When I made that introduction, I was mainly referring to the thermal efficiency of the engine, not the MPG. VW has made many claims regarding their diesels, and now that it's all exposed, we know that none of them are true. Toyota's Atkinson cycle seems more efficient than the diesel cycle, at least for automotive applications. Also, given that VW XL1 has such a small engine, highway mileage would be poor, lowering the actual MPG greatly. On paper, that's for sure. My guess: Given that the diesel Golf gets 36 MPG in EPA tests that are very close to real-world driving, XL1 would get 40, perhaps 45 MPG. Its highway mileage would probably be worse than the Golf, as the 1 L diesel engine would be running in a very inefficient region with the car doing 65 MPH.
Not from what I've read. My impression is that at least one claim is untrue and that VW can't be trusted. Being untrustworthy means that other claims could well be false also but I don't know that they are.
That has to qualified with "in a hybrid". Without the electric, or even hydraulic, motors to supplement the ICE, most people would pass on the reduced power output of an Atkinsonized engine. With their low torque range, a diesel can give the efficiency and the power alone.
The only effect of ULS gasoline I'm aware of is that oil life increases due to less acid build-up from sulfation and therefore engine life increases as well. You can also increase valve life in direct-ignition engines by using less detergent in the oil (low-SAPS oils) as there is less acid to neutralize. Less detergent reduces ash deposits on the valves that results from burning of the detergent. Low SAPS also helps with emissions, catalytic-converter life, oxygen-sensor life, and especially the diesel-particulate-filter life. We've had ULS gasoline in California for decades and it's time for the rest of the US.
wikipedia claims 40% thermal efficiency for diesels, 38% for atkinson. Too close to say which is more efficient than the other. though diesels will never be good engines for hybrids because they are more sensitive to engine temperature to get peak efficiency.
Well, Generation 4 Prius engine for the core model is said to be over 40% efficient. The Prius Eco engine could be even more efficient.
Not likely. Most fuel efficient trims involve areo tweaks and weight reduction, maybe different gear ratios in a traditional transmission. If the engine is more efficient, why not spread the costs and put it in all the trims. Toyota's new small(2.8L?) diesel has 48% efficiency.
The "eco" in Prius eco stands for "economy", not "eco friendly". It's a "stripper". For those on a budget. Yup, the stripped down models often do get better mileage. But that is not usually the reason for their existence. So the Prius eco won't be doing things any differently than the other models, it will just have no options installed. At least that is my understanding based on what Toyota has officially said, reported on this forum.
I'm interested to get official specs. I'm pretty consistently getting 58-61 mpg range in my gen 3. Logic says a gen 4 rated for 60 could see close to 70. iPad ?
Peak efficiency figure means nothing if the operating line can't be maintained there. HSD does a superior job than step gears in Diesel.
44% is the correct number, but Hilux with that engine suposedly gets only marginaly better fuel economy than previous 3.0 model on NEDC:
Ken1784 is posting some interesting information regarding the ECO model in this thread: Gen 4 Staff Manual (In Japanese) =/ Specs/Design/Other Info | Page 4 | PriusChat In post #67, he lists ECO model deletions, aimed at saving weight. Some of them quite severe: no height adjustement of front seats, and no rear spoiler for example. Reading the link (in the same posting), it seems the main, maybe sole reason for the ECO model is to have a lighter model which puts the car in a more favourable mpg testing regime?
