Natural gas vehicles have power, torque, and fuel consumption that is similar to diesel and gasoline vehicles. There are more than 30,000 natural gas engines used in factory-built vehicles across North America. Power and torque curves for natural gas engines now map closely with the curves for diesel engines of the same ratings.
See for yourself how natural gas holds its own compared to diesel in this heavy truck drag race from the Ports of Los Angeles and Long Beach in California:
Trucks and buses that use the Cummins Westport 8.9 litre and 11.9 litre engines have the advantage of only needing a passive three-way catalyst rather than a diesel particulate filter and a selective catalyst reduction system. This three-way catalyst is similar in size to a truck muffler.
Five power ratings are available for vehicles using the Cummins Westport 8.9 litre natural gas engine.
Six power ratings are available for vehicles using the Cummins Westport 11.9 litre natural gas engine.
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.