Corrupting a governor

Today’s speed governors are far from being tamperproof. Making that a reality, though, would involve substantial costs.

Of the thousands of comments filed on the two petitions to govern truck speeds at 68 mph, one of the least debated topics is whether governors can be truly tamperproof. What appears to be a simple, password-protected system is, upon closer examination, not so simple or well-protected.

This already is a concern for many fleets, according to preliminary results from a study done this spring by the American Transportation Research Institute. In the study, 30 percent of fleet executives said they consider driver tampering with speed settings to be an issue. Moreover, 78 percent would fire or otherwise punish a driver for tinkering with the governor.
It’s a hot issue for manufacturers, too. “Our principal concern with the proposal is the suggestion that speed limiters be ‘tamperproof,'” wrote Robert Clarke, president of the Truck Manufacturers Association.

For example: To properly calibrate the governor with the speedometer, the electronic control module may require reprogramming after a change in tire size or rear axle ratio.

Another TMA concern is the cost of retrofitting all vehicles back to the 1990 model year, a tall order requested in the petition by Road Safe America and 10 fleets. (The American Trucking Associations’ petition calls for the mandate only on new trucks.)

Vehicles built in the early- to mid-1990s may require mechanical governors that TMA says would cost $1,000 to $1,500 per truck, depending on brand. “These devices are not tamperproof and can easily be reset,” Clarke wrote.

What TMA calls the simplest approach – securing the password more effectively – still would allow mechanics to make changes. Fleet managers could decide they wanted drivers to run faster than 68 mph, and order it done across the board, or a driver with the right influence in the shop could get his way.

A more secure approach would be to “modify ECM software to provide a fixed road speed limit that is not readily accessible to vehicle owners — i.e., make this a factory password-protected feature,” TMA says. In that case, anyone who wanted the governor adjusted would have to go through the manufacturer.

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The most ironclad approach, TMA says, would be “Creating new engine control system hardware and software to ‘hard-wire’ existing vehicles.” Under such a system that’s separate from the ECM, it’s not clear how – or if – it could be adjusted to accommodate a change in wheel size or axle ratio.

Based on those levels of changes, TMA estimates the per-vehicle cost of retrofitting the 1 million trucks built since 1990 at as little as $100 or as much as $2,000. This means a price tag for U.S. fleets of anywhere from $100 million to $2 billion, plus the expense of software and hardware development borne by the vehicle manufacturers.

Even if regulators reject the retrofit proposal and focus on new trucks, the “tamperproof” challenge remains.

One way to access the ECM is with a plug-in tool specially programmed to communicate with the device. An alternative is with a computer equipped with special software. In some cases, the ECM can be instructed to disable the password requirement, ideal for a one-truck owner-operator who’s not concerned about ECM access or who would rather not bother with a password.

“Typically, the truck owner controls the password, and a designated technician knows it and is in charge of the reprogramming,” Mack’s Wayne Wissinger says. “If unauthorized reprogramming of the road speed limit is made, typically the fleet or owner-operator then changes the password.” This method has been successfully used for years, he says.

Some engine makers allow the owner to download software and use a computer to make changes via a cable connection to the ECM.

Caterpillar requires the Cat Electronic Technician or Caterpillar Pocket Technician computerized devices with a customer-programmable password to change the speed setting.

Cummins uses the Insite computerized device at engine distributors and dealers. Owners can use Cummins’ PowerSpec, a downloadable program.

Owners of Volvo and Mack engines need diagnostic and programming software, VCADS, to change the password, say Bo Hammerlid, Volvo marketing product manager, and Wissinger.

“The real problem is drivers trying to defeat the on-vehicle governor by various means, such as disabling the mph sensor, backing it out of the transmission, shorting it,” or other tricks, Wissinger says.

Truckers fed up with a governed speed – especially owner-operators in control of their ECM’s password – sometimes can get their speed setting adjusted.

While any password can be broken, Caterpillar makes doing so more difficult, says Mike Powers, Cat product development manager. The ECM will control the road speed by calculating the equivalent engine rpm and limiting revs.

“If the customer-level password is not secure enough, we have the capability to use the factory password system to protect the vehicle speed limit,” Powers says.

Almost all Caterpillar settings fall between 62 mph and 72 mph, with the majority between 65 and 68, Powers says. The range of settings for competitors’ engines is similar, spokesmen say.

In the American Transportation Research Institute survey, settings used by the carrier respondents range from 60 mph to 85 mph. Speeds over 70 mph were mainly chosen by smaller carriers.

Some carriers use higher or lower settings to encourage or discipline drivers regarding company policies. Carriers also vary settings depending on the type of equipment, the type of road the truck runs on, or whether the driver is an employee or an owner-operator.

A system without any cross-check of governed rpm and vehicle speed, however, also could be defeated by reprogramming the ECM in another area, as TMA points out. For example, a truck with 3.40:1 drive axles might have the governor set at 65 mph. Change the settings to indicate the truck now has a 3.70:1 axle, and the governor would be reset automatically, to 70.7 mph.

Just as inventors have come up with ways to foil police radar, some sort of electronic gadget conceivably could enable a driver to buffalo a speed sensor. Indeed, such a system reportedly has been sold over the Internet.

The electronic control module first was installed by Detroit Diesel on a Series 92 in the mid-1980s. It replaced the mechanical governor and controlled the injectors to shape the torque and power curves. This allowed the fuel system to more quickly adapt to changes in engine load and speed, and also permitted the injection timing to vary with rpm and load. This minimized emissions and optimized performance. Ultimately, all the other engine manufacturers followed suit.

In the 1970s, trucks were geared so the engine would reach its governed 2,100 rpm at cruise speed. A fleet maintenance manager named Robert Deal at Signal Delivery hit upon the idea of gearing for fuel economy and driving at the same cruise speed, calling the concept “gear fast, run slow.” Some of the fleet’s trucks were geared so the engine ran at 1,600-1,700 rpm, which achieved spectacular improvements in fuel economy.

The ECM took over the function of cutting the fuel as the engine exceeded governed speeds of 2,100 or 1,800 rpm, but this still allowed the truck to run much too fast if the driver had a heavy foot.

Engineers then introduced a new system to measure vehicle speed. The ECM was ultimately enabled to operate the speedometer electronically, eliminating the old wear-prone drive cable.

All that was needed to control vehicle speed was to add programming. Today’s ECMs are programmed to cut the fuel at either governed rpm or road speed, whichever comes first.

Among fleets that rely on both company drivers and owner-operators, 24 percent require both groups to set their governors at the same speed, according to preliminary results from an American Transportation Research Institute survey. This is done partly to minimize the perennial friction between the two camps.

The 100 owner-operators leased to Central Refrigerated Services of Salt Lake City are expected to comply with the companywide 65 mph speed limit, says Ian DeGrey, lease administrator. Since about 95 of them lease their trucks from the fleet, the company can program the governor before the driver takes delivery of the truck. “Drivers are terminated if tampering with the setting,” DeGrey says.

The 5 percent of owner-operators who bring their own trucks to the fleet operate free of ECM control, but the 65 mph speed limit is in their lease agreements. “We can keep an eye on them via the Qualcomm units installed in every truck,” DeGrey says.

Owner-operators don’t complain much, DeGrey says. “That has a lot to do with the benefits that come along with running at lower speeds,” he says. “Running at 75 versus 65 will cost you 3,000 gallons of fuel in a year driving 150,000 miles” – not to mention added maintenance costs, and added downtime from all those fuel stops.