FIELD

The present description relates generally to methods and systems for a fuel injector assembly.

BACKGROUND/SUMMARY

Internal combustion engines are equipped with one or more fuel injectors for delivering fuel to the engine for combustion. During certain engine operating conditions, it may be desirable to perform more than one fuel injection. For example, a fuel injection event may be split into three separate fuel injections, such as a pilot injection, a main fuel injection, and a post fuel injection. As such, a pilot fuel injection is performed before the main fuel injection, and is provided to address combustion noise and enhance combustion while a post fuel injection is performed after the main fuel injection, and is provided for improved emission control. Thus, multiple split fuel injections may be performed during a single combustion cycle in order to improve engine performance and reduce emissions.

Fuel injectors are controlled by an engine controller, which provides an actuation signal to the injector for each fuel delivery event, such as the fuel injector described in U.S. Pat. No. 6,705,278. For injecting fuel during split fuel injections, different actuation signals are provided to the fuel injector, wherein the split fuel injections may include a main fuel injection event flanked by fuel pre-injection, and fuel post-injection events.

However, the inventors herein have recognized some issues with the above fuel injector control. As an example, when a time interval between two injections is short, providing an actuation signal for each injection can result in overlapping signals. Consequently, there is a limit on the minimum duration of the time interval. Thus, when short time intervals are desired, providing separate actuation signals for each injection cause variability in the amount of fuel delivered and timing of each fuel delivery event. As a result, engine performance and emission control are compromised. Further, the injector ector cycles through an actuation cycle for each of the split fuel injections. This can cause additional wear and tear on the injector. Still further, as the controller is required to generate a signal for each of the split injections, the controller consumes more resources, thereby decreasing the efficiency of the control system.

In one example, the issues described above may be addressed by a method for a fuel injector, comprising injecting fuel from the fuel injector by displacing a plurality of fuel injector needles of the fuel injector to deliver fuel through a first nozzle coupled to a first fuel chamber, a second nozzle coupled to a second fuel chamber, and a third nozzle coupled to a third fuel chamber during a single actuation cycle of the fuel injector. Each of the first nozzle, the second nozzle, and the third nozzle may be positioned along different vertical planes of a fuel injector body. Multiple fuel injections may be performed in one actuation cycle of the fuel injector to deliver high-pressure fuel from each of the chambers through the coupled nozzles into different locations inside the combustion chamber, resulting in enhanced fuel spray atomization, and reduced fuel spray penetration.

Another example method for a fuel injector may include moving an injector needle from a first position to a fourth position via a second position and a third position, performing a first fuel injection at the second position, a second fuel injection at the third position, and a third fuel injection at the fourth position and subsequently moving the needle from the fourth position to the first position via the third position and the second position, and performing a fourth fuel injection at the third position and a fifth fuel injection at the second position. The first through the fifth fuel injections may be performed during a single cycle of the injector needle movement. Fuel may be injected through a first row of nozzles, a second row of nozzles, and/or a third row of nozzles at each of the fuel injection positions, wherein the first row of nozzles may be positioned vertically lower than the second row of nozzles, and the second row of nozzles may be vertically lower than the third row of nozzles along a fuel injector body.

In this way, multiple fuel injections with quick transition time between consecutive fuel injections may be performed during a single actuation cycle of the fuel injector. Fuel may be injected through fuel injector nozzles located at different vertical planes of the fuel injector body, ensuring optimal fuel distribution and reduced fuel spray penetration. Additionally, injecting high-pressure fuel from the nozzle holes at each position of the fuel injector may increase fuel spray atomization. Fuel spray pattern in combination with quick transition time between consecutive fuel injections during the single actuation cycle may reduce fuel injector wear and tear, enhance combustion efficiency, and reduce harmful emissions.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

