Motors Automobiles 904 Maintenance and repair 213 Performance 140 Design and construction 126 Exhaust gas 96 Motor vehicles 91 Cooling systems 90 Modification 81 Computer control systems 78 Fuel injection systems 77 Internal combustion engines 70 Exhaust systems 65 Control systems 60 Fuel systems 53 Radiators 37 Combustion 35 Testing 35 Examinations 34 Electronic equipment 33 Pollution control devices 32 Spark ignition engines 30 Motors (Diesel) 25 Turbochargers 25 Airplanes 24 Engines 22 Measurement 22 Trucks 22 Automatic control 21 Environmental aspects 20