FUEL SUPPLY SYSTEM FOR AN INTERNAL COMBUSTION ENGINE
First Claim
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1. A fuel vapor supply system configured to supply fuel vapor to an internal combustion engine having an intake passage, 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 is controlled;
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
wherein the check valve is configured to open when an intermediate purge passage pressure within the intermediate purge passage exceeds an intake passage pressure within the intake passage and the check valve is configured to close when the intermediate purge passage pressure does not exceed the intake passage pressure;
a pressure detection device configured to detect the intake passage pressure;
a controller coupled with the purge valve, wherein the controller is configured to;
control a degree of opening of the purge valve or 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 to control the purge valve to open with a predetermined opening degree or a predetermined 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; and
estimate the intermediate purge passage pressure within the intermediate purge passage at least partially based on the intake passage pressure detected by the pressure detection device.
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Abstract
A fuel supply system adapted to supply fuel to an internal combustion engine has both 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 estimates a pressure within an intermediate purge passage of the purge passage located between the check valve and the purge valve without relying on the use of a separate pressure detection device to provide information regarding the same.
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Citations
8 Claims
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1. A fuel vapor supply system configured to supply fuel vapor to an internal combustion engine having an intake passage, the fuel vapor supply system comprising:
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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 is controlled; 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 wherein the check valve is configured to open when an intermediate purge passage pressure within the intermediate purge passage exceeds an intake passage pressure within the intake passage and the check valve is configured to close when the intermediate purge passage pressure does not exceed the intake passage pressure; a pressure detection device configured to detect the intake passage pressure; a controller coupled with the purge valve, wherein the controller is configured to; control a degree of opening of the purge valve or 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 to control the purge valve to open with a predetermined opening degree or a predetermined 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; and estimate the intermediate purge passage pressure within the intermediate purge passage at least partially based on the intake passage pressure detected by the pressure detection device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system comprising:
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an internal combustion engine; an intake passage in fluid communication with the internal combustion engine wherein the intake passage is configured to supply intake air to the internal combustions engine; a fuel tank configured to store the fuel; a canister in fluid communication with the fuel tank wherein the canister is configured to store fuel from the fuel tank; a purge passage extending from the canister to connect with the intake passage; a purge valve disposed in the purge passage such that the fuel stored in the canister flows to the intake passage through the purge passage when the purge valve is open; a check valve disposed in the purge passage at a downstream position relative to a flow of fuel from the canister to the intake passage wherein the check valve is configured to prevent flow of intake air from the intake passage to the canister through the purge passage; a controller coupled with the purge valve wherein the controller is configured to regulate the purge valve at least partially based on an intake passage pressure within the intake passage and an intermediate purge passage pressure within an intermediate purge passage of the purge passage located between the purge valve and the check valve; and wherein the controller is further configured to estimate the intermediate purge passage pressure to be equal to the intake passage pressure or an atmospheric pressure dependent on a controlled opening and closing state of the purge valve.
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Specification