US 8,469,010 B2 · Control device for internal combustion engine and measuring device of mass flow rate of NOx recirculated to intake passage with blowby gas

Abstract

A mass flow rate of NOx which is recirculated to an intake passage with a blowby gas is obtained with high precision, and based on the result, a state of an internal combustion engine can be accurately diagnosed. A control device for an internal combustion engine of the present invention measures a NOx concentration in an intake passage downstream from a position where the blowby gas is recirculated, and similarly measures an oxygen concentration in the intake passage downstream from the aforesaid position. Further, the control device measures a mass flow rate of fresh air taken into the intake passage. The control device calculates a mass flow rate of the blowby gas recirculated to the intake passage from the oxygen concentration and the mass flow rate of the fresh air. Next, the control device calculates a mass flow rate of all gases in the intake passage from the mass flow rate of the fresh air and the mass flow rate of the blowby gas. Subsequently, the control device calculates the mass flow rate of NOx in the aforesaid intake passage from the mass flow rate of all the gases and the NOx concentration. The present control device diagnoses the state of the internal combustion engine based on the mass flow rate of NOx thus calculated.

Claims9

Dependent claims

A measuring device that is a device for measuring a mass flow rate of NOx recirculated to an intake passage with a blowby gas in an internal combustion engine in which the blowby gas is recirculated to the intake passage, comprising:

a NOx sensor attached to a downstream side from a position where the blowby gas is recirculated in said intake passage;
an air flowmeter attached to an inlet port of said intake passage;
and
a signal processing device that processes each of signals from said NOx sensor and air flowmeter,
wherein said signal processing device includes:
a NOx concentration measuring unit that converts a signal from said NOx sensor into a NOx concentration;
an oxygen concentration measuring unit that converts the signal from said NOx sensor into an oxygen concentration;
a fresh air mass flow rate measuring unit that converts a signal from said air flowmeter into a mass flow rate of fresh air;
a blowby gas mass flow rate calculating unit that calculates a mass flow rate of the blowby gas recirculated to said intake passage from the oxygen concentration and the mass flow rate of the fresh air;
an all gas mass flow rate calculating unit that calculates a mass flow rate of all gases in said intake passage from the mass flow rate of the fresh air and the mass flow rate of the blowby gas;
and
a NOx mass flow rate calculating unit that calculates a mass flow rate of NOx in said intake passage from the mass flow rate of all the gases and the NOx concentration.

9 more elements

A control device for an internal combustion engine in which a blowby gas is recirculated to an intake passage, comprising:

NOx concentration measuring means that measures a NOx concentration in said intake passage downstream from a position where the blowby gas is recirculated;
oxygen concentration measuring means that measures an oxygen concentration in said intake passage downstream from the position where the blowby gas is recirculated;
fresh air mass flow rate measuring means that measures a mass flow rate of fresh air taken into said intake passage;
blowby gas mass flow rate calculating means that calculates a mass flow rate of the blowby gas recirculated to said intake passage from the oxygen concentration and the mass flow rate of the fresh air;
all gas mass flow rate measuring means that measures a mass flow rate of all gases in said intake passage from the mass flow rate of the fresh air and the mass flow rate of the blowby gas;
NOx mass flow rate calculating means that calculates a mass flow rate of NOx in said intake passage from the mass flow rate of all the gases and the NOx concentration;
and
diagnosis means that diagnoses a state of said internal combustion engine based on the mass flow rate of NOx.

5 more elements

Dependencies are inferred from the claim text.

Control device for internal combustion engine and measuring device of mass flow rate of NOx recirculated to intake passage with blowby gas

Life of this patent

Control device for internal combustion engine and measuring device of mass flow rate of NOx recirculated to intake passage with blowby gas

Life of this patent

Abstract

Claims9