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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Electric cars get 81% better miles per gallon acre

(photo credit rsgranne and davipt via the Flickr Creative Commons license).

[Update: This article is crossposted on Grist.]

From a study published in this week's Science Express ($ub Req'd):

Bioelectricity produces an average 81% more transportation kilometers and 108% more emissions offsets per unit area cropland than cellulosic ethanol…

Given the limited area of land that is available to grow biofuels crops without causing direct or indirect land use impacts, bioenergy applications should maximize the efficiency with which a given land area is used to meet transportation and climate change goals.

Bioelectricity is the act of making electric power by burning biomass for boilers or turbines instead of fossil fuels like coal.

In a nutshell the study says that an electric car using electricity generated by burning biomass will get 81% more miles per acre than a car using cellulosic ethanol. That is equivalent to improving the purported American average of 24 mpg to 44 mpg, which coincidentally is also the improvement achieved by the Prius and Insight.

I touched on this subject in an article titled Misplaced Priorities over on Grist in last year. Imagine replacing the coal in the above photo with corn or wood or hay. Something has to give.

Corn ethanol was also part of the study and as you might have guessed, faired much worse than cellulosic. Not studied by this paper are environmental impacts and costs:

Specifically, the competitiveness of biomass ethanol depends on the cost of petroleum, whereas the competitiveness of biomass electricity depends on the cost of coal, wind, hydro, solar, and nuclear.

Which of the above energy sources will be increasing in cost and which will be decreasing?

The study looked at pure internal combustion cars and pure battery powered electric cars. It did not look at plug-in hybrids, which would eliminate range constraints imposed by today's battery technology.

The paper also said:

Two leading technology developments, cellulosic ethanol and electric vehicle batteries, provide alternative pathways for bioenergy-based transportation. Biomass can be converted into ethanol to power internal combustion vehicles (ICVs) or converted into electricity to power battery electric vehicles (BEVs). It is uncertain which pathway could reach technical and economic maturity first. The cellulosic ethanol pathway benefits from commercially available flex-fuel vehicles but requires significant investments in infrastructure as well as technology advancements to reduce costs for energy conversion. The bioelectricity pathway shows promise in existing distribution infrastructure and emerging commercial offerings of battery electric vehicles that meet technology challenges of range, cost, and charging time. Electricity produced from biomass is a near-term renewable energy source that can be implemented with biomass boilers, Integrated Gasification Combined Cycle (IGCC) power plants, or co-combustion with coal.

What we have here is a battle forming up between increasingly electrified transport (hybrid--plug-in hybrid--fully electric) and corn ethanol powered internal combustion engines (cellulosic is and will probably always be just five years from economic viability). One side is championed by consumer demand being met by market forces and the other side is championed by our politicians who force us to pay to turn our own food into fuel and then pour it down our throats. These are the same politicians who subsidize oil with one hand and its competitor, biofuels with the other. If it hasn't dawned on you yet that our politicians are not capable of solving complex problems like this, maybe its time it did. Take matters into your own hands. Make your next car purchase a hybrid, plug-in hybrid, or full electric when they arrive (on dealer lots next year).

The Renewable Fuels Association is going to have its hands full debunking all of this peer-reviewed rubbish being published in rags like Science (see here and here).

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