Natural gas vehicles have power, torque, and fuel consumption characteristics similar to diesel vehicles. Natural gas engines are available from Cummins Westport for factory-built medium and heavy vehicles. These engine technologies are integrated by truck and bus manufacturers and come with full warranty and support. These products are not available as aftermarket options.
Tractors, trucks, and buses that use the Cummins Westport 8.9 litre or 12 litre natural gas engine have the advantage of not needing a diesel particulate filter or a selective catalyst reduction (SCR) system. Instead, these vehicles use a passive three-way catalyst to manage exhaust emissions.
Performance issues in early generation spark-ignited natural gas engines have been fully resolved with current engine technologies. Today’s fourth-generation technology has improved fuel consumption and higher torque at idle. Enhanced reliability is another area of improvement with today’s natural gas engines.
Daily driving range needs can be met using natural gas for fleets that return to the yard at night or for fleets that operate in regional corridors. Standard-size fuel storage tanks are available in different configurations. Fleets can choose from a range of fuel storage options depending on their onboard fuel and driving range requirements.
Lightweight fuel storage cylinders and lightweight modular bracket systems that integrate fuel cylinders on medium and heavy vehicles provide further improvements in natural gas vehicle performance. Today’s lightweight fuel cylinder weighs less than half of what a steel cylinder weighs.
Natural gas refueling stations can match the fueling times of liquid fuels stations. Total refueling time depends on station size, equipment, and whether compressed natural gas (CNG) or liquefied natural gas (LNG) is being dispensed. Fleets that operate return-to-base CNG vehicles also have the option of having a time fill system in their yard that refills all vehicles during a 8 to 12 hour overnight window.