Vehicle speed control system and method

Abstract

A system for controlling vehicle speed in accordance with a current value of vehicle set-speed. The system responds to user input to change the current value of vehicle set-speed to a different value and is configured to store the current value of set-speed in a memory as a stored set-speed and to change the current value of set-speed in dependence on the user input. The speedometer indicates both the current and stored set-speeds. The system can return the current value of vehicle set-speed to the stored set-speed upon receipt of a “resume” or other user command. The system can enter into a descent control mode that applies braking torque but no drive torque and can also enter into a full functionality mode that provides either drive or braking torque to maintain the vehicle at the set-speed.

Description

FIELD OF THE INVENTION[0001]The invention relates to a system for controlling the speed of a vehicle. In particular, but not exclusively, the invention relates to a system for controlling the speed of a land-based vehicle which is capable of driving in a variety of different and extreme terrains and conditions.BACKGROUND TO THE INVENTION[0002]In known vehicle speed control systems, typically referred to as cruise control systems, the vehicle speed is maintained on-road once set by the user without further intervention by the user so as to improve the driving experience for the user by reducing workload.[0003]The user selects a speed at which the vehicle is to be maintained, and the vehicle is maintained at that speed for as long as the user does not apply a brake or, in some systems, the clutch. The cruise control system takes its speed signal from the driveshaft or wheel speed sensors. When the brake or the clutch is depressed, the cruise control system is disabled so that the user...

AI Technical Summary

Benefits of technology

Enables continuous vehicle progress at low speeds in off-road conditions without user intervention, improving control and reducing driver workload by maintaining set speeds despite varying terrain and wheel slip events.

Problems solved by technology

In congested traffic conditions, however, where vehicle speed tends to vary widely, cruise control systems are ineffective, and especially where the systems are inoperable because of a minimum speed requirement.

Such systems are therefore ineffective in certain driving conditions (e.g. low speed) and are set to be automatically disabled in circumstances in which a user may not consider it to be desirable to do so.

Accordingly, they are not well suited to maintaining vehicle progress when driving in off road conditions where such events may be relatively common.

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