The mechanical part of an internal combustion engine has been modelled, using the Bond Graphs technique. Given the gas pressure inside the cylinder, the model provides the velocity and torque at the flywheel, as a function of the physical properties of the mobile parts of the engine.
The first model obtained was from the slider - crank mechanism for one degree of freedom, representing a mono cylindric engine. Using the modularity of the Bond Graphs technique, three identical models have been coupled, forming a four ILLEGIBLE
A valves' command system has been included and the damping coefficient, related with friction losses and the heat generation, was determined taking in consideration of the engine efficiency.
All the models have been simulated by computer and the results obtained confirms the experimental data known for commercial engines.