Honda Power Unit Hardware & Software

[PlatinumZealot]

Wow, sad to say this but then they are in dreamland. Usually Honda is up there with Tech development but it seems to be missing in action now days.

Most countries would have banned ICE by then. If they need to do something its all electric now.
Hybrid tech at least Plug in might be useful for the next couple of years and that is it, it will be the end of the line.

Your theory is not realistic. I see you are being tricked by all the EV marketing!! Ha.
Going by observations of all sectors and some reading, I can say ICE technologies for passenger cars will be around for decades more, yet. Maybe even longer.

I know it may seem splitting hair, but are any countries banning ICE's?
There are several who have said they will not allow production of ICE only vehicles, but don't recall any ban on ICE, which would include gas (not gasoline, but the likes of hydrogen) Bio fuels with ultra low emission etc.

Saying they will ban production / importation or whatever is one thing...

Realistaclly many things will have to be in place and we just have to wait and see. For examole plastic grocery bags are banned in some countries but plastic garbage bags and others are still used in those places becuase they have no reasonable alternative. Imagine a guy who can only afford a used vehicle in a certain price range, how will he be able to buy an EV?much less one with a fifteen year old battery? So many little things will have to be sorted befor the death knell is rung. Other forces also exist too. Giants like Aramco are doing everything they can to keep petrol sipping vehicles alive forever. This stuff is bigger than me.. But from a layman point of view I see passenger car ICE being around long after I leave this dimension.

[gruntguru]

Whether the pre-chamber has orifices that are radial or not (as shown in the image above to generate swirl in the pre-chamber) doesn't alter the discussion of how F1 has succeded in implementing TJI without 2 injectors/cyl.

I am still of the opinion that the pre-chamber contains the spark plug but no injector and that the injector is mounted at the edge of the chamber spraying towards the centre. Richer AFR in the pre-chamber is achieved by timing the injection pulses - early pulses (near BDC) produce lean mix in the pre-chamber and late pulses (near TDC compression when flow into the pre-chamber is highest) produce rich mixture.

[Rodak]

It looks like the rotating pre-chamber setup requires two fuel injectors, one for a rich mixture in the pre-chamber and the other for the lean combustion mixture. F1 only allows one injector....

Inject twice from single injector?

And how would you make that work? Seems like there might be some timing issues. How long does the injector operate to introduce a cylinder charge and when does it operate re piston position?

[63l8qrrfy6]

It looks like the rotating pre-chamber setup requires two fuel injectors, one for a rich mixture in the pre-chamber and the other for the lean combustion mixture. F1 only allows one injector....

Inject twice from single injector?

And how would you make that work? Seems like there might be some timing issues. How long does the injector operate to introduce a cylinder charge and when does it operate re piston position?

Normal road going car engines operate with multiple injection events per cycle, it's a non-issue.

Look up GDI split injection.

[Rodak]

At 12,000 rpm a cylinder is firing 100 times/sec. I'm curious how a rich fuel charge could be injected so that it would enter a pre-chamber and provide the necessary jet features and when that would be done during the cycle. It would seem to require some very accurate timing and flow rates to provide a charge while also injecting a lean fuel mixture for the combustion process. The injection nozzle direction would be critical so that a rich mixture entered the pre-chamber, forced in during the compression stroke. I don't know what timing advance F1 engines typically use, but it would probably be somewhere in the 20° BTDC range ± I would guess. Please correct if I'm way off.

[PlatinumZealot]

The fuel injection event happens very early. A little after the exhaust valve closes on the intake stroke. That is why the direct injection pistons have that sculpted shape. So you can do multiple injections to get the desired combustion.

Honda has shown a few generic pre-chamber diagrams but we know they wont show the real thing anytime soon.

[godlameroso]

At 12,000 rpm a cylinder is firing 100 times/sec. I'm curious how a rich fuel charge could be injected so that it would enter a pre-chamber and provide the necessary jet features and when that would be done during the cycle. It would seem to require some very accurate timing and flow rates to provide a charge while also injecting a lean fuel mixture for the combustion process. The injection nozzle direction would be critical so that a rich mixture entered the pre-chamber, forced in during the compression stroke. I don't know what timing advance F1 engines typically use, but it would probably be somewhere in the 20° BTDC range ± I would guess. Please correct if I'm way off.

The injected mixture becomes rich because it is in a smaller volume. A deflated balloon has atmospheric pressure inside it, so if you pinch the end, the remaining air somewhat inflates the balloon after the part you pinched.

A better analogy, imagine there's 100 really really mean dogs, these dogs will tear you to shreds, just attack you if they see you. You can take 1 or 2 dogs, but 3 or more becomes dangerous. If those 100 dogs are spread out over an area the size of Paris(lean charge), what are the chances you run into 3 or more dogs? What if those 100 dogs are in 10 city blocks(piston at TDC) and 15 of them live in your building(the prechamber), what are the odds you run into 3 or more then?

This goes back to the discussion of cylinder filling. The intake cycle is really 1.5 strokes. After the exhaust valves have opened and the exhaust pulse has blown down from the cylinder, the cylinder goes up, and once at TDC the exhaust valves are closed and exhaust gases mostly pushed out. The piston begins to accelerate downward, and the air that's stored in the plenum shoots down the intake ports over the intake valves, aided by the large mass of high pressure air in the plennum and the partial vacuum created by the piston down motion. The motion of this air as it fills the cylinder has huge influence in how the fuel is mixed in the combustion chamber.

Particularly due to the fact direct injection is used, a big problem is fuel wetting, there's little time for the fuel to vaporize into it's combustible state. Turbulence aids fuel mixing, but turbulence can lead to flow reversion which robs power/flow velocity. At the end of the day these are still air pumps, so getting the air in and out of the engine efficiently is critical for power.

Depending on your intake port geometry, the valve shape, the piston crown, and the shape of the chamber, and valve timing you can make air do different things at different parts of the intake stroke, so if you want, you can induce tumble and turbulence during the initial filling phase, slowing intake charge down, firing the plug, and inducing swirl on the compression phase, which sets up the final cylinder injection. The change from tumble to swirl mid intake/compression stroke, backs up the intake charge, and then pulls it in at the last moment, so that the cylinder is fully filled at TDC and the swirl motion helps vaporize the fuel as the swirl motion reduces wall wetting.

The regulations allow as many injection pulses as you want as long as you stay within the 100kg/h rule @10,500rpm, you are also allowed 5 spark ignitions per engine cycle.

[etusch]

Whether the pre-chamber has orifices that are radial or not (as shown in the image above to generate swirl in the pre-chamber) doesn't alter the discussion of how F1 has succeded in implementing TJI without 2 injectors/cyl.

I am still of the opinion that the pre-chamber contains the spark plug but no injector and that the injector is mounted at the edge of the chamber spraying towards the centre. Richer AFR in the pre-chamber is achieved by timing the injection pulses - early pulses (near BDC) produce lean mix in the pre-chamber and late pulses (near TDC compression when flow into the pre-chamber is highest) produce rich mixture.

you say that it is passive prechamber.
my theory is injector and prechamber is side by side and when injector injected at least one orrifice of it works direct into prechamber. And others or other one works to main chamber

[PlatinumZealot]

Whether the pre-chamber has orifices that are radial or not (as shown in the image above to generate swirl in the pre-chamber) doesn't alter the discussion of how F1 has succeded in implementing TJI without 2 injectors/cyl.

I am still of the opinion that the pre-chamber contains the spark plug but no injector and that the injector is mounted at the edge of the chamber spraying towards the centre. Richer AFR in the pre-chamber is achieved by timing the injection pulses - early pulses (near BDC) produce lean mix in the pre-chamber and late pulses (near TDC compression when flow into the pre-chamber is highest) produce rich mixture.

So... How much is known about that sort of stratified concentration? And at the small time scale it must happen in?

Ooh! You rumbled some ponderings in my mind.

I am thinking of how a nozzle is usually works best at a certain flow range. Some nozzles are basically like normal openings if the flow rate through them is too low. The don't work until the flow is appreciable.

Now... As you say, it must be a passive prechamber.
The ideal location may be the center of the cylinder, but that does not preclude it from being off-set. We can confirm that the injectors are side mounted and are on the exhaust side of the cylinders. But the chamber can also still be in the centre. Or the side. Depending on how it is fed by the injectors.
The spark plugs, though we have not seen them or their wiring? (can't confirm if those are just sensor wires?) likely are in a conventional location. Bringing into the picture now, the position of the valves, this gives us very few options for how the pre-chamber is located and how the inejctor feeds it..

I gonna sketch something... But I agree that the timing of the fuel can determine the stratification in the pre-chamber versus the rest of the combustion chamber.

[godlameroso]

Whether the pre-chamber has orifices that are radial or not (as shown in the image above to generate swirl in the pre-chamber) doesn't alter the discussion of how F1 has succeded in implementing TJI without 2 injectors/cyl.

I am still of the opinion that the pre-chamber contains the spark plug but no injector and that the injector is mounted at the edge of the chamber spraying towards the centre. Richer AFR in the pre-chamber is achieved by timing the injection pulses - early pulses (near BDC) produce lean mix in the pre-chamber and late pulses (near TDC compression when flow into the pre-chamber is highest) produce rich mixture.

So... How much is known about that sort of stratified concentration? And at the small time scale it must happen in?

Ooh! You rumbled some ponderings in my mind.

I am thinking of how a nozzle is usually works best at a certain flow range. Some nozzles are basically like normal openings if the flow rate through them is too low. The don't work until the flow is appreciable.

Now... As you say, it must be a passive prechamber.
The ideal location may be the center of the cylinder, but that does not preclude it from being off-set. We can confirm that the injectors are side mounted and are on the exhaust side of the cylinders. But the chamber can also still be in the centre. Or the side. Depending on how it is fed by the injectors.
The spark plugs, though we have not seen them or their wiring? (can't confirm if those are just sensor wires?) likely are in a conventional location. Bringing into the picture now, the position of the valves, this gives us very few options for how the pre-chamber is located and how the inejctor feeds it..

I gonna sketch something... But I agree that the timing of the fuel can determine the stratification in the pre-chamber versus the rest of the combustion chamber.

Spark plug location affects airflow motion, as that is where the flame kernel propagates from. Old school 2 valve heads are much more susceptible to chamber shape and plug location than 4 valve heads.

The paper I posted with the swirly spark plug could be used to aid the transition from tumble to swirl in the CC so it behaves like old school 2 valve heads.

As I said the intake stroke is really 1.5 strokes, the air flowing into the cylinder on the suction phase behaves as a fluid because, it's a fluid, and one of the properties of fluid is inertia. Water is also a fluid, and as Bruce Lee said, water can drip, flow, or crash, and so can air. The air going into the cylinder is .75 of a stroke, and the air staying in that cylinder as the piston compresses is the other .75 of a stroke, both overlap with the blow and squish part of the suck squish bang blow cycle.

It really should be called suck fill squish bang blow fill, if stratifying the charge is goal, you must be mindful of this.

If natural egr can be used to stratify fuel charge in stationary turbines why not ICE's? Thanks for that Mr.Flap.

[PlatinumZealot]

The Kernel near the spark plug does not apply the same in jet ignition. Remember now, that the jets are igniting the bigger mixture. That means the spark plug can be in a different position or even location than the norm if required.

[godlameroso]

The Kernel near the spark plug does not apply the same in jet ignition. Remember now, that the jets are igniting the bigger mixture. That means the spark plug can be in a different position or even location than the norm if required.

No way dude. The kernel near the spark plug always follows the same rules. It doesn't just start behaving differently because PZ needs to win on the interwebz. When a sparky goes off, it always makes that pop noise. That's the sound of air clapping with one hand. The sparky is the prime mover of combustion in a spark ignition engine whether it has a pre chamber or not.

That spark pushes air in a certain direction, it has to, or it wouldn't make that popping noise.

[PlatinumZealot]

The Kernel near the spark plug does not apply the same in jet ignition. Remember now, that the jets are igniting the bigger mixture. That means the spark plug can be in a different position or even location than the norm if required.

No way dude. The kernel near the spark plug always follows the same rules. It doesn't just start behaving differently because PZ needs to win on the interwebz. When a sparky goes off, it always makes that pop noise. That's the sound of air clapping with one hand. The sparky is the prime mover of combustion in a spark ignition engine whether it has a pre chamber or not.

That spark pushes air in a certain direction, it has to, or it wouldn't make that popping noise.

An ill informed answer.

We are both discussing TJI right? The effets surrounding the kernel does not affect the combustion of the mixture in the main chamber the same way as in an engine without TJI. That is a fact.
The kernel has an important influence in especially lean mixtures, but in the pre-chamber the mixture is not lean at all. But anyway, once that body of fuel is ignited the main ignition is carried out by the jets created from there.

On the other Plasma ignition is a type of ignition where the kernel characteristic is an extremely important differentiator and what is used to allow very lean combution. In TJI we are not as extreme becsuse the fuel is not lean in the pre-chamber.

[godlameroso]

A spark from a spark plug discharge is plasma. The spark is created by the difference in charge from the positively charged electrode and the surrounding ground. At 40,000v+ the air at the spark gap is stripped of electrons and creates a plasma along with oxygen radicals that starts the combustion chain reaction. Banning plasma ignition while requiring spark plugs is a ridiculous regulation if you ask me.

Create a spark plug with a cone shaped grounding strap, boom plasma spark plug, now you can direct the flame kernel. Even if the plug is inside the pre-chamber, the plug design and electric discharge can affect how the flames propagate from the jets of the pre-chamber.

[godlameroso]

Consider also what the rotating pre-chamber is meant to solve, if the pre-chamber is relatively rich, then it stands to reason that if you can't purge the mixture from the pre-chamber you will get unburned hydrocarbons to accumulate in the pre-chamber which would affect reliability of the engine. It's very easy for carbon deposits to obstruct the pre-chamber jet orifices if you can't fully purge the pre-chamber mixture.

Lot easier to do maintenance on these power units if the sparky has the pre-chamber attached to it, because then you don't have to pull the head apart to remove and clean it. Just toss on a new sparky.