Exhaust Emissions from Diesel, LPG, and Gasoline Low-power Engines

Abstract

In a way similar to the automotive industry, outboard emissions limits are being constantly revised, which strongly effects the development of the new engines and their compliance. During the last ten years, conventional two-stroke outboard engines, which are used for fishing and recreational boats, have thus been replaced by four-stroke engines or direct-injection two-stroke engines. The objective of this article is to compare various outboard engines and the technical solutions developed for the reduction of exhaust emissions, with special emphasis being placed on the low-power gasoline and diesel outboard engine range. A gasoline outboard engine was also transformed to allow the use of liquefied petroleum gas (LPG) and showed that this technique could be an alternative solution for the future emission limit compliance.

Keywords:

• diesel
• direct injection
• exhaust emissions limits
• gasoline
• LPG
• outboard engines