Switching to four cylinders

[ClioSport197]

Hi all. I'm not sure if this has been asked yet but during Singapore under the safety car Martin Brundle said that the cars can switch to four cylinders in order to save fuel. Is this true? If so how do you think this is achieved?

Cheers
Tom

[freedom_honda]

im not sure if you can do that during the SC period but im pretty sure the cars automatically switch off some cylinders when idle.

http://en.wikipedia.org/wiki/Variable_Cylinder_Management
http://en.wikipedia.org/wiki/Variable_displacement

[Scotracer]

As freedom said, Mclaren have been able to turn off a number of cylinders whilst the car is idling so it can idle indefinitely.

I assume this can also be done on the track.

[mx_tifoso]

Yes, cylinder deactivation is now common on road cars, and IIRC at least only the McLaren Formula One team has developed a way to deactivate some cylinders for use when idling at the end of the pit exit. Although it's not improbable that some other teams also have that technology.

But I seriously doubt that cylinder deactivation is used in Formula One for the means of conserving fuel, since the engines are at WOT for most the time on track, and deactivating cylinders would reduce power, making them dead weight to carry around. Seems pretty illogical to say something like that IMO.

[panchito401]

Thats funny, I think Steve Matchett mentioned this as well while Massa was sitting at the end of the pit lane. I didn't know this was legal.

[panchito401]

He explained that it was a measure to control the temperature of the engine while sitting still. Not to nitpick Ferrari or Massa, but this was definately under the safety car if they did do it.

[Jersey Tom]

How to achieve it? I'd think it would be as simple as cutting fuel and spark completely from half the cylinders. Probably have to adjust fuel, spark advance, or throttle body trim slightly to maintain the idle speed on the remaining cylinders.

[ESPImperium]

They could have it as one of the engine maps.

But im pretty shure that they can select 4, 6 or all 8 cilinders for any part of the race, as to concerve fuel when under a saftey car period or on the parade lap, even on the out lap to the grid from parc ferme.

It could be done in with a RPM limiter as most cars have one to select in a engine map or a RPM selector on the steering wheel like the BMW Sauber.

[donskar]

Funny, multi-cylinder V8s are so common here in the USA that I never even thought of the possibility for F1. . . .

I wonder, though, wouldn't running a finely balanced V8 as V6 or inline 4 cause great imbalance and vibration? Not an issue with big US lumps. Exhaust tuning/scavenging would also be a factor to consider.

Can anyone provide the definitive word on this topic? Used in F1? Not used?

[rjsa]

They could have it as one of the engine maps.

But im pretty shure that they can select 4, 6 or all 8 cilinders for any part of the race, as to concerve fuel when under a saftey car period or on the parade lap, even on the out lap to the grid from parc ferme.

It could be done in with a RPM limiter as most cars have one to select in a engine map or a RPM selector on the steering wheel like the BMW Sauber.

It was previous to the SECU, but McLaren was known to stand longer idling and not moving due to cycling what cilinders are firing.

[ISLAMATRON]

Yes, cylinder deactivation is now common on road cars, and IIRC at least only the McLaren Formula One team has developed a way to deactivate some cylinders for use when idling at the end of the pit exit. Although it's not improbable that some other teams also have that technology.

But I seriously doubt that cylinder deactivation is used in Formula One for the means of conserving fuel, since the engines are at WOT for most the time on track, and deactivating cylinders would reduce power, making them dead weight to carry around. Seems pretty illogical to say something like that IMO.

It serves several functions actually, 1 is to save fuel, specifically when behind the safety car, they just turn off some of the fuel injectors(also some of the sprark plugs to keep the balance in the engine), but the main reason they have developed this is to be able to idle the car for a longer time period without over heating. It was developed last year when the cars would sit at the end of pit lane at the red light waiting for Q3 to commence.

[Conceptual]

I believe that all teams did this last year while waiting at the pit exit at the start of Q3 to prevent overheating. I also seem to recall reading that it is rather simple to achieve due to the 180degree crank shaft.

There was a large topic about this last year on the Speed Channel F1 message board. If you dig for it, I'm sure that you can find out about it.

[alexbarwell]

They can already switch to different fueling profiles which can reduce the fueling to each cylinder, if pneumatic valve control can be modulated then a reduced fuel-air charge would drop power output to a minimum without making that cylinder completely dead weight, but reducing the stresses involved. If this effect was scattered round every cylinder then every cylinder gets a breather and saves fuel. Remember the rest of the time components are under max stress so reducing this can hold things together better (like a second race for the engine or the last few critical laps of the current race). The weak firing scattered would sound very stuttery and random, but all cylinders rested similarly - if you save 7 and hole 1 you still get the long walk back.

[mistareno]

It is currently done completely electronically. The ECU cuts both the fuel and spark to four rotating cylinders per cycle. For example, if the firing order was - 1-8-7-2-6-5-4-3.

Then the first cycle would result in 1-7-6-4 and the next would be 8-2-5-3

It basically runs as 2 alternating 4 cylinder engines, there are pumping loses associated with the valves closing and the compression for the unused cylinders, but these also help balance the engine out.

It probably helps reduce heat soak at idle and reduce fuel consumption during 'parade laps'. It could concievably be used in race conditions as part of a fuel mapo to reduce fuel consumption by activating during off or part throttle applications, but there would always be a momentary delay (mil/second) between cylinder reactivation.

On a side note, is there anything in the current Traction Control regs that prevents a team setting up their ECU to provide a map that only allows the engine to increase revs at a predetermined rate dependant on gear?

Foe example, on a dry track, there would be a maximum rate of acceleration in each gear before traction was overcome. If the ecu only permitted that rate of engine acceleration you would effectively have a pseudo traction control without the need for wheel sensors or ignition cuts etc.

You could even set it up to allow a 105% maximum rate of acceleration to allow for a degree of attitude adjustment.

You could easily have a wet and intermediate 'map' also.

[alexbarwell]

Yep, think this might be why FIA opted for standardized ECUs as this back-handed traction control effect could be lost in the code somewhere and the FIA would spend a lot of time, effort and money trying to reverse engineer this, while the teams are cooking up the next trick.