RE: VW Golf GTE: Driven (briefly)

[Adeyfisher]

With the growing popularity of these plug in vehicles, I think we (the EU) really need to set some parameters for fuel consumption figure statements, as there are for stand alone ICE powered cars. 'Up to' is just too vague to really have any idea what you'll be buying into.

It will never be accurate but as with published MPGs they would be at least a way for the consumer to compare models.

There is a lot good reason to buy a plug in hybrid, especially if you travel short distances regularly as many do. I would love to buy a Tesla as it would suit my daily needs, however; I live in the Netherlands and regularly drive to France, Germany and back home to the UK for holidays, so electric only just won't work.

The best reason to buy a plug in hybrid here in the Hague is; the Gemente (Council) will install a power point on the street to plug into and therefore guarantee a parking space very close to your front door!

[c8bof]

• useless post alert*

Can't comment on the 'mpg' or whatever of these cars but I was visiting Tempelhof a few weeks ago when they were testing these cars, and they were really hammering round the apron! Very, very quiet until they picked up the pace and then it was just road noise. The VW campers there at the same time were pretty cool too - assuming they were electric too given all the publicity. Was supposed to be looking at the architecture of the airport - spent most of the time watching the cars.

What did strike me about Berlin, was the number of electric car hook ups for charging the cars up, and all were being used. Not just tiny city cars either.

[Devil2575]

A car like this would be ideal for my family. However we aren't in the market for a £28k car. We'll be spending about a third of that on our next car.

[oilit]

Devil2575 said:

A car like this would be ideal for my family. However we aren't in the market for a £28k car. We'll be spending about a third of that on our next car.

you could buy the batteries and maybe the wheels... then save up for the rest ?

[ChesterUK]

My belief is that there still isn't enough financially economical technology to make hybrids viable. We know the industry is spending billions on finding viable methods. Until then, we're getting products that are forced to market through legislation. Aston Martin Cygnet anyone? No?

For now it takes stored energy or material to produce propulsion. Until someone has figured out how to significantly reduce the amount of energy required to propel a vehicle with so many hundreds of kilos (if not thousands) along a road, this will always be an engineer's nemesis. Reducing mass and drag seems to make sense, but then you end up with a Twizzy! Exotic materials can reduce weight but currently cost a fortune.

So I believe we have a long way to go before the 'real solution' is here. For now, we have the pretenders.

[McWigglebum4th]

ChesterUK said:

My belief is that there still isn't enough financially economical technology to make hybrids viable.

So toyota have been selling the prius for over a decade now at a complete loss and haven't turned a single penny in profit on them

ChesterUK said:

Aston Martin Cygnet anyone? No?

I thought despite internet roumours that was actually produced as a real model and not a emissions bodyswerve

[annodomini2]

PunterCam said:

annodomini2 said:

PunterCam said:

My GCSE physics keeps on telling me that the car has to use energy to make energy for the battery, and that converting energy costs energy - it can't be 100% efficient. Fair enough, energy wiped away during deceleration is free energy, but more energy is spent increasing speed than decreasing speed...

So the battery will go flat, and you'll end up with a car that's less efficient than a 1.4tsi golf surely? Unless you plug it in. Or the car is designed to use a large portion of its petrol power to charge the battery, in which case it surely defeats the point (from an efficiency standpoint at least... Huge, instant torque for a sports car (P1) might be more desirable than extra top end power, and so the conversion to electricity might be justified in that scenario...)

Perhaps that fact that I'm using GCSE physics explains my lack of understanding/belief, but I keep thinking that a car that claims 188mpg should actually do just that. If you're having to plug it in to get that "free" energy, then the whole exercise becomes pointless in my opinion. You're just lugging around 200kgs, and then throwing away energy to create electricity... Surely this car is less energy efficient than a regular petrol car?

As JonnyVTEC said it's plugin, but also you will have some of the braking done by the electric motor and recharge the battery that way.

Not 100% recovery as you state, but some energy that would normally be converted to heat in the brakes.

I've always said that I'd be delighted to have an electric car for my day to day travel, but I'm struggling to see the point in these to be honest. It's just a sort of half-way, half arsed, "thing". You can plug it in for a bit, and it uses some electricity before moving to petrol. Yippee. Presumably, like all these systems, there's something like 20 miles of battery only travel, then 400 odd miles of petrol? How on earth can you equate that to 188mpg? (A: you pick a huge number out of thin-air and say that's the mpg of the battery pack).

In reality what it surely does is 380 miles at 40mpg, and 20 miles for free? If you plug it in. And if you don't, what happens? I'm still seriously confused. Where is the energy for the batteries coming from? If you don't plug it in, are these cars not less efficient than a regular car? Will you not in fact have only 100bhp most of the time in that scenario?

I agree the MPG figure is probably bks for the real world, but driving round town you accelerate and stop all the time.

When you slow down some of the kinetic energy the car has is converted back into electricity by the electric motor (like KERS in F1) and charges the battery.

The energy has come from either the fuel feeding the engine or the plug socket, depending on how the vehicle is operating at that moment in time.

The energy comes from the energy that is normally lost (as heat) during braking.

[GarfyJ]

First post - please be gentle.

Those wondering where the 188mpg comes from - well it's the basic economy test. It only uses short distances:

Urban cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20°C to 30°C on a rolling road from a cold start where the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerations and idling. The maximum speed is 31 mph (50 km/h). The average speed 12 mph (19 km/h) and the distance covered is 2.5 miles (4 km).

Extra-urban cycle
The extra-urban cycle is a cycle that is intended to represent the use of the vehicle on roads that are external to the urban environment. The cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving with the remainder being accelerations, decelerations, and some idling. The maximum speed is 75 mph (120 km/h). The average speed is 39 mph (63 km/h) and the distance covered is 4.3 miles (7 km). The cycle is shown as Part Two in the diagram below.

Combined Fuel Consumption Figure
The combined figure presented is for the urban and the extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.

So for most plug-in hybrids - they barely touch the petrol engine, because the test is so short. So ultimately the test is flawed (it probably always was), and now we're trying to add electric into the system and it just won't go.

So if you commute more than 20-30 miles - this is just a Golf Hybrid with a large battery.

[MycroftWard]

GarfyJ said:

The urban test cycle is carried out in a laboratory at an ambient temperature of 20°C to 30°C on a rolling road...

Can I ask, how does an economy test on a rolling road work? I mean, presumably not accelerating the mass of the car, you have no air resistance, etc. How do you get an mpg figure out of that, do you have to compensate with some maths?

[GarfyJ]

I believe a rolling road has some resistance, but as for the air - I'm not sure they do. Hence why none of us ever gets anywhere near the quoted figures.

[STURBO]

From a cost perspective, I think it sounds like a good idea for a lot of company car drivers.

I do about 12k a year. 9k of that is journeys less than 30 miles. I can charge up at work for free.

So I'd have to pay for 3k miles worth of petrol.
And a really low BIK.

And when I want to drive long distances I've got a 1.4 petrol Golf. That'll do about 45mpg.

So worst case driving cost is 45mpg, best case it's free. Even if you are paying for the electricity it's still cheap.

Obviously if you need a car for 20k motorway miles then this is the wrong one for you, get a diesel.

If it drives OK and is nice to be in I think they will sell a lot of them.

[Itsallicanafford]

The Crack Fox said:

I think the word "stunning" is perhaps overdoing it a bit. "Economical and cheap BIK" is perhaps nearer the mark?

Yeah, maybe.... I just get all excited about saving a few quid on tax

[anonymous-user]

MycroftWard said:

GarfyJ said:

The urban test cycle is carried out in a laboratory at an ambient temperature of 20°C to 30°C on a rolling road...

Can I ask, how does an economy test on a rolling road work? I mean, presumably not accelerating the mass of the car, you have no air resistance, etc. How do you get an mpg figure out of that, do you have to compensate with some maths?

The rolling resistance is adjusted to meet the actual measured resistance of the test car. To do that, a test car or cars undergo "coastdown" tests, where they are accelerated up to speed (around 130kph) and allowed to coast down to a stop in neutral. This is done a lot of times, on a flat track, without and wind in both directions until the average result is statistically significant. This gives you the "total" drag curve for the test car.
On the chassis rolls, the system is then programmed to reproduce the same drag force vs wheel speed as the real car saw. On the chassis rolls, this load is confirmed by allowing the car to also do a coastdown test, and ensuring it takes the same amount of time to come to a stop.

On old chassis rolls, the inertia of the car was provided by large iron flywheels (of different sizes and capable of being clutched into the actual drive rollers are required) but modern systems are entirely electrically simulated using a large AC motor to apply the correct load to the drive rollers to simulate the drag curve vs vehicle speed

[anonymous-user]

GarfyJ said:

First post - please be gentle.

Those wondering where the 188mpg comes from - well it's the basic economy test. It only uses short distances:

Urban cycle
The urban test cycle is carried out in a laboratory at an ambient temperature of 20°C to 30°C on a rolling road from a cold start where the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerations and idling. The maximum speed is 31 mph (50 km/h). The average speed 12 mph (19 km/h) and the distance covered is 2.5 miles (4 km).

Extra-urban cycle
The extra-urban cycle is a cycle that is intended to represent the use of the vehicle on roads that are external to the urban environment. The cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving with the remainder being accelerations, decelerations, and some idling. The maximum speed is 75 mph (120 km/h). The average speed is 39 mph (63 km/h) and the distance covered is 4.3 miles (7 km). The cycle is shown as Part Two in the diagram below.

Combined Fuel Consumption Figure
The combined figure presented is for the urban and the extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.

So for most plug-in hybrids - they barely touch the petrol engine, because the test is so short. So ultimately the test is flawed (it probably always was), and now we're trying to add electric into the system and it just won't go.

So if you commute more than 20-30 miles - this is just a Golf Hybrid with a large battery.

However, it's important to note that hybrids do work in the real world because they act to negate a proportion of the cars mass! For example, to get maximum MPG from a conventional engined car you must avoid any braking (because that is energy "wasted" and unrecoverable to heat), but a hybrid that can recapture a proportion of the energy stored in the cars mass as kinetic energy can be driven more "normally" by "normal" drivers and still return a good mpg value.

If you just get on a motorway, and drive at a steady speed without any braking for a long way, then yes, you want the lowest drag most efficient engine you can get (usually a small capacity CI) but in the real world, with traffic congestion, roundabouts, traffic lights and heavy traffic petrol hybrids (like the Prius) can return very good average economy, even with small battery/Emachine systems!

[Jimbo.]

I like this. A lot. But then again I like all the new tech/approaches the drive for fuel efficiency is throwing up

[Matt UK]

CO2: 35g/km CO2

This could make a simply stunning company hack...