| 摘要 |
A four-cylinder engine includes a cylinder body (3), a cylinder head (4), and an ignition device (27) including spark plugs (14). The engine also includes an intake device (16) connected to intake ports (9), an exhaust device (23) connected to exhaust ports (10), four pistons (6), and a crankshaft (8) connected to the pistons (6) by connecting rods (7). Explosion intervals of the four cylinders are 270°, 180°, 90°, and 180° as crank angles. The engine further includes an discomfort eliminator (35) which, when the engine speed is lower than a predetermined value, makes the indicated mean effective pressure of at least one of two cylinders having an explosion interval of 90° lower than the indicated mean effective pressures of other cylinders having an explosion interval of not 90°. This invention can provide a four-cylinder engine which causes unequal-interval explosions but produces little change in driving energy per unit time in an operating state in which an occupant is liable to feel torque fluctuations. |
