hit and miss engine efficiency

If you were to be inclined to adapt a hit-miss to an automobile, I think the best approach would be to go with some type of electric hybrid. Flywheels are fine for storing energy, but it's a little difficult at getting that energy back on demand and at a variable rate. If you coupled the hit-miss with a generator, you could then route just the amount of power you need to the wheels and send the rest to a small battery pack to deliver peak power when needed. The hit-miss could just sit there doing it's hit miss thing at a constant RPM. Sort of what they do with diesel-electric train locomotives.

actually, the jake brake operates by holding the exhaust valve closed until the engine hits TDC and then opening the valve to release the pressure, then closing it, again, so the cylinder is under vacuum. in comparison, the hit and miss engine never compresses or produces vacuum, unless the governor calls for a power stroke. a better comparison is how a GM V-4/6/8 operates - holding the valves open on the unused cylinders to reduce pumping losses.

the option I'd thought of was a CVT drivetrain. a heavy flywheel could give regenerative braking, but you could probably get better weight efficiency with the hybrid.

The problem with our friend from the old board is that while the engine may be most efficient at WOT, the whole car as a system is not. Say the engine is a WOT, but the tranie is only in 2nd out of 6 gears, obviously it isn't the most efficient setup for the system. Additionally, the faster the car goes, the more aerodynamic drag, so the more energy is needed to maintain speed.

I'm not even sure about WOT being the most efficient point for an engine. Yes you are minimizing throttle loses, But if it were the most efficient point, why is it not used commonly? There are plenty of cars that can hold the engine at a relatively stable speed and vary other factors as they drive to give the desired speed. The idea being to hold the engine at a it's most efficient point. It's common with Hybrids and high efficiency (CVT) cars. My old '14 Honda Civic with CVT would hold around 1500-1750 RPM and let the CVT vary to whatever speed I wanted.

The first problem I can see with TLW's idea is that it takes more energy to accelerate than to maintain a speed. So a Hit & Miss cycle would loose momentum as it coasts which would have to be recovered. The shorter the cycle, the less loss.

I would go with a electric hybrid design. Flywheels are best in stationary setups. They are heavy, so it would take a lot more energy to get the car moving. Flywheels don't like to be maneuvered. Such a flywheel would have a major affect on handling. The Ol' Newton's 1st Law of Motion thing.

the problem with the disparity in engine efficiency is we want cars that can go faster than they should. the idea behind a lot of these new city cars, like the smart, and the Ford Transit Connect is to make a car that has a much lower top speed, so it is operating at its best engine efficiency closer to the normal cruising speed.
to be clear, his statement was that the engine is at its peak efficiency it can't accelerate any more - which made no claims of whether drag was increasing the load sufficiently to reduce VEHICLE efficiency.

as for the flywheels, I remember someone writing about the headaches involved with somebody's flywheel buses.

whihc brings up the question of whether it would be possible to build a machine with a gyrosocopic drivetrain. I'm sure it would be terribly funky and inefficient, but could you use a gyroscope to turn a wheel instead of a merry go round.