Effect of Oxyhydrogen Injection on Particulate Matter Characteristics in Ethanol-Fuelled Gasoline Direct Injection Engines

¹ College of Industrial Technology, King Mongkut’s University of Technology North Bangkok, Bangsue, 10800 Bangkok, Thailand
² Research Centre for Combustion Technology and Alternative Energy (CTAE), Science and Technology Institute, King Mongkut’s University of Technology North Bangkok, Bangsue, 10800 Bangkok, Thailand
³ Department of Ordnance Engineering, Chulachomklao Royal Military Academy, 26001 Nakhon Nayok, Thailand
⁴ Department of Mechanical and Automotive Engineering Technology, Faculty of Engineering and Technology, King Mongkut’s University of Technology North Bangkok (Rayong Campus), 21120 Rayong, Thailand

^* Corresponding author: kampanart.t@cit.kmutnb.ac.th

Abstract

This research examines the influence of HHO gas, produced through electrolysis, on particulate matter emissions and combustion efficiency within a GDI engine under steady-state operational conditions. HHO, which consists of a composite of hydrogen and oxygen, was injected at varied concentrations (0.5%, 1%, and 2%) into the engine’s intake system to optimize combustion attributes. The findings indicated that the incorporation of HHO resulted in a reduction of total particulate mass and a shift in the geometric mean diameter towards diminished values, thereby signifying enhanced combustion and decreased soot production. The categorisation of particles into nucleation and accumulation modes demonstrated a concentration-dependent behaviour, wherein lower concentrations of HHO facilitated the formation of ultrafine particles, while higher concentrations of HHO favoured oxidation processes and particle aggregation. The combustion efficiency, as determined from the concentrations of carbon monoxide and carbon dioxide, exhibited a significant increase with the addition of HHO, reaching a maximum of 96.24% at a concentration of 1% HHO. These results substantiate the hypothesis that HHO enrichment fosters cleaner combustion and presents a viable strategy for mitigating particulate matter emissions in GDI engines without necessitating substantial modifications.