Introduction to Engine Electronics

Electronic engines are now the standard in the trucking, bus, and RV industries, and electronics engines such as the Cat 3126, Cummins IS series, and Navistar T530E comprise virtually 100% of the over-the-road market. Mechanical engines are today limited to a few industrial and marine applications where their disadvantages aren't as severe.

To understand why electronic engines have been so successful, it helps to understand what is meant by "electronic engine". In a mechanical engine, all engine functions are controlled by a mechanical system - the crankshaft. Since the crankshaft is rigid metal, the engine cannot adjust to changing conditions except through the direct intervention of a mechanic. In an electronic engine, certain engine functions are controlled by a small computer located on the engine. Typically this computer, or ECM (Electronic Control Module), controls the fuel rate and injection timing. Often it does more, sometimes it controls less. But the key is that the computer can adjust the delivery of fuel according to circumstances - literally moment-by-moment. You can think of it as having a mechanic in the engine, constantly tuning it according to whether you're cruising, climbing, or idling.

With that kind of power over the engine, it shouldn't be surprising that electronic engines typically get 5-10% better fuel economy than their mechanical brothers. Emissions are also significantly lower - in some cases, so low that you don't need a catalytic converter. This should be reason enough for most of us to upgrade to the new technology.

But for many, the best benefit of electronics is the fact that the ECM, as smart as it is, can communicate with us, if we have the means to listen. In order to do its job, the ECM is connected to a number of sensors. It also keeps track of how much fuel it's metering out, and much of this information can be extracted from the ECM with the proper equipment. Typically, mechanics access this data with a service tool or laptop computer. And almost all engine manufacturers provide a dash display that shows the same types of data. The VMS™ products are this type of display.

However, the VMS™ products are very different from the other devices available on the market today because the VMS™ does much more than just listen to the ECM. It actually analyzes the information, makes its own logs for future reference, and reports data that the other monitors can't. For example, almost all monitors will provide a reading of the "Instantaneous MPG". It doesn't require any computation, since the engine ECM generally reports it every second or so. But unfortunately, the number is almost worthless. Invariably, when the engine is under load it understates the real MPG, and when engine is allowed to coast it gives a wildly high MPG value. It rarely says anything in between. What the driver needs is a Rolling MPG, an average taken over a short distance. This evens out the ridiculous highs and lows, and gives an accurate indication of how the engine is performing. This is what the VMS™ products provide.

The difference is that the VMS™ products augments the ECM with its own analytical capabilities. While the ECM is busy with its business of running the engine, the VMS™ is calculating and giving you real-time information that you never dreamed you could have.

And unlike other engine monitors, the VMS™ products are not limited to just the engine. In fact, each VMS™ can be used to monitor a wide variety of sensors and peripherals, such as generator output and road temperature. It can even be configured to handle two engines at once - perfect for marine applications. No other product offers this kind of power and flexibility.