Improving the efficiency of the 4 stroke motor...?

[jjdugen]

Going to get a bit 'Teff' on you all. I've been looking at various methods of making more power from the 4 stroke engine and came up with this thought. Not found anything similar after a long search on the Google, but if its been tried before I'd like to know the outcome. At least its been published so I can claim ownership if BMW try to steal it!

The idea follows from the 2-strokes auxiliary ports found in most performance engines. There they have a 'blind' port in the barrel that adds a squirt of fuel during the combustion process. As far as I can tell, no-one has thought of putting just such an auxiliary port into a 4 strokes barrel.

1. Shows the piston on compression stroke, filling both cylinder and aux port with compressed mixture.
2. Shows piston at TDC the normal above piston mixture ready for combustion and the aux port covered / blanked by the piston skirt.
3. Shows the normal fuel combustion cycle.
4. Shows the aux port uncovered, the compressed mixture now combining with the spent but hot combustion gases, adding an extra combustion process, a double bang if you like.
5. Shows the normal exhaust stroke, poppet valve open.
6. Shows the rotary valve in the aux chamber open to purge the aux chamber of burnt gases.

Once the induction stroke occurs, aux chamber rotary valve closes to allow fresh mixture to fill the cylinder.

Anybody got the odd million or two spare for development costs?

Cheers.
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[MarJay]

I've seen a similar thing to this before... it was on an old episode of Top Gear IIRC.
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[Kris]

Suzuki do this with air using their PAIR system.
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[Aff]

[sickpup]

First of all rotary valves have the problem that they don't seal very well in the presence of high temperatures, this is why engines still have the valve arrangement that they have.

Your idea has been used for decades by the use of accelerator pump carbs and now by pressurised fuel injectors, what advantages does your system have over those considering it is more complex and more prone to raising hydrocarbons in the exhaust gasses?

As you are injecting an additional measure of fuel why do you think it makes the engine more efficient?

The engine you have designed is inherently inefficient as the fuel and exhaust inlets have an almost 90degree bend in them. Inclining the engine so as to use a down draught design would mean you can increase the velocity of the inlet charge especially at high revs meaning you could achieve volumetric efficiencies of over 100%.

[P.]

[sickpup]

Psst Paddy, what do you thing a Turbo or Supercharger does?

[jjdugen]

Hi,
First off, as mentioned, PAIR type systems are just a way of putting fresh air into the exhaust gases to 'clean them up' a bit.

Second, treat the diagrams as an explanation, not the finished article. Down draughting the carbs / injectors is a given, as would be all the latest multi valve and high compression ratio tricks.

I take the point about emissions, but this will be a low compression secondary burn, so won't generate the nasty stuff of a very high comp burn.

My 'logic' on this was that most of the energy from the initial ignition dissipates over the first eighth of the pistons down-stroke, this would add an extra bit of gas expansion beyond that.
Only direct injection would allow for high pressure filling of the cylinder, and is high quality engineering.
I do take the point of rotary valve sealing, it might not actually need a vent to atmosphere, that will need investigating with the million or two development money!
Unlike turbos that need sufficient engine speed to work, or superchargers that are a mechanical drain on power produced, this is neither rev dependent nor requires the complexity of mechanical devices.
____________________
The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

[sickpup]

[P.]

[_Iain_]

[P.]

Would love some deadly TL. Add le turbo to a V twin though, doesn't look fun.

Varadero with chinese turbo and 5hp nos though. Sort me out Iain.

[_Iain_]

[Kickstart]

Hi

Not sure how much it would help.

The timing should already be set up so that the most useful amount of burning mixture occurs at the best time to turn the crank. If the mixture is burning too soon and too fast then just use more retarded ignition and a shorter stroke.

To me it looks like it is just going to suddenly lower the cylinder pressure as the port is uncovered at the time you want the pressure to be fairly high, pushing down on the piston and turning the crank, and only gaining a small amount back when that low pressure mixture does burn.

While the extra exhaust port might help, not sure how much. Exhaust valves and ports are treated as less important than intakes as there is little to gain there.

All the best

Keith
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[lihp]

How do you propose to open and close the rotary valve?
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[Walloper]

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[Nobby the Bastard]

Surely the pressure of the 'bang' would push the unburnt mixture into the area where the secondary valve is, preventing any extra boom out where the piston is and actually lower the power you achieve...
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[Walloper]

Here is the bottom line on it.

Invention is all good and well. Application is another thing.
As Sickpup has clearly illustrated, sealing would be an issue.

Most of what can be done to squeeze the energy out of petrol has been done. As far as burning it goes.

If anyone wants to 'have a go' at improving efficiency then they need look at reducing thermal and frictional losses which make up about 60% of energy waste/inefficiency.

That's where the money is.
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[lihp]

If this was a legit way of increasing efficiency they would be doing it with F1 and MotoGP engines where they have the worlds best engineers, with the worlds leading technology and are restricted on fuel level.

If it was worthwhile it would have probably been done.
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[1cyl]

I admire your dedication OP.

But I'd advise channeling your mental invention energy into electric motors or more specifically the battery's. If you can nail the lightweight, huge power, long lasting, fast charging, cheap costing dilemma, then you'll do us all a favour.
The internal combustion engine is gonna have to go before this century is out, otherwise, we fail.
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[Walloper]

[lihp]

[jjdugen]

Battery powered vehicles are the same dead end that steam engined cars were. Electric vehicles may be a future solution, but only when all roads have induction loops under the surface. I still think Hydrogen On Demand (HOD, great acronym), engines will prove the more usable solution, once I can find the right frequency / voltage to excite and crack water molecules, (I've been here before and got shot down in flames).

IF I could find any reference to this system being tried and any results, I would be studying them, but I have trawled t' interweb and can find no mention of anything like this system. As I have said, if anyone has found any relevant data that applies I would be glad to see it.
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The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

[lihp]

Hyundai currently sell a hydrogen car
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[Tarmacsurfer]