Here’s the latest reader question, along with my reply!
Ron asks: I always read your articles on Lew Rockwell, and I enjoy them. I have a question: Lately, I’ve been wondering why modern cars get such poor fuel economy. So then I got to thinking that maybe the fuel injectors are not properly atomizing the fuel; resulting in an incomplete burn. So I looked at a Bosch fuel injector, and noticed that indeed it only has four simple ports; and that there is not an atomizer on the end. It just shoots four liquid streams.
But then I realized that if there were actually a poor burn in the combustion chamber, then gasoline fumes would come out of the tailpipe; and the car would fail the emissions test. So there must be a complete burn. But does a complete burn automatically mean that the fuel was used wisely? Maybe not. If you raise the compression of the engine, and shorten the stroke of the pistons, then you can deliberately waste kinetic energy; and still get a clean burn. So in other words: Could a short stroke mean that all of the expanding gas is not being fully taken-advantage of? And could this be compensated for with higher compression, to ensure a complete burn?
My reply: There definitely should not be liquid streams! Keep in mind the fuel is pumped through those injectors at high pressure (extremely high pressure in a DI system) and rest assured that unless the injector/pump is defective, the fuel is atomized into a fine mist.
As far as why the mileage of new cars is so mediocre – which is the word I’d choose:
One, the average new car is much heavier than its counterpart of say 30 years ago. Two, it is much more powerful than the average car of 30 years ago. Consider that a typical mid-sized family car such as a new Camry offers a 300-plus horsepower engine and is quicker and much faster than most classic-era V8 muscle cars. Even four cylinder engines routinely make as much power as V8s did back in the ’80s.
But there is another factor: Ethanol. Most “gas” sold in this country is E10, or 10 percent ethanol. Ethanol contains less energy than the same volume of gas, so the effect is a reduction in fuel economy. Most people are unaware of this “hidden tax” – which is paid for the benefit of the ethanol lobby.
On the rest: High CR engines are usually more powerful and efficient, but there are many variables in play. The main reason modern cars are lackluster when it comes to the mileage they deliver is they’re simply very heavy – and have powerful engines – which would be okay if we were allowed to use them!
But we live in this odd scene – cars never more powerful and capable; traffic laws still more or less what they were in 1970. And people browbeaten to never use the power/capability of their cars.
Yeah, it makes my teeth ache, too!
Got a question about cars – or anything else? Click on the “ask Eric” link and send ’em in!
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