opposed piston diesel engines

[JRT]

Opposed piston engines date back to the 19th century (eg. Gilles of Cologne constructed an OP
single-cylinder engine in 1874), but seem to be attracting some renewed interest.


Napier Deltic design from mid-20th century:

The more recent OPOC that DARPA and TARDEC threw some money into:

[omon]

ussr used such engines quite a lot, but the problem is they are 2 cycle, and like most 2 cycle engines are horrible poluters. especially when we are not talking about chainsaw, or weed wacker, even 1 cyl 50cc scooter stinks and smokes a lot more than regular cars.

[JRT]

ussr used such engines quite a lot, but the problem is they are 2 cycle, and like most 2 cycle engines are horrible poluters. especially when we are not talking about chainsaw, or weed wacker, even 1 cyl 50cc scooter stinks and smokes a lot more than regular cars.

Those operate differently, like what you see below where the crankcase (lower region in this graphic) is used to charge the combustion chamber (upper region in this graphic) through the tranfer port. The mixture includes the lubricating oil with the fuel and air. And it uses an overly rich mixture (excess fuel) to cool the piston tops. The excess fuel and added lubricating oil lead to less complete combustion.

[Doktor]

Wankel out?



Every known and unknown design will hit the news anytime soon, but the reality is we will have batteries instead of petrol.

Maybe not we, but our kids or theirs for sure.

[Captain Worley]

The Wankel is very power dense, but has gigantic friction and heat rejection issues.

[bonehead]

My father in law worked on such diesels for trains. If I remember correctly They were powerful as hell but didn't hold up well. They also were hard to throttle down. The next time I see him I will hit him up on this.

[Chogy]

The wankel is very smooth and can rev very high, but fuel economy has always sucked a bit. But there's good power to weight ratio to be had. The Mazda 13b rotary was a popular choice for experimental aircraft that had need of high hp/w.

IIRC, a 4-stroke diesel is about as efficient as an internal combustion engine can be made, efficiency being defined as mechanical power output per mass of fuel burned.

[Doktor]

IIRC, a 4-stroke diesel is about as efficient as an internal combustion engine can be made, efficiency being defined as mechanical power output per mass of fuel burned.

That would be a diesel with turbo (most diesel car engines these days) vs "regular" petrol engine, I guess.

[rj1]

That would be a diesel with turbo (most diesel car engines these days) vs "regular" petrol engine, I guess.

Inline 6-cylinder diesel with turbocharger, exhaust gas recirculation, and selective catalytic reduction to cut down the emissions. Regular cars as of now don't have the EGR and SCR, they're both in semis. (Consumers would throw a fit over SCR, it's an aftertreatment system you have to fill a tank with urea that aids in burning up particulates.)

I worked for Cummins as a design engineer for 8 years.

[gunnut]

Wankel out?

[ATTACH=CONFIG]32752[/ATTACH]

Every known and unknown design will hit the news anytime soon, but the reality is we will have batteries instead of petrol.

Maybe not we, but our kids or theirs for sure.

Electricity is very hard to store, that's why battery technology still sucks. It's the easiest form of energy to transmit and convert.

Petrol products are very easy to store, but hard to transmit/transport compared to electricity. The ability to cheaply store energy is a huge factor why we still use petroleum products.

[Aryajet]

Also service infrastructure is huge factor for electric vehicles. I mean charging stations and other related power generating requirement. Charging normally take way too much time, in the future they must standardize the battery configurations, 5 total sizes may be and in service stations just swap the battery and go which should not take longer than filling up a fuel tank. This will require car manufacturers to make battery swapping quite easy and safe.

That day is not really far away, over $100 a barrel for crud oil makes approaching other energy sources more feasible specially if they are renewable and green.

[tankie]

]The wankel is very smooth and can rev very high, but fuel economy has always sucked a bit.[/B] But there's good power to weight ratio to be had. The Mazda 13b rotary was a popular choice for experimental aircraft that had need of high hp/w.

IIRC, a 4-stroke diesel is about as efficient as an internal combustion engine can be made, efficiency being defined as mechanical power output per mass of fuel burned.

The reason i binned my rx8 , brill car but i needed a bowser behind me .

[Captain Worley]

The reason i binned my rx8 , brill car but i needed a bowser behind me .

Ah...the RX-8. Known here in the South as The Torqueless Wonder.

Drop an LS-x in it, and you'd have quite the ride!

Mazda missed the boat by not putting the Mazdaspeed3 nill in the 8.