Evaluation process and evaluation device for sensor output signals

• US 5,101,115 A
• Filed: 09/19/1989
• Issued: 03/31/1992
• Est. Priority Date: 09/02/1988
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Nitschke, Werner, Taufer, Peter, Drobny, Wolfgang, Weller, Hugo
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): GAFFIN, JEFFREY A
• Application Number:
  US07/409,111
• Time in Patent Office: 924 Days
• Field of Search: 307/9.1, 307/10.1, 280/734, 280/735, 280/801
• US Class Current: 307/10.1
• CPC Class Codes: B60R 2021/01322 comprising variable thresholds, e.g. depending from other collision parameters
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values

Abstract

In an evaluation process for output signals of an acceleration-sensitive sensor in restraint systems for vehicle occupants, the output signals of the sensor are picked up and evaluated periodically. In a normal, uncritical operating state the evaluation occurs after relatively long intervals of time. If indications suggest a critical operating state, that is, an accident, however the evaluation of the output signals of the sensor occurs at shorter intervals of time.

Claims

1. A method for controlling the release of a passenger restraint system in a motor vehicle comprising the following steps:

generating signals indicative of the acceleration of the motor vehicle;

measuring first time intervals, and comparing the acceleration signals or values indicative thereof to a threshold value upon expiration of each first time interval, the threshold value being indicative of a critical operating state of the motor vehicle; and

if the acceleration signals exceed the threshold value, measuring second time intervals which are shorter than the first time intervals, and evaluating the acceleration signals upon expiration of each second time interval to facilitate the quick release of the passenger restraint system in response to a vehicle collision.

2. A method as defined in claim 1, further comprising the following steps:

measuring the time that the acceleration signals exceed the threshold value and comparing the measured time to a predetermined time interval, and if the measured time exceeds the predetermined time interval, measuring the second time intervals which are shorter than the first time intervals, and evaluating the acceleration signals upon expiration of each second time interval.

3. A method as defined in claim 1, wherein

the acceleration signals are based on the slope of the tangent to the point marking the expiration of the respective time interval on a curve of the acceleration signals with respect to time, wherein the greater the slope, the greater is the deceleration of the motor vehicle.

4. An apparatus for controlling the release of a passenger restraint system in a motor vehicle, comprising:

at least one acceleration sensor adapted to be mounted on a motor vehicle and to generate output signals indicative of the acceleration of the motor vehicle;

an evaluating unit coupled to the acceleration sensor for evaluating the acceleration signals and controlling the release of the passenger restraint system in response thereto; and

a timing unit adapted to measure first time intervals and to transmit evaluation signals indicative of the expiration of each first time interval to the evaluating unit, the evaluating unit being adapted to evaluate the acceleration signals in response to the evaluation signals, the timing unit being further adapted to measure second time intervals in response to detecting a critical operating state of the motor vehicle, the critical operating state being based on the value of the acceleration signals exceeding a predetermined value, and to transmit evaluation signals indicative of the expiration of each second time interval to the evaluating unit, the second time intervals being shorter than the first time intervals, the evaluating unit thus being adapted to more frequently evaluate the acceleration signals and, thus, facilitate the quick release of the passenger restraint system when the vehicle is operating in a critical state.

5. An apparatus as defined in claim 4, further comprising:

first means coupled to the evaluating unit for measuring the amplitude of the acceleration signals; and

second means coupled to the first means for comparing the amplitude to a threshold amplitude value and for transmitting an alarm signal to the timing unit in response to the amplitude exceeding the threshold value, the timing unit being responsive to the alarm signal to measure the second time intervals and to transmit the evaluation signals to the evaluating unit in response to the expiration of the second time intervals.

6. An apparatus as defined in claim 5, wherein the evaluating unit is adapted to calculate the slope of the tangent to the point marking the expiration of the respective time interval on a curve of the acceleration signals with respect to time, wherein the greater the slope, the greater is the deceleration of the motor vehicle, and to control the release of the passenger restraint system based thereon.