US 5,189,615 AGranted

Semi-active suspension control

AssigneeRobert Bosch GmbH

InventorsErich Rubel, Karl-Heinz Haegele, Michael Panther, Klaus Gatter

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Abstract

The invention concerns a method and a device for the suspension control of vehicles, in particular motorcars and commercial vehicles, with the following steps: Sensory ascertainment of the dynamic rolling condition and processing of the established rolling condition data, to generate a control signal for a semi-active damper, preferably one allocated to each wheel of the vehicle, the damping force of which is adjustable in certain situations which are dependent on the driving condition, to as small a value as possible. It is suggested that the semi-active damper, depending on the control signal and the actual value of the damper force is set in substitution for an active damper function which though desired with regard to the prevailing operating point, is not however achievable, this substitute setting being made with maximum hardness or maximum softness.

Claims7

Dependent claims

A process for the undercarriage control of vehicles, particularly of passenger cars and trucks, the vehicles having a plurality of semiactive shock absorbers arranged between the vehicle superstructure and the wheels, each semiactive shock absorber including a cylinder subdivided into two working spaces by a piston wherein a fluid may flow through a variable valve from one working space to the other, each valve being adjustable dependant on factors of absorber force and piston velocity when a factor pair falls within specific limits and each valve being adjustable according to maximally soft or maximally hard shock absorber settings when the factors fall outside said specific limits, said process comprising the steps of:

determining the piston velocity of the shock absorbers;
determining the dynamic state of vehicular travel and processing the determined state of travel for calculation of factors of shock absorber force and piston velocity for each shock absorber to provide a momentarily optimal shock absorber force;
and
adjusting each valve according to the momentarily optimal shock absorber force and the corresponding factor pair of calculated shock absorber force and piston velocity, wherein:
(1) if the corresponding factor pair of calculated shock absorber force and piston velocity falls within said specific limits, the corresponding valve is adjusted dependent on the piston velocity, and
(2) if the corresponding factor pair of calculated shock absorber force and piston velocity falls outside said specific limits, the corresponding valve is adjusted to said maximally soft or maximally hard shock absorber setting depending on which of the two shock absorber settings most closely approximates the effect of the momentarily optimal shock absorber force applied to the determined dynamic state of vehicular travel.

3 more elements

A device for suspension control on vehicles, particularly of passenger cars and trucks, the vehicles having a superstructure and wheels, said suspension control device comprising:

a plurality of semiactive shock absorbers, each said semiactive shock absorber including a cylinder adapted to contain a fluid and being subdivided into two working spaces by a piston, said piston including a variable valve for fluid communication from one working space to the other, each said variable valve being adjustable depending on a factor pair of absorber force and piston velocity when said factor pair falls within specific limits and each said variable valve being adjustable according to maximally soft or maximally hard shock absorber settings when the factor pair falls outside said specific limits;
and
means for adjusting said variable valve, said adjusting means comprising means for determining the piston velocity of said shock absorbers, means for determining the dynamic state of vehicular travel, and means for calculating factors of shock absorber force and piston velocity for each said shock absorber to provide a momentarily optimal shock absorber force, said adjusting means controlling each said variable valve according to the momentarily optimal shock absorber force and said corresponding factor pair of calculated shock absorber force and piston velocity, said adjusting means operating such that:
(1) if said corresponding factor pair of calculated shock absorber force and piston velocity falls within said specific limits, said adjusting means adjusts said corresponding variable valve dependent on the piston velocity, and
(2) if said corresponding factor pair of calculated shock absorber force and piston velocity falls outside said specific limits, said adjusting means adjusts said corresponding variable valve to said maximally soft or maximally hard shock absorber settings most closely approximates the effect of the momentarily optimal shock absorber force applied to the determined state of vehicular travel.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/654,641Filed 14 Feb 1991
Priority: DE 392132429 Jun 1989
Granted: 23 Feb 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

B60G 17/08
Characteristics of dampers , e.g. mechanical dampers: characteristics of fluid dampers
B60G 17/018
The regulating means comprising electric or electronic elements: characterised by the use of a specific signal treatment or control method
B60G 2202/24
Type of damper: fluid damper
B60G 2204/80
Indexing codes related to suspensions per se or to auxiliary parts: interactive suspensions; arrangement affecting more than one suspension unit