Contents: Differences from previous models ↓ Common rail high pressure fuel line…↓ Pressure pump ↓ Design features ↓ Operating principle ↓ Common rail high pressure fuel line…↓ Maintenance recommendation ↓ Nozzle ↓ Maintenance recommendation ↓ Operating principle ↓ Table 2.13. Technical…↓
Fig. 2.82. Fuel system of a car with a 1CD-FTV engine
Fig. 2.83. Block diagram of the fuel system of the 1CD-FTV engine
To improve maintainability, the fuel line is connected to the fuel hose using a quick-release connector.
Similar to the previous model, the new engine uses a common rail injection system (common-rail).
Differences from previous models
To increase power and reduce exhaust emissions at high engine speeds, the new Corolla Verso features a common rail fuel injection system (Common-Rail), providing high pressure in the fuel system. In this regard, the following changes have been made to the fuel system design:
- modified common rail fuel distribution (Common-Rail), injection pump and nozzles;
- pressure limiter excluded;
- a relief valve is installed.
Common rail high pressure fuel line – Common-Rail
In this system, fuel under high pressure, created by the injection pump, is in the common rail. The engine ECU sends signals to the injectors via the electronic control unit of the powertrain, regulating the moment of injection and the amount of fuel injected.
Pressure pump
Fig. 2.84. Injection pumps of the current and previous models
Instead of a 4-plunger injection pump type HP2 of traditional design (with internal cam) the 1CD-FTV engine is equipped with a 2-plunger NRZ with an external cam. As a result, the pump has become more compact, its overall length has been reduced (Fig. 2.84).
The publication is taken from the website (ToyotaMan.ru)
Design features
Fig. 2.85. Design of the injection pump
The injection pump consists of an eccentric shaft, a cam, two plungers, four check valves and a fuel control valve (SCV), a fuel temperature sensor and a feed pump.
The cam actuates two plungers located opposite each other.
Operating principle
Fig. 2.86. Operation diagram of the injection pump
When the eccentric shaft rotates, the cam moves plunger A to the right, as shown in Figure 2.86. Plunger B (located opposite plunger A) under the action of the spring also moves to the right. As a result, plunger B sucks in and plunger A displaces fuel into the line.
Common rail high pressure fuel line – Common-Rail
Fig. 2.87. Common high-pressure fuel rail
The common high-pressure fuel rail serves as a reservoir for the fuel pumped by the high-pressure pump. The common fuel rail is equipped with a fuel pressure sensor and a relief valve that regulates the fuel pressure in the common fuel rail.
The Common Rail line consists of a main reservoir from which five pipes exit. The reservoir is connected to the pipes by 1 mm diameter holes that dampen pressure fluctuations in the fuel system.
The plunger in the relief valve opens and closes in accordance with control signals from the electronic powertrain control unit (EDU), thereby regulating the pressure in the common rail. In addition, a pressure relief function is provided in the event of an accident.
Maintenance recommendation
The fuel pressure sensor has a sealing section (plastically deformable when the sensor is installed), which ensures the tightness of the connection between the sensor and the fuel line; the sealing section cannot be reused after the sensor is removed.
When replacing parts that affect the alignment of the unit connections, install a new high-pressure fuel pipe. Below is a list of such parts.
A new high-pressure fuel line is installed when replacing: an injector, a common fuel line, a cylinder head.
A new fuel supply pipe to the common fuel line is installed when replacing: the injection pump, the common fuel line, the cylinder block, the coolant pump, the cylinder head.
Nozzle
Fig. 2.88. Nozzle design
The design of the injector includes: a spray needle, a plunger and a solenoid valve.
Each injector has its characteristics indicated in the form of a correction value and a QR code.
The injector markings contain various information, such as the model code and correction values for the electronic control unit that sets the volume and start time of fuel injection.
Maintenance recommendation
When installing a new engine ECU, you should record the correction values of all 4 injectors using the microprocessor tester P. When installing new injectors, you should enter their correction values into the engine ECU. The control unit will calculate the corrections correctly, and the accuracy of fuel delivery will not decrease after replacing the injector.
To read the QR code, a special scanner is required, which is not used by Toyota dealers.
The QR code is a graphical combination of square cells that encode a large amount of information.
In a QR code, information is encrypted in various forms (digital, alphanumeric, kanji, kana and binary). This type of encoding allows you to encrypt up to 7089 characters.
QR code (two-dimensional) contains data both vertically and horizontally, whereas a barcode contains information in only one direction. Therefore, a QR code (two-dimensional) is a much more capacious means of recording information than a barcode.
Operating principle
Fig. 2.89. Operating principle of the fuel injector
- a. When electric current enters the solenoid valve coil, the core is pulled upward.
- b. The needle valve of the control chamber opens the channel through which fuel begins to flow.
- c. The pressure in the control chamber drops.
- d. At the same time, fuel flows through the hole under the plunger and lifts it up (response time is reduced).
- e. As a result, the nozzle needle, connected to the plunger, rises and fuel is injected.
Table 2.13. Technical characteristics of injection pumps (engine 1CD-FTV)
