Twenty degrees or -20 degrees, turn the key and your vehicle starts right up and runs perfectly. That is the case for most of us. Some of us even start the car from inside the house. Spoiled brats!
The miracles of modern science.
Fifty years ago getting your car started required a little more work and knowledge. Pump the throttle and or set the choke and turn the key. Engine starts and runs but rather quickly. You couldn’t just drive away. Wait a little bit. Blip the throttle. Then drive away.
They don’t build them like they used to. I don’t think many of you would really want to go back in time. I guess you would have more time for Twitter, Instagram and Facebook while you waited for your vehicle to settle into a nice smooth idle so you could drive away.
The person in charge of how your vehicle is supposed to start and run is called a calibration engineer. Lately, I have gained a great deal of respect for that person.
My latest science project is allowing me to delve into the life of a calibration engineer. I am currently the master of my own calibration on my V8 engined SUV. Can I make it startup and idle at 20 degrees, just as well as at -20 degrees and anywhere in between?
At this stage my success is fleeting and a relatively slow plod but I do sense progress. The modern day fuel injection and ignition systems are computer controlled. Inputs like air temperature and engine temperature are read into the computer. The key is turned, the starter rotates the engine. The engine begins to rotate. Air is ingested. A calculated amount of fuel is supplied. A spark is generated at the spark plug. The time of the spark is another critical calculation.
Get the timing of the spark, the amount of fuel relative to the amount of air just right, combustion proceeds and the engine begins to rotate on its own. The key is released from the start position the engine continues on its own overcoming friction’s tendency to pull it to a halt. After start enrichment and warm up enrichment keep a cold engine running. Again the calibration engineer has set the outputs of spark timing, fuel injection, and airflow to keep the engine running just so.
Once roughly dialed in I can start my vehicle at most temperatures but getting to the point where it starts and runs at the twist of the key is a series of somewhat educated steps and trial and error. There are essentially only two cold starts per day. First thing in the morning and then after work. The variety of temperatures is in the hands of Mother Nature.
Once all the data is set it is locked into the computer of your car. The cold start calibration is set.
When your vehicle does not start and run as it should don’t blame the calibration engineer. Something else has gone amiss. It is the job of your mechanic to determine the cause.
Worn spark plugs, leaking fuel injectors, low fuel pressure, restricted airflow, a weak battery, improper engine temperature measurement are only a few of the possible problems that result in a less than perfect or no start at all.
Getting your vehicle up and running again can be just as challenging for your mechanic as it was for the engineer who calibrated it.
Trail’s Ron Nutini is a licensed automotive technician and graduate of mechanical engineering from UBC. E-mail: firstname.lastname@example.org