New MHEV 500 & Panda

[portland_bill]

I wonder if this has anything to do with the PSA merger...as what you've described there is literally the system from my wifes old DS3 circa 2014.

In the PSA system at the time you had a standard battery with separate lithium capacitor on the top.

If it is this system then the good news is it actually works because the main battery voltage has nothing to do with stop start activation (unlike the previous Fiat effort). The bad news being it is nothing everyone else isn't already doing and has been doing for years.

It also made no difference to the economy of the car it was fitted to iirc a 1.6 diesel that managed to produce 1mpg better economy than the petrol that replaced it. The petrol also has a similar system with the capacitor but they do not call it a mild hybrid because it doesn't have the reversible alternator.

The system I saw details of recently had the motor/generator installed within the gearbox casing. The fiat website gives little detail, but does suggest energy recovery happens while coasting, which needs the generator to be connected to the wheels, not the engine, suggesting their system is at the gearbox, not at the normal alternator position.

Of course, their definition of coasting might be different to ours. To me it is when the car is out of gear, or clutch down, so gearbox is disconnected from the engine. Difficult to see how an engine connected alternator will give anything in those conditions.

 

[StevenRB45]

The system I saw details of recently had the motor/generator installed within the gearbox casing. The fiat website gives little detail, but does suggest energy recovery happens while coasting, which needs the generator to be connected to the wheels, not the engine, suggesting their system is at the gearbox, not at the normal alternator position.

Of course, their definition of coasting might be different to ours. To me it is when the car is out of gear, or clutch down, so gearbox is disconnected from the engine. Difficult to see how an engine connected alternator will give anything in those conditions.

On the PSA system (given this technology has magically appeared so far into the 500s life I think it's reasonable assumption they are related) coasting was travelling foot off the accelerator clutch up and in gear.

When doing this the alternator charged at an extremely high rate compared to standard into the capacitor, it was also used to start the engine for stop start rather than the starter motor. It may well be they've uprated it a little to provide a power boost not just start the engine.

Reading the review they even share the same ability to "eco roll" as the old E-HDI. I.e. if you're arriving at a set of lights or travelling down hill if you hit neutral and release the clutch it'll activate stop start at speeds less than 20mph (yes this is awful driving practice).

 

[AndyRKett]

The system I saw details of recently had the motor/generator installed within the gearbox casing. The fiat website gives little detail, but does suggest energy recovery happens while coasting, which needs the generator to be connected to the wheels, not the engine, suggesting their system is at the gearbox, not at the normal alternator position.

Of course, their definition of coasting might be different to ours. To me it is when the car is out of gear, or clutch down, so gearbox is disconnected from the engine. Difficult to see how an engine connected alternator will give anything in those conditions.

So the fiat system uses a reversible alternator and if you find pictures specifically of the engine there is a pretty hefty pulley system around the alternator mounted on the front of the engine above the aircon compressor, to tension the belts. When rolling at speed the alternator becomes a generator, right down to the point the car stops. With the system if you coast out of gear then it will stop the engine at slower speeds, then restart the engine if you put the clutch in to select a gear.

The system specifically stops the engine when doing what we were all taught not to do, coast out of gear. So no engine braking, extra stress on the clutch if you Re-select a gear without coming to stop.

There are other engineering questions, such as if you where coasting down a hill with the engine stopped, all the coolant in the radiator is not being circulated and will get cold, the coolant in the engine will likely increase in temp as the heat from the metal makes its way into the coolant, then the engine restarts pushing cold coolant through a hot engine.

As stated the 53mpg figure isn’t even that good

 

[AndyRKett]

I should point out the Bluemotion tech in my golf will charge the battery of the car at a high rate when coasting in gear, then will freewheel/idle when accelerating. This massively reduces the loads on the engine when under power. They also fit higher ratio gears to blue motion cars, improve aerodynamics and other tweeks which have a better fuel saving to compatible non bluemotion cars, than the 2-3% supposed improvement of the mild hybrid set up.

 

[StevenRB45]

My feeling would be they've dived into the PSA parts bin and done what they can to reduce CO2 until they can get a CMP all electric car out of the door.

There are other engineering questions, such as if you where coasting down a hill with the engine stopped, all the coolant in the radiator is not being circulated and will get cold, the coolant in the engine will likely increase in temp as the heat from the metal makes its way into the coolant, then the engine restarts pushing cold coolant through a hot engine.

The E-hdi used an electric water pump to cool both the engine and turbo that ran independently of the engine itself, whether that is true in this case we'll find out. It also ran the steering off the capacitor and monitored vacuum so the engine restarted before you lost brakes.

 

[AndyRKett]

The E-hdi used an electric water pump to cool both the engine and turbo that ran independently of the engine itself, whether that is true in this case we'll find out. It also ran the steering off the capacitor and monitored vacuum so the engine restarted before you lost brakes.

Its all potentially more complicated than what it replaces, which as fiat proved with the multiair system, they don't do complicated very well.

Where fiat always did best was with simple engineering.

 

[varesecrazy]

A bit of 'e.stern promise'

https://fleetworld.co.uk/fiats-first-electrified-models-pave-way-for-fully-electric-500e/


I found this while looking for the article I read lately of the 80's and 90's euro citycars on battery power

The cinq had the same range as the modern stuff ( 60 miles on lead acid.. 110 on the optional NiCad)
It had regenerative braking.. and an electronic display
Panda that followed it had better specs

25 years ago..
Then they realised battery tech was limiting.. so went Hydrogen

 

[StevenRB45]

Its all potentially more complicated than what it replaces, which as fiat proved with the multiair system, they don't do complicated very well.

Where fiat always did best was with simple engineering.

If it is a relative of the old E-HDI then it's a well proven system having been around for 10 years or at least it lasted longer than absolute boat anchor of diesel engine it came with. Which given they fairly regularly lunch themselves with less than 80k on isn't a high bar admittedly.

 

[AndyRKett]

If it is a relative of the old E-HDI then it's a well proven system having been around for 10 years or at least it lasted longer than absolute boat anchor of diesel engine it came with. Which given they fairly regularly lunch themselves with less than 80k on isn't a high bar admittedly.

I doubt this new system in the fiat has anything to do with PSA. Given how soon after the merger this is being launched the likelihood is that the car was already completing development by the time the merger took place

 

[StevenRB45]

I doubt this new system in the fiat has anything to do with PSA. Given how soon after the merger this is being launched the likelihood is that the car was already completing development by the time the merger took place

Do you not think it slightly odd that somehow they've arrived at a system with the same capability PSA has been using for 10 years that is mainly bolt on bits?

 

[portland_bill]

Do you not think it slightly odd that somehow they've arrived at a system with the same capability PSA has been using for 10 years that is mainly bolt on bits?

These systems are mostly developed by outside suppliers, such as Continental, Bosch, etc. Then adapted for individual vehicles, so whilst likely to be similar to PSA stuff, is also likely to have been on the cards before the merger.

 

[AndyRKett]

I remember reading about this type is system about 10 or so years ago and I think the article I was reading was a Bosch system.