TERS : Thermal Energy Recovery System

[henry]

Some sections are 2015 regs. Do they still say the same in 2019?
Other sections are personsl interpretation. It would have be most helpful to specify which parts are regulation and which are interpretation.
Or am I missing a source?

The source is thread “MGU-H Trickery” from July 2016. viewtopic.php?t=24261

This passage

This combined mix of electrical and ICE power/torque or any other contributed mix of power/torque as per the driver selected from on the steering wheel combination of deploy/harvest mapping, will go to the driven wheels as per the driver's throttle/accelerator pedal position request.

Confirms that the driver accelerator demand is fulfilled by a mix of ICE and MGU-H.

So we all seem to be on the same page now.

[saviour stivala]

The driver throttle/accelerator pedal demand (movement/travel 0 to 100) is fulfilled by a mix of electrical (through MGU-K) and ICE power/torque output, the level and mix of which depends on the mapping selected by said driver from on the steering wheel.
This mix of electrical and ICE power/torque output is delivered to the driven wheels through the crankshaft because the MGU-K is geared to the crankshaft at a ratio of 3.333;1, which means that when the crankshaft is rotating at max power speed of 10500rpm the MGU-K is rotating at 35000rpm outputting its max power/torque to the crankshaft.

Now as far as I know regardless of the interpretations, and regardless of the mix of electric/ICE power/torque map selected, the driver throttle/accelerator pedal travel (0 to 100 travel) controls the crankshaft RPM through the ICE throttle/s butterflies travel (0 to 100 travel).

Will repeat that, (1) the rules makes 2 exceptions to this driver throttle/accelerator pedal travel and the ICE throttle butterflies opening (travel) relationship. And (2) if said pedal/butterflies travel relationship wasn’t there the teams would be able to open a can of worms to ply with.

[Dr. Acula]

The driver throttle/accelerator pedal demand (movement/travel 0 to 100) is fulfilled by a mix of electrical (through MGU-K) and ICE power/torque output, the level and mix of which depends on the mapping selected by said driver from on the steering wheel.
This mix of electrical and ICE power/torque output is delivered to the driven wheels through the crankshaft because the MGU-K is geared to the crankshaft at a ratio of 3.333;1, which means that when the crankshaft is rotating at max power speed of 10500rpm the MGU-K is rotating at 35000rpm outputting its max power/torque to the crankshaft.

Now as far as I know regardless of the interpretations, and regardless of the mix of electric/ICE power/torque map selected, the driver throttle/accelerator pedal travel (0 to 100 travel) controls the crankshaft RPM through the ICE throttle/s butterflies travel (0 to 100 travel).

Will repeat that, (1) the rules makes 2 exceptions to this driver throttle/accelerator pedal travel and the ICE throttle butterflies opening (travel) relationship. And (2) if said pedal/butterflies travel relationship wasn’t there the teams would be able to open a can of worms to ply with.

Well, first of all the Gear ratio between the MGU-K and the Crankshaft isn't writen down in the rules. There are maybe teams which use a gear ratio of 3.333:1, but i think nobody here knows if all teams really do that. Yes, in theorie a 3.333 ratio would you allow to rev the ICE up to 15000rpm. But here's the thing, nobody revs that high.

What you control with a throttle pedal, regardless if drive by wire or not, is not the rpm of the engine. It's solely the torque output. Any rpm gain or loss is the result of increasing/decreasing torque.

And as so many already wrote before, with a drive by wire system, the driver has no direct control over the butterfly valves/throttle bodies. The electronics decide how to achieve the demanded torque output in the fastest and/or most efficient way possible. It's possible that the electronics opens the throttle more to achieve this, but it doesn't necessarily has to. For instance what could happen if you move the pedal rapidly from 0 to 70% and then keep it there? Well, i would expect that they use the full power of the MGU-K initially and then dial it back because of the limited energy the MGU-K has. But what does this mean mechanically? Well, when you dial back the MGU-K you need more torque from the ICE which potentially means the butterfly valves move although you keep the pedal at exactly 70% all the time.

[saviour stivala]

The driver throttle/accelerator pedal demand (movement/travel 0 to 100) is fulfilled by a mix of electrical (through MGU-K) and ICE power/torque output, the level and mix of which depends on the mapping selected by said driver from on the steering wheel.
This mix of electrical and ICE power/torque output is delivered to the driven wheels through the crankshaft because the MGU-K is geared to the crankshaft at a ratio of 3.333;1, which means that when the crankshaft is rotating at max power speed of 10500rpm the MGU-K is rotating at 35000rpm outputting its max power/torque to the crankshaft.

Now as far as I know regardless of the interpretations, and regardless of the mix of electric/ICE power/torque map selected, the driver throttle/accelerator pedal travel (0 to 100 travel) controls the crankshaft RPM through the ICE throttle/s butterflies travel (0 to 100 travel).

Will repeat that, (1) the rules makes 2 exceptions to this driver throttle/accelerator pedal travel and the ICE throttle butterflies opening (travel) relationship. And (2) if said pedal/butterflies travel relationship wasn’t there the teams would be able to open a can of worms to ply with.

Well, first of all the Gear ratio between the MGU-K and the Crankshaft isn't writen down in the rules. There are maybe teams which use a gear ratio of 3.333:1, but i think nobody here knows if all teams really do that. Yes, in theorie a 3.333 ratio would you allow to rev the ICE up to 15000rpm. But here's the thing, nobody revs that high.

What you control with a throttle pedal, regardless if drive by wire or not, is not the rpm of the engine. It's solely the torque output. Any rpm gain or loss is the result of increasing/decreasing torque.

And as so many already wrote before, with a drive by wire system, the driver has no direct control over the butterfly valves/throttle bodies. The electronics decide how to achieve the demanded torque output in the fastest and/or most efficient way possible. It's possible that the electronics opens the throttle more to achieve this, but it doesn't necessarily has to. For instance what could happen if you move the pedal rapidly from 0 to 70% and then keep it there? Well, i would expect that they use the full power of the MGU-K initially and then dial it back because of the limited energy the MGU-K has. But what does this mean mechanically? Well, when you dial back the MGU-K you need more torque from the ICE which potentially means the butterfly valves move although you keep the pedal at exactly 70% all the time.

If your interpretations of the relationship possibilities between driver throttle/accelerator pedal travel position and the ICE throttle’s butterflies travel position is correct, and allowed by the rules, as I have said, a can of worms would be pushed in front of the teams to open and play with.

[Tzk]

This can of worms has been open since the current engine regs were introduced. So since a few years now.

Regarding the mgu-k ratio:
I‘d assume that the mgu-k has a ratio of around 4 to the crankshaft giving you 50k rpm at the k when the crankshaft runs at 12500. iirc the engines run at around 11500 to 11800 in qualy mode.

[subcritical71]

I think it’s important that the current rules (2019) are looked at in this discussion. It seems Mr. Stivala is trying to apply rules that existed pre-2014 to the current rules. This seems to be where the confusion is being introduced. The current rules barely even mention the word ‘throttle’ (I believe only 2 or 4 times on my last search of the rules). The PU era is significantly different to that of any previous era regarding the usage and implementation of PU strategies, with the emphasis on efficiency.

[saviour stivala]

Whatever the differences in rules/eras the driver is in control by use of steering wheel, brake pedal and throttle/accelerator pedal.

[henry]

Whatever the differences in rules/eras the driver is in control by use of steering wheel, brake pedal and throttle/accelerator pedal.

Agreed. However, only the steering has a direct control path from the driver.

There is a direct route from driver to the brake pressure circuits but the SECU combines the MGU-K and modifies rear brake pressure to achieve what the driver requests. The accelerator is the same, the driver makes a request to the SECU and it decides how to fulfil it and issues commands to the ICE and Control Electronics. The driver also controls gear selection and just like the accelerator and brakes he makes a request to the SECU and it issues commands to the control electronics and hydraulics to fulfil that request.

So the accelerator is no different from the brake pedal and gear shift paddles.

[Dr. Acula]

I had a look at older Tech regs and found something intresting. In 2009 the wording was different.

5.5 Engine throttles:
5.5.1 The only means by which the driver may control the engine throttle positions is via a single chassis mounted foot pedal.
5.5.2 Designs which allow specific points along the pedal travel range to be identified by the driver or assist him to hold a position are not permitted.
5.5.3 The minimum and maximum throttle pedal travel positions must correspond to the engine throttle minimum (nominal idle) and maximum open positions.

But the 2013 rules already didn't mentioned the throttles anymore.

5.5 Engine torque demand :
5.5.1 The only means by which the driver may control the engine torque is via a single chassis mounted foot (accelerator) pedal.
5.5.2 Designs which allow specific points along the accelerator pedal travel range tobe identified by the driver or assist him to hold a position are not permitted.
5.5.3 The maximum accelerator pedal travel position must correspond to an engine torque demand equal to or greater than the maximum engine torque at the measured engine speed.The minimum accelerator pedal travel position must correspond to an engine torque demand equal to or lower than 0Nm.
5.5.4 The accelerator pedal shaping map in the ECU may only be linked to the type of the tyres fitted to the car : one map for use with dry-weather tyres and one map for use with intermediate or wet-weather tyres.
5.5.5 At any given engine speed the driver torque demand map must be monotonically increasing for an increase in accelerator pedal position.
5.5.6 At any given accelerator pedal position and above 5,000rpm, the driver torque demand map must not have a gradient of less than –(minus) 0.030Nm / rpm.

5.6 Engine control :
5.6.1 The maximum delay allowed, computed from the respective signals as recorded by the ADR or ECU, between the accelerator pedal position input signal and the corresponding output demand being achieved is 50ms.

If i remember correctly these rules were specifically introduced to prevent the use of a traction control. But the 2009 version is a really good example how not to write it. With the 2009 rules you could have open the throttle 1% when the pedal was at 99% because only 0 and 100% had to correspond.
Also if we just look back a few years further when they still used TC, they controlled it mainly by retarding the ignition timing and not by moving the throttle. So all in all the 2009 version of this rules was pretty pointless and were a much bigger can of worms than they are now.

[gruntguru]

If your interpretations of the relationship possibilities between driver throttle/accelerator pedal travel position and the ICE throttle’s butterflies travel position is correct, and allowed by the rules, as I have said, a can of worms would be pushed in front of the teams to open and play with.

His interpretations are indeed correct and there is indeed a "can of worms" available for the PU design team to play with. This is the case with any modern hybrid transmission where an Electronic Control Unit makes the final decision on how to mix mechanical and electrical energy to produce the torque level demanded by the accelerator pedal.

How can it be any other way? With accelerator position and the ICE rpm at a given setting, the command torque output might be say 300 Nm. This could be ICE 250 + MGUH 50 = 300 Nm. Under different circumstances the same accelerator/rpm setting might be ICE 300 + MGUH 0 = 300 Nm or ICE 350 + MGUH (-50) = 300 Nm. Without the "can of worms" to play with, the hybrid PU cannot be operated in the way the rules intend.

[henry]

As @subcritical71 mentioned the word throttle appears 4 times in the regulations, twice in Technical and twice in Sporting. Two mentions note that the physical components are exempt from the 3 ICE rule. One is about failsafe protection and the fourth, in the Sporting regulations under Start Procedure, has this, to my mind somewhat clumsy, section.

All drivers going to the pit exit at this time must do so at a constant speed and with constant throttle. This applies over the whole of the pit lane whether a driver is going to the pit exit from his garage or travelling through the pit lane between reconnaissance laps.

I assume they are trying to prevent driving against the brakes, or dipping the clutch and varying PU revs.

[Tommy Cookers]

in the Technology section of this site under the heading Features on page 8 and page 9 there is .....
an article on Torque Maps and an article on Throttle Maps

these seem to relate to the subject of 2013 rule 5.5.6 as in Dr.Acula's post
the 'constant power' torque maps coming with design freedom c.2009 had become the limit of possibilities in 2013
banning maps giving for all fixed accelerator positions torque decrease disproportionately greater than rpm increase
(had such maps existed they would have been inflammatory though not breaching established rules against Traction Control)
the 2013 rules are presumably the first limiting mapping to 2 dimensions

current map rules are essentially the same ...
'constant power' (limit torque/rpm value is different because engine is different) is the limit of mapping scope
'constant power' is more helpful (in the wet anyway) than traditional engine behaviour

aren't there 2 torque maps ? ie a 'designated wet weather' map and a default 'normal' map
how is rule 5.5.6 applied if there's these 2 cases ?

[Tzk]

You could start at a lower/higher point at 5000rpm and thus offset the whole torque map for wet weather. So for example 500Nm of torque for the dry map and 400Nm for the wet mapping at 5000rpm. I'm unsure if rule 5.5.6 only applies to the full throttle torque demand and thus if the teams may alter the part throttle map for better driveability on the wet weather mapping.

[saviour stivala]

If your interpretations of the relationship possibilities between driver throttle/accelerator pedal travel position and the ICE throttle’s butterflies travel position is correct, and allowed by the rules, as I have said, a can of worms would be pushed in front of the teams to open and play with.

His interpretations are indeed correct and there is indeed a "can of worms" available for the PU design team to play with. This is the case with any modern hybrid transmission where an Electronic Control Unit makes the final decision on how to mix mechanical and electrical energy to produce the torque level demanded by the accelerator pedal.

How can it be any other way? With accelerator position and the ICE rpm at a given setting, the command torque output might be say 300 Nm. This could be ICE 250 + MGUH 50 = 300 Nm. Under different circumstances the same accelerator/rpm setting might be ICE 300 + MGUH 0 = 300 Nm or ICE 350 + MGUH (-50) = 300 Nm. Without the "can of worms" to play with, the hybrid PU cannot be operated in the way the rules intend.

Implying that a can of worms is indeed available to the PU design team to play with is relegating the rule makers into a very bad light indeed. And in my opinion that is just not right and neither is it fair.
The ECU does not make decisions on how to mix mechanical and electrical energy to produce the torque level demanded by the accelerator pedal. the ECU Executes the mix level of electric and ICE power/torque as per the selected map from on the steering wheel by the driver. And the driver, according to 5.5 “power unit torque demand” = 5.5.1 “the only means by which the driver may control acceleration torque to the driven wheels is via a single foot accelerator pedal”. What does the driver foot accelerator pedal operates if not the ICE throttles? How will the driver be in command and driving the car if his foot demands 50% accelerator pedal travel and the ECU provides 75% or 25% ICE throttles travel?. If that function was allowed by the rules the first thing that will happen is the teams operating launch control and the second after that will be the teams operating traction control to name just two worms.

[henry]

You could start at a lower/higher point at 5000rpm and thus offset the whole torque map for wet weather. So for example 500Nm of torque for the dry map and 400Nm for the wet mapping at 5000rpm. I'm unsure if rule 5.5.6 only applies to the full throttle torque demand and thus if the teams may alter the part throttle map for better driveability on the wet weather mapping.

That was then, this is now

5.5.4 At any given accelerator pedal position and above 4,000rpm, the driver torque demand map must not have a gradient of less than – (minus) 0.045Nm/rpm.

I don’t think a simple offset would work. They still need to map maximum PU torque to 100% accelerator demand.