Abstract: An apparatus and method for cooling a work machine is disclosed. The apparatus has a fan element located inside an engine compartment of the work machine in a horizontal orientation. The fan element draws external air from above the work machine into the engine compartment. A deflector directs the air through a plurality of cooling cores which are radially spaced about the engine compartment and interspersed with a plurality of core spaces. The apparatus can be cleaned by spraying fluid from the outside through the plurality of cooling cores, causing any trapped debris to fall to the bottom of the engine compartment, where it can be removed through a cleanout.

Abstract: A hand-held working tool has a housing and an internal combustion engine arranged in the housing and comprising a crankshaft and an air filter. A tool is driven by the crankshaft of the internal combustion engine. A fan housing is attached to the engine housing and has an air inlet. A fan wheel is arranged in the fan housing and is driven by the crankshaft of the internal combustion engine to supply cooling air, sucked in through the air inlet, to the internal combustion engine. The fan housing has a bottom extending radially to the crankshaft. The bottom and a side of the fan wheel facing the bottom define a chamber in the fan housing. The bottom has a combustion air outlet. A combustion air channel is connected to the combustion air outlet and to the air filter. The combustion air outlet is axially supplying combustion air from the chamber through the combustion air channel into the air filter of internal combustion engine.

Abstract: A manually guided implement having an air-cooled internal combustion engine for driving a tool is provided. Disposed between an output shaft of the internal combustion engine and the tool is a centrifugal clutch, whereby a flywheel portion of the clutch and a fan wheel are fixedly disposed on the output shaft. The flywheel portion is secured on a suction side of the fan wheel that is provided with guide vanes.

Abstract: In a handheld type four-cycle engine, a valve operation mechanism includes a camshaft rotatably supported in a cylinder head so as to open and close an intake valve and an exhaust valve and a timing transmission placed on one side outside an engine main body and providing association between a crankshaft and the camshaft, and a centrifugal clutch for power output is mounted on the crankshaft on the opposite side outside the engine main body. The timing transmission and the centrifugal clutch being positioned at the two ends of the crankshaft improves the weight balance, the center of gravity of the engine can be made as close to the central part of the crankshaft as possible, which, together with the reduced weight, can enhance the operability of the engine.

Abstract: A coolant overflow bottle is interposed between the centrifugal fan and the radiator for guiding air expelled by the fan toward the radiator. The bottle includes a top, a bottom, a pair of nested curved sidewalls, and a rear wall. The side walls are joined at a leading edge, and join the top and bottom. The rear wall is joined to the side walls at a trailing edge, and joins the top and bottom. The bottle wails define an exterior shape for guiding air.

Abstract: A first and second baffle formed of a thin sheet metal material are introduced into an engine induction system on the upstream side of air fuel metering device and interposed between the air fuel metering device and a tubular intake runner in order to prevent post engine shut down fuel boiling. The first and second baffles absorb heat from the induction system and dissipate heat to the surrounding atmosphere. The first and second baffles are sized sufficiently large to limit peak fuel temperature in the fuel metering device 130° F. when a hot engine is shut down in a 70° F. environment.

Abstract: To reduce noise caused by exhausted cooling air as well as to maintain a necessary amount of cooling air of a cooling fan. A cooling fan is positioned behind a radiator. A shroud surrounds an impeller coupled to a motor and a rotating shaft. The shroud has an inlet and an outlet in the shape of a bell mouth. The bell mouth shaped inlet has its front edge spaced from the rear surface of the radiator by a clearance D, and forms a space around its front peripheral edge. A space is formed via the space, and opens around the periphery of the shroud. The ratio A:B is 1:3 to 5, preferably approximately 1:4, where A denotes a difference between maximum and minimum diameters of the bell mouth shaped outlet of the shroud, and B notes a length of the shroud.

Abstract: To reduce noise caused by exhausted cooling air as well as to maintain a necessary amount of cooling air of a cooling fan. A cooling fan is positioned behind a radiator. A shroud surrounds an impeller coupled to a motor and a rotating shaft. The shroud has an inlet and an outlet in the shape of a bell mouth. The bell mouth shaped inlet has its front edge spaced from the rear surface of the radiator by a clearance D, and forms a space around its front peripheral edge. A space is formed via the space, and opens around the periphery of the shroud. The ratio A:B is 1:3 to 5, preferably approximately 1:4, where A denotes a difference between maximum and minimum diameters of the bell mouth shaped outlet of the shroud, and B notes a length of the shroud.

Abstract: The invention relates to a drive unit of a portable handheld work apparatus such a motor-driven chain saw having an internal combustion engine. The crankshaft of the engine drives a tool of the work apparatus and a fan wheel. The fan wheel is held within a fan housing on a drive pin of the crankshaft. A crankcase is rigidly connected to a cylinder of the engine and is made of a metal material. The crankcase is configured of two parts and the axis of the crankshaft lies in the partition plane of the crankcase housing parts which can be connected to each other. A metallic chassis of the drive unit includes a crankcase sump as one of the crankcase halves and has a flange surface lying essentially perpendicularly to the crankshaft axis. The flange surface is at least defined in sections by the free-lying end of the crankcase sump. In this way, the weight and the manufacturing costs of the work apparatus are reduced.

Abstract: The invention is directed to a hub unit of a fan wheel for an internal combustion engine having a crankshaft and a starter device. The hub unit has a wheel body made of plastic and a hub sleeve made of a high tensile strength material. The hub sleeve carries the wheel body and is held on the crankshaft to prevent rotation relative thereto and a clamping element axially fixes the hub sleeve on the crankshaft. A starter ring is concentric with the axis and is adapted for a clutch engagement with the starter device so as to be entrainable thereby. The starter ring and the hub sleeve are originally formed as a single piece to define a hub housing.