---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Sat 02/07/04: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:33 AM - Re: Diesel torsional vibrations (Gary Casey) 2. 06:25 AM - Re: DynaCam, was alternative diesel engines (Dennis O'Connor) ________________________________ Message 1 _____________________________________ Time: 05:33:32 AM PST US From: "Gary Casey" Subject: Engines-List: RE: Diesel torsional vibrations --> Engines-List message posted by: "Gary Casey" <> Yes, pretty much true. Of course, in actual practice the homogenous-charge (gasoline) engine has a controlled burn, not an "explosion", but that's beside the point. By definition and in theory the so-called Otto cycle has a constant-volume combustion process while the official Diesel cycle has a constant pressure process. In reality they don't behave like their definitions. The spark-ignition engine has a combustion process that takes many crank degrees to complete, rounding off the pressure rise in the cylinder. The diesel process, because of the ignition delay of the fuel, inevitably is characterized by a very sharp initial pressure rise. The rest of the combustion might continue for some time as the fuel is injected, but the "damage" is already done. And combine that with the high initial pressure because of the high compression ratio the diesel will have a much higher peak pressure accompanied by a steeper pressure rise with the end result that the torque profile is much worse than for a typical gasoline engine. The peak pressure in a gasoline engine is typically 800psi or a little more while the peak pressure in a diesel is at least 1200psi, going up to over 2,000 for modern engines. Gary Casey ________________________________ Message 2 _____________________________________ Time: 06:25:00 AM PST US From: "Dennis O'Connor" Subject: Re: Engines-List: DynaCam, was alternative diesel engines --> Engines-List message posted by: "Dennis O'Connor" Yeah, it's a shame because the engine seems to have advantages and no real engineering show stoppers that I have heard about... They have been languishing so long now, that they have lost credibility, though... To get going again, they need to put some engines onto flying airframes - even if they have to give a couple of them away just to get them flying... *** if I were the principle invester I would cut a deal with Van's RV to get two of them in the air, even if I had to pay Van to do it! But then, I have been in business all my life and I have learned what it takes to stay in business *** I have no details on the current status as I have no interest in chasing rainbows... However, there are people in the experimental movement that if they pooled their money and their expertise (owning a machine shop, etc.) and acquired the right to produce and put a pair of those engines on airframes and generate interest, I feel that sales would follow... But it has to be a situation where the principal investors can substitute sweat equity for money by machining engine parts when their other work is slow, etc., so that they don't have to have 60K an engine to break even... denny ----- Original Message ----- From: "Johnny Johnson" You mention that they may be trying to get some engines out in > the experimental arena... that is of interest to me if it is more than just > a ploy to get investors. Any details would be appreciated. >