Variable displacement closed loop fuel controlled internal combustion engine

• US 4,134,261 A
• Filed: 08/15/1977
• Issued: 01/16/1979
• Est. Priority Date: 09/13/1976
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iizuka, Haruhiko, Fukasawa, Noburu
• Primary Examiner(s): Hart, Douglas
• Application Number:
  US05/824,849
• Time in Patent Office: 519 Days
• Field of Search: 60/276, 60/277, 60/285, 60/299
• US Class Current: 60/276
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/1443 with one sensor per cylinder or group of cylinders

Abstract

An internal combustion engine operable in variable displacement modes is provided with separate exhaust systems for individual cylinder groups and a set of exhaust gas sensor and catalytic converter for each exhaust system. An electronic fuel injection control unit is arranged to respond to one of the signals from the gas sensor which is indicative of mixture richer than the other to effect correction of the duration of fuel injection pulse. Each catalytic converter is provided with a temperature sensor to detect when the temperature therein falls below the normal catalytic reaction temperture. A variable displacement control unit responds to the output from the temperature sensors by alternately deactivating the cylinder groups during low power operation.

Claims

1. A multi-cylinder internal combustion engine having first and second cylinders and first and second electrically energizable fuel injectors respectively for said cylinders adapted when energized to discharge fuel thereinto and an air intake passage for said cylinders, comprising:

first and second exhaust systems associated with said first and second cylinders respectively;

first and second means for respectively generating first and second signals indicative of the air fuel ratio within said first and second exhaust systems respectively;

first and second catalytic converters disposed in said first and second exhaust systems respectively, and effective when supplied with exhaust gases containing air and fuel in a certain ratio to accelerate simultaneously the oxidation of unburned fuel and the reduction of nitrogen oxides when said exhaust gases are within an effective range of temperatures;

first and second temperature sensors for detecting when said exhaust gases in said first and second catalytic converters are within said effective range of temperatures;

means operable when said engine is at light load to selectively energize one of said first and second fuel injectors in synchronism with operation of the engine in response to the time of occurrence of an output from said first and second temperature sensors and operable when said engine is at heavy load to simultaneously energize said first and second fuel injectors in synchronism with operation of the engine, and adjusting the period of energization of said fuel injectors in accordance with the one of said first and second signals which is indicative of the air-fuel ratio within one of the exhaust systems being richer than the air-fuel ratio within the other exhaust system, whereby the ratio of air and fuel supplied to said cylinders is varied in response to the direction of the deviation of said one of said first and second signals from a fixed reference so as to reduce the deviation of the ratio of air and fuel in the respective exhaust systems from said certain ratio.

2. A multi-cylinder internal combustion engine as claimed in claim 1, further comprising means for simultaneously energizing said first and second fuel injectors in response to the outputs from said first and second temperature sensors when the exhaust gases in said first and second exhaust systems are below said effective ranges.

3. A multi-cylinder internal combustion engine as claimed in claim 1, wherein said first catalytic converter is located within said second catalytic converter to permit exchange of heat between said converters.

4. A multi-cylinder internal combustion engine as claimed in claim 1, wherein said injector energizing and period adjusting means comprises:

means for generating an electrical signal at one of first and second binary levels when the engine is at light or heavy load, respectively;

means for generating an injection pulse in synchronism with the revolution of the engine, the duration of the injection pulse being dependent upon the voltage of said one of said first and second signals;

a first J-K flip-flop operable to change its binary state in response to the trailing edge of an injection pulse which occurs subsequent to the time of occurrence of said electrical signal at one of first and second binary levels;

a second J-K flip-flop operable to change its binary state in response to the trailing edge of an injection pulse which occurs subsequent to the time of occurrence of said output from said first temperature sensor;

a third J-K flip-flop operable to change its binary state in response to the trailing edge of an injection pulse which occurs subsequent to the time of occurrence of said output from said second temperature sensor;

a bistable device responsive to the outputs from said second and third J-K flip-flops to change its binary states; and

first and second AND gates for selectively feeding said injection pulse to said first and second fuel injectors in response to the binary states of said bistable device and in response to the binary state of said first J-K flip-flop.

5. A multi-cylinder internal combustion engine having first and second cylinders and first and second electrically energizable fuel injectors respectively for said cylinders adapted when energized to discharge fuel thereinto, and an air intake passage for said cylinders, comprising:

first and second exhaust systems associated with said first and second cylinders respectively;

first and second means for respectively generating first and second signals indicative of the air fuel ratio within said first and second exhaust systems respectively;

first and second catalytic converters disposed in said first and second exhaust systems respectively, and effective when supplied with exhaust gases containing air and fuel in a certain ratio to accelerate simultaneously the oxidation of unburned fuel and the reduction of nitrogen oxides when said exhaust gases are within an effective range of temperatures;

first and second temperature sensors for detecting when said exhaust gases in said first and second catalytic converters are within said effective range of temperatures;

means for energizing said fuel injectors for a period of time dependent upon the one of said first and second signals which is greater in magnitude than the other such that the ratio of air and fuel supplied to said cylinders is varied in the direction of the deviation of said one of said first and second signals from a fixed reference to reduce the deviation of the ratio of air and fuel in the respective exhaust systems from said certain ratio; and

means operable when said engine is at light load to alternately deactive one of said first and second fuel injectors in response to the time of occurrence of an output from said temperature sensors.

6. A multi-cylinder internal combustion engine having first and second cylinders and first and second electrically energizable fuel injectors for said cylinders respectively adapted when energized to discharge fuel thereinto, comprising:

a variable displacement control means including first and second exhaust systems associated with said first and second cylinders respectively, first and second catalytic converters respectively disposed in said first and second exhaust systems, said converters being effective when supplied with exhaust gases containing air and fuel in a certain ratio to accelerate simultaneously the oxidation of unburned fuel and the reduction of nitrogen oxides when said exhaust gases are within an effective range of temperatures, first and second temperature sensors for detecting when said exhaust gases in said first and second catalytic converters are within said effective range of temperatures, and a control unit operable when the engine is at light load to selectively respond to the time of occurrence of an output from said first and second temperature sensors to energize one of said first and second fuel injectors and operable when the engine is at heavy load to energize said first and second fuel injectors simultaneously; and

a closed loop fuel control means including means for generating a first signal indicative of the air fuel ratio within said first exhaust system upstream from said first catalytic converter, means for generating a second signal indicative of the air fuel ratio in said second exhaust system upstream from said second catalytic converter, and means for adjusting the period of energization of said fuel injectors in accordance with the one of said first and second signals which is greater in magnitude than the other to vary the ratio of air and fuel supplied to said cylinders in response to the direction of the deviation of said one of said first and second signals from a fixed reference so as to reduce the deviation of the ratio of air and fuel in the respective exhaust systems from said certain ratio.