JP6021548B2 - Idle stop vehicle control device - Google Patents

Description

  The present invention relates to a control device that controls an idle stop vehicle including a continuously variable transmission.

  2. Description of the Related Art An idling stop system that improves fuel efficiency by stopping idle rotation of an internal combustion engine when a vehicle is temporarily stopped, such as waiting for a signal, is well known. In the idling stop system, the internal combustion engine is automatically stopped when various conditions such as the vehicle speed is equal to or lower than a predetermined value, the brake pedal is depressed, the coolant temperature and the battery voltage are sufficiently high, that is, the idle stop condition is satisfied. (For example, see Patent Document 1).

  By the way, in the control described in Patent Document 1, the idle stop condition includes a condition that the gradient is equal to or less than a predetermined gradient. This condition is set in order to suppress or prevent the occurrence of problems described below. In other words, in a vehicle equipped with a continuously variable transmission, control for shifting the gear ratio to a low speed side during deceleration is widely performed, but if an idle stop is performed on an uphill, the gear ratio does not sufficiently become a low speed side. In this state, the internal combustion engine is stopped and the speed change ratio cannot be changed. When the internal combustion engine is restarted, the speed change ratio is further lowered before starting, and the start acceleration performance may deteriorate.

  Here, if the predetermined gradient is set to a gentle gradient, the occurrence of the above-described problems can be suppressed. However, when the predetermined gradient is set to a gentle gradient in this way, on the contrary, even when the gear ratio is sufficiently low, the condition that the gradient is equal to or less than the predetermined gradient is not satisfied. This may cause a new problem that fuel efficiency is not improved sufficiently.

JP 2012-117413 A

  The present invention pays attention to the above points and aims to improve fuel efficiency by increasing the number of idling stops while improving the acceleration of starting on a slope.

  In order to solve the above problems, the control apparatus for an idle stop vehicle according to the present invention performs the following control. That is, the control device for an idle stop vehicle according to the present invention is a control device that performs idle stop for stopping idling of an internal combustion engine equipped with a continuously variable transmission, and when the vehicle decelerates and the vehicle speed becomes a predetermined value or less. It is determined whether or not an idle stop condition for performing an idle stop is satisfied, and the ascending slope determination threshold of the idle stop condition is increased as the speed ratio of the continuously variable transmission becomes lower. Is set.

  In such a case, when the speed ratio of the continuously variable transmission is on the low speed side, there is no need to further reduce the speed ratio when the internal combustion engine is restarted on an uphill even when the idle stop is performed. Since the acceleration of starting on a slope can be ensured, the upward gradient determination threshold value can be increased, and the idle stop can be performed even on a somewhat steep uphill to improve fuel efficiency. The present invention is particularly advantageous in a vehicle including a continuously variable transmission that does not include a sub-transmission mechanism that is a mechanism capable of shifting even when the internal combustion engine is stopped.

  In an idle stop vehicle control device that performs control to reduce the speed ratio of the continuously variable transmission as the vehicle speed decreases, as a configuration suitable for further increasing the frequency of idle stop in order to further improve fuel consumption, When it is determined that the idle stop condition is not satisfied, when the vehicle speed is lower than the predetermined value, it is repeatedly determined whether the idle stop condition is satisfied.

  In particular, when it is determined that the idle stop condition is not satisfied because the gradient is on the steep side from the uphill determination threshold value, the speed ratio of the continuously variable transmission is set to the low speed side as the vehicle speed decreases. If the control is to make the speed higher than normal, use the fact that the feeling of discomfort is small even when the speed reduction feeling felt by the occupant increases when the speed ratio of the continuously variable transmission is set to the low speed side during deceleration on the uphill. By quickly setting the speed ratio to the low speed side, it is possible to extend the period during which the idle stop state is set.

  According to the present invention, it is possible to improve fuel efficiency by increasing the number of idling stops while improving start acceleration on a slope.

1 is a schematic diagram showing the configuration of a vehicle internal combustion engine according to an embodiment of the present invention. Schematic which shows the structure of the drive system in the embodiment. The flowchart which shows the example of a procedure of the process which the control apparatus of the embodiment implements. The figure which shows the relationship between the vehicle speed of the embodiment, and idle stop conditions.

  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. The internal combustion engine in the present embodiment is a spark ignition 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. The gear ratio, that is, the pulley 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.

  A hydraulic pump (hydraulic fluid) supplied to the forward brake 84 or the reverse clutch 85 to operate the travel range, and a hydraulic pump (discharge fluid) supplied to the hydraulic servos 913 and 923 to operate the gear ratio. (Not shown) is a known mechanical type (non-electric type) that operates by receiving torque transmitted from the crankshaft of the internal combustion engine. This hydraulic fluid is common to the fluid used for the torque converter 7.

  An ECU (Electronic Control Unit) 0 that is a 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 (N signal) b output from an engine rotation sensor that detects the rotation angle of the crankshaft and the engine speed, Accelerator depression signal c output from a sensor that detects the amount of depression of the accelerator pedal (so-called required load), brake depression signal d output from a sensor that detects the depression of the brake pedal 6 or master cylinder pressure, intake air Intake temperature / intake negative pressure signal e output from a temperature / pressure sensor for detecting intake temperature and intake negative pressure in the passage 3 (particularly, surge tank 33), pressure for detecting negative pressure in the constant pressure chamber of the brake booster 5 Is the sensor (shift position switch) for knowing the constant-pressure chamber negative pressure signal f output from the sensor and the shift lever range? Output shift range signal g, cam angle signal (G signal) h output from cam angle sensor at multiple cam angles of intake camshaft or exhaust camshaft, acceleration signal i output from acceleration sensor, etc. Is done.

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

  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 obtains various information a, b, c, d, e, f, g, h, i necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and fills the cylinder 1 Estimate the amount of intake air. Based on the engine speed, the intake air amount, and the like, various operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, and ignition timing are determined. A known method can be adopted as the operation parameter determination method itself. The ECU 0 applies various control signals j, k, l, m, n, and o corresponding to the operation parameters via the output interface.

  In addition, the ECU 0 executes the idle stop control program built in the memory so that the idle stop condition is satisfied, specifically, the shift position indicated by the shift range signal g is the travel range (AT In the case of a car), the brake pedal depression amount indicated by the brake depression amount signal d is equal to or greater than the predetermined depression amount, and the negative pressure in the constant pressure chamber of the brake booster indicated by the constant pressure chamber negative pressure signal f is the predetermined brake booster negative pressure (predetermined pressure). More than the vacuum side), and the upward gradient indicated by the acceleration signal i is equal to or lower than the upward gradient determination threshold (in addition, the voltage of the on-vehicle battery is equal to or higher than the predetermined voltage and the cooling water temperature of the internal combustion engine is equal to or higher than the predetermined water temperature Yes, whether or not the conditions such as the lubricating oil temperature is equal to or higher than the predetermined oil temperature and the intake air temperature is equal to or higher than the predetermined intake temperature are satisfied. Was carried out, it performs control to stop operation of the internal combustion engine when the idle stop condition is satisfied. When the idle stop control program is being executed, if the idle stop condition is not satisfied because the uphill slope is equal to or higher than the uphill slope determination threshold, the idle stop control program is controlled. Compared with the case where it is not, the control which makes the gear ratio of CVT9 the low speed side is performed quickly.

  Further, the ECU 0 inputs a control signal p to a starter motor (cell motor, not shown) when starting the internal combustion engine (a cold start or a return from an idling stop). Cranking is performed by rotating the engine by engaging the pinion gear of the motor with the ring gear on the outer periphery of the drive plate. Cranking ends from the first explosion to the consecutive explosion, and ends when the engine speed exceeds a judgment value determined according to the cooling water temperature or the like (assuming that the explosion has been completed).

  FIG. 3 shows a procedure of processing executed by the ECU 0 by the idle stop control program of the present embodiment. When the ECU 0 detects that the vehicle has decelerated and the vehicle speed has become a predetermined value (for example, 7 km / h) or less (step S1), the ECU 0 determines an upward gradient determination threshold using the transmission ratio of the CVT 9 as a parameter (step S2). ), It is determined whether or not an idle stop condition is satisfied (step S3). If the idle stop condition is satisfied, the idle stop control is continued as if an idle stop request has been made (step S4). On the other hand, if the idle stop condition is not satisfied because the ascending slope is equal to or greater than the ascending slope determination threshold value (step S5), the gear ratio of CVT 9 is set to the low speed side, that is, the LOW gear side in conjunction with the decrease in the vehicle speed. (Step S6), and thereafter, the control after step S1 is repeated. On the other hand, when the idle stop condition is not satisfied due to other reasons, the control after step S1 is repeated as it is. Here, the speed at which the gear ratio of the CVT 9 is increased is set to be faster than when the control by the idle stop control program is not performed.

  Here, as shown in FIG. 4, the upward gradient determination threshold increases as the gear ratio of the CVT 9, that is, the pulley ratio becomes lower, that is, as the LOW gear side. This is because, when the gear ratio is on the high speed side, that is, on the HIGH gear side, on an uphill that is somewhat steep, if the idle stop is performed, it will be necessary to make the gear ratio on the low speed side at the time of subsequent restart. In order to ensure the start acceleration of the engine, it is necessary to set the speed ratio to the low speed side before continuing the internal combustion engine operation and performing the idle stop, whereas the speed ratio is on the low speed side, that is, on the LOW gear side. In some cases, even if the slope is steep to some extent, it is reflected that the vehicle can be started without changing the gear ratio to a lower speed side at the time of restart after idle stop. In other words, the idle stop condition is set such that the possibility that the idle stop is executed increases as the gear ratio becomes lower.

  In other words, according to the control of the present embodiment, when the transmission ratio of the CVT 9 is sufficiently low, the transmission ratio needs to be further reduced when the internal combustion engine is restarted on an uphill even when idle stop is performed. Focusing on the fact that start acceleration on a slope can be ensured, and when the gear ratio of the CVT 9 is on the low speed side, by increasing the uphill determination threshold, idle stop can be performed even on a somewhat steep uphill. This can improve fuel efficiency. In other words, without providing a separate sub-transmission mechanism that can change gears even when the internal combustion engine is stopped, while improving the acceleration of starting on a slope, the number of idling stops can be increased to improve fuel efficiency. Can be planned.

  Further, even before the vehicle stops, the idle stop is performed when the idle stop condition is satisfied. Therefore, the period for performing the idle stop is made longer to improve the fuel efficiency. be able to.

  Furthermore, when it is determined that the idle stop condition is not satisfied because the ascending slope is steeper than the ascending slope determination threshold, the speed at which the speed ratio of the CVT 9 is lowered as the vehicle speed decreases. Since the control is performed faster than usual, the speed ratio is quickly reduced to the low speed side by taking advantage of the fact that the CVT 9 speed ratio is low and the occupant feels a sense of incongruity when the speed ratio is low. By doing so, the period during which the idle stop state is set can be made longer.

  The present invention is not limited to the embodiment described above.

  For example, in the above-described embodiment, it is determined whether or not the idle stop condition is satisfied when it is detected that the vehicle decelerates and the vehicle speed is equal to or lower than a predetermined value, and it is determined that the idle stop condition is not satisfied. After that, if the vehicle speed is less than or equal to the predetermined value, it is repeatedly determined whether or not the idle stop condition is satisfied, but after it is determined that the idle stop condition is not satisfied, until the stop of the vehicle is detected Control may be performed so as not to determine whether or not the idle stop condition is satisfied, and when the vehicle speed becomes a second predetermined value on the lower speed side than the predetermined value, the idle stop condition is satisfied again. Control may be performed to determine whether or not there is.

  Further, in the above-described embodiment, when it is determined that the idle stop condition is not satisfied because the gradient is on the steep slope side with respect to the upward gradient determination threshold, the speed ratio of the continuously variable transmission is set as the vehicle speed decreases. Although the control is performed so that the speed on the low speed side is higher than the normal speed, the speed ratio of the continuously variable transmission may be set on the low speed side as the vehicle speed decreases at the same speed as normal.

  In addition, various changes may be made without departing from the spirit of the present invention.

0 ... ECU (control device)
9 ... CVT (continuously variable transmission)
a ... Vehicle speed signal i ... Acceleration signal

Claims (3)

A control device for performing an idle stop for stopping idling of an internal combustion engine provided with a continuously variable transmission,
It is determined whether or not an idle stop condition for performing an idle stop is satisfied when the vehicle decelerates and the vehicle speed becomes a predetermined value or less,
A control device for an idle stop vehicle in which an uphill gradient determination threshold value is set so as to increase as the gear ratio of the continuously variable transmission becomes lower in the idle stop condition. A control device for an idle stop vehicle that performs control to reduce the speed ratio of the continuously variable transmission to a low speed side as the vehicle speed decreases,
2. The idle stop vehicle according to claim 1, wherein when it is determined that the idle stop condition is not satisfied, control is performed to repeatedly determine whether the idle stop condition is satisfied when the vehicle speed is less than the predetermined value. Control device. If it is determined that the idle stop condition is not satisfied because the gradient is on the steep side from the upgradation determination threshold, the speed at which the speed ratio of the continuously variable transmission is set to the low speed side as the vehicle speed decreases is set. The control apparatus for an idle stop vehicle according to claim 2, wherein the control is performed to make the control faster than usual.

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