Stanly, R., Parameswaran, G., and Rajkiran, R., "Effect of Fuel System Coking on Vehicle Performance and Spray Field," SAE Technical Paper 2017-01-5017, 2017.
Conventionally, influence of injector coking deposits has been studied using accelerated coking methods. For this work we used in-use vehicles fitted with Common Rail Direct injection (CRDi) injectors in “as-is where is” condition with considerable coked injector deposits. They were then cleaned with a commercial fuel system cleaning solution which did not require the removal of injectors; the influence of injector deposits on vehicular performance and spray field were studied. It was observed that the removal of coking deposits resulted in an increase in the peak power of the vehicle, a lower fuel injected quantity and lower fuel injection duration. It was also observed that the fuel system cleaning procedure resulted in better atomization of fuel spray, better uniformity of the multiple spray jets and an increase in the flow rate of the test injectors. The perceived improvements in performance and spray field were credited to the removal of coking deposits which was established by a decrease in the weights of injector nozzles and needles after the cleaning process.