Jay Leno's EcoJet: Soaring on a freeway near you? [Biodiesel fueled jet turbine automobile]

We first saw Jay Leno's EcoJet mid-engine turbine coupe at the 2006 SEMA Show in Las Vegas. Leno, with General Motors' Design Chief, Ed Welburn, and Frank Saucedo, who heads the automaker's west coast studio, penned the design concept.

Leno has both a motorcycle and a pickup truck powered by "jet" turbine engines, so the plan was to create an automobile that would run on a similar powerplant fueled by biodiesel.

The EcoJet was initially a static exhibit, but one thing about Jay's Garage is that everything runs. So Jim Hall, Bernard Juchli and the other wizards in the Burbank shop set about to turn the EcoJet from a barely rolling display into a complete running automobile.

What they were mating were a Honeywell LT-101 turbine engine with some 700 bhp and upwards of 500 lb-ft of torque to a GM 4-speed automatic transmission. This driveline was installed amidships in a reworked Corvette aluminum frame surrounded by the carbon fiber body.

Think about the challenge of turning a static show car into a running automobile. Problems like mating the electronics of the turbine to those of the gearbox and then creating a dashboard display so Leno can monitor functions when driving.

And all this while the crew was working on other projects from steam machines to muscle cars, because unlike some shops, in Jay's Garage things get done.

Now the EcoJet is a runner...like 150-plus mph in one test. We had a chance to spend a day with Leno and the jet machine and can confirm it is impressive.(continued)

A diesel-fueled turbine driving an electric generator would seem to me to be an ideal compact powerplant for vehicle applications.

I know Jay has a thing for old steam cars... A hi tech steam turbine electric hybrid could be very trick...

Using the hybrid type bank of battery would remove the one major steam problem ...the ramp up / down time of steam

Hybrid use a gas engine to run a generator that charges the battery's and the battery's run the electric motor... but do you need that fast on/off to charge batterys?

Use a steam turbine to run the generator that charges the battery's and the battery's run the electric motor

Steam turbine / electric drive train are a hundred + years old....but the battery bank storage buffer between is a new trick

I have long wondered why turbines aren’t used in trains, automobiles, and other motor vehicles. Turbines burn fuel constantly, and are therefore always producing power; in reciprocating engines, fuel burning starts and stops with each power cycle, making for increased complexity (fuel injection timing, linera-to-rotary power conversion, et al). Turbines also have only one moving part (the rotor) and one friction surface (the bearing),

The pulsating nature of the combustion in a piston engine has advantages of its own. Chiefly, it has the advantage that the pistons and valves - although subject briefly to the peak temperature of combustion - have a chance to dissipate that peak temperature between combustion cycles and therefore behave more like they are only subject to the average temperature. So that the piston engine can operate "continuously" in its pulsating fashion while the combustion gasses intermittently reach higher temperatures than a material under load can sustain continuously.
That is significant because the efficiency of a piston engine or a gas turbine is limited by the peak temperature of the gas. Although mechanically simple, a gas turbine has the problem that the turbine blades see the peak temperature of the thermodynamic cycle continuously, and the turbine blades are under load due to the centrifugal force concomitant to the high RPM at which they need to operate. The result is that it is challenging to get high efficiency out of a gas turbine. And that you will see combined cycles where a piston engine works in combination with a gas turbine to get efficiency and high power output. That is precisely what a turbocharged engine actually is - but you don't see a piston machine used to pump air into a gas turbine and to recover energy at low pressure and high volume coming out of a turbine, whereas you do see the opposite. So you should expect to see turbocharged engines take over as mobile power plants before you see pure gas turbines do so.
Gas turbines have of course taken over the commercial aviation market, but that is because they are so much more powerful than piston engines of similar size and weight as to be essential for use in the thin air at high altitudes. And because they work so much better in very low temperature air which predominates at high altitude - and because they are so very mechanically reliable (the one-moving-part thing).

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