Internal-combustion engines – Engine speed regulator – Idle speed control
Patent
1997-06-20
1998-04-14
Nelli, Raymond A.
Internal-combustion engines
Engine speed regulator
Idle speed control
F02M 300
Patent
active
057380686
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method and an apparatus for controlling an internal combustion engine for an automotive vehicle. More particularly, the invention relates to a method and apparatus for controlling an internal combustion engine for an automotive vehicle, which can detect driving condition of the internal combustion engine with small fluctuation per vehicle, at high accuracy and low cost.
BACKGROUND ART
Conventionally, in a control apparatus of an internal combustion engine mounted on an automotive vehicle, as sensors for detecting driving condition, such as an intake air flow rate, a coolant temperature, a throttle valve angular position and the like of the internal combustion engine, an air flow sensor, a coolant temperature sensor, a throttle angle sensor and the like are provided, respectively. Outputs of these sensors are input to an input circuit and converted into a digital data by an analog/digital (A/D) converter in the input circuit, and subsequently, arithmetically processed by a microcomputer. On the basis of results of process, actuators, such as a fuel injection device, a spark ignition device and the like are controlled. In a control unit, a reference power source circuit which generates a reference voltage to be supplied to the control unit on the basis of a battery voltage from a battery mounted on the vehicle, that is, a vehiclar battery, is provided.
On the other hand, the reference power source circuit is designed to generate a constant voltage irrespective of fluctuation of the battery voltage. However, the reference voltage generated by the reference power source circuit fluctuates per control units due to fluctuation of values of circuit elements (e.g., resistance value, a value of capacitor and the like) forming the reference power source circuit per the control units. When the reference voltage to be generated by the reference power source circuit fluctuates per control unit, the output values of the sensors and output values of the A/D converter also fluctuate per the control unit. The fluctuation of the output values of the A/D converter due to fluctuation of the circuit elements of the reference power source circuit is about .+-.5%.
On the other hand, due to the fluctuation of the values of the circuit elements forming the A/D converter in the input circuit, the output value of the A/D converter also fluctuates per the control unit. The fluctuation of the output value of the A/D converter due to fluctuation of the circuit elements of the A/D converter is about .+-.0.05%.
An output voltage of the vehicular battery is applied to the A/D converter after voltage division by a divider circuit in the input circuit, to detect an output voltage. In this case, since the values of the circuit elements (e.g. resistor and the like) forming the divider circuit fluctuate per control unit, the output value of the divider circuit also fluctuates per control unit. The fluctuation of the output value of the A/D converter due to fluctuation of the circuit element of the divider circuit is about .+-.1%.
In order to avoid fluctuation of the circuit element, it becomes possible to enhance precision of the values of respective circuit elements by employing a method, such as a laser trimming and the like. In this case, a problem is encountered to rise a cost.
On the other hand, conventionally, an alternator for a vehicle, which is driven and rotated by the internal combustion engine of the automotive vehicle to perform power generating operation, has been controlled typically by a control unit called in general as an IC regulator. The IC regulator controls an output of the alternator at a predetermined level while detecting the voltage of the vehicular battery which is charged by the output of the alternator.
According to JP-B-1-39306 (Publication (1)), there is shown a system in which an amount of current flowing through an exciting coil of the generator is controlled depending upon driving condition by applying a control signal of a microcomputer to a switching mea
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patent: 4903660 (1990-02-01), Sogawa
patent: 5025197 (1991-06-01), Nakamura
patent: 5345908 (1994-09-01), Nishimura et al.
Akagi Yoshihiko
Fujishita Masakatsu
Sasaki Shoji
Shibano Masaru
Hitachi , Ltd.
Hitachi Car Engineering Co. Ltd.
Nelli Raymond A.
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