Marine Diesel Engines - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 162

Table 11.5 Operation monitoring of marine diesel engines

Operation
monitoring

Operation measures

Cylinder pressure Cylinder pressure is used to control the efficiency of the cylinders.

Changing cylinder pressure can be analyzed with sensors. The sources
of efficiency losses are usually leaks in pistons, insulation rings, valves,
etc. Regulating the injection pressure maintains the life time of these
elements and saves a high quality of the injection and combustion
process [ 24 ]

Exhaust gas
temperature

Currently, exhaust gas temperatures can be measured with micro sensors,
similarly to cylinder pressures. In the normal case, if the injection
pumps are adjusted to the same capacity and to the same performance,
the same or very similar exhaust gas temperatures exist in all cylinders
Sources of differences must be discovered [ 25 ]

Combustion process For short on-board analyzes, unburned substances can be measured with a

solid electro chemical cell, CO 2 with a micro FTIR analyzer and NO
with a modified Lambda sensor. However, electro chemical cells
cannot differentiate between HC and CO, on-board FTIR analyzers are
very sensitive against particles and Lambda sensors have a cross
sensitivity to NH 3. Ammonia can be produced in the exhaust gas after
treatment system if SCR technology is applied [ 26 ]

Surge of compressor Under special operating conditions the turbocharger 0 s compressor goes

into surge or stalled operation. This process produces a loud noise
because it works in an instable operation range which causes an intense
back and forth flow on the compressor rotor. The surge can be avoided
with improved operating conditions., e.g., with increased number of
revolutions of the engine, with increased temperatures in the air
entering, with cleaning the compressor, the turbine and the naturally
aspirating air filter, and with blowing off the intake air channel and the
exhaust gas channel [ 27 ].

Injection system Piezo-electrically actuated injection systems present the stand-of-the-art.

Most reasons for deviations are defects in the injection valves, in the
injection pumps and in the connected pipes. In most cases, the injection
valves are carbonized, the pre-heating temperature of the fuel is too
low or the fuel is contaminated by water. Measurement can be done
with nozzle needle and valve lift sensors, pressure, temperature and
actuator force analysis, dynamic pump drive, torque and power, and
fuel consumption consideration [ 28 ]

Inlet and outlet
valves

Inlet and outlet valves regulate the gas recirculation. They are constructed
with overlapping. Most disturbances are related to leaky and dirty inlet
and outlet valves [ 29 , 30 ]

Piston ring Statistics shows that the main reasons for repairs and changes of piston

rings are leaks [ 31 ].

Turbocharger 0 s
compressor

The nozzle ring is one of the weakest points of the turbocharger's
compressor. If the compressor's nozzle ring is worn, the cooler of the
charge-air does not operate efficiently [ 32 ]

loaded parts such as propellers. However, the costs of ceramics parts are still high.
Moreover, they cannot fulfill a lot of mechanical and chemical requirements in the
construction yet [ 35 ].