EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF WATER ADDITION INTO THE INTAKE AIR ON COMBUSTION PARAMETERS, ENERGY BALANCE AND DEVELOPING AN EMPIRICAL COMBUSTION DURATION RELATION IN AUTOMOBILE DIESEL ENGINE

Abstract

The effect of the water addition into the intake air (WAIA) on cylinder pressure, temperature, heat release rate (HRR), combustion duration (CD), and energy balance in an automotive diesel engine have been investigated experimentally. Also, an empirical correlation has been developed for estimating CD using the HRR. This relation has been developed by applying the multiple curve fitting method, taking into account experimental results for different water ratios such as (2, 4, 6, 8, and 10) %, different engine loads, and different engine speeds such as (2000, 2500, 3000, 3500, and 4000) rpms. The test results showed that cylinder pressure values generally increased at (2000, 2500, and 3500) rpm, but they decreased at (3000 and 4000) rpm for all of the selected water ratios. Also, maximum cylinder temperature values have occurred at crank angles farther from TDC for WAIA. Cylinder temperature values mostly decreased at (2000, 2500, and 3000) rpms, but they generally increased at (3500 and 4000) rpms for WAIA. Also, maximum cylinder temperature values were occurred at crank angles farther from TDC for WAIA. HRR values generally decreased at (2000, 2500, 3500, and 4000) rpms, but they generally increased at 3000 rpm. It has been determined that the CDs were generally shortened at all of the engine speeds under full loads with water addition. CD values for NDF and (2.42, 4.22, 5.95, 8.32, 9.46) % water ratios have been determined as (13.10, 12.96, 12.93, 12.68, 12.95, and 13.576) °CA, respectively, at 2000 rpm. The effective power values according to the chemical energy of the fuel generally decrease with WAIA at 2000 rpm. However, the effective power values according to the chemical energy of the fuel increase for high WRs at 4000 rpm.