Method and system for assisting the start-up of a motor vehicle

Abstract

The present invention provides start-up assistance for a motor vehicle having braking equipment which, in the stationary state of the mo-or vehicle, automatically or under the control of a vehicle driver summons up braking forces needed for the stationary state. To assist start-up of the motor vehicle through a reduction of the braking forces generated in the stationary state, a start-up request of a vehicle driver is determined when defined conditions, which are to be met for start-up of the motor vehicle, exist in the stationary state. Once a start-up request has been recognized, the operating state of the motor vehicle is checked until an operating state required for start-up exists. Once such an operating state is reached, the braking equipment of the motor vehicle is controlled in such a way that its braking forces generated in the stationary state are reduced to allow start-up of the vehicle.

Description

DESCRIPTION[0001] 1. Field of the Invention[0002] The present invention relates to a method and a system for assisting the start-up of a motor vehicle. In particular, the present invention relates to a method and a system which during start-up of a motor vehicle control braking equipment, which is activated in the stationary state of the motor vehicle, so as to assist and allow the start-up.[0003] 2. Background of the Invention[0004] The braking equipment or parts of the braking equipment of a motor vehicle are usually operated also in the stationary state of the motor vehicle in order to maintain the stationary state of the latter. Generally, for said purpose use is made of a parking brake, which is typically actuated by a vehicle driver, or of braking equipment which in a controlled manner generates braking forces required for the stationary state.[0005] To start up the motor vehicle, it is necessary to reduce the braking forces generated in the stationary state.[0006] 3. Prior Ar...

AI Technical Summary

Benefits of technology

[0012] The object of the present invention is to provide a method and a system for assisting the start-up of a motor vehicle having braking equipment activated in the stationary state, which method and system assist and render more comfortable the transitions from a stationary to a travelling state, wherein the previously described drawbacks of prior art are overcome.BRIEF DESCRIPTIONS OF THE INVENTION

[0026] When controlling the braking equipment for leaving the stationary state it is further provided that the motor vehicle is controlled in such a manner that start-up takes place as jerk-free as possible and without increased strain on or damage of the braking equipment, in particular the brake linings. For controlling the operating states of the motor vehicle occurring during control of the braking equipment, it is possible to resort to already existing systems, such as an engine management system. The control of the motor vehicle may during the control of the braking equipment for leaving the stationary state take place in dependence upon an operating state of the braking equipment in the stationary state, the detected startup parameters, the detected current operating state in the state of start-up, and a current operating state during the control of the braking equipment.

Problems solved by technology

This is the case, for example, when the vehicle is not started, the engine speed occasioned by the actuation of the accelerator pedal or the engine torque is insufficient to start the vehicle, and the like.

Thus, said known parking brake may lead to an unwanted release or to a release of the parking brake which makes it necessary for the vehicle driver during start-up of the motor vehicle to take additional measures to avoid undesirable driving states.

Said procedure has the drawback that the current engine torque, even when it corresponds to the required starting torque, does not provide any reliable indication about whether the motor vehicle is actually in a driving state required for start-up.

When in such cases the required starting torque is reached, the brake system is nevertheless deactivated with the result that an undesirable movement of the motor vehicle may occur.

This has the drawback that, while the torques of the driving wheels needed to open the valve are sufficient to keep the vehicle stationary particularly on an ascending gradient, they are not high enough actually to bring the motor vehicle from the stationary state to a travelling state.

A further drawback is that said procedure does not check whether the torques acting upon the driving wheels are generated by the engine or are attributable to other causes.

A general drawback of said start-up assistance is that the reduction--occasioned by opening of the valve--of braking forces summoned up in the stationary state is effected independently of the manner in which the motor vehicle is to be moved out of the stationary state.

This may lead to uncomfortable, jerky start-up phases, during which it may be necessary for the driver to take additional measures to achieve start-up of the motor vehicle in a desired manner.

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