Internal-combustion engines – Engine speed regulator – Idle speed control
Reexamination Certificate
1999-09-30
2001-03-20
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Engine speed regulator
Idle speed control
C123S352000, C123S361000
Reexamination Certificate
active
06202628
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control apparatus and a control method of an engine, and more particularly, to a control an engine provided, in its intake passage, with a throttle valve which is driven by a throttle valve control device such as a DC motor.
Japanese Patent Application Laid-open No. Hei4-101037 discloses a control apparatus of an engine which realizes engine torque required by a driver (which will be referred to as “required torque” hereinafter). This apparatus calculated the required torque of the driver based on a depressing amount of an accelerator pedal which is the accelerator operating amount. Based on the calculated required torque, a throttle valve opening degree and a fuel injection amount are set, and the required torque is realized using the intake air amount, in accordance with the set throttle valve opening degree, and the set fuel injection amount.
SUMMARY OF THE INVENTION
According to the study of the present inventors, in the case of the conventional control apparatus of the engine, when the driver depresses the accelerator pedal and requires the torque from the idling state in which the throttle valve opening degree is controlled such that the idling does not become unstable due to the operation of the load of an auxiliary equipment, torque shock may be generated, and the engine speed may unintentionally be lowered. Such a phenomenon may cause a sense of incongruity for the driver, and it is not preferable for a quality as goods.
Main factor thereof is that an amount of air required for stabilizing the idling (which will be referred to as “idling required air amount” hereinafter) is not added to the required torque of the driver, i.e., is not synthesized.
This will be explained in more detail with reference to
FIGS. 10A and 10B
which show the relation between the opening area Aa of the throttle valve and the engine torque Te.
First, when the load of the auxiliary equipment is not operated at all at the time of idling, the opening area Aa of the throttle valve is controlled such that the opening area Aa takes the point A in
FIG. 10A
so as to compensate the friction and pumping loss of the engine to keep the idling stably.
On the other hand, the auxiliary equipment load is operated at the time of idling, the opening area Aa of the throttle valve is controlled such that it takes the point A in
FIG. 10B
so as to compensate the contribution by the operation of the auxiliary equipment load to keep the idling stably, in addition to compensation of the friction and the pumping loss of the engine. The point A in
FIG. 10B
has a value greater than the point A in
FIG. 10A
by the engine torque Teal which corresponds to the auxiliary equipment load.
Next, in a state in which the auxiliary equipment load is operated at the time of idling, assume that the accelerator pedal is depressed a little to turn an idle switch OFF, and the opening area Aa of the throttle valve is controlled to be the point D in FIG.
10
A. The point D in
FIG. 10A
has a value greater than the point A in
FIG. 10A
by Te5 which corresponds to the small depression of the accelerator pedal. This engine torque Te5 has a value which is smaller than the engine torque Teal of the point A of FIG.
10
B. Therefore, this means that even though the accelerator pedal is depressed, the engine torque itself is reduced from Teal to Te5.
Since the idle switch is turned OFF and the engine torque is reduced from Teal to Te5 in this manner, the torque shock may be caused or the engine speed may be lowered unintentionally. Further, as the difference between these values is greater, a greater torque shock may be caused or the engine speed may be caused more remarkably.
The present invention has been accomplished in view of these studies, and it is an object of the invention to prevent the torque shock from being generated and to prevent the engine speed from being lowered unintentionally when a driver depresses the acceleration pedal and requires the engine torque in the operation state of the load of the auxiliary equipment at the time of idling, typically.
To achieve the above object, according to the present invention, a required torque of a driver and an idling required air amount are respectively converted into opening area of a throttle valve and then added, and the added value is defined as a target opening area of the throttle valve so that the intake air amount of the engine continues smoothly.
That is, a control apparatus of an engine of the present invention comprises: a throttle valve controller capable of controlling an opening degree of a throttle valve independent from an accelerator; a target torque calculating section calculating a target engine torque using an operation amount of the accelerator; a first opening area calculating section converting the target engine torque into a first opening area of the throttle valve; an idling required air amount calculating section calculating a required air amount at the time of idling; a second opening area calculating section converting the required air amount into a second opening area of the throttle valve; a total opening area calculating section adding the first opening area of the throttle valve and the second opening area of the throttle valve to calculate a target total opening area of the throttle valve; a target opening degree calculating section calculating a target opening degree of the throttle valve in correspondence to the target total opening area; and an output section outputting the target opening degree to the throttle valve controller.
In other words, a control apparatus of an engine of the invention comprises: throttle valve control means for controlling an opening degree of a throttle valve; target torque calculating means for calculating a target engine torque using an operation amount of the accelerator; first opening area calculating means for converting the target engine torque into a first opening area of the throttle valve; idling required air amount calculating means for calculating a required air amount at the time of idling; second opening area calculating means for converting the required air amount into a second opening area of the throttle valve; total opening area calculating means for adding the first opening area of the throttle valve and the second opening area of the throttle valve to calculate a target total opening area of the throttle valve; target opening degree calculating means for calculating a target opening degree of the throttle valve in correspondence to the target total opening area; and output means for outputting the target opening degree to the throttle valve control means.
On the other hand, a control method of an engine of the invention comprises the steps of: calculating a target engine torque using an operation amount of an accelerator; converting the target engine torque into a first opening area of a throttle valve; calculating a required air amount at the time of idling; converting the required air amount into a second opening area of the throttle valve; calculating a target total opening area of the throttle valve by adding the first opening area of the throttle valve and the second opening area of the throttle valve; calculating a target opening degree of the throttle valve in correspondence to the target total opening area; and controlling the throttle valve based on the target opening degree of the throttle valve.
REFERENCES:
patent: 5477826 (1995-12-01), Hara et al.
patent: 5492095 (1996-02-01), Hara et al.
patent: 5706782 (1998-01-01), Kurihara
patent: 4-101037 (1992-04-01), None
Iwano Hiroshi
Kazama Isamu
Ooba Hiraku
Argenbright Tony M.
Foley & Lardner
Nissan Motor Co,. Ltd.
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