Internal combustion engine starting method and starter

Abstract

The invention provides a starting method and starting device for internal combustion engine to easily break down the top dead center of initial compression after the release of decompression operation, while avoiding the upsizing of an electric motor for starting. In an internal combustion engine having a decompression mechanism, a decompression cam rotatable, in relation to a camshaft in the angle Ad between a first and second stop positions, has a cam profile such that an exhaust valve is in an opening state at the first stop position and in a closing state at the second stop position. At engine start (position P1), the decompression cam is rotated in reverse to locate at the first stop position by reversely rotating a crankshaft with the electric motor, and after the crankshaft only is further rotated reversely (position P3), the decompression cam is rotated positively, by positively rotating the crankshaft with the motor. During the decompression cam reaches the second stop position, it makes the exhaust valve in the opening state to enlarge a crankshaft runup angle in either one of compression stroke (S8, S12) included in the range of reverse rotation angle Ar or an initial compression stroke, after starting the positive rotation of decompression cam.

Description

technical field [0001] The invention relates to a starting device and a method for starting an internal combustion engine with the starting device. The internal combustion engine has a crankshaft driven by an electric motor when the internal combustion engine is started. The starting device has an electric motor and a decompression mechanism. An internal combustion engine valve opened and closed by a movable valve cam on a camshaft driven to rotate in synchronization with the rotation of the crankshaft opens with a predetermined decompression lift amount to decompress the compression pressure in the compression stroke of the internal combustion engine. Background technique [0002] Internal combustion engines having a crankshaft driven in rotation by a starter motor at start are well known. There is also known an internal combustion engine having a decompression mechanism that opens and closes an internal combustion engine valve that is opened and closed by a movable valve c...

AI Technical Summary

Problems solved by technology

Therefore, in order to reliably cross the above-mentioned first compression dead point, when using the starter motor to start the internal combustion engine, it is necessary to increase the output drive torque, which has the problem of increasing the size of the starter motor.

In addition, in the above-mentioned conventional decompression device, since the decompression action is only performed in the initial compression stroke after starting, it is difficult to greatly increase the run-up angle.

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