Abstract: A vehicle roll control system uses two accelerometers (38, 40) on the vehicle to detect body roll and then filters out higher frequency roll movements as indicative of a rough road surface. The system also monitors vehicle speed, and increases roll stiffness in response to measured increase in vehicle speed, but decreases roll stiffness in response to detected rough road surfaces.

Abstract: A vehicle roll control system uses two accelerometers (38, 40) on the vehicle to detect body roll and then filters out higher frequency roll movements as indicative of a rough road surface. The system also monitors vehicle speed, and increases roll stiffness in response to measured increase in vehicle speed, but decreases roll stiffness in response to detected rough road surfaces.

Abstract: A vehicle roll control system uses two accelerometers (38, 40) on the vehicle to detect body roll and then filters out higher frequency roll movements as indicative of a rough road surface. The system also monitors vehicle speed, and increases roll stiffness in response to measured increase in vehicle speed, but decreases roll stiffness in response to detected rough road surfaces.

Abstract: An active vehicle roll control system is disclosed in which a roll bar (22) has two halves (22a, 22b) which can be rotated relative to each other by a control unit (26) in order to actively control vehicle roll. The control unit (26) receives signals from lateral accelerometers (29, 30). In order to determine accurately when the vehicle is experiencing zero lateral acceleration, the control unit (26) averages the signal from each accelerometer (29, 30) continuously and uses the average signal as an indication of the straight ahead position. The averaging algorithm defines a window of low lateral accelerations to be used, and a gain to be applied to the acceleration signals, each of which is speed dependent so that the averaging process is not affected by abnormal vehicle movements.

Abstract: In an active roll control system for a vehicle, anti-roll bars (26, 30) are provided with actuators (28, 32) which can provide a torque in the anti-roll bars to control vehicle body roll. Under certain cornering conditions when the vehicle is liable to over-steer, the pressure supply to the actuators is pulsed so that the front wheels of the vehicle tend to break away more easily, thereby reducing over-steer.

Abstract: A vehicle suspension system control unit (40) is arranged to determine from a lateral accelerometer (42) and vehicle speed sensor (44) when the vehicle is executing a series of opposite turns in a slalom type manner which are likely to cause a build-up of body roll. In this situation the roll control system is modified from a regime in which some body roll is allowed, to a regime in which body roll is substantially prevented thereby to prevent the build up of body roll during slalom type maneuvers.

Abstract: A vehicle roll control system is disclosed in which a pair of vertically spaced lateral accelerometers (28, 30) are used to measure lateral acceleration as well as vehicle body roll and to measure cornering acceleration by measuring the lateral acceleration not produced by body roll.

Abstract: An active vehicle roll control system is disclosed in which a roll bar (22) has two halves (22a, 22b) which can be locked together to allow the system to operate passively. A sensing system based on a lateral accelerometer and vehicle speed sensor is arranged to detect when the vehicle is on a side slope and to put the roll control system into the passive mode.

Abstract: A hydraulic actuator for a vehicle roll control system includes a fluid pressure transducer 28, housed in a valve block 16, the output characteristic of which is temperature dependent. In order to correct for this the temperature of the fluid is monitored. This is done by monitoring the duty ratio of the pulse width modulated driving signal to a control valve 22 in the block, which varies with temperature to produce a constant total current.

Abstract: A vehicle suspension system comprising a hydraulic roll control actuator 4 controlled by a hydraulic circuit 10. The circuit 10 includes a valve block having a pressure line 18a supplied by a pump 12 and a return line 20a, and a pressure control valve 22 for controlling the flow of hydraulic fluid from the pressure line 18a to the return line 20 to control the hydraulic pressure drop between them. Two actuation control valves 24, 26 allow connection of the actuators between the pressure and return lines to control the actuating force produced by the actuators. A control unit 30 is arranged to connect the actuators 4 only when the desired actuating force is greater than a minimum value corresponding to a minimum pressure drop which can be produced by the pressure control valve 22, and to determine the minimum pressure drop from measurement of the temperature of a part of the hydraulic system.

Abstract: A vehicle roll stabilizing system uses front and rear stabilizer assemblies (23, 24) which each use a stabilizer bar (24) and a hydraulic ram (33, 35) to resist vehicle roll. Selector valves (43, 44) select pressure from a pump (36) or return hydraulic oil to a reservoir (37) according to 4 modes, two of which the selector valve is in an on and an off condition, respectively. A diverter valve (73) operates to control the pump pressure in proportion to lateral acceleration to provide an actuator effort which resists roll during vehicle cornering. This effort is provided up to a limit equivalent to a lateral acceleration of approximately 0.4 g after which roll is allowed to increase, either by keeping the pump pressure (and hence effort) constant or by increasing the pump pressure at a reduced rate.

Abstract: The security system comprises a coil (34) close to the vehicle ignition lock (38), a control unit (10) for energizing the coil and a transponder which comprises a coil (32), a transistor (30) and a transmitter (24) and a power supply (26). In use the coil (32) picks up a conventional alternating magnetic signal emitted by the coil (34), and provides sufficient power to activate the transistor (30) which connects the power supply (26) to the transmitter (24) causing it to transmit an enabling signal to the control unit. The control unit may be programmed to re-mobilize the vehicle engine on receiving of the correct signal.