Armed with JAQUET MDS 4000’s information window into the engine, the operator is now in a position to decide when maintenance is required, rather than relying upon predetermined schedules. One railway operator established that more than 50% of injectors changed during preventive maintenance schedules were still in good and usable condition. MDS 4000 has now been installed to enable event based maintenance while ensuring optimum fuel consumption by not running engines too long with early cylinder defects.The theory that the variable component of an engine’s torque is directly proportional to the steady state value has been known for many years. By developing a software model of a diesel engine’s behavior as it rotates, Switzerland based JAQUET TECHNOLOGY GROUP is now applying this theory to the online monitoring and diagnostics of a range of engines from 4 to 18 and more cylinders.

Engine components which exhibit linear motion along with the compression and combustion cycles influence the behavior of the crankshaft resulting in speed variations as the engine rotates. These speed variations representing around 0.5% of running speed are captured and analyzed by the new MDS 4000 in relation to the model of a given engine type. In this way, real time torque and total power output values are available for display or other control functions such as automatic gearbox control in a truck, together with data on the contribution made by each cylinder.

The contribution of work done by each cylinder would not be evident from measuring total power output on a dynamometer since the engine’s governor or ECU will compensate for under-performance of one cylinder by injecting more fuel to achieve the requested speed.

MDS 4000 in contrast follows the progress of rotation to determine whether cylinder performance is uniform. Under-performance may be displayed in chart form or applied to an alarm relay with a definable trigger level. The system is also equipped with a CAN-bus interface through which the data can be communicated with the ECU.

Cylinder under-performance might for example be symptomatic of misfiring, injector problems or piston ring wear causing low compression. Catastrophic failure seldom occurs without warning signals and MDS 4000 can be configured to provide trend data in addition to alarm signals.