Fuel-cetane-number estimation method and apparatus

Patent metadata

Field	Value
Publication number	US-2016010580-A1
Application number	US-201314764125-A
Country	US
Kind code	A1
Filing date	Dec 11, 2013
Priority date	Feb 22, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

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.

First claim

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.

2 . The fuel-Cetane-number estimation method according to claim 1 , further comprising:
detecting a state factor which affects the NOx concentration of the exhaust gas of the internal combustion engine; and correcting the map by using a predetermined correction value which corresponds to the detected state factor.

3 . The fuel-Cetane-number estimation method according to claim 1 , further comprising:
detecting a state factor which affects the NOx concentration of the exhaust gas of the internal combustion engine; and correcting the predetermined concentration value by using a predetermined correction value which corresponds to the detected state factor.

4 . The fuel-Cetane-number estimation method according to claim 2 or 3 ,
wherein the state factor includes at least one of a temperature of a coolant water, a temperature of an inlet of a cylinder, a pressure of the inlet of the cylinder, oxygen concentration of the cylinder, an amount of intake air, a pressure of the intake air, or a humidity of the intake air of the internal combustion engine.

5 . The fuel-Cetane-number estimation method according to any one of claims 1 to 4 ,
wherein execution of the fuel-Cetane-number estimation method is automatically started if a predetermined starting condition is satisfied.

6 . The fuel-Cetane-number estimation method according to any one of claims 1 to 5 ,
wherein the control parameter is an amount of retard in a fuel injection timing in a combustion chamber of the internal combustion engine.

7 . The fuel-Cetane-number estimation method according to any one of claims 1 to 5 ,
wherein the control parameter is an amount of recirculation of the exhaust gas to the intake air of the internal combustion engine.

8 . A fuel-Cetane-number estimation apparatus for estimating a Cetane number of a fuel used in an internal combustion engine which performs compression ignition combustion, comprising:
a NOx concentration detection unit for detecting NOx concentration of exhaust gas of the internal combustion engine; an internal-combustion-engine control unit for variably controlling a control parameter of the internal combustion engine; a storage unit for storing a map which specifies a relationship between the Cetane number of the fuel and the control parameter of the internal combustion engine at which the NOx concentration of the exhaust gas of the internal combustion engine reaches a predetermined concentration value; and a Cetane-number estimation unit for variably controlling the control parameter with the internal-combustion-engine control unit to vary the NOx concentration of the exhaust gas of the internal combustion engine, obtaining the control parameter at which the NOx concentration reaches the predetermined concentration value, and estimating the Cetane number which corresponds to the obtained control parameter on the basis of the map.

9 . The fuel-Cetane-number estimation apparatus according to claim 8 , further comprising:
a state-factor detection unit for detecting a state factor which affects the NOx concentration of the exhaust gas of the internal combustion engine; and a correction unit for correcting the map by using a predetermined correction value which corresponds to the state factor detected by the state-factor detection unit.

10 . The fuel-Cetane-number estimation apparatus according to claim 8 , further comprising:
a state-factor detection unit for detecting a state factor which affects the NOx concentration of the exhaust gas of the internal combustion engine; and a correction unit for correcting the predetermined concentration value by using a predetermined correction value which corresponds to the state factor detected by the state-factor detection unit.

11 . The fuel-Cetane-number estimation apparatus according to any one of claims 8 to 10 ,
wherein the NOx concentration detection unit is also used as a NOx sensor used to calculate a purification rate in an exhaust-gas purification device for purifying the exhaust gas of the internal combustion engine.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Yamamoto Takayuki

Classifications

• F02D41/1461 Primary

  of the exhaust gases emitted by the engine · CPC title

• G01N33/0037

  NOx · CPC title

• F02D41/0072

  Estimating, calculating or determining the EGR rate, amount or flow (sensors in EGR systems F02M26/45) · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• G01N33/22

  Fuels; Explosives · CPC title