May 16, 2011
Two radically new engines may set the standard in marine power for years to come.
The number four. It's the quantity between three and five, the sum of two plus two, and a myriad of other mathematical combinations and functions. And did you also know there is only one animal on Earth that has four knees?
Four is also the number of new four-stroke engines in Mercury Marine's Verado Series. The 200-, 225-, 250-, and 275-hp powerhouses are the culmination of a five-year, $100-million program which will, according to Mercury Marine, “produce the most sophisticated marine propulsion system in history.”
When the mission to develop these engines began, it was given the code name Project X by its planners and engineers who wanted to offer a line of high-horsepower, four-stroke outboards with excellent acceleration, speed, and durability that would set a new standard in the industry. But they wanted something more, which is why Verados also have an integrated steering and control system.
To deal with performance, all Verados are supercharged using a system developed with IHI Turbo America. By forcing more air into the combustion chambers, it enables the engines to develop big-displacement horsepower out of a smaller-displacement block. For example, a 250-hp outboard would normally use a 3.0-liter block; the Verado's displaces just 2.6 liters. All four engines are also straight sixes with 24 valves; direct-acting double overhead cams; computer-controlled, sequential multiport electronic fuel injection; and 1.85:1 gear ratios.
For sound attenuation, Verados have an idle-exhaust relief and low-pass acoustic system, as well as a high-performance acoustic foam liner in the top of each engine's distinctive cowling. Couple that with a highly tuned intake resonator, and the result, says Mercury, is a super-quiet engine. It claims the system reduces intake noise by 14 dBA from midrange to WOT. Furthermore a closed-cell acoustic foam liner inside the “chaps” absorbs high-frequency sound from both the engine and drive train. Finally, Mercury's Advanced Midsection mounting system cradles the engine at its center of gravity to reduce vibration transmitted to the boat.
With such a complex engine, quality control is crucial. That's why as each Verado part comes off the assembly line, it is subjected to constant measurement and testing. To ensure optimum quality, the blocks, cylinder heads, and crankcases are cast by Mercury in its own foundry in Fond du Lac, Wisconsin.
Besides using the latest mechanical engineering, the Verado is also intelligent. Mercury's SmartCraft digital engine-management system monitors all vital systems and delivers that data right to the operator at the helm. Thanks to SmartCraft, each engine employs Mercury's Digital Throttle and Shift (DTS) system, first introduced with the OptiMax engines in 2002, which eliminates control cables. A programmable two-speed trim and tilt is also standard, as is electro-hydraulic power steering courtesy of a small hydraulic cylinder and pump mounted inside the vessel.
In the highly competitive four-stroke market, Mercury is betting its Verado line will not only run with the established outboards, but outrun them by taking technology to the next level. As soon as the first Verados come off the assembly line and are mounted on transoms, PMY will test them and report back the findings.
And by the way, the only animal on Earth with four knees is the elephant.
Mercury Marine Phone: (920) 929-5000. www.mercurymarine.com.
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.