Next-Generation Power: MTU
Two radically new engines may set the standard in marine power for years to come.
By Richard Thiel — June 2004
You don’t often see a truly new marine diesel. First of all, most marine diesels are marinizations of industrial engines, and second, most new models are simply more powerful versions of existing models. Considering the astronomical cost of creating a diesel from scratch, the lack of innovation is hardly surprising, but the result is a lot of marine engines that were designed a decade or more ago to produce far less horsepower and never intended to meet today’s stringent emissions regulations.
So the fact that MTU has designed a totally new diesel series specifically for use in boats is remarkable, to say the least. The fact that these engines are aimed at the 40- to 70-foot market (not including trawlers) makes them an exciting harbinger of things to come.
The first of the new Series 2000 Common Rail (CR) engines should be available as you read this—a V-8 and V-10 rated at 1,200 hp and 1,500 hp, respectively. (All new Series 2000 CRs will produce 150 hp from each 2.23-liter cylinder.) While they will still be called Series 2000s, the new engines have absolutely nothing in common with the old ones, not even the logos on the valve covers. That’s partly because MTU engineers used finite element analysis and advanced metallurgy to create an engine that is durable yet significantly lighter. In fact, the 10V 2000 CR weighs 20 percent less than the equivalently rated 12V 2000. To put that in perspective, replacing a pair of 12V 2000s with 10V 2000 CRs could take nearly a ton out of your boat. In addition, while MTU hadn’t released specific dimensions at presstime, it did say that the 10V CR’s overall bulk is about two-thirds that of the 12V 2000. That means more room for ancillary gear, or perhaps a smaller engine space and more accommodations.
So the CR excels at what engineers call “power density,” the result of allowing them to design from scratch. Since much of that process focused on the fact that this would be a marine engine, other benefits accrue, like a cooler engine room. By placing the charge-air cooler between the cylinder banks, water-cooling the turbochargers, and using triple-wall fuel lines and exhaust manifolds, MTU engineers ensured that no part of the engine will exceed 428ºF, which lets the CR qualify under the new SOLAS safety-at-sea regulations. Beyond safety, a cooler engine room means more horsepower and less need for extensive ventilation equipment.
But the real breakthrough is represented by the CR designation, which stands for common rail. As the name implies, this fuel-delivery system, found in the latest diesel-powered cars, uses one fuel line from which all injectors are fed. Because fuel is under very high pressure—more than 26,000 psi—it is instantly available regardless of load or engine speed, and throttle response is virtually instantaneous. MTU’s common rail system is unique in that each injector has its own reservoir, further enhancing the availability of fuel.
Complementing common rail and further enhancing throttle response is sequential turbocharging. On the 8V and 10V there are two identical turbochargers of MTU’s own design and manufacture, designated ZR 125 and capable of 85,000 rpm. One operates constantly; the other comes on line as rpm increases. The first unit supplies the necessary volume of air at low speed to generate sufficient torque to put a boat on plane, while the secondary unit creates the horsepower necessary for superior top speed. Sequencing is controlled by a new microprocessor that, like the engine, is significantly smaller and lighter yet more powerful. Designated Advanced Diesel Engine Control, or ADEC, also controls the timing and metering of each electronic fuel injector and has an integrated system interface that uses a widely available flash card, making it easier to program the engine to a particular application. A standard Ethernet connection allows engine diagnosis via the Internet, using either land line or satphone. Large integral data storage provides a permanent service and performance record.
All these features will be included on subsequent CR models like the triple-turbocharger 12V and 16V, rated at 1,800 and 2,400 hp, respectively, and currently under development. All CRs will be rated at 2450 rpm and meet EPA Tier II/Euro 2 emissions standards, making them not only truly new but better in just about every way that matters to a boater.
MTU Phone: (313) 592-5261. www.mtu-online.com.
This article originally appeared in the May 2004 issue of Power & Motoryacht magazine.