By Splitting the Hot from the Cold, a New Engine Design Could Dramatically Boost Efficiency

By Clay Dillow Posted 02.23.2011 at 3:27 pm 10 Comments

The Tour Engine Tour Engine

We really ask too much of our internal combustion engines--compression needs a cool environment and combustion a hot one--and the compromises made to accommodate those demands lead to abysmal efficiency. So a San Diego-based company is turning that around by splitting the engine into two parts--a hot half and a cold half--to potentially boost efficiency by 50 percent.

A conventional four-stroke engine has four essential motions: the intake stroke where the piston draws in fuel (downstroke), the compression stroke where it packs the fuel (upstroke), the combustion or power stroke where the fuel ignites (downstroke), and the exhaust stroke (upstroke) that clears the leftovers from the cylinder and prepares for a new intake stroke.

The first two strokes work optimally in a cold environment, while the last two work better when the cylinder is hot. To compromise, the radiator is constantly channeling heat away from the cylinders, energy that is lost forever. Moreover, compression happens optimally in a small cylinder, combustion in a larger one with more space for the fuel-air mixture to expand fully (more energy is lost to heat as exhaust here). Again, the average piston size is a compromise between the two.

Tour Engine in San Diego is tired of compromising. Its Tour engine breaks down the strokes into two different but connected cylinders: a smaller cold cylinder for the intake and compression strokes feeds the compressed fuel into a larger hot cylinder for ignition and exhaust.

Where conventional engines would waste 40 percent of their energy to cooling and 30 percent more to exhaust (that’s right, your car is only converting about 30 percent of its fuel to actual work), the Tour engine, in theory, could immediately boost engine efficiency by 20 percent. Ultimately, engineers there think their tech could boost efficiency by more like 50 percent.

Splitting cylinder functions isn’t a completely novel idea, but the idea of separate hot and cold cylinders that optimize each stroke is pretty intriguing. The principle of splitting hot and cold components to optimize performance is explained in more detail below.

[New Scientist]

Previous Article: With the World's Largest Antimatter Trap, UCSD Scientists Aim to Trap a Trillion Positrons at Once

Next Article: Science Tricks the Brain into Experiencing Having Three Arms

10 Comments

Link to this comment

-my name here-

02/23/11 at 3:39 pm

first line: too much OF our...

Link to this comment

eregorn8

02/23/11 at 5:05 pm

Great choice of a video... It took me a moment to understand but when I did, I laughed.

Link to this comment

jefro

02/23/11 at 5:58 pm

Pffssst! Looks like a supercharged two stroke engine to me.

Nothing new.

Link to this comment

dlapham

02/23/11 at 6:10 pm

Jefro: I was going to say exactly the same thing before I saw your comment. It looks like the same setup as a supercharged two stroke diesel. It just uses a piston type compressor instead of a roots or screw type. It also injects the fuel into the intake of the compressor and uses spark ignition. Otherwise it is just 100+ year old two stroke diesel technology.

Link to this comment

Brett Warkoski

02/23/11 at 9:35 pm

This is a unique engine. I hope that the fuel industry doesn't get mad at our cool technology.

Link to this comment

RDZombie

02/24/11 at 1:37 am

YOURE KILLING INDEPENDENT GEORGE

Link to this comment

Geawiel

02/24/11 at 4:08 pm

Absolutely perfect choice of video to go with this story lol. As for the engine itself, a number of questions come to mind. Is there any loss in HP or torque? What would be the mechanical upkeep for repairs? How reliable would the engine be? How expensive would it be to mass produce? How much room would the engine take up in the vehicle? I'm sure if I took the time, I could sit and think of more.

Don't get me wrong though, I feel our current engines could be much more efficant. I'm just not usually optimistic when something like this comes to light.

Link to this comment

ford

02/25/11 at 5:27 am

Hi guys

Wouldn't it be smarter if before shooting in the dark advocating why this engine idea may not hold water one would learn a little more through the company site ?

Link to this comment

PluginElectric

02/25/11 at 10:08 am

Too late!

Link to this comment

Rusty_Battleaxe

02/27/11 at 3:08 am

i remember seeing something like this a long time ago, except it used a 6 stroke engine and pumped water in to the chamber to use the excess heat for steam pressure. the guy patented it but i guess it never took off

Popular Tags

Science

All Tags All Photos All Videos

Science

+ More Photo Galleries

June 2013: American Energy Independence

Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.