A Study of Knock in Lean-Burn Spark-Ignition Engines 921668

A study on the onset of knock in dilute spark-ignition engines was conducted on a Ricardo E6 variable compression engine. The combustion chamber was of the disc type providing the very basic shape of chambers. Various operating parameters were considered viz: equivalence ratio, engine speed, ignition timing, inlet air temperature and inlet air pressure. The onset of knock was defined by a piezo-electric pressure transducer while knock was characterized by ‘knock-limited compression ratio’. In some experiments, perforated disc-type turbulence generators with different blockage ratios were fitted immediately before the inlet valve; the object being to enhance in-cylidner turbulence and thus the effect of such turbulence augmentation on knock limit was experimentally defined. Correlations were developed to enable the onset of knock to be predicted which read:
No Caption Available
for a gasoline with an octane number of 90. and
No Caption Available
for a gasoline with an octane number of 80.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 40% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.