Patent ID: 6558214
Filing Date: 2003-05-06
Classification: B63B,B63H,F01L,F01N,F02B

Abstract:
A small planing watercraft having a piston-type internal combustion engine, said engine comprising a high speed-high output engine normally developing maximum power output at a relatively high RPM, said engine including an air intake opening and a rotatable intake valve camshaft actuating at least one intake valve of the engine, wherein said camshaft is driven in synchronous rotation by a camshaft driving device drivingly connected to a crankshaft of the engine and coupled to one end of the camshaft and further wherein said intake valve has normal opening and closing time intervals relative to engine piston and crankshaft positions, said normal opening and closing time intervals arranged to effect said high RPM-high output operating characteristics of said engine, the improvement comprising:a variable intake valve timing device connecting the camshaft driving device to the camshaft and including an intake valve timing control device located adjacent to one end of the engine longitudinally spaced from said intake opening wherein intake air is caused to flow over the valve timing device en route to the engine air intake opening during engine operation; said intake valve timing control device arranged so that during engine operation below a predetermined engine speed at which the engine develops less than maximum power output, the relative driving position of the camshaft driving device and the camshaft is selectively adjusted to advance the timing of the intake valve opening and closing relative to the camshaft driving device, and the relative driving position of the camshaft driving device and the camshaft is adjusted to restore the normal driving relationship between the camshaft driving device and the camshaft when the engine is operated at speeds above said predetermined speed; whereby said engine may produce higher power output at operating speeds below said predetermined speed as compared with engine operating characteristics without advancement of intake valve opening and closing; and an outside air intake duct having an exit opening spaced away from said intake valve control device on a side thereof opposite the side toward which the engine intake opening is located, whereby intake air is caused to flow over the intake valve control device enroute to the engine air intake opening during engine operation.