Hybrid vehicle and method for controlling hybrid vehicle

A hybrid vehicle, comprising

• an internal combustion engine;
• purifying means including a catalyst that purifies exhaust gas discharged from the internal combustion engine;
• electric power storage means;
• electric power/power reception/output means that is connected to a first axle and an output shaft of the internal combustion engine, and that receives power from the output shaft and outputs the power to the first axle or receives power from the first axle and outputs the power to the output shaft while exchanging electric power with the electric power storage means and exchanging power with the internal combustion engine;
• an electric motor that receives power from the first axle or a second axle that differs from the first axle or outputs power to the first axle or the second axle, and that exchanges electric power with the electric power storage means;
• operation mode setting means for setting an execution operation mode to one of multiple operation modes which define respective different ranges where a required drive power required to cause the vehicle to run can be set, and for allowing, when the execution operation mode is set to a predetermined operation mode that is one of the multiple operation modes, a driver to select any one of operation modes included in the predetermined operation mode;
• target air-fuel ratio setting means for setting a target air-fuel ratio for the internal combustion engine under a first constraint when the driver is not allowed to select any one of the operation modes included in the predetermined operation mode, and for setting the target air-fuel ratio under a second constraint, under which the target air-fuel ratio tends to be set to a value richer than the target air-fuel ratio set under the first constraint, when the driver is allowed to select any one of the operation modes included in the predetermined operation mode;
• required drive power setting means for setting the required drive power according to the execution operation mode set by the operation mode setting means;
• and
• control means for controlling the internal combustion engine, the electric power/power reception/output means, and the electric motor so that an air-fuel ratio in the internal combustion engine becomes equal to the target air-fuel ratio set by the target air-fuel ratio setting means and a drive power corresponding to the required drive power set by the required drive power setting means is output.

A method for controlling a hybrid vehicle including an internal combustion engine;

• a purifying device including a catalyst that purifies exhaust gas discharged from the internal combustion engine;
• an electric power storage device;
• an electric power/power reception/output device that is connected to a first axle and an output shaft of the internal combustion engine, and that receives power from the output shaft and outputs the power to the first axle or receives power from the first axle and outputs the power to the output shaft while exchanging electric power with the electric power storage device and exchanging power with the internal combustion engine;
• an electric motor that receives power from the first axle or a second axle that differs from the first axle or outputs power to the first axle or the second axle, and that exchanges electric power with the electric power storage device;
• and an operation mode setting device that sets an execution operation mode to one of multiple operation modes which define respective different ranges where a required drive power required to cause the vehicle to run can be set, and that allows, when the execution operation mode is set to a predetermined operation mode that is one of the multiple operation modes, a driver to select any one of operation modes included in the predetermined operation mode, comprising:
• setting a target air-fuel ratio for the internal combustion engine under a first constraint when the driver is not allowed to select any one of the operation modes included in the predetermined operation mode;
• setting the target air-fuel ratio under a second constraint, under which the target air-fuel ratio tends to be set to a value richer than the target air-fuel ratio set under the first constraint, when the driver is allowed to select any one of the operation modes included in the predetermined operation mode;
• and
• controlling the internal combustion engine, the electric power/power reception/output device, and the electric motor so that an air-fuel ratio in the internal combustion engine becomes equal to the set target air-fuel ratio and a drive power corresponding to the set required drive power is output.