Can KERS fire the engine?

[safeaschuck]

Come on people, your missing the obvious here! you wouldn't rely solely on KERS for things like re-starting the engine and reversing because there is no guarantee it will be charged when you need to use it! Especially if you reverse and then stall. DOH!

[RH1300S]

A really interesting question.......I would only ask "why?"

These days the cars have anti-stall devices - so rarely (never) get stalled during a track incident. In the pits they always have a guy with the starter handy - I'm sure he can spin the engine up just as quickly as having an onboard device.

Reverse gear - interesting idea & why not? Even if the KERS drives the transmission rather than the engine - I don't see why it couldn't run backwards (of course, I wouldn't see why not - cos I don't understand how it works )

[pitlaneimmigrant]

Safeaschck, the Li batteries used are never run 'flat' by a KERS release as there is a minimum operational voltage for the cells, so although they could be near the minimum voltage limit, there would almost certainly be enough there to crank the engine. It could be a different story though if you have a mechanical KERS system.
And as RH (and a few others mention) the anti-stall software means this scenario occurring on track is very unlikely.
As for reversing, the electric systems have the physical capability but I doubt the software would allow it. In practice you would use the KERS to fire the engine then reverse under engine power. If you're reversing with KERS you obviously need to fire the engine anyway, so you might as well do it first.

[Michiba]

I know the discussion is can the KERS fire the engine, but even if it can I think it would be too impractical because as mentioned earlier, it had been designed for a very specific purpose, ie at high speed/revs.

Plus, what if you'd just used it to overtake or to boost lap times at an optimal part of the track, would it mean that you can't use it again on that lap to start the car?

[pitlaneimmigrant]

The software allows the KERS system to start the car. Even if the 400kJ limit had been reached just before the engine stalled, when the car is put into start mode the KERS counter is reset so any remining energy could be used to start the car

As riff_raff suggests I imagine things would be more difficult with a CVT system, especially if the positioning of the CVT is done hydraulically as no engine speed = no hydraulic pressure.

ESP, I suppose you could call the electric KERS system an overgrown starter motor, but if that wasn't there you wouldn't bolt a starter motor to the car. You would have the weight of a motor and larger battery just for the unlikely situation of the the driver stalling, Anti-Stall failing, and it not happening in the pitlane or on the grid. Given how much work goes into shaving grams from components I just can't see it happening

Ian, the software already allows the car to be started using KERS if so desired. However, I don't think it would reduce the number of guys in the pit crew as (a) everyone there has a second function and (b) you'd need a backup in case the KERS start failed.
If Max was really concerned he could just make another random rule limiting the number of guys over the white line. A lot of series' have it. Or better yet limit the number of FOM passes for each team and watch the engineers jump off the pit wall to help with the pit stop I would pay to see that!

[dp35]

I thought I heard on the practice or quali broadcast that the rules state that KERS can only be used at speeds above 100kph.

If this is true, then using the KERS while stopped to re-fire the engine would violate the rules.

[ISLAMATRON]

I thought I heard on the practice or quali broadcast that the rules state that KERS can only be used at speeds above 100kph.

If this is true, then using the KERS while stopped to re-fire the engine would violate the rules.

I think they cant recharge below that speed... they might still be power out KERS below 100kph.... not sure though.

I know they cant recharge while in the pit lane.

[pitlaneimmigrant]

I wasn't aware of any recovery or release restrictions based on car speed.
The recovery is triggered by brake pressure and the map selected by the driver, release is triggered by a button press, throttle position and another map.
Input/Output is limited to 60kW with no more than 400kJ per lap

I have heard people talking about releasing above 100km/h as 'optimal' due to wheelspin at low speed. KERS is allowed during starts which is obviously less than 100kph and if you were braking into a slow hairpin you wouldn't want 60kW of rear braking to suddenly disappear so turning it off at 100km/h wouldn't be popular.

[Tech_Racer]

I just checked the regulations (they aren't as difficult to read as you might think) and found this little gem:

9.9.4 The KERS must shut down when the ECU required by Article 8.2 initiates an anti-stall engine shut off.

But now I'm confused - - What is an anti-stall engine shut off?

[ISLAMATRON]

engine kill switch, or when they cut it off in the pits

[pitlaneimmigrant]

An anti stall engine kill occurs if an anti-stall takes place and the driver does not respond within a certain time, 10 seconds I think. This is so that in the event of an accident if the ECU prevents the engine stalling the engine will still be turned off if the driver is unable to do so.

I the driver turns the engine off, e.g on the grid or after an accident this is just referred to as a driver kill