US4392468A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling the idling speed of an engine
Assignee: Toyota Motor Corp
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Filing: 1981-07-09
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Granted: 1983-07-12
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Expires: 2001-07-09
Abstract
Abstract An engine has a main intake passage in which a throttle valve is disposed. A bypass passage is branched off from the main intake passage upstream of the throttle valve and is connected to the main intake passage located downstream of the throttle valve. A flow control valve, actuated by a stepper motor, is arranged in the bypass passage. In an electronic control unit, the mean value of the step position is stored, and a lower limit of the step position is calculated from the mean value of the step position. When the engine is idling after it has been and the stepper motor is rotated in a direction wherein the flow control valve closes the rotating operation of the stepper motor is stopped when the step position of the stepper motor reaches thelower limit of the step position. This allows for precise control of the flow control valve, while preventing the sudden rapid closing of the valve, thus improving engine performance.
Inventors
- 👤 Mamoru Kobashi
- 👤 Hiroshi Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:48
CPC Classifications
F; F02; F02D; F02D31/00; F02D31/001; F02D31/002; F02D31/003; F02D31/005; F02D11/00; F02D11/06; F02D11/10; F02D2011/101; F02D2011/102
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
158 words
A method of controlling the idling speed of an engine comprising a main intake passage, a throttle valve arranged in the main intake passage, a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve, a control valve arranged in the bypass passage, and a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage, said method comprising the steps of: detecting a step position of the stepper motor; obtaining the mean value of the step position over a predetermined time; calculating the lower limit of the step position, said lower limit being obtained by subtracting a predetermined step number from said mean value of the step position; and stopping the stepper motor from rotating in a direction wherein the control valve closes when the step position of the stepper motor reaches said lower limit.
Claim 2
Independent Claim
158 words
A method of controlling the idling speed of an engine comprising a main intake passage, a throttle valve arranged in the main intake passage, a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve, a control valve arranged in the bypass passage, and a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage, said method comprising the steps of: detecting a step position of the stepper motor; obtaining the mean value of the step position over a predetermined time; calculating the lower limit of the step position, said lower limit being obtained by subtracting a predetermined step number from said mean value of the step position; and stopping the stepper motor from rotating in a direction wherein the control valve closes when the step position of the stepper motor reaches said lower limit.
Claim 3
Dependent Claim
23 words
A method according to claim 1, further comprising the step of storing said mean value of the step position in a back-up RAM.
Claim 4
Dependent Claim
56 words
A method according to claim 1, wherein the step of obtaining said mean value includes the step of obtaining a mean value of the step position at which the stepper motor is positioned after completion of warm-up of the engine, the stopping of the stepper motor being carried out after completion of warm-up of the engine.
Claim 5
Dependent Claim
32 words
A method according to claim 3, further comprising the step of detecting the completion of warm-up of the engine by a temperature sensor detecting the temperature of a coolant of the engine.
Claim 6
Dependent Claim
42 words
A method according to claim 1, further comprising the step of detecting the idling operating condition of the engine by a throttle switch cooperating with the throttle valve and by a vehicle speed sensor and a neutral switch of an automatic transmission.
Claim 7
Independent Claim
157 words
An apparatus for controlling the idling speed of an engine comprising: a main intake passage; a throttle valve arranged in the main intake passage; a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve; a control valve arranged in the bypass passage; a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage; means for detecting a step position of the stepper motor; and processing means for: obtaining the mean value of the step position over a predetermined time, calculating a lower limit of the step position, said lower limit being obtained by subtracting a predetermined step number from said mean value of the step position, and stopping the stepper motor from rotating in a direction wherein the control valve closes when the step position of the stepper motor reaches said lower limit.
Claim 8
Independent Claim
157 words
An apparatus for controlling the idling speed of an engine comprising: a main intake passage; a throttle valve arranged in the main intake passage; a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve; a control valve arranged in the bypass passage; a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage; means for detecting a step position of the stepper motor; and processing means for: obtaining the mean value of the step position over a predetermined time, calculating a lower limit of the step position, said lower limit being obtained by subtracting a predetermined step number from said mean value of the step position, and stopping the stepper motor from rotating in a direction wherein the control valve closes when the step position of the stepper motor reaches said lower limit.
Claim 9
Dependent Claim
19 words
An apparatus according to claim 6, including a backup RAM for storing the mean value of the step position.
Claim 10
Dependent Claim
54 words
An apparatus according to claim 6, wherein said mean value is obtained by the processing means from a mean value of the step position at which the stepper motor is positioned after completion of warm-up of the engine, the stopping of the stepper motor being carried out after completion of warm-up of the engine.
Claim 11
Dependent Claim
38 words
An apparatus according to claim 8, further comprising a temperature sensor for detecting the temperature of a coolant of the engine, and wherein the processing means determines if the engine is warmed-up in response to said temperature sensor.
Claim 12
Dependent Claim
53 words
An apparatus according to claim 6, further comprising a vehicle speed sensor, an automatic transmission having a neutral switch and a throttle switch cooperating with the throttle valve, the processing means determining if the engine is in the idling operating condition in response to said throttle switch, vehicle speed sensor and neutral switch.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-07-11 | 1987-01-10 | 1987-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-11 | 1991-01-10 | 1991-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-11 | 1995-01-10 | 1995-07-12 | $7700.00 | Window Closed / Lapsed |