State the
difference between ME engine and RT flex engine?
The two
major manufactures of two stroke cross head engines have both introduced a
camshaft less engine.
Sulzer
calls as RT flex engine and MAN B&W cal as intelligent engine.
Both
engine use electrical and engine driven axial piston pumps to pressurize servo
oil rails to 200bar which are then used for fuel injection and exhaust valve
operation. In addition MAN use the servo oil to drive the cylinder lubricator
units(alpha system).
Although
both work without a camshaft and use computers to control fuel injection,
exhaust valve operation and air starting, the method of fuel injection is
different.
…
Unlike
the sulzer RT flex engine the MAN ME engine does not operate the fuel injection
on a common rail system.
Instead a
solenoid operated proportioning valve (the FIVA valve - fuel injection valve
activation ) allows the pressurised servo oil under a hydraulic piston. This
then moves the fuel piston upwards, raising the fuel pressure and opening the
injection valves.
A
nitrogen filled accumulator maintains the hydraulic servo oil pressure during
the operation of the pump.
To be
able to time the fuel injection the control systems must know the crank angle
of the individual units. To do this two crank angle sensors are fitted at the
free end of the engine. These sensors are accurate to 0.1%. Cylinder pressures
and powers are continously monitored by using strain gauges built in to the
cylinder head and the computer automatically compensated for twist in the
crankshaft when relating crankshaft position to cylinder pressure, the systems
give complete flexibility over start and end of injection and take into account
fuel quality, dead time (the time between injection start command being given
and actual injection), and variable injection timing (VIT)
1 comments:
It was helpful. Thank you.
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