Simanaitis Says

On cars, old, new and future; science & technology; vintage airplanes, computer flight simulation of them; Sherlockiana; our English language; travel; and other stuff


AUTOMOBILE BUYERS want it all—and enthusiasts want even more. Performance galore, gizmos galore, glitz galore. And then there are conflicting government regulations requiring added safety features combined with increasingly stringent mpg standards.

Fortunately, the world’s automotive engineers are a talented lot.

Several years ago, John German of the International Council on Clean Transportation offered the thesis that automotive fuel economy continues on a trend of improvement despite increased weight and horsepower.

An article in Automotive News, January 13, 2014, “Lean Muscle,” details the technical achievements that make this possible. I’ve put these data from the U.S. Environmental Protection Agency into graphical format.


Automotive trends over the past six years are generally encouraging. Source: U.S. EPA.

What with their enhanced features of safety, comfort and convenience, modern cars have curb weights averaging around 4000 lb. There has been modest fluctuation over the past six years, but hardly any significant trends.

On the other hand, average horsepower has risen from 219 hp in 2008 to 230 hp in 2013. And, at the same time, fuel economy has also jumped from 2008’s average 21.0 mpg to last year’s 24.0 mpg.

This magic came about through automotive technology, with increasing penetration levels of three features: automatic transmissions with six or more forward speeds, gasoline direct injection and exhaust turbocharging.


Six years of technical progress are evident in the percentages of cars featuring enhanced propulsion.

Modern automatic transmissions are well beyond the pure 2- and 3-speed planetary arrangements of traditional slushboxes. This website’s “Tranny Talk,”, offered technical reasons of how a higher multiplicity of gears makes engines more frugal. Its reporting of the “Bosch eClutch,”, gives succor to the utterly shiftless lot. Before long, the criteria will be changing to eight speeds or more.

Direct injection brings diesel-like precision of fuel delivery to the gasoline engine. Because of complexities and cost, GDI adoption rates have been moderate. But the trend is clear; in time, all gasoline engines will be direct-injected.

Forced induction, whether through exhaust turbochargers or mechanically-driven supercharging, offers the promise of enhanced power on demand (of one’s right foot).

On the other hand, er… foot?, the more forced induction is applied, the more fuel is consumed.

A small turbocharged engine can certainly be calibrated to achieve better mpg numbers in EPA testing than its normally aspirated counterpart of larger displacement. Whether this translates into benefits in the real world is a matter of conscience—and one’s right foot. See this website’s “Turbo Foot?,”, for an analysis of this matter.

What about hybrids and battery electrics? They are the record-holders in EPA results (for example, the Scion iQ EV’s 121 mpg-equivalent; the Toyota Prius hybrid’s 50 mpg). However, even with hybrids, their meager numbers of sales barely tickle overall averages.


Hybrid sales over the past six years have been steady, but modest. Sources: for 2011 – 2013; U.S. Dept. of Energy for earlier data.

Though the number of hybrid choices increases each year, their sales penetration is still a niche market. See “State of the (Hybrid/EV) Union,”, for market profiles. Pure battery electrics are even of less significance overall.

No matter, though. The world’s talented auto engineers have us covered, whatever our proclivities. ds

© Dennis Simanaitis,, 2014

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This entry was posted on February 22, 2014 by in Driving it Today and tagged , , , , , .
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