Abstract: A mounting structure for an air-fuel ratio sensor in a motorcycle is provided which eliminates the influence of water gathered in an exhaust pipe upon the air-fuel ratio sensor and improves the mountability of the air-fuel ratio sensor to the exhaust pipe. The air-fuel ratio sensor is mounted on an exhaust pipe connected to an engine in a motorcycle so that the air-fuel ratio sensor extends radially with respect to a longitudinal axis of the exhaust pipe, and is inclined upward by an angle of 10° or more with respect to a horizontal line H passing through the center of the exhaust pipe 32 in its cross section. The air-fuel ratio sensor is pointed toward the central lateral plane of the motorcycle as viewed in front elevation of the motorcycle.

Abstract: An intake air control device is provided in which a throttle valve is fixed to a valve shaft which is rotatably supported within air intake path of an engine body. An actuator is connected to an end of the valve shaft to reduce the length of a throttle cable while simplifying the structure of a steering handle in the vicinity of the throttle grip. A vehicle body frame includes a head pipe at a front end, and a pair of main frames bifurcated from the head pipe to the left and right and toward the rear. A throttle operating amount detecting module, formed by mounting a throttle operating amount sensor to a storage box for storing a rotating member, which rotates in response to a throttle operation, is supported by one of the main frames in front of an air intake path forming body and arranged between the main frames.

Abstract: An intake air control device is provided in which a valve shaft extends in the left and right direction of a vehicle body frame across an air intake path, and is rotatably supported by an air intake path forming body connected to an engine body, equalizing the distances from a center of the vehicle body frame in the left and right direction to both ends of the intake air control device when arranging the air intake path forming body at the center of the vehicle body frame in the left and right direction. An actuator, which applies a motive power to drive the valve shaft, is connected to one end of the valve shaft, and a throttle operating amount sensor for detecting the throttle operating amount by a vehicle operator is supported by the air intake path forming body and connected to the other end of the valve shaft.

Abstract: An air intake control system is provided for an internal combustion engine of a vehicle. The control system includes an intake port of a cylinder head for an engine main body, a throttle body having a throttle valve and connected to the intake port, an electric actuator having an electric motor and arranged on the throttle body to drive open or close the throttle valve, and a connector disposed on a housing of the electric actuator in a position facing toward one axial end of a crankshaft. The connector is provided in order to connect to an outside conductor to the electric motor of the electric actuator. The resulting configuration facilitates the work to connecting the outside conductor to the connector.

Abstract: A multicylinder internal combustion engine, which can simplify its control and is advantageous against thermal loads or vibrations includes a cylinder head with intake valves and exhaust valves arranged therein. Valve actuators are provided for openably operating the intake valves and exhaust valves, respectively. A cylinder head cover forms, in combination with the cylinder head, a valve actuator chamber with the valve actuators accommodated therein. At least some of the valve actuators are deactivatable to disable their corresponding cylinders. The multicylinder internal combustion engine is a V-shaped internal combustion engine provided with a front bank and rear bank. The cylinders on opposite ends in a direction of a crankshaft are set as full-time operating cylinders.

Abstract: An intake air control device is provided in which a valve shaft extends in the left and right direction of a vehicle body frame across an air intake path, and is rotatably supported by an air intake path forming body connected to an engine body, equalizing the distances from a center of the vehicle body frame in the left and right direction to both ends of the intake air control device when arranging the air intake path forming body at the center of the vehicle body frame in the left and right direction. An actuator, which applies a motive power to drive the valve shaft, is connected to one end of the valve shaft, and a throttle operating amount sensor for detecting the throttle operating amount by a vehicle operator is supported by the air intake path forming body and connected to the other end of the valve shaft.

Abstract: An intake air control device is provided in which a throttle valve is fixed to a valve shaft which is rotatably supported within air intake path of an engine body. An actuator is connected to an end of the valve shaft to reduce the length of a throttle cable while simplifying the structure of a steering handle in the vicinity of the throttle grip. A vehicle body frame includes a head pipe at a front end, and a pair of main frames bifurcated from the head pipe to the left and right and toward the rear. A throttle operating amount detecting module, formed by mounting a throttle operating amount sensor to a storage box for storing a rotating member, which rotates in response to a throttle operation, is supported by one of the main frames in front of an air intake path forming body and arranged between the main frames.

Abstract: An air-fuel ratio setting section sets a target air-fuel ratio KCMD according to the conditions of an engine. An air-fuel ratio correction coefficient calculating section calculates an air-fuel ratio correction coefficient KAF for controlling the air-fuel ratio wherein a detected air-fuel ratio KACT detected by a LAF sensor is converged to the target air-fuel ratio KCMD. A lower limit section constrains the air-fuel ratio correction coefficient KAF so as not to underrun the lower limit value. An upper limit section constrains the air-fuel ratio correction coefficient KAF so as not to exceed the upper limit value. A basic fuel injection time determining section calculates a basic fuel injection time TIM. A fuel injection time calculating section calculates a fuel injection time TOUT based on the target air-fuel ratio KCMD, the air-fuel ratio correction coefficient KAF, the basic fuel injection time TIM or the like, and various engine parameters.

Abstract: A mounting structure is provided for an air-fuel ratio sensor on an exhaust pipe in a motorcycle in which a concentration of oxygen in an exhaust gas can be detected efficiently and accurately by the air-fuel ratio sensor. The air-fuel ratio sensor is mounted on a convergent connector of exhaust pipes, which, in turn, are operatively connected to the cylinders of a multi-cylinder engine. The air-fuel ratio sensor is located upstream of catalytic converters provided in the exhaust pipes, and may be mounted so as to be oriented substantially vertically when the motorcycle is in an upright configuration, or alternatively, may be inclined toward the rear of the motorcycle.

Abstract: A mounting structure for an air-fuel ratio sensor in a motorcycle is provided which eliminates the influence of water gathered in an exhaust pipe upon the air-fuel ratio sensor and improves the mountability of the air-fuel ratio sensor to the exhaust pipe. The air-fuel ratio sensor is mounted on an exhaust pipe connected to an engine in a motorcycle so that the air-fuel ratio sensor extends radially with respect to a longitudinal axis of the exhaust pipe, and is inclined upward by an angle of 10° or more with respect to a horizontal line H passing through the center of the exhaust pipe 32 in its cross section. The air-fuel ratio sensor is pointed toward the central lateral plane of the motorcycle as viewed in front elevation of the motorcycle.