Abstract: A method for controlling a hybrid vehicle including a battery charged with electric power generated by an engine, including a motor as a drive source, and having multiple running modes that can be selected through a mode operation, the running modes including a normal mode configured to perform charging of the battery according to a running state, and a charge mode configured to perform electric power generation by the engine according to a mode operation, the method comprising: setting a range of charge amount that allows for charging of the battery based on the electric power generated; and setting an upper limit of the range of charge amount in the charge mode to be lower than an upper limit of the range of charge amount in the normal mode.

Abstract: A catalyst warm-up control method for a hybrid vehicle supplies electric power to an electric motor by a battery, to charge the battery by a power generation engine, and to treat exhaust gas from the engine with a catalyst, the hybrid vehicle selecting a manner mode in which power generation using the engine is stopped. The catalyst warm-up control method performs catalyst warm-up control such that when the temperature of the catalyst becomes lower than a normal threshold temperature for activating the catalyst, the target rotation speed of the engine is controlled to a first warm-up required rotation speed at which the catalyst can be heated to a temperature that is higher than the normal threshold temperature. When the manner mode is selected, control is performed when temperature of the catalyst becomes lower than a manner mode threshold temperature that is equal to or less than the normal threshold temperature.

Abstract: A catalyst warm-up control method for a hybrid vehicle includes a battery supplying electric power to an electric motor, the battery is charged by an engine for electric power generation, and exhaust gas discharged from the engine 1 is treated by a catalyst. By the catalyst warm-up control method, when temperature of the catalyst is lower than required warm-up temperature for activating the catalyst, target revolution speed and target torque of the engine are controlled based on a state of charge of the battery, and, when target revolution speed is lower than lower-limit revolution speed at which the catalyst can be heated to the required warm-up temperature, the target revolution speed is controlled so as to be required warm-up revolution speed that is equal to or higher than the lower-limit revolution speed.

Abstract: A control method for a hybrid vehicle including a generator and an electric motor, the generator being configured to charge a battery by use of power of an engine, the electric motor being configured to drive driving wheels by electric power of the battery, is provided, is provided. The control method having controlling the generator and the electric motor and accepting mode setting to set any of a normal mode, a regeneration driving mode, and a silent mode, the regeneration driving mode being a mode in which a regenerative braking force caused by the electric motor is larger than that in the normal mode, the silent mode being a mode in which charging by the engine is inhibited, wherein: when the normal mode is set, setting of the silent mode is not accepted; and when the regeneration driving mode is set, setting of the silent mode is accepted.

Abstract: Method of controlling cooling water temperature of an engine in which the lower limit value of engine rotation speed is set according to outside air temperature and vehicle speed. When the vehicle starts traveling, a temperature raising-state lower limit rotation speed is set to raise the cooling water temperature to a third threshold value. After the cooling water temperature is raised to the third threshold value, the lower limit value is not set. If the cooling water temperature drops to a second threshold value, a maintaining-state lower limit rotation speed lower than the temperature raising-state lower limit rotation speed is set to raise the cooling water temperature. If the cooling water temperature does not rise but drops to a first threshold value, a temperature re-raising-state lower limit rotation speed lower than the temperature raising-state lower limit rotation speed and higher than the maintaining-state lower limit rotation speed is set.

Abstract: Provided is a device for performing degradation diagnosis of a downstream-side exhaust gas sensor. When a diagnosis condition is met, an intake-air quantity is successively accumulated to obtain an intake-air-quantity accumulation value, an intake-air-quantity average value is obtained as an average of the intake-air quantity from the start of diagnosis, and, on the basis of this intake-air-quantity average value, an intake-air-quantity accumulation threshold value is set. When the intake-air-quantity accumulation value reaches the intake-air-quantity accumulation threshold value, the diagnosis is terminated, and an output reversal number of the downstream-side exhaust gas sensor during the diagnosis period is compared with a threshold value to judge whether the sensor is normal or degraded.

Abstract: Provided is a device for performing degradation diagnosis of a downstream-side exhaust gas sensor. When a diagnosis condition is met, an intake-air quantity is successively accumulated to obtain an intake-air-quantity accumulation value, an intake-air-quantity average value is obtained as an average of the intake-air quantity from the start of diagnosis, and, on the basis of this intake-air-quantity average value, an intake-air-quantity accumulation threshold value is set. When the intake-air-quantity accumulation value reaches the intake-air-quantity accumulation threshold value, the diagnosis is terminated, and an output reversal number of the downstream-side exhaust gas sensor during the diagnosis period is compared with a threshold value to judge whether the sensor is normal or degraded.