en موتور احتراق داخلی Internal Combustion Engines (ICE, ...) پژوهشي Research <span style="font-size:10pt"><span new="" roman="" style="font-family:" times="">This study investigates the effects of ozone gas injection on reducing exhaust emissions in internal combustion engines (ICEs). Ozone (O₃), a highly reactive oxidizing agent, has been widely utilized for air and water purification. Its ability to break down pollutants makes it a promising alternative or supplement to conventional catalytic converters, which require expensive materials and periodic recycling. In this research, ozone gas was generated using the corona discharge method and injected into the combustion system to evaluate its impact on carbon monoxide (CO) emissions. A low-power 12-volt compressor, capable of producing up to 10 bar pressure, was used to ensure proper injection. A five-gas analyzer was employed to measure emission changes before and after ozone injection. Results indicated an average CO reduction of 34&ndash;40% across seven tested vehicles, with the highest effectiveness observed at steady-state engine operation and moderate loads. Furthermore, an increase in lambda (&lambda;) values suggested improved air-fuel combustion efficiency. Statistical analysis, including standard deviation (&plusmn;0.005) and a 95% confidence interval, confirmed the reliability of these findings. The results demonstrate that ozone injection can serve as a cost-effective method to supplement traditional emission control technologies, potentially reducing reliance on catalytic converters.</span></span><br> &nbsp; Co Emission, Reduction of greenhouse gas emission, ozone injection, internal combustion engines, catalyst supplement 4646 4653 http://ase.iust.ac.ir/browse.php?a_code=A-10-801-1&slc_lang=en&sid=1 Alireza Goharian 180031947532846004803 180031947532846004803 No Automotive Engineering Group, Technical and Vocational Training Organization, Alborz, Iran. Alireza Asadolahei alireza4573@gmail.com 180031947532846004804 180031947532846004804 Yes Mechanical Engineering Group, Faculty of Engineering, Imam Khomeini International University, Qazvin, Iran