Optimized Natural Gas Hybrid-Electric Drayage Truck Demonstration
December 20, 2021
Energy Research and Development (500)
Natural Gas Program
Tyler Manley, Dr. Kent Johnson, Dr. J Wayne Miller
California’s heavy-dutyfleetsthattransportgoods and freight primarily rely on diesel engines becausethey arerobust, durable andhighly efficient.With more stringent engineemissionstandards and the increased availability of low-costnatural gas fuel,there is increased interest intrucks powered by naturalgas engines.Thesenatural gas truckscanreduceoxides of nitrogen(NOx)emissionsby 90 percentandcarbon dioxide emissions by25percentcomparedto equivalentdieseltrucks.Despite these advantages, natural gastruckefficiency and performancemust improve to more effectively compete with incumbent diesel technology.
This projectdesigned,integrated,and demonstrateda prototype hybrid-electric/natural gas drayagetruckto achieve near-zeroNOxemissionsand significant greenhouse gas savings.The engine’s emission control functionsweremodifiedtodrive tolower NOxemissions.
The research team foundthatmore than80percentofNOxemissionsoccurduring the cold startperiod andmajorchanges wererequiredto reachnear-zerolevels.The project team exploredmultiplepathways to modify the engine control system, vehicle components, or the hybrid module.Results showed thehybrid-electrictruck could easily move twice the load of thebaselinenonhybridnatural gastruck with reducedemissions andwith a 5percentincrease in fuel economy. In addition, the range of thehybrid truckwasextended to an estimated 400 miles.