Claims:1.1. A method (100) to identify a drifting injector in a fuel injection system (12), said fuel injection system (12) comprising multiple fuel injectors (16) one each for the multiple engine cylinders in an engine, said method comprising the following steps:
- monitoring (102) rail pressure gradient over distance travelled by said vehicle in which said fuel injection system is operating;
- comparing (104) said monitored rail pressure gradient with a threshold rail pressure gradient value;
- learning (106) engine speed variation from an engine speed sensor and correlating said engine speed variation to a specific engine cylinder through the known fuel injector firing pattern;
- applying (108) a fuel balance control correction to correct said engine speed variation and correcting engine speed to a threshold engine speed value by changing the energizing time for said fuel injectors being fired;
- mapping (110) the fuel injected quantity deviation for each of said fuel injector while applying said fuel balance control correction;
- measuring (112) in real time engine speed variation using an engine speed sensor and measuring fuel injected quantity deviation while applying the fuel balance control correction for each of said fuel injector;
- identifying (114) a drifting injector by comparing measured value of fuel injected quantity deviation and mapped value of fuel injected quantity deviation;
- confirming (116) said identified drifting injector as a drifting injector if injected quantity deviation count is greater than a threshold injected quantity deviation count;
- alerting (118) a user based on said confirmation.
2. A electronic control unit (10) in a fuel injection system (12), said electronic control unit (10) configured to:
- receive from said engine speed sensor the engine speed value;
- applying a fuel balance control correction based on said received engine speed value from said engine speed sensor and a known fuel injector firing pattern;
Characterized in that said electronic control unit (10) configured to:
- monitor (102) rail pressure gradient over distance travelled by said vehicle;
- compare (104) said monitored rail pressure gradient with a threshold rail pressure gradient value;
- learn (106) engine speed variation from an engine speed sensor and correlating said engine speed variation to a specific engine cylinder through the known fuel injector firing pattern;
- apply (108) a fuel balance control correction to correct said engine speed variation and correcting engine speed to a threshold engine speed value by changing the energizing time for said fuel injectors being fired as a part of the known firing pattern;
- map (110) the fuel injected quantity deviation for each of said fuel injector while applying said fuel balance control correction;
- measure (112) in real time engine speed variation using an engine speed sensor and measuring fuel injected quantity deviation while applying the fuel balance control correction for each of said fuel injector;
- identify (114) a drifting injector by comparing measured value of fuel injected quantity deviation and mapped value of fuel injected quantity deviation;
- confirm (116) said identified drifting injector as a drifting injector if injected quantity deviation count is greater than a threshold injected quantity deviation count;
- alert (118) a user based on said confirmation.
, Description:The electronic control unit (10) in a fuel injection system (12), said fuel injection system (12) comprising at least a common rail (14) and a fuel injector (16), said electronic control unit (10) configured to: receive from said common rail (14) a rail pressure signal from a pressure sensor in said common rail; control the injection timing of said fuel injector (16), by controlling the actuation of the injector. The electronic control unit is able to identify the specific drifting injector in a group of injectors in a fuel injection system 12 using the engine speed variation and the injected quantity deviation.