Deposits forming in the injector nozzle holes of modern diesel cars can reduce
and disrupt the fuel injected into the combustion chamber, causing reduced or
less efficient combustion, resulting in power loss and increased fuel
consumption.
A study of the factors affecting injector nozzle tip temperature, a parameter
critical to nozzle deposit formation, has been conducted in a Peugeot DW10
passenger car bench engine, as used in the industry standard CEC F-098 injector
nozzle deposit test, [1].
The findings of the bench engine study were applied in the development of a
Chassis Dynamometer (CD) based vehicle test method using Euro 5 compliant
vehicles. The developed test method was refined to tune the conditions as far as
practicable towards a realistic driving pattern whilst maintaining sufficient
deposit forming tendency to enable test duration to be limited to a reasonable
period.
The test method developed was applied to a fleet of Euro 4 and 5 compliant
vehicles enabling the relative deposit sensitivity of the fleet to be assessed.
Subsequently the deposit removal performance of conventional and novel diesel
detergents was evaluated using the method developed.
Most of the fleet selected was susceptible to nozzle hole deposit formation and
in all cases where deposit formation was detected, the novel diesel detergent
outperformed the conventional detergent in recovering power and fuel efficiency
losses due to deposit formation.
This work has provided insights into the susceptibility of modern diesel
passenger vehicles to injector nozzle deposit formation and removal using a test
method that is more realistic and widely applicable than industry standard
methods.
