Pressure sensor of a high-pressure injection system, control device, high-pressure injection system, and motor vehicle

Patent metadata

Field	Value
Publication number	US-10731591-B2
Application number	US-201716340225-A
Country	US
Kind code	B2
Filing date	Jun 7, 2017
Priority date	Oct 13, 2016
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

Various embodiments include a method comprising: moving a piston toward TDC in successive pump cycles; during the movement, closing an inlet valve by applying current to an electromagnet; generating a pressure signal downstream of the outlet; applying a measurement current to the electromagnet when the inlet valve is closed; while the piston moves away from TDC, detecting an opening position at which an opening movement of the inlet valve begins on the basis of a predetermined change with respect to time of the measurement current; checking whether a value sequence of the ascertained opening positions over multiple pump cycles satisfies a predetermined discrepancy criterion with regard to the sensor signal; and if the discrepancy criterion is satisfied, generating a fault signal relating to the pressure sensor.

First claim

What is claimed is:

1. A method for checking a pressure sensor of a high-pressure injection system of an internal combustion engine of a motor vehicle, the method comprising:
moving a piston toward a top dead center within a compression chamber of a high-pressure pump in successive pump cycles during an expulsion phase, expelling a fluid from the compression chamber;
during movement of the piston toward top dead center, closing an inlet valve using a control device by applying current to an electromagnet, wherein the expelled fluid generates a fluid pressure downstream of the outlet valve in a high-pressure region;
generating a pressure signal using the pressure sensor arranged downstream of the outlet valve;
applying a measurement current to the electromagnet using the control device when the inlet valve is closed;
while the piston moves away from top dead center, detecting an opening position of the piston at which an opening movement of the inlet valve begins on the basis of a predetermined change with respect to time of the measurement current;
checking whether a value sequence of the ascertained opening positions over multiple pump cycles satisfies a predetermined discrepancy criterion with regard to the sensor signal; and
if the discrepancy criterion is satisfied, generating a fault signal relating to the pressure sensor.

2. The method as claimed in claim 1 , wherein the discrepancy criterion corresponds to an indication based on the value sequence that the opening position shifts away from the top dead center and thus a rising pressure profile of the fluid pressure and the sensor signal of the pressure sensor deviates from the pressure profile by more than a predetermined tolerance value.

3. The method as claimed in claim 1 , further comprising indicating a delta step change with the control device if a difference of the sensor signal relative to the value sequence of greater than a predetermined delta value is identified on the basis of a difference signal.

4. The method as claimed in claim 3 , further comprising counting with the control device how often a delta step change is identified in succession; and
wherein the discrepancy criterion comprises a count greater than a predetermined minimum number.

5. The method as claimed in claim 1 , wherein the discrepancy criterion indicates a rotational speed of an engine shaft driving the piston greater than a predetermined operating value.

6. The method as claimed in claim 1 , wherein the discrepancy criterion indicates a volume flow of the fluid greater than a predetermined minimum delivery value.

7. The method as claimed in claim 1 , further comprising ascertaining the value sequence and checking the discrepancy criterion if, upon a start of the internal combustion engine, the sensor signal has a constant profile in accordance with a predetermined constancy criterion.

8. The method as claimed in claim 1 , further comprising setting a current intensity of the measurement current lower than is provided for the closing of the inlet valve.

9. The method as claimed in claim 1 , wherein the predetermined change with respect to time of the measurement current for the detection of the opening movement indicates a predetermined mean value of the measurement current increases.

10. The method as claimed in claim 1 , wherein ascertaining the opening position includes monitoring a rotational position sensor of the internal combustion engine.

11. A control device for a high-pressure injection system of an internal combustion engine of a motor vehicle, the control device comprising:
a processor; and
a memory storing a set of instructions, the set of the instructions, when loaded and executed by the processor, causing the processor to:
close an inlet valve of a high-pressure pump of the high-pressure injection system in a manner dependent on a sensor signal of a pressure sensor;
move a piston toward a top dead center within a compression chamber of a high-pressure pump in successive pump cycles during an expulsion phase, expelling a fluid from the compression chamber;
during movement of the piston toward top dead center, close an inlet valve using a control device by applying current to an electromagnet, wherein the expelled fluid generates a fluid pressure downstream of the outlet valve in a high-pressure region;
generate a pressure signal using the pressure sensor arranged downstream of the outlet valve;
apply a measurement current to the electromagnet using the control device when the inlet valve is closed;
while the piston moves away from top dead center, detect an opening position of the piston at which an opening movement of the inlet valve begins on the basis of a predetermined change with respect to time of the measurement current;
check whether a value sequence of the ascertained opening positions over multiple pump cycles satisfies a predetermined discrepancy criterion with regard to the sensor signal; and
if the discrepancy criterion is satisfied, generate a fault signal relating to the pressure sensor.

Assignees

• Cpt Group Gmbh
• Vitesco Tech Gmbh

Inventors

• Chia Tet Kong Brian
• Kogan Dmitriy

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D2041/223

  Diagnosis of fuel pressure sensors · CPC title

• F02D2041/2055

  with means for determining actual opening or closing time · CPC title

• F02D41/222

  relating to the failure of sensors or parameter detection devices · CPC title