This paper presents an analytical approach of estimating the minimum torque to start an engine at low temperature down to -30 °C. Obviously, the output torque from a starter motor has to overcome the conventional mechanical friction torque from piston, bearings, valvetrain and auxiliaries, and gas torque from the cylinder pressure/vacuum rise due to piston motion. Using the mechanical friction models developed previously by the author, the paper shows that although piston, bearings and valvetrain are still significant mechanical friction sources for a cold engine, the gas torque is actually the biggest contributor to the minimum required turning torque. The analysis also showed that the gas resistance torque was sensitive to the crankshaft position at the start. For example, for a V8 gasoline engine, the gas resistance torque is the highest if the engine starts at the intake valve close (IVC) position.
Cold engine cranking torque requirement analysis
Sae Technical Papers
JSAE/SAE International Fuels & Lubricants Meeting ; 2007
23.07.2007
Aufsatz (Konferenz)
Englisch
Drag , Pistons , Valves , Engine cylinders , Crankshafts , Starters and starting , Bearings , Gases
Cold engine cranking torque requirement analysis
Kraftfahrwesen | 2007
|The Cold Cranking Simulator and British Engine Cranking Studies
SAE Technical Papers | 1972
|Cold Cranking Team: Battery, Cables, Cranking Motor, Engine Oil
SAE Technical Papers | 1964
|Engine cranking torque referenced to an engine stop position
Europäisches Patentamt | 2015
|Compression temperatures in a cold cranking engine
Kraftfahrwesen | 1988
|