Method and device for starting an internal combustion engine

Abstract

The invention relates to a method and a device for starting an internal combustion engine (3) of a motor vehicle, said internal combustion engine (3) exerting a drive torque on a crankshaft in a preferred direction of the internal combustion engine (3), a starting motor (9) exerting a starting torque (7) on the crankshaft during a starting process to achieve a minimum rotational speed of the internal combustion engine (3), a control unit regulating the starting torque (7). Said control unit regulates the starting torque (7) in a time-dependent manner between a positive maximum starting torque (27) and a negative minimum starting torque (27) during the starting process, a positive starting torque acting on the crankshaft in the direction of the preferred direction and a negative starting torque in the direction opposite thereto.

Description

technical field

[0001] The invention relates to a method and a device for starting an internal combustion engine. Background technique

[0002] An internal combustion engine is generally not able to start independently, but requires a minimum rotational speed of, for example, 60 to 200 rpm for starting. For this purpose, a battery-powered starter motor is usually used, which can also deliver a breakaway moment when the vehicle is stationary. The basic moments that must be overcome by the breakaway torque during the starting process are breakaway friction moment, friction moment and compression moment. At the beginning of the starting process, the crankshaft of the internal combustion engine is stationary. Static friction occurs via existing friction points such as cylinder running surfaces and / or crankshaft bearings. In order for the crankshaft to rotate completely, this static friction must first be overcome in the first phase. For this, a corresponding torque must be a...

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