Why no two-stroke diesel cars? 4

[kj16v]

Hi all. I joined purely to ask this question:

I've just been reading about two-stroke diesel engines. How come there aren't any cars or road vehicles with this type of engine?

Also, there are plenty of cars with turbo-diesel engines. Why aren't there any cars with supercharged diesels?

Cheers

 

[SMOKEY44211]

Sort Block Assembly

 

[SMOKEY44211]

Preliminary head design.

 

[HRHtex]

Smokey - very nice drawings. Are you building this from scratch or adapting an existing engine?
I notice that your cam lobes are not "double-ended" - are they still half-speed?
That is a lot more than 40 cam degrees on those lobes - and a lot more than .190 lift.
How did you decide on 80 crankshaft degrees for your cam?
Are you intending to use a scavenge blower?
Sorry about all the questions.

 

[SMOKEY44211]

Hello Yes for the most part its a custom assembly. Block, head, crank, rods, pistons, ect. are being fabricated. However they are sized to use off the shelf components such as bearings, rings, valves, springs and so on. the drawing is incorrect as it relates to the camshafts. I'll post the updated version after the changes. The 80 deg. figure is not set in stone. The exhaust/ scavange event is 90 deg. as determined by the height of the sleeve porting. Most engines open the exhaust around 135 deg. ATDC so I used that as a good jumping off point. I am using a traditional rootes type blower for scavenging and possibly for some additional boost. I'm after fuel economy but testing will determine what the final configeration will be. Not much data base to draw from. Near as I can tell no one has attempted doing it this way. I think the idea has merrit so I'm putting my money where my mouth is. I'll post additional info as the project moves along.----Phil

 

[gruntguru]

Rotec convert 4 stroke diesels to 2 stroke using a piston scavenge pump timed to the engine. I think each piston serves two engine cylinders. The object is emissions reduction.

http://www.rotecdiesel.com/go.cfm?do=Page.View&pid=5

Engineering is the art of creating things you need, from things you can get.

 

[HRHtex]

Smokey - I too have never heard of a 2-stroke diesel with the intake through the valves and piston port exhaust. This is a bit surprising as "uniflow" steam engines have this layout.
Your engine may be worth putting in a provisional patent application - which is quite cheap if you do it yourself.
Personally I would mention in the application the possibility of operation without a scavenge blower and using much later intake valve closing in conjunction with a reed valve in each intake port.

 

[L4189]

After 80 years of development of the 2 stroke uniflow engine I think it will be hard to come up with something no one has thought of already. The use of a separate piston for a scavenging air pump was used on the earliest direct reversing 2 strokes built by Fairbanks Morse back in the '30's. There is a good reason why everybody went to positive displacement blowers as they are more efficient high volume air pumps.

 

[BrianPetersen]

With the 2-stroke diesel with intake ports and exhaust valves, it's easy to arrange for swirl of the intake charge (necessary for normal diesel air/fuel mixing and combustion processes). With intake valves and exhaust ports, not so much. Not impossible, just harder.

Some lube oil is inevitably going to get past the ports. It's an inherent situation with all piston ported 2-stroke engines. With intake ports and exhaust valves, that excess oil goes into the cylinder where it has at least a hope of being involved in the combustion process. With intake valves and exhaust ports, that excess oil is going straight out the exhaust (think about HC emissions).

 

[RPstress]

http://www.eurekamagazine.co.uk/article/29325/The-future-of-fuel.aspx?u=62299

some reported thoughts of Jamie Turner, a chief engineer at Lotus Engineering.

Doesn't look like this engine is anything other than a development idea.