Contents: Siemens-Fenix 3 central injection…🠛 Siemens-Fenix 5 Semi-Sequential…🠛 Siemens-Fenix 5 sequential…🠛
Siemens-Fenix 3 central injection system
Models 1.4 l (e7J engines) equipped with a Siemens-Fenix 3 central fuel injection system with a Bosch throttle body. The system includes a catalytic converter and a fuel vapor recovery system.
The fuel pump delivers fuel from the tank to the injectors, through a filter mounted at the rear of the vehicle. Fuel delivery pressure is controlled by a pressure regulator, which is mounted in the throttle body assembly.
The electrical control system consists of an electronic control unit (ECU), along with the following sensors:
- a) Throttle potentiometer - provides the electronic control module with information about the position of the throttle valve and the degree to which it is opened.
- b) Coolant temperature sensor - provides the electronic control module with information about the engine temperature.
- c) Intake Air Temperature Sensor - Provides the electronic control module with information about the temperature of the air passing through the throttle body.
- d) Lambda sensor - provides the electronic control module with information about the oxygen content in the exhaust gases.
- e) Micro switch (included in the idle speed control stepper motor) - provides the electronic control module with information about the throttle valve closing (that is, when the gas pedal is released).
- f) Crankshaft Speed/Position Sensor - Provides the electronic control module with information about engine speed and crankshaft position.
- g) Power steering pressure sensor - provides the electronic control module with information about the use of the power steering pump, the module increases the idle speed.
- h) Knock sensor - provides the electronic control module with information about engine load by monitoring the pressure in the intake manifold.
- f) Vapor recirculation valve - controlled by the fuel vapor recirculation system.
All of the above information is analyzed by the ECU, which then adjusts the ignition timing and fuel delivery to the engine. The ECU controls the operation of the injectors by changing the injection duration (period during which the injector is open), to enrich or lean the mixture as needed. The ECU constantly adjusts the mixture ratio to ensure the best engine performance in different modes.
The ECU also controls idle speed via a stepper motor mounted in the throttle body. The motor's pushrod rests against a cam on the throttle shaft. When the throttle is closed (the gas pedal is not pressed), The ECU uses the motor to change the position of the throttle valve and thus regulate the idle speed.
The ECU also controls the operation of the exhaust gas recirculation and fuel vapor recovery systems.
If one of the sensors fails, the ECU activates the source memory block, which contains the regulated values of all factors. In this case, the ECU ignores the incorrect sensor signal and replaces it with the value taken from the memory block. If the ECU accesses the source memory block, the control lamp lights up on the instrument panel and the corresponding fault code is stored in the ECU memory.
Material taken from an online portal RenaultBook
If the warning light comes on, contact a Renault service station as soon as possible, which will perform a full diagnosis of the engine management system using a special electronic tester (XR25), which is simply plugged into the diagnostic connector (mounted on the fuse box on the dashboard).
The fuel cut-off switch is built into the fuel injection system. In the event of an accident, the switch cuts off power to the fuel pump, thus preventing fuel spillage if the fuel lines break.
Siemens-Fenix 5 Semi-Sequential Multipoint Injection System
The K7M engines are equipped with a semi-sequential distributed fuel injection system with a Pierburg throttle body. This system is basically similar to the central injection system described in the previous paragraphs, except that there are four injectors in the intake manifold (one per cylinder). All injectors are fed from a common fuel line equipped with a fuel pressure regulator.
In a semi-sequential injection system, the injectors operate in pairs (1 and 4, then 2 and 3). During one revolution of the engine, fuel is injected into each cylinder once, that is, during a complete 4-stroke cycle, fuel is injected into the cylinders twice.
The system has an exhaust gas recirculation valve.
On models with automatic transmission, information from sensors on the transmission is sent to the electronic control module for processing to determine the most efficient settings for the engine.
Siemens-Fenix 5 sequential distributed injection system
The F3R and F7R engines are equipped with a sequential multipoint injection system with a Solex (F3R) or Magneti Marelli (F7R) throttle body. This system is most similar to the central injection system described earlier, except that it has four injectors (one per cylinder), installed directly in the intake manifold or in the cylinder head. All injectors are fed from a common fuel line, which also has a fuel pressure regulator.
In a sequential injection system, the injectors operate separately. The combined signal from the camshaft position sensor and the crankshaft speed/position sensor is used by the electronic control module to determine engine speed, crankshaft position and cylinder stage. And information about engine speed and piston position relative to TDC comes from the crankshaft speed/position sensor; information about which of the two pistons is at TDC during the compression stroke comes from the camshaft position sensor. Based on this data, the electronic control module is able to determine the moment of the start of fuel injection for each cylinder separately. Other information from additional sensors allows the electronic control module to calculate the injector open time depending on the temperature, speed and engine load.
On models with the F7R engine, the system also includes an exhaust gas recirculation valve.
On F7R models, to provide the necessary intake air flow at low engine speeds to produce sufficient torque, and at high engine speeds to produce sufficient power, a dual-flow intake manifold is used. That is, there are two separate, parallel-operating intake ducts controlled by a damper and an electromagnetic unit. Depending on engine speed, one of the two intake ducts will be opened or closed, providing the required air flow in all operating modes.