Method For Determining The Valve Opening Moment In Piezo Servo-Driven Injectors

Patent metadata

Field	Value
Publication number	US-2016298562-A1
Application number	US-201415038563-A
Country	US
Kind code	A1
Filing date	Sep 30, 2014
Priority date	Nov 21, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

Where F=force acting on the piezo actuator, E=electrical parameter of the piezo actuator; determining a new scaling factor from the solution of the equation; calculating the difference (U×C−Q) and determining a maximum of said value; and using the instant at which said maximum occurs as valve opening instant.

First claim

What is claimed is:

1 . A method for determining the valve opening instant in piezo servo-driven injectors, the method comprising the following steps:
measuring a voltage U and a charge Q at an end of a charging process of the piezo actuator; determining a provisional scaling factor C VORL by calculating Q/U; determining the curve maximum of C VORL with respect to time and using the instant at which the maximum occurs as an approximation value of the valve opening instant; measuring the charge Q and voltage U at the instant of the determined approximation value of the valve opening instant; solving the equation
1.25× F 2 /E×C =( U×C−Q ) 2

(F=force acting on the piezo actuator, E=electrical parameter of the piezo actuator);
determining a new scaling factor C from the solution of the equation; calculating the difference (U×C−Q) and determining a maximum of said value; and using the instant at which said maximum occurs as valve opening instant.

2 . The method as claimed in claim 1 , wherein the factor 1.25×F 2 /E is obtained from the rail pressure measurement.

3 . The method as claimed in claim 1 , wherein the provisional scaling factor C VORL is determined in a preceding injection cycle N and is used in a subsequent injection cycle N+1 for the determination of the valve opening instant.

4 . The method as claimed in claim 1 , further comprising:
calculating the idle travel based at least in part on the valve opening instant; and adjusting an injection quantity of the injectors based on the calculated idle travel.

5 . A method for controlling the injection of fuel into a combustion chamber of an internal combustion engine, the method comprising:
measuring a voltage U and a charge Q at the end of a charging process of a piezo actuator associated with the combustion chamber; determining a provisional scaling factor C VORL by calculating Q/U; determining a curve maximum of C VORL with respect to time and using an instant at which the maximum occurs as an approximation value of the valve opening instant; measuring the charge Q and voltage U at the instant of the determined approximation value of the valve opening instant; solving the equation
1.25× F 2 /E×C =( U×C−Q ) 2

(F=force acting on the piezo actuator, E=electrical parameter of the piezo actuator);
determining a new scaling factor C from the solution of the equation; calculating the difference (U×C−Q) and determining a maximum of said value; using the instant at which said maximum occurs as valve opening instant; calculating the idle travel based at least in part on the valve opening instant; and adjusting a control signal of the injector based on the calculated idle travel.

Assignees

• Continental Automotive Gmbh

Inventors

• Dian Vincent

Classifications

• F02M51/0603

  using piezoelectric or magnetostrictive operating means · CPC title

• F02D2200/0618

  Actual fuel injection timing or delay, e.g. determined from fuel pressure drop · CPC title

• F02M63/0026

  using piezoelectric or magnetostrictive actuators · CPC title

• F02D41/2096 Primary

  for controlling piezoelectric injectors (drive and control circuit for piezoelectric devices in general H10N30/802) · CPC title

• F02D41/2467

  for injectors · CPC title