437 replies to this topic

[munks]

Kers is the main reason for any connecting of engine to rear wheels under braking, certainly not car balance.

So before KERS, nobody had the engine connected to the rear wheels during braking?

You're of course correct that downforce enters into all this (again, all the parts of the car need to work together as I keep saying). Depending on where the aero balance is, engine braking and/or even KERS might be beneficial or detrimental to the balance, but can be adjusted by throttle and/or gear *if* there's a connection.

I think you will find that the benefits of having the engine connected to the rear wheels are far far outwayed by
the unbalancing of the car during down shifts which results and requires the fitting of a lock up diff to compensate in most cases.

Yes, yes, you've asserted this about 5x in this thread. No evidence for or against, so I'm not quite ready to take your word for it, sorry.

[Fat Boy]

Honestly, at what point can we just vote someone off the island?

[cheapracer]

Like I said, having the engine engaged is something you use to influence handling.

Couldn't agree more, with good drivers as I mentioned it supplements the brakes and chassis or can be used to cover deficits for either - but most drivers just waste their time trying to have control over the car to their loss and occasionally an engine loss too.

After driving a rotary to work this morning I can tell you they most certainly do. Less than a piston engine, sure, but still "worth mentioning."

Try a PP race car sometime.

Edited by cheapracer, 04 June 2011 - 07:13.

[24gerrard]

Err...how do the free-wheeling front wheels do more breaking than the rear during over-run?

Weight transfer from rear to front when brakes applied.
This loads the front tyres and makes them grip better.
On my mini the front pitch was increased to operate the camber/toe out changes on the rear beam axle.
(large increase in handling and control)
With 9 inch wide slicks on a mini the available front grip gave more than enough available brakeing on the front to equal
the maximum with a non 'diving' four wheel braked car of the same weight.

I would still match the concept up against a modern short oval Hot Rod (UK), with different chassis and engine of course.
The five speed electronicaly controlled fully automatic gearbox helped as well.

[Ross Stonefeld]

I get a tingle when I read 'beam axle'

[Tony Matthews]

BEAM AXLE! There you are Ross, just for you!

[cheapracer]

I get a tingle when I read 'beam axle'

A soon to be seen car is going to give you goosebumps then, front and rear beams.

[Catalina Park]

As long as it is propeller driven I don't care.

[Tony Matthews]

And twin out-boards...

[Canuck]

Weight transfer from rear to front when brakes applied.
This loads the front tyres and makes them grip better.
On my mini the front pitch was increased to operate the camber/toe out changes on the rear beam axle.
(large increase in handling and control)
With 9 inch wide slicks on a mini the available front grip gave more than enough available brakeing on the front to equal
the maximum with a non 'diving' four wheel braked car of the same weight.

I would still match the concept up against a modern short oval Hot Rod (UK), with different chassis and engine of course.
The five speed electronicaly controlled fully automatic gearbox helped as well.

I've misinterpreted your original statement. I thought you were implying that in an over-run situation, the front wheels would provide more drag than the engine braking without the brakes applied.

[24gerrard]

I get a tingle when I read 'beam axle'

Well we had a fun super saloon Capri with a rear beam 'driven' axle.
Now let me see if I remember.
Oh yes, it lapped Snetterton in 1 min 25seconds.
Much the same as the Rover 3500s with IRS.
On a run what you brung meet there, the fastest sports bike lapped it in 1 min 31seconds.
So much for macho bikers.
So what exactly is wrong with a 'beam' axle?
My BDA rally escort had one and that worked very well.
I forgot, you guys race fast cars hahaha.

[24gerrard]

BEAM AXLE! There you are Ross, just for you!

Might not be as silly as you think.
However the 'beam' geometry was OK for the mini but would not be needed in a modern version of the concept.
A variable geometry rear end on the Mercedes might even help with its poor performance.
Dont forget last year they shortened the wheelbase and it still didnt work.

Edited by 24gerrard, 04 June 2011 - 17:39.

[carlt]

Might not be as silly as you think.

Take a deep breath - Relax - maybe a glass or two of your favourite -

Did anyone mention anything about them being silly ?

[24gerrard]

Take a deep breath - Relax - maybe a glass or two of your favourite -

Did anyone mention anything about them being silly ?

I just have, a whiskey and dry.
Anyway its Golds thread on gearboxes, we should get back on subject.

[cheapracer]

Much the same as the Rover 3500s with IRS.

They had live rear axle (beam).

Presuming of course you meant a Rover SD1 3500 and didn't mean an actual Rover 3500 that no one raced seriously which had a split DeDion semi IRS (which belongs in the "Worst IRS" thread btw).

Edited by cheapracer, 05 June 2011 - 04:34.

[24gerrard]

They had live rear axle (beam).

Presuming of course you meant a Rover SD1 3500 and didn't mean an actual Rover 3500 that no one raced seriously which had a split DeDion semi IRS (which belongs in the "Worst IRS" thread btw).

I meant, we raced saloons with rear driven beam axles against cars with IRS (some were indeed Rover SDI 3500s).

The thread is about F1 gearboxes.
As you say, there are more relevent threads for the suspension debates.

I also pointed out some of the possible uses of brakes and gearshifting, that are not what most drivers would understand or consider.
Getting results with such things as 'beam' axles is a comparison supporting this from another area of car control and handling.

[cheapracer]

I also pointed out some of the possible uses of brakes and gearshifting, that are not what most drivers would understand or consider.

I'm luckier than most, from a young age I have ridden with some of the worlds fastest drivers and the disassociation they have with gearbox and brakes/chassis surprised me initially until I woke up to what they were doing (going a lot faster than me for one!).

[faaaz]

I got a slightly unrelated question for all the pros. When you need to downshift from say 4th gear to 2nd gear, do you engage the clutch once, and go from 4th straight into 2nd, or do u engage the clutch twice, 4th to 3rd, then again 3rd to 2nd?

[cheapracer]

I got a slightly unrelated question for all the pros. When you need to downshift from say 4th gear to 2nd gear, do you engage the clutch once, and go from 4th straight into 2nd, or do u engage the clutch twice, 4th to 3rd, then again 3rd to 2nd?

There is no rule unless the gearbox itself doesn't permit it such as a sequential.

Find Gary Sheehan's lap in the McLaren M6 at Laguna Seca and watch him at the Corkscrew come in totally on brakes and chassis then merely pops it from 4th to 2nd and takes off down the hill but I can also find you others who do it completely differently.

http://www.google.co...l...mp;aql=&oq=

[faaaz]

There is no rule unless the gearbox itself doesn't permit it such as a sequential.

Find Gary Sheehan's lap in the McLaren M6 at Laguna Seca and watch him at the Corkscrew come in totally on brakes and chassis then merely pops it from 4th to 2nd and takes off down the hill but I can also find you others who do it completely differently.

http://www.google.co...l...mp;aql=&oq=

Nice!

Senna does it by depressing the clutch twice in the road car

But in the mclaren he sounds as though he is engaging the clutch only once, not sure though

So you don't think one is more optimal than the other? Or perhaps one is more suited to race specs as opposed to a road car?

[cheapracer]

Nice.

So you don't think one is more optimal than the other? Or perhaps one is more suited to race specs as opposed to a road car?

It is "nice" and a perfect example of what I am trying to get across but there's other drivers who can do it just as fast bashing the gears down so I would be a fool to preach it's the only way.

There's just too many variables for car, track and driver. I believe Senna and Prost were entirely different on their downshifts in the same car (McLaren obviously), Senna went down one at a time religiously and Prost often skipped past gears, 4th to 2nd, 5th to 3rd etc.

It's a bit like golf, 50% of the field have a perfected "book swing" while the other half have idiosyncrasies that Golf instructors cringe at yet the winning is shared between the 2.

[faaaz]

It is "nice" and a perfect example of what I am trying to get across but there's other drivers who can do it just as fast bashing the gears down so I would be a fool to preach it's the only way.

There's just too many variables for car, track and driver. I believe Senna and Prost were entirely different on their downshifts in the same car (McLaren obviously), Senna went down one at a time religiously and Prost often skipped past gears, 4th to 2nd, 5th to 3rd etc.

It's a bit like golf, 50% of the field have a perfected "book swing" while the other half have idiosyncrasies that Golf instructors cringe at yet the winning is shared between the 2.

But I do remember reading somewhere on the forum that Senna had more issues with his gearbox than Prost ( May have been you?). So perhaps one method might be easier on the equipment, but in terms of speed, as you say, it doesn't matter.

Edited by faaaz, 11 June 2011 - 10:03.

[24gerrard]

But I do remember reading somewhere on the forum that Senna had more issues with his gearbox than Prost ( May have been you?). So perhaps one method might be easier on the equipment, but in terms of speed, as you say, it doesn't matter.

If you can cut the number of gear shifts down for the same lap times, then there will be less wear and load on the gearbox.

[bigleagueslider]

If you can cut the number of gear shifts down for the same lap times, then there will be less wear and load on the gearbox.

24gerrard,

Can you please explain your interpretation of the relationship between shift frequency and gearbox "wear and load".

When analyzing transmission gear and bearing fatigue lives, the accepted approach is to consolidate the life cycle speed and loads using a Miner's rule analysis. In such an analysis, more shift events would naturally mean each individual loaded gear would be subject to a lesser number of load cycles, all other things being equal.

On the contrary, as you suggest, fewer shifts per lap would mean that each individual gear is subject to a greater total number of load cycles. Which naturally would imply a shorter L10 fatigue life for those loaded gears.

Regards,
slider

[24gerrard]

24gerrard,

Can you please explain your interpretation of the relationship between shift frequency and gearbox "wear and load".

When analyzing transmission gear and bearing fatigue lives, the accepted approach is to consolidate the life cycle speed and loads using a Miner's rule analysis. In such an analysis, more shift events would naturally mean each individual loaded gear would be subject to a lesser number of load cycles, all other things being equal.

On the contrary, as you suggest, fewer shifts per lap would mean that each individual gear is subject to a greater total number of load cycles. Which naturally would imply a shorter L10 fatigue life for those loaded gears.

Regards,
slider

In theory absolutely true slider.

However, only if the gearbox is subjected to the maximum forces that are produced when it is used at its maximum potential and its use is calculated in isolation to all the other widely variable vehicle inputs and the compromises created by outside forces.
It is a conclusion based on much the same range of 'narrow' inputs, as when calculating gear shift speed and modulation.
Also, although each gear contact patch will gain less wear by not being subjected to anymore torque transfer than the others if the gears are used equaly, this does not take into consideration the varying loads on other 'train' components that are different depending on which gear is engaged. To start with, layshaft gearbox basic design has very 'uneven' burst loads due to the offset torque 'path'.

One simple example of your shorter L10 fatique life not applying absolutely in practice, is during short shifting and coasting, both techniques are used by the best drivers for a number of reasons, fuel saving, balancing brakeing and KERS use (not very well in the case of RB) and simply to reduce the very loads on the gearbox in question here.

The purpose of the gearbox is seldom appreciated by most people (even engineers).
Basicaly it is to match the road speed to the engine rpm at a time chosen by the driver, to achieve maximum vehicle efficiency and in the case of a racing vehicle, performance.
To conform to your 'fatigue life' conclusion, this can only be theoreticaly applied on a strait road at maximum vehicle acceleration and braking.
Even then there are many variables, so the closest figures could only be on a test rig.

Over the whole of motor vehicle development, gearboxes have in almost every case been 'over' engineered to take into account the
many varied loads that they are subjected to in use and to negate the highly complex and costly test work needed to calculate their capabilities.

F1 has forced a reduction in weight and size on gearboxes used in the sport.
This has resulted in the 'ultimate, form of high performance gearbox, this may be true.
However it is still based on the dated layshaft concept.
Not only is this layshaft concept totaly unsuited to future developments in Hybrid (F1 KERS) and electric vehicles, F1 regulations that have forced geartrain component weight and size reduction, have placed the geartrain in F1 cars as probably the weakest mechanical link in the powertrain.
I know for a fact, that at least one established racing gearbox manufacturer with the highest reputation no longer wishes to produce F1 gearboxes, because of the damage to reputations failures in use can cause when there is little if any way to prevent them when working in such a narrow design envelope.
The pressures from F1 regulations are in the wrong direction to encourage powertrain development for this century.

Edited by 24gerrard, 13 June 2011 - 09:20.

[Tony Matthews]

I wondered why there were so many gearbox failures in F1...

[Chezrome]

Bit off topic here...Is it a common practice to upshift through middle of a corner? If so does it affect the balance of the car much?

Not as much as a downshift does...

BTW:

I am a bit puzzled about the thread title, because I am driving a 1991 F1 in rFactor, and it's not the League Edition, but a historic version. Don't know where I got it, I think it's FSR. Another 1991 Mod?

[24gerrard]

Not as much as a downshift does...

BTW:

I am a bit puzzled about the thread title, because I am driving a 1991 F1 in rFactor, and it's not the League Edition, but a historic version. Don't know where I got it, I think it's FSR. Another 1991 Mod?

No gear shift should upset car balance if it is undertaken in a way that maintains a smooth torque transfer to or from the drive wheels.
It is 'sledgehammer' shifts that 'jerk' the powertrain that unbalance the car.
Unfortunately a jerk is usualy unavoidable with stepped layshaft gearboxes, so it is just a question of degree of jerk.

[cheapracer]

so it is just a question of degree of jerk.

The gearbox or the driver?

[gruntguru]

You bit your tongue there didn't you Cheapy?

[24gerrard]

The gearbox or the driver?

I thought you would say that.

[carlt]

I've driven a sequential car without neutral, and a combination lock to access reverse.

does this mean you had to remember the number , so that in the event of a spin you could unlock reverse ?

[24gerrard]

does this mean you had to remember the number , so that in the event of a spin you could unlock reverse ?

In such a case the car will almost certainly be out of the race with a stalled engine and no way to restart it.
No neutral and sequential layshaft is so ancient a concept it is untrue.
With my ESERU gearbox system you would simply rejoin , either in forward or reverse under electric power.
You would then restart the ic engine when ever you wished using the ESERU motor segments in the first annulus
to drive the first sungear engaged with the crank.
No chance of any missed shifts either.

[WhizzMan]

Okay, I'll bite.

What weight is this ESERU? How long is it? How big a battery would it require for practical use for KERS or hybrid drive? what's the total weight of the rotating mass? How would that compare to a motorcycle with less than 15 kg of rotating mass in the gear box at any given moment, including generator, clutch and fly wheel? How would the effect of this system influence a 150kg total weight bike?

What "jerk" would you get with an electronically interrupted ignition on a bike (kits could be purchased for retrofit 15 years ago in any performance bike shop) and a system like Kawasaki's KABATL for up and downshifts? I doubt it's significantly more than if you'd use a planetary system.

Most "classical" race cars don't have an electronically controlled dynamic brake balance setup. Using the engine to balance brake distribution between front and rear is a widespread and accepted technique in my book. With modern electronics you can have the computer control each wheels deceleration to the max and the engine brake would only get in the way.

[24gerrard]

Okay, I'll bite.

What weight is this ESERU? How long is it? How big a battery would it require for practical use for KERS or hybrid drive? what's the total weight of the rotating mass? How would that compare to a motorcycle with less than 15 kg of rotating mass in the gear box at any given moment, including generator, clutch and fly wheel? How would the effect of this system influence a 150kg total weight bike?

http://www.f1technic...c...2&start=375

Scroll down to pa including schematic.

Weight for F1 car would be around 20kg, for a bike, less than the current systems.
The rotating mass in the ESERU under deceleration assists balance between energy recovery and engine/brake balance.
It is comparable to a layshaft gearbox of the same size, LESS the clutch, which does not exist in the ESERU powertrain.
Simple answer, to save a few hundred pages, the system would improve efficiency and performance in any bike or car application.

What "jerk" would you get with an electronically interrupted ignition on a bike (kits could be purchased for retrofit 15 years ago in any performance bike shop) and a system like Kawasaki's KABATL for up and downshifts? I doubt it's significantly more than if you'd use a planetary system.

Ducati had problems with the early systems in bike racing, they are pretty well sorted today.
With bike gearboxes, the shifts are undertaken and controlled fairly well by the rider, although with a sequential barrel selector, there is little
modulation of shift available to the rider. Cutting ignition or using other automatic control methods to soften the shifts works OK.
However, my ESERU would add a new dimention of gearshifting and allow a complete ergonomical rethink for bike controls.

Most "classical" race cars don't have an electronically controlled dynamic brake balance setup. Using the engine to balance brake distribution between front and rear is a widespread and accepted technique in my book. With modern electronics you can have the computer control each wheels deceleration to the max and the engine brake would only get in the way.

Very true, however, how the gear shifts are undertaken by the driver and at what rpm and in what road situation has a direct control input to this balancing.
On modern cars (and bikes) with electronic gearbox control, the same applies, although the control given by electronics is seldom as variable or as good as manual control using a non barrel selected dog gearbox. (the shifts are not any faster)

In F1, the high downforce gives far more brake retardation than engine braking in almost all circumstances, so the need for balanced engine braking to achieve the best retardation does not exist to anywhere neer the same levels.
With KERS and the need to recover energy, there is a need to use engine over run to recover energy, unfortunately the 'jerks' that occur during downshifting tend to upset the rear of the car and the control problems balancing the rear braking to the front at the same time as harvesting energy from a generator on the crank working in steps over a wide rpm range is very difficult.
At the same time the engine is being used to burn fuel on over run to expel high mass exhaut gas flow over the outer 50mm of the rear diffuser lip to increase downforce. (or over the top and bottom front undertray lip on the Renault).
The problems with KERS that RB have, is a direct result of designing a car for aero and only giving enough space for a KERS unit of reduced size
and without sufficient cooling.
The regulation changes banning 'blowing' rear diffusers is at least partly because of this, so as to push development away from pointless and hugely expensive aero and back on track and into ongoing KERS development which is the future for both racing and road use.

[cheapracer]

Most "classical" race cars don't have an electronically controlled dynamic brake balance setup.

Using the engine to balance brake distribution between front and rear is a widespread and accepted technique in my book.

No but they certainly have diffs, brake bias systems, adjustable dampers, front and rear springs and pump up tyres.

And 99% of people will agree with you.

[WhizzMan]

No but they certainly have diffs, brake bias systems, adjustable dampers, front and rear springs and pump up tyres.

And 99% of people will agree with you.

You can't really go out and change your tire pressure, damper adjustment or brake bias in the middle of braking at the end of the straight, can you? Those are adjustable, but the dynamic balance while your are in the middle of it, comes from how much you brake, engine brake you apply and how much you pre-steer. Yes, you can twist the knob on your brake bias if the overall balance should be more to the front or the rear in the car, but that's not the point of my reaction. Making use of every bit of grip the car has at that moment requires "manual" adjustments to brake pedal, throttle, and steering wheel. If you had EBD and ESP on the car, the computer would just brake each wheel and you could count on the almost perfect stop every consecutive time. Honda appears to have made a brake system that is able to continuously out-brake every human that tried every time, so in the future, we will see people with that system on their car be "unbeatable" at braking.

24garrard: You sound like a sales man when I ask for details. Everyone claims their system is better, please put some facts and figures behind it to back up your claims.

20 kilos total sounds rather light, considering the fact that you need either permanent magnets or electromagnets on the rotating part to do anything KERS related. I doubt you'd be able to build a generator/starter motor grade setup with less than 5-7 kilos added weight to the gear box. Let's, for the sake of argument, not count that, because a normal setup has a generator with that weight as well. If you want the vehicle to have any acceleration benefit from it at all, you'd be looking at having to provide at least 10 times as much torque. How will you do that with a total weight of 20 kilos for the system and the gears? I know Honda has removed the normal fly wheel and used their hybrid system for that, but still, how about some facts and numbers of your solution so we can see just how great it is?

What efficiency will your system have when not in direct through configuration? Most vehicles don't spend all their running time in top gear.

How would you drive in traffic jams if there is no hybrid drive used and without a clutch? Is hybrid setup mandatory?

Again, what will a battery and generator/motor weigh on a motorcycle? My Kawasaki ZXR400SP needs clutch up to 50 km/h in first gear, just to get it to move, being a 400cc racing bike. When driven in anger, clutch is slipped up to 70 km/h. How would you make that bike accelerate with it's stock 6Ah battery? Don't say my gear ratio's are all wrong. This is a racing engine that has a power band between 11000 and 14000 rpm and you'll want all gears available in the speed range where you drive the bike on track. You'd be competing with well over 40 kW engine force when using a conventional system with a clutch.

[24gerrard]

Hi WizzMan
Yes, the sales pitch is there I agree.
I am retired (most of the time) and I no longer travel the world on such projects.
However old associates keep pushing me to promote it, so why not.
It is early days and I am not prepared to quote any figures yet.
There is university working with me to establish a doctorate with commercial matched funding at present.
I can only say that a number of F1 teams and other top engineers have had sight of the system and they all agree.
At the least an in depth feasibility study should be undertaken.
I have a lunch on the subject today.

In each mechanical gear ratio, the system uses only one planetary set, the others are locked.
Torque loss is therefore just that one epicyclic and the one single shaft support bearing.
The input is supported directly in the crankshaft. (no clutch)

Yes, there needs at least to be a larger battery for at least a 'part' hybrid use, for initial drive forwards or reverse to establish vehicle inertia electricaly.
(bike forward only)
This battery system also needs to supply current for gearshifts.
The 'conventional' application is more suited for heavy long haul vehicles.
The ic engine can even be off during this initial drive.

Because the vehicle drives away electricaly (FIA F1 regulation soon for paddock use), the ic engine is not used for traction until a certain 'speed' is achieved, therefore the gear ratios can be different to account for engine rpm/cam needs.
In your case, the first ratio would be low enough to achieve your 11000 rpm with the already rotating output shaft before electro magnetic engagement.
This gear engagement, induction faze also gives a CV (shift) both on initial engagement and during up and down stepped shifts.
In your case this could be 'modulated in first engage to replace clutch slip.

Not sure if I attempted all your questions, I am a bit busy today.
However, I am sorry no figures yet but I will try to answer anything else.

On this thread about manual gear shifting of a layshaft gearbox, you can make a good comparison with the manual shift,
the semi/full auto layshaft shift and my ESERU with a constantly variable electro magnetic shift. (fully stepped mechanical gbox)
(not to be confused with any torque sapping CVT/Hybrid complete transmission such as the Honda Prius, which has two electric motors and an ic engine fighting each other through an epicyclic)

Edited by 24gerrard, 16 June 2011 - 09:42.