Method for Calculating the Low Pressure in the Servobrake of a Vehicle Comprising an Otto Engine
The subject of the invention concerns at least a method for the determination, without a pressure sensor, of a pressure in a brake booster actuated with an actuator for a motor vehicle with engine system including an inlet pipe subjected to inlet pipe pressure, for optimized performance of a braking operation, including the steps of: detecting the driving situation and simulating the pressure (BP_SIM) as a function of the driving situation, and a device for boosting the brake pressure in an Otto engine-driven motor vehicle with an actuator and a vacuum-dependent pressure-boosting device coupled to the actuator, wherein the pressure-boosting device is designed without a vacuum sensor, and a brake booster, with means for carrying out the method.
1 . Method for the determination, without a pressure sensor, of a pressure in a brake booster actuated with an actuator for a motor vehicle with engine system including an inlet pipe subjected to inlet pipe pressure, for optimized performance of a braking operation, comprising the steps of:
detecting the driving situation; and
simulating the pressure (BP_SIM) as a function of the driving situation.
2 . Method according to claim 1 , wherein detection of the driving situation comprises the steps of:
ascertaining the initial value of the pressure (BP_SIM);
detecting and storing variable driving situation parameters; and
defining fixed driving situation parameters.
3 . Method according to claim 1 , wherein simulation of the pressure (BP_SIM) comprising the steps of:
initializing the pressure (BP_SIM);
checking and signal whether an actuator is actuated;
calculating the pressure (BP_SIM) as a function of the driving situation parameters and actuation of the actuator (LV_BLS, LV_BTS); and
fixing the pressure (BP_SIM) as a function of the calculation made.
4 . Method according to claim 1 , wherein the driving situation parameters are selected from the group consisting of:
an inlet pipe pressure (MAP), a brake light switch signal (LV_BLS), a brake switch signal (LV_BTS), a vehicle speed (VS), an ambient pressure (AMP), a vehicle acceleration (ACC), a torque (TQ), an engine speed (N), or a gear (GEAR).
5 . Method according to claim 1 , wherein, upon actuation of the actuator and hence indirectly the brake and/or brake light switch, the vehicle speed is monitored and at least one variable driving situation parameter is calculated for the optimized braking operation.
6 . Method according to claim 5 , wherein the variable driving situation parameter is the deceleration.
7 . Method according to claim 6 , wherein, when the brake switch is actuated, the pressure (BP_SIM) is increased as a function of the deceleration.
8 . Method according to claim 3 , wherein a fixed driving situation parameter is the value for deceleration in case of hard braking and is predetermined.
9 . Method according to claim 3 , wherein, when the vehicle speed falls below a limit value, upon activation of the actuator a pressure increase corresponding to hard braking is simulated.
10 . Method according to claim 9 , wherein, when the pressure (BP_SIM) in the brake booster is greater than the inlet pipe pressure in the inlet pipe, the pressure (BP_SIM) is reduced to the inlet pipe pressure level.
11 - 13 . (canceled)