JP2015121184A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase opportunities of idle stop in an idle stop vehicle.SOLUTION: In a vehicle in which idle stop for stoping idle rotation of an internal combustion engine is carried out when idle stop conditions are established, an acceleration history condition that a history of increase of vehicle speed to a prescribed value or more after the latest restart of the internal combustion engine exists, is included as one of idle stop conditions, and on the other hand, the acceleration history condition is not included in the idle stop conditions until the lapse of a grace time from detection that the vehicle speed is lowered to 0 or a value near 0, when the idle stop is started before the vehicle speed becomes 0. The grace time is variable according to a situation of the vehicle or a situation of a road surface after the idle stop is started before the vehicle speed becomes 0.

Description

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

  It is known to perform an idle stop that stops the idle rotation of the internal combustion engine while the vehicle is stopped due to a signal or the like (see, for example, Patent Documents 1 and 2 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.

  One of the conditions for starting execution of idle stop is an acceleration history condition in which there is a history that the vehicle speed has risen above a predetermined value after the most recent restart of the internal combustion engine. This is to prevent frequent repetition of idle stop and restart of the internal combustion engine on a congested road (see Patent Document 2 below).

JP 2012-137018 A Japanese Patent Laid-Open No. 11-257121

  Recently, in order to further improve the fuel consumption performance of the vehicle, the vehicle speed condition, which is one of the idle stop conditions, is increased and the idle stop is started before the vehicle stops.

  During the process of driving the vehicle, the driver may step on the brake pedal, and the driver may loosen the brake pedal that was depressed to adjust the deceleration of the vehicle in the process of braking and stopping the vehicle. . In particular, in vehicles equipped with an automatic transmission, the reduction ratio of the automatic transmission increases (ie, shifts to low gear) as the vehicle speed decreases, and the deceleration of the vehicle increases. Try to alleviate. As a result, contrary to the driver's intention to stop, the internal combustion engine that has been idle-stopped once restarts.

  Thereafter, even if the driver depresses the brake pedal and the vehicle completely stops, the existence of the acceleration history condition described above prevents the establishment of the idle stop condition. Therefore, when the idling stop is started before the vehicle speed becomes zero, the acceleration history is from the time when it is detected that the vehicle speed has decreased to zero or a value close to zero to the time when a grace period (for example, 2 seconds) elapses. The condition is not included in the idle stop condition. As a result, the idle stop can be performed again.

  However, due to the detection limit of the vehicle speed sensor mounted on the vehicle, the electronic control unit (Electronic Control Unit) that controls the internal combustion engine actually drops to 0 before the vehicle stops. I will judge. And since the grace time is counted from the judgment time point, the grace time has already passed when the vehicle actually stops, and the idle stop may not be resumed even though the driver steps on the brake pedal. Occur. If this is the case, it not only hinders improvement in fuel efficiency, but may also give the driver a sense of incongruity.

  The present invention, which has been made by paying attention to the above problems for the first time, is intended to increase the chance of idle stop in an idle stop vehicle.

  In order to solve the above-described problem, the present invention is a vehicle control apparatus that performs idle stop for stopping idle rotation of an internal combustion engine when an idle stop condition is satisfied, and one of the idle stop conditions includes: While there is an acceleration history condition that there is a history that the vehicle speed has risen above a predetermined value after the most recent restart of the internal combustion engine, if the idle stop is started before the vehicle speed becomes 0, the vehicle speed has dropped to 0 From the time when this is detected until the grace time elapses, the acceleration history condition is not included in the idle stop condition, and the grace time is set to the vehicle after the idle stop is started before the vehicle speed becomes zero. The control device was made variable according to the situation of the road or the road surface.

  When the vehicle deceleration after starting the idling stop before the vehicle speed becomes zero is relatively small, the grace time is determined by the amount of brake operation by the driver after starting the idling stop before the vehicle speed becomes zero. It is desirable to set a longer time when the vehicle is relatively small and / or when the downhill slope of the road surface on which the vehicle is located after the start of the idle stop before the vehicle speed becomes zero is relatively large.

  ADVANTAGE OF THE INVENTION According to this invention, the opportunity of the idle stop in an idle stop vehicle can be increased.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. 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 timing diagram which shows the content of the control which the control apparatus of the embodiment performs.

  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.

  A brake booster 5 is attached to the vehicle of this embodiment. The brake booster 5 introduces intake negative pressure from a portion of the intake passage 3 downstream of the throttle valve 32, more specifically, from the surge tank 33, and uses this negative pressure to boost the pedaling force of the brake pedal. It is widely known in the field. The brake booster 5 has a constant pressure chamber for storing negative pressure and a variable pressure chamber for applying atmospheric pressure, and the constant pressure chamber is connected to the surge tank 33 via the negative pressure line 51. The negative pressure line 51 guides the intake negative pressure downstream of the throttle valve 32 to the constant pressure chamber. A check valve 52 is provided on the negative pressure line 51 to keep the negative pressure in the constant pressure chamber and prevent the positive pressure from being applied to the constant pressure chamber.

  When the brake pedal is not operated by the driver, the constant pressure chamber and the variable pressure chamber communicate with each other, and the variable pressure chamber is isolated from the atmospheric pressure. When the brake pedal is operated, the constant pressure chamber and the variable pressure chamber are interrupted, and the atmosphere is introduced into the variable pressure chamber. As a result, the pressure difference between the constant pressure chamber and the variable pressure chamber becomes a control pressure that boosts the depression force of the brake pedal. The brake pedal force amplified by the brake booster 5 is converted into hydraulic pressure in the master cylinder 6. The hydraulic fluid pressure output from the master cylinder 6 is transmitted to a brake device (not shown) such as a brake caliper or a wheel cylinder via a hydraulic circuit (not shown), and is used for braking the vehicle by the brake device.

  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), Cooling water temperature signal f output from a water temperature sensor that detects the cooling water temperature indicating the temperature of the internal combustion engine, the vehicle is located An inclination angle (or acceleration) signal g output from an inclination angle sensor (or acceleration sensor) that detects the gradient of the road surface that is being detected, and a liquid that detects a master cylinder pressure that is the pressure of hydraulic fluid discharged from the master cylinder 6 A master cylinder pressure signal h and the like output from the pressure sensor are input.

  From the output interface, an ignition signal i is output to the igniter 13 of the spark plug 12, a fuel injection signal j is output to the injector 11, an opening operation signal k is output to the throttle valve 32, 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 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, 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. The ECU 0 applies various control signals i, j, k 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. 2 shows a procedure example of processing executed by the ECU 0 when the vehicle decelerates and stops. When the idle stop condition is satisfied (steps S1 and S9), the ECU 0 starts executing an idle stop that stops the idle rotation of the internal combustion engine (step S4).

  In steps S1 and S9, 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 is stepping on the brake pedal (the brake switch is ON) or the brake operation amount (brake pedal The amount of depression of the engine or the master cylinder pressure) exceeds the determination threshold, the cooling water temperature and the battery voltage are both higher than predetermined values, and the vehicle speed becomes a predetermined value (for example, 10 km / h to 13 km / h) after the most recent restart of the internal combustion engine. It is determined that the idle stop condition is satisfied when all of the conditions such as the history of increase in value h) are satisfied.

  However, as will be described later, from the time of detecting that the vehicle speed has decreased to 0 or a value close to 0 until the time when the grace time has elapsed, from the idle stop condition, “the vehicle speed after the most recent restart of the internal combustion engine” The acceleration history condition that “there is a history in which the value has risen above a predetermined value” is removed (steps S2 and S3). That is, until the grace time elapses, the idle stop is started when the other idle stop conditions are satisfied, even if there is no history of the vehicle speed increasing above the predetermined value. In turn, after the grace time has elapsed (step S7), it is not recognized that the idle stop condition is satisfied unless there is a history that the vehicle speed has increased to a predetermined value or more as usual (step S8).

  After the idle stop condition is established, when the idle stop end condition is established (step S5), the internal combustion engine is restarted (step S6).

  In step S5, 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) falls 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.

  If the idling stop is started before the vehicle speed becomes zero (step S2), the above-mentioned acceleration history condition is set to the idling stop until the grace time elapses after the vehicle speed is detected to be zero. It is not included in the conditions (step S3).

  The purpose of the driver adjusting the deceleration of the vehicle after the driver depresses the brake pedal while the vehicle is running and the idle stop condition (steps S1 and S9) is established and the idle stop is started (step S4). In some cases, the brake pedal that was being depressed may be released. Then, contrary to the driver's intention to stop, an idle stop termination condition is established (step S5), and the internal combustion engine once idle-stopped is restarted (step S6).

  Thereafter, even if the driver depresses the brake pedal and the vehicle is completely stopped, as long as the acceleration history condition exists, the establishment of the idle stop condition is prevented. Therefore, the acceleration history condition is excluded from the idle stop condition from the time when it is detected that the vehicle speed has decreased to 0 to the time when the grace time elapses. As a result, the idle stop can be performed again.

  Therefore, in the present embodiment, the above-described grace time is adjusted according to the vehicle condition or road surface condition after the idle stop is started before the vehicle speed becomes zero.

  FIG. 3 shows changes in vehicle speed, ON / OFF of the brake switch, and ON / OFF of the idle stop flag when the idle stop is started before the vehicle speed becomes zero. In FIG. 3, time t0 is the time when the initial idle stop condition is satisfied (before the vehicle speed becomes 0), time t1 is the time when ECU 0 detects that the vehicle speed has become 0, and time t2 is the time when the driver The time point t3 is the time point when the idle stop condition is satisfied again (after the internal combustion engine is restarted), and the time point t4 is the time point when the grace time has elapsed.

  Due to the detection limit of the vehicle speed sensor, the ECU 0 that refers to the output signal a of the vehicle speed sensor determines that the vehicle speed has become 0 at a time t1 that is earlier than the actual vehicle speed becomes 0 and the vehicle stops. Then, the counting of the grace time starts from the time point t1.

  Although the driver intends to stop the vehicle, when the brake pedal is depressed with the intention of adjusting the deceleration of the vehicle, the idle stop condition is satisfied, and the internal combustion engine is restarted at the time t2. Thereafter, at the time t3 when the driver steps on the brake pedal again, it is appropriate to execute the idle stop again. However, there is no history that the vehicle speed has been accelerated to a predetermined value during the period from time t2 to time t3. Even in such a case, the ECU 0 of the present embodiment extends the grace period from the time point t1 to the time point t4 so that the idle stop can be executed again, and excludes the acceleration history condition from the idle stop condition during the grace period. It is.

  When the vehicle deceleration after the time point t0 when the idle stop is started before the vehicle speed becomes 0 is relatively small, the grace time is the amount of brake operation by the driver after the time point t0 (the brake pedal depression amount or the master cylinder). The pressure is set to be longer when the pressure is relatively small and / or when the slope of the road surface after the time t0 is relatively large.

  For example, if the deceleration of the vehicle after time t0 is less than the threshold, the grace time is set to a longer time (8 seconds), and if it is greater than or equal to the threshold, the grace time is set to a shorter time (2 seconds). Similarly, if the amount of brake operation after time t0 is less than the threshold, the grace time is set to a longer time, and if it is greater than or equal to the threshold, the grace time is set to a shorter time. Alternatively, if the road slope after the time point t0 is equal to or greater than the threshold, the grace time is set to a longer time, and if less than the threshold, the grace time is set to a shorter time.

  The grace time may be set longer as the deceleration of the vehicle after time t0 is smaller, the brake operation amount is smaller, and / or the road slope is larger.

  Of course, if the time t3 when the driver re-depresses the brake pedal is later than the time t4 when the grace time elapses, the acceleration history condition is not excluded from the idle stop condition. Not.

  In the present embodiment, there is provided a control device 0 for a vehicle that implements an idle stop that stops the idle rotation of the internal combustion engine when the idle stop condition is satisfied, and one of the idle stop conditions is the restart of the nearest internal combustion engine. Acceleration history condition that there is a history that the vehicle speed has risen above the predetermined value after starting is included, but if the idle stop is started before the vehicle speed becomes 0, the vehicle speed has dropped to 0 or a value close to 0 The acceleration history condition is not included in the idle stop condition until the grace time elapses from the time when the vehicle is detected, and the grace time is set for the vehicle after starting the idle stop before the vehicle speed becomes zero. The control device 0 was configured to be variable according to the situation or the road surface condition.

  The control device 0 of the present embodiment sets the grace time longer when the vehicle deceleration after starting the idle stop before the vehicle speed becomes 0 is relatively small than when the vehicle deceleration is relatively large. If the brake operation amount by the driver after starting the idle stop before the vehicle speed becomes 0 is relatively small, the grace time is set longer than when the brake operation amount is relatively large, and / or When the downhill slope of the road surface where the vehicle after the start of the idle stop before the vehicle speed becomes zero is relatively large, the grace time is set longer than when the downhill slope of the road surface is relatively small.

  According to the present embodiment, when the vehicle is decelerated before the vehicle stops, the idle stop is started, and then the acceleration history condition is satisfied when the internal combustion engine is restarted by the driver releasing the brake pedal. It is possible to adjust the grace time excluded from the idle stop condition to a suitable length and restart the idle stop according to the driver's original intention to stop. In other words, the prohibition of idling stop against the will of the driver is lifted, and more idling stop opportunities can be secured, which contributes to further improvement in fuel efficiency.

  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 device a ... Vehicle speed signal d ... Brake switch (or stepping amount) signal g ... Tilt angle (or acceleration) signal h ... Master cylinder pressure signal

Claims (2)

A control device for a vehicle that performs an idle stop for stopping an idle rotation of an internal combustion engine when an idle stop condition is satisfied,
While one of the idle stop conditions includes an acceleration history condition that there is a history that the vehicle speed has risen above a predetermined value after the most recent restart of the internal combustion engine,
When the idling stop is started before the vehicle speed becomes zero, the acceleration history condition is changed to the idling stop condition from the time when it is detected that the vehicle speed is reduced to 0 or a value close to zero until the grace time elapses. Do n’t include it,
A control device in which the grace time is variable according to a vehicle condition or a road surface condition after an idle stop is started before the vehicle speed becomes zero. If the vehicle deceleration after starting the idle stop before the vehicle speed becomes 0 is relatively small, the grace time is set longer than when the vehicle deceleration is relatively large,
When the brake operation amount by the driver after starting the idle stop before the vehicle speed becomes 0 is relatively small, the grace time is set longer than when the brake operation amount is relatively large.
Alternatively, when the downhill slope of the road surface on which the vehicle is located after the start of the idle stop before the vehicle speed becomes 0 is relatively large, the grace time is set longer than when the downhill slope of the road surface is relatively small. The control device according to claim 1.

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