Honda Power Unit Hardware & Software

[saviour stivala]

The primer pump is itself pressure feed and not gravity feed. It is itself pressure feed by the collector which is pressurized by the 3 or 4 lifter pumps used. The collector contains enough fuel to feed the primer pump continuously even if supply from lift pumps becomes intermittent at low fuel level with fuel sloshing about.

[saviour stivala]

The high pressure mechanical engine driven fuel pump supplies fuel to the injectors at constant and continuous pressure irrespective of engine RPM. The injectors can only control the fuel flow as per the needs of engine loads if they are feed at constant pressure. Because the fuel flow through the injector is controlled by the opening duration of the injector. The continuous constant pressure of the pump is controlled by a pressure regulator valve. The formula one direct injection fuel system does not use a pressure return line to tank as the fuel flow meter does its policing when the fuel leaves the fuel tank on its way to the engine.

[PhillipM]

Depends if it's boiling in the swirl pot. Then you're drawing vapours into the HP piston pump, they'll cavitate just as bad as anything if you have gas in the inlet line already.

[saviour stivala]

Depends if it's boiling in the swirl pot. Then you're drawing vapours into the HP piston pump, they'll cavitate just as bad as anything if you have gas in the inlet line already.

The formula 1 fuel system does not use a 'fuel swirl-pot' but uses a pressurixed fuel collector. Because collector is pressurized, fuel inside it is not swirling around. If fuel is boiling in the pressurized collector, it means that fuel have been pumped into collector alreadt boiled.

[holeindalip]

What temperature is the fuel in tank? For every 10kpsi you go up the temp increases by 30f?

[mzso]

What are the odds of the vacuum forming in the fuel cell? A failure of the vacuum breaker valve/breather whatever such device might be called.

There's no vacuum in the fuel cell.

[PhillipM]

If fuel is boiling in the pressurized collector, it means that fuel have been pumped into collector alreadt boiled.

Same thing, it's a collector to remove any air entrained by the lift pumps, in motorsport parlance that's a swirl pot.
Doesn't mean it was necessarily already boiling, maybe just the extra heat from the pumps, be that lift or supply, was enough to build more temperature.

[saviour stivala]

That they, A fuel swirl-pot and a fuel collector as used by F1 teams are aimed at preventing the same thing is a fact. But a swirl-pot proper functions differently from a fuel collector as used in F1. And that is why what is used in F1 it’s called a fuel-collector and not a swirl-pot. Assuming one believes what RBR is saying re-their findings after their investigation. They. RBR did not say that their encountered engine fuel starvation was caused by high fuel temperature.

[Eryngii]

Some images from ホンダF1のテクノロジー (Motor Fan illustrated Special Edition: HONDA F1 Technology Details)


2021 VIS (Variable Intake System):



2021 MGU-H Assy:


More images: https://www.as-web.jp/f1/796738?all

[Hoffman900]

Thank you for posting that!

I can't believe they find the flow losses around the bends in the intake path acceptable in terms of pumping losses as well as how it shapes the flow as it enters into the port. Dean vortices are very problematic. I never in a million years would have thought to have designed it like that as I have always been taught to straighten it out.

So quick thoughts:

Those runners are LONNNGG, especially when fully extending and making the duct work part of the runner length.

They are giving up flow resistance efficiency and peak power for (likely) aerodynamic packaging reasons and the gains in pressure wave tuning are offset whatever they are losing there. That is all about torque shaping.

[PlatinumZealot]

Yes partitioning the charge pipe into three adjacent tubes is weird but practical if they can minimise flow losses at higher flow rates.
I never thought that they would go this far when the news came out that they had used the charge pipe as an extension of the tintake runner... But this is somwthing else.


Another nice feature is the actuator. It is telescopic. You notice the actuator cylinder is short compared to the maximum stroke. Propbably some cable feed thingy inside of it.

[Hoffman900]

Does anyone know the minimum rpm these engines see on the track? About 7500, shifting around 10.5?

I’ll have to play with some math to figure out what is going on

[AR3-GP]

Thank you for posting that!

I can't believe they find the flow losses around the bends in the intake path acceptable in terms of pumping losses as well as how it shapes the flow as it enters into the port.

The air in the intake tract is pressurized. This reduces the flow losses associated with the bends. Flow at high pressure won't separate around the bends.

[Hoffman900]

Thank you for posting that!

I can't believe they find the flow losses around the bends in the intake path acceptable in terms of pumping losses as well as how it shapes the flow as it enters into the port.

The air in the intake tract is pressurized. This reduces the flow losses associated with the bends. Flow at high pressure won't separate around the bends.

This is false. I’ll type up a longer post later. Put a bend like that in an exhaust primary and you will kill power, and it’s at way higher pressure than the boosted intake side.

[AR3-GP]

Thank you for posting that!

I can't believe they find the flow losses around the bends in the intake path acceptable in terms of pumping losses as well as how it shapes the flow as it enters into the port.

The air in the intake tract is pressurized. This reduces the flow losses associated with the bends. Flow at high pressure won't separate around the bends.

This is false. I’ll type up a longer post later. Put a bend like that in an exhaust primary and you will kill power, and it’s at way higher pressure than the boosted intake side.

I'm not sure I know what you are referring to. I did not say that bends do not cause a performance loss in a pipe. Every kink causes losses at the inner radius of the tube. The kinks can also disturb pressure waves.

I only stated that higher pressure keeps more of the flow attached around the bends. This is exactly like how denser air would support sharper diffuser and wing angles before stalling.