Patent Document ID: 8725385
Application ID: 12713102
Patent Flag: 1

Claim One:
1. A method for computing mean effective pressure in an internal combustion engine, said method comprising: defining a sampling resolution for a series of sampling events, said sampling resolution being an amount of crankshaft rotation between the sampling events; computing and storing a volume array, said volume array containing combustion chamber volume as a function of crankshaft position for each sampling event; computing and storing arrays of a first and a second volume-related variable, said volume-related variables including values for each crankshaft position corresponding to the sampling resolution; where the first volume-related variable is defined by the equation: G k = V k + Δ ( n - 1 ) · ( V k + Δ n - 1 1 Δ ⁢ ( ∑ j ∈ [ k , k + Δ ] ⁢ V j n - 1 ) - 1 ) and the second volume-related variable is defined by the equation: H k = V k ( n - 1 ) · ( V k n - 1 1 Δ ⁢ ( ∑ j ∈ [ k , k + Δ ] ⁢ V j n - 1 ) - 1 ) where k is sampling event number, n is a ratio of specific heats, Δ is the sampling resolution, and V is combustion chamber volume from the volume array evaluated at any sampling event k; running the engine and taking a cylinder pressure measurement at each crankshaft position corresponding to the sampling resolution; storing the cylinder pressure measurement for a current sampling event and the cylinder pressure measurement for a previous sampling event for calculation purposes; and computing mean effective pressure for an engine cycle using an indirect integration calculation, where the indirect integration calculation is a function of the cylinder pressure measurements, the first volume-related variable, and the second volume-related variable.