Some Series 40E electronic engines are equipped with split-shot injectors. On these injectors the injection cycle is executed in two stages. Some fuel is pre-injected into the combustion chamber to initiate the combustion and, once initiated, the primary injection takes place. This feature reduces emission levels at light load operations. It also reduces light load engine noise.
Both the electrical and the hydraulic portions of the split-shot injector operate identically to the regular HEUI injector, but the fuel distribution is different.
The barrel and plunger were redesigned and a spill port was incorporated. When injection is initiated, the first shot of fuel is pre-injected into the combustion chamber until the spill port of the plunger coincides with the slot on the barrel.
At this time some fuel is allowed to return back to the fuel supply port until the spill port slot is blocked again by the plunger and the primary injection stroke takes place. See Figure
“HEUI Split-Shot Injector Operation”
Figure 1. HEUI Split-Shot Injector Operation
|Series 40E Troubleshooting Manual – 6SE241|
|Generated on 10-13-2008|