[Diy_efi] Intro, and q's about fuel economy

[Alexei Pavlov]

pedward at apsoft.com wrote:
> 
> > What the EGR really does is reduce the pumping losses at cruise due to
> > throttling.
> 
> It's simpler than that.  The exhaust gases already have fuel in them to
> some degree.  You recycle that in place of actual fuel.  The only way to eliminate
> throttle losses is to have no throttle at all.  You then do the throttling via
> modulation of the valve timing.

Could you explain why there are no pumping losses with variable valve
timing or clearance ?
I see variable valves exactly like throttles, the piston still has to
pump the vacuum to reach the BDC. The energy loss is still here.

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