Vehicle control apparatus

A vehicle control apparatus to be applied to a hybrid vehicle, the vehicle control apparatus comprising:

• an electric motor coupled to one or both of a first wheel and a second wheel of the vehicle;
• an engine coupled to one or both of the first wheel and the second wheel via a power transmission path;
• a clutch mechanism provided on the power transmission path;
• a torque converter provided on the power transmission path, wherein the torque converter is disposed between the engine and the clutch mechanism;
• and
• a control system comprising a processor and a memory that are communicably coupled to each other, the control system being configured to control the electric motor, the engine, and the clutch mechanism, wherein
• the control system is configured to:
• switch a traveling mode of the hybrid vehicle between a motor mode, in which the electric motor is driven while the clutch mechanism is disengaged, and an engine mode, in which at least the engine is driven while the clutch mechanism is engaged;
• determine a requested driving force based on an amount of an operation of an accelerator of the hybrid vehicle;
• determine a threshold for comparison with the requested driving force based on a vehicle speed of the vehicle;
• when the traveling mode of the hybrid vehicle is the motor mode and the requested driving force is a first driving force that is equal to or less than the threshold, control the electric motor to output the first driving force;
• in response to an increase in the requested driving force in the motor mode, from the first driving force to a second driving force, determine to switch the traveling mode from the motor mode to the engine mode, the second driving force being greater than the threshold;
• in response to determining to switch the traveling mode from the motor mode to the engine mode, start execution of (i) a first control to cause the electric motor to output a third driving force that is greater than the threshold and smaller than the second driving force, (ii) a second control to start the engine, and (iii) a third control to engage the clutch mechanism that is released;
• after starting execution of the second control, determine whether starting of the engine is completed based on a rotational speed of the engine;
• after starting execution of the third control, determine whether engagement of the clutch mechanism is completed based on a difference between a rotational speed of an input shaft of the clutch mechanism and a rotational speed of an output shaft of the clutch mechanism;
• in response to (i) determining that the starting of the engine is completed and (ii) determining that the engagement of the clutch mechanism is completed, determine whether a delay time has elapsed from a first timing at which (i) the determining that the starting of the engine is completed and (ii) the determining that the engagement of the clutch mechanism is completed are made;
• maintain execution of the first control from starting execution of the first control until a second timing at which determining that the delay time has elapsed from the first timing is made;
• after the second timing, terminate the first control and start execution of a fourth control to control the electric motor and the engine such that a combined driving force that is a sum of a driving force output by the electric motor and a driving force output by the engine increases toward the second driving force at a driving force change rate;
• and
• terminate the fourth control and start execution of a fifth control to control the electric motor and the engine such that the combined driving force follows the requested driving force,
• wherein the control system is configured to determine the delay time such that (i) that the delay time exceeds a predetermined time to allow an increase or decrease in an engine torque to be reflected in a turbine torque of the torque converter, and (ii) that the delay time becomes shorter as the amount of the operation of the accelerator at a third timing becomes greater, the third timing being a timing at which the determining to switch the traveling mode from the motor mode to the engine mode is made, and
• wherein the control system is configured to determine the driving force change rate such that the driving force change rate becomes greater as the amount of the operation of the accelerator at the third timing becomes greater.