| 摘要 |
PURPOSE:To both increase compression ratio of an engine and improve its fuel consumption, by locating a valve of the plural intake valves to the center of a bore, protrusively deviating a valve seat of said center located valve into a combustion chamber and forming the center part of the bore to a shallow shape. CONSTITUTION:Four intake valves 16A-16D are parallelly provided to one another in a state of tilting for a cylinder 10, and one intake valve 16A of these valves is arranged on the center 12 of a bore. Here a valve stem 30A of the valve 16A is formed longer than that of valve stems 30B-30D of the other valves 16B-16D, while a valve seat 44A is deviated in a combustion chamber 23 from the other valve seats 44B-44D. In this constitution, the center part of the bore in the combustion chamber 23 can shallowed, accordingly compression ratio is increased, simultaneously S/V ratio (combustion chamber surface area/volume Ratio) can be decreased. |
