Why use starters with KERS?

[Giblet]

Is there any reason to not just use the 80HP electric motor directly coupled to the engine to start the car?

A car with no spindle and whatever else is required that adds size and weight (although I imagine not very much) would be better yes? Not having to carry the starter gear and backup as well can't hurt.

It would stop all this silly fidgeting around that opening for how little gain?

But if you want to win these days you need the best starter hole right? It shouldn't matter.

[strad]

Off the top of my head I find that interesting.

[Mystery Steve]

Isn't the engine clutch placed between the engine and KERS motors - meaning you would have to essentially "push start" the car the way you would with a regular car that has a manual transmission? I suppose you could add another clutch between the wheels and KERS motor, but that would be at the marginal cost of driveline efficiency and potentially reliability. I'm not sure which would offset the other: the omission of the starting equipment or the inclusion of additional driveline controls.

Or am I completely off base and the driveline schematic order actually goes: engine, KERS, clutch, and then wheels?

[antrock]

it is actually KERS - engine - clutch - gearbox

[WhiteBlue]

Its only for two years that we will have KERS. The MGUK which they will have from 2014 will also work as an electric starter. So the probability of making changes at the last minute for 2013 is extremely small.

[Mystery Steve]

it is actually KERS - engine - clutch - gearbox

In that case, I could see why you would want to use KERS as a starter. Do the rules mandate that you must have a mechanical starter, at least implicity, if not explicitly? Otherwise, maybe the teams don't want to rely on the KERS motor due to reliability issues? There was quite a few incidents last year where even top teams had non-functioning KERS at some point during the race, so they may just not trust the system enough to use it as the sole means of starting the car. I can't imagine the weight savings would be that significant anyway since it would seem most of the weight of the starting system is handheld by the mechanic, but I guess "significant" can mean different things to different people.

[hardingfv32]

Is the current KERS motor designed to function at almost zero rpm?

Wouldn't some kind of compromise be need to make it function at both ends of the RPM ranges?

Brian

[Richard]

At the moment the KERS is discharged when in the garage. So what charges the KERS to give it the power to start the engine?

[Pierce89]

Isn't the engine clutch placed between the engine and KERS motors - meaning you would have to essentially "push start" the car the way you would with a regular car that has a manual transmission? I suppose you could add another clutch between the wheels and KERS motor, but that would be at the marginal cost of driveline efficiency and potentially reliability. I'm not sure which would offset the other: the omission of the starting equipment or the inclusion of additional driveline controls.

Or am I completely off base and the driveline schematic order actually goes: engine, KERS, clutch, and then wheels?

Currently KERS is straight into the front of moter. Clutch is off the back towards gearbox

[hardingfv32]

Currently KERS is straight into the front of moter. Clutch is off the back towards gearbox

Would this imply that the KERS unit is always engaged to the crankshaft?

Brian

[Caito]

Harding, as I understand it, yes.
http://www.greencarcongress.com/2010/11 ... -7-kg.html

In Honda's case (very interesting article, btw) it has 5 gears to separate the electric motor from the engine.

If I'm not mistaken, if you're not drawing any current from the motor(hence, using it as a generator) the only losses you would have are friction losses.

[amouzouris]

i think i know the reason why teams don't do this..or maybe one of the reasons..they want the starter motor hole to extract more downforce from the diffuser!

[pitlaneimmigrant]

The idea was floating around when KERS was introduced but the functionality was never introduced to the standard ECU software. I guess it wasn´t deemed a necessity.
However, I believe the next generation of KERS equipped cars (2014 onwards) will have this ability as it is going to be requirement (unless this has changed recently) that all running in the pitlane is under electric power. So, KERS will need to be able to restart the engine at the exit of the pitlane

[Edis]

The reliability of the first and second generation KERS system haven't always been that good, and since there are no disadvantages with starting the engine with an external starter through the gearbox input shaft I suspect it simply wasn't considered necessary to add a starter functionality to the KERS system. The KERS system wasn't used instead of a conventional alternator neither, I suspect reliability worries was the cause for that too.

First generation KERS systems were generally designed so that they could be removed from the cars without having a negative impact on the cars. With the second generation KERS was more "permanent", because of that McLaren for instance switched to a combined battery/electronics unit placed in the fuel tank area which made the system several kg lighter.

The KERS motor is always connected to the engine.

KERS is not discharged when in the garage, disconnected perhaps but not discharged.