Sine-Wave Generator

The sine-wave generator indicates the piston position as a function of time. The piston motion is simple harmonic and goes between the top dead center (TDC) position and bottom dead center (BDC) position. At TDC the volume in the cylinder is the Clearance volume (33 ml for the engine) at BDC the volume in the cylinder is:

(Clearance volume + Swept volume).

These volume extremes correspond to the minimum and maximum output of the sine wave generator.

When a (p,v) curve is generated for the engine, the sine wave generator provides the v- signal and the cylinder pressure transducer the p-signal. Both of these parameters vary with time and data can be collected as p(t) and v(t), or as a (p,v) data set. Normally this type of data is collected over a small number of cycles for a selected engine condition.