What's Driving Your Boat?

What’s Driving Your Boat?
What’s Driving Your Boat?
Computers are running the show in the engine room, making your diesels more reliable and efficient.

By Capt. Patrick Sciacca — January 2001

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• Part 1: What’s Driving Your Boat?
• Part 2: What’s Driving Your Boat? continued

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What powers your boat? Your first instinct might be to say fuel, but that's only partly true. Today what really makes modern marine diesel engines go is information, relayed in real time from an array of sensors and transmitted to an onboard computer where it is translated, analyzed, processed, and displayed and may even prompt you to take action. This may sound like something from the Outer Limits, where you no longer control the horizontal or vertical, but actually this technology can make your boat run better and provide you added peace of mind.

Although sophisticated electronic engine controls have been standard equipment in automobile engines for more than a decade, they're relatively new in marine diesels. Five major marine engine builders currently offer some form of electronic diesel engine system for your boat.

Cummins' newest engine, the QSM11, is its first to offer an electronically controlled fuel system. A sophisticated computer monitors rpm, coolant temperature, oil pressure, intake manifold temperature, engine load, turbocharger boost pressure, oil temperature, fuel-use rate, ambient temperature and pressure, percent throttle, total fuel used, total engine hours, trip fuel used, trip hours, and selected fault codes.

This data is used for a number of purposes. By analyzing key data components, the computer can ensure the precise amount of fuel is injected for the load and ambient condition at any moment. Fault codes precisely identify the nature of any engine problem; they are displayed on a flush- mountable 4.3"x 4.3" screen and retained in memory for review by a technician after the incident. The computer even advises the urgency of the problem with messages such as "repair at dock," "shut down," or "repair at next maintenance." And although the system has the capacity to automatically reduce engine speed in the event of an engine malfunction (what Cummins calls derating the engine), Cummins has deactivated this feature because of what it considers an inherent safety issue.

"An automatic derate of the engine has a potential safety issue for the passengers aboard if the boat is in a position where it needs full power," argues Rachel Bridges, communications manager for Cummins. "Much better to lose an engine than endanger the safety of those onboard." Worthy of note, however, is the fact that Caterpillar, Volvo Penta, Detroit Diesel, and MAN all offer some type of engine-governing functionality in their systems.

Cummins' system also maintains a history of engine performance, information that can tell a technician how hard the engine has been run. Not only can this historical data be used to identify abuse (i.e., if the engine has been run at full power in excess of the number of hours allowed by the rating), but also the company says it has been helpful in improving engine design. "We have found out that the recreational engines have been treated a lot more harshly by the saltwater environment than we originally anticipated," says Bridges.

Caterpillar has two separate monitoring systems available, both offering the same basic features. The Marine Power Display (MPD) is designed for smaller engines, while the Cat Engine Vision (EVD) system is geared towards bigger diesels. The MPD allows the operator to view rpm, coolant temperature, fuel rate, oil pressure, fuel pressure, fuel temperature, battery voltage, transmission pressure, and more, similar to the Cummins' system. It receives data through an SAE J1939 or J1587 ATA data link, a twisted wire pair or cable that transmits the engine data from the ECM to the displays. Data can be displayed in gauge, digital, and bar formats on a 320 x 240 pixel monochrome LCD screen measuring 5.82" H x 9" W x 1.88" thick. Optional software allows up to three users to personalize their screen. The MPD system is compatible with Windows 95 and 98 and NT 4.0 or newer.

Unlike MPD, EVD sports a color screen, can monitor up to three engines, and offers maintenance and histogram information like the Cummins system. Greg Hasler, project engineer for Caterpillar, says that one of the most useful discoveries the company has gleaned by analyzing this historical data is that many of its diesels spend a lot more time running at cruise speed than engineers originally anticipated. Hasler adds that Caterpillar plans upgrades for both systems, while researching new monitoring and maintenance technology.

Caterpillar says that unlike Volvo Penta and MAN, its monitoring systems do not currently offer engine control function, with one exception: The EVD on 3500 Series diesels enables you to start and stop the engine with the system.

Next page
> What's Driving Your Boat? continued > Page 1, 2

This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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