Method for operating a hybrid vehicle
A method for operating a hybrid vehicle, particularly one that includes both a primary and an auxiliary power source. According to one exemplary embodiment, the method seeks to decouple or disassociate a driver's engagement of an accelerator pedal with activation of an auxiliary power source, such as an internal combustion engine. This way, if the driver aggressively engages the accelerator pedal while the hybrid vehicle is being propelled by a battery and an electrical motor, the method will delay activation of the internal combustion engine so that the two events do not appear to be linked or connected to one another. Delaying activation of the internal combustion engine while the electric motor is under a heavy stress load may also improve the drive quality of the hybrid vehicle.
1. A method for operating a hybrid vehicle having a primary power source and an auxiliary power source, comprising the steps of:
(a) receiving a propulsion request while the primary power source is activated and the auxiliary power source is not activated, the propulsion request is in response to an aggressive engagement of an accelerator pedal by the driver;
(b) predicting if the auxiliary power source will be activated in response to the propulsion request; and
(c) if step (b) predicts that the auxiliary power source will be activated in response to the propulsion request, then determining if a delay timer has expired and delaying activation of the auxiliary power source until the expiration of the delay timer so that there is a decoupling between the propulsion request that is in response to an aggressive engagement of the accelerator pedal by the driver and activation of the auxiliary power source, wherein delaying activation of the auxiliary power source includes waiting until the delay timer has expired and the driver is no longer aggressively engaging the accelerator pedal before cranking an internal combustion engine.
2. The method of claim 1 , wherein step (a) further comprises receiving a propulsion request from an accelerator pedal sensor, and the propulsion request is representative of a torque being manually requested by the driver.
3. The method of claim 1 , wherein step (a) further comprises receiving a propulsion request from an electronic module in the vehicle, and the propulsion request is representative of a torque being automatically requested by the electronic module.
4. The method of claim 1 , wherein step (b) further comprises predicting if the auxiliary power source will be activated by extracting a requested torque from the propulsion request and comparing the requested torque to a torque threshold.
5. A method for operating a hybrid vehicle having a primary power source and an auxiliary power source, comprising the steps of:
(a) receiving a propulsion request while the primary power source is activated and the auxiliary power source is not activated, the propulsion request is in response to an aggressive engagement of an accelerator pedal by the driver;
(b) predicting if the auxiliary power source will be activated in response to the propulsion request; and
(c) if step (b) predicts that the auxiliary power source will be activated in response to the propulsion request, then determining if a delay timer has expired and delaying activation of the auxiliary power source until the expiration of the delay timer so that there is a decoupling between the propulsion request that is in response to an aggressive engagement of the accelerator pedal by the driver and activation of the auxiliary power source, wherein step (c) further comprises determining a power train load that is representative of a mechanical stress that is in the power train of the hybrid vehicle and is associated with operation of the primary power source.
6. The method of claim 5 , wherein the primary power source is an electric motor used for vehicle propulsion and the power train load is calculated using at least one of the voltage or the current that is provided to the electric motor.
7. The method of claim 5 , wherein step (c) further comprises comparing the power train load to a load threshold, and if the power train load does not exceed the load threshold then continuing to delay activation of the auxiliary power source, and if the power train load does exceed the load threshold then determining at least one battery condition.
8. The method of claim 7 , wherein step (c) further comprises comparing the at least one battery condition to a battery threshold, and if the battery condition exceeds the threshold then continuing to delay activation of the auxiliary power source, and if the battery condition does not exceed the battery threshold then activating the auxiliary power source.
9. The method of claim 8 , wherein the at least one battery condition is a state-of-charge (SOC) and the battery threshold is a lower SOC limit minus a predetermined percentage.
10. The method of claim 1 , wherein the primary power source is an electric motor that is driven by a high-voltage battery and the auxiliary power source is an internal combustion engine that drives an electric generator.
11. A method for operating a hybrid vehicle having a primary power source that includes an electric motor and an auxiliary power source that includes an internal combustion engine, comprising the steps of:
(a) receiving a propulsion request from an accelerator pedal sensor;
(b) using the propulsion request to determine if the internal combustion engine will be turned on; and
(c) if step (b) determines that the internal combustion engine is to be turned on, then lowering a desired state-of-charge (SOC) range for a battery instead of immediately turning on the internal combustion engine so that there is a disconnection between the propulsion request and turning the internal combustion engine on.