Renault Power Unit Hardware & Software

[F1NAC]

another problems today in FP1 with RIC engine

[Cold Fussion]

It was reported that the ICE in his car was a problematic unit from China and not a brand new engine problem.

[Long term F1 Fan]

One area I am struggling a bit in understanding is the MGU-H and its ultimate influence on overall power of the PU.

My understanding of the MGU-H is that it can recover the "heat energy" created from the hot exhaust gases blowing through the turbo charger and convert that into electrical energy to either add electrical power to the MGU-K or be stored in the energy store for later use. It also can power the turbo charger (keep it spinning to reduce lag and slow it down to act like a waste gate)
Does anyone know how much potential electrical energy can be harvested by the MGU-H and what does that translate into HP?

The reason why I ask is if the potential to harvest electric energy is significant (which would translate in more power to the MGU-K or have a larger amount of electricity stored for future use), it seems that it would make sense to have the MGU-H directly attached to the exhaust side of the turbo charger rather than the current Renault configuration of it attached behind the air compressor of the turbo. It would seem you could capture more heat energy that way and this potential is lost on the current Renault PU.

I know the split/non split turbo solution has been debated to death at this point, but without going to the extreme that Merc has done with their split turbo, it would seem that Renault would benefit from just separating the air and exhaust side of the turbo with the MGU-H (a la Ferrari???). All this of course would make sense if the MGU-H plays a significant role in the power equation.

Couldn't you also vary how to control the air compressor turbine and the exhaust turbine independently through some sort of clutch if the MGU-H is in the middle as opposed to just controlling the entire air/exhaust unit as one? Not sure that is allowed under the current rules, but again i would think the drivability and turbo lag would greatly benefit.

Any clarification on this would be greatly appreciated.

[trinidefender]

One area I am struggling a bit in understanding is the MGU-H and its ultimate influence on overall power of the PU.

My understanding of the MGU-H is that it can recover the "heat energy" created from the hot exhaust gases blowing through the turbo charger and convert that into electrical energy to either add electrical power to the MGU-K or be stored in the energy store for later use. It also can power the turbo charger (keep it spinning to reduce lag and slow it down to act like a waste gate)
Does anyone know how much potential electrical energy can be harvested by the MGU-H and what does that translate into HP?

The reason why I ask is if the potential to harvest electric energy is significant (which would translate in more power to the MGU-K or have a larger amount of electricity stored for future use), it seems that it would make sense to have the MGU-H directly attached to the exhaust side of the turbo charger rather than the current Renault configuration of it attached behind the air compressor of the turbo. It would seem you could capture more heat energy that way and this potential is lost on the current Renault PU.

I know the split/non split turbo solution has been debated to death at this point, but without going to the extreme that Merc has done with their split turbo, it would seem that Renault would benefit from just separating the air and exhaust side of the turbo with the MGU-H (a la Ferrari???). All this of course would make sense if the MGU-H plays a significant role in the power equation.

Couldn't you also vary how to control the air compressor turbine and the exhaust turbine independently through some sort of clutch if the MGU-H is in the middle as opposed to just controlling the entire air/exhaust unit as one? Not sure that is allowed under the current rules, but again i would think the drivability and turbo lag would greatly benefit.

Any clarification on this would be greatly appreciated.

whether the order is turbine-MGU-H-compressor or turbine-compressor-MGU-H doesn't matter. If a turbine can provide 100 hp (arbitrary figure) for use and the compressor draws 50 hp of that then 50 hp will be available to the MGU-H regardless of what order the components are, excluding losses from the shafts and bearings etc (frictional losses).

[langwadt]

One area I am struggling a bit in understanding is the MGU-H and its ultimate influence on overall power of the PU.

My understanding of the MGU-H is that it can recover the "heat energy" created from the hot exhaust gases blowing through the turbo charger and convert that into electrical energy to either add electrical power to the MGU-K or be stored in the energy store for later use. It also can power the turbo charger (keep it spinning to reduce lag and slow it down to act like a waste gate)
Does anyone know how much potential electrical energy can be harvested by the MGU-H and what does that translate into HP?

The reason why I ask is if the potential to harvest electric energy is significant (which would translate in more power to the MGU-K or have a larger amount of electricity stored for future use), it seems that it would make sense to have the MGU-H directly attached to the exhaust side of the turbo charger rather than the current Renault configuration of it attached behind the air compressor of the turbo. It would seem you could capture more heat energy that way and this potential is lost on the current Renault PU.

I know the split/non split turbo solution has been debated to death at this point, but without going to the extreme that Merc has done with their split turbo, it would seem that Renault would benefit from just separating the air and exhaust side of the turbo with the MGU-H (a la Ferrari???). All this of course would make sense if the MGU-H plays a significant role in the power equation.

Couldn't you also vary how to control the air compressor turbine and the exhaust turbine independently through some sort of clutch if the MGU-H is in the middle as opposed to just controlling the entire air/exhaust unit as one? Not sure that is allowed under the current rules, but again i would think the drivability and turbo lag would greatly benefit.

Any clarification on this would be greatly appreciated.

compressor and turbine must be permanently connected per the rules, so its doesn't really matter where the MGU-H
is connected

[mrluke]

The mgu-h doesnt really harvest the heat energy, its basically just boost control, it works as a brake on the turbo to prevent it overboosting and feeds the electric either straight to the mgu-k or ers. It can also act as a motor to spin the turbo up when the driver is off throttle so that full boost is always available

[langwadt]

The mgu-h doesnt really harvest the heat energy, its basically just boost control, it works as a brake on the turbo to prevent it overboosting and feeds the electric either straight to the mgu-k or ers. It can also act as a motor to spin the turbo up when the driver is off throttle so that full boost is always available

It takes the energy that would otherwise be wasted through a waste gate as noise and uses it to power the car, if that is not harvesting I don't know what it is

[gruntguru]

In fact it can probably harvest more than that. The turbine of a compound engine and its operating point (BP) are optimised to extract maximum energy from the exhaust with minimum energy cost to the piston engine - not just drive the compressor.

[Long term F1 Fan]

One area I am struggling a bit in understanding is the MGU-H and its ultimate influence on overall power of the PU.

My understanding of the MGU-H is that it can recover the "heat energy" created from the hot exhaust gases blowing through the turbo charger and convert that into electrical energy to either add electrical power to the MGU-K or be stored in the energy store for later use. It also can power the turbo charger (keep it spinning to reduce lag and slow it down to act like a waste gate)
Does anyone know how much potential electrical energy can be harvested by the MGU-H and what does that translate into HP?

The reason why I ask is if the potential to harvest electric energy is significant (which would translate in more power to the MGU-K or have a larger amount of electricity stored for future use), it seems that it would make sense to have the MGU-H directly attached to the exhaust side of the turbo charger rather than the current Renault configuration of it attached behind the air compressor of the turbo. It would seem you could capture more heat energy that way and this potential is lost on the current Renault PU.

I know the split/non split turbo solution has been debated to death at this point, but without going to the extreme that Merc has done with their split turbo, it would seem that Renault would benefit from just separating the air and exhaust side of the turbo with the MGU-H (a la Ferrari???). All this of course would make sense if the MGU-H plays a significant role in the power equation.

Couldn't you also vary how to control the air compressor turbine and the exhaust turbine independently through some sort of clutch if the MGU-H is in the middle as opposed to just controlling the entire air/exhaust unit as one? Not sure that is allowed under the current rules, but again i would think the drivability and turbo lag would greatly benefit.

Any clarification on this would be greatly appreciated.

compressor and turbine must be permanently connected per the rules, so its doesn't really matter where the MGU-H
is connected

Have a look at this article. Not sure how accurate it is - from 2014, but it is thought that Merc has decoupled the compressor and turbine via the MGU-H.

http://blog.axisofoversteer.com/2014/04 ... split.html

[Facts Only]

For the umteenth time, you cant decouple the two parts of the turbo (could somebody quote the rule yet again please?). The turbine and compressor must rotate about the same axis at the same angular velocity at all times.

That article is just bullshit speculation, the fact that they say that a large turbo creates lag shows that they have no understanding of what they are talking about, its not a 1980's 911 turbo trying to spool up out of a tight corner.

[stevesingo]

Something to consider is if a load is applied to the MGU-H the exhaust gasses will have to do more work and this in turn will increase exhaust back pressure pre-turbine. This will have a knock on effect on the efficiency of the ICE through both less efficient cylinder filling and increased pumping losses. The must be a cross over point where the energy delivered to the ES or provided to the MGU-K is less than the energy absorbed by the above losses. One way to alleviate this would be to vent excess boost from the compressor through a blow off valve, removing an additional unnecessary load from the compressor, allowing the turbine to spin faster and deliver more energy to the MGU-H.
Working on some ASSUMPTIONS
10500rpm
Max turbo speed 125k rpm
100kg/hr fuel
AFR of 14:1
1400kg/hr Air
VE of 120%
Naturally aspirated BMEP of 15bar
We need a boost pressure of 2.75Bar
If we size our turbo to deliver 1400kg/hr at 2.75bar max at engine speed of 10500rpm and turbine speed of 125k rpm, it will not have any excess heat energy remaining to drive the MGU-H, therefore I would suggest that the compressor is sized to deliver an output curve which delivers far in excess of that. The turbine is likely capable of driving said compressor to 125krpm from a much lower engine speed than 10500rpm. Any excess air can be bled off from the boost side of the plumbing with the balance of the load required to keep the turbo shaft below the 125k rpm limit provided by the MGU-H and generating power in the process.

I don’t believe that they are using the MGU-H alone to control boost pressure as it will have a detrimental effect on the efficiency of the ICE.

[FW17]

Have they sorted out that Piston issue? If they haven't, does it mean there is something fundamentally wrong with the engine?

[Vortex37]

Something to consider is if a load is applied to the MGU-H the exhaust gasses will have to do more work and this in turn will increase exhaust back pressure pre-turbine. This will have a knock on effect on the efficiency of the ICE through both less efficient cylinder filling and increased pumping losses. The must be a cross over point where the energy delivered to the ES or provided to the MGU-K is less than the energy absorbed by the above losses. .......cut.......

I don’t believe that they are using the MGU-H alone to control boost pressure as it will have a detrimental effect on the efficiency of the ICE.

@stevesingo

Renault are quite clear in this statement, that they have a wastegate. Which directly contradicts those on this forum who have stated categorically that they do not. I agree with your concept of a BOV (blow off valve) on the compressor side. As '@facts only' just stated above, these are racing turbo units, and not some ancient road car unit. I am convinced that the difference in these PU's is partly/mostly down to greater generator output from the MGU-H, by always having the turbo/generator running near to max allowed rpm. A BOV would easily allow this, as you mention in your post. But I would use a dual port device, to allow air to be sucked through the engine, which might be useful during lift and coast. Remembering that both wastegate and BOV can be electrically/hydraulically/pneumatically controlled.

[mrluke]

The mgu-h doesnt really harvest the heat energy, its basically just boost control, it works as a brake on the turbo to prevent it overboosting and feeds the electric either straight to the mgu-k or ers. It can also act as a motor to spin the turbo up when the driver is off throttle so that full boost is always available

It takes the energy that would otherwise be wasted through a waste gate as noise and uses it to power the car, if that is not harvesting I don't know what it is

That agrees with everything I said, it harvests energy but not really heat, it doesnt work like a heat pump, its really a brake on the turbine.

[stevesingo]

Something to consider is if a load is applied to the MGU-H the exhaust gasses will have to do more work and this in turn will increase exhaust back pressure pre-turbine. This will have a knock on effect on the efficiency of the ICE through both less efficient cylinder filling and increased pumping losses. The must be a cross over point where the energy delivered to the ES or provided to the MGU-K is less than the energy absorbed by the above losses. .......cut.......

I don’t believe that they are using the MGU-H alone to control boost pressure as it will have a detrimental effect on the efficiency of the ICE.

@stevesingo

Renault are quite clear in this statement, that they have a wastegate. Which directly contradicts those on this forum who have stated categorically that they do not. I agree with your concept of a BOV (blow off valve) on the compressor side. As '@facts only' just stated above, these are racing turbo units, and not some ancient road car unit. I am convinced that the difference in these PU's is partly/mostly down to greater generator output from the MGU-H, by always having the turbo/generator running near to max allowed rpm. A BOV would easily allow this, as you mention in your post. But I would use a dual port device, to allow air to be sucked through the engine, which might be useful during lift and coast. Remembering that both wastegate and BOV can be electrically/hydraulically/pneumatically controlled.

That is quite an old statement, but probably still the case.

I suppose the aim is to maintain the maximum permissible turbos shaft speed for MGU-H purposes whilst not exceeding the aid demand of the engine (by way of a BOV) and avoiding excessive exhaust back pressure (by way of a waste gate).