Fuel efficiency benefits of electrified CNG vehicles

According to Natural Gas Vehicles for America, more than 120,000 vehicles in the United States now run on compressed natural gas (CNG). Around the world, however, there are now more than 8.7 million natural gas vehicles (NGVs) - so the United States has only 1.4% of all CNG vehicles. In addition, vehicle electrification is seen as an effective way to improve vehicle fuel efficiency. This study evaluates the benefits of CNG as compared to gasoline based on state-of-the-art technologies for a wide variety of powertrain configurations, including conventional; start-stop sys t e m s; mild hybrids; pre-transmission full hybrid electric vehicles (HEVs); single-mode power-split vehicles; single-mode power-split 10-mi all-electric range (AER) vehicles; and General Motors´ Voltec (an extended-range electric vehicle [E-REV]) with a 40-mi AER. State-of-the-art engine maps for both gasoline and CNG generated from the same engine were used for the simulation. First, the impact of switching from gasoline to CNG without any engine resizing is analysed. Next, all of the CNG vehicles, which were sized to meet the same Vehicle Technical Specifications (i.e., performance, grade) as the gasoline vehicles, are compared. The impacts on fuel efficiency of the different fuels are then compared.