1. Field of the Invention
The present invention relates in general to a marine engine, and more particularly to a position sensor for a throttle device of a marine engine.
2. Description of Related Art
Several outboard motors recently have become equipped with engine control systems in response to increased concerns regarding hydrocarbon emissions. Such systems closely monitor and control the fuel/air ratio of the fuel charge delivered to each cylinder. Engine control systems can significantly reduce hydrocarbon emissions, while improving fuel economy and performance.
An engine control system often includes a throttle sensor which detects the angular position of the throttle valves. The sensor sends a signal indicative of the throttle valve position to an electronic control unit of the engine control system. The electronic control unit uses this information to determine the intake air flow rate into the cylinders and to adjust the amount of fuel delivered to the cylinder to obtain a desired fuel/air ratio.
In several prior engines, the throttle sensor often lies on a side of the carburetors opposite the side on which the throttle linkage operates. This arrangement of the throttle sensor within the engine have previously increased the size of the engine, and thus the size of the power head. The power head of an outboard motor generally extends above the transom of the watercraft and, consequently, a larger power head produces greater aerodynamic drag on the watercraft as the watercraft speeds over the water. The size and shape of the power head thus directly affect the amount of drag produced. The prior arrangement of the throttle sensor within the engine has negatively increased the drag experienced by the outboard motor.