ECD SYSTEM (w/ EGR Cooler Bypass Valve) SYSTEM DESCRIPTION


  1. ENGINE CONTROL SYSTEM

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    Text in Illustration
    *1 ECM *21 Camshaft Position Sensor
    *2 Atmospheric Pressure Sensor *22 Crankshaft Position Sensor
    *3 Supply Pump Assembly *23 Mass Air Flow Meter (Intake Air Temperature Sensor)
    *4 Suction Control Valve *24 Turbocharge Sub-assembly
    *5 Fuel Temperature Sensor *25 Turbo Motor Driver
    *6 Fuel Tank Sub-assembly *26 Actuator (DC Motor, Nozzle Vane Position Sensor)
    *7 Common Rail Assembly *27 E-VRV for EGR
    *8 Fuel Pressure Sensor *28 VSV for EGR Cut
    *9 Pressure Discharge Valve *29 VSV for EGR Cooler Bypass Valve
    *10 Injector driver (EDU) *30 VSV for Swirl Control Valve
    *11 EDU Relay *31 Vacuum Pump Assembly
    *12 Fuel Injector Assembly *32 EGR Cooler Assembly
    *13 Diesel Throttle Body Assembly *33 Accelerator Pedal Position Sensor
    *14 Manifold Absolute Pressure Sensor *34 Generator Assembly
    *15 EGR Valve (EGR Valve Position Sensor) *35 Ignition Switch Signal
    *16 GLOW Relay *36 Starter Signal
    *17 Glow Plug Assembly *37 Vehicle Speed Signal
    *18 Engine Coolant Temperature Sensor *38 DLC3
    *19 Diesel Turbo Inlet Air Temperature Sensor *39 Battery Voltage
    *20 Intercooler Assembly *40 Clutch Switch Signal

  2. COMMON RAIL SYSTEM DESCRIPTION


      COMMON RAIL SYSTEM:

    • The common rail system uses high-pressure fuel to improve fuel economy and to provide robust engine power, while suppressing engine vibration and noise.

      This system stores fuel, which has been pressurized and supplied by the supply pump assembly, in the common rail assembly. By storing fuel at high-pressure, the common rail system can provide fuel at stable fuel injection pressures, regardless of engine speed or engine load.

      The ECM regulates the fuel injection timing and volume by using the EDU to provide an electric current to the solenoid valve in the fuel injector assembly. The ECM also monitors the internal fuel pressure of the common rail assembly using the fuel pressure sensor. The ECM causes the supply pump assembly to supply the fuel necessary to obtain the target fuel pressure.

      In addition, this system has a 2-Way Valve (TWV) inside the fuel injector assembly to open and close the fuel passage. As a result, both fuel injection timing and fuel injection volume can be precisely regulated by the ECM.

      The common rail system provides two split fuel injections. In order to soften combustion shock, this system performs "pilot-injection" as the subsidiary fuel injection prior to the main fuel injection. This helps to reduce engine vibration and noise.

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      COMMON RAIL SYSTEM COMPONENTS:
      Component Description
      Common rail assembly Stores high-pressure fuel produced by supply pump assembly
      Supply pump assembly Operated by crankshaft. Supplies high-pressure fuel to common rail assembly.
      Fuel injector assembly Injects fuel to combustion chamber based on signals from ECM
      Fuel pressure sensor Monitors internal fuel pressure of common rail assembly and sends signals to ECM
      Pressure discharge valve Based on signals from the ECM, opens valve when sudden deceleration is occurred, or when the ignition switch is off to prevent the fuel pressure from becoming too high.
      Suction control valve Based on signals from ECM, adjusts fuel volume supplied to common rail assembly and regulates internal fuel pressure

      DIAGNOSTIC TROUBLE CODE (DTC) TABLE FOR COMMON RAIL SYSTEM:

    • Tech Tips

      This table indicates typical DTC combinations for each malfunction occurrence.

      Trouble Area Malfunction DTC No.
      Fuel injector assembly Open or short in injector circuit P0200, P1238, P0093*
      Stuck open P0093, P1238
      Stuck closed P1238
      Fuel pressure sensor Open or short in fuel pressure sensor circuit or pressure sensor output fixed P0087, P0190, P0191, P0192, P0193
      Pressure discharge valve Open or short in pressure discharge valve circuit P1271, P1272, P0088*, P0093*, P1229*
      Stuck open P0093
      Stuck closed P1272, P0088*
      Suction control valve Open or short in suction control valve circuit P0627, P1229, P0088*
      Stuck open P1229, P0088*
      Stuck closed -
      EDU Faulty EDU P0093*, P0200*, P1238*, P1271*, P1272*
      Common rail system (Fuel system) Fuel leaks in high-pressure areas P0093

      Tech Tips

      *: There may be no DTC output depending on the condition of the malfunction.

    DIAGNOSTIC TROUBLE CODE DESCRIPTION FOR COMMON RAIL SYSTEM:
    DTC No. Description
    P0087 Fuel pressure sensor output does not change
    P0088

    Internal fuel pressure too high (200 MPa [2,039 kgf/cm2, 29,007 psi] or more)
    P0093 Fuel leaks in high-pressure areas
    P0190 Open or short in fuel pressure sensor circuit (Low or high output)
    P0191 Fuel pressure sensor out of range (Low output)
    P0192 Open or short in fuel pressure sensor circuit (High output)
    P0193 Open or short in fuel pressure sensor circuit (Sensor 1 and/or 2 relation)
    P0200 Open or short in EDU or injector circuit
    P0627 Open or short in suction control valve circuit
    P1229 Fuel over-feed
    P1238 Injection malfunction, exclude open or short in injector circuit
    P1271 Open or short in pressure discharge valve circuit
    P1272 Closed malfunction of the pressure discharge valve

  3. INJECTION CONTROL SYSTEM DESCRIPTION

    The ECM controls the fuel injection system by using the fuel injector assembly and supply pump assembly. The ECM regulates the fuel injection volume and fuel injection timing by controlling both the duration and timing of energizing to the solenoid valve in the fuel injector assembly. The ECM regulates injection pressure by controlling the suction control valve located in the supply pump assembly.

    The feed pump is used to pump fuel from the fuel tank sub-assembly to the supply pump assembly.

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  4. SUPPLY PUMP OPERATION SYSTEM DESCRIPTION

    The rotation of the eccentric cam causes the ring cam to push plunger A upward as illustrated below. The spring force pulls plunger B (located opposite plunger A) upward. As a result, plunger B draws the fuel in, and plunger A pumps fuel out at the same time.

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  5. SUCTION CONTROL VALVE OPERATION SYSTEM DESCRIPTION

    Tech Tips

    The ECM controls the suction control valve operation to regulate the fuel volume that is pumped by the supply pump assembly to the common rail assembly. This control is performed to adjust the internal fuel pressure of the common rail assembly to the targeted injection pressure.


    1. Small opening of the suction control valve:


      1. When the opening of the suction control valve is small, the fuel suction path is kept narrow. Therefore the transferable fuel volume is reduced.

      2. The suction volume becomes small due to the narrow path despite the plunger stroke being full. The difference between the geometrical volume and suction volume creates a vacuum.

      3. Pumping will start when the fuel pressure becomes higher than the common rail pressure.

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    2. Large opening of the suction control valve:


      1. When the opening of the suction control valve is large, the fuel suction path is kept wide. Therefore the transferable fuel volume is increased.

      2. If the plunger stroke is full, the suction volume becomes large because of the wide path.

      3. Pumping will start when the fuel pressure becomes higher than the common rail pressure.

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