Method for estimating pumping loss in an internal combustion engine

Method for estimation of the pumping torque of a fuel injected external combustion engine controlled by an electronic calculator based on the variation in cylinder volume and the differential pressure between the manifold (Pcol) and the exhaust gas (Pex). The calculator determines the product of the differential pressure and the change in cylinder volume multiplied by a shape coefficient. The coefficient is related to further coefficients dependent on the differential pressure and the rotational velocity of the motor and manifold pressure.