MAN B&W develops electric engines

Engine manufacturer MAN B&W is moving ahead with its plans to develop "intelligent" ship engines with electronic devices controlling the fuel injection rates, exhaust valve timing and other sparks, flows and pressures, all running off a computer.

This electronic control makes sure that the engine is operated in the most optimum possible way, taking into account the speed of the ship, the type of fuel, the emission allowances. This leads to minimum fuel consumption and reduced engine wear, leading to reduced repair, maintenance and lube oil consumption, and longer times between engine overhauls. 

It also means that the engine can accelerate more easily (go from low load to high load). There can be improved engine diagnostics systems; because everything is electronically sensed and controlled, it is easier to find out if something is going wrong. 

There are also less mechanical parts to go wrong. There is no chain drive, chain wheel frame, chain box, camshaft, roller guides for fuel pumps, fuel injection pumps, exhaust valve actuators, starting air distributor, regulating shaft, mechanical cylinder lubricator. 

They are replaced by a hydraulic power supply, electronically profiled injection, fuel oil pressure boosters, a crankshaft position sensing system and electronically controlled lubricator. 
Electrical start up pumps maintain hydraulic oil pressure at start up, then the engine driven pump takes over.

The engine is being continuously monitored to make sure that there is uniform load distribution across the cylinders, preventing heat overload. 

The company notes that whilst computer equipment is standard practise on most ships for cargo management, navigation and communication, electronics are generally kept away from ships engines; most ship engines still use mechanical systems.

"We believe that this situation will change over the next few years, as has happened in the automobile industry over the past 10-15 years," says Peter Sunn Pedersen, MAN B&W executive vice president. 

MAN B&W first presented a completely finished electronic engine in February 2003, which it considered "The greatest technical step forward in the technology of large marine diesel engines since [the company] introduced turbocharging of such large two-stroke engines in
1952."

The engine was tested on a 37,500 dwt chemical carrier Bow Cecil, owned by Odfjell, with the test running for 2.5 years with over 10,000 hours of operation. Odfjell was so pleased with the trial that it commissioned the very first production line electronic engine which MAN B&W produced. 

The company has already been working on the project for 12 years, with some 200-man years, or around 17 full time staff.  

The biggest benefit of the electronic engine is the improved control of fuel injection pressure control. This has typically been managed by mechanical cams (rotating switches). But the electronic control has much more flexibility. 

For example, with an electronic engine, the injection pressure can be increased when the vessel is going slowly or is running empty (low engine load), and reduced if the vessel is going fast or laden  (high engine load).

The electronic control of the lube oil feed can make sure that only the minimum amount of lube oil is supplied to the engine. This has proven to lead to savings in lube oil of 0.3g / bhph (British horsepower hours) the engine uses.

To reduce the risk of engine failure, it is designed so that no single failure can make the engine inoperative. 

There are several different computers. All essential computers have a hot (ready to go) standby. The computers are referred to as engine interface control unit, engine control unit, cylinder control units, and auxiliary control units. But they can all replace each other.

The engine is also designed so that it is easy for shipyards to stop fitting mechanical engines and start fitting electronic engines. The height, engine seating, engine outline are the same. Engine weight is slightly reduced. The engine pipe connection is similar and the lubricating oil system slightly modified.




pdp@manbw.dk
Peter Dan Petersen
Senior Manager
PR & Documentation