Evaluation of Fuel Consumption and Dynamic Performance of a Compressed Natural Gas Hybrid Electric Truck

The objective of the project was to compare the fuel consumption of a prototype hybrid electric CNG truck with that of two trucks: a CNG truck and a diesel truck for the similar market and operating conditions. The tests were conducted on a test route representative of the conditions encountered by these vehicles in normal driving operations. The test route length was 276 km with a maximum altitude difference of 374 m. The test route had four sections, including a hilly section with a length of 88 km. The result of the comparison between the two CNG trucks was expressed as fuel savings of CNG in percentage. The fuel consumption of the diesel truck was accurately measured using the gravimetric method. The hybrid electric CNG truck showed average fuel savings of 3.6% and demonstrated up to 7.7% in savings for the entire trip compared to the CNG truck. On the hilly section of the route, the hybrid electric CNG truck showed average fuel savings of 22% for the ascending portion and 9.7% for the complete section. On this section, the hybrid electric CNG truck also demonstrated superior dynamic behavior compared to the other two trucks. The torque and power contribution of the electric axle led to a less demanding and more economical behavior for the hybrid electric truck engine on the ascending section of the hilly route. The hybrid electric truck took a shorter time to complete the hilly section of the route compared to the other two trucks.