Method and apparatus for determining air mass in a crankcase scavenged two-stroke engine.

摘要

The mass of air M available for combustion within a cylinder 14 of a crankcase scavenged two-stroke engine 10 is obtained by estimating the mass of air M trapped within a crankcase chamber 18, prior to its transfer to the associated cylinder combustion chamber 40. The estimate for air mass is derived from the product of pressure P of the air in the crankcase chamber 18 and the crankcase chamber volume V at a selected engine cycle position during that portion of the engine cycle when the air is trapped and undergoes compression within the crankcase chamber 18 divided by a factor containing the trapped air temperature T at the selected engine cycle position. <IMAGE>