A Preliminary Study of LPG as an Alternative Fuel for Philippine Jeepneys

This paper presents a preliminary study to estimate, using on-road and laboratory tests, the mileage range of liquefied petroleum gas (LPG) as an alternative fuel for diesel-fed public utility jeepneys in the Philippines. Data from the study would be used by the Philippine Department of Energy to formulate and implement alternative fuel programs for public transport. On-road fuel consumption, load factor, and GPS speed data from selected in-use LPG and diesel jeepneys plying a chosen urban route were gathered to develop corresponding drive cycles for chassis dynamometer testing at 100% load factor were conducted to estimate an upper limit for fuel consumption. Measured on-road diesel jeepney mileage was about 6.7 km/liter at 63.5% load factor while that for LPG jeepney was 3.8-4.2 km/liter at 59.8% load factor. Drive cycle tests yielded 5.2 km/liter for diesel and 2.6-3.1 km/liter for LPG. Constant-speed (20-40-60 km/hr) tests at 100% load factor gave a range of 11.5-8.1 km/liter for diesel and 3.0-1.8 km/liter for LPG. The lower LPG jeepney mileage is attributed to LPG’s lesser heating value per liter than diesel, possible non-optimal vehicle and powertrain configuration and tuning, and differences in drive cycles. The authors believe that the approach used in the present study can be adopted for future studies with similar objectives and resource constraints in other Philippine locations.