Conversion of non-accumulator-type hydraulic electronic unit injector to accumulator-type hydraulic electronic unit injector

摘要

A non-accumulator-type hydraulic electronic unit injector assembly can be converted to an accumulator-type hydraulic electronic unit injector assembly simply by subjecting the nozzle needle of the injector to downwardly closing forces arising from fluid pressure in the high pressure chamber of the intensifier. This modification causes the needle to remain seated upon intensification of fluid pressure in the high pressure chamber and permits fuel injection to commence only upon subsequent pressure decay in the high pressure chamber. An accumulator volume is formed beneath the blowback avoidance check-valve of the converted injector and can, if necessary, be enlarged by adding the spring chamber of the assembly to the accumulator volume. The resulting assembly could conceivably be retrofitted into an existing injection system on site, or could be assembled as new construction using primarily stock non-accumulator-type assembly components. Manufacturing expenses can thus be sharply reduced, thereby promoting retrofitting, low-volume production, and/or standardization.