An experimental work is performed in a constant volume combustion chamber to study the effect of varying hot surface temperature on ignition delay characteristics for different fuel sprays (Hollow cone spray and Solid cone spray). For ejecting the sprays pintle and single hole nozzles were used. In this experimental work hot surface temperature (HST) varied from 350°C to 550°C, air pressure inside the cylinder varied from 10 to 25 bar while fuel injection pressures varied from 10 to 20 MPa. Optical method is used for detecting the flame appearance while a digital Oscilloscope is used to measure ID of sprays by recording the gap between injection event and the event of appearance of flame. During the work it is found that ID is strong function of HST rather than other operating parameters. It is also found that on increasing HST, for both sprays ignition delay is decreasing at every injection pressures.

Ignition delay is very important parameter which influences the entire combustion process and emissions generated inside the engine. An experimental study was conducted to observe the variation in ignition delay with changing environment inside the combustion chamber for different sprays. Two types of nozzles namely pintle nozzle and single hole nozzle were used for creating hollow cone spray and solid cone spray respectively. This study was carried at different injection pressures (100 bar, 150 bar and 200 bar), different HST (350°C, 450°C and 550°C) and different air pressures (10 bar, 15 bar, 20 bar and 25 bar) for obtaining the value of ID. A digital Oscilloscope is used to record ID and optical method was used for detecting the flame. Results of the experiments show that air pressure, injection pressure and HST all are responsible for variation in ID but HST is more strongly affect the ID compared to other parameters. However at high value of HST and injection pressures variation in ID is less. Variations in the values of ID are more for Solid cone spray than Hollow Cone spray although ID is decreased for both sprays at almost all injection pressures. The dependency of types of spray is more prominent in lower temperature ranges compared to higher temperature ranges.