New Tier III diesel from Mitsubishi

This approach stems from the fact that many of the engines are derived from automotive engines that demand this sort of technology.

A new marine diesel introduced by Mitsubishi has reversed this trend with an engine that is fully mechanically controlled yet which is compliant with the EPA Tier III requirements regarding emissions.

This new engine is designed to meet the requirements for heavy duty workboat operations such as tugs, cargo vessels and offshore vessels. Mitsubishi says that the new engine will be particularly suitable for re-powering applications where it can replace a similar heavy duty older engine whilst meeting the latest emission standards.

The new S6R-Y3MPTAW-1 model is a propulsion-certified unit and it offers an output of 684hp (510 kW) at 1,800 rpm. The unusual aspect of this new engine is that it provides a high displacement and high mass solution that achieves Tier III compliance in a fully mechanically controlled package.

Featuring a six-cylinder design, the new S6R-Y3MPTAW-1 engine is a four-cycle, water-cooled diesel engine with direct injection and fitted with an air-cooled turbocharger. Whereas most competitive engines in the 600 to 700hp range feature an 18 to 19 litre displacement, the new S6R series model from Mitsubishi has a 170mm x 180mm engine bore and stroke which combine to give a displacement of 24.5 litres making it up to 29% larger.

Mitsubishi claims that a bigger displacement means the engine doesn’t have to work as hard to produce horsepower, which leads to longer service life. Also, this new engine offers up to 29% more mass (6,239lbs) than competitive units, further promoting longevity by providing more physical engine mass to absorb the combustion energy.

Unique to Mitsubishi engines, the new S6R 1,800 rpm model is able to meet EPA Tier 3 compliance without the use of complex electronic controls. Utilizing smart engineering and simple mechanical governor controls, Mitsubishi claims that the engine is more reliable, more fuel efficient and easier to maintain than electronically controlled alternatives. Further responding to market requests, the new model includes a mechanical boost compensator to reduce black smoke on acceleration.

The new engine is currently in production and available for purchase through the Mitsubishi Turbo-charging and Engineering network of marine equipment distributors and dealers. Last year Mitsubishi Turbocharger and Engine Europe acquired and merged with the Norwegian Gas & Diesel Power company. The latter specialises in the development of marine gas engine engines and it is anticipated that this merger will lead to a new generation of duel fuel engines for the workboat sector based on Mitsubishi units.

By Dag Pike