| 摘要 |
PURPOSE:To increase a supercharging effect and improve output by feeding an intake air to the amount of two stroke capacities which is taken in and compressed by plural pistons into one combustion chamber in a crankcase supercharging type four-cycle engine having plural cylinders. CONSTITUTION:When both of a pair of pistons 15, 16 are extended, an intake valve 3 is opened and an intake air is taken into a crankcase 4 from a carburetor 1 via an intake passage 2. At this time, since one cylinder 17 carries out an exhaust stroke while the other 18 carries out a compression stroke out of a pair of cylinders, an intake air to the amount of two stroke capacities is taken into the crankcase 4. Then, as both of the pistons 15, 16 are contracted, the intake valve 3 is closed and the intake air in the crankcase 4 is compressed by the pistons 15, 16. At this time, one cylinder 17 carries out an intake stroke while the other 18 carries out an expansion stroke out of the cylinders. Accordingly, the intake air in the crankcase 4 is sent under pressure into the combustion chamber 7 of one cylinder 17 via an intake passage 5.
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