Every Alternative:Cummins Westport ISL G
The 8.9-liter ISL G has met EPA 2010 emissions standards since 2007 using Stoichiometric cooled-Exhaust Gas Recirculation (SEGR) spark-ignited combustion to create a high-performance natural gas engine. Torque at idle and fuel economy are improved versus lean-burn engines by 30% and 5%, respectively.
Cooled EGR, in combination with stoichiometric combustion (the theoretical or ideal combustion process in which fuel and oxygen are completely consumed), creates an oxygen-free exhaust, which allows for the use of Three-Way Catalyst (TWC) aftertreatment. TWCs are effective, simple, passive devices that are packaged as a muffler and are maintenance-free. The ISL G does not require active aftertreatment such as DPFs or SCR.