Fuel-injection-characteristics learning apparatus

Patent metadata

Field	Value
Publication number	US-9127612-B2
Application number	US-201113325531-A
Country	US
Kind code	B2
Filing date	Dec 14, 2011
Priority date	Dec 15, 2010
Publication date	Sep 8, 2015
Grant date	Sep 8, 2015

Abstract

A characteristics-detecting-portion analyzes a fuel injection condition based on a fuel pressure waveform which represents a variation in a detection value of the fuel pressure sensor and then detects the fuel-injection-characteristic value based on the analyzed fuel injection condition. The detected parameter is learned and stored in a memory in association with a fuel temperature detected by a fuel temperature sensor. A fuel-injection-rate model is established based on the learned detected parameters. A command-fuel-injection start time and a command-fuel-injection period are defined by use of the fuel-injection-rate model and the current fuel temperature.

First claim

What is claimed is:

1. A system comprising:
a fuel injector for injecting the high-pressure fuel accumulated in a accumulator through a fuel injection port;
a memory for storing a fuel-injection-characteristic value which the fuel injector individually has;
a fuel pressure sensor provided in a fuel passage fluidly connecting the accumulator and the fuel injection port, the fuel pressure sensor being configured to detect a fuel pressure in the fuel passage;
a fuel temperature sensor for detecting a fuel temperature;
an electronic control unit (ECU) configured to:
generate a fuel-injection command signal based on the fuel-injection-characteristic value;
analyze a fuel injection condition based on a fuel pressure waveform which represents a variation in a detection value of the fuel pressure sensor, the fuel-injection-characteristic value being detected based on the analyzed fuel injection condition;
store the fuel-injection-characteristic value in the memory in association with the fuel temperature detected by the fuel temperature sensor; wherein

the memory stores a characteristics formula representing a relationship between the fuel-injection characteristic value and the fuel temperature;
the electronic control unit is further configured to update the characteristics formula based on the detected fuel-injection-characteristic value;
when a difference between the detected fuel-injection-characteristic value and an unlearned fuel-injection-characteristic value stored in the memory is less than a specified value, the electronic control unit updates the characteristics formula into a characteristics formula which is offset by the difference;
when the difference between the detected fuel-injection-characteristic value and the unlearned fuel-injection-characteristic value stored in the memory is not less than the specified value, the electronic control unit updates the characteristics formula into a characteristics formula of which inclination is varied according to the difference; and
the electronic control unit is further configured to compute the fuel-injection-characteristic value according to the characteristics formula.

2. The system according to claim 1 , wherein:
the electronic control unit is further configured to correct the fuel-injection-characteristic value corresponding to a current fuel temperature into a fuel-injection-characteristic value corresponding to a reference fuel temperature in a case that the current fuel temperature detected by the fuel temperature sensor is outside of a specified temperature range, the reference fuel temperature being within the specified temperature range, wherein
the electronic control unit is further configured to store the corrected fuel-injection-characteristic value in the memory in association with the reference fuel temperature.

3. The system according to claim 1 , wherein
when the fuel temperature detected by the fuel temperature sensor exceeds a specified upper limit value or falls below a specified lower limit value, it is prohibited that the fuel-injection-characteristic value corresponding to the fuel temperature is stored in the memory.

Assignees

• Nakata Kenichiro
• Ishizuka Koji
• Denso Corp

Inventors

• Nakata Kenichiro
• Ishizuka Koji

Classifications

• F02D2200/0602

  Fuel pressure · CPC title

• F02D41/2467 Primary

  for injectors · CPC title

• F02D2200/0606

  Fuel temperature · CPC title

• F02D41/2451

  characterised by what is learned or calibrated · CPC title

• F02D41/2464

  Characteristics of actuators · CPC title