The tricycle or three-wheeler is a major mode of community transportation and a source of livelihood for many Filipinos. Tricycles ply the secondary and tertiary roads making them the popular and convenient mode of transport for communities. More than a million households are dependent on tricycles for their livelihood.
When the CLEAN AIR ACT was passed, there was heightened awareness on air pollution. The hydrocarbon emissions from 2-stroke powered tricycles, that is nearly 50 times that of a car, did not go unnoticed. Standards for hydrocarbon emissions were liberally mandated at 10,000 parts per million (ppm) and was later made more stringent at 6,000 ppm. This threatened the livelihood of operators and drivers dependent on 2-stroke engines.
Two stroke engines give off large concentrations of hydrocarbon because of their inherent design. Almost 30% of the gasoline and 2T oil that is injected into the combustion chamber escapes unburned through the exhaust port. This is known as scavenging or short-circuiting.
Technology Options for 2-stroke Powered Tricycles was conceptualized to verify the effectiveness of four technologies that claim to have technological, economic and environmental benefits. The four technologies that were studied were: 1) an alternative fuel, 2) bio 2T oil, 3) air bleed device and 4) direct injection technology.
Each technology option underwent two sets of verification: laboratory test and field test. In the laboratory test, the technology options were subjected to a series of drive cycles while the motorcycle was mounted on a chassis dynamometer. Fuel mileage and tailpipe emissions were then measured. In the field test, fuel mileage, and gasoline and 2T oil consumption were monitored daily. Periodic tailpipe emission testing was conducted every 500 kilometers until the motorcycles reached a total of 3,000 kilometers plying their usual route.
Both laboratory and field tests showed that all four technologies brought about improvement in specific parameters in varying degrees. However, the most promising is direct injection since significant reduction in hydrocarbon and carbon monoxide emissions and increased fuel mileage were observed.