|What’s Driving Your Boat?|
2: Detroit Diesel; Volvo Penta; MAN
By Capt. Patrick Sciacca — January 2001
Detroit Diesel's DDEC (Detroit Diesel Electronic Control) engines illustrate the company's belief that with electronic controls there are fewer parts, and that means fewer things to go wrong.
Similar to the other systems, DDEC monitors data such as oil pressure and temperature, engine coolant temperature, fuel temperature and pressure, and crankcase pressure. All this information can be displayed on a helm-mounted electronic display. The system's engine governing capabilities also protect against engine overspeed. Many consider this safeguard one of the most important benefits of electronic controls.
In addition to engine protection, Detroit says DDEC provides for an accurate horsepower rating. According to the company, engines are usually guaranteed to be within five percent (plus or minus) of their branded horsepower. On a 1,200-hp engine, this represents a 120-hp range, which could conceivably have a major effect on performance. Thanks to DDEC, Detroit Diesel guarantees its Series 2000's horsepower rating to within plus or minus two percent. As a result the owner gets all the horsepower and performance he paid for.
For instance, in the event of a problem, a lamp on the instrument panel will display a number code consisting of two groups of flashes. For example, "flash-flash-flash---flash-flash" is code 3.2, which you can look up in the owner's manual to reveal the problem. The operator can erase the display by turning the ignition switch off and then on again; however, the error code will be stored in the EDC's memory for technicians to view later. Technicians can also get the information via their Volvo Penta electronic service tool or a PC in text form.
But Volvo Penta's EDC takes monitoring one step further. If the EDC detects that the engine is operating outside accepted values, it will reduce power to preserve the engine as well as keep coolant temperature, boost pressure, and oil pressure within acceptable limits. Recently, while we were testing a boat powered by a Volvo Penta EDC diesel, the system shut down one engine, after water had somehow worked its way to the ECU, and put the other engine in "safe home" mode, not allowing it to exceed 1000 rpm. "One-thousand rpm is a limp-home value for the potentiometer signal giving the reference for engine speed," explains Pelle Nestvall, electronics product manager for Volvo Penta, adding that "at 1000 rpm it is still okay to shift gear without destroying the reverse gear." Unlike Cummins, Volvo Penta does not recommend running a diesel without a governor function, as it contends that engine can stall or overspeed. "The EDC system will keep the engine running as long as possible," Nestvall adds.
Like the other monitoring systems, EDC stores engine performance history and extreme values for speed, temperature, and pressure. This information helps to construct an engine's "load profile," which forms a matrix that can be accessed and interpreted as with Cummins and Caterpillar systems. In the future Volvo Penta says EDC will also monitor marine gears and that it will continue to add functions on the drive line to make for an optimized installation. Nestvall says that Volvo Penta will eventually "integrate the whole power train into one system including throttle, shift, power trim, and more."
The MMDS monitors engine speed, oil pressure, charge-air and coolant temperature, and coolant level. If a problem occurs with the engine, an alarm display will come up at the helm-mounted screen. (Optional displays are available for areas such as your boat's flying bridge, and other alarms can be added to watchdog areas such as the bilge.) The LCD panel can also display your engine's current values as well as the normal values.
Like other systems, MAN's stores engine-performance data in the MMDS's diagnostic unit, which can be read by a technician's computer. Similar to Volvo Penta's governing system, MAN's system will reduce engine power by 25 percent if an engine problem is detected. MAN's "get home" unit, which is also similar to Volvo Penta's, allows you to control engine speed incrementally and operate the transmission.
So it appears that zeroes and ones--bits and bytes of data--are what's really driving your boat. Or more specifically, your boat's electronic diesels. The technology is here today and growing rapidly. In fact new functions are added as quickly as we learn about the existing ones. But don't worry, technology is nothing to be afraid of, unless you lose the horizontal and vertical on your display.Caterpillar (800) 321-7332. Fax: (309) 578-2559. www.cat-marine.com
Cummins (800) 343-7357. Fax: (843) 745-1549. www.cummins.com
Detroit Diesel (313) 592-5000. Fax: (313) 592-5137. www.detroitdiesel.com
MAN (800) MAN-2842. Fax: (954) 946-9098. www.man-mec.com
Volvo Penta (757) 436-2800. Fax: (757) 436-5150. www.penta.volvo.se
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This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.