Flow measurement of re-circulated gas in an internal combustion engine using a computer to calculate the flow from pressure and temperature measurements using a fixed orifice to control gas flow

摘要

A computer calculates the gas flow based on pressure measurement made using a fixed orifice in the exhaust re-circulation system. Correction is applied for temperature and may also be applied for engine airflow and barometric pressure. The pressure downstream of a fixed orifice (205) located downstream of a flow control valve (200) is measured. The pressure difference across the orifice is also measured.