HOW TO USE correctly OR SHIFT B GEARS FOR FUEL ECONOMY

[maby]

Many, is there, in your opinion, a CVT between the battery and the wheels, which is used in EV mode?

Not between the battery and the wheels, no. The battery feeds in part way through the transmission chain - the CVT exists between the petrol engine and the wheels and there is no single component that you can point at and say "here's the CVT".

I hope we can agree that, in serial hybrid mode mode, power coming from the generator is fed 'into the transmission' the same way and at the same point, as power coming from the battery in EV mode. Then consequently, there is also no CVT between the generator and the wheels. And then, if you are right, the generator would have to be the CVT.

The CVT is implemented in the firmware which adjusts the power flow through the drive train to match the power output of the engine to the power demanded at the wheels. If I let my battery go flat and then accelerate away from stationary to the high end of the serial mode range - around 45mph - the engine speed will be relatively independent of road speed, but will vary dramatically in response to demand for acceleration - exactly the way an old DAF would behave under similar patterns of usage. That is CVT - electric CVT, not mechanical CVT, but CVT all the same. There are big construction plant machines that use hydraulic CVT - again the same effect, but any mechanical gearboxes in the drive train are fixed ratio - that does not automatically mean that they are not CVT!

 

[anko]

The CVT is implemented in the firmware which adjusts the power flow through the drive train to match the power output of the engine to the power demanded at the wheels. If I let my battery go flat and then accelerate away from stationary to the high end of the serial mode range - around 45mph - the engine speed will be relatively independent of road speed, but will vary dramatically in response to demand for acceleration - exactly the way an old DAF would behave under similar patterns of usage. That is CVT - electric CVT, not mechanical CVT, but CVT all the same. There are big construction plant machines that use hydraulic CVT - again the same effect, but any mechanical gearboxes in the drive train are fixed ratio - that does not automatically mean that they are not CVT!

How does one 'adjust the power flow through the drive train'? I thought that 'what comes in must come out'? Not much adjustment going on there. Or is this going in a direction where we say 'the variable part is of the transmission is the battery that can act as a buffer between power demand and power supply'?

 

[Claymore]

You are of course correct jaapv (it was late and I was getting fed up) and in being so reminded me of one of the more infuriating things about this forum, namely that the same questions will get asked repeatedly by the stream of 'newbies' (and I certainly took my turn) but on subjects such as this why are there not more 'stickies' posted at the head of appropriate sections of the forums so that the usual stalwarts don't have to keep stating the same things over and over again?

If the sticky was locked and only capable of alteration by an administrator others would be free to offer thoughts by PM if something obvious (and actually useful and/or pertinent might be added or changed) or if the passing of time required some or all of it to be 'refreshed'.

JimB

 

[maby]

The CVT is implemented in the firmware which adjusts the power flow through the drive train to match the power output of the engine to the power demanded at the wheels. If I let my battery go flat and then accelerate away from stationary to the high end of the serial mode range - around 45mph - the engine speed will be relatively independent of road speed, but will vary dramatically in response to demand for acceleration - exactly the way an old DAF would behave under similar patterns of usage. That is CVT - electric CVT, not mechanical CVT, but CVT all the same. There are big construction plant machines that use hydraulic CVT - again the same effect, but any mechanical gearboxes in the drive train are fixed ratio - that does not automatically mean that they are not CVT!

How does one 'adjust the power flow through the drive train'? I thought that 'what comes in must come out'? Not much adjustment going on there. Or is this going in a direction where we say 'the variable part is of the transmission is the battery that can act as a buffer between power demand and power supply'?

The buffer functionality of the battery is certainly an important enabler - without it the process would be less efficient. But it is not the only factor - your own argument for letting the battery run down is based on the principle that the amount of power you can draw from the engine is not inextricably linked to the RPM.

You simply have to get away from this idea that CVT implies any particular implementation - it's a concept that can be implemented in a variety of ways - though not all of them would make any practical sense. I could couple the output of the ICE to a variable pitch propeller in a tube blowing air over another propeller coupled to the wheels - that would make a CVT - probably very inefficient, but a CVT all the same.

 

[Carnut]

Jaapv said :[/quote]In tht case there are but two possibilities: the person you were talking to hadn't the faintest idea or they were pulling your leg. As for qualifications, I think a BSc. in mechanical engineering from Delft Technical University counts...
[/quote]

I think your comment above is ridiculous in the extreme. Do you REALLY think that the technical team in Mitsubishi UK 'don't know what they are talking about" or "They were pulling your leg"
You don'r SERIOUSLY think either is likely?????? (or are you now pulling my leg. in which case HA-HA, very funny. :lol: :lol: :lol: )
I concede that your Qualifications exceed mine.

 

[maby]

Jaapv said

In tht case there are but two possibilities: the person you were talking to hadn't the faintest idea or they were pulling your leg. As for qualifications, I think a BSc. in mechanical engineering from Delft Technical University counts...

I think your comment above is ridiculous in the extreme. Do you REALLY think that the technical team in Mitsubishi UK 'don't know what they are talking about" or "They were pulling your leg"
You don'r SERIOUSLY think either is likely?????? (or are you now pulling my leg. in which case HA-HA, very funny. :lol: :lol: :lol: )
I concede that your Qualifications exceed mine.

He should be a bit careful about waving certificates around in here - he's certainly not the only one with a BSc in engineering. Admittedly, mine is in Electrical Engineering, but we had to do course units in mechanical engineering too. And I'm also a trained turner and miller - there was a time when I could have built you a four speed synchromesh gearbox by hand from steel stock given access to a decent milling machine and lathe. And I do mean "by hand" - there were none of these Nancy-boy CNC machines around forty years ago when I was building turbine shafts from stock steel bar!

 

[HHL]

the principle that the amount of power you can draw from the engine is not inextricably linked to the RPM.

You simply have to get away from this idea that CVT implies any particular implementation - it's a concept that can be implemented in a variety of ways - though not all of them would make any practical sense. I could couple the output of the ICE to a variable pitch propeller in a tube blowing air over another propeller coupled to the wheels - that would make a CVT - probably very inefficient, but a CVT all the same.

Well... the amount of power you get out of an engine is a direct function of torque and rpm... So they are very much linked.
As for you propeller idea... that is not analogue to a CVT, it is a torque convertor pure and simple, if you adjust the pitch, you'll vary the coupling but never the ratio.

 

[Claymore]

....As for you propeller idea... that is not analogue to a CVT, it is a torque convertor pure and simple, if you adjust the pitch, you'll vary the coupling but never the ratio.

That is why, many posts back my ignored analogy developed that to a constant speed unit where the propeller rpm is maintained constant by the unit (within limits) and it does that by changing the pitch of the propeller blades ie if you reduce throttle the CSU moves the blades to a finer pitch to maintain the preselected rpm and so on.

I thought that might be a CVT example.

JimB

 

[Carnut]

And so it goes on & on & on ad infinitum!
Somebody please lock this thread before my brain explodes! :lol:

 

[jaapv]

Jaapv said :

In tht case there are but two possibilities: the person you were talking to hadn't the faintest idea or they were pulling your leg. As for qualifications, I think a BSc. in mechanical engineering from Delft Technical University counts...
[/quote]

I think your comment above is ridiculous in the extreme. Do you REALLY think that the technical team in Mitsubishi UK 'don't know what they are talking about" or "They were pulling your leg"
You don'r SERIOUSLY think either is likely?????? (or are you now pulling my leg. in which case HA-HA, very funny. :lol: :lol: :lol: )
I concede that your Qualifications exceed mine.

Yes I do think you were misinformed.
As for the qualification I made an educational U-turn afterwards It is just that you asked

 

[Carnut]

Well, if you are determined to continue misbelieving the manufacturer, may I suggest you ring them up, discuss it with them and then we shall all be enlighted. 'Phone number on www.mitsubishi-cars.co.uk
Until them I can see absolutely no reason to believe your take on the situation over Mitsubishi's.
You are , I am sure avery able engineer, but unless you actually had a hand in designing the car, or have dismantled one, I fail to understand how you can continue with your dogmatic attitude..??

 

[anko]

Well, if you are determined to continue misbelieving the manufacturer, may I suggest you ring them up, discuss it with them and then we shall all be enlighted. 'Phone number on http://www.mitsubishi-cars.co.uk
Until them I can see absolutely no reason to believe your take on the situation over Mitsubishi's.
You are , I am sure avery able engineer, but unless you actually had a hand in designing the car, or have dismantled one, I fail to understand how you can continue with your dogmatic attitude..??

No need to dismantel anything, Carnut. On this forum, there is no dispute on what can be found inside that car and what not. The dispute is on whether or not the things that can be found in the car qualify as a CVT or not. So, the discussion is not PHEV or Mitsubishi specific and a Mitsubishi representative is not by definition more authoritative than the next guy.

For one thing, we all agree that what can be found in the car does not qualify as a CVT gearbox ;-)

 

[anko]

Maby,

I have a small confession to make: I Googled "hydrostatic CVT". I was expecting to find something like a hydraulic torque convertor (as you find them in cars with traditional automatic gearboxes), where a rotational force is transformed directly into another rotational force, by means of more or less rotational flow of hydraulic fluid. Instead, I found pictures where an hydrostatic pump transforms a rotational force into a lineair flow of a fluid, which in turn is converted into a rotational force by a hydrostatic pump:

Seeing this, I can now imagine why you would want to refer to the drive train architecture of the PHEV as a CVT: the generator would take the place of the hydrostatic pump and the e-motor(s) would take the place of the hydrostatic motors. And the electrical wiring would take the place of the pressure lines.

Of course, and to nobody's surprise as I am still me :lol: , having seen this I still wouldn't refer to the PHEV architecture as being a CVT for a few reasons:

- People will mistakenly misinterpret it as 'having a CVT gearbox', whether we like it or not.

- Unlike with a hydrostatic (or other type) of CVT, we find several other components hooked up in between the 'pump' and 'motor', such as a heater, a battery, a charger, etc., allowing the 'pump' and 'motor' to be fully functional independent of each another. Where the hydrostatic pump and the hydrostatic motor of the hydrostatic CVT IMHO cannot function independent of each other. Imagine a circular high pressure line with two or three pumps (one of which acts as a motor too) mounted onto it / into it, at least two motors (both of which act as a pump as well), a device that transforms hydraulic pressure into heat, and a pressure vessel to buffer some of the hydraulic pressure 'for later use'. Would you still call that a CVT? Where it is so much more? Let me swing that around: if there had been a straight through electrical power line from the generator to the two e-motors, without any other devices attached to it (battery, heater, OnBoard Charger, ChaDeMo port, etc.), then I would probably have said the PHEV has a CVT

 

[maby]

Maby,

I have a small confession to make: I Googled "hydrostatic CVT". I was expecting to find something like a hydraulic torque convertor (as you find them in cars with traditional automatic gearboxes), where a rotational force is transformed directly into another rotational force, by means of more or less rotational flow of hydraulic fluid. Instead, I found pictures where an hydrostatic pump transforms a rotational force into a lineair flow of a fluid, which in turn is converted into a rotational force by a hydrostatic pump:
...

At last, we are on the same page! My problem has always been that you, and Jaap, have insisted on describing the PHEV as "having a CVT effect" or words to that style - CVT is an effect. There are many ways to achieve it - some are practical and others are purely of academic interest!

 

[greendwarf]

I think your comment above is ridiculous in the extreme. Do you REALLY think that the technical team in Mitsubishi UK 'don't know what they are talking about" or "They were pulling your leg"
You don'r SERIOUSLY think either is likely?????? (or are you now pulling my leg. in which case HA-HA, very funny. :lol: :lol: :lol: )

Well I do for a start - you have no idea who spoke to who, only what the girl told you - she could have got the info from the car wash guy, for all we know. Remember Colt Cars UK are an importer NOT the manufacturer, who have a franchise to SELL Mitsu cars. I doubt she rang Japan :lol:

 

[ian4x4]

I too have Googled CVT of all types.

I believe the Outlander PHEV qualifies as a heavily buffered CVT once the battery is run down sufficiently to play little part in the energy supply.

I think of it similar to a Hydrostatic CVT, where the motor drives a pump (generator), to supply a reservoir (battery), which drives a motor giving propulsion.

I blame computers, in the old days, all kinds of drive mechanisms were used with gears, differentials, balls, etc, etc.
You needed a lot of (longhand) maths, but the answer was always obvious.

With computing I soon learnt that when something went in, what came out wasn't that obvious, and could be readily changed.

The Outlander PHEV is a very simple machine, with a very complicated control system. You could argue forever, but it works.

 

[Neverfuel]

If we lose the power source(s) from the argument so that we can't claim that the battery or engine is part of the equation, then having read and understood both sides of the argument(s) - can someone explain or argue the fact for CVT, when:

- the front axle is ALWAYS connected to the front motor through 3 permanent fixed reduction gears.
- the rear axle is ALWAYS connected to the rear motor through 3 permanent fixed reduction gears (different value to the front reduction gears due to different motor type).
- the generator is SOMETIMES (depending on mode) connected through a fixed reduction gearing system to the road wheels through a wet clutch, but is ALWAYS connected to the engine as it also acts as a starter.
- the engine powers the road wheels DIRECTLY (in parallel mode) through a single gear, giving linear acceleration/RPM.

But please, don't use analogies like prop feathering (remember I am a pilot), show me in a diagram if necessary, how the TRANSMISSION (not the power unit) could possibly be VARIABLE when it has fixed ratio gears in the front & rear motor transaxles and wet clutch mechanisms to take up the load.

If anyone is implying that a wet (or otherwise type of) clutch gives the "effect of a CVT", and applying that mentality to the PHEV, OR battery storage forms a part of the overall TRANSMISSION system, then the lines are getting too blurred.

Think of the problem like this:

If a conventional car engine fails - how do you make the vehicle easier to push by hand?

If the PHEV was 0% SOC AND engine failed - what could you do that would be similar, BUT more importantly, what would you need to do that would be DIFFERENT?

Here endeth yet another lesson!

Good night most, good morning AUS!

 

[anko]

- can someone explain or argue the fact for CVT, when: ...

Hi Neverfuel,

(between you and me, here it is ):

It could be a CVT when you don't look at the E-motor as a motor and you don't look at the generator as a generator. Instead, see both as components of the CVT itself. Put them in a black box together. Then that box has the engine drive shaft as an incoming axle and the axle(s) of the car as outgoing axle(s). And indeed, then RPM of the incoming axle is independent from the RPM of the outgoing axle(s).

For sure, that black box provides a CVT effect and if there was nothing more to the box, I would even call it a CVT. Don't forget, even within a CVT there may be some fixed gearing going on, next to the variable gearing. But there is much more connected to the box (heating, cooling, buffering, grid charging, regenning, and what not). For this reason, I see it as 'a bunch of components providing a CVT effect'.

Maby states that the acronym 'CVT' by itself refers not to a device, but to a particular effect. An effect that is undeniably present in the PHEV, so he insist in saying the PHEV has a CVT. Although in an academic world he might even be right, I am afraid that in the real world (and on this forum) most people don't see it this way, leading to the same discussion over and over again.

I would be very happy if, on this forum, we could agree to talk about a "CVT gearbox" when referring to a device and about "CVT effect" when referring to the fact the engine RPM can fluctuate independently of wheel speed in an infinitive number of ways. And when we can agree not to refer to "CVT" without clarifying whether we are referring to a device or an effect. This will save us from a lot of rather insignificant discussions in the future.

From the beginning, we said that the discussion applied to a PHEV in serial hybrid mode only. With all that has been said can now wonder if that must be. Modern CVT gearboxes have a number of fixed gear ratios programmed into them. From a functional perspective, you could easily compare the parallel drive mode of the PHEV to a (the only) pre-programmed fixed gear ratio of a CVT gearbox.

 

[maby]

Good grief! We are in agreement at last!

The PHEV has a Continuously Variable Transmission that is not implemented as a gearbox.

You do realise that a lot of this almost interminable discussion is the fault of the Americans and their corruption of the English language? When I was a young engineer, we would never have described the thing that typically sits somewhere between the driver and passenger, coupling the engine to the wheels, as the transmission. It was the gearbox - and its purpose was to implement the transmission function between the engine and the road wheels. So, it's really all the fault of the yanks and their sloppy use of English. (And there are no yanks on this forum as far as I know, so we can safely criticise them as much as we want! )

 

[anjuhiru]

so ok friends....can anybody here summaries the best economical way to use B paddles ???? specially battery charge finish fully and need to run in petrol engine????