Piston Related Noise with Diesel Engines Parameters of Influence and Optimization

A CWT-based methodology for piston slap experimental characterization

“…On the other hand, the RMS value relative to sensor C presents meaningful differences between Configurations I and II in all the test conditions (close to 20-30%). Moreover, it has to be noted that the percentage difference becomes smaller at higher speed; this behaviour is expected because the piston slap phenomenon is more conspicuous at low speed [28] since other vibration sources are relatively less apparent. Considering these results, the RMS value of the accelerometer placed on the outer cylinder wall is an effective tool to detect the optimal configuration since it is more sensitive to design modifications.…”

“…Transducers have been placed on the thrust side and on the anti-thrust side (see Figure 5) since the propagation path that involves the engine block mainly concerns the piston slap [5] whereas the cylinder head is a preferential propagation path for combustion shocks. Only the transversal acceleration is taken into account since it represents the most significant direction for the study of piston the slap phenomenon [5,9] predominant at cold start and low speed [28]. For this reason, the experimental tests have been performed with engine in cold conditions.…”

Finite element analysis of a composite piston for a diesel aircraft engine

“…The thermal loading of the piston and the resulting temperature profile affect the operation of the drive unit. In diesel engines, the temperature profile in the combustion chamber is largely dependent on the number and orientation of injection holes, injection pressure, injection time, and the geometry of the piston crown [4,5]. In the case of exceeded permissible of maximum temperature, loss of fatigue strength of the piston material and plastic changes may occur.…”