Method of Identifying and Stopping an Electronically Controlled Diesel Engine in Runaway Mode 2013-01-2735
A diesel engine is said to be in run-away mode when it runs out of control using an external fuel source and the operator cannot shut down the engine using conventional methods. During runaway, the engine damage can range from minor to catastrophic and this can cause enormous damage to the environment due to no emission control under these circumstances. In addition, an organization can incur financial losses due to loss of entire engine / engine components.
In engine applications, such as power generation in an oil refinery, the oil mist can enter the intake stream of the engine and cause an engine runaway. In some of the OHW (Off Highway) and CV applications, the oil separator is connected to the intake system to have close-loop crankcase breathing system where in the engine oil may enter the combustion chamber through intake & the engine turns to run-away mode. In scenarios where the turbocharger piston rings fail due to high pressure difference, the oil used for lubrication of turbocharger' bearings enters the intake through compressor resulting in engine running out of control till the oil in the crankcase sump is completely consumed.
In literature, one of the methods to detect a runaway condition is to check if the engine speed reaches unsafe values. It is also possible to detect a runaway condition based on current acceleration time and compare the same with the safe thresholds. Both these methods are not fast enough for runaway detection as they need to wait for a threshold violation to determine a runaway mode. In this paper, a method is proposed to improve the response time of the runaway detection system in electronically controlled engine applications.
The intention of the proposed method is to ensure very fast detection of the runaway condition and shutting off the engine using electronic controlled actuators, there-by saving the engine & engine components.