Fuel Injector
| ITEM | DESCRIPTION |
|---|---|
| 1 | Electrical connection to the Powertrain Control Module (PCM) |
| 2 | Low Pressure (LP) fuel leak-off connection to the fuel filter |
| 3 | Data matrix and injector information |
| 4 | High Pressure (HP) fuel supply connection from the fuel rail |
The four fuel injectors are of the solenoid actuated type, each manufactured with eight spray holes in the injector nozzle. The injectors are located centrally within the cylinder head combustion chambers to spray atomized fuel directly onto the toroidal dome of the pistons.
There are two types of injectors available. One for the Ingenium I4 2.0L diesel 180 PS and one for the 240 PS engine variant. These are differentiated by the nozzle flows, see table below.
| OPERATING PARAMETER | VALUE |
|---|---|
| Supply voltage | 6 V to 16 V 230 bar (3, 336 lbf/in2 ) to 1, 800 bar (26, 107 lbf/in2 ) |
| Resistance | Nom 0.39 ohms at 20°C (68°F) |
| Maximum capable delivery - 180 PS engine | 400 cm3 /30 sec at 100 bar (1, 450 lbf/in2 ) |
| Maximum capable delivery - 240 PS engine | 530 cm3 /30 sec at 100 bar (1, 450 lbf/in2 ) |
During manufacture, each injector is tested to measure the actual injected quantity of fuel, compared to a reference quantity for simulated conditions. The tests are used to categorize the injectors. The difference in the injection analysis results is translated to a seven digit alpha-numerical code that is etched on the injector casing.
The seven digit codes are stored in the Powertrain Control Module (PCM) memory along with the corresponding cylinder numbers for each injector and an engine performance software map. The PCM recognizes each injector seven digit code and adapts the operation of each injector. This makes sure that similar injection pressures and quantity of delivered fuel are provided for the current operating condition, in accordance with the programmed software map.
The injector body contains a solenoid actuator mounted on the top of the injector. The solenoid is actuated by a supply voltage from the PCM. Upon actuation of the solenoid, a pressure difference is generated within the injector which causes the needle in the injector to move and injection event to occur.
The Bosch common rail fuel system technology and the injector hydraulic chamber allow the injector to operate with near instantaneous response times to PCM commands. This provides a finer atomization of the injected fuel and allows the PCM to precisely control the actuation period of the injector. During certain engine operating conditions, each injector is able to deliver a sequence of up to five injections during a single injection cycle.
A typical sequence for an injection cycle of five individual deliveries is as follows:
- Two pilot injections
- One main injection
- Two post-injections during the Diesel Particulate Filter (DPF) regeneration phase.
The pilot injection phase is delivered ahead of the main charge of fuel. This produces a steady flame front and create a progressive pressure rise in the cylinder. The pilot injection phase reduces the lag between the injection of fuel and combustion occurring. This allows the remaining charge of fuel to be injected while combustion is taking place. This injection principle can be used to reduce combustion Noise, Vibration and Harshness (NVH) and exhaust emissions.
On vehicles installed with an exhaust system DPF, the High Pressure (HP) fueling system provides a post-injection phase of fuel into the combustion chambers. During the regeneration stage of the DPF, the PCM allows fuel to be injected after the combustion stroke and into the commencement of the exhaust stroke. The post-injection phase causes fuel to burn in the exhaust system, creating high exhaust gas temperatures required to regenerate the DPF. For additional information, refer to: ELECTRONIC ENGINE CONTROLS