If you're looking for a career in diesel technology, you don't necessarily have to become a mechanic or an engine calibrator. Colleges offer students the chance to learn many different aspects of the diesel engine, and upon graduation you could be a mechanical engineer, electrical engineer, physicist, or chemist fighting off job opportunities you may only dream of today. Recently, Diesel Power visited the University of Southern California's Combustion and Fuels Research Laboratory. We caught wind that it was experimenting with plasma ignition in order to develop a better way to burn bunker fuel in large shipping vessels. Kenneth Koo of the Tai Chong Cheang Steamship company pledged $4.1 million to fund the diesel and plasma ignition research headed by Fokion Egolfopoulos and Martin Gundersen. Diesel Power asked to come take a look.
| diesel Power plasma Ignition Testing plasma
The Physics of Diesel Power
Did you know that if you lit a flame in zero gravity it would burn complete, blue, and in the shape of a sphere? It's ironic that we have a clear picture and deep understanding of galaxies millions of light years away, yet we know little about combustion right here on Earth. That could all change when the University of California's Combustion and Fuels Research Laboratory (CFRL) gets its Opposed-Burner Configuration facility up and analyzing combustion characteristics.
| University of Southern California student Esin Sozer showed us the high-power plasma switches she was working on. Before touching the high-voltage device, she discharged residual electricity with a grounding wand isolated with glass. Other students working on the project include Dan Singleton and Scott Pendleton who told us that plasma initiates ignition through electronically excited species rather than heat. Also, the dramatically reduced ignition delay improves combustion efficiency.
The Test Chamber
The test chamber looks similar to a fire hydrant with four viewing windows where the hoses would normally connect. These four portals house laser diagnostics as well as sampling devices in order to capture a digital slice of the combustion (similar to a microscope's slide). The top burner directs hot air at a specified and controlled temperature. The bottom burner directs either liquid or pre-vaporized fuel and nitrogen gas. An ignition spark, plasma generator, or thermal ignition starts the controlled and easily varied reaction. In the middle is where this reaction takes place and the event is recorded. The reason for this setup, versus even a single-cylinder test engine, is its ability to isolate conditions and test one thing at a time. Using this technology, scientists can quickly evaluate numerous combustion changes and engine characteristics in their lab.
| diesel Power plasma Ignition Testing chamber
Jason Sanders is an electrical engineer in the making. His research focuses on controlling the combustion-inducing plasma discharges, which happen very fast-we're talking less than 100 nanoseconds. A nanosecond is one billionth of a second or 0.00000001 second.
| diesel Power plasma Ignition Testing electrical Engineer
What Is Plasma?
If you've ever used a plasma cutter or turned on a halogen light-you've experienced plasma. Researchers also use plasma in medical treatments, the biofuel industry, and wine making. The simple definition of plasma is: charged ions in a gas stream, or the fourth phase of matter.
How A Plasma-Fired Diesel could Work
1. The intake valve opens, the piston travels down, and air enters the combustion chamber.
| diesel Power plasma Ignition Testing plasma Process
2. The intake valve closes and the piston travels up, compressing the air. Normally, the combustion event begins during the end of this stroke, which is not optimum because the combustion is fighting the piston's upward movement and heat from the fuel is wasted.
3. The piston reaches top dead center and plasma is created in the cylinder (the glow plug could be made into the plasma source), initiating combustion. Since ignition delay (the time it takes for the fuel and air to mix) is greatly reduced, the total power of the fuel is released on the downward moving piston.
4. The last stroke shows complete nearly perfect combustion, and therefore no aftertreatment, EGR, or exhaust-mounted catalyst is needed.
Benefits:
• More power
• More fuel economy
• More engine RPM
• Better throttle response
• Elimination of
cold-start issues
• Lower static compression
ratio becomes an option
• Cleaner emissions, with
no expensive
and complicated aftertreatment
