What Makes Hybrids Awesome: The Engine

February 8th, 2012 by Potato

Hybrids (like my Prius) contain many awesome innovations that give it that great efficiency, leading to lower fuel use (and lower expenses!). With plug-in hybrids starting to hit the market, the ways that technology provides efficiencies increase. Yet even though hybrids have been around for well over a decade, they are still very poorly understood (particularly by auto journalists).

Quick, which one innovation contributes the largest portion of the fuel savings in a hybrid like the Prius, is it:

a) regenerative braking
b) exhaust gas recirculation
c) atkinson-like cycle engine
d) electric motors and a battery to power acceleration
e) aerodynamics, including a tear-drop shape and a plastic cover for the underside to smooth airflow
f) lightweight aluminum construction
g) low rolling resistance tires
h) continuously variable transmission
i) an engine that turns off when not in use (coasting, at stops)

All of those innovations (and I’m sure a few I’ve forgotten) add to the efficiencies. Odds are good that you answered a, or d, or i, since those are the items that are the most distinctive about a hybrid, and which get the most press. And of course, none of those three are of much good when smoothly cruising on the highway, which is why auto writers keep saying stupid, easily disprovable things like “all that hybrid gear is useless on the highway.”

Yet a quick check of fuel consumption ratings shows that indeed, hybrids get fantastic highway mileage. The gap between them and a regular car isn’t as wide in the highway cycle as in city driving, but it’s still a really good improvement. So why is that?

It’s because the actual answer is (c): the atkinson-like cycle engine. Estimates vary, but something like half of the total improvement in overall mileage (and nearly all of the highway-rating boost) is because the engine is simply more efficient at turning hydrocarbons into motion (the “thermal efficiency”). All that business with the electric motors helps, and there certainly is some benefit from pairing the properties of an electric motor (which generates maximum torque at low RPM, and is great for helping to meet peak demand) with a gas engine (which needs to rev up to produce acceleration, and which has a high-density fuel source for steady-state power demands), but it’s there largely because with an Atkinson engine, you’re not going to get anything approaching an acceptable 0-60 time. That efficient engine needs help getting going.

If you wanted (e.g.: if you’re an automotive engineering student looking for a summer project), you could strip out all the electronic stuff from a hybrid and just drive around with the Atkinson engine, and you’d get a big part of the benefit. Of course, you couldn’t actually use that in traffic since it would take you forever to accelerate, but on a closed course to prove a point…

Anyway, once you’ve got the electric motor in there for the acceleration boost, you can do all the extra tricks with it to squeeze out even more efficiency, like shutting off the engine when coasting, regenerative braking, etc.

So now that you know about the importance of the Atkinson-cycle engine, you see why hybrids still rock on the highway. In fact, improved thermal efficiency is also the reason why diesels get decent fuel consumption numbers on the highway: the higher compression of a turbo diesel is also more efficient at turning hydrocarbons into motion. In terms of litres burned per hundred kilometers, diesel (like a Jetta or Golf TDI) is on par with a hybrid like the Prius; though once you factor in the higher energy density of diesel, well, you can see who the winner is (and I won’t get into the issue of city driving, too).

And of course, knowing that this is the single biggest source of efficiency is why I was so upset that GM didn’t include an Atkinson-like engine in the Volt, instead just slapping in an off-the-shelf engine, which is why its efficiency isn’t so great once the charge from the plug-in is used up.

In Which I Become Idiosyncratically Angry At Auto Journalists And Their Continued Ignorance

February 6th, 2012 by Potato

Another idiodic piece about hybrids in the press. It never fails that they say such inflammatorily stupid things that I get all angry at them. It shouldn’t be all that surprising: you don’t become an automotive journalist because you’re smart or know science or can do basic math, you do it because you like G-forces and want to make engine noises all day. You crave the open road and have an expense account for gas. The typical automotive journalist is about as far from a hybrid buyer as one could possibly get.

But for people who are stuck in stop-and-go and pay for their own gas, a fuel-efficient hybrid is a great choice.

Asking “why carry around the battery on the highway” is like asking “why carry around gears 1-5+R if I’m only going to use 6th on the highway?” except even dumber. If you bother to look up the ratings, you’ll see that not only is the Prius efficient in the city, it is also head-and-shoulders above any gasser on the highway — even diesels. Holy crap, it even beats out the tiny Smart Fortwo by almost 20%. There might just be something to this hybrid thing. I could go into the why of it*, but the point is it’s an extremely easy fact to check, yet I’ve seen these assclowns get it wrong so. many. times.

And if you’re a travelling salesman? Then a hybrid should be the only thing on your shopping list. With a lot of miles to put on, you’ll find the payback to be phenomenal. Ditto taxi drivers, who have found it’s cheaper to get a brand new Prius than a surplus former police cruiser Crown Vic.

“So hybrids, apart from their benefit for city drivers, have failed to sweep the world. Will anything change this pattern?”

Perhaps if instead of panning them at nearly every opportunity, if auto journalists actually came out and started writing some articles more along the lines of “well, the ride’s ok, I guess, and by paying a few thousand more up-front, you’ll save thousands in fuel expenses over the life of the car. If you do a lot of city commuting, or a tonne of driving in general like a travelling salesman, you should take a look.” Then maybe people might buy.

And on the heels of that ill-informed article, this diesel-scented turd.

“Diesel fuel should be taxed at a lower rate than gasoline for one simple reason: the fuel carries more energy than a comparable amount of gasoline, thus it is more efficient.”

Actually, that’s a good argument for diesel to be taxed more on a per-litre basis, since it’s using more barrels of oil per litre to make. But, the fact is, diesel is taxed less than gasoline: the federal excise tax is 10 cents/L on gasoline, and 4 cents/L on diesel. In Ontario, the provincial excise tax on gasoline is 14.7 vs 14.3 cents/L on diesel fuel.

“The fuel-efficient turbodiesel delivers the highway fuel economy of a Toyota Camry sedan.”

…without accounting for the higher energy density of diesel, and allowing for a very large fudge factor (using the V6 Camry vs the more popular V4, and even then, he’s off by over 6%; off by over 21% when comparing to the 4-cylinder).

Now, I’m not totally against diesel: it is more efficient than gas in many driving conditions (though not more efficient than a hybrid, and with about the same cost premium). A select few models will end up being cheaper over their lifetime than a conventional gas car. But it is a dirtier fuel, and one of the benefits of hybrids is reduced emissions as well as efficiency: diesel presents a trade-off (better efficiency but higher emissions). I simply don’t get the auto-journalists’ thinking of “diesel good, saves money and fun; hybrid bad, costs more up front” when it could have just as easily been the opposite. I suppose it’s their pre-existing bias towards diesel (more torque, grunt grunt grunt). It seems so arbitrary since those positions could easily be reversed (“The diesel Touareg is $5000 more than the gas version, a premium that would take over twenty years to break-even on.” “There is hardly any difference in fuel economy in city cycle driving, and with diesel fuel a bit more expensive than regular unleaded, there’s no point if you do anything but cruise the open road.” “The new emissions systems for them are completely untested, and with so few VW diesels on the road, good luck finding a mechanic if you run into a problem down the road.” “The AdBlu emissions control additive will need to be replaced frequently, and VW is very secretive about the pricing. Unverified rumours we are too lazy to fact check indicate that this could cost you an additional $5000 down the road.” “Diesel: fine for early adopters, but not ready for primetime.”)

* – Because the engine is more efficient. Atkinson cycle, yadda yadda yadda. And that is because the battery and motors are there for peak demand. Even on the highway they are used (e.g., to pass, or go uphill). It’s a far cry from dead weight — and even if it is, well, the numbers speak for themselves.

GM: Engineered to Fail

January 21st, 2012 by Potato

Aside from the one a week and a half ago, I haven’t ranted on hybrids & EVs in a while. Nelson had a post at SPF talking about the GM Volt that kind of opened the door though, so here I go. There are a lot of nits to be picked: it’s less of a back-of-the-napkin analysis than a wave-your-hands-in-the-air-and-throw-a-dart analysis. He didn’t even use a spreadsheet! …But that’s not the main point. The point is, the Volt doesn’t seem to offer compelling value, even with the subsidies.

First up, in general efficient hybrids make a lot of sense. I’ve shown this again and again: you make the extra cost of the upgrade back several times over over the life of the car, which can lead to tremendous savings, though of course that always has some factors that can change the balance like gas prices or your driving habits. I made the ridiculous spreadsheet for you to figure it out yourself more precisely.

EVs make a lot of environmental sense: more efficiency, lower emissions, yadda yadda yadda. But it’s not clear yet if they’ll be financial slam-dunks like the efficient hybrids, in part because the first few models are only just hitting the showrooms now. They’re going to cost more up front, but require less maintenance and use cheaper power (especially off-peak). There are some other trade-offs, most notably range anxiety. They’re not going to be the car for everyone, but they don’t have to be — no single car is.

To help combat the big range anxiety factor, plug-in hybrids (PHVs) were developed: you could run off electricity for your daily commute, but still have the gas engine for longer trips.

The Chevy (GM) Volt is the first PHV to hit the market, with the plug-in Prius to follow later in the year. Now, I haven’t yet had a chance to see a Volt in person, but everything I’ve seen from the very first announcement has suggested that GM created it to fail.

Why not? They created their previous hybrids in a way that suggests they were trying to fail: the mild hybrid stop-start system was the cheapest upgrade from a regular car out there, and yet the least economical since it provided hardly any gas savings. Then the two-mode system was developed for the largest of the large SUVs, and it’s complex, expensive, and only offers modest efficiency improvements. But hey, you can tow with it. Basically everything was geared to sell more large SUVs: either hybrids that didn’t work whose sole purpose seemed to be so GM could shrug and say “oh noes, no one wants to buy hybrids. Guess we’ll just build SUVs” or hybridized SUVs, so they could say “well, the American consumer really wants an SUV.” If you’ll allow me to indulge in a bit of conspiracy theory thinking, GM was behind a lot of the anti-hybrid FUD spread in the early days, with ties to the CNW report. Many of their executives certainly didn’t hide their disdain for new technology and saving fuel. And of course, this was the company that took perfectly functional electric cars and crushed them. They wanted very much to just keep building gassers and hoped hybrids and EVs would go away never to return.

So the Volt was announced at a time of desperation: gas prices were spiking upwards, and consumers were running away from fuel-gobbling SUVs. The Volt announcement had the air of vapourware: less of a “look at this awesome car we’re putting together that you can buy any day now” and more of a “please don’t run out and buy a Toyota, Honda, or Ford… just hold on for a few more years and we’ll have something for you!” The initial specifications (which I am too lazy to look up now and link to) were clearly unrealistic. The concept versions at autoshows were the antithesis of practical: square, blocky corners with no aerodynamic properties. Huuuge long engine compartment, tiny passenger/storage compartment. Basically, designed to look like a muscle car or land yacht of old. They joked that it would be more aerodynamic backwards. The initial estimates for efficiency were laughable: no way was it going to hit those targets.

Commercials started being aired on TV for a car that hadn’t even been invented yet. It was clearly just another exercise in marketing.

But then the financial crisis hit and GM went bankrupt, and suddenly it seemed like they had to actually make the Volt.

In the end, it is a plug-in hybrid. But that’s about all I can say: instead of taking an Atkinson-cycle engine to get Prius-like efficiency when running off the gas engine, they just grabbed an off-the-shelf Otto cycle 4-cylinder and plopped it in there. Once the initial charge runs out, it gets far worse fuel economy than a Prius — about the same as a regular gasser. It’s expensive, far more expensive than promised in the vapourware state. I don’t have the exact Canadian numbers to work with, but it looks like it only breaks even vs. a gasser, and that’s after the government subsidy. In the end, a Prius or other efficient hybrid would be the smarter choice (or perhaps a true EV like a Leaf, though I don’t yet have the specs for that, either).

It’s ugly, and that’s coming from a Prius driver. It’s small, seating only 4 because of the T-shaped battery, and from early reports has poor visibility and trunk space. It’s not terribly efficient. I just can’t get away from thinking that this damned thing was made to fail. It has all the hallmarks of being cobbled together at the last minute, and doesn’t seem to be a very worthwhile effort. As much as I believe that EVs, hybrids, and PHVs are the way of the future, so far I’ve found little to recommend the Volt.

But just because the Volt doesn’t have the efficiency to be worthwhile doesn’t mean that’s going to be the case for EVs in general, or PHVs for that matter. And hybrids already make both financial and environmental sense.

One of the concerns that just won’t go away is the batteries: now with plugging-in the batteries are going to go through deeper charge/discharge cycles. Plus they’re bigger and more expensive, so the question people ask is what’s the risk of a battery failure? For Toyota, the last reported figure was less than 1 in 40,000 odds of a failure in the 2nd gen battery packs (currently on 3rd gen). These things are basically going to last the life of the car, and have a lower failure rate than an equivalently expensive part in a gasser (like a transmission going, cracking a cylinder head, etc.). Cabs have gone over a million kilometres with no serious degradation in battery life, and the first of the first gens are now about 15 years old and haven’t started dropping like flies from pure calendar age. The batteries are not a risk factor, and even then the cost is not steep since more are piling up in scrap yards from collisions than are failing otherwise. Ford recently announced their numbers and they’re even better: the odds of a battery failure are 1 in 8.5 million.

Now as incredible as that is, that’s for tried-and-true Ni-MH batteries, like the ones in the Rav4EVs that are also still going strong in deeper-discharge EV mode. The Volt has a new Li-ion battery pack, so we have yet to see if those figures will carry over (plus of course, the GM quality factor).

Ridiculous Article on EVs

January 12th, 2012 by Potato

Netbug sends along this opinion piece on electric cars after discussing it with his family, saying “I’m sure the math is sound, but I think he’s missing the point… Can you refute the article articulately or am I way off base?”

I’ve only read it twice, but I’m sure he’s missing the point. Moreover, I’m not sure the math is sound. He uses a particularly bizarre way of figuring the cost/savings of EVs, and even then gets his figures wrong.

Let’s start with his assumptions about fuel economy for gas cars. Note that he does not spell them out. To maintain consistency, through most of this I’ll be using US units, figures, and data sources.

A CAFE compliant new car will offer an average fuel economy of 33.3 mpg while a CAFE compliant new light truck will offer an average fuel economy of 25.4 mpg.

Well, right off the bat, that’s untrue. CAFE is not a measure of any particular car, it’s a fleet average, and it includes the contribution of electric vehicles and hybrids (plus some voodoo about ethanol credits). Moreover, it uses a modified scale/test procedure: 33 MPG for CAFE terms is more like 25 MPG on the current EPA test, and even lower real-world. Look up the EPA ratings. I picked a Ford Focus (compact car): it’s at 28 MPG combined. Even compact cars aren’t at the numbers he’s using. According to Natural Resources Canada, the average fuel consumption of the current light vehicle fleet is just under 11 L/100km, or 21.8 MPG.

Now, there is room to quibble there: that’s for a range of cars from new to 10+ years old, whereas new cars will be slightly better. Still, your comparison car is not going to be getting 30 MPG, and especially not when you consider that you should be comparing to the city mileage since EVs are for urban settings.

At 30 mpg, the owner of a new light duty vehicle will consume about 420 gallons of gas per year

He didn’t go through his math, but let’s go backwards: 420 gallons * 30 MPG = 12600 miles/year. That’s probably a reasonable figure to use (I’ve seen 15k mi as more common, but that may just be a case of rounding to a prettier number; not sure what the figure is for those with daily driving commutes). At 22 MPG, that’s more like 572 gallons.

Then he goes to another paper, and somehow gets that electrification doubles the cost of the car (from $19k to $39k). That again is a pretty suspect analysis. For instance, a general rule-of-thumb is that the engine & transmission are 20-40% of the value of a car, yet that paper somehow found that the engine & transmission were just 13% of the cost of a gas car. Moreover, we can buy EVs on the market today that do not cost that much — the Nissan Leaf is “only” $35k (USD), the Prius plug-in has a gas engine and a plug-in battery, is larger and nicer than a $19k comparable car, and is only $32k (USD). Indeed, from looking at US manufacturer’s websites, a compact car with automatic transmission is more like $21k than $19k, and that’s still not adjusting for non-driving features.

The ultimate obscenity is that a conversion from gasoline drive to electric drive will not reduce the total amount of energy used in transportation.

This statement is unsupported by the author, and with good reason: it is patently false. Half the reason to go to electrification or hybridization is the efficiency gain: electric motors are just simply more efficient at turning chemical potential energy into kinetic energy than internal combustion engines. Plus, you can shift the source of that energy from oil to natural gas, hydro, or other renewables.

So, if we re-do his analysis with more realistic numbers (all US figures), we have that the incremental cost for an EV ($21k to $35k) is $14k. That’s saving 572 gallons of gas/year, or 14.1 bbl/yr, or 212 bbl/car lifetime. That works out to a cost of $66/bbl. Which is less than the current cost of oil. Now, this is not the method I would have chosen to make a comparison, but even using his analysis the point he’s reaching for isn’t made.

He also forgot a lot of factors that make EVs a better choice.

Direct financial ones like: Less mainenance cost (no oil changes, spark plugs, timing belts, water pumps, brake pads, etc., etc., etc.), lower fueling costs (oil is an expensive and volatile commodity).

Plus, environmental factors like: Less total pollution (even on a 100% coal power source, an EV is arguably cleaner than a conventional car, and most places are only a fraction coal-powered); pollution shifting (no more smog in city centres!); self-reliance (you can make your own electricity if you’re a doomer, whereas refining your own gas is hard; plus, the cars are quiet and good for sneaking up on zombies). And that efficiency gain.

So right now, going with an EV is close to break-even (though maybe just one the far side). You get all the nice stuff on top of that, but it’s also new, unfamiliar technology. That’s why the subsidies come in: to help make it not only better, but cheaper, to get the ball rolling.

I’m sure the author was cautious in his conclusion, pointing out that his back-of-the-envelope paper, pencil, and calculator analysis could have some holes, that it’s a bit of a strange approach to take (cost per barrel of oil offset?) and that EVs might in fact make some sense…

Electric drive proponents are selling a house of cards based on fundamentally flawed assumptions and glittering generalities that have nothing to do with real world economics. Their elegant theories and justifications cannot withstand paper, pencil and a four function calculator. Shiny new electric vehicles from General Motors (GM), Ford (F), Nissan (NSANF.PK), Toyota (TM), Tesla Motors (TSLA) and a host of privately held wannabe’s like Fisker Motors and Koda are doomed to catastrophic failure. Their component suppliers will fare no better.

Oh wow, he really got the whole foot in there, didn’t he.

Now, as usual, I’m not saying that EVs are going to suddenly take the market by storm: there’s a lot of range anxiety to conquer. They’re not suitable for everyone. But no car is. There are about 1.5M families in the GTA alone; of those, about half have 2 or more cars. I’d estimate that something like 15% of those have (or could easily have) one car that is largely used just for commuting within the GTA — in other words, there’s potentially a market for about 100k EVs in the GTA alone. It’s a niche, but a respectably large one; one that’s worth developing. The economic argument may not be a slam-dunk on its own, but it’s a far cry from a house of cards doomed to catastrophic failure.

Expensive Advice

December 31st, 2011 by Potato

There is some truly bad advice out there on the internet, some of which can be expensive. I see a lot of it in the fall as pertains to the seemingly mandatory “list of things to do to your car to get ready for winter” articles pop up. One particularly egregious example encouraged people to rotate their tires (but not change-over to winters), change their coolant every year (most cars only need a change every other year, and many newer cars have formulations that last 5 or more years, and a coolant flush isn’t all that cheap), add fuel line antifreeze with every fill-up (winter gas eliminates this need, and when have you ever heard of someone getting a gas line freeze-up in the last 10 years?), and get an oil change and inspection.

I put up my winter driving prep list last year, and as expected the number one tip was get winter tires. I should have bolded it then, too. The up-front cost is a little high (few hundred dollars, either for a dedicated separate set, or the incremental cost over all-seasons to get winter-rated all-weathers), but well worth it in terms of safety, and also saving some wear on your summer set of tires and rims. You can even get a discount on your insurance from many providers.

Then along comes Marianne, who earlier in the fall was on a tight budget, and somehow prioritized rustproofing, an inspection, detailing, and winter mats over a safety feature like winter tires (and don’t get me started on other things she decided were better uses of her money than snow tires). She complained of the cost, and of only using them for 4 months (though Nov, Dec, Jan, Feb, Mar seems to be 5 months to me, and possibly 6 if you do your driving at night and it’s chilly through half of October and April — and fully half the mileage if you do more trips by bike in the summer).

That attitude may have changed as she now relates to us a harrowing tale of a near-miss spin-out on snow-covered roads over the holidays.

I will say it again: I know people with all-season tires who don’t think the cost of winter tires is worth it, and people with winter tires who think it is worth it, but no one with winter tires who thinks it’s not worth the cost. They give you such a large margin-of-safety on cold and slippery roads, it is easily worth the few hundred bucks.

The other things on these perpetual winter driving lists are good, but can be expensive advice. Winter tires should be the #1 point on all those lists, and despite the up-front cost, are the least expensive advice there is. I won’t come out and say that regular inspections are a bad idea, but if there’s nothing suspicious happening with your car, the money is better spent elsewhere. For a car that’s driven regularly in most of the populated regions of the country, a gas antifreeze additive is a waste of money. Coolant is good for a few years; if you need to, you can push it a little bit (and it’s much cheaper to get tested than indiscriminately replaced). Rustproofing has its advocates, but if expenses have to be prioritized and deferred, it can be put off until the spring, or even for a few years. And as much as I love rubber winter mats — I leave ’em in all year long — no one ever died of salt stains on their carpet.