JP2012117407A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress fluctuation and shock of engine rotation speed when performing an N control of an automatic transmission.SOLUTION: This control device of an internal combustion engine executes the N control to slide a clutch by opening hydraulic pressure to be supplied to the clutch for disconnecting and switching a turbine runner of a torque converter and an axle by prescribed amount when a vehicle is stopped in a state in which a shift position is in a travel range, detects a difference between the engine rotation speed and the rotation speed of the turbine runner after starting the N control, and performs processing to reduce an engine output on condition that the rotation speed difference becomes less than a prescribed value.

Description

  The present invention relates to a control device for an internal combustion engine accompanied by an automatic transmission.

  Recent automobiles are often AT cars equipped with automatic transmissions. As an automatic transmission for a vehicle, a continuously variable transmission including a torque converter and a belt-type continuously variable transmission mechanism is known (for example, refer to the following patent document).

  A clutch capable of switching connection and disconnection is interposed between the turbine runner of the torque converter and the axle. In the above-mentioned continuously variable transmission, this corresponds to a forward / reverse switching device using a planetary gear mechanism that is interposed between the torque converter and the belt type CVT.

  Generally, the clutch is in a connected state in a travel range (D range or R range), and is in a disconnected state in a non-travel range (N range or P range). If the shift position is stopped in the travel range, the turbine runner of the torque converter is constrained by the axle, thereby increasing the fluid resistance against the pump impeller and deteriorating the fuel consumption of the engine that rotationally drives the pump impeller.

  Therefore, when the vehicle stops in the travel range, so-called N control is performed in which a predetermined amount of hydraulic pressure supplied to the clutch is released and the clutch is slid. With this N control, it is possible to secure creep force while the vehicle is stopped and improve the responsiveness to re-start while suppressing deterioration of fuel consumption.

  When performing the N control, it is necessary to prevent the engine speed from blowing up due to the clutch slipping out. For this purpose, after a predetermined delay time has elapsed since the opening of the valve and the release of the hydraulic pressure supplied to the clutch has started, a process for suppressing engine output (reduction correction of intake air amount and fuel injection amount, ignition timing Execute retard correction, etc.).

  However, the time required until the hydraulic pressure supplied to the clutch is released by a predetermined amount varies depending on the viscosity of the hydraulic oil. Therefore, it is not easy to synchronize the timing at which the clutch starts to slide and the timing at which the engine output is suppressed, and sometimes the timing is shifted and the engine speed may fluctuate.

  A similar problem occurs when the N control is terminated and the normal control is started. This is because the time required to supply the hydraulic pressure again to the clutch and complete the clutch in order to end the N control also varies depending on the viscosity of the hydraulic oil. In other words, the timing at which the clutch is engaged without slipping deviates from the timing at which the suppressed engine output is recovered, and the engine speed may also fluctuate.

JP 2010-230097 A

  An object of the present invention is to suppress fluctuations in engine speed and shocks when shifting to N control and / or when returning from N control.

  In the present invention, when the vehicle stops with the shift position in the travel range, N control is performed to release a predetermined amount of hydraulic pressure supplied to the clutch that connects / disconnects the turbine runner of the torque converter and the axle and slides the clutch. After the start of the N control, the difference between the engine speed and the turbine runner speed is detected, and the engine output is reduced on condition that the speed difference is less than a predetermined value. The control apparatus of the internal combustion engine characterized by performing the process for this was comprised.

  In addition, according to the present invention, when the vehicle stops with the shift position in the travel range, a predetermined amount of hydraulic pressure supplied to the clutch that connects and disconnects the turbine runner and the axle of the torque converter is released and the clutch is slid. After the N control is completed, the difference between the engine speed and the turbine runner speed is detected, and the engine output is determined on condition that the difference between the engine speeds exceeds a predetermined value. A control device for an internal combustion engine characterized in that processing for increasing is performed.

  According to the present invention, it is possible to suppress fluctuations in engine speed and shock when shifting to N control and / or when returning from N control.

The figure which shows the structure of the internal combustion engine in one Embodiment of this invention. The figure which shows the structure of the automatic transmission in the embodiment. The flowchart which shows the procedure of the process of N control which the control apparatus in the embodiment performs according to a program.

  An embodiment of the present invention will be described with reference to the drawings. The internal combustion engine 0 schematically showing the configuration of one cylinder in FIG. 1 is mounted on, for example, an automobile. The intake system 1 of the internal combustion engine 0 is provided with a throttle valve 11 that opens and closes according to the amount of depression of the accelerator pedal, and an intake manifold 12 that integrally has a surge tank 13 is attached downstream of the throttle valve 11. The surge tank 13 is provided with a pressure sensor for detecting the intake pipe pressure (or intake negative pressure).

An exhaust manifold 51 is attached to the exhaust system 5 and a three-way catalyst 52 for exhaust gas purification is attached. A front O ₂ sensor is disposed upstream of the catalyst 52 and a rear O ₂ sensor is disposed downstream. The O ₂ sensor outputs a voltage signal corresponding to the oxygen concentration in the exhaust gas by reacting in contact with the exhaust gas.

  An EGR device 6 is interposed between the intake system 1 and the exhaust system 5. The EGR device 6 includes an external EGR passage 61 having a start end communicating with the exhaust manifold 51 and a terminal end communicating with the surge tank 13, and an external EGR valve 62 provided on the EGR passage 61. If the EGR valve 62 is opened, an external EGR that recirculates the exhaust gas from the exhaust system 5 to the intake system 1 and mixes it with the intake air can be realized.

  An intake valve 21, an exhaust valve 22, an injector 3, and a spark plug 23 are provided on the ceiling portion (cylinder head) of the combustion chamber formed in the upper part of the cylinder 2.

  FIG. 2 shows an example of an automatic transmission. This automatic transmission is a continuously variable transmission including a torque converter 7 and a belt type CVT 9. The driving force output from the internal combustion engine 0 is input to the pump impeller 71 on the input side of the torque converter 7 and transmitted to the turbine runner 72 on the output side. The rotation of the turbine runner 72 is transmitted to the drive shaft 94 of the CVT 9 via the forward / reverse switching device 8 using a planetary gear mechanism, and rotates the driven shaft 95 through a shift in the CVT 9. An output gear 101 is fixed to the driven shaft 95, and this output gear 101 meshes with the ring gear 102 of the differential device to rotate the axle 103 and thus the drive wheel (not shown).

In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72 via the input shaft 73, and the ring gear 82 communicates with the drive shaft 94. Between the planetary carrier 83 that supports the planetary gear 831 and the transmission case, a forward brake 84 that is a hydraulic clutch that can be connected and disconnected is interposed. Further, a reverse clutch 85 that is a hydraulic clutch that can be connected and disconnected is also provided between the planetary carrier 83 and the sun gear 81 (or the input shaft 73). And the reverse clutch 85 is disconnected. As a result, the rotation of the input shaft 73 is reversed and decelerated and transmitted to the drive shaft 94 for forward travel. In turn, in the R range, the reverse clutch 85 is engaged and the forward brake 84 is disconnected. As a result, the sun gear 81 and the planetary carrier 83 rotate integrally, and the input shaft 73 and the drive shaft 94 are directly connected to perform reverse travel. In the N range and P range, which are non-traveling ranges, both the reverse clutch 84 and the forward brake 85 are disconnected.

  The CVT 9 includes a driving pulley 91 and a driven pulley 92, and a belt 93 wound around the pulleys 91 and 92 as elements. The drive pulley 91 is disposed behind the movable sheave 912, a fixed sheave 911 fixed to the drive shaft 94, a movable sheave 912 supported on the drive shaft 91 via a roller spline so as to be displaceable in the axial direction. A hydraulic servo 913 is provided, and the gear ratio can be changed steplessly by operating the hydraulic servo 913 and displacing the movable sheave 912. The driven pulley 92 is disposed on the back of the movable sheave 922, a fixed sheave 921 fixed to the driven shaft 95, a movable sheave 922 supported on the driven shaft 95 via a roller spline so as to be axially displaceable. A hydraulic servo 923 is provided, and a belt thrust necessary for torque transmission is applied by operating the hydraulic servo 923 and displacing the movable sheave 922.

  An electronic control unit 4 that controls the operation of the internal combustion engine 0 is a microcomputer system having a central processing unit 41, a storage device 42, an input interface 43, an output interface 44, and the like.

The input interface 43 outputs an intake pressure signal a output from a pressure sensor that detects the pressure in the intake pipe, a rotation speed signal b output from the rotation speed sensor that detects the engine speed, and a vehicle speed sensor 73 that detects the vehicle speed. Vehicle speed signal c, accelerator pedal position signal d output from an accelerator position sensor that detects the amount of accelerator pedal depression (or throttle valve 11 position), and shift lever position (that is, range) is detected. The shift position signal e output from the shift position switch, the water temperature signal f output from the water temperature sensor for detecting the coolant temperature, the crank angle signal output from the timing sensor at the end of the intake camshaft 91, and the cylinder discrimination signal g, 240 ° CA (crank angle) from the timing sensor at the end of the exhaust camshaft 92 Exhaust cam signal h which is output every rotation, the front O ₂ upstream air-fuel ratio signal i output from the sensor, downstream air-fuel ratio signal j outputted from the rear O ₂ sensor, the rotation of the turbine runner 72 of the torque converter 7 A rotational speed signal k output from a rotational speed sensor for detecting the number is input.

  From the output interface 44, the fuel injection signal n for the injector 3, the ignition signal m for the spark plug 8, the EGR valve opening signal o for the EGR valve 62, the transmission ratio signal p for CVT 9, and the forward brake 84 or a pressure control signal l or the like is output to a pressure control valve (solenoid valve) that adjusts the magnitude of the hydraulic pressure selectively supplied to the reverse clutch 85.

  The central processing unit 41 interprets and executes a program stored in the storage device 42 in advance, such as the fuel injection amount and ignition timing of the internal combustion engine 0, the EGR gas recirculation amount (intake EGR rate), the gear ratio, and the like. Carry out control.

  In the operation control of the internal combustion engine 0, the ECU 4 acquires various information a, b, c, d, e, f, g, h, i, j necessary for the operation control of the internal combustion engine 0 via the input interface 43. The current intake air amount and the EGR rate of the intake air are estimated, and based on these, the fuel injection amount, the fuel injection timing, the ignition timing, the opening degree of the EGR valve 62 (number of EGR steps), and the gear ratio of the CVT 9 The hydraulic pressure supplied to the forward brake 84 or the reverse clutch 85 is calculated. Then, control signals l, m, n, o, p, q corresponding to the calculated control input are applied via the output interface 44. Since the calculation method of the control input can be the same as the known operation control of the internal combustion engine 0, the description is omitted here.

  ECU4 which is a control apparatus in this embodiment implements N control, when a vehicle stops with a shift position being D range or R range which is a driving | running | working range.

  FIG. 3 shows a procedure of processing executed by the ECU 4 in the N control. When the shift position is the D range or the R range and the vehicle speed reaches 0 or a predetermined value close to 0 (step S1), it is determined that the N control is started, the pressure control valve is operated, and the forward brake The hydraulic pressure supplied to fasten 84 or reverse clutch 85 is released by a predetermined amount, specifically about 92% (step S2). That is, the hydraulic pressure supplied to the forward brake 84 or the reverse clutch 85 is reduced to about 8%. By step S2, the forward brake 84 or the reverse clutch 85, which was engaged before stopping, starts to slide.

  Then, the difference between the engine speed measured via the sensor and the rotational speed of the turbine runner 72 is calculated (step S3), and on the condition that the difference in rotational speed is less than a predetermined value (step S3). S4) A process for reducing the engine output is performed (step S5).

  The rotational speed difference between the engine 0 and the turbine runner 72 indicates how much load the engine 0 receives from the transmission side (how much work is being performed on the torque converter 7), in other words, the forward brake 84. Alternatively, this is an effective measure of how strong the reverse clutch 85 is engaged by the hydraulic pressure at the present time. By reducing the engine torque at a timing at which the difference in the rotational speed falls below a predetermined value, that is, at a timing at which the forward brake 84 or the reverse clutch 85 starts to slide, it is possible to appropriately prevent the engine rotational speed from fluctuating or blowing up.

  In step S5, the intake air amount and the fuel injection amount are corrected to decrease or the ignition timing is retarded.

  Therefore, when the accelerator opening is increased during N control or the vehicle speed is increased to a predetermined value or more (step S6), it is determined that the N control is to be ended, and the pressure control valve is operated to move forward. In order to re-engage the brake 84 or the reverse clutch 85, a predetermined amount of hydraulic pressure is supplied. Specifically, the hydraulic pressure that has been reduced to about 8% is increased by about 92% (step S7). By step S7, the forward brake 84 or the reverse clutch 85 that was slipping is completely engaged without slipping.

  Then, the difference between the engine rotational speed measured via the sensor and the rotational speed of the turbine runner 72 is calculated (step S8), and on condition that the rotational speed difference is equal to or greater than a predetermined value (step S9). Then, a process for recovering the reduced engine output is performed (step S10).

  As described above, the rotational speed difference between the engine 0 and the turbine runner 72 is an effective measure of how strong the forward brake 84 or the reverse clutch 85 is engaged by the hydraulic pressure at the present time. By increasing the engine torque at a timing at which this difference in rotational speed exceeds a predetermined value, that is, at a timing at which the forward brake 84 or the reverse clutch 85 is completely engaged, it is possible to appropriately suppress fluctuations in engine speed and stall.

  In step S10, the reduction correction of the intake air amount and the fuel injection amount is stopped (or the increase correction), or the ignition timing retardation correction is stopped (or the advance correction).

  According to the present embodiment, when the vehicle stops with the shift position at the travel range, the hydraulic pressure supplied to the clutches 84 and 85 for connecting / disconnecting the turbine runner 72 and the axle 103 of the torque converter 7 is released by a predetermined amount. N control for sliding the clutches 84 and 85 is performed, and after the start of the N control, the difference between the engine speed and the rotational speed of the turbine runner 72 is detected, and the rotational speed difference is a predetermined value. Since the control device 4 for the internal combustion engine 0 that performs the process for reducing the engine output on the condition that the engine power is less than the above is configured, the fluctuation of the engine speed and the shock during the shift to the N control can be suppressed. .

  In addition, when the vehicle stops with the shift position at the travel range, a predetermined amount of hydraulic pressure supplied to the clutches 84 and 85 for connecting / disconnecting the turbine runner 72 and the axle 103 of the torque converter 7 is released, and the clutch 84, N control for sliding 85 is performed, and after completion of the N control, a difference between the engine speed and the speed of the turbine runner 72 is detected, and the speed difference becomes a predetermined value or more. Since the control device 4 for the internal combustion engine 0 that performs the process for increasing the engine output under the condition is configured, it is possible to suppress the fluctuation of the engine speed and the shock when returning from the N control.

  Accordingly, the stability of idle operation is improved, and the intake air amount and the fuel injection amount are optimized, which contributes to the improvement of fuel consumption.

  The present invention is not limited to the embodiment described in detail above. For example, the automatic transmission in the above embodiment is a continuously variable transmission having a belt type CVT, but the present invention can naturally be applied even if a speed change mechanism other than the CVT is adopted. it can.

  In addition, the specific configuration of each unit, the processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

  The present invention can be used to control an internal combustion engine and an automatic transmission mounted on a vehicle.

0 ... Internal combustion engine 4 ... ECU (control device)
7 ... Torque converter 72 ... Turbine runner 84, 85 ... Clutch 103 ... Axle

Claims (2)

When the vehicle stops with the shift position in the travel range, N control is performed to release a predetermined amount of hydraulic pressure supplied to the clutch that connects and disconnects the turbine runner of the torque converter and the axle and slides the clutch. There,
After the start of the N control, a difference between the engine speed and the turbine runner speed is detected, and a process for reducing the engine output is performed on condition that the speed difference is less than a predetermined value. A control device for an internal combustion engine characterized by the above. When the vehicle stops with the shift position in the travel range, N control is performed to release a predetermined amount of hydraulic pressure supplied to the clutch that connects and disconnects the turbine runner of the torque converter and the axle and slides the clutch. There,
After the N control is completed, a difference between the engine speed and the turbine runner speed is detected, and a process for increasing the engine output is performed on condition that the speed difference becomes a predetermined value or more. A control device for an internal combustion engine characterized by the above.

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