VE%
 

I was going through my Ultragauge and found the Volumetric Efficiency gauge. I did some research and for most cars the average 80-100%. In my car, going a constant speed it stays at 75%, so only 3/4 of the total space of the cylinder is being utilized, which seems lousy. The closer the percentage is to 100 the more power the engine produces, but would that mean more FE?
If so what are some ways to increase VE? Like would a better air filter help?

Regearing or going to a taller tire would boost VE at a lower RPM.
End result, better fuel milage.

Open the throttle all the way; that will help VE.

Pressurize the intake. A supercharger or a turbocharger are very good at this.

Note that with any of those you will be making more power, so you'll wind up accelerating. For going a constant speed, your VE is going to be lower.

-soD

Only time my VE shows that high at steady speed is on cruise going uphill.

But, at idle it shows 49 so not much difference.

The higher the VE the better your motor is at making power, but unless tuned for 1-2K rpm's at 100% VE, the higher number will equate to less MPG.

can not Measure VE
 

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

i don't know the conversion efficiency of an internal combustion engine to electricity and batteries, but this is the whole idea behind series hibrid systems. The engine is run constantly at peak effeciency, and it charges a battery. The vehicle is ultimately powered by electric motors.

Trains are series hybrids, and I often wonder if it's a good system for tractor-trailer big rigs.

...a series of automotive EQUATIONS worth studying:

T = 5252*HP/RPM

HP' = T*RPM/5252

HP" = (AP*CR*VE*CID*RPM)/(5252*150.8)

HP = (T*RPM/5252) = (AP*CR*VE*CID*RPM)/(5252*150.8)

VE = (T*150.8)/(AP*CR*CID)

...where:

T = torque, lb·ft
HP = horsepower
RPM = engine speed
AP = air pressure, psi (~14.7 psi)
CR = compression ratio
CID = engine cubic-inch-displacement
VE = engine volumetric efficiency, %

...use the HP@RPM and T@RPM values for your engine and backsolve for its' VE at those two operating points (remember it's not a constant, but varies with engine load and rpm).

Kiss