JP2015143479A - Control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of shock while fastening a clutch interposed between an internal combustion engine and an axle as quick as possible, in a case of restarting the internal combustion engine having been subjected to idle stop.SOLUTION: In a case of restarting an internal combustion engine having been subjected to idle stop, every time ignition to air-fuel mixture filled with which a cylinder is filled is performed after starting cranking for restarting, the rotational speed of the internal combustion engine or the change amount of the rotational speed is detected, and according to whether the detected rotational speed or change amount is a predetermined value or more, the delay correction amount of ignition timing in next or later ignition opportunity to air-fuel mixture is adjusted.

Description

  The present invention relates to a control device for an idle stop vehicle.

  It is known to perform an idle stop for stopping the idle rotation of the internal combustion engine while the vehicle is stopped due to a signal waiting or the like (see, for example, Patent Document 1 below). In the existing idling stop system, when the vehicle speed is below a predetermined value, the brake pedal is depressed above a threshold value, and the conditions such as the cooling water temperature of the internal combustion engine and the voltage of the vehicle battery are sufficiently high, the internal combustion engine Stop the engine. During the idling stop, when there is a restart request such as when the driver removes his foot from the brake pedal or depresses the accelerator pedal, the internal combustion engine is restarted.

JP 2012-137018 A

  In a vehicle having a mode in which hydraulic fluid discharged from a mechanical pump that operates by receiving transmission of rotational torque from an internal combustion engine is supplied to a clutch interposed between the internal combustion engine and an axle (drive wheel), an idle stop is used. Since the operation of the hydraulic fluid pump stops, the clutch is disconnected during the idle stop.

  After that, when the idle stop termination condition is satisfied, the clutch must be quickly re-engaged because the vehicle needs to be able to re-start quickly. In order to fasten the clutch quickly, there is no other way than to rapidly increase the hydraulic fluid pressure supplied to the clutch. At this time, if the increase in the rotational speed of the internal combustion engine is steep, a shock may occur in the vehicle coupled with the rapid engagement of the clutch.

  If the hydraulic fluid pressure supplied to the clutch is slowly increased and it takes time to engage the clutch, it is possible to avoid a shock. However, a delay in clutch engagement leads to a delay in the restart of the vehicle after the end of the idle stop.

  The present invention has been made by paying attention to the above-mentioned problems for the first time, and suppresses the occurrence of shock while engaging the clutch as quickly as possible when restarting the internal combustion engine that has been idle-stopped. Is the intended purpose.

  In order to solve the above-described problems, in the present invention, a clutch interposed between an internal combustion engine and an axle is used by using the pressure of hydraulic fluid discharged from a mechanical pump that operates by receiving rotational torque from the internal combustion engine. A vehicle control device that engages and performs idle stop that stops idle rotation of an internal combustion engine when an idle stop condition is satisfied. After starting the ranking, each time the air-fuel mixture filled in the cylinder is ignited, the amount of change in the rotational speed or rotational speed of the internal combustion engine is detected, and whether the detected rotational speed or amount of change is equal to or greater than a predetermined value. Depending on whether or not, the control device is configured to adjust the retard correction amount of the ignition timing at the ignition opportunity to the air-fuel mixture after the next time.

  According to the present invention, when restarting the internal combustion engine that has been idle-stopped, it is possible to suppress the occurrence of shock while engaging the clutch as quickly as possible.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The figure which shows the structure of the drive system of the vehicle in the embodiment. The flowchart which shows the example of a procedure of the process which the control apparatus of the embodiment performs according to a program. The figure which shows typically transition of the raise of the rotational speed of the internal combustion engine during cranking for restart.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type 4-stroke gasoline engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  FIG. 2 shows an example of a drive system provided in the vehicle. This drive system includes a torque converter 7 and automatic transmissions 8 and 9. In particular, in the present embodiment, a forward / reverse switching device 8 using a planetary gear mechanism and a belt-type CVT (Continuously Variable Transmission) 9 which is a type of continuously variable transmission are adopted as components of the automatic transmissions 8 and 9. doing.

  The rotational torque output from the internal combustion engine is input from the crankshaft of the internal combustion engine 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 and rotates the driven shaft 95 through a shift in the CVT 9. The rotation of the driven shaft 95 is transmitted to the output gear 101. The output gear 101 meshes with the ring gear 102 of the differential device, and rotates the axle 103 and the drive wheels (not shown) via the differential device.

  The torque converter 7 includes a lockup mechanism. The lock-up mechanism is known in this field, and a lock-up clutch 73 that fastens the input side and the output side of the torque converter 7 so as not to rotate relative to each other, and an operation for switching the connection of the lock-up clutch 73. A lock-up solenoid valve (not shown) for controlling the hydraulic pressure (hydraulic pressure) is used as an element. The lockup solenoid valve is a flow rate control valve that receives a control signal l and changes its opening.

  In a vehicle equipped with CVT 9, when the vehicle speed is a predetermined value (for example, 10 km / h) or more, the torque converter 7 is almost always locked up. When the vehicle speed is equal to or lower than the predetermined value, the lockup of the torque converter 7 is released. During lockup, the lockup clutch 73 is pressed against the torque converter cover 74 and rotates together with the torque converter cover 74. The engine torque input to the input side (drive plate) of the torque converter 7 at the time of lock-up is output from the torque converter cover 74 via the lock-up clutch 73 and thus to the forward / reverse switching device 8. Communicated directly to. At the time of lockup, the speed ratio, which is the ratio of the output side rotational speed of the torque converter 7 to the input side rotational speed, is 1.

  In turn, the lock-up clutch 73 is separated from the torque converter cover 74 at the time of non-lock-up. At the time of non-lock-up, the engine torque input to the input side of the torque converter 7 is transmitted from the torque converter cover 74 to the pump impeller 71 and the turbine 72 and is transmitted to the forward / reverse switching device 8. At the time of non-lock-up, the speed ratio of the torque converter 7 becomes smaller or larger than 1 depending on the driving state.

  In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72, 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, which is a hydraulic clutch capable of switching connection / disconnection, is also interposed between the planetary carrier 83 and the sun gear 81 (or the output side of the torque converter 7).

  In the D range of the traveling range, the forward brake 84 is engaged and the reverse clutch 85 is disconnected. As a result, the rotation of the output shaft of the torque converter 7 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 output shaft of the torque converter 7 and the drive shaft 94 are directly connected to perform reverse travel. A solenoid valve (not shown) that controls the hydraulic pressure for driving the forward brake 84 or the reverse clutch 85 to connect / disconnect is a flow rate control valve that receives a control signal m and changes its opening.

  In the N range and P range, which are non-traveling ranges, both the forward brake 84 and the reverse clutch 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.

  The hydraulic fluid (hydraulic fluid) supplied to the forward brake 84 or the reverse clutch 85 to operate the travel range and the hydraulic fluid supplied to the hydraulic servos 913 and 923 to operate the gear ratio are used for the torque converter 7. It is common with the fluid to be used. This fluid is referred to as transmission fluid (CVTF). The hydraulic fluid pump 76 that sucks and discharges the fluid is located between the torque converter 7 and the forward / reverse switching device 8 and operates by receiving torque from the crankshaft of the internal combustion engine. Electric type). The fluid is also used for lubrication of the forward / reverse switching device 8 and the belt 93 of the CVT 9 and for preventing sliding friction of the belt 93 with respect to the pulleys 91 and 92.

  The ECU 0 as the control device of the present embodiment is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle and engine speed of the crankshaft, and depression of an accelerator pedal. An accelerator opening degree signal c output from a sensor that detects the amount or the opening degree of the throttle valve 32 as an accelerator opening degree (so-called required load), detects whether the brake pedal is depressed, or detects the depression amount of the brake pedal. Brake switch or pedaling amount signal d output from the sensor, intake air temperature / intake pressure signal e output from a temperature / pressure sensor that detects intake air temperature and intake negative pressure in the intake passage 3 (especially the surge tank 33), A cooling water temperature signal f output from a water temperature sensor for detecting a cooling water temperature indicating the temperature of the internal combustion engine; Cam angle signal g output from the cam angle sensor at a plurality of cam angles of the camshaft or exhaust camshaft, shift range signal h output from a sensor (or shift position switch) for knowing the range of the shift lever, etc. Is entered.

  From the output interface, an ignition signal i for the igniter 13 of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and switching of connection / disconnection of the lockup clutch 73. An opening degree control signal l is outputted to the lockup solenoid valve, an opening degree control signal m is outputted to the solenoid valve for switching connection / disconnection of the forward brake 84 or the reverse clutch 85, a transmission ratio control signal n is outputted to the CVT 9, etc. .

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and is filled in the cylinder 1. Estimate the intake volume. Based on the engine speed, the intake air amount, etc., the required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, ignition timing, torque converter 7 Operation parameters such as whether or not to perform lockup and the gear ratio of the automatic transmissions 8 and 9 are determined. The ECU 0 applies various control signals i, j, k, l, m, and n corresponding to the operation parameters via the output interface.

  The ECU 0 inputs a control signal o to an electric motor (starter motor or motor generator, not shown) at the time of starting the internal combustion engine (a cold start or a return from an idling stop), Cranking is performed by rotating the crankshaft with an electric motor. Cranking ends when the internal combustion engine starts from the first explosion to a continuous explosion and the engine speed, that is, the rotation speed of the crankshaft, exceeds a judgment value determined according to the coolant temperature, etc. (assuming that the explosion has been completed) To do.

  The ECU 0 of the present embodiment performs an idle stop that stops the idle rotation of the internal combustion engine when the vehicle stops due to a signal waiting or the like.

  FIG. 3 shows a procedure example of processing executed by the ECU 0 when the vehicle decelerates and stops. When the idle stop condition is satisfied (step S1), the ECU 0 starts executing an idle stop that stops the idle rotation of the internal combustion engine (step S2).

  In step S1, the vehicle speed is equal to or lower than a predetermined value (for example, a value of 10 km / h to 13 km / h) and the driver depresses the brake pedal (the brake switch is turned on) or the brake operation amount (depresses the brake pedal). Amount or master cylinder pressure) exceeds the determination threshold, the coolant temperature and the battery voltage are each higher than a predetermined value, and the vehicle speed is a predetermined value (for example, 10 km / h to 13 km / h) after the most recent restart of the internal combustion engine. Value)), it is determined that the idle stop condition is satisfied when all the conditions such as there is a history of rising above are all satisfied.

  During the idle stop in which the idle rotation of the internal combustion engine stops, the operation of the hydraulic fluid pump 76 is also stopped. Therefore, the hydraulic fluid pressure supplied to the forward brake 84 as a clutch is lost, and the forward brake 84 that has been engaged is disconnected.

  After the idle stop condition is satisfied, when the idle stop end condition is satisfied (step S3), cranking for restarting the internal combustion engine is started (step S4).

  In step S3, the driver removes his / her foot from the brake pedal (the brake switch is OFF) or the brake operation amount (the brake pedal depression amount or the master cylinder pressure) is below the determination threshold value. Depressed (the brake pedal depression amount or master cylinder pressure further increased), the accelerator pedal was depressed, a predetermined time (for example, 3 minutes) passed in the idle stop state, etc. Thus, it is determined that the idle stop termination condition is satisfied.

  After the cranking of the internal combustion engine is started, fuel is injected from the injector 11 in each cylinder 1, and the air-fuel mixture filled in the cylinder 1 is spark-ignited by the spark plug 12 of the cylinder 1 to burn it.

  Unlike cold start, when restarting from idle stop, the temperature of the internal combustion engine is already sufficiently high and the viscosity of the engine oil is also low. Therefore, the mechanical loss of the internal combustion engine is small compared to the cold start, and the engine speed can be accelerated quickly. Furthermore, the cranking period is short compared to the cold start, and the intake pressure in the surge tank 33 is relatively high (the intake negative pressure is low). For this reason, a large amount of intake air flows into the cylinder 1 and tends to output a larger engine torque than in the cold start. Therefore, if the air-fuel mixture is ignited at the same ignition timing as that of the cold start, the engine speed rapidly increases, and the engine speed greatly blows up after the complete explosion occurs. In addition, when the forward brake 84 that has been disconnected is re-engaged, a shock is generated, which may cause discomfort and discomfort to passengers including the driver.

  Therefore, the ignition timing at the restart after the idle stop is retarded from the ignition timing at the cold start. Thereby, increase in engine torque and suppression of acceleration of engine speed are aimed at.

The ECU 0 of the present embodiment then detects the rotational speed of the internal combustion engine or the amount of change in the rotational speed via the engine rotation sensor every time the air-fuel mixture charged in the cylinder 1 is ignited (step S5). ). FIG. 4 schematically shows a change in the rotational speed of the internal combustion engine during cranking. In the figure, V _i represents the engine speed (a maximum value) measured after the i-th ignition opportunity, and ΔV _i represents the engine speed V measured after the (i−1) -th ignition opportunity. _It represents the difference between _i-1 and the engine speed V _i measured after the i-th ignition opportunity, that is, the amount of increase in the engine speed.

  In other words, the ignition opportunity is an opportunity for combustion (expansion stroke) of the air-fuel mixture in any of the cylinders 1. In an internal combustion engine including a plurality of cylinders 1, it is normal that the cylinder 1 that has performed the (i-1) th ignition combustion is different from the cylinder 1 that has performed the i-th ignition combustion.

Thus, the ECU 0 compares the engine speed V _i detected after the i-th ignition opportunity with the target value T _i of the engine speed after the i-th ignition opportunity and / or after the i-th ignition opportunity. The engine speed change ΔV _i is compared with the target engine speed acceleration ΔT (step S8).

If the engine speed V _i is equal to or greater than the target value T _i and / or the change amount ΔV _i of the engine speed is equal to or greater than the acceleration target value ΔT, it is necessary and sufficient to accelerate the rotation of the internal combustion engine. However, it is allowed to retard the engine torque by retarding the ignition timing at the next (i + 1) th ignition opportunity. Therefore, the ignition timing at the (i + 1) th ignition opportunity is retarded from the ignition timing at the cold start (step S9).

On the other hand, if the engine speed V _i is less than the target value T _i and / or if the engine speed change amount ΔV _i is less than the acceleration target value ΔT, acceleration of the internal combustion engine is not accelerated. Therefore, it is better to increase the engine torque without retarding the ignition timing at the (i + 1) th ignition opportunity. Therefore, even if the ignition timing at the (i + 1) th ignition opportunity is made equal to the ignition timing at the cold start or retarded from the ignition timing at the cold start, the retard correction amount is compared with step S9. Decrease (step S10).

If the engine speed V _i exceeds a threshold determined according to the coolant temperature or the like (step S6), and ends the cranking (step S7).

In the present embodiment, the clutch 84 interposed between the internal combustion engine and the axle 103 is fastened using the pressure of the hydraulic fluid discharged from the mechanical pump 76 that operates by receiving transmission of rotational torque from the internal combustion engine, A control device for a vehicle that performs idle stop for stopping idle rotation of an internal combustion engine when an idle stop condition is satisfied, and when restarting the internal combustion engine that has been idle stopped, starts cranking for the start from to, every time to ignite an air-fuel mixture charged into the cylinder 1, to detect the rotational speed V _i or the rotation speed variation [Delta] V _i of the internal combustion engine, the detected rotational speed V _i or the amount of change [Delta] V _i There, depending on whether or not a predetermined (T _i or [Delta] T) or more, to constitute a control apparatus 0 for adjusting the retard correction amount of ignition timing in the ignition opportunities for the air-fuel mixture next time.

According to this embodiment, when restarting the internal combustion engine has been idle stop, the degree of increase of the rotational speed V _i, can be suppressed to the extent that large shock due to the engagement of the clutch 84 does not occur. Accordingly, the hydraulic fluid supplied to the clutch 84 is allowed to rapidly increase and the clutch 84 is allowed to be fastened as quickly as possible, so that the vehicle can be brought into a state where the vehicle can be restarted quickly, and drivability is improved. Contribute to improvement.

  Further, since the engine speed increase due to the restart can be suppressed, the number of times of fuel injection and combustion can be reduced accordingly.

  The present invention is not limited to the embodiment described in detail above. The specific configuration of each part and the specific processing procedure can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of a vehicle equipped with an internal combustion engine.

0 ... Control unit (ECU)
DESCRIPTION OF SYMBOLS 1 ... Cylinder 12 ... Spark plug 76 ... Mechanical pump 84 ... Clutch 103 ... Axle

Claims (1)

When the clutch that is interposed between the internal combustion engine and the axle is engaged using the pressure of the hydraulic fluid discharged from the mechanical pump that operates by receiving rotational torque from the internal combustion engine, and when the idle stop condition is satisfied A control device for a vehicle that performs idle stop for stopping idle rotation of an internal combustion engine,
When restarting an internal combustion engine that has been idle-stopped, every time ignition is performed on the air-fuel mixture filled in the cylinder after starting cranking for that start, the amount of change in the rotational speed or rotational speed of the internal combustion engine , And a control device that adjusts a retard correction amount of the ignition timing at the ignition opportunity for the air-fuel mixture after the next time, depending on whether or not the detected rotational speed or change amount is equal to or greater than a predetermined value.

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