JP6651998B2 - Automatic engine stop control device - Google Patents

Description

  The present invention relates to an automatic stop control device that stops an engine of a vehicle when a predetermined stop condition is satisfied, and particularly to a setting of a delay time until the engine is stopped.

  2. Description of the Related Art Conventionally, in order to reduce fuel consumption in vehicles such as automobiles, there is a vehicle in which an engine is automatically stopped when traveling is stopped or when a predetermined stop condition is satisfied even before the stop. (So-called idle stop). For example, when the driver releases the accelerator pedal and the running speed of the vehicle becomes equal to or lower than a predetermined vehicle speed, the engine is stopped, and then, when predetermined restart conditions are satisfied, such as when the accelerator pedal is depressed again, the engine is stopped. Is started.

  Further, as an example, in the vehicle described in Patent Document 1, a delay time is provided between the stop condition is satisfied and the engine is stopped, and the length of the delay time is determined by the running state of the vehicle and the operation of the driver. By correcting according to the state, the annoyance of idle stop is reduced. For example, when the accelerator pedal is often depressed after the automatic stop or restart of the engine, it is estimated that the delay time is short, and the next delay time is extended.

JP 2014-084773 A

  However, if the idle stop is performed as described above and the engine is stopped immediately before or immediately after the vehicle stops, the sound of the fuel flowing in the fuel tank when the vehicle stops may cause the driver to feel uncomfortable. Was. That is, when the vehicle decelerates, the fuel that is biased to the front in the fuel tank flows rearward after the vehicle stops and collides with the inner surface of the tank, or is bounced up and collides with the ceiling surface, causing an abnormal situation in the vehicle interior. It produces sound.

  The noise generated in this way is not so loud that it will be hidden by the engine sound unless idle stop is performed, but if the engine stops immediately before or immediately after the vehicle stops due to idle stop, the driver will hear abnormal noise. And you will feel uncomfortable. It is conceivable to suppress the flow of fuel by adding a partition or the like inside the fuel tank, but this will increase the cost.

  Therefore, as a result of detailed examination of the generation of abnormal noise as described above, the inventors of the present invention have found that when the remaining amount of fuel in the fuel tank is large, the flowing mass becomes large, so that large abnormal noise is generated. At the same time, the time until the flow subsides becomes longer, so we focused on the fact that when the engine was stopped by idling stop, abnormal noises could easily reach the driver's ear.

  Based on such knowledge, an object of the present invention is to make the driver feel uncomfortable when the vehicle stops and restarts automatically when the vehicle stops and the noise generated by the flow of fuel in the fuel tank. The point is not to give.

  In order to achieve the above object, the present invention is directed to an automatic stop control device for stopping an engine of a vehicle in response to a predetermined stop condition being satisfied, wherein the stop condition is satisfied and the vehicle travels. Stop control means for stopping the engine after a predetermined delay time has elapsed after the speed has become equal to or less than the predetermined value, fuel amount detection means for detecting the remaining amount of fuel in the fuel tank, and fuel amount detection means A delay time changing unit that increases the delay time when the remaining amount is equal to or more than the predetermined amount, as compared with the case where the remaining amount is less than the predetermined amount.

  According to the above-described invention specifying matter, for example, when the driver releases the accelerator pedal while the vehicle is running, the vehicle speed decreases (or the vehicle stops), and when the engine stop condition is satisfied, the vehicle speed becomes a predetermined value (zero). After the delay time has elapsed since the following, the engine is stopped by the stop control means. At this time, once the vehicle decelerates, the fuel that is biased to the front in the fuel tank flows to the rear after the vehicle stops, and collides with the inside surface of the tank and the ceiling surface, causing abnormal noise in the vehicle interior. Will do.

  Such abnormal noise becomes loud when the remaining amount of fuel in the fuel tank is large, and the time until the noise is reduced also becomes long. However, according to the above-mentioned invention specifying matter, the remaining amount of fuel is equal to or more than a predetermined amount. If so, the delay time before stopping the engine becomes longer, so that abnormal noise is hidden in the engine sound, making it difficult for the driver to feel uncomfortable. On the other hand, if the remaining amount of fuel is small, the delay time becomes short, so that it is possible to stop the engine early and suppress fuel consumption.

  That is, it is possible to prevent the noise caused by the fuel flow in the fuel tank from giving the driver an uncomfortable feeling without significantly impairing the fuel consumption reduction effect due to the idle stop. Further, there is no need to add a partition in the fuel tank, and the cost does not increase.

  Note that the predetermined amount of the remaining fuel amount is an amount that does not cause excessive noise even if the fuel flows if the remaining amount is less than that, and may be set in advance for each vehicle type through experiments or the like. Good. If the remaining amount is equal to or more than the predetermined amount, the delay time may be lengthened as the amount increases, so that the delay time can be optimized for both reduction of fuel consumption and suppression of abnormal noise. .

  As described above, according to the engine automatic stop control device according to the present invention, the delay time from when the vehicle stops to when the engine is stopped is changed according to the remaining amount of fuel in the fuel tank. Therefore, the noise caused by the fuel flow in the fuel tank can be prevented from giving the driver an uncomfortable feeling without significantly impairing the fuel consumption reduction effect by the idle stop.

1 is a schematic configuration diagram of an engine and a control system according to an embodiment. FIG. 4 is an explanatory diagram showing a change in vehicle speed when the vehicle is decelerated or stopped, an engine state, a fuel consumption, and the like in association with each other. 4 is a flowchart illustrating an engine idle stop control routine. FIG. 3 is a diagram corresponding to FIG. 2 when idle stop control according to the embodiment is performed.

  Hereinafter, a case where the automatic stop control device according to the present invention is applied to a multi-cylinder gasoline engine mounted on an automobile (vehicle) will be described.

-Schematic configuration of engine-
FIG. 1 shows a schematic configuration of an engine 1 and a control system according to an embodiment. Each cylinder 2 accommodates a piston 12 so as to partition a combustion chamber 11, and is connected to a crankshaft 13 by a connecting rod 14. . A flywheel 15 (indicated by a phantom line) is attached to an end of the crankshaft 13, and a starter motor 16 is provided so as to be able to drive the flywheel. A crank angle sensor 61 for detecting a rotation angle of the crank shaft 13 is provided below the cylinder block 17.

  On the other hand, a cylinder head 18 is fastened to the upper end of the cylinder block 17 to close the upper end of each cylinder 2. An ignition plug 20 is disposed in the cylinder head 18 so as to face the inside of the cylinder 2. When a high voltage is supplied from an igniter 21 controlled by an ECU 100 described later, a spark discharge occurs. In addition, a water temperature sensor 62 that detects a cooling water temperature of the engine 1 is provided above the side wall of the cylinder block 17.

  Further, an intake passage 3 and an exhaust passage 4 are provided so as to communicate with the combustion chamber 11 of each cylinder 2. A portion downstream of the intake passage 3 (downstream of the intake flow) is an intake port formed in the cylinder head 18, and an intake valve 31 is provided at an opening facing the combustion chamber 11. Similarly, a portion on the upstream side (upstream side of the exhaust flow) of the exhaust passage 4 is an exhaust port, and an exhaust valve 41 is disposed at an opening thereof. The valve train 5 for operating the intake valve 31 and the exhaust valve 41 is provided in the cylinder head 18.

  As an example, the valve train 5 of the present embodiment includes an intake camshaft 51 that drives the intake valve 31 and an exhaust camshaft 52 that drives the exhaust valve 41. When the two camshafts 51 and 52 are driven by the crankshaft 13 via a timing chain (not shown) or the like, the intake valve 31 and the exhaust valve 41 are opened and closed at a predetermined timing. The intake camshaft 51 is provided with an electric VVT 53, and the opening / closing timing of the intake valve 31 is controlled by an ECU 100 described later.

  In the intake passage 3, an air cleaner 32, an air flow meter 63, an intake air temperature sensor 64 (built in the air flow meter 63), and an electronically controlled throttle valve 33 are arranged in this order from the upstream side. The throttle valve 33 is driven by a throttle motor 34 to adjust the intake air flow of the engine 1 by restricting the flow of intake air, and its opening (throttle opening) is controlled by an ECU 100 described later.

  In addition, an injector 35 for fuel injection is also provided for each cylinder 2 in the intake passage 3, and the injector 35 is controlled by an ECU 100 described later to inject fuel into the intake passage 3. . That is, the injector 35 for each cylinder 2 is connected to a common delivery pipe 36, and the fuel is supplied through the fuel supply pipe 37. The fuel supplied from the fuel tank 39 by the fuel pump 38 is supplied to the fuel supply pipe 37.

  The fuel tank 39 is, for example, a container made of resin and has a substantially rectangular parallelepiped shape. A fuel pump 38 is disposed inside the fuel tank 39 so as to be immersed in fuel. That is, as an example, the fuel pump 38 is a so-called in-tank type electric feed pump, and is assembled together with a float type fuel sensor 65 for operating a fuel filter and a fuel gauge. The fuel sensor 65 serves as a fuel amount detecting means for detecting the remaining amount of fuel in the fuel tank 39.

  Then, the fuel injected into the intake passage 3 from the injector 35 for each cylinder 2 is drawn into the cylinder 2 while being mixed with the intake air, and forms a combustible mixture in the combustion chamber 11. When this mixture is ignited by the ignition plug 20 at a predetermined timing and burned, the generated burned gas flows into the exhaust passage 4 and is purified by the catalytic converter 42. Note that an air-fuel ratio sensor 66 is provided upstream of the catalytic converter 42.

-ECU-
The ECU 100 is a microcomputer that includes a known electronic control unit (Electronic Control Unit) and includes a CPU, a RAM, a ROM, an input / output interface, and the like. The ROM stores a control program of the engine 1 and the like, and the RAM is a memory for temporarily storing a calculation result of the CPU, data input from each sensor, and the like. The backup RAM records data to be stored when the engine 1 is stopped.

  The ECU 100 is connected to the crank angle sensor 61, the water temperature sensor 62, the air flow meter 63, the intake air temperature sensor 64, the fuel sensor 65, the air-fuel ratio sensor 66, and the like as described above with reference to FIG. The ECU 100 is also connected to an accelerator opening sensor 67 for detecting an operation amount (accelerator opening) of an accelerator pedal 7 provided in the vehicle interior, and is used for controlling the operation of the engine 1 (not shown). Other sensors and switches are also connected.

  Then, the ECU 100 executes various control programs based on signals input from the various sensors, switches, and the like, to the engine 1 based on the accelerator opening, the load and rotation speed of the engine 1, the vehicle speed, and the like. Control of the ignition timing by the igniter 21, control of the throttle opening by the throttle motor 34 (that is, control of the intake air amount), control of the fuel injection by the injector 35, and the like so that the required torque is output. Do. The ECU 100 also controls the fuel pump 38 and the VVT 53.

  Further, the ECU 100 automatically stops the engine 1 when the running of the vehicle is stopped or when a predetermined stop condition is satisfied even while the vehicle is running (so-called idle stop). When a predetermined restart condition is satisfied, such as when the accelerator pedal 7 is depressed again, the starter motor 16 rotates the crankshaft 13 (cranking) to start the engine 1.

−Idle stop control−
By the way, when the engine 1 is stopped immediately before or immediately after the vehicle stops as in the present embodiment, the sound of the fuel flowing in the fuel tank 39 may give a feeling of strangeness to the driver. That is, as schematically shown in FIG. 2, for example, the driver returns the accelerator pedal 7 during traveling of the vehicle A (indicated by reference numerals only in FIGS. 2 and 4), and the vehicle speed V decreases. At the time of deceleration, as shown in the upper part (a) of the figure, the fuel is biased toward the front side (the right side in the figure) in the fuel tank 39, and a space is created on the rear side.

  Then, when the vehicle speed V decreases to the predetermined value V * and the stop condition of the engine 1 is satisfied (time t1), the engine 1 is stopped, and the fuel consumption (hatched) until the restart (to t3). However, when the vehicle A stops at the time t2, the fuel flows to the rear side (left side in the figure) in the fuel tank 39, as shown in the upper part (b) of the figure. The fuel collides with the inner surface of the rear tank (indicated by a star ☆ in the figure), and the fuel bounces up and collides with the ceiling surface. Generates abnormal noise.

  Further, the fuel once flowing to the rear side in the fuel tank 39 then flows again to the front side as shown in the upper part (c) of the figure, and collides with the front tank inner surface and the ceiling surface. (Indicated by an asterisk (*) in the figure), and abnormal noise is generated as described above. Since such abnormal noise is not so loud, the engine sound will be hidden unless idle stop is performed. However, in the present embodiment, the engine 1 is stopped immediately before the vehicle A stops as described above. Therefore, the driver hears the abnormal noise and feels strange.

  With respect to such a problem, in the present embodiment, attention has been paid to the fact that the magnitude and time of the abnormal noise caused by the flow of the fuel as described above depend on the remaining amount of the fuel in the fuel tank 39. That is, when the remaining amount of fuel is large, the flowing mass becomes large, the noise becomes large, and the time until the fluctuation in the liquid level becomes small, so that the time required for stopping the vehicle A for a relatively long time is relatively short. A loud noise is generated, and it is easy for the driver to feel uncomfortable.

  On the other hand, if the remaining amount of the fuel is small, even if the fuel flows and collides with the inner surface or the ceiling surface of the fuel tank 39 as described above, the noise generated thereby becomes small, and until the flow stops. Time is also shorter. Accordingly, in the present embodiment, when the remaining amount of fuel in the fuel tank 39 is equal to or more than the predetermined amount, the stop of the engine 1 is delayed for a while even if the stop condition is satisfied, and the engine sound is Abnormal noise is hidden.

  Hereinafter, the idle stop control routine of the engine 1 will be specifically described with reference to the flowchart shown in FIG. This control routine is executed at a predetermined timing (for example, at regular time intervals) while the ignition switch of the vehicle is on.

  First, in step S101 after the start shown in FIG. 3, it is determined whether or not the engine 1 is operating. This is determined, for example, from the value of the operation flag. If a negative determination is made while the engine is stopped (NO), the process proceeds to step S108 described later, while if an affirmative determination is made while the engine is running (YES), the process proceeds to step S102. Then, it is determined whether or not the stop condition of the engine 1 while the vehicle is running is satisfied. If a negative determination is made (NO), the process is temporarily terminated (END), and the operation of the engine 1 is continued.

  The stop condition of the engine 1 may be set so as to include, for example, that the accelerator is off (the accelerator opening is substantially equal to or less than a predetermined threshold value and substantially 0), and that the vehicle speed V is equal to or less than a predetermined value V *. . Then, the stop condition set in this way is satisfied, and if an affirmative determination is made in step S102 (YES), the process proceeds to step S103, in which whether the remaining amount of fuel in the fuel tank 39 is equal to or more than a predetermined amount is determined. Determine whether or not.

  The remaining amount of fuel is calculated by another routine based on a signal from the fuel sensor 65, and is stored (updated) in the RAM of the ECU 100. In addition, the predetermined amount of the remaining fuel amount is set in advance by an experiment or the like for each vehicle type as a small amount of the possibility that loud noise is generated even if the fuel flows if the remaining amount is smaller than the predetermined amount. I have. In step S103, the two are compared. If the determination is affirmative at a predetermined amount or more (YES), the process proceeds to step S104, where the delay time t until the engine is stopped is set to a relatively long time.

  In the present embodiment, the delay time Δt is set such that the longer the remaining amount of fuel that is equal to or more than the predetermined amount, the longer the time. This is because, as described above with reference to FIG. 2, the abnormal noise generated by the flow of the fuel increases as the remaining amount of the fuel increases, and the time during which the abnormal noise occurs increases. Therefore, for example, the delay time Δt may be set in advance as a map in accordance with the remaining amount of fuel by performing an experiment or the like for each vehicle type so that the abnormal sound is hidden in the engine sound.

  Preferably, the map may be set such that when the remaining amount of fuel is equal to or more than the predetermined amount, the delay time Δt increases as the deceleration of the vehicle increases. This is because the greater the deceleration of the vehicle, the greater the flow of fuel in the fuel tank 39. The deceleration of the vehicle may be calculated by differentiating the vehicle speed V. If the vehicle is equipped with a G sensor for detecting the acceleration in the front-rear direction, the deceleration is calculated from the output of the G sensor. You may make it.

  On the other hand, if the remaining amount of fuel is less than the predetermined amount and a negative determination is made in step S103 (NO), the process proceeds to step S105, and the delay time Δt is set to a relatively short time. If the remaining amount of fuel is less than the predetermined amount, there is a low possibility that a large noise is generated due to the flow of the fuel. Therefore, the delay time Δt can be set very short, and may be set to zero. In step S106 following either step S104 or S105, it is determined whether or not the delay time Δt has elapsed since the vehicle stopped.

  If this determination is a negative determination (NO), the process ends once (END). That is, even if the stop condition is satisfied, the engine 1 is not stopped until the delay time Δt has elapsed. On the other hand, if the delay time Δt has elapsed and an affirmative determination is made in step S106 (YES), the process proceeds to step S107 and the operation of the engine 1 is stopped. That is, the fuel injection by the injector 35 and the ignition by the igniter 21 are stopped, and the operation flag of the engine 1 is turned off.

  In step S108 following the above-described stop control, it is determined whether the restart condition of the engine 1 is satisfied. If an affirmative determination is made (YES), the routine proceeds to step S109, where the engine 1 is started. The restart condition may be set so as to include, for example, that the driver has performed a predetermined steering operation in addition to the brake off, the accelerator on, and the like.

In order to start the engine 1, the starter motor 16 is operated to start cranking, and at the same time, fuel injection by the injector 35 and ignition control by the igniter 21 are started. Then, combustion starts in any one of the cylinders 2 (first explosion), whereby the engine speed rises to a preset value, and if it is determined that the start is completed (YES in step S110), the process ends (END). )
By executing steps S102, S106, and S107 in the flow of FIG. 3, the ECU 100 determines that the delay condition Δt has elapsed after the stop condition of the engine 1 is satisfied and the vehicle speed V has become equal to or less than the predetermined value V *. By configuring stop control means for stopping the engine 1 and executing steps S103 to S105, a delay for increasing the delay time Δt when the remaining amount of fuel is equal to or more than a predetermined amount as compared with the case where the remaining amount is less than the predetermined amount. The time changing means is constituted.

  As described above, according to the engine automatic stop control device according to the present embodiment, when the vehicle speed V decreases during deceleration of the vehicle A as schematically shown in FIG. As described above, when the fuel is biased forward in the fuel tank 39, and when the vehicle speed V decreases to the predetermined value V *, the stop condition of the engine 1 is satisfied (time t1). Thereafter, when the vehicle A stops (time t2), the fuel flows backward in the fuel tank 39, and collides with the inner surface of the tank or the ceiling surface (indicated by a star in the figure).

  At this time, if the remaining amount of fuel in the fuel tank 39 is equal to or more than a predetermined amount, the fuel flowing as described above collides with the inner surface of the tank or the ceiling surface, so that a relatively loud noise is generated in the vehicle interior. However, in this case, the stop of the engine 1 is delayed until the delay time Δt elapses after the vehicle A stops. For this reason, the unusual noise in the vehicle interior is hidden by the engine sound, and it is difficult for the driver to feel uncomfortable.

  When the engine 1 stops operating after the delay time Δt has elapsed (time t3), the flow of the fuel in the fuel tank 39 as described above with reference to FIG. No loud noise is generated, and the driver does not feel uncomfortable. Then, after that, the engine 1 is restarted in response to, for example, a driver's brake or accelerator operation (time t4), and the vehicle A starts to start (time t5).

  As described above, in the present embodiment, by stopping the stop of the engine 1 for a while after the vehicle A stops (until time t3), the difference in the interior of the vehicle cabin due to the flow of the fuel in the fuel tank 39 is reduced. The sound can prevent the driver from feeling uncomfortable. Further, the fuel consumption (shown with hatching) can be reduced until the subsequent restart, that is, until the delay time Δt elapses (t3 to t4).

  In particular, in the present embodiment, the delay time Δt is changed in accordance with the remaining amount of fuel. As a result, the delay time Δt becomes longer, and it is possible to more reliably prevent the driver from feeling uncomfortable. On the other hand, if the remaining amount of the fuel is not too large, the delay time Δt becomes shorter accordingly, and if the remaining amount is less than the predetermined amount, the delay time Δt becomes very short, so that the fuel consumption can be sufficiently reduced. it can.

  That is, it is possible to prevent the noise caused by the fuel flow in the fuel tank 39 from giving the driver an uncomfortable feeling without significantly impairing the fuel consumption reduction effect due to the idle stop of the engine 1. For this reason, it is not necessary to newly provide a partition or the like in the fuel tank 39 so as to suppress the flow of the fuel, so that the cost does not increase.

-Other embodiments-
The present invention is not limited to the above-described embodiment, but also includes other various configurations. For example, in the above-described embodiment, the stop condition of the engine 1 includes that the vehicle speed V is equal to or less than a threshold value (V * ≒ 0), and the operation of the engine 1 is stopped before the vehicle stops. This is only an example, and the engine 1 may be stopped after the vehicle stops, for example.

  Further, in the above-described embodiment, the engine 1 is not stopped until the delay time Δt elapses after the vehicle stops (vehicle speed V = 0). This may be performed until the delay time Δt elapses after the value becomes less than the value. In other words, the threshold value V * of the vehicle speed V included in the stop condition of the engine 1 and the predetermined value of the vehicle speed V at which the delay time Δt starts may be the same or different.

  Further, in the above embodiment, when the remaining amount of fuel in the fuel tank 39 is equal to or more than the predetermined amount, the stop of the engine 1 is delayed, and the delay time Δt is changed according to the remaining amount of fuel. However, when the remaining amount of fuel is equal to or more than a predetermined amount, a fixed delay time Δt may be set regardless of the remaining amount.

  Further, in the above-described embodiment, the case where the present invention is applied to the multi-cylinder gasoline engine 1 mounted on an automobile (vehicle) is described as an example. However, the present invention is not limited thereto. The present invention can be applied to an engine, an alcohol engine, a gas engine, and the like, and can be applied to a hybrid system including an electric motor for traveling in addition to the engine.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a vehicle in which an engine is idle-stopped, since an abnormal noise generated by a flow of fuel in a fuel tank accompanying a stop does not give a sense of incongruity to a driver. Is high.

A vehicle 1 engine 39 fuel tank 65 fuel sensor (fuel amount detecting means)
100 ECU (stop control means, delay time changing means)

Claims (1)

An automatic stop control device configured to stop the engine of the vehicle in response to satisfaction of a predetermined stop condition,
Stop control means for stopping the engine after a predetermined delay time has elapsed since the stop condition was satisfied and the traveling speed of the vehicle became equal to or less than a predetermined value,
Fuel amount detection means for detecting the remaining amount of fuel in the fuel tank;
An automatic stop control device for an engine, comprising: a delay time changing unit configured to increase the delay time when the detected remaining amount of fuel is equal to or more than a predetermined amount, as compared with a case where the detected remaining amount is less than a predetermined amount. .

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