Natural gas vehicles have power, torque, and fuel consumption similar to diesel and gasoline vehicles. Power and torque curves for natural gas engines now map closely with the curves for diesel engines of the same ratings. There are more than 30,000 natural gas engines in use in factory-built trucks and buses across North America.
See for yourself how natural gas holds its own against diesel in this heavy truck drag race from the Ports of Los Angeles and Long Beach in California:
Heavy Truck Drag Race
Trucks and buses that use the Cummins Westport 8.9 litre or 12 litre engine have the advantage of only needing a passive three-way catalyst rather than a diesel particulate filter and a selective catalyst reduction (SCR) system. This three-way catalyst is similar in size to a truck muffler.
The power ratings available for trucks using the Cummins Westport 8.9 litre ISL G natural gas engine are outlined in the following table.
The power ratings available for trucks using the Cummins Westport 11.9 litre ISX G natural gas engine are outlined in the following table.
* Refuse/vocational truck ratings
Performance issues in early generation natural gas engines have been fully resolved with today’s engine technologies. Medium and heavy vehicles that are designed to operate on natural gas do not have any of the power losses associated with early generation aftermarket vehicle conversions.