Be a meter reader

| December 12, 2008

All engine makers provide one or more software packages for downloading driver performance information onto a PC. The same adapter also can send detailed information about a faulty engine to the PC, although a different software package is normally required.

How much time did your truck idle last month? What percentage of your most recent trip did you spend in cruise? What was your average speed?

You may not know the answers to these questions, but they’re all readily available through your engine’s electronic control module. Data such as cruise speeds, gear engagement times, total idle time and number of hard stops can help you save fuel and engine wear and tear – and improve safety.

Originally developed by Detroit Diesel as an integral part of the diesel injection system, ECMs quickly became standard equipment on all engines. Adding a vehicle speed sensor enabled ECMs to provide cruise control with no throttle linkage; additional sensors and programming helped track driver performance.

Whether you access ECM data via a dash display or a personal computer, you can use it in several ways to reduce costs. Apart from the mechanical diagnostic functions of the ECM, such as fault codes, there are operational uses that will pay immediate dividends:

LOWER CRUISE SPEEDS. Because wind resistance increases with each bump in miles per hour, reducing speed improves fuel economy. An ECM data report that shows trip times and speeds can show whether you or, if you’re running more than one truck, one of your drivers needs to slow down to save fuel.

Setting reasonable goals is important, says Bob Keene, Caterpillar customer value manager. “You can’t tell them to slow from 75 mph to 55 mph, but you could suggest that they simply drive at the speed limit.”

Using cruise control also saves fuel by keeping the vehicle from straying above the intended cruise speed. Looking at cruise engagement time on the ECM data may show that cruise isn’t used often enough to get the best fuel economy. Many engine ECMs even provide an incentive, such as more torque or a higher maximum speed, to encourage drivers to use cruise control. Cummins PowerSpec, for example, helps modify driver behavior by monitoring fuel economy and idle times against preprogrammed values. Drivers who exceed those values can get a higher road speed governor setting, a higher maximum cruise setting and a more rapid increase in available torque under appropriate conditions.

REDUCE IDLING. Even experienced owner-operators sometimes lose track of how much they idle. If you’re among them, seeing the number of hours idled – and fuel wasted – in black and white can be a shock. It might even convince you to buy an auxiliary power unit or in-cab heater. Reducing idling not only saves fuel; if you use oil analysis to determine when to change, it also can significantly extend your changes because the reduced unburnt fuel and soot will show up in the numbers. Research shows engines that idle less last a lot longer.

SHIFT PROPERLY. Cruising in the right gear, and even accelerating with progressive shifting (early shifts in the lower gears), can save fuel by making the engine more efficient. But many drivers run in too low a gear to avoid downshifting on the next hill or because diesels run smoother at higher rpm. “The driver knows the engine is revving a bit higher, but may not know how much of an impact this has on miles per gallon,” says Atul Patel, Detroit Diesel product planner for heavy-duty engines.

Seeing a graphic display of the time spent in each gear can help you correct improper shift points. Some programs even record how much time the driver spends in the sweet spot, the ideal cruise rpm for a particular engine.

STOP HARD STOPS. By telling you what kind of following distance a driver maintains, data on hard stops can save fuel and safety costs. For example, drivers who back out of the throttle when they see slower traffic ahead actually recover energy in the form of inertia and use it to push the truck down the road; a hard stop just throws the energy away. A three-second-plus following distance is also a safety must at higher cruise speeds. This cushion enables the driver to stop without causing a rear-end collision.

Given the wealth of information available, you owe it to yourself to see how you can use it. Tap into the systems and software that will help you maximize your truck’s performance.

How to get the data
There are two major ways to retrieve data from an ECM: the on- or in-dash readout and computers.

The dash unit provides immediate feedback through real-time digital readouts, enabling you to fine-tune driving performance and correct bad habits.

All engine makers have dash digital display units: Caterpillar Cat Messenger, Cummins RoadRelay 4, Detroit Diesel ProDriver, Mack Co-Pilot and Volvo Driver Display. Integral dashboard screens are standard on Mack and Volvo trucks equipped with proprietary engines. Volvo also provides summaries of driver performance in real time over its Volvo Link website.

Data also can be retrieved and graphed through a personal computer. Several engine makers also let you use a Palm or other hand-held computer to access the data. Using a PC or Palm to retrieve data is especially useful when tracking performance of more than one driver.

Getting the data requires an RP 1210-compliant adapter, which costs about $500, says Wayne Wissinger, Mack manager for product planning and strategy. “RP” refers to a Recommended Practice of the Technology and Maintenance Council. In this case, it represents standard electronic equipment designed to be compatible with all engine ECMs.

The information is spit out of the ECM according to electronic protocols, or languages, that are standard on all trucks, such as SAE J1587 and J1939. You access the data by connecting the adapter to the serial bus, a 6- or 9-prong connector under the left side of the dash. The adapter itself consists of cables and an electronic black box similar to the signal converter you might have between your TV and DVD player. It translates the electronic impulses from the ECM and sends them to your PC.

The other requirement is software, which lets your PC convert all the digital information into an easy-to-read format called a histogram. Much of the software is free or affordable ($500 or less); some can be downloaded from the Internet. Histograms can show months’ worth of measurements, such as the time spent in each speed range or gear – habits that make up regular driving style, not just what happened on one trip.

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