A general purpose model of the internal combustion engine with time as the continuous independent variable has been derived for digital computer simulation. A significant advantage rests in the graphic display of maximum and minimum values of component forces and torques, or any model variable, as a function of crank angle. The differential equations of motion that describe component positions, velocities and acceleration were combined to describe the dynamics of the entire engine. Gas forces, as well as static, viscous and velocity-dependent friction terms, have been included. The IBM Continuous System Modeling Program (CSMP) was used to describe the engine and solve the equations. The model is easily adaptible to many engine configurations.