Search Results

A study on the effect of induction manifold angles in tumble induced turbulence on detonation and pre-ignition in spark-ignition engines was conducted on a Ricardo E6 variable compression engine. A new cylinder head was designed and manufactured with four induction manifold inserts with angles of 30°, 40°, 50° and 60° in addition to the original angle of 90°. The onset of pre-ignition and detonation were defined by a piezo-electric pressure transducer. Knock was characterized by the “knock-limited compression ratio” concept. However pre-ignition was characterized by the input electrical power consumed by a pre-igniter acting as an artificial hot spot. A set of experiments were carried out on each induction manifold to cover the effect of the design and operating parameters of the engine on detonation and pre-ignition.

Jojoba bio-diesel is one of the most promising bio-fuels to replace gas oil in diesel engines. Therefore, the main object of the present work was to measure and correlate the pressure rise ignition delay of jojoba bio-diesel and its blends with gas oil behind incident shock waves in a shock tube. For this purpose, a shock tube test set up was designed and manufactured. It was fully instrumented for delay measurement with two piezo-electric pressure transducers, dual mode charge amplifier, data acquisition card and a computer with suitable LabVIEW software. The test variables included the type of fuel (percentage of Jojoba bio-diesel in the blend with gas oil), equivalence ratio, ignition temperature and ignition pressure. It was found that jojoba bio-diesel exhibited a lower ignition delay in comparison with that of gas oil. Rich or lean mixtures produce long delays, whilst the minimum delay occurred near the stoichiometric mixture.