Theoretical Relationship Between Combustion Pressure and Engine Vibration

Effect of biomethane substitution on combustion noise and performance of a dual fuel common rail direct injection diesel engine

“…At full load conditions (49.5 Nm), the slope of decrement (101.74–99.74 dB) in the noise level with increasing z value is lower due to higher in‐cylinder pressure. Intensity of noise high frequencies are affected by the shape of cylinder pressure diagram whereas peak cylinder pressure is a deciding factor for low frequency range and delay in ignition will also result in higher noise levels 77–79 . The cylinder pressure spectra for methane augmented dual‐fuel CRDI engine at different loading conditions with increasing share of methane energy are as detailed in Figure 7, where it can be observed that there are no changes in the curve at low frequency composition for all operating conditions.…”

“…At full load conditions (49.5 Nm), the slope of decrement (101.74-99.74 dB) in the noise level with increasing z value is lower due to higher in-cylinder pressure. Intensity of noise high frequencies are affected by the shape of cylinder pressure diagram whereas peak cylinder pressure is a deciding factor for low frequency range and delay in ignition will also result in higher noise levels [77][78][79]. The cylinder pressure spectra for methane augmented dual-fuel CRDI engine at different loading conditions with increasing share of methane energy are as detailed in Figure7, where it can be observed that there are no changes in the curve at low frequency composition for all operating conditions.F I G U R E 6 Effect of methane substitution on (a) peak pressure and location of peak pressure, and (b) sound pressure level at different engine operating conditions F I G U R E 7 Effect of methane substitution on the cylinder pressure spectra at (a) 3% (1.5 Nm), (b) 24% (13.5 Nm) and (c) 44% (24 Nm) (d) 90% (49.5 Nm) loading conditions at 1800 rpm F I G U R E 8 Effect of methane substitution on the rate of pressure rise at (a) 3% (1.5 Nm), (b) 24% (13.5 Nm), (c) 44% (24 Nm), and (d) 90% (49.5 Nm) loading conditions at 1800 rpm F I G U R E 9 Effect of methane substitution on the second derivative of the cylinder pressure (or P) at (a) 3% (1.5 Nm), (b) 24% (13.5 Nm), (c) 44% (24 Nm), and (d) 90% (49.5 Nm) loading conditions at 1800 rpm…”