-   EcoModding Central (
-   -   Have You Guys Seen This One? (

Big Dave 01-07-2016 03:51 PM

Have You Guys Seen This One?
A spark-ignition engine with the efficiency of a diesel.

Itís rather like taking the Atkinson engine to the next level. A great deal more expansion than compression.

Back in the late 40s, aircraft engine designers played with turbocompounding Ė using expansion turbines to wring every last bit of work out of a pound of hot exhaust gas. And it worked, sorta. The engines of Shackleton bombers and B-29s were marvels of thermal efficiency. But they werenít reliable. They relied on gear reduction to match turbine RPM with engine RPM. Those stressed out gear trains were more of a danger to B-29 crews than Zeros.

Even earlier steam locomotives used compounding. The exhaust steam from one cylinder was ducted into another (larger diameter) cylinder and allowed to expand some more. This worked but they were tricky to operate using 1920s controls.

But this uses the older idea to make an engine that does not have a stressed out system.

Ilmor is highly respected in the auto world.

RustyLugNut 01-07-2016 04:27 PM

This has been around a few decades.
I'm not sure it is going to be a market success but their mention of it's use in hybrid drives and stationary power applications shows they understand the limitations of the engine.

solarguy 01-07-2016 04:34 PM

ferd. porsche tried it too...
Ferdinand Porsche tried something similar, with some pistons super charging other pistons.

I think it was given up as overly complex and had overheating problems.

I just bought a Mazda 3 with the Skyactiv system. Instead of typical gasser compression ratio of 9:1 or 10:1, the US version has 13:1, and the euro or japanese version is 14:1.

To prevent engine destroying pre-ignition, they use active changes in the cam timing.

So far, it works a treat.

darcane 01-07-2016 04:44 PM

Hmm... That looks very familiar, but not from the same company. I can't remember where, but I'd put money on this not being a new idea.

redpoint5 01-07-2016 05:21 PM

Seems a good idea. What are the limitations?

darcane 01-07-2016 06:57 PM


Originally Posted by darcane (Post 504089)
Hmm... That looks very familiar, but not from the same company. I can't remember where, but I'd put money on this not being a new idea.

There we go. Nearly identical design circa 1879:
The Deutz compound engine: 1879

Patent issued to a Gottlieb Daimler (yes, that Daimler). Link above has a variety of other similar designs for compound engines. I believe these were popular back then since metallurgy wouldn't allow for the high compression of modern engines, so alternatives were needed to harness more energy from the fuel.

All times are GMT -4. The time now is 09:56 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright