While the vortex design shows the heat release curve to be gradually rising well into the expansion stroke, the non-vortex counterpart appears to be losing heat by the declining percentage of fuel mass fraction burned (which is an artefact of the chosen expansion polytropic coefficient, since MFB% cannot physically decline by definition due to irreversible combustion).
As the expansion stroke proceeds, the mixture comprising burned gas products and unburned fuel in the divided chamber get transported through the side channels into the main combustion chamber, where there is oxygen present to react with the still hot residual hydrogen.
Neither n nor [gamma] remain constant throughout the compression and expansion strokes.
Neglecting the losses associated with mass transfer into and out of the cylinder after the early transient conditions have settled, the dissipated work per revolution is the difference between work done on the trapped gas during the compression and expansion strokes.
If the temperature change over the expansion is the same as during the compression, then over the compression and expansion strokes of one engine revolution:
These results are relevant because the Wankel engine, has a relatively larger SA/V ratio than a conventional piston engine, which is also true during expansion stroke of "X" engines, so intuitively could suffer from higher heat transfer losses.
In this case, the peak pressure was accurately predicted by CFD, with start of combustion and expansion stroke showing slightly higher pressure figures than experimental / GT-POWER.
The expansion ratio is based on the swept volume at expansion stroke [V.
This volume ratio is defined as quotient between the swept volume at expansion stroke and the swept volume at compression stroke:
The unique feature of the model is the simulation of simultaneous expansion and compression of the crankcase as the piston undergoes the compression and expansion strokes
It's just a better engine because of the additional flexibility and control you gain by separating the compression and expansion strokes
Honda has revealed the prototype of a revolutionary high-expansion-ratio engine featuring intake and expansion strokes
of variable lengths.