F1 engine RPM

[aussiegman]

You see, this is why no-one can be bothered to write a long reply to you, you deliberately take the statements out of context, misinterpret them, then apply them to a different condition anyway, brilliant.

Perhaps if you wrote something logical, that was substantiated by fact not anecdotal feelings then context may be less of an issue?

OK so I'll provide simple, individual responses:

1: I understood what you meant by "jerk" in this particular reference.

2: Regardless, I personally disagree with your conclusions with regard to holding an engine on the RPM limiter which is achieved via ignition cut for prolonged periods in so much as you believe this will cause no damage other than normal fatigue which are your words without a change in context as per the below;

3: So I categorically disagree with your statement below and that was referenced above:

you are not fatiguing the engine any more from varying the engine speed than you are with the compenents buzzing away 1rpm short of the limiter

Absolutely in my opinion you are, due to the magnitude and frequency of the torque impulse variations and the length of time this can be achieved by simply holding your foot down on the throttle.

4: Agreed, engine torque output variations occur constantly due to torque impulses from the combustion events (an engiens torque is not one smooth torque output, but a summation of torque impulses). In OEM engines these are traditionally dampened by harmonic balancers, dual mass flywheels, contra-rotating balance shafts or other methodologies as the impulse harmonics are deemed harmful to engine longevity (not only for NVH reasons). These systems are however not typically not present or are removed from racing engines, aside from servicable harmonic balancers on smaller cylinder count engines.

5: Regardless, as I indicated above, it is increases in time, magnitude and frequency of the torque impulses directly related to the RPM limiter which vary greatly from the impulses seen during normal operation that can result in failures;

5: Internal engine components experience forces associated with the change in speed of their motion due to the acceleration and deceleration of the engine (variations in RPM's). This is an immutable fact and mathematically definable;

6: The discussion diverged from F1 engines to more ubiquitous engines and the wire spring valve systems used therein,

7: With regard to your reference to F1 engines running on the limiter, as they run pneumatic valve systems vs. wire springs this relives "some" but not all of the components that can be prone to failure.

8: Pneumatic valve systems also have a higher tolerance for the harmonics and oscillations due to the use of a nitrogen chamber that replaces the spring. This is why they are used over wire spring systems. Lower mass, greater control, decreased harmonic & resonance influences and they are generally more robust due to overall and individual component design. F1 engines are typically more robust simply due to the extreme levels of engineering, materials used and testing provided for. These are typically cost prohibitive outside F1, even for other racing series and most certainly for other lower level professional and amateur series.

9: I have yet to see a similar pneumatic valve system available for OEM heads/engines that can be retrofitted for racing, if you know of one let me know;

10: The Williams FW34 of Maldonado running a Renault RS27 engine had a failure in Malaysia. This was reported as a piston failure by Renault. Rumor has it that yes the piston failed but only after it impacted a valve after a component in the nitrogen pressurisation chamber system in the head failed. Sepang Malaysia (I have raced there numerous times) is not only very hot, however with the two long and one short straights, forces an engine run near but also on the limiter more often then other tracks with shorter straights. It is believed this may have directly influenced the failure of the Renault engine in Malaysia.

11: Renault's commentary sounds suspiciously like engine manufactures spin, similar to an explanation once given by Juan Pablo Montoya after his Willaims-BMW failed leaving pieces of engine and casing strewn across the track. When asked in an interview what happened, with a great degree of sarcasm simply replied with something to the effect of "According to the engineers, it was an electrical failure, but not an engine failure..". BMW was notoriously protective of its reputation and Montoya has subsequently admitted he was "prep'd" to explain the failure was not due to the BMW powerplant. This is one on the reasons he had such a hostile relationship with some sections of the F1 paddock (that and his bad temper).

12: In 2012, other F1 engine failures have occurred this year at Bahrain GP for Charles Pic (Marussia Cosworth CA2012), Monaco GP for Heikki Kovalainen (Caterham Renault RS27) & British GP for Vitaly Petrov (Caterham Renault RS27)

13: In 2011 there were engine failures for Kamui Kobayashi (Sauber) British GP, Rubens Barrichello (Williams) German GP, Nick Heidfeld (Renault) Hungarian GP, Daniel Ricciardo (Hispania) Belgium GP, Vitantonio Liuzzi (Hispania) qualifying Japanese GP, Sebastian Buemi (Toro Rosso) Indian GP

14: In general, F1 engine reliability is up as the RPM's are restricted substantially below the maximum mechanical RPM limit that engineers had made them capable of running too. In 2006/07 it was 20,000rpm, then reduced to 19,000rpm in 2007/08 and now 18,000rpm.

15: Forces and wear increase exponentially as RPM's increase. A 2,000rpm decrease from 20,000rpm to 18,000rpm is a massive step down in the forces and wear seen by the engine components. That is exactly why it was mandated.

We will never agree, and as such I think this has gone as far as it can..

[AlpineF1]

heres an interesting fact on the subject

an f1 car idles at the same RPM that a normal car redlines at

[aussiegman]

heres an interesting fact on the subject

an f1 car idles at the same RPM that a normal car redlines at

Not quite (IIRC the Renault idles around 6,000rpm), but yes they idle high comparatively due to the very short stroke on the engines...

[strad]

I still agree with aussiegman. I have drag racing friends, you may or may not know that in many classes when they final stage they hold the engine against a rev limiter for the launch, that say it doesn't hurt the engine. I think they rebuild so often and when they blow it is a failure that can't directly be traced to that action. Can you look at a rod stuffed thru the block and determine whether the revving against the limiter played a part in weakening that rod or piece the broke that led to the rod failure? I don't think so. But it seems only logical to me that when you set up those kinds of vibrations that it is also only logical that it will find the weak link and snap it. Vibration in an engine is a killer.

[NoDivergence]

I have drag racing friends too. Look at the anti-lag that some guys run. They never hold it until they are 2-3 seconds away from launch. They try to avoid using it until they need to

[strad]

I'm not familar with anti lag..I assume you mean a retarding of the spark?

[raymondu999]

I'm not familar with anti lag..I assume you mean a retarding of the spark?

Turbo anti-lag perhaps?

[PhillipM]

I still agree with aussiegman. I have drag racing friends, you may or may not know that in many classes when they final stage they hold the engine against a rev limiter for the launch, that say it doesn't hurt the engine.

I've seen plenty of nitromethane fueled cars take damage from the limiter, but it's more from hydrolock due to the remaining charge left in the unburnt cylinder.

[riff_raff]

heres an interesting fact on the subject
an f1 car idles at the same RPM that a normal car redlines at

With an F1 engine, it's not so much the speed the engine idles at. Instead it's how much the rev's will drop when they drop the clutch. F1 engines have very little rotational inertia, so when they engage the clutch during a standing start the engine rev's can quickly drop and cause a stall.

Top fuel drag race cars are a bit different since they have no transmission. Their run is controlled entirely by clutch slip.

[aussiegman]

heres an interesting fact on the subject
an f1 car idles at the same RPM that a normal car redlines at

With an F1 engine, it's not so much the speed the engine idles at. Instead it's how much the rev's will drop when they drop the clutch. F1 engines have very little rotational inertia, so when they engage the clutch during a standing start the engine rev's can quickly drop and cause a stall.

Top fuel drag race cars are a bit different since they have no transmission. Their run is controlled entirely by clutch slip.

A quote from a Renault engineer was that their engine can go from 19,000rpm to zero in 0.2 of a second such as engine switch of in the garage.

Compare that to a production engine and you can start to see the differences.

[Greg Locock]

"A quote from a Renault engineer was that their engine can go from 19,000rpm to zero in 0.2 of a second such as engine switch of in the garage"

and you believed him?

[aussiegman]

"A quote from a Renault engineer was that their engine can go from 19,000rpm to zero in 0.2 of a second such as engine switch of in the garage"

and you believed him?

Umm, yeah why wouldn't I?? Regardless it sounded like it was in the right general vicinity. Have you tried timing or ever timed an F1 engine switch off event??

I've seen some logging and I wouldn't be surprised if it was sub 0.5s for a full RPM to zero no load switch of. There is virtually no flywheel and clutch inertia to keep it spinning and with such tight tolerances/high compression ratios a sizable amount of internal resistance to over come.

But hey what to I or they know..

[raymondu999]

Question - why would it slow down? Is there something that is slowing it down in a controlled fashion before the whole thing actually shuts off? Like a computer when it does its stuff first before finally powering down. Or is the 0.2 seconds just a function of air resistance?

[aussiegman]

Question - why would it slow down? Is there something that is slowing it down in a controlled fashion before the whole thing actually shuts off? Like a computer when it does its stuff first before finally powering down. Or is the 0.2 seconds just a function of air resistance?

The question should be: Why wouldn't it slow down??

It is a resistance thing as well as the mechanical effects of throttle shutting, fuel cut & spark cut. Most of an engines inertia is contained in the flywheel which is specifically designed to have a significant moment of inertia to resist reduce changes in rotational speed of the engine. F1 cars do not need this extra weight or rotational effect.

[raymondu999]

The question should be: Why wouldn't it slow down??

It is a resistance thing as well as the mechanical effects of throttle shutting, fuel cut & spark cut. Most of an engines inertia is contained in the flywheel which is specifically designed to have a significant moment of inertia to resist reduce changes in rotational speed of the engine. F1 cars do not need this extra weight or rotational effect.

I must rephrase. Why would it slow down that quick? I'd imagine an F1 engine would have more inertia. After all, you don't see the cars massively slowing down as they lift through corners such as Pouhon.