摘要: |
We compare the fuel consumption and greenhouse gas emissions of natural gas and diesel heavy-duty (HD) class 8 trucks under consistent simulated drive cycle conditions. Our study included both conventional and hybrid HD trucks operating with either natural gas or diesel engines, and we compare the resulting simulated fuel efficiencies, fuel costs, and payback periods. While trucks powered by natural gas engines have lower fuel economy, their CO2 emissions and costs are lower than comparable diesel trucks. Both diesel and natural gas powered hybrid trucks have significantly improved fuel economy, reasonable cost savings and payback time, and lower CO2 emissions under city driving conditions. However, under freeway-dominant driving conditions, the overall benefits of hybridization are considerably less. Based on payback period alone, non-hybrid natural gas trucks appear to be the most economic option for both urban and freeway driving environments. |