Kinematic submodel describing the chamber volume
Engine cycle modeling - Spark-ignition engines

Cycle calculations will take into account variations in chamber volume and its derivative as a function of crankshaft angle. The classic connecting-rod-crank system is widely used in today's context, but a very special kinematics (piston movement) could be envisaged, for example with a movement that accentuates the maintenance of a constant volume around TDC over time.

In any case, crank-rod kinematics provides the following equations.

• The chamber volume is expressed as : $V\left(\theta \right)=V_{\text{m}}+\frac{d_u}{2}\left(1+{\lambda }_{\text{v}}-\text{cos}\theta -\sqrt{{\lambda }_{\text{v}}^2-{\text{sin}}^2\theta }\right)$

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