FUEL INJECTION CONTROLLER

• US 20140288805A1
• Filed: 03/14/2014
• Published: 09/25/2014
• Est. Priority Date: 03/22/2013
• Status: Active Grant

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: FUJIME, Yoko
• Granted Patent: US 9,745,913 B2
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/2454 Learning of the air-fuel ratio control
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for

Abstract

A fuel injection controller includes an oxygen sensor that responds to an oxygen concentration inside an exhaust passage, and an injection amount control unit programmed to control a fuel injection amount based on the output of the oxygen sensor. The injection amount control unit includes an injection amount correction value computing unit that determines an injection amount correction value based on the output of the oxygen sensor, a short-time learning value computing unit that determines a short-time learning value based on the injection amount correction value, a long-time learning value computing unit that determines a long-time learning value based on the short-time learning value; a feedback correction amount computing unit that computes a feedback correction amount, an injection amount control value computing unit that computes a control value of the fuel injection amount, and a long-time learning value holding unit that holds the long-time learning value.

Claims

1. A fuel injection controller for controlling a fuel injection amount of a fuel injector in an engine of a vehicle, the fuel injection controller comprising:

an oxygen sensor that responds to an oxygen concentration inside an exhaust passage through which an exhaust of the engine passes; and

an injection amount control unit programmed to control the fuel injection amount based on an output of the oxygen sensor, wherein the injection amount control unit includes;

an injection amount correction value computing unit that determines an injection amount correction value based on the output of the oxygen sensor;

a short-time learning value computing unit that determines, based on the injection amount correction value, a short-time learning value that is updated at a predetermined short-time learning speed;

a long-time learning value computing unit that determines, based on the short-time learning value, a long-time learning value that is updated at a long-time learning speed that is slower than the short-time learning speed;

a feedback correction amount computing unit that computes a feedback correction amount based on a sum of the injection amount correction value, the short-time learning value, and the long-time learning value;

an injection amount control value computing unit that computes a control value of the fuel injection amount using the feedback correction amount; and

a long-time learning value holding unit that stores the long-time learning value;

wherein

when the engine is started, the long-time learning value computing unit reads and uses a previous long-time learning value from the long-time learning value holding unit while the short-time learning value computing unit starts computing the short-time learning value anew without inheriting a previous short-time learning value.

2. The fuel injection controller according to claim 1, wherein the short-time learning value computing unit updates the short-time learning value so that the injection amount correction value approaches zero, and the long-time learning value computing unit updates the long-time learning value such that the short-time learning value approaches zero.

3. The fuel injection controller according to claim 1, wherein the injection amount control unit includes a feedback control interrupting unit that interrupts the determining by the injection amount correction value computing unit when a predetermined interruption condition is established to interrupt the feedback control based on the output of the oxygen sensor;

the short-time learning value computing unit stores the short-time learning value for a predetermined hold time when the feedback control is interrupted and, when a time during which the feedback control is interrupted reaches the predetermined hold time, makes the short-time learning value approach zero gradually; and

the feedback correction amount computing unit computes a sum of the short-time learning value and the long-time learning value as the feedback correction amount when the feedback control is interrupted.

4. The fuel injection controller according to claim 3, wherein the feedback control interrupting unit interrupts the feedback control when an air induction operation of introducing air into the exhaust passage is being performed and when a fuel cut control of setting the fuel injection amount to zero is being performed.

5. The fuel injection controller according to claim 1, wherein, when an absolute value of the injection amount correction value is greater than a predetermined high-speed learning threshold, the short-time learning value computing unit updates the short-time learning value at a high-speed short-time learning speed that is faster than the short-time learning speed.

6. The fuel injection controller according to claim 1, further comprising an abnormality judging unit that compares an absolute value of a sum of the short-time learning value and the long-time learning value with a predetermined abnormality threshold to judge whether or not there is an abnormality in a fuel supply system of the engine.

7. The fuel injection controller according to claim 1, further comprising:

an idling stop unit that automatically stops the engine when a predetermined idling stop condition is met; and

a restart unit that restarts the engine when a predetermined restart condition is met in an automatic stop state in which the engine is automatically stopped by the idling stop unit;

wherein

when the engine is restarted by the restart unit, the short-time learning value computing unit inherits the previous short-time learning value.