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Friday, December 30, 2011

Chevy Volt--Mechanical Engineer Perspective

Chevy Volt Plug-in Hybrid

1926 Model T tractor conversion

I took the above photos at the county fair this summer. The Volt and Model T tractor conversion are both the result of ever present engineering compromises that tend to be exacerbated when designing a multipurpose machine. With the Model T kit you could convert your car into a tractor for planting season. Although the idea of combining two machines into one was appealing, the kit was not very successful because the resulting tractor preformed poorly compared to real tractors.

With the Volt, you get an electric car and a gasoline car all in one. The electric car is inefficient because it has to lug around an inert gasoline engine, fuel tank, fuel pump, fuel injectors, radiator, oil filter, muffler, catalytic converter and other attending air pollution devices for when you run out of charge.

The gasoline hybrid mode for the Volt is inefficient because it has to lug around a large depleted battery and  two large electric motors in addition to the gasoline motor and its attendant hardware. This explains its dismal 33 mpg performance for a four-seat gasoline hybrid. The lack of a fifth seat is yet another compromise.

Another example of engineering compromise would be those pocket knives that combine just about anything you can imagine into one handy package. However, none of the tools contained in that knife work nearly as well as a separate tool designed for a specific use. Picture trying to measure something with that knife's ...measuring fish hook remover thingy. This explains why car mechanics and carpenters have thousands of dollars worth  of tools at their disposal instead of just one of these babies in their pocket.

Volt owners can also expect higher than average maintenance costs (lower than average reliability) thanks to the complexity of having two drive systems--an internal combustion engine driving an electric motor that in turn drives yet another electric motor.

Powered by electricity without being tethered to electrical outlets, the Volt does everything a great car does ...?

True to America's modern corporate culture, GM attempted to baffle consumers with BS rather than give them a product that earns its market share with superior engineering and performance (like the Prius and Leaf). To this day, journalists are still lumping the Volt in with electric car reviews instead of with other plug-in hybrids. GM's marketing machine had managed to convince the public that the Volt is an electric car. The latest commercials are an attempt to cool the hype because a small consumer backlash was growing ...not to mention Chevy needed a comeback for this Nissan Leaf commercial (look for the Chevy Volt in it). The gullibility of the American public isn't boundless after all.

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Sunday, December 4, 2011

Animal Liberation and Climate Change

I recently concluded a comment field debate with a member of Animal Liberation of South Australia over at Brave New Climate. It's a good article and well worth a read. I made a few critiques in the comment field which blew up into a full scale debate. Go have a look if you've nothing better to do.

I don't disagree that livestock is doing tremendous damage to the biosphere and I wish more people would look for answers instead of continuing to rant about the problem. I suggested that his proposed solutions (taxation and education) were woefully inadequate. I also disagreed with some details in his argument. The truth is that eggs, dairy, and meat add variety to the diet of the third world poor who are at risk of nutritional deficiencies because their diet, although possibly adequate in calories, may not be be varied enough. Domesticated animals were humanities original multivitamin. In first world nations the excessive consumption of animal products has become a bit of a perversion.

He mentioned that about a third of all crops are not used for food but are instead fed to livestock. In reality, livestock is a means of processing crops into more varied forms of food. So it's misleading to claim that a third of crops don't go for food. Biofuels are the real danger there.

And to be honest, although we could and should consume a lot less egg, meat, and dairy, it isn't all that much per person when you think about it. The main problem is that there are 7 billion of us doing it. The few cups of brown tainted liquid called tea and coffee we consume every day is also wreaking havoc with ecosystems.

The backbone of his argument is the fact that people can get adequate protein without "meat" if they have enough variety in their diet, which is true for most people today, especially in first-world nations, but somewhat misleading because this argument rests on the assumption that all 7 billion of us have the needed variety and would be fine without "meat."

I pointed out that since meat, eggs, milk, cheese, whatever, are roughly equivalent when it comes to resource use, environmental impact, and green house gas emissions, that it's somewhat misleading to keep using the term "meat." I suggested he use a more accurate phrase. The term animal sourced food (ASF) is commonly used for this. He didn't bite. His second article sticks to meat.

I realized in the course of the debate that I was focusing too much on protein supplied by animal sourced foods and switched to terms involving nutrients in general.

The second installment in this series is now up and his argument has been honed, in part, thanks to our debate. In one of my comments I critiqued one of his sources, "A 124 page paper on child nutrition and not a single mention of protein?"

In his new post we find the sentence:

A 124 page paper called “Explaining child malnutrition in developing countries” by acknowledged experts (yes, from IFPRI), has not a single occurence of the word “protein”.

Not sure how relevant that is. Turns out, there are also no instances of the words vitamins, minerals, fats, or even nutrients in that PDF. Nutrition issues involve a lot more than just protein. Some more food for thought:

"...nutrition programs have shifted their primary emphasis from control of protein deficiency, to energy deficiency, and now to micronutrient deficiencies... ...1) the most important findings of the CRSP were that faltering in height and weight of children occurs early and was not caught up later in life; and 2) the quality of food (specifically ASF and micronutrient content) was a much stronger determinant of nutritional status than was the quantity of food. ...1) growth stunting started at birth (or before) and was complete by 18–24 mo; 2) protein intakes and protein quality were adequate in all three locations as were energy intakes except when a famine occurred in Kenya; and 3) ASF intake was the strongest predictor of functional capacity (such as growth, lactation outcome and cognitive function)..."
See for full quotes in context.

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Photo courtesy of devlyn via Flickr

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