JPH04112943A - Controller for engine - Google Patents

Abstract

PURPOSE:To prevent the abrupt starting feeling of a vehicle at the time of brake release in a driving range by reducing an aimed rotational number of idling by a preset rotational number when it is detected that the shifted position of an automatic transmission is in the driving range and that a brake is in a non-operational state. CONSTITUTION:A bypass suction route 7 is provided on a throttle chamber 3 bypassing a throttle valve 6, and an electromagnetic valve 8 for controlling engine rotational number at the time of idling is provided on the route 7. The electromagnetic valve 8 is opened/closed through an electromagnetic valve control signal of a preset duty ratio correspondent to the rotational deflection between an aimed rotational number and an actual rotational number, by an engine control unit (ECU) 9. The aimed rotational number is set in such a way that it is higher than normal when an engine outside load, such as air- conditioner is input. In this case, a change-speed range of an automatic transmission 2 is in the position of a driving range, and when a braking is released at a time that a creep running is possible, the aimed rotational number set higher by the input of the engine outside load is re-set lower by a preset rotational number.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device that controls the engine speed during idling to a predetermined target speed.

(Prior Art) Engine idle speed control devices based on electronic control methods, which have recently come to be widely used in automobile engines, are, for example, intake air amount control systems based on electronically controlled fuel injection. An intake air bypass passage is formed to bypass the throttle valve of the engine, and an intake air amount adjusting means (idle rotation An electromagnetic throttle valve for number control or a plurality of ○N10 F type air bypass valves) is installed to detect the actual engine speed detected by an engine speed detection means such as an RPM sensor and a preset idle target. The engine is configured to operate at the predetermined idle target rotation speed by feedback controlling the intake air jl adjustment means or the air bypass valve by means of a feedback control means in accordance with the amount of deviation between the rotation speed and the rotation speed.

And in the above case, more specifically the engine core generally constituted by a micro-processor) the above-mentioned feeder using a roll unit.

The intake air amount adjusting means is controlled by a predetermined basic control amount set corresponding to the predetermined idle target rotation speed, and the actual rotation of the ennon obtained by the predetermined basic control amount is controlled. If the number does not match the idle target rotation speed, the predetermined basic control amount is corrected (increased or decreased) according to the rotational deviation amount and load amount (engine external load amount such as air conditioner) at that time. A configuration is employed in which the actual rotational speed of the engine is converged to the predetermined idle target rotational speed (see, for example, Japanese Patent Laid-Open No. 1-20036).

The final intake air amount control amount G including the external load correction amount during the idle speed control is determined as follows.

Final control jll G = G B + ΣG L + G
rB... (1) However, GB, basic control amount GL, load correction amount G corresponding to various external engine loads such as air conditioner, power steering link, etc. Generally, ゎ is a reference control amount that is set corresponding to the cooling water temperature value of the engine/engine based on the characteristic value of the engine plaster when the engine is under no load and without deterioration. The load correction amount GL corresponding to an external load (for example, air conditioner ON, power steering ON, etc.) is a control amount determined as the sum of load specific values corresponding to each load amount, and uniformity of the intake air amount in load correction mode. Further, the feedback correction amount GFB is determined according to the amount of deviation between the actual engine speed detected by the engine speed detection means and the preset idle target speed. This is a correction amount during closed-loop control that is arbitrarily determined according to changes in the operating state.

That is, as is clear from the above general formula (which is a formula for calculating the duty ratio of the control signal that drives and controls the solenoid of the intake air amount adjusting means described above), the final control amount G is determined by the engine-specific characteristics. The above-mentioned basic control amount G, which is determined by the engine speed and cooling water temperature, is the center, and the correction amount GL corresponding to the external load amount and the feedback correction amount G and FB corresponding to the deviation amount of rotation speed are added and determined. It has become.

Of course, the feedback correction amount arm acts on an area where feed bank control can be performed (hereinafter simply referred to as the F/B wi area), and normally the F/B area is when the idle contact is ON ( throttle fully closed)
and below a predetermined reference rotation speed for idle rotation speed control (this, of course, is determined according to the characteristics of the engine in the same way as the idle rotation speed, but is usually set a predetermined value higher than the idle rotation speed). Decrease is determined based on two conditions.

On the other hand, in this way, when an external engine load such as an air conditioner is applied, the amount of intake air is increased in accordance with the amount of load, and idle stability is ensured, but at the same time, idle stability is The target idle speed itself is set higher by a predetermined amount in order to improve the performance of the air conditioner, especially when the vehicle is stopped.

(Invention or problem to be solved) However, such external loads on the engine such as air conditioners
In the case of an engine idle speed control device that employs an upward change control means for the idle target speed by N, for example, a vehicle equipped with a torque converter type automatic transmission (hereinafter referred to as an A/T)
When applied to automobiles), the following problems arise.

That is, in the case of the A/T vehicle, when the shift lever of the transmission is generally shifted to the drive range (D), even though the accelerator is not operated and the engine is in an idling state, If the brake is not pressed or operated, there is a so-called creep phenomenon in which the vehicle starts running at a predetermined low speed (generally about 4 km/h). This creep phenomenon is caused by the drive range (D)
Unlike the neutral range (N), the engine and torque converter drive system are originally connected, so torque is transmitted according to the idling speed at that time, which drives the vehicle. This is due to a number of reasons. Therefore, if the target idle speed itself is set high due to the external engine load being turned on as described above, the transmitted torque itself will eventually become large.

For this reason, there is a problem in that, for example, when the vehicle moves from a stopped state where the brake is depressed to a brake released state, a relatively large transient feeling of the vehicle jumping out occurs even though the accelerator is not depressed.

In general, the amount of load on the engine in the drive range (D) where the creep phenomenon may occur is determined by the amount of load applied to the engine in the drive range (D) when the brake pedal is stepped on,
Or when the vehicle is stopped with the handbrake pulled (brake switch is ON), or when the brakes are released as described above and the vehicle can start creeping ( Brake switch?
The situation is quite different in the case of FF state). In other words, at the start of creep running, the relative rotational speed of the torque transmitting section of the torque converter decreases, frictional resistance decreases, and rotational stability increases. As a result, the load is reduced, so the target idle speed does not have to be as high as it normally would be during brake operation.

(Means for Solving the Problem) The present invention has been made for the purpose of solving the above problems, and includes an engine rotation speed detection means for detecting the engine rotation speed during idling, and the engine rotation speed. The actual engine speed is adjusted to the idle target by feedback controlling the intake air amount of the engine according to the deviation between the actual engine speed detected by the detection means and a preset predetermined idle target speed. In the engine equipped in a vehicle having an automatic transmission, the engine is equipped with feedback control means for converging to the rotation speed, and idle target rotation speed control means for increasing the idle target rotation speed when an external load is applied to the engine. drive range detection means for detecting that the shift position of the transmission is in the drive range; brake operation state detection means for detecting whether the brakes of the vehicle are activated or not;
When the drive range detecting means detects that the / foot position of the automatic transmission is in the drive range, when the brake operating state detecting means detects that the brake is not in operation, it is compared to when the brake is in the operating state. The invention is characterized in that it further comprises idle target rotation speed variable means for lowering the idle target rotation speed controlled by the idle target rotation speed control means by a predetermined rotation speed.

(Function) With the configuration of the engine control device of the present invention described above, even when the idle target rotation speed is set higher than normal due to application of an external load to the engine such as an air conditioner, the automatic transmission does not change gears. When the range is in the drive range position and the brake is released in a state where creep driving is possible, the idle target speed, which was set high due to the application of the external engine load, is reset to a predetermined low speed, thereby stabilizing the idle. It works to suppress the feeling of the vehicle jumping out when the brakes are released on a dry plane to the minimum possible while ensuring safety.

(Effects of the Invention) Therefore, according to the engine control device of the present invention, it is possible to easily achieve both functions of ensuring idling stability when an external load is applied to the engine and preventing the vehicle from jumping out when the brake is released in the drive range. can be done.

(Example) First, FIGS. 1 and 2 show an idle speed control device for an automobile gasoline engine having an automatic transmission equipped with a torque converter, in which the present invention is applied. Fig. 1 is a schematic diagram of the idle speed control system of the embodiment device, and Fig. 2 is a schematic diagram of the engine control unit (7) in the control system.
) is a flowchart showing idle target rotational speed variable control operation according to FR+operation state.

First, an outline of the idle speed control system according to an embodiment of the present invention will be explained with reference to FIG. 1, and then the control operation of the main parts will be explained.

In FIG. 1, reference numeral 1 is the engine body, and intake air is taken in from the outside via an air cleaner 30.
Thereafter, the air is supplied to each cylinder via an air flow meter 2 and a throttle chamber 3.

Further, fuel is supplied from the fuel tank 12 to the engine side by the fuel pump 13, and is injected synchronously or asynchronously by the fuel injector 5 according to the measured value Q of the air 70 meter 2. The amount of air taken into the cylinder during normal running, excluding idle and creep running states as will be described later, is controlled by a throttle valve 6 provided in the throttle chamber 3. The Freutl valve 6 is operated in accordance with the opening degree of the accelerator pedal.

Note that the throttle chamber 3 is provided with a bypass intake passage 7 that bypasses the throttle valve 6, and the bypass intake passage 7 includes an intake air amount adjusting means for controlling the engine speed during idling. A current-controlled solenoid valve (so-called ISC valve) 8 is provided. This solenoid valve 81L? The engine control unit described above determines that the operating state of the engine is in the idle feedback control region, and correspondingly sets a predetermined duty ratio according to the rotational deviation between the target rotational speed and the actual rotational speed at that time. When the solenoid valve control signal G is applied, or during steady operation, the solenoid valve control signal for dashpot air supply is applied in the deceleration region where the flow valve is fully closed from a high rotation state of more than a predetermined value. The valve is opened according to the duty ratio of each control signal when the control signal is activated, and is completely closed at other times.

Further, reference numeral 10 indicates an exhaust pipe of an engine equipped with a three-way catalytic converter 11 for purifying exhaust gas.

On the other hand, the reference numeral 14 indicates the cylinder 61 of the engine main body 1.
A spark plug provided in one part, the spark plug 14
A predetermined ignition voltage is applied to the igniter 18 via a distributor 17 and an igniter 18, and the application timing of this ignition voltage, that is, the ignition timing is controlled by the engine control unit (hereinafter referred to as ECU) 9 to the igniter 18. Ignition timing control signal 1 supplied to
Huntrolled by gt. Moreover, the code 19 is
This sensor is provided in the cylinder block portion of the engine main body 1, and outputs a voltage output V0 corresponding to the intensity of the engine's 7-stroke occurrence, and inputs it to the ECU 9. Furthermore, the reference numeral 20 is a boost pressure sensor 20,
An engine boost pressure B corresponding to the engine load is detected and input to the ECU 9.

The ECU 9 is centered around a microcomputer (CPU) which is, for example, a calculation unit, and includes a feedback control circuit for the amount of intake air using the solenoid valve 8 during idling, a memory (ROM), and an interface (I).
lo) It is configured with a circuit, etc. In addition to the above-mentioned detection signals, the interface circuit of this ECU 9 also receives, for example, an engine start signal (ECu trigger) from a starter switch (not shown), an engine rotation speed detection signal Ne from an engine rotation speed sensor 15, and a water temperature thermistor 16. Detection signal T-1 of engine cooling water temperature detected by, for example, throttle opening detection signal TV○ detected by throttle opening sensor 4, intake air amount detection signal Q detected by air flow meter 2, etc. of the engine. Various detection signals necessary for controlling the operating state (rotation speed) are inputted.

Note that the reference numeral 50 indicates an intake temperature sensor.

The control value (G, , ) for controlling the amount of intake air during the feed bank control operation by the feedback control circuit of the ECU 9 is, for example, a preset target idle speed NO and the engine speed sensor 15. Deviation from the actual engine speed Ne detected by ±Δ
It is configured as an integral value that changes in the positive or negative direction depending on the magnitude of Ne (±ΔNe=Ne-NO), and the solenoid valve 8 opens in response to the integral value corresponding to the rotational deviation amount ΔNe. The intake air flow rate of the bypass intake passage 7 is controlled to increase or decrease. Then, the intake air amount corrected for increase/decrease moves the bypass intake passage 7 to >TJ
L is supplied to the engine. In this case, the ECU 9 switches the foot brake switch SW, the side brake SW, and , is turned OFF and creep running is possible, the aim is to limit the feed control 11Ga8 or reduce the oven loop value by varying (reducing) the idle target rotation speed No. as shown in the flowchart in Fig. 2. perform control operations.

On the other hand, reference numeral 2 indicates an automatic transmission, for example, an o'y Quanob torque converter type automatic transmission with an overdriving mechanism, which is connected to the output shaft of the engine body 1. The automatic transmission 21 includes, for example, a lock-up clutch 22, a lock-up control valve 23, and a lock-up solenoid 24.
, a lock-up mechanism consisting of Ronoqua knob control 22, 30, etc., an overdriving gear 27, an overdriving valve 28, an overdrive/gusole/
an overdriving mechanism consisting of an id 34, an Oha driving switch 35, etc., a gear train section 26 of the transmission itself, and a centrifugal governor 29 for rotation speed detection provided on the transmission output shaft side via the gear train section 26. and the lock-up control valve 23, overdriving gear 27, overdriving valve 28, and gear train section 2.
6, etc., a cow pull-down solenoid 32, a kick-down switch 33, etc.

Then, the lock-up control unit 30 determines whether overdrive or lock-up is OK based on input signals from various sensors, and if each condition is satisfied, the kick-down solenoid 32
, controls the lock-up control valve 23, overdriving gear 27, overdriving valve 28, gear train section 26, etc. to be operable via the control valve 31, and also supplies a lock-up signal SL to the lock-up solenoid 24 to lock the lock-up mechanism. The up clutch 22 is operated to lock up the torque converter.

The lock-up signal SL is sent to the ECU 9 as necessary.
is input.

Further, reference numeral 41 is an inhibitor switch installed on a shift lever part 40 of the automatic transmission 21, which detects the operation position (at least N or D) of the shift lever 42 of the automatic transmission 21. The detection signal is sent to the above ECU.
Enter 9.

Further, the reference numeral 45 indicates the foot brake of the vehicle, and the reference numeral 45 indicates the foot brake of the vehicle.
W1 is a foot brake switch provided corresponding to the foot brake 45, which turns ON1 when the foot brake 45 is stepped on, and turns OFF when the foot brake 45 is released;
Input the N or FF signal to the ECU 9. Also, the reference numeral 47 is a handbrake of the vehicle, and the handbrake 47 also includes a handbrake switch Sw,
is provided, and the operation of the handbrake 47 (O
N or 0FF) state is detected and the above EC1J9 is turned on,
Supply OFF signal. Furthermore, the code 5j is the air conditioner (hereinafter referred to as the air conditioner) humbronosa, and its ○N/○FF signal is the above-mentioned ECL! 9 is input.

Next, the engine control unit 9 performs variable (reduction) control of the idle target rotation speed when the transmission is shifted to drive range D and the brake is released from a state in which the vehicle is stopped by braking. The operation will be explained in detail with reference to the flowchart shown in FIG.

First, in step S, the current engine speed Ne,
ON/OFF signal of idle contact 5WXD, 0N10FF signal of Humbrenosa 51, shift range position of automatic transmission, braking state (foot brake switch SW)
3. The detected values of the engine and vehicle conditions such as the handbrake switch SW (○N-0FF) are input in sequence, and the current engine operating condition is used to control the solenoid valve 8 of the bypass intake passage 7 through feedback control. After confirming whether or not the intake air amount is in the idle operation region where the intake air amount should be corrected to increase or decrease, that is, the idle feedback control region (hereinafter abbreviated as ID-FB region), proceed to Step S and adjust the air conditioner. Jonar's Comple)
l + 51 Determine whether or not the engine is ON (operating state driven by Ennon).

If the result is YES, it is further determined in step Ss whether or not the shift range of the automatic transmission is dry plane:, '(D), and the determination result is YES (drive range D).
), the process further proceeds to step S4, where it is sequentially determined whether the foot brake 45 and the hand brake 47 are ON.

As a result, all three judgment results in steps S and ~S4 are YES, that is, the engine external loads such as compressor and su51 are applied, and the idle target rotation speed NO is lower than the normal value NO' for the purpose of increasing the air conditioner capacity. When the vehicle is stopped, the automatic transmission is in the shift position 127 or the drive range (D), and the foot brake 45 or handbrake 47 is operated, as described above. As the load may be large, and there is no need to prevent the vehicle from flying out, we proceed to step S, which increases the capacity of external loads such as air conditioners and activates them as intended. Priority is given to ensuring sufficient idle stability, and the target idle rotation speed N o =NA is set higher than in the normal state. As a result, the amount of intake air increased by the feedback control is increased, the capacity for external loads such as air conditioners is improved, and stable idle rotation can be maintained despite the operation of the external loads. On the other hand, the above step S.

If the two determination results of S, are YES and the other determination result of step S4 is NO, that is, the above Rouchia C8, ~
S, ), an external engine load such as Humbrefusa 51 is applied, and the target idle speed No. is set higher than normal (No = N A), and the automatic transmission is currently in the drive range position. Even if the vehicle is in the range (D), if the foot brake 45 or the hand brake 47 is released and the vehicle is in a state where the vehicle can creep,
The engine and the torque converter drive system are connected, and as mentioned earlier, the load can be reduced to the extent that the target idle speed No.
If it is high, the vehicle will feel like it is jumping out, so proceed to step S and set the idle target rotation speed as low as possible within the range that can maintain the idle stability due to the engine external load operation such as the air conditioner. No-N
s is changed (reduced) to minimize the feeling of the vehicle jumping out.

A time chart of the idle target rotation speed variable operation during this period is shown in FIG. 3.

As a result, according to the engine control device of the embodiment of the present invention, it is possible to maintain the load capacity amplifier when an external load such as an air conditioner is applied to the engine, and to maintain idle stability corresponding to an increase in the load amount of the external load. This makes it possible to prevent the feeling of the vehicle jumping out when the vehicle is moving.

In the above embodiment, as shown in FIG. 1, the intake air amount adjusting means during idling operates continuously from fully open to fully open according to the duty ratio of the current applied to the single bypass intake passage 7. Current control allows precise opening control! ! ! Although a solenoid valve (so-called ISC valve) 8 is adopted, as the intake air amount adjusting means, for example, a plurality of bypass intake passages with different passage diameters are arranged in parallel according to the type of load applied, and the bypass Each of the intake passages has an ON10F valve that opens in conjunction with the application of the corresponding external load.
It goes without saying that a simple type equipped with an F-type electromagnetic on-off valve may be used.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a control system diagram of an engine idle speed control device according to an embodiment of the present invention, and FIG. 2 C is a variable idle target speed control of an engine control unit in the same control device. The flowchart of FIG. 3 showing the operation is a time chart of the main part corresponding to the control operation of FIG. 2. ] Yu/Red Ennon body 2 Air flow meter 6 Throttle valve 7 Bypass intake passage 8 Solenoid valve 9 En/fu Control 22, Torl 5 ・ 21 ・ 40 ・ 45 ・ 47 ・ 5] ・W1 SW Exit Driver・Engine speed sensor・Automatic transmission scratches/Full lever part・Foot brake・Handbrake・Fun brake・Foot brake switch/hand brake Suinochi Ma Tsuta Co., Ltd. agent

Claims (1)

[Claims] 1. An engine rotation speed detection means for detecting the engine rotation speed at idle, and a method according to the deviation between the actual engine rotation speed detected by the engine rotation speed detection means and a predetermined idle target rotation speed. Feedback control means for converging the actual rotation speed of the engine to the target idle rotation speed by feedback controlling the intake air amount of the engine; and a target idle rotation speed for increasing the target idle rotation speed when an external load is applied to the engine. In an engine mounted in a vehicle having an automatic transmission, the engine includes a drive range detection means for detecting that the shift position of the automatic transmission is in a drive range, and a drive range detection means for detecting that the shift position of the automatic transmission is in a drive range, In a state in which the shift position of the automatic transmission is detected to be in the drive range by the brake operation state detection means for detecting operation and the drive range detection means, the brake operation state detection means detects a non-operation state of the brake. and idle target rotation speed variable means for lowering the idle target rotation speed controlled by the idle target rotation speed control means by a predetermined number of rotations compared to when the brake is activated. .