Injection begins when the upper fuel port is covered by the upper helix of the downward moving plunger, and injection ends when the lower fuel port is uncovered by the lower helix of the downward moving plunger.

Injection begins when the lower fuel port is covered by the lower helix of the downward moving plunger, and injection ends when the upper fuel port is uncovered by the upper helix of the downward moving plunger.

Injection begins when the upper fuel port is covered by the upper helix of the upward moving plunger, and injection ends when the lower fuel port is uncovered by the lower helix of the upward moving plunger.

Injection begins when the lower fuel port is covered by the lower helix of the upward moving plunger, and injection ends when the upper fuel port is uncovered by the upper helix of the upward moving plunger.