EGR apparatus of engine

Patent metadata

Field	Value
Publication number	US-RE50153-E
Application number	US-202217723038-A
Country	US
Kind code	E1
Filing date	Apr 18, 2022
Priority date	Oct 5, 2017
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

An EGR apparatus includes an EGR passage to allow part of exhaust gas discharged from an engine to an exhaust passage to flow as EGR gas into an intake passage; an EGR valve to regulate an EGR flow rate in the EGR passage; various sensors for detecting an engine running state; and an ECU to control the EGR valve based on the detected running state to diagnose abnormality in the EGR valve. The ECU calculates a reference intake pressure according the detected engine rotation speed and load by reference to a reference intake pressure map showing a relationship of the reference intake pressure to engine rotation speed, and engine load, and determine whether or not the EGR valve has abnormality in opening/closing by comparing the reference intake pressure with the detected intake pressure.

First claim

What is claimed is:

1. An EGR apparatus of an engine, the EGR apparatus comprising:
an EGR passage configured to allow part of exhaust gas discharged from the engine to an exhaust passage to flow as EGR gas from the exhaust passage to an intake passage in order to recirculate the EGR gas into the engine;
an EGR valve configured to regulate a flow rate of the EGR gas in the EGR passage, the EGR valve including a valve seat, a valve element provided to be seatable on the valve seat, and an actuator to move the valve element;
a running-state detecting unit configured to detect a running state of the engine;
an EGR valve control unit configured to control the EGR valve based on the detected running state; and
an EGR valve abnormality diagnosing unit configured to diagnose an abnormality in opening/closing between the valve seat and the valve element of the EGR valve based on the detected running state, wherein
the running-state detecting unit includes:
an intake pressure detecting unit configured to detect intake pressure in the intake passage downstream of a position where the EGR gas flows from the EGR passage into the intake passage;
a rotation speed detecting unit configured to detect a rotation speed of the engine; and
a load detecting unit configured to detect a load of the engine,

the EGR valve abnormality diagnosing unit is configured to determine whether or not the EGR valve has the abnormality by comparing a reference intake pressure calculated based on the detected rotation speed and the detected load with the detected intake pressure or by comparing a reference opening degree of the EGR valve calculated based on the detected rotation speed, the detected load, and the detected intake pressure with a control opening degree of the EGR valve under control by the EGR valve control unit,
the EGR valve abnormality diagnosing unit is provided with a reference function map or a reference function expression previously set to show a relationship of the reference intake pressure to the rotation speed and the load, and
the EGR valve abnormality diagnosing unit is configured to calculate the reference intake pressure according to the detected rotation speed and the detected load by reference to the reference function map or the reference function expression, and determine whether or not the EGR valve has the abnormality by comparing the calculated reference intake pressure with the detected intake pressure,
when the engine is in deceleration and the EGR valve control unit the EGR valve to close to a valve-closed state, and
the EGR valve abnormality diagnosing unit is configured to determine whether or not the EGR valve has the abnormality by comparing a decrease rate of the detected intake pressure with a predetermined decrease rate.

2. An EGR apparatus of an engine, the EGR apparatus comprising:
an EGR passage configured to allow part of exhaust gas discharged from the engine to an exhaust passage to flow as EGR gas from the exhaust passage to an intake passage in order to recirculate the EGR gas into the engine;
an EGR valve configured to regulate a flow rate of the EGR gas in the EGR passage,
the EGR valve including a valve seat, a valve element provided to be seatable on the valve seat, and an actuator to move the valve element;
a running-state detecting unit configured to detect a running state of the engine;
an EGR valve control unit configured to control the EGR valve based on the detected running state; and
an EGR valve abnormality diagnosing unit configured to diagnose an abnormality in opening/closing between the valve seat and the valve element of the EGR valve based on the detected running state, wherein
the running-state detecting unit includes:
an intake pressure detecting unit configured to detect intake pressure in the intake passage downstream of a position where the EGR gas flows from the EGR passage into the intake passage;
a rotation speed detecting unit configured to detect a rotation speed of the engine; and
a load detecting unit configured to detect a load of the engine,

the EGR valve abnormality diagnosing unit is configured to determine whether or not the EGR valve has the abnormality by comparing a reference intake pressure calculated based on the detected rotation speed and the detected load with the detected intake pressure or by comparing a reference opening degree of the EGR valve calculated based on the detected rotation speed, the detected load, and the detected intake pressure with a control opening degree of the EGR valve under control by the EGR valve control unit,
the EGR valve abnormality diagnosing unit is provided with a reference function map or a reference function expression previously set to show a relationship of the reference intake pressure to the rotation speed and the load, and
the EGR valve abnormality diagnosing unit is configured to calculate the reference intake pressure according to the detected rotation speed and the detected load by reference to the reference function map or the reference function expression, and determine whether or not the EGR valve has the abnormality by comparing the calculated reference intake pressure with the detected intake pressure,
the EGR apparatus further includes a foreign-matter removal control unit, and
when it is determined that the EGR valve has the abnormality, the foreign-matter removal control unit is configured to:
obtain an opening degree corresponding to a diameter of a foreign matter lodged between the valve seat and the valve element based on a foreign-matter diameter equivalent ratio obtained by dividing the detected intake pressure by the calculated reference intake pressure; and
execute a foreign-matter removal control that controls the actuator to open the valve element at a larger opening degree than the obtained opening degree corresponding to the diameter of the foreign matter to remove the foreign matter from between the valve seat and the valve element.

3. An EGR apparatus of an engine, the EGR apparatus comprising:
an EGR passage configured to allow part of exhaust gas discharged from the engine to an exhaust passage to flow as EGR gas from the exhaust passage to an intake passage in order to recirculate the EGR gas into the engine;
an EGR valve configured to regulate a flow rate of the EGR gas in the EGR passage,
the EGR valve including a valve seat, a valve element provided to be seatable on the valve seat, and an actuator to move the valve element;
a running-state detecting unit configured to detect a running state of the engine;
an EGR valve control unit configured to control the EGR valve based on the detected running state; and
an EGR valve abnormality diagnosing unit configured to diagnose an abnormality in opening/closing between the valve seat and the valve element of the EGR valve based on the detected running state, wherein
the running-state detecting unit includes:
an intake pressure detecting unit configured to detect intake pressure in the intake passage downstream of a position where the EGR gas flows from the EGR passage into the intake passage;
a rotation speed detecting unit configured to detect a rotation speed of the engine; and
a load detecting unit configured to detect a load of the engine, and

the EGR valve abnormality diagnosing unit is configured to determine whether or not the EGR valve has the abnormality by comparing a reference intake pressure calculated based on the detected rotation speed and the detected load with the detected intake pressure or by comparing a reference opening degree of the EGR valve calculated based on the detected rotation speed, the detected load, and the detected intake pressure with a control opening degree of the EGR valve under control by the EGR valve control unit,
the EGR valve abnormality diagnosing unit is provided with a reference function map o

Assignees

• Aisan Ind

Inventors

• Yoshioka Mamoru

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02D41/221

  relating to the failure of actuators or electrically driven elements · CPC title

• F02D2200/1002

  Output torque · CPC title

• F02D2200/0408

  Estimation of intake manifold pressure · CPC title

• F02D2200/101

  Engine speed · CPC title