Yamaha Hatsudoki Kabushiki Kaisha

Denso Corporation

Hisatoshi Kinoshita

Kazuteru Iwamoto

Tatsuya Kasahara

Atsuya Hidai

Atsushi Hirano

Yoshihiko Nonogaki

Minoru Hotta

Nobuyuki Kawashima

Naoki Tsuchida

Yuta Shimizu

Ryota Nakashima

Yoshihiko Moriya

Masaki Torigoshi

Yo Aramaki

Tatsuya Aoyama

Ryo Tomii

Yoh Aramaki

Satoshi Shiokawa

Haruhiko Fujita

An engine unit, including: a plurality of cylinders respectively cooperating with a plurality of pistons; a plurality of individual exhaust pipes configured to allow exhaust gases from the plurality of cylinders to respectively flow therethrough; an exhaust manifold, including a merge portion into which the individual exhaust pipes merge, and a catalyst disposed downstream thereof; a group of pre-catalyst oxygen sensors disposed between the cylinders and the catalyst for all paths of the exhaust gases flowing into the catalyst from the plurality of cylinders; a post-catalyst oxygen sensor disposed in the exhaust manifold, downstream of the catalyst in the flow direction of the exhaust gas; and a control device configured to detect a cylinder-to-cylinder imbalance in air-fuel ratio between the plurality of cylinders, and a deterioration of the catalyst, using detection results of pre-catalyst and post-catalyst oxygen sensors without using an air-fuel ratio sensor.

Individual throttle-type or unequal interval combustion-type multi-cylinder engine unit

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 straddled vehicle on which a part used for performing an inspection for a leak of gas from an evaporative emission system is mounted such that a weight balance of the straddled vehicle is maintained and mass concentrates includes a canister-integrated-leak-detection device that detects a leak of gas from an evaporative emission system. The canister-integrated-leak-detection device configured in a state where at least one of a vent valve or a suction pump is integrated with a canister is supported via a common attaching member to intersect with at least one of a virtual-left-right-center plane that includes a center in a left-right direction and is perpendicular to the left-right direction, a virtual-front-rear-center plane that includes a center in a front-rear direction and is perpendicular to the front-rear direction, or a virtual-up-down-center plane that includes a center in an up-down direction and is perpendicular to the up-down direction in the vehicle.

A drive train abnormality determination device for a straddled vehicle that includes a drive train having a rotator. The drive train abnormality determination device includes an angle signal output unit that periodically outputs an angle signal in accordance with rotation of the rotator, a rotator rotation speed fluctuation physical quantity acquisition unit that acquires a quantity related to a fluctuation in a rotation speed of the rotator, based on the angle signal from the angle signal output unit, a rough road determination unit that determines whether a distribution state or pattern satisfies a predetermined rough road condition, a continuity determination unit that determines whether the rough road condition is continuously satisfied, and a drive train abnormality determination unit that determines, responsive to a determination by the continuity determination unit that the rough road condition is continuously satisfied, that the drive train has an abnormality in its functioning.

Drive train abnormality determination device for straddled vehicle, and straddled vehicle

A vehicle includes at least one of an electric vent valve configured to open and close an outside-air-introduction passage of a canister or an electric suction pump configured to suck gas in a gas passage through which the gas flows. The canister and at least one of the vent valve or the suction pump are disposed such that at least one of a virtual-left-right-center plane that includes a center in a left-right direction and is perpendicular to the left-right direction, a virtual-front-rear-center plane that includes a center in a front-rear direction and is perpendicular to the front-rear direction, or a virtual-up-down-center plane that includes a center in an up-down direction and is perpendicular to the up-down direction is located between a gravity center of the canister and at least one of a gravity center of the vent valve or a gravity center of the suction pump.

A vehicle includes a frame, a seat, a storage box, an engine body at least partially overlapping with the seat when seen from above, an intake system component, a fuel system component, an evaporative emission system, a pressure sensor, and at least one of an electric vent valve or an electric suction pump. At least one of the pressure sensor, the vent valve, or the suction pump is supported by at least one of a frame, a storage box, an engine body, an intake system component, or a fuel system component.

A gas-leak-detection device for detecting a gas leakage from an evaporative emission system includes an electric-wire-connection portion and a passage connection portion that are disposed to overlap with at least one of appearance components in a vehicle when the vehicle is seen in a viewing direction, and are disposed closer to the at least one appearance component than a center plane perpendicular to the viewing direction when the vehicle is in an upright state, the center plane being one of an imaginary-lateral-center plane that is an imaginary vertical plane perpendicular to the left-right direction, an imaginary-longitudinal-center plane that is an imaginary vertical plane including a center in the front-rear direction and being perpendicular to the front-rear direction, or an imaginary-vertical-center plane that is an imaginary horizontal plane including a center in the top-bottom direction and being perpendicular to the top-bottom direction.

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit and a misfire determination unit. The misfire determination unit includes first to third determination units. The first determination unit determines whether or not the crankshaft rotation speed fluctuation physical quantity acquired by the crankshaft rotation speed fluctuation physical quantity acquisition unit is greater than a set physical quantity determination reference. The second determination unit determines whether or not a fluctuation pattern constituted by a physical quantity and the crankshaft rotation speed fluctuation physical quantity acquired at least before or after the physical quantity falls within a set misfire pattern range. The third determination unit determines whether a misfire determination is to be set as effective or not, based on results of determination by the first and second determination units.

Straddled vehicle engine unit and straddled vehicle

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The internal combustion engine has a crankshaft, and a crank angle signal output unit that periodically outputs a crank angle signal in accordance with rotation of the crankshaft. The internal combustion engine is configured to repeat at least two kinds of strokes on a cycle of every 720-degree rotation of the crankshaft. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit configured to acquire a physical quantity related to an amount of fluctuation in a rotation speed of the crankshaft in one kind of stroke, out of the at least two kinds of strokes, based on the crank angle signal from the crank angle signal output unit, and a misfire determination unit configured to perform a misfire determination in response to each acquisition of the crankshaft rotation speed fluctuation physical quantity.

An unequal-interval combustion engine misfire-determination device determines whether a misfire has occurred in an unequal-interval combustion engine including a plurality of cylinders in which combustion occurs at unequal intervals. The misfire determination device includes: an unequal interval combustion fluctuation canceled value acquisition unit that acquires, based on a crank angle signal, an unequal interval combustion fluctuation canceled value which is a rotation speed in a section of 720&#xd7;m crank angle degrees including a predetermined determination angle position, where m is a natural number; an unequal interval combustion fluctuation manifested value calculation unit that calculates an unequal interval combustion fluctuation manifested value in which a fluctuation component attributable to unequal interval combustion is manifested, by removing the unequal interval combustion fluctuation canceled value; and a specific cylinder misfire determination unit that determines a misfire in a specific cylinder based on the unequal interval combustion fluctuation manifested value.

Unequal interval combustion engine misfire determination device and vehicle

A misfire determination device includes: a combustion fluctuation canceled value acquisition unit that acquires a first combustion fluctuation canceled value corresponding to a first angle position and a second combustion fluctuation canceled value corresponding to a second angle position; a combustion fluctuation manifested value calculation unit that calculates a first fluctuation manifested value by removing the first combustion fluctuation canceled value from a rotation speed at the first angle position, and calculates a second fluctuation manifested value by removing the second combustion fluctuation canceled value from a rotation speed at the second angle position; a first-order difference calculation unit that calculates a first-order difference between the first fluctuation manifested value and the second fluctuation manifested value; and a specific cylinder misfire determination unit that determines a misfire in a specific cylinder by using the first-order difference.

Engine misfire determination device and vehicle

A number of embodiments of valve actuating mechanisms for four-cycle engines including a camshaft and a rocker arm actuated by the camshaft for operating an associated poppet valve. The camshaft and rocker arm followers are configured so as to provide an increasing lever ratio on valve opening for effective rapid valve opening and a decreased lever ratio on valve closing so as to avoid valve bounce. Various arrangements of camshafts and rocker arm positions are disclosed.

Growing community of inventors

Shizuoka, Japan

Hisatoshi Kinoshita