Keep the design simple (KIS). Fewer parts equals less cost. Fewer parts means fewer parts that can fail. It’s not just in the assembly. You’re parts need to be inventoried, designed, manufactured and paid for.
In this respect, I am not a fan of hybrid automobiles. In my opinion, they are unnecessarily complicated. A small gasoline engine charges a bank of batteries, followed by the battery driving electric motors. Not only that, many of the so-called hybrids utilize a direct drive transmission from the gasoline engine to the wheels, adding even more complication.
I like diesel engines, especially the new, small-block engines for compact cars. These designs are nothing new. In the late 1970s, Volkswagen produced the diesel Rabbit. It achieved efficiencies of 50 miles per gallon or better. The new crop of small diesel engines are easily besting the designs from 30 years ago, with efficiencies equaling and exceeding 60 miles per gallon.
Those fortunate enough to have traveled to Europe in the last 20 years may have had the opportunity to drive automobiles equipped with these engines. The fuel economy these automobiles are capable of are considerably higher than that achieved by gasoline-powered engines in the United States. Yet, for reasons I do not fully understand, automobiles equipped with these small diesel engines are for the most part not available for purchase in the United States. I find this rather ironic and puzzling. It’s the only vehicle I would purchase new.
My automobiles for daily use – for the last 25 years – has been the Honda Civic and Accord. Over the years, my family has owned five of them, four of which we still own. All were purchased used, and kept in good running condition and have proven to be reliable, safe, and efficient. Fuel efficiencies vary between 35 to 40 miles per gallon or higher, depending on the time of year, how it is loaded, and the length of trip. Until efficiencies get into the 50 to 60 miles per gallon range or higher, I have no incentive to purchase any other vehicle, let alone a new one.
Several automobile manufacturers such as Ford, Honda and Volkswagen have manufactured highly efficient, small displacement diesel engines. Some are even turbocharged, which from a weight standpoint can make a great deal of sense by substituting engine bulk for a small, reliable air compressor-which is what a turbocharger is – that uses exhaust system energy to generate more power for a given engine displacement. The energy within the exhaust gas stream would be wasted anyway if not used to drive a turbocharger. Efficiencies improved to such an extent that these engines are considerably more efficient then the gasoline-electric hybrids.
There are other metrics besides mileage. Total operating cost has to be calculated which includes purchase price and financing, insurance, depreciation, maintenance, longevity, etc. Replacing the battery packs every few years in hybrids has got to be painful. So I will not be a hybrid auto customer any time soon. My old Civics will suit me fine.
Norman T. Neher, P.E.
Analytical Engineering Services, Inc.
Elko New Market, MN
www.aesmn.org