US Army Awards SBIR Contract for Waste Heat Recovery Using a SuperTurbocharger “Hybrid Engine”
14 April 2010
| The VanDyne SuperTurbo. Click to enlarge. |
The US Army SBIR Program has competitively selected and awarded a Phase 1 research contract to VanDyne SuperTurbo, Inc. for a project developing a waste heat recovery system using VanDyne’s SuperTurbocharger technology.
VanDyne’s SuperTurbocharger (SuperTurbo) is a turbocharger with an integral Continuously Variable Transmission (CVT). By changing the gear ratio of the CVT, the SuperTurbo is able to either pull power from the crankshaft to provide a supercharging function, or to function as a turbo-compounder, where energy is taken from the turbine and given to the crankshaft.
| The SuperTurbo concept. Click to enlarge. |
The SuperTurbo’s supercharger function enhances the transient response of a downsized and turbocharged engine, and the turbo-compounding function offers the opportunity to extract the available exhaust energy from the turbine rather than opening a waste gate. Effectively, says VanDyne, the SuperTurbocharger can create a “hybrid engine”—the combination of a piston engine working together with a turbine engine.
Work on the Army SBIR contract is scheduled to begin immediately and will be conducted in three phases; each phase award is pending the success of the previous phase. The program goal of Phase 1 and Phase 2 is to achieve a 7% increase in fuel efficiency as well as a corresponding 7% increase in maximum horsepower over the traditional turbocharged diesel engines within the US Army fleet.
In a paper being presented this week at the SAE 2010 World Congress, Chris Chadwell and Mark Walls from the Southwest Research Institute (SwRI) used 1-D simulation to show that a 2.0-liter I4 using a SuperTurbo could exceed the torque curve of a 3.2L V6, and meet the torque curve of a 4.2-liter V8 by using a SuperTurbo and a fresh-air bypass configuration.
In each case, the part-load efficiency while using the SuperTurbo was better than the baseline engine. For the bypass configuration, the full-load efficiency was better as well. The transient response of the system was similar to a naturally aspirated (N/A) engine, even at low engine speeds. Downsizing from a 3.2L improved fuel economy 17%, and downsizing from a 4.2L improved 36% on the NEDC driving cycle.
When implemented with a close-coupled catalyst and an air bypass configuration, where some fraction of the boost air bypasses the engine and is inserted into the exhaust in front of the turbine, the exhaust temperatures were air cooled so that fuel enrichment was not necessary.
The result was a gasoline engine that could run at high brake mean effective pressure (BMEP) at low engine speeds, and because of the special bypass configuration, can go to high loads with a single compressor. A bypass arrangement would not be possible without the supercharger function of the SuperTurbo.
Resources
Christopher James Chadwell, Mark Walls (2010) Analysis of a SuperTurbocharged Downsized Engine Using 1-D CFD Simulation. (SAE 2010-01-1231)
That's pretty clever, its been proposed that you could do a similar thing with an electric turbo / supercharger / super capacitors, but a mechanical connection might be more reliable. Although CVT's and 100,000's of rpms could have reliability issues.
Posted by: 3PeaceSweet | 14 April 2010 at 01:06 PM
Gearing the turbo back to the crank is not a new idea; The Wright 3350 aircraft engine used this device back in the '50s. A clutch was used as a safety device in case the turbo broke.
Posted by: Lad | 14 April 2010 at 02:39 PM
They should require all ICEs sold after 2011 to have these.
The price and reliability of hybrids and BEVs would skyrocket - relatively speaking.
Posted by: ToppaTom | 14 April 2010 at 08:00 PM
An experimental highpowed engine was built with the DELTIC engine combined with a jet engine as the turbo supercharger.
The electric turbo supercharger of the new OPOC engine provides the same function.
The steam diesel Kitson-Still locomotive could have a modern version with very high zero-speed torque and high energy density with an electric assisted air bearing supercharger from MITI.
Large lorries are now candidates for a Still cycle engine with electro turbocharging. ..HG..
Posted by: Henry Gibson | 15 April 2010 at 04:06 PM
Henry, try to pay attention.
Posted by: Engineer-Poet | 15 April 2010 at 08:15 PM
I think EP is right, although solid state thermo-electrics might have a future in mobile applications I think trying to use steam on road vehicles is a bit of a dead end. Although a combined cycle locomotive running on natural gas could be do-able but you would need an entire carriage for the extra equipment / fuel storage, better leave the power plant stationary and run the train on overhead wires in areas where it has to accelerate, the rest of the time it can cruise on a small diesel / hybrid system.
Posted by: 3PeaceSweet | 16 April 2010 at 03:15 PM
As stated above the concept is fine, but connecting something running at say 100,000 RPM directly to a slow moving engine might be problematic if the engine misfires! Just seems to me that an electric transmission between the two elements might be more immune to damage than a possibly momentarily jerky mechanical link.
Posted by: PaulT | 19 April 2010 at 09:18 AM
That's what torsional dampers are for.
Posted by: Engineer-Poet | 20 April 2010 at 09:57 PM
The high speed of the turbocharger is best coupled electrically to the drive train. An electric motor-generator stands between the compressor and the turbine wheel. In supercharging mode, the electric motor-generator powers the compressor while waiting for the turbine wheel to spool up. In turbo-compounding mode, the compressor is declutched from the motor-generator, and the turbine powers the motor-generator to produce electricity. Excess electricity can be fed to another electric motor-generator in the drive train to add power to the wheels. The drive-train motor-generator can also serve as energy recuperator during vehicle braking, and to allow the engine to be shut off during stop and low-speed cruise in order to save fuel.
Posted by: Roger Pham | 23 April 2010 at 10:33 AM