Fuel supply system for an internal combustion engine

• US 10,273,892 B2
• Filed: 07/09/2015
• Issued: 04/30/2019
• Est. Priority Date: 07/10/2014
• Status: Active Grant

• Current Assignee: Aisan Kogyo Kabushiki Kaisha, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisan Kogyo Kabushiki Kaisha, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Miyazaki, Ryuji, Tsutsumi, Hidetoshi, Nakatsuka, Tomonori, Morihiro, Kinji, Honda, Koji
• Primary Examiner(s): Hamaoui, David E
• Assistant Examiner(s): Scharpf, Susan E
• Application Number:
  US14/794,998
• Publication Number:
  US 20160010570A1
• Time in Patent Office: 1,391 Days
• Field of Search: 123445
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 41/004 Control of the valve or purge actuator, e.g. duty cycle, closed loop control of position
• 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: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation
• CPC Class Codes: F02M 61/145 the injection nozzle opening into the air intake conduit

Abstract

A fuel supply system for use with an internal combustion engine has a check valve and a purge valve disposed in a purge passage that extends from a canister to connect with an intake passage of the internal combustion engine. A controller regulates the purge valve open with a first opening degree or a first duty ratio during a purge operation. The controller may also regulate the purge valve to open with a second opening degree larger than the first opening degree or a second duty ratio larger than the first duty ratio a predetermined time after initiating the purge operation.

Claims

1. A fuel vapor supply system configured to supply fuel vapor to an internal combustion engine having an intake passage and a fuel injector, the fuel vapor supply system comprising:

a canister configured to store the fuel vapor;

a purge passage extending from the canister to connect to the intake passage of the internal combustion engine wherein the purge passage allows the fuel vapor stored in the canister to flow to the internal combustion engine through the purge passage;

a purge valve disposed in the purge passage wherein the purge valve is configured to regulate a flow rate of the fuel vapor flowing from the canister to the intake passage;

a check valve disposed in the purge passage between the purge valve and the intake passage wherein the check valve is configured to permit the flow of the fuel vapor from the canister to the intake passage and further wherein the check valve is configured to prevent the flow of air from the intake passage to the canister;

wherein the purge passage has an intermediate purge passage that extends from the purge valve to the check valve; and

a controller coupled with the purge valve and the fuel injector, wherein the controller is configured to;

control a degree of opening of the purge valve or control a duty ratio wherein the duty ratio is defined as a ratio of a valve opening time to a predetermined frequency period and further wherein control of the degree of opening of the purge valve or control of the duty ratio regulates the flow rate of the fuel vapor flowing across the purge valve;

perform a purge control and perform a reduction control of a fuel injection quantity of fuel injected from the injector, wherein the purge control is defined as an operation that controls the purge valve to open with a first opening degree or a first duty ratio such that the fuel vapor stored in the canister flows from the canister to the internal combustion engine via the purge passage and the intake passage because of a negative pressure in the intake passage wherein the negative pressure is defined as a pressure less than an atmospheric pressure, while the fuel vapor flows across the purge valve, through the intermediate purge passage, and across the check valve in the purge passage,

wherein the reduction control is defined as an operation that begins when a predetermined arrival delay time has elapsed from starting the purge control wherein the reduction control regulates the fuel injector such that a quantity fuel injected by the fuel injector is reduced to compensate for a quantity of the fuel vapor supplied to the internal combustion engine; and

wherein the controller is further configured to;

determine whether a predetermined execution condition for the purge control is satisfied;

predict an execution condition satisfaction time when the predetermined execution condition for the purge control will be satisfied wherein the prediction of the execution condition satisfaction time is performed prior to the determination of whether the predetermined execution condition is satisfied;

determine whether the execution condition satisfaction time has been predicted, wherein the determination is performed if the predetermined execution condition is not satisfied;

perform a pre-drive operation in which the purge valve is open with the first opening degree or the first duty ratio or with a second opening degree larger than the first opening degree or a second duty ratio larger than the first duty ratio wherein the pre-drive operation is performed after the execution condition satisfaction time has been predicted and further wherein the pre-drive operation is initiated at a start time before the execution condition satisfaction time by a predetermined pre-drive time;

control the purge valve to open with the first opening degree or the first duty ratio if the predetermine execution condition is satisfied; and

prevent the reduction control during the pre-drive operation.

2. The fuel vapor supply system according to claim 1, further comprising one of either a pressure detection device disposed within the intermediate purge passage for detecting a pressure within the intermediate purge passage, or the controller is further configured to estimate the pressure within the intermediate purge passage based on a pressure within the intake passage, and wherein the controller is further configured to determine the pre-drive time based on a difference between the pressure within the intake passage and the pressure within the intermediate purge passage at a time when the prediction of the execution condition satisfaction time is made.

3. The fuel vapor supply system according to claim 1, further comprising one of either a pressure detection device disposed within the intermediate purge passage for detecting a pressure within the intermediate purge passage, or the controller is further configured to estimate the pressure within the intermediate purge passage based on a pressure within the intake passage, and wherein the controller is further configured to terminate the pre-drive operation at a time when the predetermined pre-drive time has elapsed, when a difference between the pressure within the intake passage and the pressure within the intermediate purge passage falls beneath a predetermined value, or when the pressure within the intermediate purge passage exceeds the pressure within the intake passage.

4. The fuel vapor supply system according to claim 1, wherein the second opening degree corresponds to a maximum opening degree of the purge valve and the second duty ratio corresponds to a maximum duty ratio.

5. The fuel vapor supply system according to claim 1, further comprising one of either a pressure detection device disposed within the intermediate purge passage for detecting a pressure within the intermediate purge passage, or the controller is further configured to estimate the pressure within the intermediate purge passage based on a pressure within the intake passage, and wherein the controller is further configured to adjust a value of the second opening degree or the second duty ratio according a difference between the pressure within the intake passage and the pressure within the intermediate purge passage.

6. The fuel vapor supply system according to claim 1, wherein:

the fuel vapor supply system further comprises a pressure detection device configured to detect the pressure within the intake passage;

the fuel vapor supply system further comprises one of either a pressure detection device disposed within the intermediate purge passage for detecting a pressure within the intermediate purge passage, or the controller is further configured to estimate the pressure within the intermediate purge passage based on a pressure within the intake passage;

the controller is further configured to estimate the pressure within the intermediate purge passage;

wherein the controller estimates the pressure within the intermediate purge passage to be equal to a smallest value of detected values of the pressure within the intake passage should the purge valve be fully closed; and

wherein the controller estimates the pressure within the intermediate purge passage to be equal to the pressure within the intake passage detected at a time when a predetermined pressure variation transition time has elapsed after starting the purge control should the purge valve not be fully closed.

7. The fuel vapor supply system according to claim 6, wherein the controller is further configured to adjust a duration of the predetermined pressure variation transition time based on a difference between the pressure within the intake passage detected by the pressure detection device and the pressure within the intermediate purge passage estimated when the purge valve is fully closed.

8. The fuel vapor supply system according to claim 6, wherein the controller estimates the pressure within the intermediate purge passage to be equal to the atmospheric pressure provided that the pressure within the intake passage is higher than the atmospheric pressure at the time when the predetermined pressure variation transition time has elapsed after initiating the purge control should the purge valve not be fully closed.