Yamaha Hatsudoki Kabushiki Kaisha

Ryo Tomii

Yuta Shimizu

Hisatoshi Kinoshita

Ryota Nakashima

Nobuyuki Kawashima

Takuma Ito

Tatsuya Aoyama

Makoto Wakimura

Yoh Aramaki

Satoshi Shiokawa

Haruhiko Fujita

A straddled vehicle, including: an engine, which includes a combustion chamber; a three-way catalyst, which is configured to purify exhaust gas exhausted from the combustion chamber; an upstream oxygen sensor, which is provided upstream of the three-way catalyst in a flow direction of the exhaust gas, and is configured to detect an oxygen concentration in the exhaust gas; a downstream oxygen sensor, which is provided downstream of the three-way catalyst in the flow direction of the exhaust gas, and is configured to detect the oxygen concentration in the exhaust gas; and a controller, which includes a processor, and a non-transitory storage medium containing program instructions, execution of which by the processor causes the controller to execute a detachment determination process of determining whether the three-way catalyst is detached at least based on a signal input as a signal of the downstream oxygen sensor.

Straddled vehicle

A catalyst deterioration determining device for use in a straddled vehicle having an engine, a transmission that transmits motive power of an engine, and a catalyst that cleans an exhaust gas from the engine. The catalyst deterioration determining device includes a running state acquirer that acquires a plurality of running states, a state determiner that stores a plurality of allowable conditions, each of which is a condition for determining work in regard to a degradation state of the catalyst to be executed and is based on a relationship among a plurality of gear ratios of the transmission, an intake state of the engine and a rotation speed of the engine, and determines whether the plurality of running states acquired by the running state acquirer satisfy the plurality of allowable conditions, and a determination executor that executes the determining work based on a result of the determination by the state determiner.

Catalyst degradation determining device for straddled vehicle and straddled vehicle including same

A catalyst degradation determining device for a straddled vehicle that includes an engine, a catalyst for cleaning an exhaust gas from the engine, and a throttle valve that is controllable by cruise control of the straddled vehicle to keep a traveling speed of the straddled vehicle constant. The catalyst degradation determining device includes a determiner that determines whether the cruise control is being executed, and an execution controller. The execution controller is configured to determine a degradation state of the catalyst while controlling an air-fuel mixture supplied through the throttle valve to the engine, in a case where the determiner determines that the cruise control is not being executed, and at least one running state of the straddled vehicle satisfies at least one predetermined allowable condition, and not to determine the degradation state of the catalyst in a case where the determiner determines that the cruise control is being executed.

Growing community of inventors

Shizuoka, Japan

Ryo Tomii