STARTING METHOD FOR INTERNAL COMBUSTION ENGINE AND STARTING DEVICE FOR THE SAME

摘要

To facilitate the piston to get over the first compression top dead center after stoppage of decompression operation without upsizing an electric motor for actuation. In an internal combustion engine provided with a decompression mechanism, a decompression cam that is rotatable with respect to a camshaft within the angle Ad between the first and second stop positions has such a cam profile that an exhaust valve is opened at the first stop position and is closed at the second stop position. The decompression cam is rotated in the reverse direction to the first stop position by rotating the crankshaft in the reverse direction by the electric motor at startup (position P1), and then only the crankshaft is rotated in the reverse direction (position p3), and then the decompression cam is rotated in the normal direction by rotating the crankshaft in the normal direction by the electric motor. During either the compression strokesS8 included within the range of the reverse rotation angle Ar or the first compression stroke S12 after initiation of normal rotation of the decompression cam during the time period until the decompression cam reaches the second stop position, the decompression cam opens the exhaust valve and increases the run-up angle Aa of the crankshaft.