Wednesday, April 18, 2012

A Diesel Powered Earwig And the Chevy Volt

This morning when I was going through all the mail from all the various accounts I had, and deleting out all those spam from Canadian Pharmacies that seem to exist only as a scam, I stumbled across a comment on one of my earlier posts. 

I had written here about a picture of a Chevrolet Volt being charged up in Fort Lauderdale at a wall socket.  There was a comment at the bottom about Chevy releasing an SUV in India based on the same technology. 

Good idea but does everyone need an SUV?  Sure, they're roomy and all, but everyone does not need one.  If we did, we'd all be driving one.

I do think it is an interesting application of technology but I am left with two problems with it from a "functional" view.

First, the biggest problem that it has is that big battery pack.  It's big, it's expensive, and you are carrying along a giant pile of batteries resembling the sale bin just before the Xmas shopping binge.  You need a lot of D cells to power your toys and many of those packs are similar - a lot of commodity rechargeable batteries wired together.  Get into an accident, they will burn if the pack is broken in the right way.  The other problem with that battery pack is that they wear out.  Cells will wear out after a couple hundred to a couple thousand charges.  The packs are typically not built to be repaired.  Where do the packs go after they've been worn out?  Recycle what you can and landfill the rest.  Not great, but better than the pollution of all of that gasoline.

Second the Volt has a gasoline motor to run the generator to top off the battery pack.  It isn't a large motor, only a 1.6 Liter.  It isn't used to drive the car until it gets into conditions of high speeds or heavy load.  Since it is a generator, you want to have the smallest motor that is available to do the job.  The higher the efficiency of the motor, the lower your fuel consumption would be.

That raises the question:  Why a 1.6 Liter Gasoline Motor? 

Why not Diesel?

Volkswagen has an effective comparison in their offerings.  Using the US Government's numbers, you can ask why is it that we're using a Gasoline engine at all?  Typically, and those figures bear out the rule of thumb, for the same size motor, a given Diesel motor will be 1/3 more efficient than a given Gasoline model.  Bearing in mind that the power output of a Diesel is slightly different (More Torque vs Horsepower), they are effectively interchangeable, especially when you have a turbocharger on them. 

So if you have a 95MPG Equivalent Volt, would that mean that dropping in a Diesel motor will you get 130 MPG?  Perhaps.  The EPA is notoriously inaccurate in measuring the MPG of a Diesel car.  That Jetta that is rated at 30MPG regularly gets 40MPG in real world numbers.  It is a "Clean Diesel", which means if you were standing behind it, you may notice a slightly different smell but it wouldn't coat you with soot like the older cars may have. 

If you drive it gently, a Jetta TDI has been seen to give 50MPG on the highway.  In the Hypermiler communities, it raises the question of whether you need a hybrid at all.  The real world numbers of a Jetta TDI tend to be almost as good as and in some cases better than that of the darling of the Green World, the Toyota Prius. 

So press releases aside, because that comment in my older posting reads like one, I still am confused as to why we don't have more Diesel in this country.   The memories of the old Oldsmobile 98 Diesel are still out there, but fading.  It's time we bury that, and move on.  With $4 a gallon gas and the prediction of gas hitting $5 a gallon before the end of this year, this country needs every extra MPG it can get. 

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