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In an old article by a gent who was rebuilding a dyno at the University of Maryland, he found that using a mid 80s GM 2.5 4 cylinder, when you increased the load from 20 to 50 HP the fuel consumption only increased by 50% while the power generated increased by 150%.
That's the "majic of high VE", an operational tactic that uses as close to possible to a 0 manifold vacuum or 100% MAP as possible under all of the vehicle operatinal parameters, without enrichment.
In order to do this you must incorporate some form of energy storage to separate engine load from vehicle speed, but this is where you incur losses that in most systems eliminate the advantage of an all or noting max VE tactic.
This is the reason I advocate hydraulics for storage and application. Since max VE can more than double the power per BTU in energy conversion, and hydraulic systems are at close to 80% right now, and have been for a decades, the development of new designs that increase that efficiency beyond 80% would have a dramatic effect in overall mileage from just a few percentage points in increase.
Pulse and glide maximises VE by employing an all or nothing engine operation. The real secret in the future will be to do exactly the same thing, WITHOUT A CHANGE IN VEHICLE SPEED. This requires storage and application of energy in an environment of constantly changing storage pressures with infinitly variable ratio machines. Accumulators can reach 99% efficiency and pumps are close to that as long as you keep their RPM below 1000 (wheel speed works great).
It's getting very close to reality.
regards
Mech
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