| 摘要 |
A method and apparatus are described for determining the cylinder mass of air M available for combustion in a crankcase scavenged, two-cycle engine 10, based upon the Ideal Gas Law relationship and indications of pressure P, volume V, and temperature T of air in the crankcase chamber 18, at predetermined points in the engine operating cycle. This is achieved by first determining the mass of air MT trapped and compressed in a crankcase chamber 18, and thereafter, determining the residual air mass MR remaining in the crankcase 18 after the transfer of air to the associated combustion chamber 40. Then, the actual air mass 17 transferred to the combustion chamber is determined as a function of the difference between the trapped and residual air masses. Engine trapping efficiency can be used to correct for air leakage from the combustion chamber 40 prior to cylinder exhaust port closure. The volume of the air within the crankcase chamber 18 is derived as a function of engine cycle position, with crankcase air temperature T being derived as a function of intake air temperature TIN. Air pressure P in the crankcase 18 is monitored with a pressure transducer 46. <IMAGE> |
