Abstract: A dual path exhaust gas recirculation (EGR) system for an engine includes a common EGR intake path and first and second low pressure EGR paths including respective first and second EGR valves. The common EGR intake path is connected to the exhaust system downstream of a catalyst and includes an EGR cooler. The first EGR path is coupled directly to the EGR cooler and an inlet of a turbocompressor. The second EGR path is coupled directly to the EGR cooler and the intake system, thereby bypassing the turbocharger and an engine throttle valve. The engine includes an absence of any high pressure EGR path and the EGR valves are controlled such that the first EGR valve is closed and the second EGR valve is open at low engine speed and load operating conditions thereby providing EGR directly to the intake system that bypasses the turbocharger and throttle valve.

Abstract: A dual path exhaust gas recirculation (EGR) system for an engine includes a common EGR intake path and first and second low pressure EGR paths including respective first and second EGR valves. The common EGR intake path is connected to the exhaust system downstream of a catalyst and includes an EGR cooler. The first EGR path is coupled directly to the EGR cooler and an inlet of a turbocompressor. The second EGR path is coupled directly to the EGR cooler and the intake system, thereby bypassing the turbocharger and an engine throttle valve. The engine includes an absence of any high pressure EGR path and the EGR valves are controlled such that the first EGR valve is closed and the second EGR valve is open at low engine speed and load operating conditions thereby providing EGR directly to the intake system that bypasses the turbocharger and throttle valve.

Abstract: A two stroke engine (10) has an exhaust port (16) extending from a side wall of a cylinder (12). A plate valve (26) is movable to an extended position where is the plate valve blocks the upper edge (54) of the exhaust port 16 to effectively retard the opening of the exhaust valve and retractable to a second position which provides the entire axial extent of the exhaust port (16) to be openable with respect to the cylinder. The position of the plate valve (26) is controlled by a diaphragm bladder (46) which is responsive to pressure in the intake system (19) that is in communication with the bladder (46) via an inlet passage (48).

Abstract: A mechanically driven centrifugal air compressor for an internal combustion engine has an impeller shaft supported in a compressor housing with journal bearings. A helical pinion gear is formed on one end of the impeller shaft and an impeller is attached to the other end. A thrust ring mounted on the impeller shaft near the impeller is sandwiched on one side by a thrust bearing and on an opposite side by the nearest journal bearing and the housing to axially locate the impeller shaft. An internal helical ring gear is rotatably supported on the compressor housing and driven by a pulley that is engaged by a belt that is driven by a pulley of larger diameter fixed to an engine crankshaft. The ring gear meshes with the pinion gear to provide a high overdrive speed ratio in series with the belt and pulley drive from the engine crankshaft which provides a low overdrive speed ratio.

Abstract: A mechanically driven centrifugal air compressor for an internal combustion engine has an impeller shaft supported in a compressor housing with journal bearings. A helical pinion gear is formed on one end of the impeller shaft and an impeller is attached to the other end. A thrust ring mounted on the impeller shaft near the impeller is sandwiched by a thrust bearing and the nearest journal bearing to axially locate the impeller shaft. An integral pulley and internal helical ring gear of molded plastic is rotatably supported on the compressor housing with the pulley engaged by a belt that is driven by a pulley of larger diameter fixed to an engine crankshaft. The ring gear meshes with the pinion gear to provide a high overdrive speed ratio at a low noise level in series with the belt and pulley drive from the engine crankshaft which provides a low overdrive speed ratio.

Abstract: For an internal combustion engine with a high speed air pump, an improved frictional drive including a drum drive member having an internal cylindrical track adapted to engage the shaft of a high speed pump in frictional driving relationship. The drum is rotated by an engine crankshaft through a belt/pulley arrangement including a belt tensioning device which tends to bias the drum against the shaft to generate a strong engagement force between the drum and pump shaft.