The basic measuring element of system is
the gas pressure sensor PS-16 (uncooled type).
From it the necessary data is obtained for calculation of indicated cylinder power and definition of the basic characteristics of working process.
is the auxiliary sensor of the system. The vibroanalysis of the various units of the fuel equipment and cylinder moving parts of a diesel engine allows to determine parameters of fuel- and valves timing.
Distinctive feature of DEPAS systems is usage of special algorithm for definition of the piston TDC - PLS algorithm. The algorithm has been developed and applied for the first time in DEPAS systems in 1996. From now on PLS algorithm has passed long testing for different types of engines and has been improved on the basis of the analysis of a huge amount of a accumulated experimental data.
The operational experience accumulated by us in the field of diesel engines monitoring allows to approve the following: usage of PLS algorithm at practical diesel engines indicating is more preferable on the following reasons:
A: TDC determination error account
***Fitting of phase sensor and flywheel marker (for TDC determination) is performed on non-working engine. During engine running correct TDC position is shifting due to crankshaft twisting (proportional to engine load); torsional vibration; engine moving parts clearances and other factors which is impossible to calculate in static conditions***
- PLS algorithm automatically accounting influence of crankshaft twisting under load (see example from 10K45GF B&W engine);
- PLS algorithm automatically accounting influence of discrepancy between true position of TDC and flywheel mark, due to influence of the excessive clearances in the engine moving parts and other operational factors(also possible non-accurate flywheel marking of the engine maker);
- PLS algorithm automatically accounting influence of pressure waves passage speed through the indicator cock channel (from the combustion chamber to the pressure sensor diaphragm);
B: possibility to perform indicating without additional engine preparation
***During working with engine performance systems which are using flywheel sensor and mark one of the most time and job consuming operation is fitting and adjusting of a flywheel sensor and flywheel marker***
- there are no wasted time and cost for installation of synchronizing sensors on flywheel;
- application of PLS algorithm allows to make a diesel engine indicating without special preparation which is necessary at hardware data synchronization (with flywheel sensors).
Accuracy of PLS algorithm and its correctness for different types of engines have been proved experimentally by comparison of real and calculated TDC data.
Now system DEPAS 2.34sp is developed in portable variant.
DEPAS systems allow to supervise a technical condition of the fuel equipment and engines moving parts according to requirements of the Appendix VI of MARPOL 73/78.
Use of systems DEPAS is approved by the Russian River Register.
The DEPAS 2... software, including all used mathematical algorithms of real time data processing and hardware (exhaust gas pressure sensors
vibrosensor VS-20, and also additional fuel high pressure sensor
and a high pressure fuel valve V-200)
are developed in the DEPAS Laboratory.