Which type of diesel fuel injector is characterized as having inward and outward opening mechanisms?

Pencil fuel injectors are specifically designed with inward and outward opening mechanisms, allowing them to effectively atomize fuel during the injection process. This type of injector is known for its compact size and efficiency, making it particularly suitable for applications requiring precise fuel delivery and better combustion efficiency. The inward opening mechanism helps draw fuel into the injector, while the outward opening enables the precise discharge of fuel into the combustion chamber at the appropriate time, promoting better mixing of air and fuel for improved engine performance.

Swirl fuel injectors are designed to create a swirling motion in the fuel, optimizing mixing and combustion but do not employ the inward and outward opening mechanism characteristic of pencil injectors. Common rail injectors utilize a different approach, relying on high-pressure fuel supply to operate but do not fit the definition of having both inward and outward mechanisms. Electronic fuel injectors are controlled electronically to achieve fuel delivery, but they too do not operate based on the inward and outward design that defines pencil injectors.