Fuel systems Diesel motor 94 Automobiles 90 Motors 53 Internal combustion engines 43 Combustion 29 Pollution control devices 26 Motor vehicles 24 Fuel injection systems 19 Maintenance and repair 15 Fuel cells 13 Motors (Diesel) 13 Testing 13 Design and construction 12 Performance 12 Computer control systems 11 Trucks 11 Biodiesel fuels 9 Data processing 8 Fluid dynamics 8 Fuel consumption 8 Alternative fuels 7 Hydrogen as fuel 7 Exhaust gas 6 Motor fuels 6 Airplanes 4 Defects 4 Environmental aspects 4 Fuel switching 4 Hybrid electric vehicles 4