– by Julian Sale –
How times have changed!
I loved the automotive courses I took in high school. I built my first V8 in my buddy Marty’s garage when I was 17. Everything was pretty simple, no electronics, no fuel injection, simply mechanical stuff – no problem. Technology has taken what is nothing more than an air pump (internal combustion engine or ICE) and installed sensors to monitor every aspect of performance and economy. Then its computer makes minute adjustments continually for the perfect tune. In the case of an ICE, the basic principle is unchanged from years past; suck in measured doses of air and fuel, squeeze and compress them, light the mixture on fire with a bang, and blow the exhaust out of the engine.
Before 1986, many cars had carburetors, and the result was pure simplicity. You push the accelerator pedal, and a linkage or cable opens the throttle. The accelerator pump squirts raw fuel into the venturi in the carburetor, and it gets sucked into the engine to be burned along with a fine mist of fuel created by the air rushing into the engine through the carb. The ignition system lit the mixture with precise timing, and the valves opened and closed as necessary, and the cycle completed, and repeated. Voila, your engine is running. And it’s at the mercy of your right foot.
Modern ICE’s aren’t like that. We have no cable, no linkage. We fly by wire. Today, a depressed throttle pedal sends a message to your ECU (engine control module) which is considered along with coolant temperature, ambient air temperature, rpm, load, and even the sound of the engine (knock sensors) before your ECU determines how much fuel the electronic pump and injectors will supply. Pressing the accelerator in a modern car is not “hitting the gas.” It’s asking politely for an algorithm to allow your ICE to spin faster, provided all the planets and stars line up. Why the go-between? A couple of reasons, like fuel economy and reliability. It’s hard to waste fuel or over-rev an ICE that you can’t really control.
Essentially, we have a nanny under the hood now. She’s watching, and ensuring that we are driving responsibly – from a mechanical point of view. Jeez, I just got started, and I’m out of space again. For more useless automotive trivia, visit me on twitter @vicautobroker.
See you next time, Julian Sale.
