C.r.f. Societa Consortile Per Azioni

Tecumseh Products Company

Stefano Albanello

Lorentino Macor

Francesco Vattaneo

Giuseppe Ghelfi

Maurizio Borio

Paolo Mion

Rosario Nasto

Giovanni Arisio

A compression release mechanism for small internal combustion engines, including a compression release member having an auxiliary cam and a weight section. The compression release member is supported for rotation on an annular bearing surface which is in eccentric relation to the longitudinal axis of the engine camshaft. At engine cranking speeds, the compression release member rotates with the camshaft, and the auxiliary cam projects beyond the base circle of a cam lobe on the camshaft to periodically engage a valve to vent pressure from the engine combustion chamber during the compression stroke of the piston to aid in engine cranking. After the engine starts, rapid rotation of the camshaft causes the compression release member to rotate under the inertial load of the weight section thereof to a position in which the auxiliary cam is retracted within the base circle of the cam lobe such that combustion may proceed in a conventional manner.

Compression release mechanism

The present invention provides a lubrication system for small internal combustion engines. In a first aspect, a helical oil pump includes a helical insert which is disposed within a bore in the engine camshaft and is rotationally fixed with respect to the crankcase. During running of the engine, rotation of the camshaft draws oil from the oil sump upwardly through the bore in the camshaft and around the helical insert to provide lubrication oil directly to the upper camshaft bearing and to the upper crankshaft bearing. In another aspect, an impeller oil pump includes a pump chamber defined between the camshaft gear and a pump body which is rotationally fixed with respect to the crankcase and in communication with the oil sump. An impeller assembly mounted on the camshaft is disposed within the pump chamber, and draws oil from the oil sump into the pump chamber. The oil is forced outwardly of the pump chamber through an opening in the camshaft gear in the form of a stream of pressurized oil which is directed toward different locations within the crankcase as the camshaft gear rotates with the camshaft.

Engine lubrication system

In an internal combustion engine having a hydraulic system for valve variable actuation and a hydraulic braking device for slowing down the valve during the final portion of its closing travel, this hydraulic braking device is arranged so as to be substantially insensitive to variations in viscosity of the fluid resulting from variations of the temperature.

Internal combustion engines with variable valve actuation

An internal combustion engine having a hydraulic system for valve variable actuation and a hydraulic braking device for braking the valve in the final stage of its closing travel. A passage is provided for excluding the above mentioned braking when the engine is in operative conditions in which the fluid used in the device has a viscosity greater than a predetermined value.

Internal combustion engine with variable valve actuation

A variable valve actuating system for an internal combustion engine includes an auxiliary pressure accumulator having a one-way type of operation, provided with pawl-like stop means to hold a piston at a position reached due to an increase of pressure within the chamber of the accumulators, against the action of return spring means. When the engine is started, the stop means are deactivated.

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Chatillon, Italy

Stefano Albanello