This paper is an attempt to gather major technological advancements regarding CNG utilization for heavy-duty applications emphasizing on four basic configurations; a) mono-fuel (CNG only), b) compression-ignition or diesel environment, c) spark-ignited or gasoline environment, and d) blending with hydrogen. Besides, some elaboration on Liquefied Natural Gas (LNG) and emission reduction strategies (preferably NOx emission reduction) based on emission standards have also been highlighted. It has been widely accepted that direct injection (DI) offers the best solution for dedicated heavy-duty NGV's. To acquire throttleless operation, direct-injection stratified charge (DISC) engines require the ability to run 'lean' (less fuel per volume of air than a conventional engine). When operating in diesel environment, a number of pilot diesel sprays provide multiple ignition sites for the directly injected natural gas while the basis of glow plug ignition is the initiation of combustion by heat transfer from a high temperature surface. A dual-fuel diesel engine with induced natural gas also has its merits to simultaneously eliminate knocking and reduce THC and NOx over a wide IMEP range. DI strategy is also tried in Spark ignited Otto cycle engines, although retrofitting has its own benefits. Yet, a possible approach for meeting future emission regulations with current natural gas engine design is to blend hydrogen with compressed natural gas (CNG). In this context, Hydrogen assisted jet ignition (HAJI) has got potential prospects. For long-range operations of some heavy-duty vehicle applications, LNG seems to be the viable option offering lower emission for PM, non-methane hydrocarbon (NMHC) and NOx emissions. Focusing upon the environmental concerns, different emission reduction legislations (i.e., EPA, EURO) motivate these technological advancements.
Recent CNG developments and its implications for heavy-duty vehicles
Jüngste Entwicklungen im Erdgasbereich und ihre Bedeutung für Schwerlastfahrzeuge
2006
15 Seiten, 4 Bilder, 1 Tabelle, 69 Quellen
Conference paper
English
Propane Fueled Heavy-Duty Vehicles
SAE Technical Papers | 1993
|Propane fueled heavy-duty vehicles
Automotive engineering | 1993
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