Fuel injection system for internal combustion engines and its method of control

• US 20010003977A1
• Filed: 12/11/2000
• Published: 06/21/2001
• Est. Priority Date: 12/13/1999
• Status: Abandoned Application

• Current Assignee: Aisan Kogyo Kabushiki Kaisha, Nippon Soken, Inc., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisan Kogyo Kabushiki Kaisha, Nippon Soken, Inc., Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Hayashi, Kenji, Kuroda, Shohei, Yamada, Jun
• Application Number:
  US09/733,040
• Publication Number:
  US 20010003977A1
• Time in Patent Office: Days
• US Class Current: 123/480
• CPC Class Codes: F02D 19/022 to adjust the fuel pressure, temperature or composition
• CPC Class Codes: F02D 19/024 by controlling fuel injectors
• CPC Class Codes: F02D 19/027 Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02D 19/029 Determining density, viscosity, concentration or composition
• CPC Class Codes: F02D 2200/0606 Fuel temperature
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02M 21/0212 comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
• CPC Class Codes: F02M 21/0284 Arrangement of multiple injectors or fuel-air mixers per combustion chamber
• CPC Class Codes: F02M 21/0287 characterised by the transition from liquid to gaseous phase F02M21/06 takes precedence; Injection in liquid phase; Cooling and low temperature storage
• CPC Class Codes: F02M 25/08 adding fuel vapours drawn from engine fuel reservoir electrical control of purge system F02D41/003
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A fuel injection system that can maintain a high accuracy level in adjusting the quantity of fuel injection in a system in which the first injector injects fuel in the liquid phase and the second injector injects fuel in the gaseous phase. The quantity of fuel injection of each injector is adjusted respectively in accordance with the fuel quantity required each time. The temperature of the first injector is estimated based on the temperature of the engine'"'"'s cooling water and the temperature of the fuel in the fuel passage from the fuel tank to the first injector, and the quantity of vapor generated in the fuel passage is determined according to the estimated temperature and the fuel pressure in the fuel passage. The quantity of fuel injection of each injector is adjusted according to the determined quantity of vapor generated.

Claims

1. A fuel injection system for internal combustion engines comprising:

a fuel tank;

a first injector that supplies fuel stored in the fuel tank to an internal combustion engine in a liquid phase;

a second injector that supplies fuel stored in the fuel tank to the internal combustion engine in a gaseous phase; and

a controller that estimates the temperature of the first injector based on the temperature of the internal combustion engine and fuel temperature inside a fuel passage from the fuel tank to the first injector, and which adjusts fuel injection quantities of the first and second injectors in accordance with the fuel quantity required by the internal combustion engine based on the estimated temperature of the first injector.

2. The system according to

claim 1

, wherein the controller further determines the quantity of vapor generated in the fuel passage based on the estimated temperature of the first injector and fuel pressure in the fuel passage, and adjusts the fuel injection quantities of the first and second injectors based on the determined quantity of the generated vapor.

3. The system according to

claim 2

, wherein the quantity of generated vapor is determined based on properties of the fuel in the fuel tank.

4. A system according to

claim 3

, wherein the properties of the fuel are determined based on fuel temperature and fuel pressure in the fuel tank.

5. A system according to

claim 2

, wherein the controller sets the quantity of fuel injection of the second injector to zero when the quantity of generated vapor is less than a predetermined value.

6. A system according to

claim 3

, wherein the controller sets the quantity of fuel injection of the second injector to zero when the quantity of generated vapor is less than a predetermined value.

7. A system according to

claim 4

, wherein the controller sets the quantity of fuel injection of the second injector to zero when the quantity of generated vapor is less than a predetermined value.

8. A system according to

claim 5

, wherein the controller further estimates presence of vapor in the fuel passage based on fuel temperature and fuel pressure in the fuel passage, and adjusts the quantities of fuel injected by the first and second injectors depending on the estimated presence or absence of the vapor when the quantity of generated vapor is more than a predetermined value.

9. A system according to

claim 8

, wherein the controller sets the quantity of fuel injection of the first injector to zero if it is estimated that vapor exists in the fuel passage, and initiates fuel injection first with the first injector when it is estimated that there is no vapor in the fuel passage, gradually increases the ratio of the quantity of fuel injection of the first injector relative to the second injector in accordance with the required fuel quantity.

17. A method of

claim 5

further comprising:

estimating whether or not vapor exits in the fuel passage based on the fuel temperature and fuel pressure in the fuel passage; and

adjusting fuel injection quantities of the first and second injectors depending on the estimated presence or absence of vapor when the determined quantity of vapor generation is more than a predetermined value.

18. A method of

claim 17

further comprising:

setting the quantity of fuel injection of the first injector to zero when it is estimated that vapor exists in the fuel passage; and

initiating fuel injection first with the first injector when it is estimated that there is no vapor in the fuel passage, and gradually increasing the ratio of the quantity of fuel injection of the first injector relative to the second injector in accordance with the required fuel quantity.

10. A fuel injection method for internal combustion engines comprising:

injecting fuel stored in the fuel tank into an internal combustion engine in a liquid phase by means of a first injector;

injecting stored in the fuel tank into an internal combustion engine in a gaseous phase by means of a second injector;

estimating the temperature of the first injector based on temperature of the internal combustion engine and fuel temperature inside a fuel passage from the fuel tank to the first injector; and

adjusting fuel injection quantities of the first and second injectors in accordance with a fuel quantity required by the internal combustion engine based on the estimated temperature of the first injector.

11. A method according to

claim 10

further comprising:

determining the quantity of vapor generated in the fuel passage based on the estimated temperature of the first injector and fuel pressure in the fuel passage, and

adjusting the fuel injection quantities of the first and second injectors based on the determined quantity of the generated vapor.

12. A method of

claim 11

, wherein the quantity of generated vapor is determined based on properties of the fuel in the fuel tank.

13. A method of

claim 12

, wherein the properties of the fuel are determined based on fuel temperature and fuel pressure in the fuel tank.

14. A method of

claim 11

further comprising setting the quantity of fuel injection of the second injector to zero when the quantity of generated vapor is less than a predetermined value.

15. A method of

claim 12

further comprising setting the quantity of fuel injection of the second injector to zero executed by the controller when the quantity of generated vapor is less than a predetermined value.

16. A method of

claim 13

further comprising the step of setting the quantity of fuel injection of the second injector to zero executed by the controller when the quantity of generated vapor is less than a predetermined value.