An exercise in speculation, otherwise known as dreaming.
The other day I was surfing WikiPedia. (what? you don’t do that?) and I came across this:
extracts energy from a flow of hot gas produced by combustion of gas or fuel oil in a stream of compressed air. It has an upstream air compressor (radial or axial flow) mechanically coupled to a downstream turbine and a combustion chamber in between. “Gas turbine” may also refer to just the turbine element.
Energy is released when compressed air is mixed with fuel and ignited in the combustor. The resulting gases are directed over the turbine’s blades, spinning the turbine, and mechanically powering the compressor. Finally, the gases are passed through a nozzle, generating additional thrust by accelerating the hot exhaust gases by expansion back to atmospheric pressure.
Energy is extracted in the form of shaft power, compressed air and thrust, in any combination, and used to power aircraft, trains, ships, electrical generators, and even tanks.
Reading through the whole article was very interesting. Toward the end I come to what I caught my attention the most….from a trucking perspective.
Advantages of gas turbine engines
- Very high power-to-weight ratio, compared to reciprocating engines (ie. most road vehicle engines);
- Smaller than most reciprocating engines of the same power rating.
- Moves in one direction only, with far less vibration than a reciprocating engine.
- Simpler design.
- Low operating pressures.
- High operation speeds.
- Low lubricating oil cost and consumption.
and the downside? (there is always a downside)
Disadvantages of gas turbine engines
- Cost is much greater than for a similar-sized reciprocating engine (very high-performance, strong, heat-resistant materials needed);
- Use more fuel when idling compared to reciprocating engines.
Cost might be a problem with Millie Mini Van Mom’s econobox. Cost is a factor in trucking sure. But to replace my current engine would cost about $20,000. How much might a micro-turbine cost?
So, dreaming.
Of a turbo-electric hybrid?
Cool post!
I have often wondered why they didn’t put a turbine in a truck since I have gotten out of the military (I drove an M1 tank, turbine powered). After studying more about it, there are a few more reasons that a turbine would be a problem.
A turbine is quite efficient at a steady rpm. When you have to change the throttle setting a lot, like going up and down slight grades, it becomes much less efficient.
We haul engines for Northwest Airlines. One of their requirements to hauling an engine is that you cannot drive with chains installed or over “washboard” snowpack. Their concern is for the bearings in the engine. While operating, the turbine may have very little vibration, but it can’t withstand the same amount that a ICE can either.
With the new focus on “hybrid” technology, their may be a place for turbines there. A turbine that runs at a constant speed coupled to batteries to an electric motor to your drivetrain may be feasable.
Another area that may have some merit is in the APU market. Again, as a hybrid, or as straight power generation. Neither of which would require changing the running speed much.