EP0222019B1 - Fuel controller for engine - Google Patents

Fuel controller for engine Download PDF

Info

Publication number: EP0222019B1
Authority: EP; European Patent Office
Prior art keywords: air; engine; fuel ratio; fuel; sensor
Prior art date: 1985-05-07
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.): Expired

Application number

EP19860902028

Other languages

German (de)

English (en)

French (fr)

Other versions

EP0222019A1 (en

Inventor

Seiji Mitsubishi Denki Kabushiki Wataya

Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

Mitsubishi Electric Corp

Original Assignee

Mitsubishi Electric Corp

Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)

1985-05-07

Filing date

1986-03-27

Publication date

1989-05-17

1986-03-27 Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp

1987-05-20 Publication of EP0222019A1 publication Critical patent/EP0222019A1/en

1989-05-17 Application granted granted Critical

1989-05-17 Publication of EP0222019B1 publication Critical patent/EP0222019B1/en

Status Expired legal-status Critical Current

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Classifications

- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1486—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
- F02D41/1488—Inhibiting the regulation
- F02D41/149—Replacing of the control value by an other parameter
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
- F02D41/187—Circuit arrangements for generating control signals by measuring intake air flow using a hot wire flow sensor

Definitions

This invention relates to a fuel controller for an engine improved for the accuracy of an air fuel ratio at a high load time when fuel is injected from a gasoline engine employing an air flow sensor based on a heat radiation principle (e.g., a hot-wire type air flow sensor).
a heat radiation principle e.g., a hot-wire type air flow sensor
a fuel controller for an engine of an automobile generally controls an optimum amount of fuel supplied to the engine on the basis of an intake air quantity from an air flow sensor and the rotating speed of the engine from a rotary detector.
the construction of a conventional fuel controller of an engine is shown in Fig. 6.
Fig. 6 1 designates an engine
2 designates a suction manifold.
An electromagnetic fuel injection valve 3 is provided in the suction manifold 2, and the fuel injection valve 3 is controlled by a controller 8.
the suction manifold 2 is coupled with a surge tank 4, which is connected to a suction conduit 5.
a throttle valve 6 is disposed in the suction conduit 5.
a hot-wire type air flow sensor 7 is provided in the conduit 5. The output of the sensor 7 is fed to the controller 8.
the rotating speed of the engine 1 is detected by a rotary detector 9, which applies the detected output to the controller 8.
the controller 8 controls the fuel injection valve 3 by the output of the detector 9 and the output of the sensor 7.
the controller 8 is constructed as shown in Fig. 7, the output of the sensor 7 is converted by a digital converter 81 into a digital signal, and fed to a microprocessor 83.
the output of the detector 9 is supplied through an interface circuit 82 to the microprocessor 83.
the microprocessor 83 calculates a predetermined fuel amount on the basis of the output from the sensor 7 and the information from the detector 9, amplifies it via an amplifier 86 and controls the valve 3.
a random access memory (RAM) 84 and a read only memory (ROM) 85 are connected to the microprocessor 83.
the RAM 84 is used for calculating, and the ROM 85 stores the calculating sequence and the control data.
the output waveform of the sensor 7 becomes as shown in Fig. 8(b) in the specific rotating speed range (generally 1000 to 3000 ppm) near the WOT due to the blow-off from the engine 1, and the portion indicated by the hatched lines is excessively added to the true air flow rate.
the hot-wire type air flow sensor 7 based on the heat radiation principle detects as intake amount and outputs in irrespective of the air flowing direction.
the detecting error due to the blow-off depends upon the rotating speed as shown in Fig. 9, and is generated ordinarily in the vicinity that the suction conduit vacuum becomes near -50 mmHg and arrives at 50% at the maximum in the WOT range.
the upper limit value must be set to the intake air flow rate characteristic of the engine to be used at the ambient temperature in the sea level, it should become the upper limit value of mass flow rate at the ambient temperature at the sea level.
the upper limit of the output of the air flow sensor is heretofore stored in advance in the memory in the controller in response to the intake air flow rate characteristic of the engine, and even if the output of the sensor abnormally increases, a large error is eliminated in the air flow rate.
this method since the upper limit is decided in response to the engine near the ambient temperature at a sea level, this method has such a drawback that the error in the airfuel ratio increases in the high altitude traveling or in high and low temperature atmosphere.
the present invention has been made to eliminate said prior art disadvantages and an object thereof is to provide a fuel controller for an engine which can obviate air fuel ratio error due to atmospheric pressure (in high altitude) and intake air temperature and obtain stable burning state under all operating conditions of the engine.
a fuel controller for an engine comprises an air flow sensor which detects the engine intake air quantity on the basis of a heat radiation principle; an air-fuel ratio sensor which detects, from the engine exhaust gas, whether the air-fuel ratio is rich or lean compared with a predetermined value; an electromagnetic fuel injection valve for injecting fuel; and a control unit which controls the opening time of the valve in dependence on the sensed air-fuel ratio and the intake air quantity; characterised in that at high engine load, the control unit controls the opening time of the valve in dependence on the sensed air-fuel ratio to maintain the said ratio at the predetermined value by feedback when the sensed air-fuel ratio is rich, and when the sensed air-fuel ratio is lean, the control unit controls the opening time of the valve in open-loop control in dependence on the sensed air flow quantity as a main parameter.
the present invention detects the air fuel ratio of rich side by an air fuel ratio sensor to suppress the air fuel ratio error due to the blow-off of the intake air when the engine is fully opened, stable burning state can be attained under all operating conditions of the engine.
EP-A-87801 describes a fuel control system including a plurality of sensors sensing various operation parameters of an engine, a digital computer controlling the quantity of fuel supplied to the engine depending on the outputs from the sensors, including a hot-wire airflow sensor, a pulse generating circuit generating a pulse signal for controlling the quantity of supplied fuel in response to the output from the digital computer, and fuel supplying means for supplying fuel on the basis of the pulse signal generated from the pulse generating circuit.
This fuel control system operates by computing the quantity of air taken into the engine on the basis of the output from one of the sensors, integrating the quantity of intake air computed in the first step, determining the level for setting the period of generation of the pulse signal on the basis of the output from one of the sensors, and generating pulses of predetermined pulsewidth from the pulse generating circuit when a predetermined relation is attained between the level determined in the third step and the result of integration in the second step.
the measured air-fuel ratio is used as a control factor, only when the engine is not operating at high load. Under high power, the engine is controlled on the basis of the instantaneous intake air quantity and the engine speed. This system is therefore not able to compensate for errors in air flow detection by a heat-radiation sensor at high power.
Fig. 1 is a view illustrating the entire construction of an embodiment of a fuel controllerfor an engine according to the present invention
Fig. 2 is a block diagram illustrating the internal construction of the controller in the fuel controller of the engine in Fig. 1
Fig.3 3 is a characteristic diagram of an airfuel ratio sensor in the fuel controller of the engine of the invention
Fig. 4 is a time chart for explaining the operation of the invention
Fig. 5 is a flow chart illustrating the flow of the operation of the fuel controller of the engine
Fig. 6 is a view illustrating the entire construction of the fuel controller of the conventional engine
Fig. 7 is a block diagram showing the internal construction of the controller in the fuel controller of the engine of Fig. 6, Fig.
FIG. 8 is a characteristic diagram of an airflow sensor in the fuel controller of the engine of Fig. 6,
Fig. 9 is a view showing the detecting error of the air flow sensor in the fuel controller of the engine of Fig. 6,
Fig. 10 is an output characteristic diagram with respect to the rotating speed of the engine of the air flow sensor, and
Fig.11 is a view showing an error with respect to an altitude due to the air flow sensor in the fuel controller of the conventional engine.
Fig. 1 is a view showing the construction of an embodiment.
the same reference numerals as in Fig. 6 designate the corresponding components, and description of the construction is omitted, and the portion different from Fig. 6 will be mainly described.
an air fuel ratio sensor 10 is newly provided in the construction of Fig. 6, in Fig. 1, and the sensor 10 can linearly detect the air fuel ratio from the exhaust gas components of an engine 1.
the other construction is the same as in Fig. 6.
the sensor 10 produces, as shown in Fig. 2, an output to an A/D converter 81 in a controller 8.
Fig. 2 shows a block diagram of the sensor 10 corresponding to the conventional controller shown in Fig. 7, and the construction of Fig. 2 is different from Fig. 7 at the point that the output of the sensor 10 is newly delivered to the A/D converter 81, and the other construction is the same as in Fig. 7.
a combination of a zirconia type oxygen battery (atmospheric air is supplied to one side, and exhaust gas affected by the influence of an oxygen pump is supplied to the other) exhibiting a switching characteristic at stoichiometric air fuel ratio and an oxygen pump is heretofore known, and NOx in the components of the exhaust gas and oxygen in CO are reduced to supply oxygen to the opposite atmospheric pressure side of the oxygen battery by applying a voltage to the oxygen pump to detect the air fuel ratio of rich side.
the output voltage with respect to the air fuel ratio of the sensor 10 is as shown in Fig. 3.
the pulse width of the fuel injection valve 3 is no longer controlled in dependence on the engine air intake quantity, but instead, is controlled by feedback to maintain the air-fuel ratio substantially equal to the predetermined value a.
the pulse width of the fuel injection valve, and the value of the air-fuel ratio follow the curves b, so that the actual air-fuel ratio oscillates about the value a as a mean value. In this way, stable substantially complete combustion is obtained.
step 100 the intake air quantity Qa and the rotating speed Ne of the engine are read out as essential parameters.
step 101 the drive pulse T , of the fuel injection valve 3 is calculated from the input information, and in next step 102, it is judged whether the output of the sensor 10 is larger than a predetermined air-fuel ratio (e.g., 12) or not. If larger (lean side) the final drive pulse width T is determined as ⁇ ⁇ (in step 104).
a predetermined air-fuel ratio e.g. 12
a flag is set as shown in Fig. 4(e), (in step 105).
an integration complementary term C FB is calculated as a value corresponding to the required air-fuel ratio a, as shown in Fig. 4(d), (in step 106).
the coefficient is applied to the previously calculated injector drive pulse width value to determine a modified pulse width Tc equal to t B xC FB , in steps 108 to 110. Specifically, if the modified pulse width value Tc is determined to be smaller than the initial pulse width value TB , the control unit provides as its output an injector drive pulse having the width T c .
This operation is repeated, and the actual air- fuel ratio is controlled to be fed back with the air- fuel ratio as a center.
This operation is continued while the drive pulse width Tc of the valve 3 due to the feedback control is smaller than the drive pulse width TB of the valve 3 calculated from the intake air quantity Qa and the engine rotation speed Ne, and when Tc becomes larger than TB , the flag is reset in step 111, and the valve 3 is controlled with the pulse width Te .
the air-fuel ratio on the rich side has been controlled by feedback by using an air-fuel sensor 10 capable of linearly detecting the air-fuel ratio.
an air-fuel ratio sensor 10 which inverts the output in a switching manner at the predetermined air-fuel ratio (e.g., 12) may be used to provide similar advantages.
the present invention is mainly utilized for a fuel controller of an engine for an automobile, but is not limited to automobiles.
the present invention may be applied to the fuel control of a ship and aircraft engine which employ fuel such as gasoline.

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Engineering & Computer Science (AREA)
Chemical & Material Sciences (AREA)
Combustion & Propulsion (AREA)
Mechanical Engineering (AREA)
General Engineering & Computer Science (AREA)
Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Combined Controls Of Internal Combustion Engines (AREA)

EP19860902028 1985-05-07 1986-03-27 Fuel controller for engine Expired EP0222019B1 (en)

Applications Claiming Priority (2)

Application Number	Priority Date	Filing Date	Title
JP98528/85		1985-05-07
JP9852885A JPS61255238A (ja)	1985-05-07	1985-05-07	エンジンの燃料制御装置

Publications (2)

Publication Number	Publication Date
EP0222019A1 EP0222019A1 (en)	1987-05-20
EP0222019B1 true EP0222019B1 (en)	1989-05-17

Family

ID=14222172

Family Applications (1)

Application Number	Title	Priority Date	Filing Date
EP19860902028 Expired EP0222019B1 (en)	1985-05-07	1986-03-27	Fuel controller for engine

Country Status (4)

Country	Link
EP (1)	EP0222019B1 (ja)
JP (1)	JPS61255238A (ja)
DE (1)	DE3663380D1 (ja)
WO (1)	WO1986006792A1 (ja)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number	Priority date	Publication date	Assignee	Title
JP5616264B2 (ja) *	2011-03-24	2014-10-29	株式会社ケーヒン	エンジン制御装置

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number	Priority date	Publication date	Assignee	Title
DE2229928C3 (de) *	1972-06-20	1981-03-19	Robert Bosch Gmbh, 7000 Stuttgart	Verfahren und Vorrichtung zur Verminderung von schädlichen Anteilen der Abgasemission von Brennkraftmaschinen
DE2417187C2 (de) *	1974-04-09	1982-12-23	Robert Bosch Gmbh, 7000 Stuttgart	Verfahren und Vorrichtung zur Regelung des Betriebsverhaltens einer Brennkraftmaschine
GB1568960A (en) *	1975-10-22	1980-06-11	Lucas Industries Ltd	Fuel control system for an internal combustion engine
DE2633617C2 (de) *	1976-07-27	1986-09-25	Robert Bosch Gmbh, 7000 Stuttgart	Verfahren und Vorrichtung zur Bestimmung von Einstellgrößen bei einer Brennkraftmaschine, insbesondere der Dauer von Kraftstoffeinspritzimpulsen, des Zündwinkels, der Abgasrückführrate
JPS6060019B2 (ja) *	1977-10-17	1985-12-27	株式会社日立製作所	エンジンの制御方法
DE2840793C3 (de) *	1978-09-20	1995-08-03	Bosch Gmbh Robert	Verfahren und Einrichtung zum Bestimmen der von einer Brennkraftmaschine angesaugten Luftmenge
JPS55139938A (en) *	1979-04-19	1980-11-01	Japan Electronic Control Syst Co Ltd	Suction air amount computing method of internal combustion engine
JPS57148041A (en) *	1981-03-09	1982-09-13	Suzuki Motor Co Ltd	Controller of air-fuel ratio in carburetor
JPS58131329A (ja) *	1982-01-29	1983-08-05	Nippon Denso Co Ltd	燃料噴射制御方法
JPS58150046A (ja) *	1982-03-03	1983-09-06	Hitachi Ltd	燃料噴射制御装置
JPS603446A (ja) *	1983-06-21	1985-01-09	Mitsubishi Electric Corp	機関の空燃比制御装置

1985
- 1985-05-07 JP JP9852885A patent/JPS61255238A/ja active Pending
1986
- 1986-03-27 WO PCT/JP1986/000146 patent/WO1986006792A1/en active IP Right Grant
- 1986-03-27 DE DE8686902028T patent/DE3663380D1/de not_active Expired
- 1986-03-27 EP EP19860902028 patent/EP0222019B1/en not_active Expired

Also Published As

Publication number	Publication date
DE3663380D1 (en)	1989-06-22
WO1986006792A1 (en)	1986-11-20
JPS61255238A (ja)	1986-11-12
EP0222019A1 (en)	1987-05-20

Legal Events

Date	Code	Title	Description
1987-04-04	PUAI	Public reference made under article 153(3) epc to a published international application that has entered the european phase	Free format text: ORIGINAL CODE: 0009012
1987-05-20	AK	Designated contracting states	Kind code of ref document: A1 Designated state(s): DE FR GB
1987-07-15	17P	Request for examination filed	Effective date: 19870518
1987-11-25	17Q	First examination report despatched	Effective date: 19871012
1989-04-01	GRAA	(expected) grant	Free format text: ORIGINAL CODE: 0009210
1989-05-17	AK	Designated contracting states	Kind code of ref document: B1 Designated state(s): DE FR GB
1989-06-22	REF	Corresponds to:	Ref document number: 3663380 Country of ref document: DE Date of ref document: 19890622
1989-07-07	ET	Fr: translation filed
1990-03-22	PLBE	No opposition filed within time limit	Free format text: ORIGINAL CODE: 0009261
1990-03-22	STAA	Information on the status of an ep patent application or granted ep patent	Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT
1990-05-09	26N	No opposition filed
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