A new series of diesel outboard motors has been developed and settled on the market since 1987 in Japan and since 1988 outside Japan. The diesel engines for these units were specially developed for outboard use and incorporate several innovative design features and new concepts. They achieve 4500 rpm operation for the first time ever with this kind of small directs injection diesel, and are also the lightest diesel in this horsepower range with a weight power ratio of 1.55 kg/HP. In theearly stage of the development, basic research was conducted on the engine structure and injection/combustion system in order to overcome the weight barrier of the diesel and even so to maintain its durability and reliability for marine use. The result is a unique structure, incorporating an integrated aluminium cylinder headblock with cast ironcyclinder liners casted in, a high speed direct injection combustion system using a mini unit injector, a timing belt drive OHC, direct sea water cooling, a vertical crankshaft, etc. The YDOM (Yanmar Diesel Outboard Motor) features: Certain starting and reliable operation. Extremely low fuel consumption, (1/2 - 1/4 of gasoline consumption) Higher torque and safer cruising. Same maneuverability as GOM (gasoline outboard motor). Low vibration and noise. Less inflammable fuel. With these features, around 3000 units have already been marketed and are performing well, not only on work and fishing boats but on pleasure boats as well.
The development of outboard motors, powered by new concept high-speed diesel engines
Entwicklung von Außenbordantriebseinheiten mit schnellaufenden Dieselmotoren nach einen neuen Konzept
SAE-Papers ; Sep ; 1-8
1989
8 Seiten, 20 Bilder
Conference paper
English
The development of outboard motors, powered by new concept high-speed diesel engines
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