates that the attitude of the vehicle is subject to a tendency to change beyond a predetermined amount, temporarily conditions said damper to produce said hard suspension characteristic until the tendency of the vehicle attitude to change beyond more than said predetermined amount disappears.

6. A vehicle system comprising:

a power assisted steering system, said steering system including a valve for varying a degree of steering assist produced;

a suspension including a damper, said damper selectively producing a first damping characteristic and a second harder damping characteristic;

sensor means for sensing parameters which effect the vehicle suspension and an attitude of the vehicle;

a mode selector, said mode selector being selectively adjustable to;

produce a first signal indicative of a demand for a first mode wherein the steering power assist is raised to a level at which a first steering characteristic is produced and wherein the suspension is set to produce said first suspension characteristic, and

produce a second signal indicative of a demand that the steering power assist be lowered from the level at which said first steering characteristic is produced to a level whereat a second steering characteristic, which is heavier than the first steering characteristic is produced, and for the suspension to be conditioned to produce said second suspension characteristic; and

a control device responsive to said sensor means and said mode selector, said control device including a circuit which senses the change in the vehicle attitude and which, in the event that, the mode selector is set to produce said first signal and the sensor means indicates that the attitude of the vehicle is subject to a tendency to change beyond a predetermined amount, said circuit maintains the level of power assist produced at said level at which said first steering characteristic is produced and temporarily conditions the suspension to produce said second suspension characteristic until the tendency of the vehicle attitude to change beyond more than said predetermined amount disappears;

said circuit further being constructed such that when the mode selector is set to produce said second signal and the sensor means indicates that the attitude of the vehicle is not changing by more than said predetermined amount, the circuit maintains the level of power assist produced at said level at which said second steering characteristic is produced and temporarily conditions the suspension to produce said first suspension characteristic until the attitude is subject to a tendency to change more than said predetermined amount.

7. A vehicle system comprising:

a power assisted steering system, said steering system including a valve for varying a degree of steering assist produced;

a suspension including a damper, said damper selectively producing a first damping characteristic and a second harder damping characteristic;

sensor means for sensing parameters which effect the vehicle suspension and an attitude of the vehicle;

a mode selector, said mode selector being selectively adjustable to;

produce a first signal indicative of a demand for a first mode wherein the steering power assist is raised to a level at which a first steering characteristic is produced and wherein the suspension is set to produce said first suspension characteristic, and

produce a second signal indicative of a demand that the steering power assist be lowered from the level at which said first steering characteristic is produced to a level whereat a second steering characteristic is produced, and for the suspension to be conditioned to produce said second suspension characteristic; and

a control device responsive to said sensor means and said mode selector, said control device including a circuit which senses the change in the vehicle attitude and which when the mode selector is set to produce said second signal and the sensor means indicates that the attitude of the vehicle is not changing by more than said predetermined amount, the circuit temporarily conditions the suspension to produce said first suspension characteristic until the attitude is subject to a tendency to change more than said predetermined amount.

8. A method of controlling a power steering and a variable suspension comprising the steps of:

selecting one of first and second modes;

controlling a power steering system to produce a first level of steering assist when said first mode is selected and produce a second level of steering assist which is lower than the first one when the second mode is selected;

sensing parameters which influence the attitude of the vehicle;

determining if the attitude of the vehicle is tending to change by more than a predetermined amount;

temporarily conditioning said suspension to produce a hard suspension characteristic when the first mode is selected and said determining step indicates that attitude of the vehicle is tending to change by more than said predetermined amount;

maintaining said hard suspension characteristic until said determining step indicates that the attitude is not changing by more than said predetermined amount;

temporarily conditioning said suspension to produce said first a soft suspension characteristic when said second mode is selected and said determining step indicates that the attitude of the vehicle is not changing by more than said predetermined amount; and

maintaining the suspension in said soft suspension characteristic until said determining step indicates that the attitude of said vehicle is tending to change in excess of said predetermined amount.

9. A method of controlling a power steering and a variable suspension comprising the steps of:

selecting one of first and second modes;

controlling a power steering system to produce a first level of steering assist when said first mode is selected and produce a second level of steering assist which is lower than the first one when the second mode is selected;

sensing parameters which influence the attitude of the vehicle;

determining if the attitude of the vehicle is tending to change by more than a predetermined amount;

temporarily conditioning said suspension to produce a soft suspension characteristic when said second mode is selected and said determining step indicates that the attitude of the vehicle is not changing by more than said predetermined amount; and

maintaining the suspension in said soft suspension characteristic until said determining step indicates that the attitude of said vehicle is tending to change in excess of said predetermined amount.