Actuation of an active device of a vehicle under braking
View Patent ↗Early actuation of an active device of a vehicle (e.g., a seat belt tensioner) is provided by applying rate of change of brake pressure to monitored brake pressure, so as to produce a modified brake pressure characteristic which is advanced in time. The active device is actuated at a brake pressure threshold.
1. A method of providing an actuation signal for an active device of a vehicle, the method comprising:
monitoring a change in the hydraulic fluid pressure in a hydraulic braking system of the vehicle;
calculating the rate of change of said hydraulic fluid pressure;
generating a boosted fluid pressure characteristic which is ahead of the change in hydraulic fluid pressure in time in dependence on the calculated rate of change; and
providing the actuation signal to control the actuation of the active device of the vehicle in dependence on the boosted fluid characteristic.
2. The method of claim 1 , wherein said boosted fluid pressure characteristic is generated from a look-up table by reference to said rate of change of fluid pressure.
3. The method of claim 1 , wherein said boosted fluid pressure characteristic is generated from an algorithm incorporating said rate of change of fluid pressure.
4. The method of claim 1 , further comprising the step of inhibiting the method when the fluid pressure in the braking system is below a pre-determined fluid pressure.
5. The method of claim 1 , further comprising the step of inhibiting the method when the rate of change of fluid pressure in the braking system is below a pre-determined rate of change of fluid pressure.
6. The method of claim 1 , further comprising the step of inhibiting the method when the fluid pressure in the braking system is decreasing.
7. The method of claim 1 , and including the further step of conditioning said boosted fluid pressure characteristic by reference to vehicle speed.
8. The method of claim 1 , including the steps of:
applying a threshold to said boosted fluid pressure characteristic, and
triggering the active device of the vehicle in response to said threshold being exceeded.
9. The method of claim 8 , wherein several successive thresholds are provided, each threshold indicating a successive condition of the active device of the vehicle.
10. The method of claim 1 , wherein the method is carried out using an electronic control system of the vehicle.
11. The method of claim 1 , wherein the active device is one or more of:
a seat belt tensioner,
an active seat bolster, and
a deployable aerodynamic device of the vehicle.
12. A system for controlling an actuation of an active device of a vehicle, the system comprising:
an electronic control unit configured to:
monitor a change in the hydraulic fluid pressure in a hydraulic braking system of the vehicle;
calculate the rate of change of said hydraulic fluid pressure;
generate a boosted fluid pressure characteristic which is ahead of the change in hydraulic fluid pressure in time in dependence on the calculated rate of change; and
provide an actuation signal to control the actuation of the active device in dependence on the boosted fluid characteristic.
13. A vehicle having a system for controlling an actuation of an active device, wherein the system comprises an electronic control unit configured to:
monitor a change in the hydraulic fluid pressure in a hydraulic braking system;
calculate the rate of change of said hydraulic fluid pressure;
generate a boosted fluid pressure characteristic which is ahead of the change in hydraulic fluid pressure in time in dependence on the calculated rate of change; and
provide an actuation signal to control the actuation of the active device in dependence on the boosted fluid characteristic.