Paragraphs

Claims

p = compression ratio

V1 = displacement of the larger cylinder of the paired cylinders.

V2 = displacement of the smaller cylinder of the paired cylinders.

V1/V2 =ratio betwwen the displacements on the paired cynlinders

α = lead angle of the crank of the short-stroke crankshaft

ve = clearance space of the paired cylinders required for gas transfer without excessive lamination.

(α minimun) = lead angle of the crank of the short-stroke crankshaft, at the start- of-travel of the variably timed transmission.

(α maximun) = lead angle of the crank of the short-stroke cranskshaft, at the end-of-travel of the variably timed transmission.

Va (α minimun) = additional volume added to the clearance space, at the start-of-travel of the variably timed transmission, defined by the minimum lead angle of the crank of the short-stroke crankshaft, when the crank of the long-stroke crankshaft is located at its top dead center, at the end of the compression phase.

Va (α maximun) = additional volume added to the clearance space, at the end-of-travel of the variably timed transmission, defined by the maximum lead angle of the crank of the short-stroke crankshaft, when the crank of the long-stroke crankshaft is located at its top dead center, at the end of the compression phase.

Vr (α minimun) = compressed air volume at the start-of-travel of the variably timed transmission, defined by the minimum lead angle of the crank of the short-stroke crankshaft, when the crank of the long-stroke crankshaft is located at its bottom dead center, at the end of the intake phase.

Vr (α maximun) = compressed air volume at the end-of-travel of the variably timed transmission, defined by the maximum lead angle of the crank of the short-stroke crankshaft, when the crank of the long-stroke crankshaft is located at its bottom dead center, at the end of the intake phase. Compression ratio characteristics and formulas of the variable volume combustion chamber engine.

( V1 + V2 ) x number of pairs of cylinders = engine displacement.

V1 + [ V2 - Vr (α) ] x number of pairs of cylinders = displacement of the engine defined by the lead angle of the variably timed transmission.

theoretic compression characteristic of the engine after definition of the compression ratios established by the lead angle of the variably timed transmission.

definition of the maximum compression ratio at the start-of-travel of the variably timed transmission. In practice, Vr (α minimum) should not be deducted from V2 as it is too negligible.

definition of the minimum compression ratio at the end-of-travel of the variably timed transmission. In practice, Vr (α maximum) should not be deducted from V2 since the air mass admitted in V1 and V2 depends on the stored calibration at the maximum supercharging pressure.

A simplified formula of the compression ratio may be assumed depending on whether Va(α) is located at any angular position between the start-of-travel and the end-of-travel of the variably timed transmission, which is :

Claims