| 摘要 |
PURPOSE:To simplify structure of an unoperation mechanism and decrease pumping loss, by providing suction systems at every couple of cylinders wherein ignition sequence is in the order as of every other cylinder so as to cut air suction with one of the suction systems under a low load condition, and also providing a check valve at exhaust systems of an operational cylinders. CONSTITUTION:In a four-cylinder horizontal opposed type engine, first and third cylinders 4a and 4c are horizontally disposed on the left side, and second and fourth cylinders 4b and 4d are disposed on the right side at positions opposite to the cylinders 4a and 4c. Ignition sequence is set to 1 3 2 4. There are provided independent carburetors 8 and 11 and air intake pipes 9 and 12 at every couple of cylinders wherein the ignition sequence is in the order as of every other cylinder, that is, a couple of the first and second cylinders and the other couple of the third and fourth cylinders, and the third and fourth cylinders are rendered unoperational by closing a throttle valve 10 of the carburetor 11 under a low load condition. Further, a check valve is provided in exhaust systems of the third and fourth cylinders, so as to prevent counterflow of air upon opening of exhaust valves and reduce pumping loss during an exhaust stage. |
