How dose throttle position affect VE

[stefz]

Hi,
I'm trying to construct a VE map for Rpm vs. Throttle Position. Zetec 1.6L (Europe)

I have been working with Desktop Dyno 2000 to build a simple VE vs. rpm table, and now need to add throttle position into the equation.

The reason I need Throttle pos w/VE vs Rpm is that Im waiting for a Megasquirt EFI controller to arrive, and I will be using it to Fuel a 1600 Zetec engine, and as the Megasquirt soley uses VE tables to calculate fueling at a given rpm and them adjustments with MAP and Throttle pos, temp ect.., having a VE vs. Load map to work from will be usful in setting up the system and will save alot of time..

Any one who can help me with a formula to incorperate Throttle position and create a table (eventually 3d with MAP) VE map, will be most appeciated..

All the best

stef.

 

[WilliamH]

stefz,

What you need is a base fuel map. If you know of someone who has run one of these identical engines on an engine dynamometer with a user programmable ECU you may be in luck.

To generate any sort of usable fuel data map with equations based on throttle position derived VE is very presumptious. Ford engineers may be able to do so, based on past engine testing/development work with this engine.

I cannot give you any specific names (no promoting allowed) but, there are several engine testing companies in the US that could help you. Some have experience with the Zetec 1.6L. Try "fuel injection testing" in Google.

Will

 

[patprimmer]

WilliamH

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[EngJW]

I don't think VE is what you are after, if it is volumetric efficiency that you mean. VE is low at part throttle and it really only has meaning at full throttle. What you are building is a table of injector pulse width vs. rpm and throttle angle. This is the same as the base fuel table that Will described.

At part throttle and at a fixed rpm, the engine only knows how much power or torque it must put out to match the load. The throttle is opened ony enough to produce this amount of power. If combustion is not as efficient and the intake system restrictive, then more throttle opening is needed for the same load. The better the engine is tuned, the less throttle opening is needed. Thus, throttle opening is a dependent variable.

The flow area exposed per degree of throttle movement is also non-linear, so that must make setting up a table more complicated.

John Woodward