Difference between RT flex and ME-C engines is discussed in this article, hope you will find it useful.
If you are a marine engineer or a ship enthusiast, you might have heard of two types of low-speed engines that are widely used in modern ships: RT flex and ME-C engines. These engines are both based on the principle of electronic control, which means they do not use a camshaft to operate the fuel injection and exhaust valves. Instead, they use computerized systems that can adjust the timing and duration of these processes according to the engine load and speed. This allows for more flexibility, efficiency and reliability of the engine performance.
Difference between RT flex and ME-C
But what are the main differences between RT flex and ME-C engines? How do they work and what are their advantages and disadvantages? In this blog post, we will try to answer these questions and compare these two types of engines.
RT flex engines
RT flex engines are developed by Wartsila, a Finnish company that specializes in marine and energy solutions. RT flex stands for “real-time flexible”, which reflects the ability of these engines to adapt to various operating conditions. RT flex engines use a common-rail system for fuel injection, which means that the fuel is pressurized in a rail that supplies all the injectors. The fuel pressure is controlled by a set of jerk pumps that are driven by a three-lobe cam geared to the crankshaft. The pumps have variable delivery, which is adjusted by an electrically driven fuel pump shaft linked to the engine computer. The fuel injection is then activated by solenoid valves that open and close according to the signals from the computer.
Interesting to know that, on bigger RT flex engines, not all injectors fire on slow steaming. Only one injector out of 3 in single unit of main engine is firing. This is done with help of ICU.
The exhaust valves of RT flex engines are also operated by solenoid valves that control the flow of servo oil from a pressurized rail. The servo oil acts on hydraulic cylinders that open and close the exhaust valves. The servo oil pressure is generated by engine-driven axial piston pumps.
RT flex engines have some advantages over conventional camshaft engines, such as:
– Reduced fuel consumption and emissions due to more precise control of fuel injection and exhaust valve timing
– Improved engine performance and reliability due to less mechanical wear and tear
– Enhanced operational flexibility due to smooth and immediate reversing action without reconnecting camshaft, easy and smooth starting of the engine, lower engine revolution along with good slow steaming capacity
– Simplified maintenance due to fewer moving parts and easier access to components
However, RT flex engines also have some disadvantages, such as:
– Higher initial cost due to more complex and expensive components
– Higher power consumption due to electrically driven pumps and valves
– Higher risk of failure due to dependency on electrical and electronic systems
– Higher sensitivity to fuel quality due to common-rail system
ME-C engines
ME-C engines are developed by MAN Energy Solutions, a German company that provides solutions for marine, power generation and industrial applications. ME-C stands for “mechanically electronically controlled”, which indicates that these engines use a combination of mechanical and electronic systems to control the fuel injection and exhaust valves. ME-C engines do not use a common-rail system for fuel injection, but rather individual pumps for each cylinder that are driven by an electronically controlled hydraulic actuator. The hydraulic actuator is connected to a hydraulic cylinder that moves a plunger inside the pump. The plunger creates a high-pressure pulse of fuel that is injected into the cylinder through a nozzle. The fuel injection is then regulated by an electronic unit injector (EUI) that controls the opening and closing of a needle valve inside the nozzle.
The exhaust valves of ME-C engines are also operated by individual hydraulic actuators that are connected to hydraulic cylinders that move push rods. The push rods act on rocker arms that open and close the exhaust valves. The hydraulic actuators are controlled by solenoid valves that receive signals from the engine computer.
ME-C engines have some advantages over conventional camshaft engines, such as:
– Reduced fuel consumption and emissions due to more precise control of fuel injection and exhaust valve timing
– Improved engine performance and reliability due to less mechanical wear and tear
– Enhanced operational flexibility due to smooth and immediate reversing action without reconnecting camshaft, easy and smooth starting of the engine, lower engine revolution along with good slow steaming capacity
– Reduced power consumption due to mechanically driven pumps
However, ME-C engines also have some disadvantages, such as:
– Higher initial cost due to more complex and expensive components
– Higher risk of failure due to dependency on electrical and electronic systems
– Higher sensitivity to fuel quality due to individual pumps
– Higher maintenance cost due to more components
Conclusion
RT flex and ME-C engines are both examples of electronic control engines that offer more flexibility, efficiency and reliability than conventional camshaft engines.
