Patent ID: 6718917
Filing Date: 2004-04-13
Classification: F02B,F02F

Abstract:
A method for providing and operating a crankcase scavenged two-stroke internal combustion engine, the method comprising:providing a cylinder that defines a combustion chamber and that is configured to reciprocatingly receive a piston therein, the combustion chamber further comprising a scavenging air supply inlet, an air and fuel mixture inlet and an exhaust outlet; providing a fluid communication passage arranged between the scavenging air supply inlet and an inlet portion of each of a plurality of scavenging ducts thereby establishing a plurality of scavenging air inlet portions, one each of the scavenging air inlet portions to each of the plurality of scavenging ducts, and the scavenging air inlet portion to a scavenging duct being defined as an open area of the duct across which fluid communication is affected during a scavenging air filling process due to registration of the fluid communication passage with the open area of the duct; arranging the plurality of scavenging ducts to include at least an exhaust-side scavenging duct and a mixture inlet-side scavenging duct and wherein each exhaust-side scavenging duct has an exhaust-side scavenging air inlet portion and the mixture inlet-side scavenging duct has a mixture inlet-side scavenging air inlet portion; configuring the plurality of scavenging ducts to collectively contain a sufficient amount of air to assure that substantially only air exits the engine through the exhaust outlet of the combustion chamber during a scavenging process; and arranging the scavenging ducts so that an air and fuel mixture begins to be scavenged to the combustion chamber from the mixture inlet-side scavenging duct later than scavenging air begins to be scavenged to the combustion chamber from the exhaust-side scavenging duct.