Engine mapping: qualifying "specials" banned

[Bruce D]

I've read this article about it Formula 1 and two things got me.

Firstly

previously it was possible to configure the engine maps to leave the throttle open and reduce the engine power by other means.

How on earth do they manage that. That I'd like to know. Cut spark to the plugs like traction control?

Secondly,

Furthermore, when the driver lifts fully off the throttle, the ECU maps must be configured to cut off the fuel supply to the engine - this is intended to prevent so called ‘hot blowing’ where the energy of the exhaust gas is increased by combustion.

Now maybe someone with a bit more knowledge of these engines can tell me, but if you stop the supply of fuel to the engine, wouldn't it stall?

[SGWilko]

I've read this article about it Formula 1 and two things got me.

Firstly


How on earth do they manage that. That I'd like to know. Cut spark to the plugs like traction control?

Secondly,


Now maybe someone with a bit more knowledge of these engines can tell me, but if you stop the supply of fuel to the engine, wouldn't it stall?

AIUI there are two ways to supply air to the EBD's when on the 'overun'

1. Keep the trumpets open below the airbox as if you were on full throttle, but not have full throttle fuel supplied - RB have argued that Renault do this to cool the valves (cold blowing - not be confused what the GF does after an iced drink)

2. Full throttle remains full throttle, but the fuel air mixture is burnt in the exhaust utilising a retarded ignition map, so there is no power transfer via the pistons (hot blowing, and increases fuel consumption by upto 15%).

If you consider that in modern engines on road cars these days, as you approach a junction using engine braking, the ECU automatically cuts off the fuel supply....

[Bruce D]

Thanks for that, these guys are so clever half the time it's scary.

[airshifter]

I've read this article about it Formula 1 and two things got me.

Firstly


How on earth do they manage that. That I'd like to know. Cut spark to the plugs like traction control?

Secondly,


Now maybe someone with a bit more knowledge of these engines can tell me, but if you stop the supply of fuel to the engine, wouldn't it stall?

What they are in effect doing is using spark and fuel control to keep the engine producing the desired throttle effect, yet the butterflies on the throttles remain mostly open so that the air is still pumping through the engine at near the rate as if the engine was running in actual "normal" wide open throttle conditions.

Most normal road cars these days use a DCFO, Deceleration Fuel Cut Off. Above a certain speed complete lifting of the throttle cuts fuel supply, and only the weight and momentum of the car is turning over the engine and accessories. For the power steering, alternator, AC, etc 2000 RPM is 2000 RPM, and it doesn't matter if it is created by a "running" engine or a coasting engine. Though it may seem strange, if you take a light road car and put it in one of the upper gears, it's not all that hard to push. When you have the momentum of the engine already in play, along with the mass of the car, it keeps spinning just fine on it's own without fuel.

The major difference is that for normal road cars, this takes place with closed throttles which results in a high vacuum situation and very little air pumping through the engine. The F1 guys have essentially figured out how to create a system that is almost throttle-less with very little actual movement of the butterflies under these conditions.



I'm not real happy with the idea of limiting mapping myself. They figured it out, let them use it. My other concern is how to police it. I would assume that any major team would adjust maps up to the last minute based on expected weather and such to obtain the maximum possible range of settings for the expected race conditions. Placing an earlier time on when changes are cut off may limit the teams on things not related to the blown exhaust conditions.

[555-04Q2]

Despite the ban RBR's Mark Webber is fastest by some margin.

[bluegem280]

In mostly free practice yes, he is good too at demonstrating different technique used in every sector, but in the real race the winner is SV.

[555-04Q2]

I think this "ban" could backfire on the FIA. Instead of penalising/slowing RBR, maybe its the other teams that lose out hock:

[Mia 01]

I think this "ban" could backfire on the FIA. Instead of penalising/slowing RBR, maybe its the other teams that lose out hock:

This.

[ioan]

The ban is only on one feature of the exhaust blown diffuser, it's about banning the part where the engines are revved high while driving around slower corners.
However, unless I am wrong, a driver can replicate these settings by using the throttle and brake pedal at the same time, sure is not the same as a pre-defined setting, however it can be done.

[SGWilko]

The ban is only on one feature of the exhaust blown diffuser, it's about banning the part where the engines are revved high while driving around slower corners.
However, unless I am wrong, a driver can replicate these settings by using the throttle and brake pedal at the same time, sure is not the same as a pre-defined setting, however it can be done.

I thought they were not allowed to change engine maps from qually to race from this weekend, and the hot/cold blowing will be banned from Silverstone.......????