DECELERATION WARNING DEVICE AND METHOD FOR A MOTOR VEHICLE

Abstract

The invention relates to a deceleration warning device for reducing rear-end collisions in road traffic, comprising: means (1) for detecting a longitudinal acceleration value a;a control device (3a; 3b; 3c; 3d) which is designed to receive the longitudinal acceleration value a at one of its inputs and to calculate an acceleration limit value upon exceeding of which a warning signal is emitted, the calculation of the acceleration limit value incorporating input parameters P,a filter device (2a; 2b) being interposed between the means (1) for detecting a longitudinal acceleration value and the control device, anddisplay means for displaying an alarm state when the control device emits a warning signal.

Description

Further advantageous embodiments of the invention are disclosed in the dependent claims and in the following description of the figures, in which:

FIG. 1 is a schematic representation of the components and signal flows of an embodiment of the device according to the invention, and

FIG. 2 is a block diagram of an exemplary embodiment of an algorithm for implementing the method according to the invention to activate a warning signal for the reduction of rear-end collisions in road traffic.

Claims

1. A deceleration warning device for reducing rear-end collisions in road traffic, comprising: means (1) for detecting a longitudinal acceleration value a;a control device (3a, 3b, 3c, 3d) which receives the longitudinal acceleration value a at one of its inputs and detects an acceleration limit value the exceeding of which prompts a warning signal to be emitted, the detection of the acceleration limit value incorporating input parameters P, wherein a stage (3a) includes a “No function” level (10), a “Limited function” level (12) and a “Normal function” level (14), a transition to or from a “Deceleration warning device active” state (16) to or from a “Deceleration warning device inactive” state (18) being executed in the “Limited function” level (12) and in the “Normal function” level (14) as a function of momentary input parameters P,a filter device (2a, 2b) being interposed between the means (1) for detecting the longitudinal acceleration value and the control device, anddisplay means for displaying an alarm state when the control device emits a warning signal.

2. A deceleration warning device as claimed in claim 1, whereinthe control device is additionally designed to terminate the emitting of the warning signal after a time T, T being determined as a function of the further behavior of the driver, change in the acceleration values, vehicle speed and/or elapsed time since the switching on of the deceleration warning system.

3. A deceleration warning device as claimed in claim 1 or 2, whereinthe control device has inputs for receiving signals of a brake control system and is designed to calculate the acceleration limit value while taking account of the signals of the brake control system.

4. A deceleration warning device as claimed in claim 3, whereinthe control device is designed to measure the duration t of activation of the brake control system and to take account of the signal of the brake control system only if the duration t exceeds a limit value.

5. A deceleration warning device as claimed in claim 3 or 4, whereinthe control device is designed to ignore the signals of the brake control system if the brake control system acts on only one of the two driven wheels.

6. A deceleration warning device as claimed in any one of the preceding claims, whereinthe control device is designed to receive a signal regarding the activation state of a brake assist system of the vehicle and to take account thereof in calculating the acceleration limit value.

7. A deceleration warning device as claimed in any one of the preceding claims, whereinthe means (1) for detecting a longitudinal acceleration value a include wheel speed sensors.

8. A deceleration warning device as claimed in any one of the preceding claims, whereinthe control device is designed to adapt the acceleration limit value using a statistical mean value of the longitudinal and lateral acceleration values of a defined past time period.

9. A method for activating a warning signal to reduce rear-end collisions in road traffic, in particular with a deceleration warning device as claimed in any one of the preceding claims, comprising the following steps: a) detecting a longitudinal acceleration value a;b) calculating an acceleration limit value upon exceeding of which a warning signal is emitted, the calculation of the acceleration limit value incorporating input parameters P; wherein a stage (3a) includes a “No function” level (10), a “Limited function” level (12) and a “Normal function” level (14), a transition to or from a “Deceleration warning device active” state (16) to or from a “Deceleration warning device inactive” state (18) being executed in the “Limited function” level (12) and in the “Normal function” level (14) as a function of momentary input parameters P,c) interposing a filter device (2a; 2b) between the means (1) for detecting a longitudinal acceleration value and the control device, andd) activating display means for displaying an alarm state if a warning signal is present.