Envirofit - Making the world fit for humanity

Retrofit Technology

In order to validate the viability of a commercial retrofit kit which converts carbureted two-stroke engines to direct in-cylinder fuel injection, it was necessary to test the technology. A field trial of 13 Philippine tricycle taxis was executed between May and December of 2005. The main priorities of the testing were the validation of components and system calibration, characterization of each vehicle's performance with regard to emissions and fuel efficiency, and the development of a repeatable retrofit installation process.

The converted vehicles all contained Kawasaki 125cc (9 KW) carbureted engines, and the motorcycles were fitted with sidecars. Each unit was in active taxi service prior to this field test. Vehicle weight varied between 400-800kg based on side car configuration, and trip length 1-3 km depending on location. The average distance each unit operated was around 5,000 km.

Envirofit's field tests prove that our retrofit kit reduces hydrocarbon emissions by 89%, carbon monoxide emissions by 76%, carbon dioxide emissions by 26%, increases fuel efficiency by 34.8%, and decreases oil usage by 50% (as compared to baselined, carbureted two-stroke engines). Hydrocarbon emissions (at idle) are 90% below DENR's new standards (4500 ppm), while carbon monoxide emissions (at idle) are 97% below DENR's new standards (4.5%). See the environmental impact section for a graph showing these figures.

In January, development of a commercial retrofit kit for a Yamaha RS 100T began. Building off of the experience and design of previous work, the team built the prototype kit and commenced a 5 vehicle field trial in March of 2006. The units average over 1500 kilometers per month, and the drivers are extremely pleased with the fuel / oil savings and general performance of their converted bikes. A slight improvement in fuel and oil efficiency was noted over the Kawasaki kit; some of the current field test results are summarized below.