Patent ID: 7694764

Claim:
A power output system that provides power to a driveshaft, comprising: an internal combustion engine operable to provide power to the driveshaft; an electric motoring mechanism that performs motoring, in which the internal combustion engine is forcedly rotated; an electric storage device that supplies electric power to the electric motoring mechanism; a first exhaust gas channel that guides exhaust gas from the internal combustion engine directly to an exhaust gas purifying catalyst; a second exhaust gas channel which contains an unburned-component adsorber absorbs an unburned component in the exhaust gas, and which guides the exhaust gas that has passed the unburned-component adsorber to the exhaust gas purifying catalyst; a channel switching mechanism that switches a channel of the exhaust gas from the internal combustion engine between the first exhaust gas channel and the second exhaust gas channel, by using a negative pressure; a pressure accumulator connected to an intake system of the internal combustion engine and that accumulates therein a negative pressure produced through rotation of the internal combustion engine; a negative-pressure introducing/releasing mechanism that selectively permits and inhibits introduction of the negative pressure from the pressure accumulator into the channel switching mechanism; and a controller that controls the electric motoring mechanism and the negative-pressure introducing/releasing mechanism so as to cause the electric motoring mechanism to effect motoring and thereby switch a channel of the exhaust gas from the first exhaust gas channel to the second exhaust gas channel, when the electric storage device is in a condition that permits the motoring by the electric motoring mechanism, prior to start up of the internal combustion engine; and for controlling the electric motoring mechanism and the negative pressure introducing/releasing mechanism so as to switch the channel of the exhaust gas from the first exhaust gas channel to the second exhaust gas channel by using only the negative pressure accumulated in the pressure accumulator, without effecting motoring by the electric motoring mechanism, when the electric storage device is not in the condition that permits the motoring by the electric motoring mechanism, prior to start-up of the internal combustion engine, and a pressure accumulation state of the pressure accumulator satisfies a predetermined condition.