FUEL SYSTEM DETAILS


  1. SYSTEM CONTROL


    1. Common-rail System


      1. In this system, the highly pressurized fuel supplied by the supply pump is stored in the common-rail, and the ECM sends signals to the injectors via the injector driver in order to control the injection timing and injection volume.

        A01EZONE01
        Text in Illustration (Model Compliant with EURO 5 Emission Regulations:)
        *A Models for Europe *B Except Models for Europe
        *1 Fuel Pressure Sensor *2 Common-rail Assembly
        *3 Pressure Discharge Valve *4 Supply Pump Assembly
        *5 Fuel Temperature Sensor *6 Suction Control Valve (SCV)
        *7 Injector Assembly *8 Turbocharger Sub-assembly
        *9 Exhaust Fuel Addition Injector Assembly *10 Fuel Filter Assembly
        *11 Fuel Cooler *12 Fuel Tank
        *13 Injector Driver *14 ECM
        *15 Crank Position Sensor (NE Signal) *16 Camshaft Position Sensor (G Signal)
        *a Fuel (Suction) *b Fuel (Return)
        *c Fuel (High Pressure) *d Fuel (to Exhaust Fuel Addition Injector Assembly)
        A01EZ89E03
        Text in Illustration (Except Model Compliant with EURO 5 Emission Regulations:)
        *A Models for Europe *B Except Models for Europe
        *C Models Compliant with EURO 4 Emission Regulations and Models Compliant with EURO 2 Emission Regulations with Variable Nozzle Vane Type Turbocharger - -
        *1 Fuel Pressure Sensor *2 Common-rail Assembly
        *3 Pressure Discharge Valve *4 Supply Pump Assembly
        *5 Fuel Temperature Sensor *6 Suction Control Valve (SCV)
        *7 Injector Assembly *8 Fuel Filter Assembly
        *9 Fuel Cooler *10 Fuel Tank
        *11 Injector Driver *12 ECM
        *13 Crank Position Sensor (NE Signal) *14 Camshaft Position Sensor (G Signal)
        *a Fuel (Suction) *b Fuel (Return)
        *c Fuel (High Pressure) - -

  2. CONSTRUCTION


    1. Supply Pump Assembly


      1. An HP3 type supply pump is used.

        A01EZ5CE01
        Text in Illustration
        *A Models Compliant with EURO 5 Emission Regulations *B Except Models Compliant with EURO 5 Emission Regulations
        Supply Pump Specifications
        Type HP3
        Length C 190.2 mm (7.49 in.)
        D 129.0 mm (85.08 in.)
        SCV 1
        Plunger φ 8.5 mm x 2
        Weight 3800 g (8.38 lb)

        Tech Tips


        • The ECM learns and memorizes the pump discharge volume variances associated with the individual differences in the supply pumps. Therefore, make sure to perform the operation described below after replacing the supply pump. For details, refer to the corresponding Repair Manual for this model.

        • Connect an intelligent tester II to the DLC3 connector and use the tester to reset the learned value. Alternatively, connect the SST (09843-18040) between the TC and CG terminals of the DLC3 connector, and leave the ignition switch ON for approximately 3 minutes to reset the learned value.

        • After resetting, start the engine, allow it to idle* for approximately 1 minute, and turn the ignition switch off to enable the engine to memorize the learned value.


        • *: The engine coolant temperature should be 60°C (140°F) or more, and the fuel temperature should be 20°C (68°F) or more.

      2. The supply pump consists of an eccentric camshaft, a ring cam, 2 plungers, 4 check valves, a Suction Control Valve (SCV), a fuel temperature sensor, and a feed pump.

      3. The 2 plungers are placed opposite each other outside of the ring cam.

        A01EZM8E01
        Text in Illustration
        *A Models Compliant with EURO 5 Emission Regulations - -
        *1 Check Valve (for Suction) *2 Plunger
        *3 Eccentric Camshaft *4 Ring Cam
        *5 Check Valve (for Discharge) *6 Feed Pump
        *7 Fuel Temperature Sensor *8 SCV
        *9 Eccentric Cam Portion - -
        *a From Fuel Tank (for Suction) *b To Fuel Tank (for Return)
        *c To Common-rail *d To Exhaust Fuel Addition Injector Assembly

    2. Common-rail Assembly


      1. The function of the common-rail is to store the fuel that has been pressurized by the supply pump.

      2. The common-rail is provided with a fuel pressure sensor and pressure discharge valve.

      3. The fuel pressure sensor detects the fuel pressure in the common-rail.

      4. The pressure discharge valve regulates the fuel pressure. In the pressure discharge valve, the plunger opens and closes in accordance with the actuation signals from the injector driver. Thus, it regulates pressure by releasing excess pressure from the common-rail. In addition, it has a pressure reduction function in case of emergency.

      5. Internally, the common-rail contains a main hole and 5 branch holes that intersect the main hole. Each branch hole functions as an orifice that dampens the fluctuation of the fuel pressure.

        A01EZP2E01
        Text in Illustration
        *A Models Compliant with EURO 5 Emission Regulations *B Except Models Compliant with EURO 5 Emission Regulations
        *1 Common-rail Assembly *2 Fuel Pressure Sensor
        *3 Pressure Discharge Valve *4 Branch Hole
        *5 Main Hole - -
        A01EZFI From Supply Pump A01EZJZ To Injector Assembly
        A01EZPY To Fuel Tank (Excess Pressure) - -

        Tech Tips


        • The fuel pressure sensor has its sealing portion plastic-deformed in order to keep sealing performance, so do not reuse it after disassembling.

        • If parts that affect the alignment have been changed, make sure to replace the pipe with a new one as well. The parts that require the replacement of a pipe are listed below:


          • Injection pipe: injector, common-rail, and cylinder head

          • Fuel inlet pipe: supply pump, common-rail, cylinder block, cylinder head, cylinder head gasket and timing gear case

        • For details, refer to the corresponding Repair Manual for this model.

    3. Injector Assembly


      1. Except on the models compliant with EURO 5 emission regulations, each injector assembly consists of a nozzle needle, a piston, and a solenoid valve.

      2. On the models compliant with EURO 5 emission regulations, each injector assembly consists of a nozzle needle, 2 pistons, a three-way valve and a piezo actuator.

      3. An injector compensation value and a Quick Response (QR) code containing encoded characteristics of the injector are printed on each injector.

      4. The injector compensation value and QR code contain various pieces of information regarding the injector, such as model code and injection volume correction.

        A01EZOPE01
        Text in Illustration
        *A Models Compliant with EURO 5 Emission Regulations *B Except Models Compliant with EURO 5 Emission Regulations
        *1 Injector Assembly *2 Piezo Actuator
        *3 No. 1 Piston *4 No. 2 Piston
        *5 Three-way Valve *6 Nozzle Needle
        *7 QR Code *8 Injector Compensation Value
        *9 Solenoid Valve *10 Piston

        Tech Tips


        • If the ECM is replaced, use the intelligent tester II and input the injector compensation values of all 4 injectors. If the injector is replaced, input the injector compensation value of the replaced injector. Then, the proper compensation will be made so that the injection volume precision prior to the replacement will remain unchanged. For details, refer to the corresponding Repair Manual for this model.

        • The QR code, which requires a special scan tool, is not used at TOYOTA dealers.

        • What is Quick Response (QR) Code?


          • QR code, a matrix symbology consisting of an array of nominally square cells, allows omni-directional, high-speed reading of large amounts of data.

          • QR code encodes many types of date such as numeric, alphanumeric, kanji, kana and binary code. A maximum of 7089 characters (numeric) can be encoded.

          • QR code (2D code) contains information in the vertical and horizontal directions, whereas a bar code contains data in one direction only. QR code (2D code) holds a considerably greater volume of information than a bar code.

    4. Fuel Filter Assembly


      1. A fuel filter assembly consists of a separate filter element and a filter housing.

      2. A paper filter element that offers high filtering efficiency and captures the minutest particles is used.

      3. A fuel filter warning switch is provided in the fuel filter assembly.

      4. On the models for Europe, in order to improve the fuel heating performance, a recirculation type fuel heater is used.

        A01EZO5E01
        Text in Illustration
        *A Models for Europe - -
        *1 Priming Pump *2 Fuel Filter Warning Switch (Vacuum Switch)
        *3 Filter Element *4 Filter Housing
        *5 Fuel Heater *6 Fuel Sedimenter Level Warning Switch

    5. Fuel Cooler (Models Compliant with EURO 5 and EURO 4 Emission Regulations and Models Compliant with EURO 2 Emission Regulations with Variable Nozzle Vane Type Turbocharger)


      1. An air-cooled fuel cooler is used.

      2. The fuel cooler, which is provided in the fuel return path, cools the return fuel that has reached a high temperature as a result of the pumping of the supply pump. This prevents the reduction in fuel viscosity that is caused by the rise in fuel temperature, and improves the reliability of the fuel system.

        A01EZJOE01
        Text in Illustration
        *1 Fuel Cooler *2 Fuel
        *a A - A Cross Section - -
        A01EZJZ To Fuel Tank A01EZFI From Engine

  3. OPERATION


    1. Supply Pump Assembly


      1. Due to the rotation of the eccentric cam, the ring cam pushes plunger "A" upward as illustrated below. The force of the spring pulls plunger "B" (which is located opposite plunger "A") upward. As a result, plunger "B" draws fuel in, and plunger "A" pumps fuel at the same time.

        A01EZATE01
        Text in Illustration
        *1 Check Valve (for Suction) *2 Check Valve (for Discharge)
        *3 Eccentric Cam *4 Plunger "A"
        *5 Ring Cam *6 Plunger "B"
        *7 Suction Control Valve (SCV) *8 ECM

      2. The ECM controls the opening of the SCV in order to regulate the volume of fuel that is pumped by the supply pump to the common-rail. Consequently, the fuel pressure in the common-rail is controlled to the target injection pressure.

      3. When the opening of the SCV is small, the fuel suction area is kept small, which decreases the transferable fuel quantity.

      4. When the plunger strokes fully, however, the suction volume becomes small due to the small suction area.

      5. Pumping will start when the fuel pressure has become higher than the common-rail pressure.

        A01EZEME01

      6. When the opening of the SCV is large, the fuel suction area is kept large, which increases the transferable fuel quantity.

      7. If the plunger strokes fully, the suction volume will increase because the suction area is large.

      8. Pumping will start at the time when the fuel pressure has become higher than the common-rail pressure.

        A01EZCWE01

    2. Injector Assembly (Models Compliant with EURO 5 Emission Regulations)


      1. When current is applied to the piezo actuator, the No. 1 piston, No. 2 piston and three-way valve are pushed down.

      2. The orifice on the upper part of the three-way valve opens and the fuel in the control chamber flows out.

      3. The fuel pressure in the control chamber drops.

      4. As a result, the nozzle needle is pushed up due to fuel pressure, causing fuel injection.

      5. Current to the piezo actuator is shut off and the No. 1 and No. 2 pistons and the three-way valve are pushed up due to spring tension.

      6. The orifice on the upper part of the three-way valve closes to stop fuel flow.

      7. The fuel pressure in the control chamber rises.

      8. As a result, the nozzle needle goes down to stop fuel injection.

        A01EZP3E01
        Text in Illustration
        *1 Injector Assembly *2 Piezo Actuator
        *3 No. 1 Piston *4 No. 2 Piston
        *5 Orifice *6 Three-way Valve
        *7 Control Chamber *8 Nozzle Needle
        *a Return Fuel *b Fuel from Common-rail

    3. Injector Assembly (Except Models Compliant with EURO 5 Emission Regulations)


      1. When electrical current is applied to the solenoid coil, it pulls the solenoid valve up.

      2. The orifice of the control chamber opens, allowing the fuel to flow out.

      3. The fuel pressure in the control chamber drops.

      4. Simultaneously, fuel flows from the orifice to the bottom of the piston and raises the piston up (to enhance response).

      5. As a result, the piston raises the nozzle needle to inject fuel.

        A01EZPHE01
        Text in Illustration
        *1 Injector Assembly *2 Solenoid Coil
        *3 Solenoid Valve *4 Piston
        *5 Nozzle Needle - -
        *a Fuel from Common-rail *b Return Fuel

    4. Fuel Filter Assembly


      1. Fuel Filter Warning Switch


        • When the water in the sedimenter section reaches a certain amount, the fuel sedimenter level warning switch comes on, the warning light in the combination meter assembly illuminates, and the multi buzzer sounds.


        • A fuel filter warning switch, which turns on or off when the internal vacuum of the filter increases, is provided in the fuel filter. This switch, which turns off when the internal vacuum of the fuel filter increases to a predetermined level, is connected by wire to the meter ECU.

          A01EZK4E01

        • When the meter ECU detects that the internal vacuum of the fuel filter has increased (by way of the fuel filter warning switch off signal), it determines that the fuel filter has become clogged. Then, it illuminates the fuel system warning light on the combination meter assembly to urge the driver to replace the fuel filter.

          A01EZK1E02

      2. Fuel Heater (Models for Europe)


        • This heater heats the fuel by recirculating the returned fuel, which is made to have a high temperature by the fuel pumping of the supply pump, to the fuel filter.

          A01EZAGE01

        • While the engine is cold, the recirculation valve inside the fuel heater will open due to the bimetal action, so the return fuel will return to the fuel filter and the fuel tank.


        • While the engine is warm, the recirculation valve will close due to the bimetal action, so all the return fuel will return to the fuel tank.

          A01EZHLE01
          Text in Illustration
          *1 Fuel Heater *2 Recirculation Valve (Bimetal)
          *a

          Cold Engine

          (Recirculation Valve: Open)

          		 *b

          Warm Engine

          (Recirculation Valve: Closed)
          *c To Fuel Filter *d To Fuel Tank
          *e From Supply Pump Assembly - -