Honda Power Unit Hardware & Software

[glenntws]

Ok. Do you think that wazari gave us ALL of the firing orders that the engine uses for various reasons? Whether it is warm up, cool down, or some other strange reasons?

While I don't think, that every firing order is used, your idea is very good.

In the video where jenson pulled out of the garage the engine seemed to change from that weird tone to a more regular one.

Could it be an on-the-fly change in firing order?

Yes I am very sure that Honda uses 2-3 cylinder work during low load or idle and under more than 35%-40% full cylinder power.

On-the-fly change is possible. Remeber the lovely Sound the MP4-30/31 made when coming out of the corner, this sound could only be created by cylinder shutoff and the switching back.

And just being a little crazy here: The other firing orders Wazari listed with the "dead cylinders" the ones having a a complete of 1080 degrees. Could these firing orders be a form of cylinder deactivation? Instead of one ingition event in 720 degrees. It is instead two ignition events in 2160 degrees. In effect one vacuous or missing power stroke in every three normal cycles.

This could really be something real. Maybe my knowledge from my engine project could help here. Using a manifested list of working cylinders under shutoff condition for high Performance engines isn't favoured because of highly unequal wear and warmup. Using all cylinders, but create a weird order with very wide intervals has the same effect but has the Advantage of equal wear. And: Even though the "big-bang" idea isn't very useful in a F1 engine, having some bigger torque spikes could improve out-of-corner speed.

Let's just think about that shortly: The sound of the soundfile fits to 1-2-3-4-5-6 with 1,3,6 shutted of. This could maybe be something like a "warmup" or something like that mode. When thinking about the other orders with the same crankshaft as 1-2-3-4-5-6 or 1-4-2-5-3-6(they're the same), this would create the following scenarios:

1-4-5-6-3-2: 1 - 450° - 4 - 120° - 5 - 120° - 6 - 270° - 3 - 600° - 2 - 600° - 1
This is pretty useless, this kind of power delivery wouldn't work well. The exhaust gas flow to the turbine would be very pulse-like. While this isn't good for efficiency under high loads, it would work out ok for lower loads and could maybe work out for a bit higher turbine Speed, but I don't think so.

1-5-3-6-2-4: 1 - 670° - 5 - 390° - 3 - 450° - 6 - 150° - 2 - 330° - 4 - 270° - 1
This method could resemble a 2 cylinder engine. Definetly possible...
The flow to the exhaust turbine would be more efficient. Maybe the "big-bang" on 6-2 could help Keep the turbine Spinning on higher rpms.

This could be used under braking maybe?
Or lift and coast?
Or for exhaust gas recirculation(the exhaust from the other active cylinders would easily flow into the "dead" ones?

Under braking is like low loads, the Keep the turbine under rotating to reduce power spent on MGU-H for spooling up.
Lift and coast would be same.
Exhaust gas recirculation doesn't work well this way I think.

[wuzak]

Ok. Do you think that wazari gave us ALL of the firing orders that the engine uses for various reasons? Whether it is warm up, cool down, or some other strange reasons?

Could it be an on-the-fly change in firing order?

Surely the firing order is fixed by the crankshaft layout, the cylinder layout (ie 90° V6) and the camshaft timing, since that cannot be variable as per the rules?

[glenntws]

Ok. Do you think that wazari gave us ALL of the firing orders that the engine uses for various reasons? Whether it is warm up, cool down, or some other strange reasons?

Could it be an on-the-fly change in firing order?

Surely the firing order is fixed by the crankshaft layout, the cylinder layout (ie 90° V6) and the camshaft timing, since that cannot be variable as per the rules?

That's right, but you can leave out ignitions and jump over to the next you want, which has the effect of cylinder shutoff.

[roon]

Another idea to chew on, satisfying Wazari's hints, namely:

-shorter crankshaft
-unique connecting rod journal design
-unique sound

How about a V6 with conjoined pistons, a single throw crank, and fork-and-blade connecting rods? I've alluded to this in some previous posts but thought I'd do a quick sketch. Each bank has the required three cylinders, but each joined to the others at their base to form one rigid part. This then is connected to the single-throw crankshaft with fork-and-blade connecting rods in an expected manner.

Speculated advantages:

-A shorter crank accommodates coaxial MGU-K installation fore or aft of the crankshaft
-Per-bank firing provides a larger, hotter exhaust pulse to the turbine

The rulebook stipulates that the crankshaft must have three connecting rod journals, but does not specify the number of throws. By using a stepped journal design you can line up three journals upon one throw. By using fork-and-blade conrods we can create a symmetrically-stepped journal. This coincidentally offers the advantage of symmetrical loading of the three journals.

We end up with something like a V-twin producing the following firing order:

[1, 2, 3] - [4, 5, 6]

Which is a firing order that Wazari recently suggested. Although I added the brackets. Since the entire bank will be on blowdown simultaneously, this might facilitate a return to a compact log manifold.

A 1+3, 5, 2, 4+6 order would also be possible. Or similar (alternating inner cylinder & with outer two cylinders, per bank).

I've been puzzled by Wazari's suggestions, specifically how to create a short crank that was short enough while satisfying a three journal-requirement. After some consideration this is what I arrived at. Illustration follows.



Edit- updated drawing.

[wuzak]

Excellent drawing an out-of-the-box thinking, but the limit of the length of the block, and this the crankshaft, is the bore spacing. Assuming that the bore spacing is already at a minimum, the only way to shorten the crank is to remove the left to right bank offset. Which your system does, but so does just using fork and blade rods on a conventional crank.

Glenn already provided the timing for 1-2-3-4-5-6 firing order.

With 1-2-3-4-5-6, the ignition timing would be:
1 - 120° - 2 - 120° - 3 - 210° - 4 - 120° - 5 - 120° - 6 - 30° - 1

[glenntws]

Another idea to chew on, satisfying Wazari's hints, namely:

-shorter crankshaft
-unique connecting rod journal design
-unique sound

How about a V6 with conjoined pistons, a single throw crank, and fork-and-blade connecting rods? I've alluded to this in some previous posts but thought I'd do a quick sketch. Each bank has the required three cylinders, but each joined to the others at their base to form one rigid part. This then is connected to the single-throw crankshaft with fork-and-blade connecting rods in an expected manner.

Speculated advantages:

-A shorter crank accommodates coaxial MGU-K installation fore or aft of the crankshaft
-Per-bank firing provides a larger, hotter exhaust pulse to the turbine

The rulebook stipulates that the crankshaft must have three connecting rod journals, but does not specify the number of throws. By using a stepped journal design you can line up three journals upon one throw. By using fork-and-blade conrods we can create a symmetrically-stepped journal. This coincidentally offers the advantage of symmetrical loading of the three journals.

We end up with something like a V-twin producing the following firing order:

[1, 2, 3] - [4, 5, 6]

Which is a firing order that Wazari recently suggested. Although I added the brackets.

I've been puzzled by Wazari's suggestions, specifically how to create a short crank that was short enough while satisfying a three journal-requirement. After some consideration this is what I arrived at. Illustration follows.

https://i.imgur.com/ZU9r3bqh.jpg

Basically a possible idea and a good sketch, but: the rules talk about 3 crankpins so a least you would need 2 "dummy" crankpins. Next, a system like that would be highly unstable. You get a very massive force on the outer pistons and the rod, which would kill this assembly pretty fast I think.

The biggest problem however is the space you need for this to work. The radial space of the crankcase would need to be increased by a big amount.

Also, how do you want the firing order to work? With 1,2,3,4,5,6 you would get a v-twin with 90° or 450° interval between left and right bank.
The sound of the teaser also doesn't correlate with your idea.

[godlameroso]

How many main journals do you suppose the crank has then? 4? 3? 2?

[wuzak]

How many main journals do you suppose the crank has then? 4? 3? 2?

3.

The rules require it.

Edit: after I posted it I realised you are referring to the main crank shaft bearings, not the big end bearings. I would think 4 - one at each end and one between the crankshaft throws.

[glenntws]

How many main journals do you suppose the crank has then? 4? 3? 2?

Just like wuzak said. 3 crankpins and 4 main journals.

4 would be normal and anything else probably is just a theory. With these high rpm and pressures, you definetly need the support of all 4 points. And also, the spacing between cylinders can't be reduced so...

[wuzak]

The biggest problem however is the space you need for this to work. The radial space of the crankcase would need to be increased by a big amount.

I think also that the typical F1 engine has each cylinder pair in a separate chamber, with its own oil scavenge pump.

I believe it adds to the strength of the block and stabilises the main bearings.

You cannot do this with the joined cylinders.

[glenntws]

The biggest problem however is the space you need for this to work. The radial space of the crankcase would need to be increased by a big amount.

I think also that the typical F1 engine has each cylinder pair in a separate chamber, with its own oil scavenge pump.

I believe it adds to the strength of the block and stabilises the main bearings.

You cannot do this with the joined cylinders.

Possibly yes, but that would add sooo much weight... In general, the most important part of a v-block is keeping the v in it's position and the main bearings as strong as possible. Adding a increased barrier on the bottom wouldn't help very much. But who knows what these guys do...

[roon]

The block isn't shorter, only the crank. This was the original rumor. Which leads to: why? To accommodate something.

Regarding crank: rules specify journals, not throws, as mentioned. Main bearing quantity also not specified.

Side loading of the conjoined piston could be dealt with using a bearing surface. 2 linear bearings either side could handle conrod loads, alleviating the cylindrical portions of the conjoined piston i.e. frictional losses not necessarily worse, could even improve with optimized linear bearing and oil supply. I've seen small high-RPM two-stroke engines & big ship engines with linear and/or secondary bearings which decouple the piston from side load.

[wuzak]

The block isn't shorter, only the crank. This was the original rumor. Which leads to: why? To accommodate something.

I think if the block is shorter so is the crank.

The crank has to connect to timing gears at one end and the output shaft at the other.

[roon]

True, but the free space created would only be used on one end for the mgu-k. The other end could carry the geartrain.

godlameroso- Two main bearings, as I've drawn it. One throw carrying the mandated three conrod journals.

[PlatinumZealot]

Ok. Do you think that wazari gave us ALL of the firing orders that the engine uses for various reasons? Whether it is warm up, cool down, or some other strange reasons?

Could it be an on-the-fly change in firing order?

Surely the firing order is fixed by the crankshaft layout, the cylinder layout (ie 90° V6) and the camshaft timing, since that cannot be variable as per the rules?

I worked them out geometrically first withougt the camshaft timing accounted for. But the computer can still fire the spark plugs or not on any stroke. Some cylinders would be skipped over i guess. It is just a crazy idea. Would have to examine the cam timing as you say. As you are right the intake valve opening event will determine things ultimately.