Compressed Natural Gas (CNG) offers a compelling alternative fuel solution due to its lower carbon emissions and cost-effectiveness compared to conventional gasoline. However, the dry combustion characteristics of CNG, coupled with higher combustion temperatures, often accelerate Exhaust valve face and Exhaust seat insert wear in internal combustion engines. Intake valve face and Intake seat insert are exposed to fresh air charge and temperature during engine operation remain with in limit and no issue reported in Intake valve side.
This study addresses the critical challenge of premature exhaust valve wear in CNG applications by investigating the root cause and implementing improvements in the exhaust valve facing material, aiming to enhance durability and reliability for widespread CNG vehicle adoption.
Exhaust valve face in CNG engine subjected to extreme condition leads to excessive valve face wear and cracking. To address these challenges, various technologies like hard material deposition, hardening processes, and Diamond-Like Carbon (DLC) coatings have been developed for valve face wear resistance improvement. Most common solution adapted by different OEM are using Hard facing material to resist wear and crack. Hard facing material is deposited by welding process which itself is overly critical and need precise control to achieve desired part quality.
Our development focused on identifying key process-controlled parameters for preventing valve seat wear in Exhaust Valve by optimizing hard facing material deposition process parameters, hard facing material microstructure, residual stress, blowholes, and hardness.