DETERMINATION OF OPERATING RANGES OF MARINE ENGINES

This paper summarizes work performed to define the range of recreational boat engine operation for the National Marine Manufacturers Association (NMMA). Sixteen boats were tested on-water with data acquisition systems to measure engine parameters. Boat types included sterndrive and inboard (SD/I), outboard (OB), and personal watercraft (PWC). Each boat was tested with low loads and at its rated load carrying capacity. Each boat was run at prescribed engine speeds from low to maximum speed during data collection. Maps of each boat's engine operation were produced in order to identify the lowest and highest engine load at each engine speed, based on intake manifold depression (for SD/I and OB) or throttle position (for PWC). Each engine type was then installed in a test cell where the lowest and highest engine loads from on-water testing were duplicated in order to measure the engine's output. The engine's low- and high-load torque was corrected to standard conditions and then normalized in order to compare its operation to the United States Environmental Protection Agency and the California Air Resources Board's emission test cycle.