Car Craze

A significant portion of a vehicle’s emission occurs immediately after start-up when the catalytic converter is not yet warmed up to its proper operating temperature. A new software that is used to control the start-up sequence and minimize engine-out emissions during this period seeks to address this problem. This is otherwise known as variable valve timing or VVT which is the computerized control of the engine’s intake and exhaust valves to manage emissions during the vehicle’s cold start routine.

In the process, the opening of the intake valve is delayed thereby improving the air/fuel mixture which enhances stability during combustion. When the combustion process is run very late, fuel is burned up on the cylinder wall and reduces HC and NOx emissions. As the exhaust valve opening is delayed, the hydrocarbon-rich exhaust gas residual is brought back into the cylinder which further reduces HC emissions.