FUEL-CETANE-NUMBER ESTIMATION METHOD AND APPARATUS

摘要

An object is to provide a method and an apparatus which can be implemented with a simplified and inexpensive configuration without causing a misfire in a combustion state. In a fuel-Cetane-number estimation method of the present invention, a map which specifies a relationship between the Cetane number and a control parameter at which NOx concentration of exhaust gas reaches a predetermined value is prepared in advance. Then, the control parameter is controlled variably to detect transition of the NOx concentration of the exhaust gas of the internal combustion engine, and thereby the control parameter of the internal combustion engine at which the NOx concentration has reached the predetermined value is obtained, and the Cetane number which corresponds to the obtained control parameter is estimated on the basis of the map.

主权项

1. A fuel-Cetane-number estimation method of estimating a Cetane number of a fuel used in an internal combustion engine which performs compression ignition combustion, comprising:
preparing in advance a map which specifies a relationship between the Cetane number of the fuel and a control parameter of the internal combustion engine at which NOx concentration of exhaust gas of the internal combustion engine reaches a predetermined concentration value; controlling the control parameter of the internal combustion engine variably to detect transition of the NOx concentration of the exhaust gas of the internal combustion engine; obtaining the control parameter of the internal combustion engine at which the NOx concentration has reached the predetermined concentration value on the basis of the detected NOx concentration; and estimating the Cetane number which corresponds to the obtained control parameter on the basis of the map.