Starting ICE under own power

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
trinidefender
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Joined: 19 Apr 2013, 20:37

Starting ICE under own power

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Here is a quote by Jenson Button from the McLaren-Honda race report at the 2015 GP at silverstone, "The impact lifted the car up and turned it off. With the engine not running, I had no option but to retire."

It appears from this that there must be a sensor of some sorts that shuts off the engine in the event of a large shunt or if the wheels are lifted off of the ground. This is a very important safety device. Why though, can the 2014 and onwards power units not self start? If they had been able to then maybe jenson would have been able to simply start back up and re-join the race.

Before this generation of power units I can understand the problems with the extra weight of starters etc. Now however, it shouldn't take much more than a software update/new software mode. There could be two ways to start the engine.
1. The clutch is disengaged and since the MGU-K is connected to the crank all it has to do is rotate to a set speed and the engine will start just as if they used the starter mother from the back (hence where some teams have flaps in the back of their diffusers). The clutch is then engaged and the car pulls away and rejoins.
2. Same as number 1 but the clutch stays engaged the car getting up to speed also helps to roll start the car. 120kw should easily be enough for this.

Either I am missing something very obvious or Mclaren-Honda shot themselves in the foot by not including this. Or is there some reg that says once a car shuts off that it is out.

Cold Fussion
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Joined: 19 Dec 2010, 04:51

Re: Starting ICE under own power

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I've wonder this to, but it looks like none of the cars are capable of self starting or electric only running.

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ian_s
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Joined: 03 Feb 2009, 14:44
Location: Medway Towns

Re: Starting ICE under own power

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in the WEC the Toyotas pull away from their pit stops under pure electric power and start the ICE once they reach a certain speed. an F1 car surely should be able to do the same.

IIRC the original plan with the new engines was for the pit lane to be 100% electric power but the engine manufacturers didnt like that idea.

autogyro
53
Joined: 04 Oct 2009, 15:03

Re: Starting ICE under own power

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I think the reason is that the engine has to be turning for electric traction and it upsets other systems on the engine.

I have to say that the system I designed and which was looked on favourably by a couple of teams worked without connection to the engine and could easily drive the vehicle electric only or restart the engine on demand.

Unfortunately F1 is now definitely a spec series with different engine manufacture so there is NO scope for proper development.

Jolle
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Joined: 29 Jan 2014, 22:58
Location: Dordrecht

Re: Starting ICE under own power

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There was a plan to make the pitlane all electrical a few years back, but I guess there were to many extra systems needed on top of the already compacted hybrid PU.

Thinking of it, with an electrical motor having torque from 0rpm, with the right software and synergy, the PU could be clutches. or at least not in need of a clutch that can slip (to pull away from the start or pitstop). You could bring a car up to sufficient speed with electric power alone and then "put it into first".

Many years ago I had a Saab 96 V4 with a freewheel function on the gearbox (left there from the 2T days) and the clutch got stuck for a while. I could pull away starting the car in first and then shift trough the gears using the freewheel.

Tommy Cookers
617
Joined: 17 Feb 2012, 16:55

Re: Starting ICE under own power

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iirc the mu-k torque is limited to 200 Nm at the ICE crankshaft for all engine rpm
ie we do not have 120 kW available at low speeds
the mu-k is a good illustration that EM torque is proportional to the current limit (and so does not actually max at 0 rpm)

how much torque was needed to start a road car 1600 cc 6 cylinder engine using the starter handle ? - 200 Nm seems plenty

the road car starter iirc has a series wound field, its design is all about torque maxing very strongly at 0 rpm
in principle the current is rather unlimited, it can briefly draw hundreds of Amperes at the initial high load and near 0 rpm

is 200 Nm enough to drive the car electrically with a reluctant ICE as one could do with a road car starter ?
yes, most of the time

also if there is an open wastegate the ICE can become a weak (about 50 Nm ?) pneumatic motor (but not a self-starter)
as motoring the turbo by mu-h action can feed the ICE on 3+ bar air and exhaust it at 1 bar
and even become a residual heat motor (fuel-off)

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PlatinumZealot
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Joined: 12 Jun 2008, 03:45

Re: Starting ICE under own power

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Cold Fussion wrote:I've wonder this to, but it looks like none of the cars are capable of self starting or electric only running.
A technical director, who I can't remember right now, in 2014 said these engines can start themselves if it was required.
One reasons why teams don't do this currently could be because of temperatures and engine preparation? Possible two different power circuits? OR there is not pull-out mechanism? Remember the engine has kick-back when it is started.. this kick back is probably not programmed into the ECU... but it could be if they wanted to.
Last edited by PlatinumZealot on 07 Jul 2015, 00:46, edited 1 time in total.
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PlatinumZealot
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Re: Starting ICE under own power

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Anyway this topic has been done before: http://www.f1technical.net/forum/viewto ... =4&t=17774
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trinidefender
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Joined: 19 Apr 2013, 20:37

Re: Starting ICE under own power

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Maybe mods can merge these two threads then?

The temps shouldn't be a problem in jensons case as it had just been running from the start and should be well up to temperature. I have heard that argument before but I was always under the impression that it applies to why they don't start themselves in the pits.

When you say kickback what exactly do you mean?

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PlatinumZealot
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Joined: 12 Jun 2008, 03:45

Re: Starting ICE under own power

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Lets say the KERS as a starter turns at 2000 rpms. As soon as the engine fires there is a bump in engine speed to 4000 rpm. It creates a large back EMF on the starter. Since the KERS is a high voltage motor I was speculating that maybe this back EMF is a concern to the ERS electronics. Just guessing here...

There is a user named "Facts only" who has done some work involving KERS motors (or so he claims). He might be the best person to answer this. :-k
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langwadt
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Joined: 25 Mar 2012, 14:54

Re: Starting ICE under own power

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PlatinumZealot wrote:Lets say the KERS as a starter turns at 2000 rpms. As soon as the engine fires there is a bump in engine speed to 4000 rpm. It creates a large back EMF on the starter. Since the KERS is a high voltage motor I was speculating that maybe this back EMF is a concern to the ERS electronics. Just guessing here...

There is a user named "Facts only" who has done some work involving KERS motors (or so he claims). He might be the best person to answer this. :-k
I don't see why back emf would be a problem, that is what charges the batteries when harvesting

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PlatinumZealot
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Re: Starting ICE under own power

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Yeah you are right it would not be anything the System can't handle.
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Tommy Cookers
617
Joined: 17 Feb 2012, 16:55

Re: Starting ICE under own power

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presumably ......
there is an inherent limit to the response rate even an unloaded ICE to a step demand (startup being just a step demand)
and the mgu-k package response is by design integrated to the ICE response
and all possible 'bumps' in the engine speed (eg shifts) are driven by software maps

the equivalent of 'back emf' only occurs if the software tells the demand voltage to the mgu-k to rise slower than the PU rpm response
in principle the demand voltage can always be made to rise fast enough avoid any 'back emf' effect on startup
in reality the software could manipulate the demand voltage to make the mgu-k behave as a desengaging starter mechanism

technically - what's not to like ?

bhall II
473
Joined: 19 Jun 2014, 20:15

Re: Starting ICE under own power

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PlatinumZealot wrote:A technical director, who I can't remember right now, in 2014 said these engines can start themselves if it was required.
Yep. Apparently, it was even attempted just prior to the start of the last race, after Nasr's car broke down on the parade lap...

Image
via f1fanatic.co.uk

autogyro
53
Joined: 04 Oct 2009, 15:03

Re: Starting ICE under own power

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Allowing marshals to push the car with the electrics cycling is very dangerous for them.