Why not two-stroke cars?

Twas Sun, 7 Dec 2003 13:47:03 +0000 when Chris put finger to keyboard producing:

sound like a lawn mower?

actually I saw a small car the other day (well I heard it first) and I would swear it had a 2 stroke engine from the noise it was makeing...

-- Regards. Mark.(AKA, Mr.Nice.) ___________________________________________________________ "To know the character of a man, give him anonymity" - Mr.Nice.

mrniceATmrnice.me.uk

Relative lack of torque, emissions, maintenance costs.

The only reason why you'd want to build a 2-stroke is where weight and size is important. They're relatively light, simple and compact engines, but need to be run on expensive 2-stroke oil as well as needing more maintenance than the average 4-stroke vehicle.

Pollution I guess as 2 stroke mixture contains a % of lubricating oil

Weren't the old Wartburgs and Trabants 2 stroke?

Emissions and fuel consumption mainly. Because of the "total loss" lubrication system (the lubricating oil is burned with the fuel - hence the blue smoke), they're just not clean enough, even with the latest technology. They're also thirsty because there is a power (burn) stroke every crankshaft revolution instead of every other in a four stroke engine. This makes them powerful for a given cc though.

The two stroke design is all but dead now, even in the bike world. You can get a few 50's and 125's but nothing bigger now. The last "performance" 2 stroke (Aprilia RS250) was killed off earlier this year due to inability to meet emissions regs. Shame, as it made 60 bhp from just 250cc!

Dan

will know.

Some time ago I heard that Jaguar were developing a 2 stroke engine for use in their cars. Dunno what happened to it. Mike.

And don't forget the Saabs from the late 60s/early 70s.

There used to be some American 2 stroke petrol lorries as well... plus one of the tank designs used a two stroke diesel engine.

Probably a Ka with more than 40k miles....

;)

Also, most modern motorists are too neglectful of their cars and would never fill the oil up, and after a short while it would die.

"TMC" wrote in news:bqvd4v$cfg$ snipped-for-privacy@news8.svr.pol.co.uk:

And the old Saabs from the '60s. Remember seeing and hearing them on the RAC rally. And I think the Renault Dauphine was two stroke. Dave

will know.

loss"

fuel - hence

latest

Only if you assume that a 2 stroke car engine must have a petroil lubrication system.

As far as I can see, there is no practical reason why a 2 stroke engine can't have a conventional lubrication system the same as any 4 stroke car engine.

I feel sure that the Jaguar one I mentioned in my previous post, that they are or were? trying to develop, would have had a conventional lubrication system. Otherwise as others have pointed out, it wouldn't meet current emission regulations, and would just be a pointless waste of time, money and resources. Mike.

Says the chap too timid to meet Dervy.

The inlet gasses are circulated round the crankcase so pick up oil from the big end bearings and the spray from them onto the bores if these are pressure fed - unless you can think of a way of sealing this.

The fuel/oil mixture in a 2 stroke doesnt just stay in the top half of the engine,there is a good explanation of it here:

So,you can see from that, it would be very difficult to run a wet sump type lubrication system on a 2 stroke.It may be possible to run the crank and con rod bearings on a 4 stroke style oil system, but oil needed to lubricate the cylinder walls would be sucked into the combustion chamber and burnt, meaning the effect would be the same as the usual fuel/oil mixture used in 2 strokes. Alan.

Old SAABs were two stroke, then they started putting in a V4 (Ford?) four stroke motor.

Deltic was a 2 stroke diesel too. (very strange engine - three cylinders in a delta, hence the name, a crankshaft at each corner, and two pistons per cylinder going towards each other sharing the same combustion chamber. They were quite small for their power - originally aero engines.)

cheers, clive

petroil

stroke engine

4 stroke

half of the

wet sump type

crank and

needed to

combustion chamber

fuel/oil

Sorry, I don't follow that argument. It's true only if pressured crankcase air is used in the cylinder/s, as per a conventional 2 stroke. But that is not an essential function in a 2 stroke engine. There are other ways to achieve a pressured fuel/air mix into the combustion chamber, without taking air from the crankcase, so that needn't be a problem. I can think of 2 or 3 ways of doing it. Whether they are economic or good enough to be worth considering is something else, but they would work. Of that I'm positive.

The first post, from Michael from Bigenz in the link you gave above, also seems to indicate that the making of a 'clean' 2 stroke engine is not unachievable. Mike.

Opposed piston engine

Speaking of deltics

click "technical corner"

click "Power Units"

the railbourne version of the napier engine, 2×these engines fitted to locomotive for 3300HP and an impressive sound..

If thats the sort of thing that turns your crank!!

there is an impressive section on the rebuilding of a deltic engine here following an exhaust silencer fire when the fire brigade poured foam into the engine.....

incidentelly nearly 400 of the newsest 3300hp locomotives operating in this country are 2 stroke,

GM who build them have just had to redesign the whole thing to include a scrubber to clean the engine emmissions up for the forthcoming emmision regs

I've met you before? Havn't i?

You can still get blown diesel 2 strokes. There's no inherent reason you have to mix the oil with fuel, it's just difficult to keep the oil & the air seperate.