JP2548237B2 - Auxiliary air amount control device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary air amount control device for an internal combustion engine of a vehicle with an automatic transmission, and more particularly to an auxiliary air amount control device for an internal combustion engine equipped with an auxiliary air amount control means. (Prior Art) Recently, as the demand for automobiles has become more sophisticated, the drivability of the vehicles also tends to be higher. For example, the engine speed control is one of them, and especially when the accelerator pedal is released, when shifting to idle, and during idle operation, the running state before the idle shift and the operating state of the auxiliary load are taken into consideration. It is necessary to precisely control the engine speed to satisfy drivability and exhaust emission. As a conventional rotational speed control device for this type of internal combustion engine,
For example, ECCS L-type engine 1979 Technical manual 6 1979
The ones listed in Tsuki Nissan Motor Co., Ltd. are known. This device mainly controls the idle speed,
An AAC valve (Auxiliary Air Control Valve) provided in a bypass passage that connects the upstream side and the downstream side of the throttle valve changes the intake air amount during idling to control the idling speed. As the control method, the area (opening) of the bypass passage is changed in an analog manner by the duty-controlled AAC valve to adjust the air flow rate to operate the engine output and match the idle speed to a predetermined target value. I am trying. In such idle control, open control and feedback control are performed. The feedback control is performed when the throttle valve is fully closed, the automatic transmission is in neutral, the vehicle speed is 8 km / h or less, and the difference between the actual engine speed and the target speed is ± 25 rpm or more. On the other hand, the open control of the AAC valve is always performed. For example, at the time of starting, the ON duty value of the AAC valve is set to a basic characteristic value of about 80%,
Further, during traveling, control is performed by adding an acceleration / deceleration correction value (correction value that changes according to the engine speed) to the basic characteristic value. (Problems to be Solved by the Invention) However, in such a conventional technique, the control value of the open control of the AAC valve during traveling is determined only by the engine speed. When the automatic transmission is shifted up by stepping back (that is, the throttle valve is fully closed), the synchronous speed of the automatic transmission does not match the actual engine speed, and the torque “jumps out” (actual engine Sudden acceleration of the vehicle when the rotational speed is higher than the synchronous rotational speed) or "retraction"
(Abrupt deceleration of the vehicle when the actual engine rotation speed is lower than the synchronous rotation speed) occurs, which gives a driver discomfort and deteriorates drivability. (Object of the Invention) Therefore, the present invention aims to harmonize the synchronous speed of the automatic transmission and the actual engine speed during the shift operation of the automatic transmission by depressing the accelerator pedal (that is, fully closing the throttle valve). The purpose is to reduce torque fluctuations when the clutch is engaged and improve drivability. (Means for Solving the Problems) In order to achieve the above-mentioned object, the rotation speed control device for an internal combustion engine according to the present invention detects the speed of a vehicle having an automatic transmission as shown in the basic conceptual diagram of FIG. Vehicle speed detection means a
And a fully closed state detecting means b for detecting that the throttle valve is in a fully closed state, and a gear position which the automatic transmission can assume when it is assumed that the throttle valve is fully closed, and a vehicle speed at that time. A gear position predicting means c for predicting the rotation speed of the internal combustion engine based on the speed of the vehicle and the gear position predicted by the gear position predicting means. The target setting means d for setting the target control value of the auxiliary air amount necessary for achieving the rotational speed, the throttle valve being opened, and the throttle valve for a predetermined period after the throttle valve is actually fully closed. Auxiliary air amount control means e for variably controlling the amount of auxiliary air bypassing the upstream side and the downstream side of the valve according to the target control value,
It is characterized by having. (Operation) In the present invention, before closing the throttle valve, the gear position of the automatic transmission when the throttle valve is actually closed is predicted, and the auxiliary air amount of the internal combustion engine is increased / decreased in consideration of this predicted gear position. To be done. Therefore, for example, when a gear shift operation is performed when the accelerator pedal is released, the synchronous speed of the automatic transmission and the actual engine speed are immediately harmonized, and torque fluctuations at the time of clutch engagement are reduced. (Example) Hereinafter, the present invention will be described with reference to the drawings. 2 to 10 are views showing an embodiment of the present invention. First, the configuration will be described. FIG. 2 is a block diagram showing the overall construction of this embodiment. In this figure, 1 is a sensor group for monitoring various operating conditions of the engine,
The sensor group 1 includes a throttle valve fully closed switch 2, an engine speed sensor 3, a vehicle speed sensor 4, a range selector switch 5, a pattern selection switch 6, a water temperature sensor 7, an air conditioner switch 8 and a battery voltage sensor 9. The throttle valve fully closed switch (fully closed state detecting means) 2 is a so-called idle switch, and outputs an ON signal when the throttle valve is fully closed. The rotation speed sensor 3 outputs a signal in synchronization with the crank angle of the engine, for example, every 1 °, and the control unit 10 described later counts the pulse number of the signal within a predetermined time to obtain the engine rotation speed. A vehicle speed sensor (vehicle speed detecting means) 4 detects a vehicle speed Vsp of a vehicle having an automatic transmission and outputs a signal having a pulse number proportional to the vehicle speed Vsp. The range selector switch 5 detects the selector position of the range of the manual select bar of the automatic transmission, and detects that the current range (for example, "N", "D", "2") is selected. . Pattern selection switch 6
Is a switch for selecting a shift pattern of the automatic transmission and detects which shift pattern (e.g., economy pattern, power pattern, etc.) is currently selected. The shift pattern also includes the presence or absence of an OD (overdrive) prohibition switch. The water temperature sensor 7 is arranged in a cylinder block or the like, and detects the temperature Tw of the cooling water flowing through the water jacket. The air conditioner switch 8 detects the operation of the compressor of the air conditioner and outputs an ON signal when the compressor operates. The battery voltage sensor 9 detects the voltage state of the battery. Signals from various sensors in the sensor group 1 are input to the control unit 10, and the control unit 10 has a function as a gear position predicting unit and a target setting unit, and has a CPU 11, a ROM 12, a RAM 13, and an input / output control circuit 14.
It consists of. The CPU 11 fetches the external data required from the input / output control circuit 14 according to the program written in the ROM 12, and performs arithmetic processing while exchanging data with the RAM 13, and the data processed as necessary. To the input / output control circuit 14. A signal from the sensor group 1 is input to the input / output control circuit 14, and
_A control signal S _A is output from the input / output control circuit 14 to the AAC valve (auxiliary air amount control means) 15. The AAC valve 15 is provided in a bypass passage that connects the upstream side and the downstream side of the throttle valve, and operates the amount of auxiliary air by changing the area (opening) of the bypass passage stepwise based on the control signal S _A. , The engine speed N is controlled by changing the engine output. In addition,
Reference numeral 16 denotes a battery for supplying power to the input / output control circuit 14 and the like. The ROM 12 stores the calculation program in the CPU 11, and the RAM 13 stores the data used for the calculation in the form of a map or the like. Further, a part of the RAM 13 is composed of a non-volatile memory, and retains its stored contents even after the engine is stopped. Next, the operation will be described. FIG. 3 is a flow chart showing the main program of the rotation speed control, and this program is executed once every predetermined period. First, at P ₁ , whether or not the throttle valve is fully closed is determined by the throttle valve fully closed switch 2 (indicated as idle SW in the flow). Depending on whether the throttle valve is fully closed, it is divided into when the accelerator is depressed and when the throttle valve is fully closed. Whether or not the throttle valve is fully closed after a predetermined period (delay time) has elapsed, as will be described later. Divide. Therefore, it can be roughly classified into the following three cases, and these cases will be described below. (I) accelerator operation during running (II) fully closed from the delay time in the (III) after the delay time has elapsed from the fully closed (I) accelerator operation during running First, the throttle valve fully closed switch 2 is ON from OFF when P ₂ delay setting a predetermined value TIME1 the timer tIMER to set (corresponding to delay time) time, predicts the possible gear position of the automatic transmission when the throttle valve at P ₃ is assumed to become fully closed when the To do. This prediction processing is to predict the gear position when the throttle valve is fully closed during normal traveling, and the specific processing content is shown in the subroutine of FIG. In FIG. 4, the range and pattern of the automatic transmission are read based on the outputs of the range selector switch 5 and the pattern selection switch 6 at P ₂₁ , and the shift pattern is selected at P ₂₂ . The range of the range selector switch 5 includes, for example, "D", "2", "N", etc.
The automatic transmission selects the 4th gear according to the running condition,
Holds second gear in "2" range. In the "N" (neutral) range, the gears are in a free state with no meshing. When the range selector switch 5 is set to the "D" range, the pattern selection switch 6 is switched to select a stand pattern (normal traveling pattern) and a power pattern (uphill road, traveling pattern during acceleration). Looking at the stand pattern as an example of these patterns, FIG. 7 shows a shift pattern when shifting up, FIG. 8 shows a shift pattern when shifting down, and FIG. The shift pattern at the time of downshift about a power pattern is shown. In any of the shift patterns, the optimum gear position is automatically selected according to the throttle opening and the vehicle speed. In Figures 7-10 above,
Numbers 1 to 4 represent the gear position of the automatic transmission, respectively 1
Corresponds to 4th gear position. The numbers in the figure indicate the gear positions in the lockup state of the automatic transmission. The solid line in the figure represents the maximum vehicle speed of each gear, and when the speed exceeds these lines or the throttle valve fully open switch is turned on, the gear is shifted up to the next gear. Further, a predetermined hysteresis is provided in the shift pattern during upshifting and downshifting. Similarly, a predetermined hysteresis is provided between the standard pattern (when shifting up and when shifting down) and the power pattern (when shifting up and shifting down). Next, at P ₂₃ , the vehicle speed V _SP is read, and at P ₂₄ , the gear position that the automatic transmission can take when the throttle valve is fully closed is predicted. Specifically, from the shift pattern stored in the ROM 12 of the control unit 10, the vehicle speed at that time,
The gear position is read out and predicted based on the condition that the throttle valve is fully closed. Now, when the gear position is predicted in this way, the program returns to the main program of FIG. 3 again, and at P ₄ , the second target speed N
Calculate _SET2 . The second target speed N _SET2 defines the minimum limit of the target speed during normal running when the throttle valve is not fully closed, and when the throttle valve is fully closed (both non-idle and idle are included. ) Is also the limit value that determines the minimum limit. The process of step P ₄ is specifically executed by the subroutine shown in FIG. In the subroutine shown in FIG. 5, it reads the temperature Tw of the cooling water in the P _31, to look up the second target rotational speed N _SET2 in accordance with the temperature Tw of the cooling water from the predetermined map in P _32. The temperature Tw of the cooling water is the basis for obtaining the target number of revolutions. For example, when the water temperature is low (during warm-up), the air regulator characteristics are corrected, and when the water temperature is high, the cooling effect is improved. Is set to be high. Then P
_{In 33} , it is determined whether the air conditioner switch 6 is ON, and it is turned ON.
If so, compare N _SET2 with the rotation speed N _{A / C} when using the air conditioner on _{page 34} . When N _SET2 <N _{A / C} , in order to maintain the minimum limit of the target speed when using the air conditioner, set N _{A / C} at P ₄₅ as the target speed N _SET2 (N _SET2 = N _{A / C} ) Exit the routine. On the other hand, when the air conditioning switch 6 is OFF at P _33,
Alternatively, when N _SET2 ≧ N _{A / C} in P ₃₄ , it is determined that the minimum limit of the target rotation speed is secured and the routine is ended. Therefore, by executing this routine, the second target rotation speed during normal traveling and during idle
It is possible to set N _SET2 to an appropriate value that is at least above the minimum limit value for stable engine rotation. Return to the main program again, and at P ₅ , the first target speed
Calculate N _SET1 . The first target rotational speed N _SET1 during normal running, in which the throttle valve corresponds to the target rotational speed, assuming that the fully closed, the speed and the predicted gear position of the "vehicle as referred in the claims It corresponds to the rotational speed of the internal combustion engine "(hereinafter, referred to as a fully closed target value)". The process of step P ₅ is also performed by a subroutine and is shown as in FIG. In FIG. 6, the gear position of the automatic transmission predicted in FIG. 4 is read in P ₄₁ , and the gear ratio corresponding to this gear position is read in P ₄₂ . Then P ₄₃
The vehicle speed Vsp is read in and the first target rotation speed N _SET1 is calculated in P ₅₄ according to the following equation. N _SET1 = Gear ratio × k × Vsp ……, where k: Final gear ratio (a constant determined by the tire diameter), and then at P ₄₅ , compare this N _SET1 with the prescribed minimum _limit rotational speed N _LMT as shown in the equation. and, N _SET1 <a lowest limit rotation speed N _LMT the (N _SET1 = N _LMT) of the current process ends the N _SET1 with P ₄₆ for the case of N _LMT maintaining the lowest limit of the target rotational speed, N _SET1 When ≧ N _LMT , it is determined that the minimum _limit has been secured, and the routine ends. N _LMT = N _SET2 + α ...... However, α: constant Therefore, by executing this routine, the target value for full closing is set as N _SET1 even during normal driving. The gear position information will be taken into consideration. Returning to the main program again, at P ₆ , the first target speed is set as the target speed N _SET during normal running (N _SET =
N _SET1 ), the open control value of the AAC valve 15 according to N _SET in P ₇ , that is, the engine speed matches N _SET when the throttle valve is returned and the vehicle coasts. Set the duty control value in the open loop of the AAC valve 15. Then, it is determined whether or not feedback on speed control (F / B) conditions are satisfied at P _8. Since the feedback condition is the same as the conventional one, it is omitted. When the condition for feedback control is satisfied, set the target speed for feedback control in P ₉ , perform feedback correction in P ₁₀ , and send the control signal S _A to the AAC valve 15 in P _11. Output and end this routine. On the other hand, when the feedback condition is not satisfied, P ₉ and P ₁₀ are jumped to P ₁₁ . Thus, during normal running is set open control value of the AAC valve 15 so as to achieve the first target rotational speed N _SET1 when throttle valve is assumed throttle valve is fully closed despite not fully closed It Therefore, the passage area of the passage that bypasses the throttle valve is always open-controlled in advance based on the gear position information when the throttle valve is fully closed, the air flow rate is changed, and the engine output is operated. Even if it is returned to, the engine speed can be immediately controlled to match the automatic transmission. This control is performed in the following cases. (II) in accordance with the YES branch in delay time in the P ₁ from the fully closed, the process proceeds to P _12, the P ₁₂ timer TIM
ER

It is determined whether or not [0] is reached. When TIMER ≠ 0, it is determined that the predetermined delay time has not elapsed, and P ₁₃
Then subtract [1] from the timer TIMER (TIMER = TIMER-
1) interrupting the P _3. Then, when TIMER = 0, it branches from P ₁₂ to P ₁₄ . Therefore, when returning the accelerator pedal during normal driving (when the throttle valve is fully closed), at least within a predetermined delay time it will be continuously performed process P ₃ to P ₁₁ are. In this case, the first target rotation speed N based on the gear position of the automatic transmission before the accelerator pedal is returned.
The opening of the AAC valve 15 is open controlled so that _SET1 can be achieved, and this open control continues to be executed for a while, so even if there is an upshift of the automatic transmission due to the release of the accelerator pedal, the automatic response is automatic. The synchronous speed of the transmission and the actual engine speed are almost the same,
It is possible to significantly improve the drivability of the vehicle by reducing the "protrusion" and "pull-in" of the torque at the time of clutch engagement, which is a current problem. (III) If the YES branch is followed at P ₁₂ after the delay time has passed from the fully closed state, then at P ₁₄ the above step P ₄
The second target speed N _SET2 is calculated by the same processing as in P ₁₅
Then, calculate the target speed N _SET this time according to the following formula. _{N SET = N SET '-ΔN SET} ...... However, N _SET': previous value .DELTA.N _SET: predetermined value previous value N _SET 'Until defined in N _SET = N _SET2 in step P ₁₇ described later It becomes the value based on N _SET1 , and after passing P ₁₇ , it becomes the value based on N _SET2 . By executing the calculation of the formula, the target rotation speed N _SET will gradually decrease. Then
Compare N _SET and N _SET2 with P ₁₆ , and if N _SET <N _SET2 , use P _17
Set N _SET = N _SET2 and proceed to P _{7. If} N _SET ≧ N _{SET 2} , P ₁₇
Jump to P ₇ . In this way, when the predetermined delay time elapses after the throttle valve is fully closed, the target rotation speed N _SET gradually decreases at a rate, and open control or feedback control is performed while at least ensuring the minimum limit N _SET2 . It should be noted that the above three modes are divided for convenience of explanation, but in actual operation, acceleration may be performed from the state of “within delay time from full close” or “after delay time from full close”. is there. Therefore, even if the throttle valve is fully closed, the engine may not reach the idle state,
As in the present embodiment, since the target value at the time of full closing is achieved for at least a predetermined delay time from the full closing of the throttle valve, it goes without saying that the above effects can be obtained from any aspect. is there. (Effect) According to the present invention, before the throttle valve is closed, the gear position of the automatic transmission when the throttle valve is actually closed is predicted, and the predicted air gear position is taken into consideration to determine the auxiliary air amount of the internal combustion engine. Since the increase / decrease operation is performed, for example, during a gear shift operation accompanying the depression of the accelerator pedal, it is possible to immediately harmonize the synchronous speed of the automatic transmission and the actual engine speed, and to reduce torque fluctuations when the clutch is engaged. It can be reduced to improve drivability.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 10 are diagrams showing an embodiment of an auxiliary air amount control device for an internal combustion engine according to the present invention, and FIG. 2 is an overall configuration diagram thereof, and FIG. FIG. 4 is a flow chart showing a main program for controlling the rotation speed, FIG. 4 is a flow chart showing a subroutine for gear position prediction, FIG. 5 is a flow chart showing a subroutine for calculating the second target rotation speed N _SET2, and FIG. Is a flow chart showing a subroutine for calculating the first target rotation speed N _SET1 , FIG. 7 is a shift pattern diagram when the standard pattern of the automatic transmission is shifted up, and FIG. 8 is a standard pattern shift of the automatic transmission. Fig. 9 is a shift pattern diagram at the time of downshift, Fig. 9 is a shift pattern diagram of the power pattern of the automatic transmission at upshift, and Fig. 10 is a power pattern of the automatic transmission. It is a shift pattern diagram at the time of downshift. 2 ... Throttle valve fully closed switch (fully closed state detection means), 4 ... Vehicle speed sensor (vehicle speed detection means), 10 ... Control unit (gear position prediction means, target setting means), 15 ... AAC valve (auxiliary) Air amount control means).

Claims (1)

(57) [Claims] 1. A vehicle speed detecting means for detecting the speed of a vehicle having an automatic transmission; b) a fully closed state detecting means for detecting that the throttle valve is in a fully closed state; and c) the throttle valve is fully closed. Gear position predicting means for predicting a possible gear position of the automatic transmission based on the speed of the vehicle at that time, and d) the speed of the vehicle and the gear position predicting means. Target setting means for calculating the number of revolutions of the internal combustion engine when the throttle valve is fully closed based on the gear position and setting a target control value of the amount of auxiliary air required to achieve the number of revolutions; While the throttle valve is open, and for a predetermined period after the throttle valve is actually fully closed, the auxiliary air amount that bypasses the upstream side and the downstream side of the throttle valve is variably controlled according to the target control value. And an auxiliary air amount control means for controlling the internal combustion engine. Air volume control device.