Ultrasonic rinsing with dismantling nozzles primarily applied to the injectors, and the key point here is the use of ultrasound technology. After the initial inspection of nozzles on the stand before ultrasonic cleaning it is recommended to blow each nozzle with compressed air at low pressure (1-1.5 bar) to remove any remaining liquid and exfoliated debris from the nozzle before starting the following procedure.
Parts to be cleaned (this may be not only the nozzle but also carburetors, fuel pumps, and not only fuel system parts – candles, pistons, valves, etc.) are placed in a bath in a special solution, subjected to ultrasound from 15 for 30 min (depending on the degree of contamination, the bath characteristics and the applied fluid). The equipment may vary – accordingly, the output quality may differ. Those looking for quality typically take advantage of Hilsonic level equipment; the UK-based company is considered to be one of the leading ultrasonic cleaner manufacturing players.
However, in nozzles, unlike in other parts, there are certain things you should keep in mind – it is highly desirable to let them ‘work’ during the process of purification, that is, opening and closing the valve. For this purpose, the stands cleaning nozzles are provided control units which supply signals to the injectors at a predetermined frequency and duration (emitting, respectively, the desired engine speed and fuel injection time).
Cleaning efficiency is increased if the cleaning liquid is subjected to heat. For quality cleaning small enough power ultrasonic transducer bath – 50-100 W with a bath volume of 1.5-2 liters. The most common bath designed for the amplitude modulation frequency of 20-44 kHz ultrasonic vibration.
Ultrasonic cleaning is effective at any level of contamination (with high degree of contamination, this method is generally indispensable). In most cases, as a result of ultrasonic cleaning can achieve factory parameters of the injectors.
Complementing the innovations with conventional technologies
Rinsing and/or spraying is typically carried out on a special stand, which is usually combined with a stand injector test. The control system of the stand simulates the injectors on the engine with the only difference that instead of the fuel flowing through wash liquid is applied. An operator manipulating the frequency of electric oscillations injector valve achieves occurrence in the fuel supply passage cavitation – the formation of air bubbles in the liquid. This results in more effective destruction of contaminants. The moment of cavitation is determined visually – the coming out of the nozzle jet fuel becomes brown because of losing slag. Again, the fact should be underlined that this method is better used as an additional or extra measure (ultrasound is a more powerful technology here).
Also, some boards have the function of so-called backwash – nozzles installed on the stand ‘upside down’ and the quality of them washed away the remnants of deposits remaining after the application of other methods (such as ultrasonic cleaning). Typically, backwash function applies only to the nozzles from the top of the fuel supply.