Fuel supply apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9617960-B2
Application number	US-201113988858-A
Country	US
Kind code	B2
Filing date	Dec 7, 2011
Priority date	Dec 8, 2010
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A fuel supply apparatus for an internal combustion engine includes: a feed pump capable of feeding a fuel of the internal combustion engine; a high pressure fuel pump that pressurizes the fuel fed from the feed pump; and a second injector that supplies the pressurized high-pressure fuel to the internal combustion engine selectively. An ECU of the fuel supply apparatus includes: a pulsation width detection unit that detects a pulsation width in a pressure of the fuel fed from the feed pump to the high pressure fuel pump; and a feeding condition determination unit that determines that a condition variation causing fuel vapor to form in the fuel fed to the high pressure fuel pump has occurred when the pulsation width detected by the pulsation width detection unit falls rapidly to a preset threshold variation width.

First claim

The invention claimed is:

1. A fuel supply apparatus for an internal combustion engine, comprising:
a low pressure fuel pump capable of feeding a fuel of the internal combustion engine;
a high pressure fuel pump that pressurizes and discharges the fuel fed from the low pressure fuel pump;
a high pressure fuel injection valve that supplies the fuel pressurized by the high pressure fuel pump to the internal combustion engine selectively; and
a controller configured to (i) detect a pulsation width in a pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump, and (ii) determine that a condition variation causing fuel vapor to form in the fuel fed from the low pressure fuel pump to the high pressure fuel pump has occurred when the pulsation width detected by the controller falls to a preset threshold pulsation width, wherein
a normal pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump is a pressure at which the pulsation width exceeds the threshold pulsation width,
the controller is further configured to increase the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump to a higher pressure than the normal pressure when the controller determines that the condition variation causing fuel vapor to form in the fuel fed from the low pressure fuel pump to the high pressure fuel pump has occurred, and
the controller is further configured to hold the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump at the higher pressure for at least a preset fixed time from a point at which the pulsation width detected by the controller falls to the threshold pulsation width.

2. The fuel supply apparatus for an internal combustion engine according to claim 1 , further comprising:
a high pressure side fuel pressure sensor that detects a pressure of the fuel pressurized by the high pressure fuel pump, wherein
the controller is further configured to control the high pressure fuel pump based on the pressure detected by the high pressure side fuel pressure sensor so that the pressure of the fuel pressurized by the high pressure fuel pump approaches a target pressure, and
the controller is further configured to cancel a high pressure holding condition in which the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump is held at the higher pressure when the pressure detected by the high pressure side fuel pressure sensor reaches a preset target pressure level.

3. The fuel supply apparatus for an internal combustion engine according to claim 1 , further comprising:
a high pressure side fuel pressure sensor that detects a pressure of the fuel pressurized by the high pressure fuel pump, wherein
the controller is further configured to control the high pressure fuel pump based on the pressure detected by the high pressure side fuel pressure sensor so that the pressure of the fuel pressurized by the high pressure fuel pump approaches a target pressure, and
the controller is further configured to cancel a high pressure holding condition in which the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump is held at the higher pressure when a discharge flow rate of the high pressure fuel pump reaches a preset normal flow rate level.

4. The fuel supply apparatus for an internal combustion engine according to claim 2 , wherein the target pressure is set in advance in accordance with an operating condition of the internal combustion engine to a pressure enabling an in-cylinder injection.

5. The fuel supply apparatus for an internal combustion engine according to claim 1 , wherein the controller is further configured to cancel a high pressure holding condition in which the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump is held at the higher pressure, upon establishment of a condition in which the internal combustion engine is operated in a condition where an open period of the high pressure fuel injection valve exceeds a preset threshold injection period.

6. The fuel supply apparatus for an internal combustion engine according to claim 1 , wherein the high pressure fuel injection valve is configured to include a plurality of in-cylinder injection injectors, the number of which corresponds to the number of cylinders in the internal combustion engine, and
the controller is further configured to detect the pulsation width in the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump, upon establishment of a condition in which the plurality of in-cylinder injection injectors are respectively closed while the internal combustion engine is operative.

7. The fuel supply apparatus for an internal combustion engine according to claim 6 , further comprising a low pressure fuel injection valve that supplies the fuel fed from the low pressure fuel pump to the internal combustion engine selectively,
wherein the low pressure fuel injection valve is configured to include a plurality of port injection injectors, the number of which corresponds to the number of cylinders in the internal combustion engine, and
the controller is further configured to detect the pulsation width in the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump, upon establishment of a condition in which the plurality of in-cylinder injection injectors and the plurality of port injection injectors are respectively closed while the internal combustion engine is operative.

8. The fuel supply apparatus for an internal combustion engine according to claim 6 , wherein the condition in which the plurality of in-cylinder injection injectors are respectively closed while the internal combustion engine is operative corresponds to a fuel cut condition in which a fuel supply from the high pressure fuel injection valve is temporarily stopped while the internal combustion engine is operative.

9. The fuel supply apparatus for an internal combustion engine according to claim 1 , further comprising a low pressure fuel injection valve that supplies the fuel fed from the low pressure fuel pump to the internal combustion engine selectively,
wherein the low pressure fuel injection valve is configured to include a plurality of port injection injectors, the number of which corresponds to the number of cylinders in the internal combustion engine,
the internal combustion engine includes a plurality of banks, each having a plurality of cylinders,
the high pressure fuel pump is mounted on a bank on one side, from among the plurality of banks, and
the fuel supply apparatus further includes a low pressure side fuel pressure sensor that detects a pressure of the fuel fed from the low pressure fuel pump to a port injection injector mounted on the bank on the one side, from among the plurality of port injection injectors.

10. The fuel supply apparatus for an internal combustion engineaccording to claim 1 , wherein the controller is further configured to detect a variation width per predetermined time of the pressure of the fuel fed from the low pressure fuel pump to the high pressure fuel pump, and
the controller is further configured to determine that the condition variation causing fuel vapor to form in the fuel fed from the low pressure fuel pump to the high pressure fuel pump has occurred based on a variation rate of the variation width when the variation width of the pressure of the fuel detected by the controller falls to the preset threshold pulsation width.

11. The fuel supply apparatus for an internal combustion engine according to claim 3 , wherein the target pressure is set in adv

Assignees

• Saito Kenichi
• Toyota Motor Co Ltd

Inventors

• Saito Kenichi

Classifications

• F02D41/3854 Primary

  with elements in the low pressure part, e.g. low pressure pump · CPC title

• F02M51/00 Primary

  Fuel-injection apparatus characterised by being operated electrically · CPC title

• F02D2250/02

  Fuel evaporation in fuel rails, e.g. in common rails · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title