Interrelated power delivery controls – including engine control – Brake control – Decreasing fluid energy input to engine actuates brake
Reexamination Certificate
2001-08-31
2003-04-29
Parekh, Ankur (Department: 3681)
Interrelated power delivery controls, including engine control
Brake control
Decreasing fluid energy input to engine actuates brake
C477S200000, C477S187000
Reexamination Certificate
active
06554744
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an apparatus and a method of controlling the road speed of a motor vehicle.
In modern motor vehicles the road speed is usually controlled by means of a pedal, also known as an accelerator pedal, which is biased counter to its actuating direction into an inoperative position and through the actuation of which the drive torque and/or the drive power of the motor vehicle engine may be increased. When the driver of the motor vehicle wishes to lower the road speed, he reduces the actuating force exerted on the accelerator pedal in order to move the accelerator pedal back towards, or fully into, its inoperative position. If this is not sufficient to achieve the desired lowering of the road speed, the driver actuates a brake pedal, which is usually likewise provided in the motor vehicle.
From DE-A-24 20 252 an accelerator pedal arrangement for motor vehicles is known, which in the unloaded state of the accelerator pedal activates a parking brake. Upon actuation of the accelerator pedal the parking brake is released.
SUMMARY OF THE INVENTION
The object of the invention is to indicate an apparatus and a method, which simplify control of the road speed of a motor vehicle.
Proceeding from the initially described apparatus comprising a braking-force generator for controlling the road speed of a motor vehicle, said object is achieved according to the invention in that the braking-force generator builds up the predetermined braking force in a controlled manner when the accelerator pedal reaches its inoperative position and/or reduces the built-up braking force in a controlled manner when the accelerator pedal leaves its inoperative position. The predetermined braking force is therefore not made available abruptly but brought up e.g. according to a preselected ramp function. In an analogous manner, the built-up braking force is preferably reduced in a controlled manner when the accelerator pedal leaves its inoperative position.
According to an alternative of the apparatus according to the invention the device for detecting the inoperative position of the accelerator pedal, upon a movement of the accelerator pedal from the inoperative position into the neutral position, causes the braking-force generator to reduce the predetermined braking force in accordance with the accelerator pedal movement and vice versa. In said manner, a driver may himself purposefully proportion the braking function of the apparatus according to the invention within the preselected limits, i.e. up to the predetermined braking force, by moving the accelerator pedal to a greater or lesser extent and/or more or less quickly between the inoperative position and the neutral position. Given such a form of construction, the device for detecting the inoperative position of the accelerator pedal takes the form of a displacement sensor, e.g. a displacement potentiometer.
According to a simple form of construction of the invention, the device for detecting the inoperative position of the accelerator pedal may be e.g. a switch, which in the inoperative position of the accelerator pedal is actuated by the latter and supplies the braking-force generator with a signal, in response to which the braking-force generator generates the predetermined braking force. The accelerator pedal is movable from its inoperative position into a neutral position, from which a further movement of the accelerator pedal counter to the spring bias, i.e. in actuating direction, leads to an increase of the drive torque and/or drive power of the motor vehicle engine.
Thus, according to the invention the acceleration function conventionally associated with the accelerator pedal is supplemented by an active braking function, wherein said two functions are separated from one another by the neutral position of the accelerator pedal. For specific applications it may however also be advantageous additionally to allow the said braking function to operate in actuating direction of the accelerator pedal slightly beyond the neutral position, e.g. for reliably preventing the vehicle from rolling backwards on a hill.
The apparatus according to the invention leads to considerably simplified vehicle control. For example, in stop-and-go traffic, instead of constantly having to transfer the right foot back and forth between accelerator pedal and brake pedal, the accelerator pedal now merely has to be eased back into the inoperative position. During downhill travel, when the engine braking action is frequently insufficient to achieve adequate deceleration of the vehicle, by simply easing back the accelerator pedal the brake system may be actuated with the predetermined braking force. Equally, for stopping on ascending gradients, according to the invention an easing of the accelerator pedal back into its inoperative position will in most cases be sufficient to prevent the vehicle from rolling backwards. A subsequent starting operation is also made more comfortable because, to release the brake and increase the engine drive torque, the accelerator pedal may be moved from the inoperative position quickly into the neutral position and beyond, without the usual practice of first having to transfer the right foot (from the brake pedal to the accelerator pedal), with the result that there is now virtually no opportunity for the vehicle to roll back. The apparatus according to the invention offers advantages also during emergency braking operations because the braking operation is already initiated by easing back the accelerator pedal and so is initiated more quickly than was previously usual. According to the invention the predetermined braking force is normally lower, in most cases even markedly lower, than the maximum possible braking force.
As already mentioned, the apparatus according to the invention is preferably designed in such a way that the braking-force generator in the neutral position of the accelerator makes no braking force or, at any rate, substantially no more braking force available.
In preferred embodiments of the apparatus according to the invention, the dimension of the predetermined braking force is varied in dependence upon specific parameters. For example, in one embodiment the predetermined braking force is increased as the road speed rises, and vice versa. In said manner, by means of the accelerator pedal an effective braking function is maintained also at higher road speeds.
In another embodiment, the magnitude of the predetermined braking force is varied in dependence upon the way in which the motor vehicle is moved. For example, for a sporty driving style the predetermined braking force is set higher than for a steady and economical driving style.
In yet another embodiment, the predetermined braking force is varied in dependence upon the speed at which the accelerator pedal is eased back. For a rapid release of the accelerator pedal the predetermined braking force is in said case set higher than for an only gradual easing back of the accelerator pedal. In said manner, the stopping distance of the vehicle in emergency braking situations may be markedly shortened.
In a further embodiment, the predetermined braking force is varied in dependence upon the inclination of the road on which the vehicle is situated. By inclination, here, is meant a descending or ascending gradient. The greater the ascending or descending gradient, the higher the predetermined braking force is set.
The described dependencies of the predetermined braking force may advantageously also be combined.
According to the invention, the braking-force generator may be a driver-independently actuable vacuum brake booster, a hydraulically or pneumatically actuable brake booster, a pressure accumulator or a pump, in particular the pump of a brake slip control system, which nowadays is already standard equipment in many motor vehicles. The braking-force generator may however also be an electrically operated actuator of a vehicle brake itself.
To help the driver of a motor vehicle to become accustomed to the apparatus according to the invent
Lucas Industries plc
MacMillan Sobanski & Todd LLC
Parekh Ankur
LandOfFree
Apparatus and method of controlling the road speed of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method of controlling the road speed of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method of controlling the road speed of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3060983