Advances in Car Technology (Part 2)

Ok we have one - here's an opportunity to have one - if you got a point of view about something and want to share it - here's where you do it.
Chas
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Advances in Car Technology (Part 2)

Post by Chas » Sat May 19, 2012 4:48 pm

My last thread was meant to be a serious effort to understand what has changed so much in the last, say, 20 years in terms of automotive efficiency, specifically with petrol-fuelled cars. Instead, I went off on one about the merits - or lack of them - of a Bluemotion Jetta :roll: Sorry!

What I was looking for was a more engineering-based discussion on what has contributed to the massive increases in economy, especially with bigger-engined vehicles, since I started my driving career. In those days, a Lamborghini could average 15mpg on a good day with a tail wind. Today, a Lambo is twice as fast and yet twice as efficient.

My pre-20s weekends were mostly spent under the bonnet of my MkII Escort 1.3, trying desperately to make it perform more like an RS2000 whilst also trying to improve its measly economy. My motiviation didn't diminish when I moved up to an Opel Manta 2.0 but in those days I could fill my tank for a tenner.

So, given that the basics of the internal combustion engine haven't changed - a fuel/air mix burining in cylinders driving pistons to turn a crankshaft - what are the key changes that have increased both specific output and efficiency in todays vehicles?

Hypothetically, which of these improvements could be retrofitted to, say, an M30 engined 7-series in order to improve performance and economy?

Discuss... :lol:

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Post by ade and liz flint » Sat May 19, 2012 6:06 pm

Top of the head:-

High pressure fuel lines
Highly accurate piezo injectprs
Closer build tolerances
'Clever' low friction coatings
Lighter materials (Engine and chassis/body)
Higher thermal efficency
Thinner lube oil
Brake regeneration
Low-loss bearings
Start/stop tech
Stick a motor in the drive-train

Bound to be lots more :D ...but can't see any as a retrofit for your 7er :twisted:
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Post by joylove » Sat May 19, 2012 9:55 pm

Good list from Ade (or Liz!) there.

A couple of the big hitters

Tolerances. Improving them allows a better quality control and less margins between units.

Multiple valves. 4 Valves per cylinder with variable timing.

Direct injection. More repeatable pressure between cylinders.

Valvetronic. The fueling is controlled by the piezo injectors and the throttle body is left wide open reducing pumping losses.

Ion monitoring. In the M cars they can use the spark to monitor for knock allowing them to rev higher.

Better ECUs and understanding. More processing power and more experience in mapping helps make things better.

Spark plug technology and gapping. More repeatability between cylinders and over time meaning less margins between units.





Really the diesel has seen many more advances because they sell so many units compared to petrol, and the forced induction and high pressure and direct injection systems can be advanced for significant gains, but bring along the associated problems of reliability and cost of parts found in new technology.

We may see the R&D budget switch to petrol turbos to meet new emissions regs, and also the return to miller cycle and leanburn cycle for modern hybrids where the engine does not directly drive the gearbox and wheels and can run at fixed RPM and timing, with shaped piston heads and flame fronts and tuned inlet and outlet manifolds.

Another thing I was looking at 12 years ago in Uni was neural net timing. The knock sensor, by ion or by piezo ear, works on an "after the spark" system, always one revolution behind, meaning the timing must never be perfect in case a sudden change in load causes hugely damaging detonation. Combined with a capacitive (rather than traditional inductive) discharge, the ion monitoring system can recognise the drop in resistance as the fuel/air mix is just about to detonate, and the spark timing and duration can be adjusted before the knock occurs. This means you can have perfect timing for every burn with little-to-no safety backoff.

Finally, there has been talk of improving petrol engines to the point where they can actually run like a diesel, without a spark, not entirely sure of the benefit, presumably releasing all the energy in a much faster and hotter and therefore environmentally cleaner burn.
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Post by ade and liz flint » Mon May 21, 2012 8:53 am

Bumped into this BBC website article wiith their take on the paths the various major manufacturers are taking on the subject of low capacity/high performance(ish) new petrol engines.

Interesting just how many differing routes are being taken to achieve the same basic result. Fiat's TwinAir is, I understand, slightly overstated in that its performance is woeful, and the fuel returns are nowhere near those claimed by Fiat, and it will be interesting to see how Ford (and indeed BMW) have/will overcome the inherent noise/vibration and harshness of a 3-pot internal combustion engine and make it attractive to the masses.
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Post by Chas » Mon May 21, 2012 9:15 am

ade and liz flint wrote:Bumped into this BBC website article wiith their take on the paths the various major manufacturers are taking on the subject of low capacity/high performance(ish) new petrol engines.
Interesting article. One thing that is very apparent with the oil-burning Jetta I have on loan is that it doesn't reach operating temperature before I reach my destination (even though it still achieves 60+mpg getting there!) It stands to reason that a modern diesel is more suited to long journeys / high mileages and a small petrol car will be better for short commutes of less than 30 minutes.

All of my fleet are clearly best kept in the garage and I should use the lawn mower to commute :oops:

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Post by ade and liz flint » Mon May 21, 2012 9:47 am

Chas wrote:One thing that is very apparent with the oil-burning Jetta I have on loan is that it doesn't reach operating temperature before I reach my destination (even though it still achieves 60+mpg getting there!) It stands to reason that a modern diesel is more suited to long journeys / high mileages and a small petrol car will be better for short commutes of less than 30 minutes.
That's interesting - how long is the journey? The D3BT reaches operating temperature very quickly, indeed (it's something BMW worked very hard to achieve with some clever tech). I can watch the engine coolant temperature digitally on the steering wheel on mine and it increases at a staggering rate for a derv. They started this with my late E46 M47TUD engine, which had 'special' cooling vanes on the radiator and another couple of tricks, and have developed this much further on the N47, now.

Oh, I should add that conversely to this, the Astra derv takes an eternity to get off cold...which will be a wake-up call next winter and beyond :shock: :lol: It is a perfect example of diesel development over 10 years...both 2litre, one 99bhp, the other 214bhp, the Astra derv will rev, strangely, similar to the BT, both return 45mpg(ish), Astra is a soot-blower, BT is not and a sundial can be used to measure the Astra turbo-lag, the BT has none :lol:
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Post by Chas » Mon May 21, 2012 10:34 am

ade and liz flint wrote:That's interesting - how long is the journey?
It's 13 miles and takes 20 minutes if I leave before 7am. I should clarify that I'm talking about oil temperature, not water temperature. The Jetta has a digital oil temp gauge and an old-fashioned dial for water temp. Having said that, the water temp doesn't reach the centre of the dial until about 10 miles / 15 minutes of A road driving.

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Post by vblanche » Mon May 21, 2012 12:15 pm

Maybe I'm hihjacking this thread (if so, please move my psot): can someone explain me the start/stop system? I mean, is it more or less a pollution factor?
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Post by Chas » Mon May 21, 2012 12:30 pm

vblanche wrote:can someone explain me the start/stop system?
It's very simple... The car will turn off the engine when it assumes you are in stationary traffic - neutral gear and foot on the brake. As soon as you depress the clutch to engage first gear, the engine starts again. It's designed to save fuel on the Urban cycle but it means your starter motor will suffer excessive wear instead so the monetary gains will be wiped out in due course :?

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Post by Broch » Mon May 21, 2012 12:48 pm

vblanche wrote:Maybe I'm hihjacking this thread (if so, please move my psot): can someone explain me the start/stop system? I mean, is it more or less a pollution factor?
With the 8-speed box, just coming to a stop with your foot on the brake, causes the engine to cut out. Before I can put my foot back on the go peddle, the engine has started.
This can of course be 'switched' off with the press of a button 8)
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Post by ade and liz flint » Mon May 21, 2012 12:58 pm

Chas wrote:
ade and liz flint wrote:That's interesting - how long is the journey?
It's 13 miles and takes 20 minutes if I leave before 7am. I should clarify that I'm talking about oil temperature, not water temperature. The Jetta has a digital oil temp gauge and an old-fashioned dial for water temp. Having said that, the water temp doesn't reach the centre of the dial until about 10 miles / 15 minutes of A road driving.
The BT is at operating temp within 4 miles of leaving home. That's water, not oil temp obviously, and I would expect the oil to get up to temp quicker than the water as the water is effectively cooling the oil and taking-on those heat losses generated in both lubricating and cooling the engine. Hmm, I'd like to see the heating curves, now...interesting.

My understanding on stop/start equipped cars is that they have an uprated high load starter motor. Mine is alwyas activated, but as it does very few stop/start journeys is only rarely used.
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Post by E24man » Mon May 21, 2012 1:17 pm

ade and liz flint wrote: The BT is at operating temp within 4 miles of leaving home. That's water, not oil temp obviously, and I would expect the oil to get up to temp quicker than the water as the water is effectively cooling the oil and taking-on those heat losses generated in both lubricating and cooling the engine. Hmm, I'd like to see the heating curves, now...interesting.
:no (always wanted to use that emoticon :D )

Having owned an E34 M5 Touring (which has an oil temp gauge where the standard econometer was) and now the Alpina B10 4.6 which has oil temp, oil pressure and gearbox temp gauges I can confirm that the oil will always take longer than the water to get up to normal operating temperature which is approximately 85-90 degrees C.; up to 100 degrees when really pushed hard.

The diff temp also is unusual in that stays relatively cool unless worked hard; frequent speed changes will heat it up more than a sustained motorway speed when I suspect the cooling fins have a far greater effect.

The engine oil always takes a good ten minutes driving before getting close to the 80 degree range and this about twice as long as coolant temperature.

I'm sure if I rattled my brains long enough the specific thermodynamic properties of the coolant and engine oil would explain why things are this way round.

The oil temp in the B10 4.6 is generally in the range I said above, and the highest I have seen is only 93 I think; the diff temps generally run around 40 degrees when pootling about, 65 to 70 on a motorway and up to about 80 when pressing on with frequent sudden speed changes.

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Post by Chas » Mon May 21, 2012 1:47 pm

ade and liz flint wrote:I would expect the oil to get up to temp quicker than the water
I would have expected the same, especially since the specific heat capacity of water is 4.2 against oil of around 2. However, I've noticed this will all cars having both oil and water temperature gauges. The E34 M5 and B10 BT both took far longer to get their oil up to temperature.

I've made the point before that people shouldn't assume they can give their car the beans just because the water is up to temperature because the oil may only just getting warm :shock:

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Post by ade and liz flint » Mon May 21, 2012 1:51 pm

E24man wrote: :no (always wanted to use that emoticon :D )

Having owned an E34 M5 Touring (which has an oil temp gauge where the standard econometer was) and now the Alpina B10 4.6 which has oil temp, oil pressure and gearbox temp gauges I can confirm that the oil will always take longer than the water to get up to normal operating temperature which is approximately 85-90 degrees C.; up to 100 degrees when really pushed hard.

The diff temp also is unusual in that stays relatively cool unless worked hard; frequent speed changes will heat it up more than a sustained motorway speed when I suspect the cooling fins have a far greater effect.

The engine oil always takes a good ten minutes driving before getting close to the 80 degree range and this about twice as long as coolant temperature.

I'm sure if I rattled my brains long enough the specific thermodynamic properties of the coolant and engine oil would explain why things are this way round.

The oil temp in the B10 4.6 is generally in the range I said above, and the highest I have seen is only 93 I think; the diff temps generally run around 40 degrees when pootling about, 65 to 70 on a motorway and up to about 80 when pressing on with frequent sudden speed changes
:lol:
Very useful info, and similarly I'd love to remember how to work it all out. Like I said, I'd love to see the temperature curves to understand it. Had all those oil temp/pressure/coolant temp gauges on the Mini, but never watched them with any real interest :roll: The fact that the coolant temperature is measured in the smaller closed circuit (excluding-radiator) zone may cloud the issue a touch, I guess, too.

The diff temps you see make total sense to me in each operating condition.
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Post by ade and liz flint » Mon May 21, 2012 1:54 pm

Chas wrote:I would have expected the same, especially since the specific heat capacity of water is 4.2 against oil of around 2. However, I've noticed this will all cars having both oil and water temperature gauges. The E34 M5 and B10 BT both took far longer to get their oil up to temperature.

I've made the point before that people shouldn't assume they can give their car the beans just because the water is up to temperature because the oil may only just getting warm :shock:
I've got some thermocouples and a Fluke temperature meter....I'm getting tempted to fit them to the car, now! :lol:
Current:
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Previously loved:
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PORSCHE: Macan S, Cayman 981 S

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