Unfortunately, I avoided the opportunity to learn about these engines. My father ran some
3 cylinder 2 stroke diesels in earth moving equipment some years ago and was very happy with them. I believe they were turbocharged, but am not certain. They may have started with a pony engine but again am not certain.Can you fill me in on the details?
Nope, the Deltahawk uses a traditional Roots belt-driven blower for starting and low-rpm operation.
People should really study up on some of the things that have been done with turbo- and super-chargers for the past 60 years before getting carried away. For the last 20 years, for example, virtually all EMD locomotive engines (2-stroke diesels) have used a hybrid mechanical/turbo supercharger. At low power settings and during starting, a sprag (overrunning clutch) spins the turbocharger from the engine's own gear train, just like the old Roots blowers used to be turned. But when the power is increased, the turbine takes over and spins the compressor faster than the engine's drive, so the overrunning sprag releases and the turbo is fully powered by exhaust.
Proven, simple, no silly mechanical-electrical-mechanical conversions to go through. But the 2-stroke diesel is dead anyway. Conventional
4-stroke turbo-diesels are the present (except for ever-decreasing production of EMD 710 engines) and the future of diesel power.Why is the 2 stroke diesel dead? I know little about diesels, just the obvious, like no sparkplug.
Bob
High emissions and lower fuel efficiency compared with competitive
4-stroke dieselsIn order to get emissions down, a 2-stroke diesel engine has to be "overblown" so that an excess of fresh air is pushed through the cylinder to drive out the exhaust gasses fully, but doing that wastes mechanical power. So solving the emissions problem aggravates the efficiency problem and vice-versa. And also, 2-stroke diesels have a lot higher lubricating oil consumption rate than similar 4-strokes, and that aggravates emissions too.
The EMD 710 is the only remaining locomotive 2-stroke, and is being phased out by the EMD 4-stroke "H-series" engine. Detroit Diesel was the biggest maker of 2-strokes for trucks, earthmovers, yachts, etc. and they stopped 2-stroke production several years ago. And its been over 20 years since many 18-wheelers used Detroit 2-strokes anyway. Fairbanks-Morse still builds their opposed-piston 2-strokes for a few Navy applications and for stationary applications (flood control pumps, backup generators, etc.) and will probably continue to do so, but that's a pretty small market segment.
Since 2 NGs are aviation related, that is one area where the 2-stroke
*might* hang on longer because of its weight savings, but its ultimately probably doomed there also.MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.