Fluid-pressure and analogous brake systems – Speed-controlled – And traction control
Patent
1998-03-02
2000-01-11
Oberleitner, Robert J.
Fluid-pressure and analogous brake systems
Speed-controlled
And traction control
3031161, 303191, 303 9, B60T 824
Patent
active
06012783&
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention pertains to a process for operating a slippage-controlled motor vehicle braking system for controlling driving dynamics, in which the desired pressure at the motor vehicle brake to be controlled is set.
BACKGROUND OF THE INVENTION
In order to shorten the control time, particularly in case of high viscosity of the pressure medium, it was proposed in P 44 25 578.0 (P 7697) to turn on a supplemental pressure medium source at the beginning of the braking process which quickly makes available the required pressure of the pressure medium. As described in detail in the aforesaid P 44 25 578.0, such a measure offers the great advantage that the response of the regulation at the brakes can be considerably accelerated, even in the case of high viscosity of the pressure medium and thus considerable pressure losses due to the sluggish flow of the pressure medium inside the pressure lines.
It has turned out to be a certain disadvantage, however, that turning on such a supplemental pressure medium source can cause noise that may distract the driver precisely at the moment in time in which he is in a critical driving situation in need of regulation.
The object of the invention is to connect the supplemental pressure medium source to the control loop only if this is actually necessary to accelerate the regulation process.
This object is achieved, according to the invention, by turning on the supplemental pressure medium source as a function of a sufficiently large deviation from the desired value of the regulation parameter for driving dynamics, and a second factor which constitutes a measurement of whether turning on the pressure medium source is necessary for increasing the regulation rate under the environmental conditions. The invention brings the additional advantage that the supplemental pressure medium source is not operated unnecessarily and thus is under less mechanical stress, which contributes to increasing its reliability and service life.
In practice, it has proven particularly reasonable to make the connection of the supplemental pressure medium source dependent on the viscosity of the pressure medium. One parameter affecting the viscosity is the temperature of the pressure medium itself, so that it is advisable as an advantageous refinement of the invention to make connection dependent on the pressure medium temperature.
In order to save on additional sensors for measuring temperatures, the existing engine intake air temperature sensor can be used for estimating the temperature of the pressure medium.
Another possibility of estimating the temperature of the pressure medium consists of measuring wheel and vehicle response times according to the latter principle, the regulation behavior is evaluated for estimating the temperature.
In a preferred embodiment, the supplemental pressure medium source is activated only if the temperature of the pressure medium falls below a pre-determined temperature.
A particularly advantageous refinement of the invention is presented if the connection of the supplemental pressure medium source is made dependent on an additional parameter which corresponds to the gradient of the deviation of the actual value from the desired value of the control parameter. In other words, if the actual value of the driving dynamics parameter, such as the yaw angle velocity, differs only slightly from the desired set value, then it is not necessary for the regulation to take effect abruptly due to turning on the supplemental pressure medium source. Instead, it is then sufficient for the regulation to be operated only with the aid of the supply pump as a pressure medium source. The advantage is that in this way the regulation not only operates rather quietly, but also corrects the driving behavior of the vehicle more gently. This further contributes to the driving comfort of the operator. It is particularly advisable here as a refinement of the invention to make turning on the supplemental source dependent on the gradient of the difference of (one of the) following
REFERENCES:
patent: 4477124 (1984-10-01), Watanabe
patent: 5217284 (1993-06-01), Willmann
patent: 5275476 (1994-01-01), Maisch
patent: 5480221 (1996-01-01), Morita et al.
patent: 5584543 (1996-12-01), Sawada
patent: 5586814 (1996-12-01), Steiner
patent: 5636907 (1997-06-01), Okazaki et al.
patent: 5694321 (1997-12-01), Eckert et al.
patent: 5769509 (1998-06-01), Feigel et al.
Graber Johannes
Krull Thomas
Schwarzer Paul
ITT Manufacturing Enterprises Inc.
Oberleitner Robert J.
Williams Thomas J.
LandOfFree
Process for the temperature-dependant actuation of an additional does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the temperature-dependant actuation of an additional, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the temperature-dependant actuation of an additional will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1456745