Method and device for automatically releasing the automatic parking brake when starting
AssigneeRENAULT s.a.s.
InventorsPhilippe Deprez, Emmanuel Devaud, Philippe Planchon
Life of this patent
Estimating the term…
Abstract
A method and a device for automatically releasing an automatic parking brake at start-up. A transmitted torque estimation threshold value is determined that enables the vehicle movement to be balanced. Then, at start-up a loop for calculating the transmitted torque estimation is carried out so long as the calculated value does not exceed the threshold value. When the threshold is exceeded, an automatic parking brake-release command is produced.
Claims19
A method of assistance in starting a vehicle including a power unit and an automatic parking brake equipped with a mechanism of executing a command to release or deactivate the automatic parking brake, comprising, at least after one starting phase of the power unit:
- estimating a transmitted torque value required to balance the vehicle on a slope;
- executing in a loop an incremental calculation comprising:
- reading an effective average torque value (Cme) associated with a dynamic stage of the power unit,
- reading an engine speed value (Wm),
- calculating a time derivative of the engine speed,
- determining a moment of inertia of the power unit (Jmot) and calculating a load moment in a form of a product of the moment of inertia of the power unit by the time derivative of the engine speed, and
- determining an estimation of torque actually transmitted at a given moment (ECT) according to an equation:
- ECT=Cme−Jmot×dWm/dt,
- wherein the loop is executed while the estimation of the torque actually transmitted is insufficient to surpass the estimation of the transmitted torque required to balance the vehicle on the slope;
- and
- after the executing, producing a starting or deactivation command of the automatic parking brake.
A method of assistance in starting a vehicle including a power unit and an automatic parking brake equipped with a mechanism of executing a command to release or deactivate the automatic parking brake, comprising, at least after one starting phase of the power unit:
- estimating a transmitted torque value required to balance the vehicle on a slope;
- executing in a loop an incremental calculation of an estimation of torque actually transmitted at a given moment, while the estimation of the torque really transmitted is insufficient to surpass the estimation of the transmitted torque required to balance the vehicle on the slope;
- after the executing, producing a starting or deactivation command of the automatic parking brake;
- and
- detecting a release demand when the power unit is not engaged,
- wherein the detecting includes, without using any sensor of depression of a clutch pedal of the vehicle, detecting an engaged state by two maps of the estimation of torque transmitted as a function of a degree of depression of an accelerator pedal of the vehicle respectively established when wheels of the vehicle are engaged and when the wheels are disengaged, and comparing the value of the estimation of torque transmitted to each map value addressed by measurement of the degree of depression of the accelerator pedal to produce, if comparison to the first map is positive, a characteristic report of a disengaged state, and if the comparison to the second map is positive, to produce a characteristic report of an engaged state.
A method of assistance in starting a vehicle including a power unit and an automatic parking brake equipped with a mechanism of executing a command to release or deactivate the automatic parking brake, comprising, at least after one starting phase of the power unit:
- estimating a transmitted torque value required to balance the vehicle on a slope;
- executing in a loop an incremental calculation of an estimation of torque actually transmitted at a given moment, while the estimation of the torque really transmitted is insufficient to surpass the estimation of the transmitted torque required to balance the vehicle on the slope;
- after the executing, producing a starting or deactivation command of the automatic parking brake;
- and
- detecting idling speed, including:
- comparing information on estimated engine torque (Cme) to two functions of estimation of the idling speed in rotation with an estimation of positive transmitted torque fp( ) and in rotation with an estimation of negative transmitted torque fn( ),
- applying to the function fp( ) an idle gain applied on the estimated engine torque, an offset on the estimated engine torque value in an idle position, and the estimated engine torque to produce an idling speed value in rotation with an estimation of positive transmitted torque,
- applying to the function fn( ) an idle gain applied on the estimated engine torque, an offset on the estimated engine torque value in an idle position, and the estimated engine torque to produce an idling speed value in rotation with an estimation of negative transmitted torque,
- comparing an engine speed value to determine whether a positive or negative idling speed is present, on rotation with an estimation of positive transmitted torque or with an estimation of negative transmitted torque, and
- authorizing release of the automatic parking brake only if no idling speed is detected.
A method of assistance in starting a vehicle including a power unit and an automatic parking brake equipped with a mechanism of executing a command to release or deactivate the automatic parking brake, comprising, at least after one starting phase of the power unit:
- estimating a transmitted torque value required to balance the vehicle on a slope;
- executing in a loop an incremental calculation of an estimation of torque actually transmitted at a given moment, while the estimation of the torque really transmitted is insufficient to surpass the estimation of the transmitted torque required to balance the vehicle on the slope;
- after the executing, producing a starting or deactivation command of the automatic parking brake;
- and
- producing a horizontal starting operation without a threshold on pressing an accelerator pedal of the vehicle, including:
- producing a parking brake release command on sole determination that the estimation of the torque actually transmitted is higher than a predetermined threshold and without testing the threshold on pressing the accelerator pedal,
- initializing a starting state variable on starting up the vehicle, to indicate that the accelerator pedal has not yet been depressed, to 0,
- reading a rest variable representative of a state of rest of an engine of the vehicle,
- treating a stabilizing state variable so that the variable stays at 1 as soon as the accelerator has been pressed and until an idle variable returns to 1,
- and then authorizing horizontal starting when the starting state variable equals 0 and testing that the estimation of the torque actually transmitted is higher than the predetermined threshold value to authorize release of the automatic parking brake and thus ensure starting of the vehicle keeping the vehicle in a certain range of acceleration.
A method of assistance in starting a vehicle including a power unit and an automatic parking brake equipped with a mechanism of executing a command to release or deactivate the automatic parking brake, comprising, at least after one starting phase of the power unit:
- estimating a transmitted torque value required to balance the vehicle on a slope;
- executing in a loop an incremental calculation of an estimation of torque actually transmitted at a given moment, while the estimation of the torque really transmitted is insufficient to surpass the estimation of the transmitted torque required to balance the vehicle on the slope;
- after the executing, producing a starting or deactivation command of the automatic parking brake;
- and
- determining a term of anticipation on the release command of the automatic parking brake dependent on predetermined anticipation values, which includes, upon elaboration of the automatic parking brake release command, also executing measuring a degree of depression of an accelerator pedal of the vehicle, and then measuring a time derivative of a signal of the degree of depression, and comparing the instantaneous derivative value with a predetermined threshold, so that if the time derivative of the signal of the degree of depression is greater than the predetermined threshold value, the incrementation loop of the estimation of the torque actually transmitted is interrupted before the estimation of the torque actually transmitted is sufficient to surpass the estimation of the torque required to balance the vehicle on the slop, to produce in advance the automatic parking brake release command.
Dependencies are inferred from the claim text.