Internal-combustion engines – Spark ignition timing control – Electronic control
Reexamination Certificate
1999-06-25
2001-05-22
Kwon, John (Department: 3747)
Internal-combustion engines
Spark ignition timing control
Electronic control
C123S406520
Reexamination Certificate
active
06234147
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ignition timing control device for controlling ignition timing by allowing spark discharge of an ignition plug in an internal combustion engine.
2. Description of Related Art
An ignition timing control device for an internal combustion engine operates to set the ignition timing by allowing spark discharge of an ignition plug at a suitable timing point matched with the operation of an engine. For example, in an acceleration state of an engine in which the rotation of the engine is increased, the control device operates to advance the ignition timing.
However, if the operational state of an engine is shifted from a low rotational state to a rapid acceleration state, the ignition timing tends to more advanced when compared with the ignition timing actually required for the interior of a combustion chamber. This is because of a variation in the air-fuel ratio caused by a rapid change in the throttle valve opening, a variation in the rate of actual rotation of the engine, and the like. Knocking, acceleration shock, and the like may be caused by the above-mentioned conditions.
To solve such problems, Japanese Patent Laid-open No. Hei 1-232169 discloses a method wherein if a variation in opening of a throttle valve of an internal combustion engine is equal to or more than a specific value, it is determined that the operation is a rapid acceleration operation. The ignition timing is therefore retarded, to thereby moderate shock caused by a change in output of the engine upon rapid acceleration.
The above-described prior art method, however, has a problem. Namely, even when the operational state of the engine is shifted from a low rotational state to a rapid acceleration state, if the shifting of the operational state of the engine is performed from an operation in which the throttle valve is gradually opened to an operation in which the throttle valve is rapidly opened, the rotation of the engine increases easily in accordance with an instruction of rapid acceleration. In this case, it is not necessary to retard the ignition timing, and if the ignition timing is retarded in the same manner as when the operational state of the engine is shifted from a state in which the opening of the throttle valve is kept constant to a rapid acceleration state in which the opening of the throttle valve is made to open rapidly, the operational state of the engine is degraded.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an ignition timing control device for an internal combustion engine, which is capable of preventing the occurrence of shock of the engine by suitably controlling the ignition timing upon rapid acceleration of the engine.
According to the present invention, there is provided an ignition timing control device including: a throttle valve opening detecting means for detecting the opening of a throttle valve of an internal combustion engine; an opening retention detecting means for generating an opening retention detecting signal when said means detects that a varied width of the opening of said throttle valve is kept within a specific width for a first specific time or more in a state where the opening of said throttle valve is smaller than a specific low opening; a means for generating a rapid acceleration detecting signal when said means detects that the opening of said throttle valve is increased from said specific low opening to more than a specific high opening for a second specific time or less directly after generation of said opening retention detecting signal; and a retard control means for retarding the ignition timing of said internal combustion engine in response to said rapid acceleration detecting signal.
With this configuration of the ignition timing control device according to the present invention, when the width of the opening of the throttle valve is kept within a specific width for a first specific time or more when the opening of the throttle valve is smaller than a specific low opening and immediately after the above state, the opening of the throttle valve is increased from the specific low opening to more than a specific high opening for a second specific time or less. It is then determined that the internal combustion engine is in a rapid acceleration state. As a result, it is possible to detect a rapid acceleration state of the engine and retard the ignition timing at the time of the rapid acceleration state of the engine thus detected. Therefore, the occurrence of shock of the engine upon rapid acceleration is prevented.
The opening retention detecting means may take a value obtained by adding a specific value to the opening of said throttle valve detected by said throttle valve opening detecting means as an opening upper limit of said specific width. Alternatively, the opening retention detecting means may take a value obtained by subtracting said specific value from said detected opening of said throttle valve as an opening lower limit of said specific width. With this configuration, it is possible to set a suitable varied width of the opening for each detection of the throttle valve opening.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4587938 (1986-05-01), Kobayashi et al.
patent: 4599695 (1986-07-01), Deutsch
patent: 4626997 (1986-12-01), Takeda et al.
patent: 4976240 (1990-12-01), Okuda
patent: 5172666 (1992-12-01), Nonaka
patent: 5222470 (1993-06-01), Oonuma et al.
patent: 5681239 (1997-10-01), Toukura
patent: 1-232169 (1989-09-01), None
Abe Masahiko
Hirakata Yoshiaki
Iwata Yasuo
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Kwon John
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