Effect of relative humidity on water injection technique in downsized spark ignition engines
Journal article, 2021

Combustion knock is a major barrier to achieving high thermal efficiency in spark ignition engines. Water injection was
recently identified as a potential way of overcoming this barrier. To evaluate its general applicability, experiments were
performed on a downsized three-cylinder spark ignition engine, varying the humidity of the intake air, the water injection
timing, and the engine speed. The minimum quantity of injected water required to maintain a given load (and thus level
of engine performance) was determined under each set of tested conditions. The knock-suppressing effects of water
injection were found to be related to changes in the fuel–air mixture’s specific heat ratio (kappa) rather than evaporative
cooling, and to therefore depend on the total quantity of water in the cylinder rather than the relative humidity per se.
The total quantity of water in the cylinder was also shown to be a key determinant of advancement in combustion phasing
and particulate emissions under various conditions.

particulates

Water injection

water content

humidity

downsized spark ignition engine

Author

Jayesh Khatri

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Nikhil Sharma

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Petter Dahlander

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Lucien Koopmans

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

International Journal of Engine Research

1468-0874 (ISSN)

Vol. 22 7 2119-2130

High efficient hybrid powertrain

Swedish Energy Agency (43325-1), 2016-12-01 -- 2019-12-31.

Subject Categories

Other Mechanical Engineering

Applied Mechanics

Transport Systems and Logistics

Areas of Advance

Transport

Infrastructure

Chalmers Laboratory of Fluids and Thermal Sciences

DOI

10.1177/1468087420940854

More information

Latest update

10/17/2022