Volkswagen Launches 261 mpg XL1 Plug-in Hybrid, World’s Most Efficient Production Car

If weight was a concern, why have they fit a diesel (with turbo and pollution control systems) into this thing? A light SI engine was much better solution.
But there you go, VW has always interpreted their own laws:

diesel adds weight
fight weight adds cost
cost is for "dem" customers, who cares?

Halo vehicle or a testimony of incompetence facing "green challenges"?

 

The initial Prius Phevs that went on tour were about 600 units. If VW is only going to build about 250 units, what's the point? publicity stunt? bragging rights? I don't get it.

 

It's only a 2 cylinder diesel, I'm sure that vw did their homework and the engine efficiency is greater than the mpg reduction for the added weight. VW's 2L peak efficiency is 42%, the prius ice is 38%. I'm guessing the added energy content of diesel which is about 10% versus gas gives than about 20% higher sweat spot bsfc versus an Atkinson like the one in our prii. I'm ure it added less than 10% higher rolling resistance which means it should be more than a 10% gain in mpg.

As for diesel versus gasoline in a higher volume hybrid or phev production car, VW agrees with you and thinks gas is better. Vw's jetta hybrid uses gasoline and their future golf phev also uses a gasoline ice. The difference in trade off is cost. The added price of diesel is not really worth the efficiency gain when it comes to these cars according to Volkswagen - and most of the automotive world.

 

Engineering demonstration.

The idea is to pull out all the stops to make the most efficient car, then perhaps the engineers will get excited and add the efficiency improvements where it makes sense to other cars.

The most exotic part of the xl1 is the carbon fiber, and vw wants to use more and reduce cost.

This may trickle first from the Lambo and XL1 to some of the audis. I would think carbon fiber hoods and roofs and suspension parts may make it into performance and/or eco models of lower priced cars fairly soon. These won't be low priced cars, but look at bicycles Most won't pay for a cf frame, but a carbon fiber fork is on just about everything.

 

It is def. interesting but based on this quote, it seems its going to be a production car just like a Ferrari is a production car.

They also mentioned implementing some of the XL1's drivetrain into the Up! as the weight is similar so similar improvements might be seen although due to the body style not 200+mpg

 

Sweet looking.
But if I had $100 large, I would be in a Tesla S.

... and making a mint renting it out when I needed and rented some long range vehicle.

 

BSFC is related to kg of fuel spent to produce energy at output shaft. Density of the fuel has nothing to do with it.
But, agree, in MPG does make a diference. At a cost, doubled on complexity and pollutant emissions. VW sees this as a MPG record breaker, but nothing more. Green car? Not much.

And again, best BSFC in a diesel is located somewhere near the maximum torque, a small "island". In an Atkinson it extends for a fairly interesting area. Average BSFC in normal operation (broad rpm-torque demand) is probably better in Atkinson cycle engines.

 

They said beforehand they wanted less than 1 liter per 100km fuelconsumption (which is considered to be a holy-grail-like-number). A diesel made this easier than a gasoline. It really is that simple.

BTW, in many countries diesel is kept cheaper to favour big trucks and to keep trucking goods across our continent 'affordable'.
Diesel is about 15% cheaper than gasoline/petrol, but I pay 2500$ in roadtax for my 3500lb diesel, twice what a petrol car would cost, and >10 times (!!!) what a 30,000lb diesel truck will pay..., but he'll be slapped with extra high-way-tax in e.g. Germany. And my car won't be allowed in certain cities...

 

No, it isn't that simple. VW fuel consumpion is based on EU calculations, which account EV distance possible on one charge. It would be simpler to provide extra 1kwh, instead of go to a diesel.

Please adress to my previous post~...
Volkswagen Launches 261 mpg XL1 Plug-in Hybrid, World’s Most Efficient Production Car | Page 3 | PriusChat

 

I drove by the VW dealer last week and didn't see any on the lot. Has anyone seen one on the lot or test driven?

Bob Wilson

 

showing the Europe how technically advanced VW is... despite reality being opposite

 

That post shows the test consists of a run with full battery and with empty battery.
Easiest is to buy a Tesla Model S, stick a VW badge on it and do the run with full battery, but that leaves you with a problem with the empty battery part of the test. Hmmm, lets stick a small, efficient engine in there that uses the least fuel. Surprise, surprise, that will be a diesel... It simply uses less cubic units of fuel than any other engine based on a normally available fuel.

I'm probably missing something, but in my view it really IS that simple, and the only thing you did by pointing to your post is make this more obvious.

Not trying to raise an argument or be argumentative, but I am either not seeing your point, or I'm maybe just too dumb to understand it.

(PS: I'm in hospital due to my blood not retaining enough oxygen, so the me being too dumb atm to understand is not that far fetched...)

 

CS Mode is very important, that's why XL1 is small, aerodynamic and light. And for CD Mode also.

The question is raised directly to the engine used. Definitely, diesel option has more weight, so both modes have penalties on carrying that burden.

BSFC has been proven very broad in Atkinson cycles charts, which compared to a Diesel relatively small area of better BSFC, along with the complexity of the engine, seems like a no brainer...

(PS: looking forward to your recovery)

 

Well the entire point of the car is to be most efficient - 1L car. If you define green as most efficient, then its green. If you define it as something that will sell in volumes to reduce fuel consumption then no. Having a higher energy density of the fuel definitely helps to go further on a gram or a liter of fuel.

Today's emissions systems are fairly complex on all cars, but most of the problems were worked out years ago.

Diesels do vary well at lean burn, so they can stay efficient at lighter loads. This is the opposite of your statement. The reason the Atkinson does so well in the prius, is the hsd and software keep the load high at any rpm. The gen III adds some diesel tech - cooled egr to help stay efficient at lower and higher power levels. You can clearly see a big improvement in range of efficient bsfc in the gen III versus gen II.

 

At 4.2 inches shorter than a Prius c, no back windows to look thru, bicycle tires and fixed solid top 1/2 side windows, no regular side view mirrors in the demo model yet, this thing will not have better ev range than Chevy Volt and probably will be more expensive than a Tesla. Model S Design Studio | Tesla Motors

 

Yep - two words carbon fiber.

If we think of vehicle evolution like animal evolution evolution - descent with modification, then you will celebrate the diversity of this beast, but understand most of its dna will not survive.

I definitely give vw credit for producing the car though. Its a cross between freedom car and the Honda insight. Both of these programs were not fit for the environment, because they were designed for more oil scarcity than really happened. It is a fairly pure creation for one or two people to commute in a very expensive oil environment. Will some of the pieces survive though to improve other vehicles? We don't yet know. More efficient diesel linked to a high number of gear automatic transmissions - VW is already doing this. Extremely low drag body? We don't know. PHEV - yes definitely in 2014. Carbon fiber - not yet. Ultra low rolling resistance tires. That's the one that I think fails. We are going for more grid, not more narrow tires.

VW's Porsche division has the 918, a beautiful concept also do in 2014. PHEV sports car seems like a great winner.

 

Here's an updated VW XL1 vs. 2011 Volt comparison based on the European NEDC test cycle data that was released:

Code:

Car	Raw mpg	KWh/100 miles EV range	 comb. mpg
XL1	120 (US)  16.0		31 miles  260 (US)

Volt	 47 (US)  27.0		52 miles  196 (US)

Volkswagen 1-litre car - Wikipedia, the free encyclopedia

 

Jeff is Raw CS? If it is we can approximate the xl1 on epa CS by using a factor = 120 NEDC x (37 epa combined/ 47 nedc) = 94 mpg epa combined in charge sustain mode guestimate YMMV. That is slightly less than I was predicting, but in the right ball park.

If you are doing a great deal of driving in charge sustain mode, it may be worth it, but given American driving habits or European driving habits a large percentage will be in charge depletion mode. Say the utility factor on the xl1 is 50% ev, then in 15,000 miles it will use 79 gallons of diesel along with electricity.

 

To effectely increase BSFC at part load of a turbodiesel, compression ratio has been lowered. But also lowers BSFC sweet spot value. There are no free lunches.

Adding cooled EGR in GenIII has little to do with "diesel tech", unless cooled EGR is ineherent to that kind of engines, which is not. Here it reduzxed pumping losses. I would state that when DI is applied, not cooled EGR.

By they way, VW shouldn't be marketing as "efficient", but a MPG record breaker.

 

Cooled egr was only used in diesels before the gen III prius. The fact is many things that make diesels more efficient at lower loads is can be implemented on gasoline engines. While it is true a diesel will lose efficiency as load is lightened, it does not lose as much efficiency as an Atkinson ice, at least according to the bsfc charts. The way that hsd gets around this problem is by selecting ice rpm fully loaded for the power desired. Then it is no longer a diesel advantage. The ice simply operates at high load at all times unless low power is desired.

Now one reason for pulse and glide is the ice loses efficiency at low power levels, and as already mentioned cooled egr pushes this level further down. DI, one other piece of diesel tech, can further help here, as well as cylinder idling which is a gasoline technique. I expect Toyota to implement di in the next generation prius, but we don't know yet. VW can do cylinder idling on one of their 4 cylinder engines, and Toyota is likely working on this too. Diesels can avoid throttling losses simply with lean burn, but gasoline can not. Atkinson reduces throttling and pumping losses, but variable lift, which Toyota has can eliminate throttling losses, but with a more expensive engine.

That is happening is gasoline engines are getting more complicated and efficient removing diesels historic advantages. As I said both I and vw agree with you that when money is an object gasoline is better than diesel in a hybrid or phev. The Porsche 918, which vw now owns uses gasoline simply for smoothness and power to weight and that is a 700,000 euro car

You don't think 120 us mpg in the nedc test is efficient. Their engineers were challenged to come up with the most efficient car they could in terms of liters/100 km and they have a great engineering achievement. It isn't a marketing achievement though. In the VW group for electrification that is the Porsche engineers with the 918 supercar phev.