whats wrong with the renault engines?

[Holm86]

I'm puzzled by the "waste gate gets used some of the time" assertion. I was under the impression that that was banned in the regs.

They're used as a fail-safe device in case of mgu-h malfunction which could cause catastrophic ICE failure.

Sure – I know they exist, and they're used as a fail safe, but the assertion above is that they use it in normal running.

Aside – this may go some way to explaining why RedBull have heat issues – using the waste gate would imply dumping extremely hot air into the body of the car, which would naturally cause them to get a surprise on the amount of cooling needed.

Where does it say that its in use under normal conditions?? And why should it be illegal??

[mrluke]

I'm puzzled by the "waste gate gets used some of the time" assertion. I was under the impression that that was banned in the regs.

They're used as a fail-safe device in case of mgu-h malfunction which could cause catastrophic ICE failure.

Sure – I know they exist, and they're used as a fail safe, but the assertion above is that they use it in normal running.

Aside – this may go some way to explaining why RedBull have heat issues – using the waste gate would imply dumping extremely hot air into the body of the car, which would naturally cause them to get a surprise on the amount of cooling needed.

Its quite clear in the technical posts above.

mgu-h is not banned in the regs.
mgu-h is not just a fail safe device.
wastegate is not causing RBR heat issues.

it is apparent that the current mgu-h technology does not have sufficient ability to be the sole boost control, it appears that a WG is being used to manage boost spikes where the mgu-h cannot react quickly enough. In addition there is presumably a point where boost control by braking the turbine causes a restriction to the engine and it becomes necessary to control the pressure with assistance from a traditional WG.

Finally the wastegate exhaust is highly likely to be plumbed in to the main exhaust. The heat issue is extremely likely to be caused by the "air cooled heat sink" referred to in the technical post which was receiving far more thermal load than Renault expected. I am at a complete loss as to why Renault have chosen to use this air cooled heat sink or why it could be preferably to a traditional wg.

Can anybody else expand on that last point?

[Harsha]

Firstly the Inside INFO was spectacular and it shows the Renault problems are over exaggerated
Can Renault update their software after March 1st which is the date where Engine spec must be submitted for FIA
Is restriction for engine or also for software updates ??

[basti313]

Can anybody else expand on that last point?

Maybe:
1. You can mount the heat sink where you want it to be. By controlling the turbocharger with a wastegate you have alle that heat at the wastegate right next to the turbo.
2. You can control the turbocharger more precisely with MGU H than with a wastegate -> drivability.
3. Speed of exhaust gas would be constant -> aero?

[dren]

Finally the wastegate exhaust is highly likely to be plumbed in to the main exhaust. The heat issue is extremely likely to be caused by the "air cooled heat sink" referred to in the technical post which was receiving far more thermal load than Renault expected. I am at a complete loss as to why Renault have chosen to use this air cooled heat sink or why it could be preferably to a traditional wg.

Can anybody else expand on that last point?

I'm pretty sure the WG has to dump into the exhaust exit past the turbine.

[Abarth]

Renault wanted to dump MGU-H energy into resistors in transient conditions. This in the case this very energy cannot be dumped into ES because full and MGU-K because the driver would not demand torque. The resistors need to be cooled, hence the heatsink mentioned.
And these transient conditions seemingly had a bigger share in the total load profile than expected, overheating the heatsinked resistors.

So what to do? Going brute force (so to speak) and using the wastegate, bypassing the exhaust turbine, instead of controlling it's speed by loading the MGU-H.

[Blackout]

And as basti313 said, they can place the heat sink almost where they want while with a wastegate they have much less freedom...

[dren]

But they shouldn't be running into problems overloading the ES. Either they are not using the ES enough, are filling it too much from the MGUK or the ES is just too small capacity wise.

[rjsa]

In another Forum, an insider (thats for sure) gave a fantastic information about the Renault issues and how they will solve them:

For those interested. Here are some of the changes Renault have made since Jerez.

Change of battery cell provider. The individual cells that make up the Energy Store have individual over-charge and over-discharge protection. These were proving unreliable due to thermal/vibration issues. Whilst the energy store is sealed in our fitment, I am informed the cells are now supplied by Panasonic.

Change to MGU-K to Crank drive gearing. The original torque multiplication factor was calculated to give a wider spread of torque on acceleration. Track testing found that this was causing traction dificulties and overloading the gearset and causing failure of the crank casing.

Change to turbocharger wastegate function. Renault had originally intended for the H to regulate Turbine speed in 95%+ of normal running. They facilitated this by allowing the H to pull charge (when the energy store was at capacity) to an air cooled heat sink. This strategy proved ineffective in certain environments and a more coventional wastegate is now being used to supplement the H.

Due to both the change in K gear ratio, boost control strategy and the energy store, most of the software relating to the charge and discharge cycling has been modified daily and continues to be refined. There are still issues relating to turbine speed control via H but these are mostly to do with fine tuning of the control software and the syncronisation between H control and wastegate control.

There has been swift progress and software related driveability now appears to be the main issue.

That's the second 'insider' over there. The first one didn't survive lat weeks test, his fixes didn't work. Lets see what happens now.

[basti313]

But they shouldn't be running into problems overloading the ES. Either they are not using the ES enough, are filling it too much from the MGUK or the ES is just too small capacity wise.

I also do not know how they can run into these problems:
-Battery capacity is defined by the regs (4MJ).
-They can only feed half of the battery cap with MGU K (2MJ).
-MGU H has about 100kW -> 2MJ=2000kWs -> 20s full power

So if you just use all the power you feed by MGU K and sometimes you just harvest a bit less your batteries can never be full.

I think this was just a combination of problems starting from the batteries, that burns your heatsink (hole in the bodywork?). With working batteries the problem should not exist.

[smlbstcbr]

Well, in a matter of hours we will see how wrong the Renault engines still are. If they cannot manage to make a decent race simulation, then I think it will be game over for the Renault teams. Ferrari and Mercedes in no way are going to let the FIA to concede an extension of development to Renault if they aren't allowed to do the same.

[rayden]

I'm assuming Renault are asking for the deadline for all manufacturers to be shifted, not a Renault only deadline?

[autogyro]

I think the aero gods are very unhappy at present.

Thunder and lightning is disturbing their once secure domain.

[turbof1]

Only the FIA determines a continuation of the development; the other teams/engine manufacturers don't necessarily have to agree with this. The FIA has the final say in this.

HOWEVER, alterations beyond the point of homologation need to be motivated properly. Renault succeeded once to argue they had a performance dificit. Ferrari succeeded in arguing they had reliability issues. Renault tried a second time to allow performance upgrades, but that failed.

Moreover, the requested alterations get pasted around to the other teams and engine manufacturers, right into the details. If they feel those alterations show 'hidden' performance upgrades, they can always put in a formal protest.

It's a trade-off you have to make: you can get more competitive this way, but you're also risking to show intriguing parts of your engine to the competition.

[R_Redding]

There is no need for Renault to panick over Homologation.

The appendix 4 Homologation chart is very generous and gives them years before major items changes are locked in ,to the point where they need to consult with the other engine manufacturers.
They can still change 61kgs of the weighed 66kgs total upto 2016
This is the current Homologation schedule ....



http://www.fia.com/sites/default/files/ ... -01-23.pdf

Rob