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Engine design idea
- Thread starter graver555
- Start date
I think that in order to (potentially) improve the ignition system with the idea you have presented you would generate a considerable amount of new problems which need to be overcome.
-How will you circulate coolant throughout the block if you isolate and divide the cylinders with an insulating material?
-How do you control spark arc points to prevent scarring of cylinder walls (add arc points to piston center and block contact point?)
-How do you prevent transfer of electrical energy through lubricating fluids which coat the underside of the piston?
-Many modern blocks have silicon based sleeve inserts to reduce wear, the insulating properties of which may disrupt electrical transfer.
-How do you direct current into the rotating piston assembly, contact based, brushes, etc?
-All piston rings, crank, etc will now need to be insulators to prevent incidental transfer and voltage loss which would diminish spark potency.
Instead of using the engine assembly as the anode/cathode perhaps include an anode/cathode array across the cylinder diameter in the compressed range above TDC. This too encounters the issue of insulating the engine and removing it from the grounding loop of the system. Not to mention the considerable increase in voltage required to arc across a greater distance. And how to access the nodes for service/repair/replacement? In a boxster style flat engine not so bad, but a V6, much harder.
The initial goal was to ignite more fuel, but in reality, fuel ignition is impeded the most by poor air/fuel ratio. Most modern engines, especially after a good tune of the fueling map burn very efficiently even with modest factory ignition systems. A minor upgrade to the existing ignition system, and a good tune will probably generate a more efficient combustion cycle than a lightning storm in the cylinder head.
So in summary, very neat idea, but I think you will find the technical limitations to be more trouble than they are worth. But depending on your available time/budget it could be a great unique creation.
If you're dead set on tinkering and want to find a way to improve performance instead see if you can develop some sort of cylinder flushing gas injection system. Much of the engine's potential is lost due to combustion remnants remaining in the cylinder after the exhaust cycle. If you could time an injection of clean air, oxygen, nitrous, etc such that it removes the lingering exhaust gases and pre-charges the cylinder with fresh air prior to the induction cycle you could increase the combustion cycle efficiency and fuel economy. This would require far less alterations to the engine block and components, and could be achieved using a relatively simple pneumatic system (the controls system would be a b**** however). Plus, lets say your gas source runs out or your system fails, when it shuts down you just have a standard engine, no harm no foul. Several newer vehicles use DIG systems which could be a good template to follow for this system.
-How will you circulate coolant throughout the block if you isolate and divide the cylinders with an insulating material?
-How do you control spark arc points to prevent scarring of cylinder walls (add arc points to piston center and block contact point?)
-How do you prevent transfer of electrical energy through lubricating fluids which coat the underside of the piston?
-Many modern blocks have silicon based sleeve inserts to reduce wear, the insulating properties of which may disrupt electrical transfer.
-How do you direct current into the rotating piston assembly, contact based, brushes, etc?
-All piston rings, crank, etc will now need to be insulators to prevent incidental transfer and voltage loss which would diminish spark potency.
Instead of using the engine assembly as the anode/cathode perhaps include an anode/cathode array across the cylinder diameter in the compressed range above TDC. This too encounters the issue of insulating the engine and removing it from the grounding loop of the system. Not to mention the considerable increase in voltage required to arc across a greater distance. And how to access the nodes for service/repair/replacement? In a boxster style flat engine not so bad, but a V6, much harder.
The initial goal was to ignite more fuel, but in reality, fuel ignition is impeded the most by poor air/fuel ratio. Most modern engines, especially after a good tune of the fueling map burn very efficiently even with modest factory ignition systems. A minor upgrade to the existing ignition system, and a good tune will probably generate a more efficient combustion cycle than a lightning storm in the cylinder head.
So in summary, very neat idea, but I think you will find the technical limitations to be more trouble than they are worth. But depending on your available time/budget it could be a great unique creation.
If you're dead set on tinkering and want to find a way to improve performance instead see if you can develop some sort of cylinder flushing gas injection system. Much of the engine's potential is lost due to combustion remnants remaining in the cylinder after the exhaust cycle. If you could time an injection of clean air, oxygen, nitrous, etc such that it removes the lingering exhaust gases and pre-charges the cylinder with fresh air prior to the induction cycle you could increase the combustion cycle efficiency and fuel economy. This would require far less alterations to the engine block and components, and could be achieved using a relatively simple pneumatic system (the controls system would be a b**** however). Plus, lets say your gas source runs out or your system fails, when it shuts down you just have a standard engine, no harm no foul. Several newer vehicles use DIG systems which could be a good template to follow for this system.
It is an interesting idea, but except for the part about using an arc across the pistons - which, as has been pointed out, won't work because of the distance between them - you're about 110 years too late. Opposed piston engines have been around for a long, long time. Some US Navy submarines use them as auxiliary power plants, in fact. I remember some very big ones, made by Fairbanks-Morse, in the base power plant at Howard AFB in Panama, back in the '70s. They were super-charged 2-stroke Diesels, with pistons about the size of garbage cans. Made an ungodly noise, too.
Flame spread during combustion is a very highly studied area of internal combustion power generation and I'm afraid the method you are asking about would be not much different that what is known as pre ignition. In a conventional engine the flame spread is controlled and works best from the top down to get en efficient burn. If the entire cylinder/piston became the ignition source, the end result would be burning the fuel on top of the piston at the same time or before igniting the fuel in the top of the jug which would prevent the piston from completing it's full travel range in the stroke. As ignition is occurring, the piston continues to advance into the flame front so it is actually a few degrees further into the compression stroke before the charge adjacent to the piston is ignited.
In short, if you ignited the entire charge at once you would need to advance the timing to, or within a few degrees of TDC to prevent pre ignition. If you advance the timing that far you will get combustion from compression long before you reached the position were you would use a spark to ignite the charge.
Here's the other thing, every gram added to the reciprocating mass, makes it increasingly difficult to balance and control that mass. Vibration is the killer of recip engines and the more weight you are moving the harder it is to control that vibration. Not saying it couldn't be done, but it would really drive the price of production engines up to try to attach the ignition to the internal moving parts of the engine. The key to good engine design is as few moving parts as possible.
The ignition on my truck is totally electronic (no moving parts) unless you count the slug in the flywheel, and is highly efficient and tuneable.
In short, if you ignited the entire charge at once you would need to advance the timing to, or within a few degrees of TDC to prevent pre ignition. If you advance the timing that far you will get combustion from compression long before you reached the position were you would use a spark to ignite the charge.
Here's the other thing, every gram added to the reciprocating mass, makes it increasingly difficult to balance and control that mass. Vibration is the killer of recip engines and the more weight you are moving the harder it is to control that vibration. Not saying it couldn't be done, but it would really drive the price of production engines up to try to attach the ignition to the internal moving parts of the engine. The key to good engine design is as few moving parts as possible.
The ignition on my truck is totally electronic (no moving parts) unless you count the slug in the flywheel, and is highly efficient and tuneable.
I figured it wouldn't work, but then again it was very late at night when I thought of it. Thanks for all the replies
I figured it wouldn't work, but then again it was very late at night when I thought of it. Thanks for all the replies
That's ok, just yesterday I thought I invented the opposed engine
Gaolee
Official leathers tester and crash dummy
Two spark plugs is a whole lot lighter than two crankshafts and all gears necessary to attach them to one output shaft.
Interesting idea. I'll talk out my thoughts.
On the intake stroke, both pistons would be going outward. The intake valves would need to be in the middle and open. Then on the compression stroke, the intake valves would closed while the pistons press towards each other.
Then, at TDC (or somewhere before or after depending on timing), the spark would go off and ignite the compressed air/fuel mixture. Because it's not just a spark between a 1-ish mm gap but a much farther distance, it would cause a pretty fast burn. The power stroke would push the pistons apart. Then, the final stroke would push the exhaust gases out the exhaust valves.
A couple thoughts.
You have almost twice the rotating mass. Two cranks, two pistons and two connecting arms for each cylinder, etc. That's more weight and less power going to the wheels. Why have two pistons per cylinder? If you want a gigantic spark, why wouldn't you just connect one terminal to the spark plug spot and the other end to the piston?
Another issue I see is what if one piston is pushed more than the other piston on the power stroke? Is there a chain that synchronizes both cranks like a timing chain does for multiple cams to prevent that? That's more rotating weight to add to the engine.
You have this flat-8 design but in reverse, so now the cylinder head is in the middle rather than have two on the outside. I don't know if you would design one cylinder head to house both the intake and exhaust valves. This would cut down on weight. Or would you have one cylinder head on the top of the block for the intake and one on the bottom of the block for the exhaust. By separating them on opposite sides of the block, you allow the intake valve area to be larger and allow more air in. Same thing on the exhaust side. If you put them on the same side, you end up in the same situation with normal engines.
Overall, I don't like the idea of added mass in rotating parts. Because you still have a 4-stroke engine, so you'll need 8 pistons for 4 cylinders, 12 pistons for 6 cylinders and 16 pistons for 8 cylinders. It's like building a running shoe with lead weights in the soles.
It is an interesting idea, but except for the part about using an arc across the pistons - which, as has been pointed out, won't work because of the distance between them - you're about 110 years too late. Opposed piston engines have been around for a long, long time. Some US Navy submarines use them as auxiliary power plants, in fact. I remember some very big ones, made by Fairbanks-Morse, in the base power plant at Howard AFB in Panama, back in the '70s. They were super-charged 2-stroke Diesels, with pistons about the size of garbage cans. Made an ungodly noise, too.
Some of those were deltic engines. Three cranks and all opposed piston. Used in English patrol boats during WWII. Lots of monkey motion going on.
I also had a weird engine idea.
What if you took a large diesel engine for a bus/train/boat/large vehicle and then made the cylinder head, engine block, and exhaust manifold (and or turbo) as the heating elements for a steam boiler. The boiler would act just like a steam locomotive engine. As it heats up the water, the steam pressure would push pistons. So, the engine would still burn diesel, but the heat would be captured and reused to generate steam power. There would be a second set of pistons driven by steam power that would connect to the same driveshaft with a clutch. When enough steam is generated to operate the pistons, the clutch would engage and assist the diesel motor.
Then, as the steam power provides more torque, the diesel engine doesn't have to operate at the same RPMs so less fuel is needed.
This wouldn't work for personal cars and pick-up trucks because the boiler would just be too large and heavy and water management wouldn't make it feasible.
What if you took a large diesel engine for a bus/train/boat/large vehicle and then made the cylinder head, engine block, and exhaust manifold (and or turbo) as the heating elements for a steam boiler. The boiler would act just like a steam locomotive engine. As it heats up the water, the steam pressure would push pistons. So, the engine would still burn diesel, but the heat would be captured and reused to generate steam power. There would be a second set of pistons driven by steam power that would connect to the same driveshaft with a clutch. When enough steam is generated to operate the pistons, the clutch would engage and assist the diesel motor.
Then, as the steam power provides more torque, the diesel engine doesn't have to operate at the same RPMs so less fuel is needed.
This wouldn't work for personal cars and pick-up trucks because the boiler would just be too large and heavy and water management wouldn't make it feasible.
Carbon fiber is actually conductive (not all types though) which is why you shouldn't buy cheap CF welding hoods (it can be flammable as well IIRC). I can't imagine it working well for drivetrain gearing, although I am no expert.
Hi this motor has been invented and in ise for quite a while. It has it's purpose.
Also if I remember right it doesn't have any heads? It has headers going into it but the valve springs are replaced by slots that are closed off by the pistons themselves. Or mayby this was just with 2cycle diesel versions.
And then you have the 4 and 2 stroke opposed engine:
http://en.wikipedia.org/wiki/Two-_and_four-stroke_engines
http://en.wikipedia.org/wiki/Two-_and_four-stroke_engines
Oh, so the OP imagined a new engine that already existed without having seen it.
Well, he's a genius!
That is very difficult to wrap my head around properly. Is this a viable usable engine?
No. Not the space elevator. That kickstarter idea is trash. Now, the space escalator... oh yeah. That's the future.
