23 replies to this topic

[Todd]

In Car and Driver's March, 2012 review of the Mercedes SLK55 AMG, they report that they were told by Mercedes-Benz that the cylinder deactivation system used in the car is based on the cylinder deactivation system they started using in Formula 1 in 2006. Has anyone heard of cylinder deactivation being used in F1?

[jatwarks]

In Car and Driver's March, 2012 review of the Mercedes SLK55 AMG, they report that they were told by Mercedes-Benz that the cylinder deactivation system used in the car is based on the cylinder deactivation system they started using in Formula 1 in 2006. Has anyone heard of cylinder deactivation being used in F1?

I believe that all the engine suppliers to F1 use it, for the following reasons.

On the start line the engines run on 4 cylinders to reduce fuel consumption and overheating.

After passing the chequered flag the engine is again switched to 4 cylinders to save fuel.

I also believe that the technique can be used during the race to offer the optimum combination of power and torque, but someone better qualified than I will have to give a detailed explanation.

[Ross Stonefeld]

When they had to carry race fuel weight in the third qualifying session(starting in 2006) it was important to run as many laps as possible so the car was at its lightest for it's final timed lap.

This made being the first car out of the pits important. But if you went to the end of the pitlane and sat for a while so you were first in line, you'd overheat. So Mercedes, and I think Honda, had like a super-idle setting for sitting still until the pit exit opened.

[Bloggsworth]

Martin Brundle described this in commentary several years ago - Much easier to do with electronic ignition and fuel injection, and I'm not sure that it was an F1 invention; I believe it was introduced by American manufacturers to meet the requirements of fleet fuel consumption.

[BRG]

In the current edition of Motorsport, Patrick Head writes about the Williams FW14 and mentions that its traction control system worked by cylinder deactivation. That was in 1991.

[Bloggsworth]

General Motors was the first to modify existing, production engines to enable cylinder deactivation, with the introduction of the Cadillac L62 "V8-6-4" in 1981.

More info here

[jatwarks]

In the current edition of Motorsport, Patrick Head writes about the Williams FW14 and mentions that its traction control system worked by cylinder deactivation. That was in 1991.

Using this for traction control became common; I don't know how the subsequent banning of traction control effects the use of cylinder de-activation for other purposes today.

It's all in the software. Presumably, the use of a common ECU controls the use of software effects on engine performance? There again, blown diffusers highlighted major differences between teams and engine suppliers!

We definitely need the opinion of one of our resident experts on this.

General Motors was the first to modify existing, production engines to enable cylinder deactivation, with the introduction of the Cadillac L62 "V8-6-4" in 1981.

More info here

I vaguely remember Top Gear featuring such a car on TV, but thought it had more than 8 cylinders! Wasn't the car they featured a V12?

I remember thinking "how can a car be termed 'economical' when running on 4 cylinders, and carrying a spare V8!".

[Bloggsworth]

Using this for traction control became common; I don't know how the subsequent banning of traction control effects the use of cylinder de-activation for other purposes today.

It's all in the software. Presumably, the use of a common ECU controls the use of software effects on engine performance? There again, blown diffusers highlighted major differences between teams and engine suppliers!

We definitely need the opinion of one of our resident experts on this.


I vaguely remember Top Gear featuring such a car on TV, but thought it had more than 8 cylinders! Wasn't the car they featured a V12?

I remember thinking "how can a car be termed 'economical' when running on 4 cylinders, and carrying a spare V8!".

Efficiency - A V8 on small throttle openings is very inefficient, much better to work 4 of the 8 harder.

[J. Edlund]

Cylinder deactivation was introduced in F1 to reduce problems with overheating during standstill.

Cylinder deactivation systems on production cars tend to be more complex, like those used by General Motors since the 80'ties. Those systems also deactivate the inlet and exhaust valves, and not only cut injection and ingniation. This is done in order to reduce pumping losses at part load.

[gruntguru]

J, does the system cycle the deactivated cylinders?

[x-ondrasek]

From Mercedes M152 (in SLK55) press release:

It is the AMG Cylinder Management cylinder shut-off system in particular, completely newly developed by Mercedes-AMG, which significantly improves efficiency: cylinders two, three, five and eight are cut off under partial load, which considerably lowers fuel consumption. In similar form this technology is also used in the approx. 750 hp V8 engines used in Formula 1. As efficiency also plays a major role at the pinnacle of motor racing, two or four of the eight cylinders are cut off e.g. when cornering at slow speed, in the Safety Car phases or for pit stops.

[desmo]

two or four of the eight cylinders are cut off e.g. when cornering at slow speed

You wouldn't have to be terribly bright to piggyback traction control onto that would you?

[jatwarks]

You wouldn't have to be terribly bright to piggyback traction control onto that would you?

My thoughts exactly.

With a common ECU how do different teams and engine suppliers manage to achieve such different effects as cylinder de-activation (traction control?) and, last year, blown diffusers, from engine mapping? Are they free to use their own software in the common hardware? That seems to nullify the purpose of the ECU!

Couldn't cylinder de-activation also be used in launch control?

[jimjimjeroo]

Couldn't cylinder de-activation also be used in launch control?

Interesting idea, I personally have no idea, but imagine someone here does!!

[Tony Matthews]

It was, as far as I know. Which is not saying much.

[MatsNorway]

Couldn't cylinder de-activation also be used in launch control?

BMW did this on their car. ignition cutting and so on during launch.

[saudoso]

My thoughts exactly.

With a common ECU how do different teams and engine suppliers manage to achieve such different effects as cylinder de-activation (traction control?) and, last year, blown diffusers, from engine mapping? Are they free to use their own software in the common hardware? That seems to nullify the purpose of the ECU!

Couldn't cylinder de-activation also be used in launch control?

To my knwolegde the traction control is avoided by the SECU because it won't factor acceleration and wheel spin parameters in it's algorithm.

So while you can tell the cylinders to misfire at a given engine speed and throttle position, you can't do that if the front and read wheels spin at different speeds or if the rear wheels accelerates faster than the car.

[BRG]

You wouldn't have to be terribly bright to piggyback traction control onto that would you?

According to Patrick Head in Motorsport, Williams engineer Paddy Lowe reckoned it only took him 15 minutes to write the code for their TC system.

[MatsNorway]

Its too many sensors in F1.... its keeping the costs up.. chop chop FIA...

[gruntguru]

Sensors are cheap. Now wind-tunnels - that's another matter.

[MatsNorway]

Sensors are cheap. Now wind-tunnels - that's another matter.

True but the paycheck is not high due to the sensor price. More down to a room full of engineers doing nothing but observing parameters on the car.

[Jovanotti]

I vaguely remember Top Gear featuring such a car on TV, but thought it had more than 8 cylinders! Wasn't the car they featured a V12?

It was a V16 actually which shuts 12 cylinders down --> guess you meant the Cadillac Sixteen (season 2/episode 10)..?

[jatwarks]

It was a V16 actually which shuts 12 cylinders down --> guess you meant the Cadillac Sixteen (season 2/episode 10)..?

That's it, I remember it being a Cadillac now. Even worse; an economy car (!) carrying around 12 spare cylinders, for just an occasional burst of performance!

[cheapracer]

Has anyone heard of cylinder deactivation being used in F1?

Yup, in 2006 the FIA deactivated 2 cylinders and will deactivate 2 more in 2014.