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Tappet Component Test Rigs

Reduction of friction and wear in the cam/bucket tappet contact of the valve train

nocken_stoessel.jpgCoatings, such as amorphous carbon layers (DLC), in combination with lubricant additives or microstructures specifically applied to the component surfaces can help to improve the friction and wear behavior of the cam/bucket tappet contact in the valve train. The surface modifications must be specifically designed for the existing load spectrum. In addition to a simulation-based approach, the focus is on tests on component test rigs to investigate the operating behavior under application-related conditions.
For this purpose, the KTmfk has two tappet component test rigs, which were developed in-house for research purposes and with the aid of which the operating behavior can be investigated quickly and with good transferability. This is achieved by a reduced representation of the valve train in the form of a single bucket/cam contact. The test rigs are characterized by a modular design which allows the use of standard components (cams, tappets, valves, valve springs).

Tappet friction tester

tsrp.jpgThe tappet friction test rig is used for short-term tests to determine the friction behavior in the operating states of a cam/bucket tappet contact. For this purpose, the friction and normal forces in contact, the applied torque, the speed and the cam angle position are recorded separately and with time resolution during the defined measuring ramps. In addition, the tappet friction tester has a resistive measuring system for monitoring the lubrication condition. The test rig allows speeds of up to 4 000 min-1. The contact is lubricated with adjustable flow rate via an oil unit whose reservoir can be kept at a constant temperature of up to 120 °C.

Tappet friction test rig

tsvp.jpgThe tappet friction test rig allows the performance of long-term tests to investigate the wear behavior in the operating states of a cam/tappet contact. Wear is quantified ex-situ by suitable structural and surface analysis. In addition, the applied torque is recorded with time resolution during the measuring ramps. The test rig allows speeds of up to 4 000 min-1 and the contact is lubricated with adjustable flow rate via an oil unit with temperature control in combination with a pipe heater. This enables a contact temperature of up to 120 °C.