Abstract: A cylinder head includes a lifter guide boss part, a concave relief groove portion and a guide portion. The lifter guide boss part defines a lifter bore arranged to slidably support a valve lifter. The concave relief groove portion has a predetermined width and a predetermined depth formed on the lifter guide boss part in a position corresponding to a rotation direction of a cam to avoid an interference between the cam and the lifter guide boss part. The relief groove portion includes a pair of groove side surfaces and a groove bottom surface with a pair of corner sections being formed between the groove bottom surface and the side groove surfaces. The guide portion protrudes from the groove bottom surface in a sliding direction of the valve lifter to slidably guide the valve lifter. The guide portion is spaced apart from the corner sections of the relief groove portion.

Abstract: There is provided a shift control device for an automated manual transmission having power transmission lines equipped with respective start clutches and gears. The shift control device includes clutch actuation mechanisms and a transmission shift controller that causes the clutch actuation mechanisms to regulate the clutch engagement forces applied to the start clutches so as to perform clutch changeover upon gear selection for a desired gear range in response to a transmission shift command. Each of the clutch actuation mechanisms has primary and secondary clutch engagement force regulation units.

Abstract: A cylinder head includes a lifter guide boss part, a concave relief groove portion and a guide portion. The lifter guide boss part defines a lifter bore arranged to slidably support a valve lifter. The concave relief groove portion has a predetermined width and a predetermined depth formed on the lifter guide boss part in a position corresponding to a rotation direction of a cam to avoid an interference between the cam and the lifter guide boss part. The relief groove portion includes a pair of groove side surfaces and a groove bottom surface with a pair of corner sections being formed between the groove bottom surface and the side groove surfaces. The guide portion protrudes from the groove bottom surface in a sliding direction of the valve lifter to slidably guide the valve lifter. The guide portion is spaced apart from the corner sections of the relief groove portion.

Abstract: A gearwheel unit includes a gear body and a clutch gear. The gear body includes a gear part and a positioning part. The gear part is configured and arranged to transmit rotation of a rotational shaft with a prescribed change gear ratio. The positioning part is integrally formed with the gear part at a position spaced apart from the gear part by a prescribed distance in an axial direction so that a prescribed open space is formed between the positioning part and the gear part. The clutch gear is fixedly coupled to the gear body as being positioned with respect to the gear body by the positioning part so that at least a part of the clutch gear overlaps the prescribed open space formed between the positioning part and the gear part of the gear body when viewed in a radial direction.

Abstract: A rotating member fixing structure includes a shaft member and a rotating member. The rotating member has an axial bore section press-fitted to the shaft member. One of the shaft member and the axial bore section of the rotating member includes a margin adjusting part dimensioned to reduce a press-fitting margin between the shaft member and the axial bore section of the rotating member from an initial press-fitting margin to an effective press-fitting margin that is less than or equal to a prescribed value when the rotating member is press-fitted to the shaft member.

Abstract: A lubricating system is adapted to supply lubricating oil to a lip portion of an oil-seal member for preventing the lubricating oil from leaking out of a case. The lubricating system includes a rotating member, a bearing, a scraping member, and a guiding section. The rotating member is configured and arranged to be rotatably housed within the case and to slidably engage the lip portion of the oil-seal member. The bearing rotatably supports the rotating member. The scraping member is configured and arranged to scrape the lubricating oil discharged from the bearing. The guiding section is configured and arranged to guide the lubricating oil scraped by the scraping member to the lip portion of the oil-seal member.

Abstract: A synchronizing mechanism includes a synchronizer hub, a coupling sleeve, a clutch gear and a synchronizer ling. The synchronizer hub is fixedly coupled to a rotational shaft. The coupling sleeve is coupled to an outer circumference of the synchronizer hub with a spline engagement to slide with respect to the rotational shaft in an axial direction upon an operation of a shift fork. The clutch gear is rotatably supported on the rotational shaft. The synchronizer ring is configured and arranged to produce a synchronized load between the coupling sleeve and the clutch gear. The coupling sleeve includes a guide section configured and arranged to guide at least a portion of lubricating oil supplied from a shift fork engagement part of the coupling sleeve toward at least one of the clutch gear and the synchronizer ring.

Abstract: A cooling system for an internal combustion engine in which bubbles are not transferred to the water pump, and thereby the efficiency of the water pump is maintained. The interior of a water outlet mounted on a cylinder head is divided by a partition wall to form a feeding chamber to feed the coolant introduced from the cylinder head to a first path provided with a radiator, and a receiving chamber forming a second path to receive the coolant returned from a heater core. Between the receiving chamber and the feeding chamber is a channel making one or both chambers communicate with the other. As a result, bubbles in the coolant running through the second path are introduced into the feeding chamber through the channel and removed from the radiator.

Abstract: An oil level adjuster is basically provided with a plug seat, a tubular member and a drain plug. The plug seat has a lower end and an upper end with a drain bore extending between the lower and upper ends for draining oil from an oil pan. The plug seat also has a drainage passageway spaced from the upper end towards the lower end. The tubular member is removably installed in the drain bore and projects beyond the upper end of the plug seat, with the tubular member covering the drainage passageway when fully installed and exposing the drainage passageway to the drain bore when at least partially removed. The drain plug is removably installed in the drain bore of the plug seat to plug the drain bore.

Abstract: A transmission has a rotating shaft, a coupling sleeve fixedly coupled to the rotating shaft to rotate with the rotating shaft and a variable speed gear mounted on the rotating shaft. The variable speed gear is configured to rotate on the rotating shaft when a clutch gear that is embedded in a side surface of the variable speed gear is disengaged from the coupling sleeve and to be fixed to the rotating shaft when the clutch gear is engaged from the coupling sleeve. The coupling sleeve is moved in the axial direction between the engaged and disengaged states by a shifting fork F3. A lubricant supplying structure directs lubricant to the clutch gear by diverting the lubricant against a side surface of the shifting fork that faces the clutch gear and a side surface of the coupling sleeve that faces the clutch gear.

Abstract: An internal combustion engine performing its cooling by means of coolant and being capable of detecting a temperature of the coolant accurately is to be provided. In this engine, there is mounted a water outlet 3 provided with a temperature detecting means 9 for detecting a temperature of the coolant after cooling the engine, and with a rib 7 and an upslope surface 8 both of which are capable of guiding the coolant to a temperature detecting portion 9a of the temperature detecting means 9.

Abstract: An oil pan for internal combustion engine which is lightweight and has improved stiffness and vibration suppression, achieved by reducing the number of components. The oil pan includes an upper portion to be attached to the bottom portion of a cylinder block directly or through an adaptor plate and a lower portion provided on the bottom of the upper portion, with a baffle plate formed integrally downward of the upper portion. An oil supplying means which sucks the oil accumulated in the lower portion and supplies the sucked oil to portions of the internal combustion engine is provided.

Abstract: The oil pan includes an oil introducing portion that has an oil introducing plate. The oil introducing plate has an insertion hole for receiving a sucking portion of an oil strainer. The oil introducing plate extends from the periphery of the insertion hole toward a side wall of the oil pan. The oil returned from the first oil return passage is introduced to flow along the oil introducing plate via an oil falling hole formed in a baffle plate that is positioned at the bottom of a crank case of the internal combustion engine. The oil introducing portion further includes a plurality of inclined wall portions mounted on a bottom portion of the oil pan in the vicinity of the side wall of the oil pan in order to support the oil introducing plate. Opening portions are formed between the inclined wall portions and the bottom portion of the oil pan. The oil introducing plate of the oil introducing portion is located just below the oil falling hole formed in said baffle plate.

Abstract: A partition plate (tumble plate) for an intake port is previously placed in an intake port molding sand core (port core) for forming an intake port of a cylinder head, and cast-in as the cylinder head is cast-molded, to partition the intake port into a plurality of ports. The partition plate is provided with shift preventing portion that prevent positional shift relative to the intake port molding sand core.

Abstract: A cylinder block for an internal combustion engine has a water jacket formed between cylindrically configured cylinder walls and a jacket sidewall. The cylinder walls is arranged to slideably retain pistons therein. The jacket sidewall is disposed around an external periphery of the cylinder walls. A pair of external block walls is provided on transverse sides of the cylinder block to extend almost an entire longitudinal length of the cylinder block. The external block walls are spaced apart from the jacket sidewall in a transverse direction to form gaps therebetween. The top end portions of the external block walls constitute an external flange portion of a top deck of the cylinder block. Thus, the rigidity of the top deck of the cylinder block is improved, and the sealing between the cylinder block and a cylinder head via a head gasket is improved.

Abstract: An apparatus for protecting a fuel system component disposed on an engine body in a vehicle, the apparatus including a protector including a first wall and a second wall connected with the first wall. The first and second walls extend toward the engine body and cooperate with each other to surround the fuel system component. The second wall has one end opposed to the engine body with a clearance. A first fastening member fixes the first wall to the engine body.

Abstract: An engine unit case includes a housing configured to be assembled to a cylinder block of an engine, an oil pump provided at the housing, and a pressure adjusting mechanism for adjusting discharge pressure of the oil pump. The housing is unitarily formed with a pump chamber of the oil pump and a body of the pressure adjusting mechanism.

Abstract: A crankcase emission control device of an internal combustion engine comprises a gas/liquid separator that separates an oil mist from blow-by gases flowing therethrough. A first passage is defined in both a crankcase and a cylinder head to connect an interior of the crankcase to a valve rocker cover chamber defined by the cylinder head. A second passage extends from the valve rocker cover chamber to the gas/liquid separator. A third passage extends from the gas/liquid separator to an intake system of the engine. For reducing the height of the entire construction of the engine, the gas/liquid separator is integrally formed by the cylinder head at a position below intake ports of the cylinder head.

Abstract: An oil pan (6) is mounted to a lower surface of a cylinder block (1) in order to reserve an oil. An oil pump housing (7) is cast integrally with the inner side of the right side surface (6a) of the oil pan (6). A rib (14) is formed in order to connect the right side surface (6a) and a left side surface (6b) of the oil pan (6).

Abstract: A partition plate for an intake port of a cylinder head to be manufactured by cast molding is preliminarily set prior to the cast molding in a sand core applied to form the intake port and then cast in by the cast molding to partition the intake port into a plurality of ports. The partition plate is provided with an intake-side distal end, a cylinder-side distal end, a pair of side edges continuous with the intake-side distal end and the cylinder-sided distal end and to be cast in by molten metal during the cast molding. Each of the pair of side edges having end faces facing in a thickness direction and a side end face continuous with the end faces. The partition plate is further provided with a promoter section provided on at least one of the side end face and the end faces of each of the pair of side edges to promote solidification of the molten metal.