Engine fuel injection controller

• US 5,474,049 A
• Filed: 09/13/1993
• Issued: 12/12/1995
• Est. Priority Date: 09/14/1992
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iwano, Hiroshi, Ohta, Kenji, Nagaishi, Hatsuo
• Primary Examiner(s): Moulis, Thomas N.
• Application Number:
  US08/119,680
• Time in Patent Office: 820 Days
• Field of Search: 123/518, 123/519, 123/520, 123/689, 123/698, 123/699, 73/580
• US Class Current: 123/520
• CPC Class Codes: F02D 41/0032 Controlling the purging of the canister as a function of the engine operating conditions
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02M 25/08 adding fuel vapours drawn from engine fuel reservoir electrical control of purge system F02D41/003

Abstract

An engine provided with a purge valve introducing fuel vapor from the fuel tank into the intake passage, a purge valve for opening and closing the passage, a device for setting a basic flowrate of the purge valve according to the engine running conditions, and a device for detecting the fuel concentration of the purge gas. Further, a device is provided for correcting the basic flowrate based on the fuel concentration of the purge gas so as to decrease the purge valve flowrate when the fuel concentration is high, and increase the purge valve flowrate when it is low. The purge valve opening is controlled according to this corrected flowrate, and purging can therefore be performed rapidly without adversely affecting the air-fuel ratio.

Claims

1. A fuel injection controller for an engine having a combustion chamber, an intake passage connected to said combustion chamber, a fuel tank for storing fuel, an injector for injecting fuel from said fuel tank into said intake passage, means for detecting running conditions of the engine, a purge passage for introducing fuel vapor from said fuel tank into said intake passage as a purge gas, and a purge valve which opens and closes said purge passage according to said running conditions, said controller comprising:

means for setting a basic fuel injection amount of said injector based on a predetermined target air-fuel ration and said running conditions,

means for detecting a real air-fuel ratio of air and fuel supplied to said combustion chamber,

means for feedback correcting said basic fuel injection amount by a predetermined correction unit amount such that said detected air-fuel ratio is identical to said target air-fuel ratio,

means for setting a flowrate of said purge valve according to said running conditions,

means for controlling an opening of said purge valve to obtain said flowrate,

means for determining a pressure difference before and after said purge valve, and

means for correcting said purge valve opening such that said opening is increased when said pressure difference is small, and said opening is decreased when said pressure difference is large.

2. A fuel injection controller as defined in claim 1, further comprising means for decreasing said basic fuel injection amount when said purge valve is open by an amount equivalent to said purge valve flowrate.

3. A fuel injection controller for an engine having a combustion chamber, an intake passage connected to said combustion chamber, a fuel tank for storing fuel, an injector for injecting fuel from said fuel tank into said intake passage, means for detecting running conditions of the engine, a purge passage for introducing fuel vapor from said fuel tank into said intake passage as a purge gas, and a purge valve which opens and closes said purge passage according to said running conditions, said controller comprising:

means for setting a basic fuel injection amount of said injector based on a predetermined target air-fuel ratio of air and fuel supplied to said combustion chamber,

means for feedback correcting said basic fuel injection amount by a predetermined correction unit amount such that said detected air-fuel ratio is identical to said target air-fuel ratio,

means for setting a flowrate of said purge valve according to said running conditions,

means for controlling an opening of said purge valve to obtain said flowrate,

means for detecting a fuel concentration of said purge gas,

first correcting means for correcting said purge valve opening such that said opening is decreased when said concentration is high, and said opening is increased when said concentration is low,

means for determining a pressure difference before and after said purge valve, and

second correcting means for correcting said purge valve opening such that said opening is increased when said determined pressure difference is small, and said opening is decreased when said determined pressure difference is large.

4. A fuel injection controller as defined in claim 3, further comprising means for decreasing said basic fuel injection amount when said purge valve is open by an amount equivalent to said purge valve flowrate.

5. A fuel injection controller for an engine having a combustion chamber, an intake passage connected to said combustion chamber, a fuel tank for storing fuel, an injector for injecting fuel from said fuel tank into said intake passage, means for detecting running conditions of the engine, a canister for collecting fuel vapor from said fuel tank, a purge passage for introducing said collected fuel vapor into said intake passage as a purge gas, and a purge valve which opens and closes said purge passage according to said running conditions, said controller comprising:

means for setting a basic fuel injection amount of said injector based on a predetermined target air-fuel ratio and said running conditions,

means for detecting a real air-fuel ratio of air and fuel supplied to said combustion chamber,

means for feedback correcting said basic fuel injection amount such that said detected air-fuel ratio is identical to said target air-fuel ratio,

means for setting a flowrate of said purge valve according to said running conditions,

means for controlling an opening of said purge valve to obtain said flowrate,

means for detecting a vibration frequency of said canister,

means for calculating a weight of said canister from said vibration frequency,

means for calculating a fixed concentration of said purge gas from said canister weight, and

means for correcting said purge valve opening such that said opening is decreased when said fuel concentration is high, and said opening is increased when said fuel concentration is low.

6. A fuel injection controller as defined in claim 5, further comprising means for decreasing said basic fuel injection amount when said purge valve is open by an amount equivalent to said purge flowrate.

7. A fuel injection controller for an engine having a combustion chamber, an intake passage connected to said combustion chamber, a fuel tank for storing fuel, an injector for injecting fuel from said fuel tank into said intake passage, means for detecting running conditions of the engine, a canister for collecting fuel vapor from said fuel tank, a purge passage for introducing said collected fuel vapor into said intake passage as a purge gas, and a purge valve which opens and closes said purge passage according to said running conditions, said controller comprising:

means for setting a basic fuel injection amount of said injector based on a predetermined target air-fuel ratio and said running conditions,

means for detecting a real air-fuel ratio of air and fuel supplied to said combustion chamber,

means for feedback correcting said basic fuel injection amount such that said detected air-fuel ratio is identical to said target air-fuel ration,

means for setting a flowrate of said purge valve according to said running conditions,

means for controlling an opening of said purge valve to obtain said flowrate,

means for detecting a vibration frequency of said canister,

means for calculating a weight of said canister from said vibration frequency,

means for calculating a fuel concentration of said purge gas from said canister weight,

first correcting means for correcting said purge valve opening such that said opening is decreased when said fuel concentration is high, and said opening is increased when said fuel concentration is low,

means for determining a pressure difference before and after said purge valve, and

second correcting means for correcting said purge valve opening such that said opening is increased when said pressure difference is small, and said opening is decreased when said pressure difference is large.

8. A fuel injection controller as defined in claim 7, further comprising means for decreasing said basic fuel injection amount when said purge valve is open by an amount equivalent to said purge flowrate.