CONTROLLER OF INTERNAL COMBUSTION ENGINE, AND DEVICE FOR MEASURING MASS FLOW OF NOx REFLUXED BACK TO INTAKE PASSAGE ALONG WITH BLOW-BY GAS

摘要

Disclosed is a device for measuring the mass flow of NOx which is refluxed to the intake passage along with blow-by gas with high precision, so that the state of an internal combustion engine can be diagnosed accurately based on the measurement results. The controller of an internal combustion engine measures the concentration of NOx in the intake passage in the downstream of a position where the blow-by gas is refluxed, and measures the concentration of oxygen in the intake passage in the downstream of the above-mentioned position. Mass flow of fresh air which is taken into the intake passage is also measured. Mass flow of blow-by gas which is refluxed to the intake passage is then calculated from the concentration of oxygen and the mass flow of fresh air. Thereafter, the mass flow of all gas in the intake passage is calculated from the mass flow of fresh air and the mass flow of blow-by gas. Finally, the mass flow of NOx in the intake passage is calculated from the mass flow of all gas and the concentration of NOx. The controller diagnoses the state of the internal combustion engine based on the mass flow of NOx thus calculated.