Lotus omnivore, a piston engine that'll eat anything

[Hunid Racks]

http://jalopnik.com/400401/the-lotus...l-eat-anything

Lotus Engineering, in collaboration with Jaguar, is starting up a project they're calling "Omnivore," a task which, if successful, could see traditional internal combustion engines go the way of the dodo. Lotus is planning to meld the two-cycle engine with new technologies — direct injection and a variable compression ratio — to create an engine able to run on almost any fuel. If you've ever wondered what the future of the internal combustion looked like, you're getting a peek now. Put your propeller cap on and join us for a pocket protector talk after the jump.

Used to be that a gas engine was a gas engine and a diesel was a diesel. With the advent of reliable direct injection, variable displacement cylinder heads that don't turn into grenades, and incredibly sensitive monitoring and control systems, it's now possible to run an engine in ways would have never worked in the past. Consider the main barrier to high-compression gasoline engines in the past — preignition. High octane numbers were a band-aid for that problem, but that also caused fuel economy to plummet. Direct injection virtually eliminates the issue, allowing engineers to put the fuel right into the chamber exactly when it's needed, high pressure be damned. It's even conceivable to run a gasoline engine on the diesel cycle with direct injection. ......

Forget what you "know" about two strokes, if you direct inject them, they can have a sealed crankcase.

[Slideways]

In the photo they show overhead valves. How can you have two strokes with overhead valves without either blowing through a bunch of air (essentially running enough boost into the cylinder it pushes out the exhaust while there's valve overlap)? The site doesn't explain very much.

Oh, I see now that the photo is from Wikimedia and it's of BMW direct injection.

OK, I'm still curious.

[johnstarnes]

I wonder if it would run well on hydrogen?

[Smaart Aas Saabr]

Originally Posted by Slideways

In the photo they show overhead valves. How can you have two strokes with overhead valves without either blowing through a bunch of air (essentially running enough boost into the cylinder it pushes out the exhaust while there's valve overlap)? The site doesn't explain very much.

Oh, I see now that the photo is from Wikimedia and it's of BMW direct injection.

OK, I'm still curious.

Poppet valve 2-strokes (especially diesels) have been around for some time. Basically it works exactly as you say

When you use direct injection with a 2 stroke, you can scavenge with pure air, thus run too much air and get good scavenging, then close valves and inject fuel. This basically solves the big 2-stroke problem where you shoot some air + fuel, and half of the exhaust gets pushed out, with half of the fuel

Since diesels are all direct-injection or similar, the 2-stroke diesels just put a honking big supercharger (eg the "6-71 blower" on all those musclecars, well this is the supercharger off a Detroit Diesel 71-series engine) and that worked well.

Poppet valves also mean you can have a open crankcase w/oilpan, so you would just change oil like a 4-stroke with neat gasoline (or diesel) fuel

Thing is half the greatness of 2stroke is you can forget the valves...

[johnstarnes]

Originally Posted by Smaart Aas Saabr

Poppet valve 2-strokes (especially diesels) have been around for some time. Basically it works exactly as you say

When you use direct injection with a 2 stroke, you can scavenge with pure air, thus run too much air and get good scavenging, then close valves and inject fuel. This basically solves the big 2-stroke problem where you shoot some air + fuel, and half of the exhaust gets pushed out, with half of the fuel

Since diesels are all direct-injection or similar, the 2-stroke diesels just put a honking big supercharger (eg the "6-71 blower" on all those musclecars, well this is the supercharger off a Detroit Diesel 71-series engine) and that worked well.

Poppet valves also mean you can have a open crankcase w/oilpan, so you would just change oil like a 4-stroke with neat gasoline (or diesel) fuel

Thing is half the greatness of 2stroke is you can forget the valves...

I am amazed by just how much you know about how car engines work as I have always focused on the sheetmetal.

[khooper]

I hope IC engines have a future....after all, what are we going to do with all that oil if they don't? Oil is a resource meant to be used, like any other resource. Preferably responsibly
__________________________________
tips:always check the exhaust systems

[MonaroSS]

Originally Posted by Smaart Aas Saabr

2-stroke diesels just put a honking big supercharger (eg the "6-71 blower" on all those musclecars, well this is the supercharger off a Detroit Diesel 71-series engine) and that worked well.

Add in digital variable valve actuation and you don't even need the supercharger, but can use a more efficient turbocharger instead for scavenging.

The engine starts up and idles as a 4-stroke and as power is demanded, and after the turbo spins up, converts seemlessly to a 2-stroke...

[chinamonty]

Originally Posted by khooper

I hope IC engines have a future....after all, what are we going to do with all that oil if they don't? Oil is a resource meant to be used, like any other resource. Preferably responsibly
__________________________________
tips:always check the exhaust systems

I am sure that if you ask nicely someone will use it for power stations - start with China

[Smaart Aas Saabr]

not really

there is too much other things for oil... plastics... etc

[AMERICA 123]

Originally Posted by MonaroSS

Add in digital variable valve actuation and you don't even need the supercharger, but can use a more efficient turbocharger instead for scavenging.

The engine starts up and idles as a 4-stroke and as power is demanded, and after the turbo spins up, converts seemlessly to a 2-stroke...

Yes .....

And then you get rid of the intake poppet valve or other and replace with high pressure ' air injection ' after you've taken a pass thru your pre intake nitrogen reducer.

Meanwhile you continue to play with the fuel and some things related and some things more indirectly so.

[Wolfman01]

Originally Posted by Smaart Aas Saabr

Poppet valve 2-strokes (especially diesels) have been around for some time. Basically it works exactly as you say

When you use direct injection with a 2 stroke, you can scavenge with pure air, thus run too much air and get good scavenging, then close valves and inject fuel. This basically solves the big 2-stroke problem where you shoot some air + fuel, and half of the exhaust gets pushed out, with half of the fuel

Since diesels are all direct-injection or similar, the 2-stroke diesels just put a honking big supercharger (eg the "6-71 blower" on all those musclecars, well this is the supercharger off a Detroit Diesel 71-series engine) and that worked well.

Poppet valves also mean you can have a open crankcase w/oilpan, so you would just change oil like a 4-stroke with neat gasoline (or diesel) fuel

Thing is half the greatness of 2stroke is you can forget the valves...

The down side is that the old Detroits slobbered oil out the intake ports, ran away (from burning that same oil) and would sometimes even run backwards if it failed to start correctly, but got kicked backwards hard enough to fire the other way.

The poppet valves on the 2 stroke detroits and other 2 stroke diesel engines were only for exhaust. You checked the oil at every stop to refill the fuel tanks.

[Smaart Aas Saabr]

Oh yeah old Detroits, they were always covered in oil and ate oil and oil oil oil

That said they were the only thing that offered any kind of reasonable power density for a road vehicle... everything else the engine was so damn heavy it couldn't move.

[Michael_S]

Originally Posted by Smaart Aas Saabr

Poppet valve 2-strokes (especially diesels) have been around for some time. Basically it works exactly as you say

When you use direct injection with a 2 stroke, you can scavenge with pure air, thus run too much air and get good scavenging, then close valves and inject fuel. This basically solves the big 2-stroke problem where you shoot some air + fuel, and half of the exhaust gets pushed out, with half of the fuel

Since diesels are all direct-injection or similar, the 2-stroke diesels just put a honking big supercharger (eg the "6-71 blower" on all those musclecars, well this is the supercharger off a Detroit Diesel 71-series engine) and that worked well.

Poppet valves also mean you can have a open crankcase w/oilpan, so you would just change oil like a 4-stroke with neat gasoline (or diesel) fuel

Thing is half the greatness of 2stroke is you can forget the valves...

3 things:
1. Thank you very much for the info, I had no idea it was possible to have a 2 stroke engine that didn't send half its fuel out the exhaust.
2. Where do you learn things like this? I am always curious about automotive engineering and would like to learn more.
3. Do you think this kind of engine design would make sense in regular sedans, like a 2 stroke turbocharged or supercharged direct injection gasoline engine?

[Wolfman01]

Originally Posted by Smaart Aas Saabr

Oh yeah old Detroits, they were always covered in oil and ate oil and oil oil oil

That said they were the only thing that offered any kind of reasonable power density for a road vehicle... everything else the engine was so damn heavy it couldn't move.

I never drove an old two stroke detroit personally, but every old time truck driver I would talk to pretty much hated them. They had to be run up against their governors all the time to pull any grades. They were a rapidly dying animal in on highway use when I was driving. One thing that I will say about 'em is, that they sounded bad ass being wound up through the gears.

[Wolfman01]

Originally Posted by Michael_S

3 things:
1. Thank you very much for the info, I had no idea it was possible to have a 2 stroke engine that didn't send half its fuel out the exhaust.
2. Where do you learn things like this? I am always curious about automotive engineering and would like to learn more.
3. Do you think this kind of engine design would make sense in regular sedans, like a 2 stroke turbocharged or supercharged direct injection gasoline engine?

I don't know where Smart Ass Sabr gets his info, but I've gotten much of mine through curiosity, and simply reading up on the material. Type in 2-stroke diesel engine in Google, and you'll be reading for just about forever.

As for use in automotive applications, I don't personally see a future. The old detroits already mentioned were extremely thirsty, and used tremendous quantities of oil. Much of the same problems exist in any current interpretation of the poppet valve two stroke engine that existed then. Intake ports make controlling oil consumption extremely problematic, and this creates emissions problems.