Natural gas seems to be an advantageous alternate fuel in the public transportation sector. It is available and environmentally friendly, even if the greenhouse effect of methane is coming into consideration. The operation range of vehicles running on CNG (Compressed Natural Gas) is relatively low due to the large pressure vessels needed, but is acceptable in the case of urban buses with low daily mileages. Today, Diesel buses dominate the market because of their better part-load fuel efficiency due to the Diesel principle. The efficiency levels of spark-ignition (Sl)-type, lean-burn natural gas engines are quite comparable to Diesel engines during full load conditions. The penalty in on-road fuel consumption results from the 60 to 80% share of idle / low load engine operation. To overcome this, throttling in natural gas engines should be reduced or eliminated. In a supercharged lean-burn engine, the load in the upper range can be influenced to a certain extent via waste-gate or VNT control. The low load / idle operation requires a stratified charge, instead of the homogenous charge at high loads, being achieved by a pilot injection-type engine which is equipped with an injection device ingesting small diesel amounts to replace the spark plug: ca. 1 to 3% at full load and 100% at idle conditions. To demonstrate the potential of such operation, FEV set up a demonstration engine with common rail injection system. The 6-cylinder HD engine is supercharged and intercooled. Unlike conventional dual-fuel engines, the emission level in steady-state operation is below EURO V (valid 2008) and, except methane, comparable to SI-engines. On the other hand, unlike conventional SI-engines, the fuel consumption is similar to Diesel engines.
Fuel efficient natural gas engine with common-rail micro-pilot injection
Verbrauchsarmer Erdgasmotor mit Common-Rail Micro-Pilot Einspritzung
2000
8 Seiten, 18 Bilder, 12 Quellen
Aufsatz (Konferenz)
Englisch
Brennstoffeinspritzung , Brennstoffverbrauch , Dieselkraftstoff , Dieselmotor , Drosselsteuerung und -regelung , Einspritzmotor , Einspritzvorrichtung , Erdgas , Euronorm , Flüssigerdgas , Methan , Mikropumpe , Nahverkehr , Schichtaufladung , thermischer Wirkungsgrad , Common-Rail-Einspritzsystem , Dieselgasmotor , CO2-Emission
Fuel Efficient Natural Gas Engine with Common-Rail Micro-Pilot Injection
SAE Technical Papers | 2000
|Fuer efficient natural gas engine with common-rail micro-pilot injection
Kraftfahrwesen | 2000
|2000-01-3080 Fuel Efficient Natural Gas Engine with Common-Rail Micro-Pilot Injection
British Library Conference Proceedings | 2000
|Study on pilot injection of DI diesel engine using common-rail injection system
Online Contents | 2002
|Study on pilot injection of direct injection diesel engine using common-rail injection system
Kraftfahrwesen | 2002
|