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Roger, Don't put too much trust in rumors. Lots of people speculated that the current (gen 3) Prius would get nearly 100 mpg. In actual fact, it gets almost exactly the same mileage as the gen 2 Prius, and the later Prius C is somewhat worse, given its smaller size. That's why I find it more appropriate to compare cars that are available right now.
Roger, I think that the more fair comparison is between current models, not past models. That's the choice that a current consumer will face. It's also fair to compare the Prius to the most fuel-efficient Corolla. One assumes that fuel-economy-conscious consumers will compare these two options rather than comparing a Prius to a rental-spec Corolla. It also brings the price difference closer to the $5,000 range which is more reasonable. Comparing fuel economy of cars that are more than $10,000 apart is artificial. $10,000 is 20 years of Prius fuel savings (according to the EPA). You may as well invest the $10K and get a "free" 2034 Prius (or two).
Roger, As the article above clearly states, these Walmart trucks are intended for short hauls from distribution centres to stores. Think of them as giant Priuses that efficiently use battery power in stop-and-go conditions and use a small turbine to recharge the battery packs. Many here have suggested using turbines in hybrid cars, but they are too expensive and complicated for consumer vehicles. Walmart has done the maths and calculated that it can work in their favour in short-haul trucks for a specific use case. Just like hybrid buses can work in urban mass transit scenarios, even if they do not work for intercity (Greyhound) bus routes. The flip side to this, of course, is that long-haul solutions do not provide an advantage in suburban mixed traffic.
According to the EPA, the current Corolla Eco gets a 30/42 (average 35) rating, to the current Prius's 51/48 (average 50), so the difference is almost exactly 30% (or $500/year). It makes sense that hybrids do comparatively better in congested traffic. That's where hybrid powertrains really shine. The Prius's slight highway advantage over the Corolla is mostly thanks to the Prius's slippery aerodynamics and rock-hard tires. In that way, hybrids may make more financial sense in India and China, provided that fuel costs justify the initial financial hit. As we've seen in other articles, they are definitely beneficial to the taxi industry.
Roger, If you go back a few days on this site, you will see that Mercedes has implemented a closing radiator flap on the new C Class. Other manufacturers have done so before (Cruze Eco and Dart Aero for instance). Mercedes only claims single-digit efficiency gains, and a good part of that is from heat retention on start-stop. If you really can get this down by an order of magnitude, contact them immediately. They will give you the keys to the kingdom and let you implement all of the "1000% improvement" technologies that you've suggested here over the years. You are obviously a very smart guy, but you also have a tendency to wildly exaggerate. That's not helped by the fact that you never ever admit that one of your guesses is off the mark. That's too bad. I mostly ignore what you write (as I know many others do), but every once in a while feel the need to remind you that this site promotes ideas based on science and not just wishful thinking. It's nothing personal, and realistically, it's probably more my problem than yours. Carry on!
Roger, I guess that this is the closest you get admitting that you made-up a "fact". You've re-estimated from <1% to 15%. My sources say 1/3, but at least you are now within an order of magnitude. Aircraft travel through colder air at much higher speeds. They also operate close to their design load all the time (operators hate empty seats). That makes the job of cooling them much different. Back on the ground, I've read that some F1 cars have generated slight thrust from their radiators, but that this amount was negligible. The cooling system as a whole creates drag, of course.
Roger, Cooling needs are proportional to overall drag. That's because the engine is creating the torque to overcome that drag. Think about it: the trailer creates tremendous drag. The engine generates enough power to overcome that drag. The engine is less than 50% efficient, so over half of the fuel's energy is dissipated as heat, using radiators. Radiators are air-cooled, which creates drag. The 1/3 rule applies at speed (no one cares about drag at idle!). Variable radiator louvers lower drag somewhat, but not by >97%, as you assumed. The efficiency gain is in the single digit range. Then again, if you really have worked-out a system that limits cooling drag to under 1%, you should patent it and let the planet benefit. You will make millions, and the world will save billions.
Some of the commenters seem to have missed the key point that Walmart's "transport vehicles have shorter transit times". This means more stop-and-go, and less time spent at freeway speeds where conventional diesels reach their peak efficiency. A turbine generator that only operates at its (lower) peak efficiency will be better than an idling big diesel.
Roger, The rule of thumb for aerodynamics on cars is of an even split (1/3, 1/3, 1/3) between cooling, underbody and visible surfaces. In other words, cooling systems contribute more-or-less 33% of drag on cars. I'm sure that the numbers are different for tractor trailers, but I would be surprised if the difference was as big as your estimate.
Peter, I said that the gap can become immaterial, not that it was immaterial right now. Obviously, this starts with smaller cars. They use less fuel (which means that potential savings are less), and are more cost-critical. They also have limited space for things like particulate filters and urea tanks, and their suspension/brakes may be less tolerant of the weight penalty of a diesel powertrain. As we've seen, some automakers no longer offer diesels on their smallest platforms. If, as you predict, the gap between gasoline and diesel gets smaller over time, then we can expect that the smallest diesel-friendly segment will grow every few years. Right now, sub-minis (A segment) no longer derive an economic advantage from diesel. We can expect this to move to the marginally bigger B segment (Ford Fiesta, VW Polo) quickly, and to the C segment (Golf, Focus) by the end of the decade. Of course, this trend may be accelerated by the fact that the cost of diesel compliance keeps increasing, whereas the efficiency of diesel has not improved significantly in quite a while (since the first high pressure injection models of the mid 1990s). Also, while I am sure that diesels can be made just as clean as gasoline cars (at a cost, obviously), I'm not sure that the social stigma of diesel can be negated soon. Previously pro-diesel markets such as France and Italy are now openly rebelling against politicians who subsidized diesels in the past. Diesel market shares are dropping significantly (down 5% since their peak 10 years ago), and air pollution alerts are being blamed on diesel (smog days in Paris last week). That's a lot of bad PR to fight, and I am convinced that automakers will seize the opportunity to sell new gasoline/hybrid/electric cars rather than being seen on the loosing side of a debate that prominently features kids with cancer. It doesn't matter who is wrong or right, no big corporation wants to be associated with that image.
Peter XX, The efficiency gap between gasoline and diesel may never dissapear, but the difference can become so small as to be immaterial. A 1 l/100 km gap means 200 l per 20,000 km (a representative yearly driving distance). The cost of those 200 l of gasoline has to be weighed against the extra initial cost of buying a diesel-powered car, as well as extra regular maintenance costs (and urea refills if so equipped). Add to this a social backlash against diesel (WHO calls it a carcinogen, large cities want to ban it, it's more likely to leave a odour on your hands after filling-up), and diesel may not be cost-effective for most regular users. It's not a coincidence that the latest city cars from Citroen, Peugeot, Renault and Toyota are gasoline-only.
So you have a car that's bigger, faster, safer, better handling, more stylish than a Prius, with a slight fuel economy penalty (but only after the first 20 miles). Seems fair. People also pay extra to go to a nice restaurant or to wear nice clothes. Seriously, I doubt that the Prius is this car's main competition.
Jus7tme, Aren't you double-counting? The electricity is either produced by the motor, or grid-supplied. Not both. Your grid numbers seem a bit high, but I guess that they are correct somewhere.
It's funny how the regular commenters on a green car blog are appalled that public transit is increasing in popularity. Let's revisit some long-term trends before we blame the Illuminati. People are marrying later, moving to the suburbs later and having children later (not necessarily in that order, of course). Car-obsessed baby boomers are retiring and dying. Some of the hottest real estate is in cities, and many families stay close to downtown and public transit at an age when their parents moved to suburbia. Witness Brooklyn for instance, or even Montreal's Plateau where flats that were worth mid-5 figures in the 1990s are now pushing 7 figures. Are the rich getting richer? Compare Versailles or the Medici palace to the much-televised homes of recently deposed dictators. Total dominion over a decent fraction of the world's population buys you a slightly bigger version of a McMansion. Even the ultra-rich's hoarded art treasures are second-rate. On topic: their humongous SUVs are not noticeably bigger or more richly appointed than regular folk's SUVs.
Roger, I trust that you understand that your lockup-clutch idea is heavier and more complex than a normal two-motor system, which itself is heavier and more complex than Tesla's efficient single motor system. Any theoretical energy savings gained during the <1% of the time that a car is driving dead straight on a perfectly flat uncambered road would be minuscule compared to the cost of hauling added dead weight. Side note: no public road should be perfectly flat and uncambered, because such a road would never drain. Perhaps a driveway made from an unusually smooth concrete pad could meet this criteria.
Roger, If you had two motors, as per your speculative layout, you wouldn't need a lock-up clutch. You could just run the two motors at the same speed. A centre "peg-in-hole" lockup clutch would only be useful when the car is going dead straight on perfectly flat pavement. Any slight deviation would result either in huge driveline stress, or in huge wear on your centre (non-)diff. It would be like driving an old-style part-time 4wd on dry pavement: you would get a huge repair bill after just a few miles.
Roger, You would replace the differential with a lock-up clutch differential. What makes you think it would weigh any less? Nascar's premier series uses differentials. You are thinking of dirt track cars.
kelly, The Jeep/ZF 9-speed transmission has four planetary gear sets rather than the three found in most current automatics. There is no reason to believe that the fourth gear set will be any less reliable than the other three. This type of automatic transmission will typically fail due to overheating, inappropriate transmission fluid, or driveline shock (tyres suddenly losing traction and then hooking up). None of these issues are made worse by having more gear ratios.
Michael, Lots of big imported trucks in the US commercial truck market. The F650 competes with Mitsubishi Fuso and Isuzu. I think that the Propane/CNG option is key for the petrol engines. That can represent a significant savings for fleets that have access to those fuels, and it's much preferred in applications where workers or customers will be directly exposed to exhaust fumes. It's common in airport vans, for instance.
Peter, This article is about stratified lean-burn combustion as used in the A Class and B Class (Golf/Focus-sized family cars).
Michael, That is exactly my point. People often conveniently forget that European tradespeople also drive large trucks, and that Europeans in general are just as fond of big SUVs as Americans are. Europeans brag about the fact that they don't buy many American SUVs (except for Jeep Grand Cherokees and Wranglers, which they absolutely love...), but then they buy 2.5 ton Range Rovers and Mercedes instead, so the difference is irrelevant.
It's not an oversized engine if you need the torque. If you don't need the torque, you can get a much cheaper 4 cylinder gasoline Frontier.
This car is very similar to the Cruze diesel, which is sold alongside pickups and SUVs in US Chevrolet dealerships. Clearly Americans have the opportunity to buy this type of car, but they choose not to. I bet that Europeans would love to own pickup trucks and big SUVs. Given the plague of Range Rovers in bigger European cities, it seems like the only thing preventing most Europeans from buying large trucks is economics.
Michael, They do sell Japanese cab-over trucks in the US. These are in a higher size, weight and price category (5 ton capacity vs. roughly 1 ton for pickups). They are also harder to drive, less comfortable and noisier. Peter, You shouldn't directly compare European and US (EPA) mpg ratings. Even cars that are identical in both markets get much lower mpg numbers in the US. Contrary to popular belief, these trucks are the mainstay of American small business. The same businesses in Europe often use vans that get similar real-life fuels economy numbers.