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http://dx.doi.org/10.9725/kts.2021.37.5.172

Selection of Optimum Clearance Considering the Dynamic Behavior of a High-pressure Injector  

Ryu, Daewon (Graduate School, Dept. of Mechanical Engineering, Yeungnam University)
Kim, Dongjun (Graduate School, Dept. of Mechanical Engineering, Yeungnam University)
Park, Sang-Shin (School of Mechanical Engineering, Yeungnam University)
Ryu, Bongwoo (Hyundai Kefico)
Publication Information
Tribology and Lubricants / v.37, no.5, 2021 , pp. 172-178 More about this Journal
Abstract
An injector is a mechanical device present inside the engine. Its main function is to supply an appropriate volume of fuel into the combustion chamber, which is directly related to the overall engine efficiency of a car. During the operation of an injector, a magnetic force lifts the parts of the injector from closed position to open position which generates a horizontal force on the needle. The horizontal force acts on a different position from that of the center of mass of the needle. Therefore, this causes eccentricity in the needle and the generation of a tilting motion during the lifting operation which can result in wear. However, appropriate selection of clearances for these parts can prevent wear. In this study, lubrication analysis is conducted to determine the optimum clearance of parts with sliding motion inside the injector. The height functions are derived considering the dynamic behavior and relative velocity of the parts. Using the derived height function, the pressure profiles are calculated for the lubricated surfaces from the Reynolds' equation. Subsequently, the fluid reaction forces are calculated. The equations of motions are applied to the fluid reaction forces and external forces are solved to calculate the minimum film thickness between each part with variation in the clearances. Finally, the optimum clearances are determined. The effect of the clearances on the behavior of the moving parts is presented and discussed.
Keywords
clearance; dynamic behavior; height function; high pressure injector;
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Times Cited By KSCI : 1  (Citation Analysis)
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