JPH0660583B2 - Air-fuel ratio controller for engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention provides, for example, an automatic idle control valve provided in a bypass path that bypasses between an upstream side and a downstream side of a throttle valve,
The present invention also relates to an air-fuel ratio control device for an engine having an automatic transmission, so-called torque converter.

(Prior Art) Conventionally, an engine having a self-idle governor (hereinafter simply referred to as SIG) configured to open and close the above-described automatic idle control valve so that the idling speed becomes a target rotational speed is, for example, a special engine. It is described in JP-A-54-76723.

In an engine equipped with the above-mentioned SIG and equipped with an automatic transmission, when the automatic transmission is in a drive range such as a drive range or a reverse range, pull the side brake to bring it into a braking state, and depress the accelerator pedal to perform racing. There was a problem that the engine stopped when returning to the racing.

This point will be described in more detail below. In order to prevent an engine stop from occurring in advance, the above-mentioned SIG does not function outside the idle zone, and the SIG is opened to a predetermined opening degree.

The predetermined opening degree is an opening degree at which engine stop does not occur when the engine speed enters the idle zone due to deceleration.

Further, as shown by the dotted line c in FIG. 4, the above-mentioned SIG function is opened to a predetermined opening to prevent engine stop when decelerating and returning to the idle zone.
The SIG is activated after a predetermined time T2 has elapsed from the deceleration time indicated by.

However, when the engine is idling in the drive range and the reverse range, braking is applied by the side brakes as described above, so the load is applied to the engine, and therefore the target rotation speed becomes high.

Therefore, the SIG increases the opening and increases the filling amount to increase the target rotation speed. On the other hand, since the rotation of the engine is further stabilized when the filling amount is increased in this way, the air-fuel ratio is made lean and the ignition advance is advanced to improve fuel efficiency.

By the way, when the racing return is performed with the drive cash register or reverse range as described above, the engine is under load in this state, so the engine speed drops quickly and engine stop easily occurs. In the idle zone of the reverse range and the reverse range, the ignition advance is advanced to the optimum value, so it is not preferable to control the ignition timing to prevent the engine stop.

(Object of the Invention) This invention focuses on the fact that the air-fuel ratio of the engine intake air becomes lean when the automatic transmission is in the drive range, and the engine speed during idling return rotation during racing return in the drive range. It is an object of the present invention to provide an engine air-fuel ratio control device capable of increasing the torque and preventing the engine stop at the time of the above-mentioned racing return when the air-fuel ratio is controlled to be rich when the number reaches a certain number.

(Structure of the Invention) In the present invention, in an air-fuel ratio control device for an engine equipped with an automatic transmission, a shift detecting means for detecting a state where the engine speed shifts to an idle zone, and a shift range of the automatic transmission are detected. A shift range detecting means, and a first control means for receiving the output of the shift range detecting means and increasing the intake air amount, leaning the air-fuel ratio, and advancing the ignition timing when the shift range is selected as the drive range; When the shift of the idle zone is detected in the state where the shift range is selected to the drive range by receiving the outputs of both the above-mentioned detection means, the air-fuel ratio is made richer than the air-fuel ratio in the normal idle state only for a certain period of time after the detection. The air-fuel ratio control device for an engine is provided with a second control means for controlling.

(Effect of the Invention) According to the present invention, the above-mentioned shift detecting means detects the state where the engine speed shifts to the idle zone, and the above-mentioned shift range detecting means detects the shift range of the automatic transmission,
In response to the output of the shift range detecting means, the first control means increases the intake air amount, leans the air-fuel ratio, and advances the ignition timing when the shift range is selected as the drive range. Moreover, when the automatic transmission is detected to return to the idling return rotational speed when the automatic transmission is returned to the racing range in the drive range such as the drive range and the reverse range by the both detecting means, the second control described above is performed. The means operates to control the air-fuel ratio to be rich relative to the air-fuel ratio in the normal idle state only for a certain period. Therefore, the torque is increased, and there is an effect that the engine stop at the time of the above-mentioned racing return can be prevented.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows an air-fuel ratio control device for a vehicle engine with an automatic transmission. In FIG. 1, a piston 3 is arranged in a cylinder 2 of the engine 1, and the piston 3 and the crank 4 are connected by a connecting rod 5. is doing.

Further, an ignition plug 7 is exposed in the combustion chamber 6, and the intake port 8 communicating with the combustion chamber 6 is connected to the intake port 8.
Is provided with an intake valve 9 for opening and closing, and an exhaust valve 11 for opening and closing the exhaust port 10 is provided at an exhaust port 10 communicating with the combustion chamber 6 described above.

Further, an air flow meter 14, a throttle valve 15, and a combustion injection valve 16 are provided in an intake passage 13 extending from the air cleaner 12 to the intake port 8, and the air flow sensor 17 is provided in the air flow meter 14 described above.
Further, a throttle opening sensor 18 is connected to the throttle valve 15 described above.

Further, a bypass path 19 that bypasses between the upstream side and the downstream side of the above-mentioned throttle valve 15 is provided, and an automatic idle control valve 20 is provided in this bypass path 19.

By the way, the CPU 30 controls the fuel injection valve 16 and the automatic idle control valve 2 according to the program stored in the ROM 31.
0, the shift determination circuit 21 and the zone determination circuit 22 are driven and controlled, and the RAM 32 requires the information of the storage table shown in FIG. 2 and the idle return rotation speed Ns shown in FIG. 4 and the target rotation speed Nt at idle. Memorize various data.

Further, the above-mentioned CPU 30 is provided with an automatic transmission select /
A sensing signal from a drive range sensor (hereinafter simply referred to as a D range sensor) 33 that detects that the lever is in a state indicating the D (drive) stage of normal traveling, and the above-described select lever is in the R (reverse) stage. Sensing signal from a reverse range sensor (hereinafter simply referred to as R range sensor) 34 for detecting
The air flow sensor signal U corresponding to the volumetric flow rate of the intake air from, the throttle opening TVO from the throttle opening sensor 18, and the engine speed Ne are input.

The engine speed Ne described above can be obtained, for example, by converting the signal every 1 degree by a frequency-voltage converter.

In this embodiment, the CPU 30 performs the detection that the engine speed Ne has entered the idle zone and the rich control of the air-fuel ratio based on the detected output.

That is, the above-mentioned CPU 30 has the shift range detecting means 42.
When the shift range is selected to the drive range in response to the output of (see FIG. 3), the intake air amount is increased, the air-fuel ratio is lean, and the ignition timing is advanced. (See FIG. 3) and the shift range detecting means 42 (see FIG. 3), the idle zone A (see FIG. 2) in a state where the shift range is selected as the drive range by receiving the outputs of both detecting means 44, 42. ) Is detected at time t2 (see FIG. 4), the second control means for controlling the air-fuel ratio to be richer than the air-fuel ratio in the normal idle state only for a fixed time T1 (see FIG. 4) from the time t2 when the shift is detected. (See steps 45 and 46 of the flowchart shown in FIG. 3).

The operation of the engine air-fuel ratio control device thus configured will be described with reference to the flowchart of FIG.

In the first step 41, the CPU 30 drives the shift determination circuit 21 that determines the position of the select lever of the automatic transmission, and in the next second step 42, the CPU 30 currently operates based on the output of the shift determination circuit 21 described above. Whether the select lever of is in the drive range (hereinafter simply referred to as D range) or reverse range (hereinafter simply referred to as R range), that is, whether the shift position of the automatic transmission is within the drive range is determined. However, when it is determined that the range other than the D range and the R range is, for example, the parking range (P range) and the neutral range (N range), the process ends.

On the other hand, there is a sensing signal from the D range sensor 33 or the R range sensor 34 described above, and the CPU 3 determines that the D range or the R range is determined in the second step 42 described above.
If 0 is determined, in the next third step 43, the CPU
30 drives the zone determination circuit 22.

When the zone determination circuit 22 is driven, the engine speed Ne and the throttle opening TVO are input to the CPU 30.

Next, in a fourth step 44, the CPU 30 determines whether or not the engine speed Ne has returned to the idle zone A by being decelerated in sequence based on the storage table shown in FIG.

That is, the current engine speed Ne is compared with the preset idle return speed Ns (see fourth), and Ne =
When it is determined that it is the instant at which the idle zone is returned in Ns, the process proceeds to the next fifth step 45.

In the fifth step 45, the CPU 30 calculates the air-fuel ratio correction amount that becomes richer than the air-fuel ratio in the normal idle state shown in FIG. 4, and in the next sixth step 46, the CPU 30 sets the above-mentioned air-fuel ratio correction amount. Accordingly, for example, the fuel injection valve 16 is controlled so as to perform the fuel increase correction, and the output control of the fuel injection valve 16 according to the above-described fuel increase correction is performed only for a predetermined time T1 preset by the CPU built-in timer.

Further, in the above-described fourth step 44, the CPU 30 causes Ne <
When it is determined to be Ns, in the next seventh step 47, CP
U30 determines whether the engine speed Ne is in the idle zone A, and when determining that it is in the idle zone A, moves to the above-mentioned fifth step 45 and determines that it is outside the idle zone A. If so, the process ends.

It is needless to say that the SIG operation is performed by the automatic idle control valve 20 described above after the elapse of the above-described fixed time T1, and the engine speed Ne during idling is controlled to the target speed Nt. In short, the shift position of the automatic transmission decelerates the engine in the drive range (see time t1 in FIG. 4), and the engine speed Ne is the same time t2.
When the idling return speed Ns set in advance is reached by the CPU 30, this is detected by the CPU 30, and C is detected based on this output.
The above-mentioned CP only for a certain time T1 set by the PU built-in timer
Since U30 controls the air-fuel ratio to rich as shown by the characteristic a in FIG. 4, the engine speed Ne decreases less as shown by the characteristic b in the same figure, and the torque rises. As a result, there is an effect that it is possible to prevent an engine stop at the time of returning the racing under the above conditions.

In the correspondence between the configuration of the present invention and the above-described embodiment, the shift detecting means of the present invention corresponds to the fourth step 44 under the control of the CPU 30 of the embodiment, and similarly, the shift range detecting means under the control of the CPU 30. The second control means corresponds to the second step 42, the first control means corresponds to the CPU 30 itself, and the second control means corresponds to the fifth step 45 and the sixth step 46 under the control of the CPU 30. It is not limited to the configuration of the embodiment.

For example, the drive range may be a drive range, a reverse range, or a range such as 1st speed or 2nd speed.

[Brief description of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is a system diagram showing an air-fuel ratio control device for an engine for a vehicle with an automatic transmission, FIG. 2 is an explanatory view of a storage table, and FIG. 3 is air-fuel ratio control. A flow chart shown in FIG. 4 is a time chart showing rich control of the air-fuel ratio. 30 ... 1st control means 42 ... 2nd step (shift range detection means) 44 ... 4th step (shift detection means) 45, 46 ... 2nd control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Aki Tamura Inventor Aki-gun, Hiroshima Prefecture Aichi-gun, Shinchi No. 3-1-1 Mazda Co., Ltd. (56) References JP 61-149556 (JP, A) JP 57- 163138 (JP, A) JP 58-206842 (JP, A) JP 58-25524 (JP, A)

Claims (1)

[Claims] 1. An air-fuel ratio control system for an engine equipped with an automatic transmission, wherein a shift detection means (44) for detecting a state where the engine speed (Ne) shifts to an idle zone (A), and an automatic transmission. A shift range detecting means (42) for detecting a shift range and an output of the shift range detecting means (42), when the shift range is selected as a drive range, the intake air amount is increased, the air-fuel ratio is lean, and When the shift to the idle zone (A) is detected while the shift range is selected to the drive range by receiving the outputs of the first control means for advancing the ignition timing and the detection means (44, 42). (T2), the second control means (4) for controlling the air-fuel ratio to be richer than the air-fuel ratio in the normal idle state only for a certain time (T1) from the time of detection (t2).
5, 46) and an air-fuel ratio control device for the engine.