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Turbo/Super chargers do not improve engine efficiency (more power with the same amount of fuel). They improve VOLUMETRIC efficiency. To put it plainly, they all

Turbo/Super chargers do not improve engine efficiency (more power with the same amount of fuel). They improve VOLUMETRIC efficiency. To put it plainly, they allow you to shove more fuel into the same size engine. To burn more fuel you need a lot more air, hence the compressor. The same engine produces more power by burning more fuel per unit time. As far as the 10% fuel economy improvement (i.e: 20 to 22 mpg) by combining cylinder shutdown with electric turbo is concerned, well, I'll give them the benefit of the doubt and remain very skeptical. Do any of the claims account for non-trivial compressor motor power? If we dig deep enough are we going to learn that this company got a huge grant from the EPA? It feels like the whole business of solar bike paths in Holland. It's been a long time since I studied Thermodynamics. From what I recall engines are cycle limited and modern designs are optimized as far as you can go without resorting to esoteric optimizations. In other words, as long as you have an Otto cycle engine that's your limit. I seem to remember 18% max thermodynamic efficiency for Otto cycle under ideal conditions. Stirling cycle can do 90% efficiency, again, from memory.

drmilsurp 12y ago
I think the theme is really power on demand. I don't like the idea of an electric turbo/compressor for the same reasons I don't like quartz watches. But maybe adding an electric compressor and upgrading the already taxed alternator will offset the parasitic loss?. Performance and economy are in opposition. It is still all down to Air/Fuel/Spark. You just know that 10% was from DI and fuel cut on the odd cylinder in spite of the eturbo. When you open the throttle plate 100% and get that turbo of any kind running 100K+ rpms, ignition advance drops, fuel flow jumps and there goes your fuel economy. Again, you cut the fuel when you don't need it and/or stop spraying fuel everywhere else but directly in the chamber. Where you fall on the curve before/after MBT can be changed but it's not really possible to run after (lean side) the fuel curve with standard fuel stocks and certainly not under boost, ie you can do it, but you won't be making any power.

drmilsurp 12y ago

I think the theme is really power on demand. I don't like the idea of an electric turbo/compressor for the same reasons I don't like quartz watches. But maybe adding an electric compressor and upgrading the already taxed alternator will offset the parasitic loss?. Performance and economy are in opposition. It is still all down to Air/Fuel/Spark. You just know that 10% was from DI and fuel cut on the odd cylinder in spite of the eturbo. When you open the throttle plate 100% and get that turbo of any kind running 100K+ rpms, ignition advance drops, fuel flow jumps and there goes your fuel economy. Again, you cut the fuel when you don't need it and/or stop spraying fuel everywhere else but directly in the chamber. Where you fall on the curve before/after MBT can be changed but it's not really possible to run after (lean side) the fuel curve with standard fuel stocks and certainly not under boost, ie you can do it, but you won't be making any power.