SMAC moving coil actuators are helping a world-leading manufacturer of diesel injectors to reduce emissions by using an actuator to determine the spring characteristics in its injectors. The standard SMAC characteristics of programmable force control coupled to submicron resolution professional encoder feedback ensures that the measurement of spring rates and deflection are carried out with great accuracy and repeatability.
An essential characteristic in any diesel injector is achieving a constant spring rate in the valve head of the injector. This accuracy of this spring rate has a direct effect on emissions which is crucial in today's climate.
This is achieved by applying a constant load on the spring and measuring deflection.
Once the deflection is determined a compensating shim is added to achieve the correct performance. The tolerances on the setting of the spring rates are becoming tighter due to better vehicle performance and emissions regulations.
The traditional method of achieving this was to use a servomotor,ballscrew, manufacturer of load cell and LVDT. Predictably this led to a significant stack up of errors and a single device capable of force and position feedback was essential to meet the latest specifications. SMAC's LAL300 & LAL500 are used for the measuring system. The measurement data reported are used to specify the correct-sized shim which is then fitted to the spring and valve assembly to guarantee correct spring rate. The implementation of the SMAC actuators has led to an immediate and significant increase in quality and reduction in rejects.
