Priuschatters help me respond to this guy

[bredekamp]

Hi all,

This is the winning letter in the latest copy of Popular Mechanics SA. I would like to respond, but would very much appreciate your input and insights. What I need are factual points of logic where I can nail this guy. I'm not convinced he is entirely correct or fair. How would you respond? I intend signing the letter as:

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MR AJ BREDEKAMP
Webmaster: My Prius.co.za
with the kind assistance of the priuschat.com community
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The guy didn't even get the name of the battery right....Common troops!

There's an initial response here:

Prius Blog

[jayman]

A 21 year old Corolla in South Africa? Let me guess, it was designed to run on leaded gasoline with no emissions control whatsoever.

Even present SA "emissions control" lags far behind the EPA

Along with correcting the chemistry that letter writer used, why not bring into account the far, far lower lifetime Prius emissions of toxic emissions like CO, NOx, PM, NMOG etc

Also be prepared if anybody mentions the "moonscape" around the nickle mine at Sudbury, Ontario, Canada. Hint: the British paper that splashed the "news" from a clueless American college student - who also published rants in approval of raping women and harsh narcotics - had to completely retract their article after discovering the college student had made up everything

Search around the site here. Plenty of stickies that also challenge the Hummer vs Prius argument too

[Mike Dimmick]

A 1988 Corolla was probably an E90, with the 2E engine if 1.3L. A car that old was carburetted, not fuel-injected. Carbs can be tuned for a lean mixture, which could well have been done on this car.

Petrol burns most cleanly, producing least CO and unburnt HC emissions, and least NOx formation, at the stoichometric ratio of 14.67:1. However, engines actually run best about 10% richer, consuming more fuel and producing more CO and unburnt HC in the exhaust.

Petrol has a very wide range of ignitability, though. It is possible to adjust the mixture quite a lot leaner and still have it ignite properly. It comes at the cost of much greater ignition temperatures (which are related to the relative proportions of fuel and oxygen molecules) which cause greater formation of nitrogen oxides, NOx. (Basically some of the energy goes into separating nitrogen molecules into their separate atoms, which then preferentially combine with some of the oxygen.) Some engines use concentrations as low as 65:1.

NOx is a large contributor to smog, which is why it's been regulated. I note from here that SA started controlling emissions from 2005 only, requiring only Euro 2 standards from the start; however, even Euro 2 could only be achieved using catalytic converters.

Three-way catalytic converters strip the oxygen back off the NOx and combine it with the CO, and burn off the HC, to vastly reduce those toxic emissions. They can only work effectively if the raw emissions are minimized, by running at the stoichometric ratio; richer than the lowest fuel consumption at which the car will run. See this discussion of air-bleed devices. Modern cars have very sophisticated ratio monitoring sensors to ensure that the car runs as close to minimum as possible.

I suspect that the writer of this letter has dialled back the mixture screw on the carb to reduce the fuel consumption, and is emitting large amounts of NOx. A 1988 Corolla in the US, with the 1.6 litre engine, got 30mpg in the city test, 35mpg on the highway test on the then-current test programme. The US had already been regulating emissions for 18 years, and these vehicles were equipped with catalysts. On the same test, 16 years later, the 2004 Prius achieved 60mpg city, 51mpg highway. (Source: US EPA, fueleconomy.gov)

[toxicity]

I can't really find any major fault with what that guy has written. Cars weighed less in the 80s due to less safety features, and driving an older car, even a gas guzzler, will have less of an effect on the environment than driving a new car;

There are only two points I would bring up:

1) The "superfluous" gadgets he talks about are not, in my opinion, superfluous; I understand South Africa can get quite hot during the year, and I would be damned if I were to live and drive there without air conditioning.

2) The rated fuel economy of the Prius is only under the conditions that the regulatory agency tested them under; in reality, due to the hybrid design, the engine can temporarily shut off; this leads to situations where you can achieve a very high efficiency of fuel consumption, and yet no one seems to ever take this into account; however it is obviously not ever made clear to anyone other than experienced Prius drivers.

The internal combustion engine is at its most efficient design, and that is why Toyota paired an electric motor + battery with it to coax some better fuel economy. If people want better fuel economy than around 36mpg from 87 octane fuel, they have to pulse-and-glide, otherwise their engine will just yield the same old 36mpg from the "constant-powering"-style of driving.

The problem is that very few people are aware of gliding, and fewer people will want to engage in it, because they find driving to be dangerous enough without driving even more unpredictably. What we need before anything else are some attitude changes amongst drivers before we can hope to achieve a higher fuel economy across the "fleet".

The only way besides pulse-and-glide to achieve higher fuel economy, would be to do what, for example, occurs with diesel-electric trains - run the internal combustion engine at their most efficient RPM constantly, and have that usable work converted into electricity, which powers motors at the wheels, to move the vehicle along. I believe Chevrolet is doing just this with the Volt, so that will be interesting to see.

[kenmce]

We need to compare life cycle or carbon footprints - reasonable.

Take cognizance of building a replacement battery every ten years -

Don't know about RSA, but in the USA we have an sufficient supply simply by pulling batteries from cars that have been wrecked. They are cheap and we usually have an assortment available on eBay. The ten years (in the US) is the minimum time covered by the manufacturers warranty, not the normal expected life.

If you'd rather get a new battery from the dealer they can order one. A new battery is made of steel , nickel, lye, copper, a circuitboard and a relay. All of these things are in good supply, are easy to work with, and other than the circuitboard, recycle well.

A Corolla is a good little car, but you can't fairly compare one to a Prius. A more even comparison would be a hybrid Prius Vs. a non-hybrid Camry. They are both four door sedans and are similar in size and comfort level.

It sounds like he makes good use of his Corolla. He should be aware that any time you compare a car with manual transmission against one with automatic transmission, the manual will have a natural advantage. There are less parts, less weight, and less power loss in any manual tranny. Convenience does have a cost. To compare one manual against another or one automatic against another is the correct way to go.

The Prius does have more safety do-dads and standard features than a Corolla, and this does of course have an associated cost. Stripped down low end hybrids should be coming, and one of these would be what you'd compare against a stripped Corolla.

Mr. Rankine is correct that a Prius is not a full and complete answer to all of the environmental problems associated with commuting. It is however a significant step in the right direction and is the "greenest" car that is available to ordinary people. Persons who can use a scooter or bicycle will of course do even better. People such as myself, who live in an dodgy climate, cannot always rely on them.

He is correct that mass transit would be more efficient. Someday I hope we will have it. We will not however have it before I need to go to work on Monday.

Any time you compare the energy or Dollar/Rand cost of maintaining an old car Vs. buying a new car, keeping the old car will *always* come out ahead. It doesn't matter what they are. What he might want to look at is the relative cost of buying a new hybrid vs a new non-hybrid.

Regarding the "higher hybrid insurance premium", we don't have that here. Is he perhaps comparing insuring a brand new car Vs. insuring a twenty year old beater?

The solar cell skin idea is catchy, but the amount of energy that falls on a car is just not enough to drive around with.

[dogfriend]

I have noticed that many people use an unfair comparison, especially those who want to make older tech or diesel tech look better compared to hybrid tech:

They use the best possible mileage obtainable on the highway and compare to the hybrid all around mileage. But, most cars are not used strictly on the highway. So comparing a 45 mpg hwy figure from a diesel Jetta to 46 - 47 mpg for a 2nd gen Prius is not a fair comparison because in mixed driving the Jetta will not achieve that 45 mpg.

It is true that lighter cars get better FE and those tuned very lean can get very good FE. But most people want safer cars and we should all attempt to reduce NOx and other components of smog so we can breathe the air.

[bredekamp]

Thank you for your input. It looks like we can nail this guy on the following facts:
- Emissions, The Prius is ULEV no matter how you slice it.
- An old car will always be cheaper to keep
- A true comparison requires cars of similar weight and size, one petrol, one diesel and one hybrid

What do you think of my comparison here? [best viewed with IE]
Diesel vs Hybrid

I'll compose a response to PM and you can read it and comment before I mail it off. I must get this right.

[patsparks]

I'm sure a Niki would use less fuel than his Corolla too, isn't that a fair comparison?
A Honda 110cc postie bike would use much less fuel than the Niki and you aren't carting around all that superfluous tin ware, who needs all that safety crap anyway? No one ever died from a little rain.

[nameless dude]

This site might prove to be useful:

Is it possible that a Hummer's better for the environment than a Prius is? - By Brendan I. Koerner - Slate Magazine

[bredekamp]

Here's my letter
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Dear Editor,

I refer to the letter "Okay, let's do a few sums" in your April 2009 issue.

The comparison is flawed. The Prius is heavier, larger, safer and has more features than a 1988

Corolla. Yet it still beats the authors best attempt of 5.38 litres/100km.

I own a Prius and use it almost every day. With normal driving I routinely get fuel consumption of 5.2 litres/100km. Normal driving means 110-120 km/h with the air conditioner on.

The issue of emissions is never mentioned. The Prius is rated as an Ultra low emission vehicle or ULEV. This means that it emits extremely low levels of air pollutants compared to other vehicles. With a carburettor and no catalytic converter, the 1988 Corolla will emit considerably higher levels

of CO, NOx and unburt hydrocarbons than a Prius. Even a diesel vehicle with similar fuel consumption to a Prius will emit higher levels of NOx than a Prius in addition to particulates.

By Toyotas own admission it does take more energy to produce a Prius. However they have gone to great lengths to enhance their production process to minimize energy usage and CO2 emissions. Toyota

states that after you've driven a Prius for 20 000 km you're emitting less overall CO2 than a normal car. This break even point is called the Prius effect. The battery is also fully recycled at the end of the vehicles life.

Battery replacement still seems to be a concern for hybrid buyers. Real world data and Toyotas own tests show that the NiMH battery should easily last the life of the car or 290000km. There are Prius taxis in Canada that have done these distances without battery problems. Even if a Prius does need a new battery at 300000km, show me any car that won't need expensive major components replaced at that mileage.

The author is correct that internal combustion engines are as efficient as they're going to get. This is why Toyota paired an electric motor and battery with the engine. The hybrid system allows the engine to run at its' most efficient RPM range, while the battery can store excess energy or

provide extra energy as required. By using the motor as a generator, braking energy can also be captured and stored instead of being wasted as heat.

I was surprised at the authors statement,"cars have become burdened with more weight in the form of safety features and superfluous gadgets". Since when is safety a burden? The Prius has a 5 star EURO NCAP rating. Does the authors' Corolla have an air conditioner, and how would that affect his fuel consumption?

The author is absolutely correct that people should make greater use of bicycles and public transport, provided acceptable public transport exists.

Finally, a potential car buyer should indeed weigh the cost of switching to a hybrid vs. keeping an existing vehicle on the road. Unfortunately keeping the existing car will almost always win because of cost. It is better to look at the complete package and ask yourself which is better for the environment, my needs and my wallet.


Mr AJ Bredekamp
webmaster: myprius.co.za
with input from the Priuschat.com community


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