Secondary air supply system and abnormality diagnosis method of secondary air supply system
First Claim
1. A secondary air supply system that supplies secondary air to each of exhaust pipes attached to each of two banks of an internal combustion engine via a secondary air supply pipe including a joint portion and two branch portions divided from the joint portion, the secondary air supply system comprising two air control valves respectively provided in the two branch portions, and a pressure sensor provided in the joint portion of the secondary air supply pipe, wherein an abnormality diagnosis is executed with respect to the two air control valves which are opened at different timings, the two air control valves including a first air control valve that is firstly opened and a second air control valve that is secondly opened, based on a combination of a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the first air control valves and a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the second air control valve.
1 Assignment
0 Petitions
Accused Products
Abstract
In a secondary air supply system, each of two branch portions of a secondary air supply pipe that is divided from a joint portion is provided with an air control valve, and the joint portion is provided with a pressure sensor and an auxiliary air control valve. The air control valves are opened at different timings such that pressure fluctuations in the joint portion upon opening of the firstly and the secondly opened air control valves are measured. An abnormality diagnosis is performed with respect to those two air control valves based on combinations of the aforementioned two pressure fluctuations.
-
Citations
24 Claims
- 1. A secondary air supply system that supplies secondary air to each of exhaust pipes attached to each of two banks of an internal combustion engine via a secondary air supply pipe including a joint portion and two branch portions divided from the joint portion, the secondary air supply system comprising two air control valves respectively provided in the two branch portions, and a pressure sensor provided in the joint portion of the secondary air supply pipe, wherein an abnormality diagnosis is executed with respect to the two air control valves which are opened at different timings, the two air control valves including a first air control valve that is firstly opened and a second air control valve that is secondly opened, based on a combination of a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the first air control valves and a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the second air control valve.
- 14. An abnormality diagnosis method of a secondary air supply system that supplies secondary air to each of exhaust pipes attached to each of two banks of an internal combustion engine via a secondary air supply pipe including a joint portion and two branch portions divided from the joint portion, the secondary air supply system further including two air control valves respectively provided in the two branch portions, and a pressure sensor provided in the joint portion of the secondary air supply pipe, wherein an abnormality diagnosis is executed with respect to the two air control valves which are opened at different timings, the two air control valves including a first air control valve that is firstly opened and a second air control valve that is secondly opened, based on a combination of a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the first air control valves and a fluctuation of a pressure in the joint portion detected by the pressure sensor upon opening of the second air control valve.
Specification