## The Golf TDI Diesel-Electric Hybrid Concept: 69 MPG US

##### 04 March 2008
 The Golf TDI Hybrid concept.

The Golf TDI Hybrid concept (earlier post) introduced by Volkswagen at the Geneva Motor Show combines an advanced diesel engine with an electric motor and the latest generation of VW’s seven-speed DSG gearbox. The hybrid concept vehicle is capable of achieving 3.4 L/100km (69 mpg US) of fuel consumption.

At the core of the new Golf TDI Hybrid is a 1.2-liter three-cylinder common rail TDI diesel engine developing 55 kW (74 hp) and 179 Nm (132 lb-ft) of torque. Working either in tandem with the diesel engine or, if required, on its own in all-electric mode, is an electric motor developing 20 kW and 140 Nm (103 lb-ft) of torque. The electric motor also replaces the conventional starter motor and alternator to save weight and improve packaging.

The motor can also operate as a generator, recovering kinetic energy from the car during braking to charge the 220 volt, 45 kg nickel metal hydride battery which has a capacity of 1.4 kWh.

In practice the electric motor powers the vehicle from standstill with the diesel engine only engaging should additional acceleration be required or at higher speeds. In these situations the diesel engine takes over with the electric motor only working if required to supplement the combustion engine – for example, during overtaking manoeuvres. When at a standstill the diesel engine shuts down completely to conserve fuel and increase efficiency. The energy split is relayed to the driver and passengers through a graphic display accessed through the touchscreen satellite navigation screen.

Drive on the concept car is channeled through the new seven-speed DSG twin-clutch gearbox. This features a pair of dry clutches as opposed to wet clutches.

Visual changes which differentiate the Golf TDI Hybrid include a new, unique grille design, smaller front air intakes to reduce aerodynamic drag and ‘TDI-Hybrid’ badging. The Golf TDI Hybrid also sits lower than the standard Golf on revised suspension and adopts the front splitter from the Golf GTI Edition 30 to help further reduce aerodynamic drag.

The Golf TDI Hybrid is currently a concept vehicle, but Volkswagen says that a version of this vehicle is likely to go into production in the future.

This study follows the recent launch of the efficient new Golf BlueMotion. Adopting an optimized 1.9-liter, four-cylinder diesel engine linked to a revised gearbox and more efficient aerodynamics the Golf BlueMotion can achieve a combined 4.5 L/100km (52.3 mpg US) while emitting just 119 g/km of CO2.

In before the ranting lunatics start complaining that its "NOT GREEN ENOUGH!"

Brilliant!!

This is not then end answer, but a great step forward

should not get to excited , remember after ten years
we still only have one affordable gas -hybrid

Impressive but no doubt expensive. Fleet average CO2 emissions would be reduced by more if the same manufacturing cost were used to make start-stop functionality and intelligent alternators standard equipment on more models.

The problem is that marketing departments have not yet figured out how to sell consumers on the idea of paying a small premium to do their bit for society. The entire industry assumes consumers are selfish and will only voluntarily spend on features that directly benefit them. Yet those same consumers are also voters who have elected politicians that are now forcing the industry to address fuel economy / CO2 emissions.

If we assume that citizens are behaving rationally, then the conclusion is clear: they simply do not trust other consumers will also "do their bit" without legal coercion - peer pressure alone isn't working, witness the rising market share of SUVs in Europe in spite of widespread disapproval.

The situation is analogous to the introduction of unleaded gasoline and three-way catalysts. Bear in mind those addressed tangible effects on local population health rather than the more abstract notion of global warming.

PSA citroen demonstrated the same concept of diesel-hybrid, with simalar performances 2 years ago. but didn't bring it to market for the reason Rafael said. The consummer wants better fuel efficiency but doesn't want to pay a premium for it. But this could change 2/3 years from now when undoubtedly the price of gaz will go through the roof.

They are predicting $4 per gallon gas in California this year, which makes the payback time a bit less. well i don't know, if this car doesn't cost more then 2000 then the diesel version, maybe we can buy it ... i still have hopes, that the VW UP gets the same without hybrid function and this at half of the price ... @ Sjc - diesel costs EUr 1.06/L ($6/US gallon) in Germany right now, but there is still no diesel hybrid on the market. The reason is simple: in purely financial terms, hybrids remain a marginal proposition at best for most manufacturers. Toyota decided to make all the components in house, but no outsider really knows if that means they are turning a profit on them.

Assume the driver of a frugal new diesel vehicle will average 20,000km annually for the first five years. Assume that the hybrid saves 1L/100km, which is agressive relative to a baseline consumption of less than 5L/100km. He'll save 200L/year, i.e. 1000L over the five-year period. Even assuming the average cost of diesel will rise to EUR 1.25/L over this period, that's still just EUR 250 per year. Assume he invests the savings at 5% nominal interest at an inflation rate of 2.5%. The inflation-adjusted value of his savings after five years is ~EUR 1300.

Now, let's assume the vehicle depreciates at a nominal 15% a year. After 5 years, the inflation-adjusted value will be ~38% of the initial purchase price. This is also true of the hybrid components. To break even after five years, the actual purchase price premium for them must be no higher than ~EUR 2100. Since there are markups along the way, that implies a manufacturing cost premium of well under EUR 1500 for the hybrid version relative to the base.

Even accounting for the smaller, simpler ICE and the elimination of starter motor, alternator and 12V battery, that is a very small budget for a 30hp mild hybrid system.

Rafael - all good points. Just shows that at $6 or even$8 a gallon, it is hard to justify diesel hybrids on cost alone - for a small car.

But don't you think that 1500 Euro is a reasonable cost in volume for what they are describing? Also if you do the same thing to a larger car, the payback is much faster. The reality is that going from 25 to 50 mpg is an amazing $$saver, but going from 50 to 75 mpg is not. All$$ should be spent going from 25 to 50 (which is easier in the first place).

"All  should be spent going from 25 to 50 (which is easier in the first place)."

this is the low-hanging fruit and you are right, of course, which is why BMW has rolled out EfficientDynamics across their entire range, but in general anyone who is prepared to buy a 25mpg car probably doesn't care, or doesn't care enough, about fuel efficiency to make it a pivotal factor in their purchasing decision; so if customers don't care, where is the incentive for manufacturers to change it? it is much easier to market a "deep green" car specifically to people who are environmentally aware than it is to market a "slightly greener" car to the general market. at the moment "deep green" cars are still a niche market.

@Rafael,

Diesel Prices in Germany are quite a bit higher. See
http://www.bmwa.gv.at/BMWA/Service/Benzinpreismonitor/EU_Bruttopreise_Dieselkraftstoff/default.htm
for a comprehensive list of fuel prices in the EU.

But David is right, rationalizing on cost is necessary, but definitely not the main driver; in the US, hybrids are seen as green vehicles (positive), whereas in the EU, continous bombardment by the (local manufacturer influenced) media, car magazines as well as newspapers reiterating the MUCH higher upfront cost, and doubtably overall emissions impact have resulted in an image of hybrids wasting precious resources and using toxic and costly materials.

I'm quite eager to see what VW's home publication, AutoBild, will have to say IF this contraption will ever see a real showroom floor for real sale :)

BTW: The specs of the battery sound extremely similar as those of the NHW11 (old) Prius; I know that VW did cannibalize a number of those to build their VW Bora Diesel Hybrid prototype a number of years back (2001 or 2002). If it really took VW that long to move from prototype to motor show concept, I'll probably be driving a Prius IV (LiIon PHV w/ extended reach) by the time this vehicle comes to the showroom...

And yes, a strategy like efficient dynamics from BMW, where some easy attainable efficiency gains are exploited across ALL vehicles sold, would be a much better approach to reduce overall CO2 emissions...

@ realarms -

sorry, the web page I looked up apparently contained old data. At EUR 1.30/L and rising, the budget for a hybrid system obviously goes up a few hundred Euros.

Note that this is just a concept. It's entirely possible any production version would feature lighter, cheaper Li-ion batteries instead.

@ David Pilati -

18 months ago, Citroen was suggesting the markup for its mild hybrid system would have been more like EUR 6000 - which is why they didn't take it into production. Even if somehow, magically, that has been halved by now, cost is still a huge headache.

High unit volume would be the best way to bring it down further, one reason manufacturers are leaning heavily on the supply chain. Nevertheless, even with legal coercion to bring down fleet average CO2 emissions, it will remain difficult to convince consumers to invest heavily in high fuel economy.

It may take quite some time and even higher fuel prices to achieve the unit volumes required to break even. Of course, Porsche Automobil Holding SE may allow VW to cross-subsidize diesel hybrid technology for a number of years to develop a market for it in Europe. After all, the Porsche brand needs sales of frugal models to compensate for its own gas guzzlers in the corporate CO2 tally.

So if the question returns to cost again, perhaps it would be more prudent and cost effective to roll-out an EV capable 20-mile PHEV model, rather than just a hybrid?

Yes it would be more expensive than the hybrid, but perhaps the savings would so much more dramatic (say, 1,000 Euros per year if using EV a lot?), that it actually makes sense to jump one step further?

The most important problem I see with Diesel engines, is that mother nature has thrown two frustrating show-stoppers in our faces: Oxides of nitrogen and fine particulates. The latter, have been blamed for various health problems and the former have always been a show-stopper not only with Diesel engines, but lean-burn engines in general.

If these problems can be resolved, I look forward to seeing this super-efficient Diesel-hybrid hatchback on the highways and byways of America.

You need incentives? If it really is true (and remember, this is an important if) the sky is falling and Manhattan will be flooded from human-caused global warming, then I believe we should tax motor fuels to $4.00 for unleaded regular gasoline (but remember, the vehicle under discussion here is a Diesel), unless however the price rises to that level owing to supply-and-demand factors. @clett: Unfortunately, with european consumer electricity costs, especially if you insist on green power (hydro, wind, solar) there is not really is a big incentive towards PHV (PHEV). The UK might be different (completely different price structure), but last time I calculated running costs using standard consumer rates, and a gasoline price of ~1 EUR/l, using electricity didn't came back with much of a margin. I have to admit, this was quite some time ago (when I experimented with a 2nd battery plus recharger in my Prius I, prior to Felix Kramer starting CalCars). Probably gasoline prices rised much more than electricity rates (especially since there is now more competition on the latter market). But the ROI would probably be beyond the useable life of the vehicle. OTGH, many consumers never calculate the ROI of upgrading fender, alloy wheels, sound systems and the like. With proper marketing and social incentives (like in the US), PHEVs might still attract a lot of people. Hmm... using http://tarifkalkulator.e-control.at/tarifkalkulator/ and assuming 8000 km/a covered by PHEV, at a calculated consumption of 13 kWh/100km (130 Wh/km) ~= 5l gasoline/100km, electricity comes in at around 170-230 EUR/a; gasoline at the current 1,3 EUR/l level at around 520 EUR/a. Not including interest and inflation, as well as likely gasoline price shifts, a PHV20, requiring a ~5kWh battery should not be more costly than some 1500 EUR over a base hybrid (5years). Still not very attractive @ Alex - this particular hatchback with its 1.2L diesel hybrid drivetrain will almost certainly not make it across the pond. However, models with conventional diesels with DPFs and NOx aftertreatment systems to meet EPA T2B5 = CARB LEV II will be launched in the US market this year and next. @Alex: Rest assured, that even at 10 USD/gal prices, business as usual will probably continue... The Netherlands have prices of 1,55 EUR/l today (8,9 USD/gal), and SUVs are quite popular there, despite a hefty 45% luxury tax on top of the 20% sales tax for new cars in NL... Just try to not be in NY when the storm flood arrives... It seems obvious that cheaper mild hybrids is not a very good economic investment unless fuel hits$10+ a gallon.

However, PHEVs 20 to 60 are very different because one may almost stop using liquid fuels and, depending where you are, almost stop polluting with your vehicle.

Since many of us are very close to the all mighty dollar, a mix of mild hybrids, improved hybrids and PHEVs could still contribute to lower liquid fuel consumption and associated GHG.

A progressive liquid fuel (5 cents/month/gallon) carbon tax + a proportional $5,000 to$10,000 tax credit for vehicles with better than 50 mpg to 100 mpg could help convince more buyers to buy cleaner vehicles, even at a higher price.

If nothing is done, it will take decades to transition from current ICE gas guzzlers to improved hybrids and PHEVs.

PS: $200+ oil price may also help to accellerate the transition but could kill the USA dollar. E100 oil is what you should be frightened of..... @Realarms, here in the UK, EV certainly makes financial sense. We can buy a litre of fuel for about £1.10, but a kWh of electricity costs only £0.11 (during the day) or half that at night. 1 litre of fuel could take you 11 miles if driven gently at 50 mpg (10 pence per mile). But 1 kWh of electricity can take you 5 miles, if assuming 98% efficient modern lithium-ion battery (2 pence per mile if charging at peak rates). So you can save 8 pence for every mile done on electric power rather than fossil fuel. Over 12,000 miles in a year, that would add up to a saving of £960. With A123 saying that they're going to make their PHEV packs for$300 per kWh, the 5 kW pack you mention should only cost $1,500 or £750. A PHEV could make back the extra cost of its battery cost in just ONE YEAR if (i) most miles were done on electric and (ii) A123 deliver on their$300 per kWh promise. In reality it's not likely that either of these conditions will be met, but they won't be too far off....

HAHA I knew it.

Diesel is 1.20EUR here in this part of France at the supermarkets - over 1.30 elsewhere and probably going up again now that oil is back over $100. Matt Simmons said in his interview on EVWorld this week that the entire Middle East is about to start a North Sea like decline - that's up to 15% per year, certainly over 10%. By "about to" he means this year or 2009. Terrifying, absolutely terrifying. A few years abck IXIS warned, partly to get attention, that oil would hit US$380 a barrel in the early 2010s. Well, demand destruction would stop that first. But even say US$10/ gallon for crude oil,$420 a barrel - well, $5 a gallon for crude is "only" US$210 a barrel - is $5 a gallon for refined gasoline out of the question now in the USA in the relatively near future, so say$150 a barrel of crude guesstimate?

Yes, $200 or even more per barrel does not become quite so unimaginable now we are at$100 and production falling all over the map. Never mind the price - availability will become rationed.

Clett, it's hard to put 12k miles per year on a 5 kWh pack. GM Volt is 16 kWh and will only do about 10k EV miles per year for average drivers.

There is a good point - if gasoline was rationed, this would be a much more powerful incentive to buy an efficient car.
The problem with letting price ration fuel is that the rich get to buy it (!) - but they are the ones who have the money to buy more expensive efficient cars.
If you ration it, the poor get to drive less in existing cars, while the rich buy expensive cars, and drive more miles.
This is probably better than the poor being unable to drive at all.
It would certainly spur innovation if every family was rationed 1500L of fuel / year.

"The problem with letting price ration fuel is that the rich get to buy it (!) - but they are the ones who have the money to buy more expensive efficient cars."

Cry me a river. Its your own fault you're not rich you dirty communist.

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