Niagara Gazette

September 12, 2013

TOM'S CORNER: The evolution of the ignition system

By Tom Torbjornsen
Niagara Gazette

Niagara Gazette — Back when I was a young aspiring auto technician, the term “I need a tune up” was uttered quite commonly. It usually signaled that the driver sensed that the engine was running poorly and thus needed the ignition system to be refurbished. In the old days, ignition systems usually consisted of a set of electrical breaker points that were driven by the distributor (which governed the firing of the spark from the ignition coil), a condenser (that acted as an electrical storehouse when the points were open so the electrical charge would not jump or arch back across the points resulting in misfire), a mechanical spark distributor, distributor cap and rotor, sparkplug wires, and sparkplugs.

The way the system worked was really quite simple. A gear drove the distributor either off the camshaft or oil pump. Electricity was fed to the distributor and, as it spun, the points opened and closed making and breaking the electrical circuit between the ignition coil and the distributor. This making and breaking of electrical flow caused voltage buildup within the coil and then the dispersing of a high intensity spark at precisely the correct time delivered via the rotor to the tower on the distributor cap (in precise time) which was connected to a sparkplug wire. This spark would travel down the sparkplug wire to the sparkplug where it would jump an air gap and ignite the compressed, highly volatile air/fuel mixture in the combustion chamber. Thus, the downward stroke powering the engine was created. Simple in theory.

Of course, with any system of mechanical or electrical design, there’s always a weak link that results in failure or poor performance. In this case, the weak link was the electrical points, condenser, distributor cap and rotor. Points would wear out; condensers would internally ground resulting in firing back across the ignition points and ultimately misfire, backfiring, stalling, hesitation, and a myriad of other complications. The insulation on sparkplug wires would break down from extreme heat up and cool down, resulting in voltage leakage and ultimately, cross-firing and what’s called “breakdown under load.” This condition would usually revealed itself under heavy load conditions such as hauling a heavy trailer or load, or just tooling around town and up and down hills with the entire family in the car. Yes, early ignition systems were not without their negative idiosyncrasies.

Then electronic systems came along with their solid-state design. Characteristically these systems offered better performance overall. However, they were not without their own special set of problems. They were affected by engine heat and consequently prematurely failed, not giving a clue as to when they would leave you stranded. As time went on, the electronic systems got more complex and were able to monitor the

engine environment and make adjustments for changes that occurred. This started to look pretty good to engineers, especially with respect meeting EPA (Environmental Protection Agency) standards and tailpipe emissions. However, there was still one hurdle to overcome … the ability to make “on-the-fly” engine performance adjustments while driving. Then came C.C.C (Computer Control Command) from GM that was the forerunner of today’s quite advanced distributorless ignition systems.

Now engine commands could be monitored and adjusted while in operation through gathering real time information from various sensors located throughout the engine. Sensors for coolant temperature, exhaust oxygen, airflow, temperature and others varying conditions. These sensors provided the necessary information for the computer to measure what was going on within the engine at any given time and make the necessary adjustments to maintain optimum engine performance.

As engine management evolved the need for highly trained technicians, sophisticated diagnostic and test equipment, computerized information systems, and advanced diagnostic strategies have become paramount. Carmakers have full time technical people in the field collecting data on the development of technical trends in the automobile industry. Last year, while I was at the New York International Auto Show in NYC, I had occasion to speak with the technical rep for the Eastern Seaboard for Chrysler. He told me that his job entailed traveling around his territory from dealer to dealer collecting data on specific repairs and malfunctions in an effort to create a database for dealerships and technicians across the country to draw from in an effort to repair problems that pop up during vehicle operation.

Today the average automobile has more computing power in it than Apollo13 did.

Here’s how the drivability system works in an average computer controlled car today. For arguments sake, let’s say that we have components A, B, C, D, and E. Component A is the computer, and B & C are sensors gathering information from various sources within the engine (water temperature, amount of oxygen in the exhaust, etc). The sensors send the information in the form of electrical impulses to the computer, which it reads and then makes the necessary adjustments based on the pre-set parameters from the factory (taking into consideration performance, emissions, shift points, etc) to insure that your car is running correctly. The adjustments are then translated into commands to the engine controls, which in this example are D & E. These components could be controls for electronic fuel injection or maybe ignition timing. All components work in concert with one another to make sure that your car delivers optimum performance and efficiency.

Problems start when a glitch is introduced into the system such as a broken wire or a bad component. Then, what I call the “Domino Effect,” takes flight. Since the computer only knows a certain parameter within which to work and can only read what is fed to it by the sensors, it will tax itself and any other component within the system to do what it has to do to achieve its goal of operating within factory-set parameters. It will over or under compensate the adjustments of other systems and components (over and over), sometimes to their demise. The only problem with this scenario is that, more often than not, other components within the system suffer as a result of the computer taxing everything else to achieve its objectives. This is why it’s so important to keep you car maintained according to factory specifications in an effort to achieve automotive synergy, harmony, peace, and balance within your car.

Now, everybody breathe deeply and repeat after me: Sparkplugssssssss, Wiressssssssssss, O-2 sensorssssssssssss, Air filtersssssssssss. You are achieving single-minded consciousness with Automotive Valhalla. Now allow yourself to drift off. Focus and picture the tires, wheels, fender-skirts ... as you draw closer to the ultimate ignition light of all consciousness.

’Til next time ... Keep Rollin’

 

 

 

"America's Car Show" with Tom Torbjornsen airs 7:30 p.m. Wednesday, 9 a.m. Thursday and 11 a.m. Saturday on WBBZ-TV.