JP2016166584A - Automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make rotation speed of an engine properly converge at a target rotation speed when a demand for restarting the engine is made during an idling stop.SOLUTION: In an automobile 100, when a demand for restarting an engine 110 is made in a state of an idling stop, a target rotation speed of the engine after restarting is derived, a target generation load of a power generator is derived based on the target rotation speed, and by referring to a generation load correction map, a correction value is derived based on the target generation load and oil temperature. The power generator is controlled with a generation load obtained by adding the correction value to the target generation load, and the engine is controlled to reach the target rotation speed. When a rotation speed of the engine converges, by referring to a correction value update map, an update correction value is derived based on a difference between an actual rotation speed of the engine until convergence of the rotation speed after restarting and the target rotation speed to update the generation load correction map.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an automobile equipped with an idle stop function.

  In recent years, in order to reduce fuel consumption and exhaust gas, vehicles such as automobiles automatically stop the engine when the vehicle stops due to traffic lights or traffic jams, and restart the engine when it is necessary to operate the engine. Various techniques for the so-called idle stop function have been proposed.

  For example, when the inter-vehicle distance from the preceding vehicle is less than the set value, or when the signal color emitted from the traffic light is red or yellow and the speed of the host vehicle is 0 (zero), that is, at an intersection Idle stop when stopping for waiting. And the technique which restarts an engine when the distance between vehicles becomes more than a setting value or the color of the traffic light changed to blue is shown (for example, patent document 1).

  If the engine is restarted when the idle stop is performed in this way, the engine speed increases too much and the actual engine speed overshoots the target engine speed (target engine speed), causing the driver to feel uncomfortable. May give. Therefore, a technique is known in which when the engine speed is exceeded when the target rotational speed is exceeded, the motor is caused to function as a generator to suppress the rotation increase (for example, Patent Document 2).

Japanese Patent Laid-Open No. 7-4284 Japanese Patent No. 3649031

  As described above, by using the generator when the engine is restarted, it is possible to suppress the engine speed from being excessively increased. However, if the power generation load of the power generator is not taken into consideration and the function is merely performed as a power generator, an overshoot may remain, or the power generation load may be applied too much to reach the target rotational speed. In addition, even if the power generation load can be derived uniformly according to the target rotational speed, the derived power generation load can avoid overshoot due to individual differences of each engine or generator for each vehicle and aging degradation. There is a risk that it will deviate from the original power generation load and the overshoot cannot be suppressed appropriately.

  In view of such a problem, an object of the present invention is to provide an automobile capable of appropriately converging the engine speed to a target engine speed when the engine is requested to be restarted at an idle stop.

  In order to solve the above-described problems, a vehicle according to the present invention includes a power generation load correction map in which a computer associates a target power generation load of a generator and an engine oil temperature with a correction value, and a difference and update of an engine speed. A correction value update map in which correction values are associated with each other is held, and when there is an engine restart request in an idle stop state, a rotation speed deriving unit for deriving a target rotation speed of the engine after restart, and a target rotation speed The power generation load deriving unit for deriving the target power generation load of the generator based on the generator, the power generation load correction map, and the target power generation load derived by the power generation load deriving unit and the correction based on the oil temperature detected by the oil temperature sensor A correction value deriving unit for deriving a value, a generator control unit for controlling the generator with a power generation load obtained by adding a correction value to the target power generation load, and an engine control unit for controlling the engine so as to achieve a target rotational speed. When the engine speed has converged, the correction value update map is referred to, and an update correction value is derived based on the difference between the actual engine speed and the target engine speed until the engine speed converges after the restart. And it functions as a correction value update unit that updates the power generation load correction map with the update correction value.

  The generator may be an alternator coupled to the engine.

  The automobile may be a hybrid vehicle having an engine and an electric motor as drive sources, and the generator may be an electric motor.

  According to the present invention, the engine speed can be appropriately converged to the target speed when the engine is requested to be restarted at an idle stop.

It is a functional block diagram showing a schematic configuration of an automobile. It is a timing chart for explaining restarting operation of an engine in idle stop. It is explanatory drawing for demonstrating a power generation load correction map. It is explanatory drawing for demonstrating operation | movement of a correction value update part. It is explanatory drawing for demonstrating a correction value update map.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  In a vehicle such as an automobile, power is obtained by a driving mechanism such as an engine, and steering or braking of the vehicle is executed by a driver's operation through a steering wheel or a brake pedal. In addition, for the purpose of reducing fuel consumption and exhaust gas, the engine is automatically stopped when the vehicle stops due to a signal waiting or traffic jam, and the engine is started when there is a request to restart the engine while the engine is stopped. Vehicles equipped with an idle stop function are also popular.

  If the engine is restarted when the idle stop is executed in this way, the engine speed increases too much and the actual engine speed overshoots the target engine speed, and the vehicle starts to run faster than the driver intended. There is a possibility that such a sense of incongruity may be given or that comfortable driving performance may be impaired. In order to avoid such overshoot, for example, it may be possible to control the torque so that it does not increase according to the engine speed increase mode, but the control operation becomes complicated and energy is wasted. Will end up. In addition, although it is conceivable to increase the power consumption of the auxiliary machine or the like, as a practical problem, it is difficult to freely control the power consumption of the air conditioner or the power steering.

  Therefore, in the present embodiment, by appropriately controlling the power generation load (duty) of a generator such as an alternator connected to the engine, the engine speed is set to the target speed when the engine is requested to be restarted at idle stop. The goal is to converge properly. Hereinafter, the automobile 100 that realizes such an idle stop function will be described in detail.

(Car 100)
FIG. 1 is a functional block diagram illustrating a schematic configuration of the automobile 100. The automobile 100 includes an engine 110, an alternator 112, a battery 114, a vehicle load 116, a control unit 118, a map holding unit 120, a shift position sensor 122, an accelerator pedal sensor 124, a brake pedal sensor 126, a vehicle speed sensor 128, and an oil temperature sensor 130. Consists of including.

  The engine 110 is a drive source of the automobile 100 and rotates drive wheels of the automobile 100 via a clutch and a transmission (not shown). The alternator 112 is a generator that is directly or indirectly connected to the rotating shaft of the engine 110 via a pulley mechanism, and generates electric power using the rotation of the engine 110 as a driving source. Specifically, the field current is supplied to the field coil of the alternator 112 by the rotation of the engine 110 to generate an induced current of a three-phase alternating current. Then, the field current of the field coil is adjusted through a regulator or the like, and the generated voltage (output voltage) is controlled to 14 V, for example.

  The alternator 112 executes engine power generation that actively generates torque by inputting torque (power generation torque) from the engine 110, and regenerative power generation that generates power by inputting torque (braking torque) from the drive wheels or the transmission side. Is done. In the present embodiment, when the engine 110 is restarted at idle stop, the alternator 112 is caused to generate electric power to prevent the engine 110 from being blown up excessively by a power generation load based on the power generation function. In this way, the alternator 112 is used as a means for avoiding the overshoot of the rotational speed, so that the power generation load can be controlled with high resolution, and the energy consumed as the power generation load is charged in the battery 114 described later. This is because useless energy loss does not occur.

  The battery 114 is connected to the alternator 112 and accumulates (charges) the electric power generated by the alternator 112. Further, when electric power is required by the vehicle load 116 such as the engine 110 or an auxiliary machine, for example, when electric power is supplied to the starter when the engine 110 is started, the battery 114 uses the accumulated electric power for the engine 110 or the vehicle load 116. Is supplied (discharged).

  The control unit 118 is configured by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing a program, a RAM as a work area, and the like, and performs overall control of the entire automobile 100. In the present embodiment, the control unit 118 includes an engine operation request unit 150, an engine control unit 152, a rotation speed deriving unit 154, a power generation load deriving unit 156, a correction value deriving unit 158, a generator control unit 160, and a correction value updating unit 162. Also works.

  The map holding unit 120 is connected to the control unit 118 and holds each map required by the control unit 118. For example, the map holding unit 120 includes a power generation load correction map in which the target power generation load (target power generation load) of the alternator 112 and the temperature of the lubricating oil of the engine 110 (hereinafter simply referred to as oil temperature) are associated with correction values. In addition, a correction value update map or the like in which the difference between the rotation speeds of the engine 110 and the update correction value are associated is held. The power generation load correction map and the correction value update map will be described in detail later.

  In addition, the control unit 118 has the vehicle transmission shift range in the forward range (D range), reverse range (R range), neutral range (N range), or parking range (P range). A shift position sensor 122 that detects the amount of depression of the accelerator pedal (not shown) (hydraulic pressure), an accelerator pedal sensor 124 that detects the amount of depression (hydraulic pressure) of the brake pedal (not shown), and the speed of the automobile 100 Sensors such as a vehicle speed sensor 128 that detects (the number of revolutions of the engine 110) and an oil temperature sensor 130 that detects the temperature of the lubricating oil of the engine 110 are connected, and the control unit 118 can capture the detection signals of each sensor. it can.

(Operation of control unit 118)
Engine operation request unit 150 requests start and stop of engine 110 based on the running state of automobile 100 and the like. First, the engine operation request unit 150 determines whether or not the engine 110 can be stopped while the automobile 100 is traveling.

  For example, the engine operation request unit 150 detects that the shift range detected by the shift position sensor 122 is located in any one of “D range”, “N range”, and “P range”, and is detected by the accelerator pedal sensor 124. The amount of depression of the accelerator pedal is less than a predetermined oil pressure (release), the amount of depression of the brake pedal detected by the brake pedal sensor 126 is greater than or equal to the predetermined oil pressure, and the vehicle speed detected by the vehicle speed sensor 128 is less than the predetermined speed (stops). If it is, the vehicle 100 is recognized as being stopped, and the engine control unit 152 is requested to stop the engine 110 for idling stop.

  Further, the engine operation request unit 150 has the shift range detected by the shift position sensor 122 while the engine 110 is stopped, being located in any one of “D range”, “N range”, and “P range”. If the amount of depression of the brake pedal detected by the brake pedal sensor 126 is less than a predetermined oil pressure (release) and the amount of depression of the accelerator pedal detected by the accelerator pedal sensor 124 is equal to or greater than the predetermined oil pressure, it is recognized that the automobile 100 starts to travel. Then, the engine control unit 152 is requested to restart the engine 110.

  Further, even if the engine operation request unit 150 does not recognize that the automobile 100 starts to travel, when the capacity of the battery 114 becomes less than a predetermined value or the load of the air conditioner becomes equal to or higher than the predetermined value while the engine 110 is stopped, In order to cover the power, the engine control unit 152 is requested to restart the engine 110.

  FIG. 2 is a timing chart for explaining the restart operation of the engine 110 at the idle stop. 2A shows the rotational speed of the engine 110, and FIG. 2B shows the power generation load of the alternator 112.

  Engine control unit 152 also functions as an ECU (Engine Control Unit), and controls starting and stopping of engine 110 based on a request from engine operation requesting unit 150. Here, the engine 110 has been started in a running state in which the engine 110 is operated with a load on the engine 110 and an idle state in which the throttle valve is fully closed and the engine 110 is operated in a no-load state. There is. In addition, the state where the engine 110 is stopped indicates a state where the engine 110 is automatically stopped by cutting off the energization of the ignition circuit of the engine 110. When the engine 110 is started from such a stopped state of the engine 110, the starter and the engine ignition circuit are energized to restart the engine 110.

  The engine control unit 152 quickly stops the engine 110 when the engine operation request unit 150 requests the engine 110 to be stopped while the engine 110 is operating. Then, the target rotational speed of the engine 110 indicated by a broken line in FIG. 2A becomes 0, and accordingly, the actual rotational speed of the engine 110 indicated by a solid line also changes to 0. At this time, the target power generation load of the alternator 112 indicated by a broken line in FIG. 2B and the actual power generation load (actual power generation load) of the alternator 112 indicated by a solid line temporarily increase due to regenerative power generation. When the engine 110 is completely stopped, the target power generation load returns to a steady value, and the actual power generation load becomes zero as the engine 110 stops.

  The engine control unit 152 restarts the engine 110 when the engine operation requesting unit 150 requests the engine 110 to be restarted while the engine 110 is stopped (in an idle stop state). Then, as shown in FIG. 2A, a predetermined value is set for the target engine speed of the engine 110, and the actual engine speed of the engine 110 increases accordingly. At this time, as shown in FIG. 2B, the actual power generation load also increases based on the target power generation load of the alternator 112.

  When there is a restart request for engine 110 in the idling stop state in which engine 110 is stopped, rotation speed deriving unit 154 derives the target rotation speed of engine 110 after the restart. The target rotational speed is determined to be a predetermined value according to the oil temperature when the engine 110 is restarted, the remaining amount of the battery 114, and the like. Since various existing techniques can be applied to the target rotational speed derivation process, detailed description thereof is omitted here.

  When there is a restart request of the engine 110 in the idling stop state, the power generation load deriving unit 156 determines the target power generation of the alternator 112 based on the target rotational speed derived by the rotational speed deriving unit 154 and the capacity of the battery 114 at that time. Deriving the load. Since various existing technologies can be applied to the target power generation load deriving process, detailed description thereof is omitted here.

  When there is a restart request of the engine 110 in the idle stop state, the correction value deriving unit 158 refers to the power generation load correction map from the map holding unit 120, and the target power generation load derived by the power generation load deriving unit 156 and the oil temperature sensor A correction value is derived based on the oil temperature detected by 130.

  FIG. 3 is an explanatory diagram for explaining the power generation load correction map. As described above, the power generation load correction map is a map in which correction values are associated with the target power generation load of the alternator 112 and the oil temperature of the engine 110. Therefore, if the target power generation load and the oil temperature are determined, the correction value is uniquely determined. Here, since the correction value is a value for correcting the target power generation load, “+” is added to the correction value for increasing the target power generation load, and “−” is added to the correction value for decreasing the target power generation load. For example, when the target power generation load is 60% (duty) and the oil temperature is 80 ° C., the correction value is + 2% as shown by a thick frame in FIG.

  Here, the oil temperature is used as a parameter of the power generation load correction map because there is a correlation between the target rotational speed of the engine 110 and the temperature of the cooling water of the engine 110 (hereinafter simply referred to as water temperature), and the water temperature and the oil temperature. This is because there is a correlation with temperature. Therefore, deriving the correction value according to the oil temperature leads to an appropriate correction value according to the target rotational speed.

  When there is a restart request of the engine 110 in the idle stop state, the generator control unit 160 adds the correction value derived by the correction value deriving unit 158 to the target power generation load derived by the power generation load deriving unit 156. The alternator 112 is controlled by (actual power generation load). For example, as described above, when the target power generation load is 60% and the oil temperature is 80 ° C., the correction value is + 2%, so the actual power generation load is 62% (60% + 2%). Then, as shown in FIG. 2B, the generator control unit 160 sets the actual power generation load to 62% by adjusting the regulator of the alternator 112, and actively performs engine power generation. The power generated in this way is charged in the battery 114. Therefore, the higher the power generation load is selected, the greater the power charged in the battery 114.

  At this time, the engine control unit 152 starts the engine 110 in response to a restart request of the engine 110 in the idle stop state, and controls the engine 110 so that the target rotation number derived by the rotation number deriving unit 154 is obtained. At this time, if the actual power generation load of the alternator 112 is an appropriate value, the rotational speed of the engine 110 can be appropriately converged to the target rotational speed as shown in FIG.

  Further, when the rotation speed of the engine 110 converges, the generator control unit 160 changes the actual power generation load from 62% including the correction value to 60% which is the target power generation load, as shown in FIG. return. In this way, it is possible to shift to steady power generation after the rotational speed of the engine 110 has converged.

  When the rotational speed of the engine 110 converges, for example, when the fluctuation of the rotational speed of the engine 110 settles within a range of ± 10 rpm with respect to the target rotational speed, the correction value update unit 162 refers to the correction value update map, The actual rotational speed of the engine 110 detected by the vehicle speed sensor 128 from the start until the rotational speed of the engine 110 converges (hereinafter simply referred to as the actual rotational speed), for example, the peak value of the actual rotational speed and the rotational speed deriving unit An update correction value is derived based on the difference from the target rotational speed derived by 154, and the power generation load correction map is updated with the update correction value.

  FIG. 4 is an explanatory diagram for explaining the operation of the correction value updating unit 162. For example, in FIG. 4A, the actual rotational speed of the engine 110 overshoots the target rotational speed. This indicates that when the engine 110 is restarted, the actual power generation load corrected by the correction value is applied, but the applied power generation load of the alternator 112 is still insufficient. However, if the power generation load is uniformly applied, this time, there is a possibility that the power generation load is applied too much and the arrival at the target rotational speed is delayed. Therefore, the correction value updating unit 162 maintains the transition of the actual rotational speed of the engine 110 after restarting the engine 110, and when the rotational speed of the engine 110 converges, as shown in FIG. The peak value of the actual rotational speed is acquired based on the transition up to. Then, based on the difference between the acquired peak value and the target rotation speed, an update correction value for updating the correction value is derived, and the power generation load correction map is updated with the update correction value.

  In addition, although the case where the actual rotation speed of the engine 110 has overshooted the target rotation speed has been described here, the case where the arrival at the target rotation speed is delayed due to excessive power generation load is similarly described. An update correction value can be derived based on the difference between the delayed value and the target rotational speed in the actual rotational speed. Here, the peak value of the actual rotational speed is described as an object of the difference. However, the present invention is not limited to this, and any deviation between the actual rotational speed and the target rotational speed may be used. For example, FIG. As indicated by hatching in b), the update correction value may be derived based on the area of the region surrounded by the actual rotational speed locus and the target rotational speed transition.

  FIG. 5 is an explanatory diagram for explaining the correction value update map. As shown in FIG. 5A, the correction value update map is a map in which the update correction value is associated with the difference in the rotational speed of the engine 110. Therefore, if the difference in rotation speed (difference between the peak value and the target rotation speed) is determined, the update correction value is uniquely determined. Here, since the update correction value is a value that further corrects the correction value, “+” is added to the update correction value that increases the correction value, and “−” is added to the update correction value that decreases. For example, when the target power generation load is 60% (duty), the oil temperature is 80 ° C., and the correction value at that time is + 2%, the update correction value is as shown in FIG. As indicated by a thick frame in 5 (a), it is + 1%. Then, as indicated by a thick frame in FIG. 5 (b), the correction value update unit 162 corresponds to the correction value + 2% when the target power generation load is 60% (duty) and the oil temperature is 80 ° C. in the power generation load correction map. Then, the power generation load correction map is updated by overwriting + 3% obtained by adding the update correction value + 1%. Therefore, next time, when the target power generation load is 60% and the oil temperature becomes 80 ° C., the generator control unit 160 performs engine power generation with the actual power generation load set to 63%.

  With this configuration, when the target power generation load is 60% and the oil temperature is 80 ° C., the target power generation load is corrected with a correction value of + 3% that is greater than + 2%, and the power generation load is sufficiently high such as 63%. Thus, overshoot is appropriately avoided.

  As described above, in the present embodiment, an appropriate power generation load corresponding to the target power generation load and the oil temperature can avoid overshoot of the rotational speed, and the vehicle of the engine 110 and the alternator (generator) 112 can be avoided. Even when the appropriate power generation load fluctuates due to individual differences and aging deterioration, the engine 110 at idle stop is updated by updating to an appropriate correction value in real time according to the behavior of the actual rotation speed of the engine 110. When the restart is requested, the engine 110 can be properly converged to the target engine speed.

  Also provided are a program that causes the computer to function as the automobile 100, and a storage medium such as a computer-readable flexible disk, magneto-optical disk, ROM, CD, DVD, or BD on which the program is recorded. Here, the program refers to data processing means described in an arbitrary language or description method.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the coarse resolution is shown as the power generation load correction map and the correction value update map for easy understanding. However, in reality, the map holding unit 120 allows a finer resolution as long as the memory capacity is allowed. Can be shown. Furthermore, the difference (fraction) between the numerical value set in this way and the actual numerical value may be derived by linear interpolation or the like. Needless to say, the numerical values set in the power generation load correction map and the correction value update map are not limited to those shown in FIGS. 3 and 5 and can be arbitrarily set.

  In the above-described embodiment, the automobile 100 using the engine 110 has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to a hybrid car having two drive sources of the engine 110 and an electric motor. In this case, the motor 110 provided in addition to the alternator 112 is used as a generator, and the power generation load is controlled. An effect of appropriately converging on the rotation speed can be obtained.

  The present invention can be used for an automobile equipped with an idle stop function.

100 Car 110 Engine 112 Alternator (generator)
114 Battery 120 Map holding unit 152 Engine control unit 154 Rotational speed deriving unit 156 Power generation load deriving unit 158 Correction value deriving unit 160 Generator control unit 162 Correction value updating unit

Claims (3)

Computer
A power generation load correction map in which the target power generation load of the generator and the engine oil temperature and the correction value are associated with each other, and a correction value update map in which the difference between the rotation speeds of the engine and the update correction value are associated with each other are retained.
When there is a request to restart the engine in the idle stop state,
A rotational speed deriving unit for deriving a target rotational speed of the engine after restart;
A power generation load deriving unit for deriving a target power generation load of the generator based on the target rotational speed;
With reference to the power generation load correction map, a target power generation load derived by the power generation load deriving unit, a correction value deriving unit for deriving the correction value based on the oil temperature detected by the oil temperature sensor,
A generator control unit for controlling the generator with a power generation load obtained by adding the correction value to the target power generation load;
An engine control unit that controls the engine to achieve the target rotational speed;
Function as
When the engine speed converges,
With reference to the correction value update map, the update correction value is derived based on the difference between the actual engine speed and the target engine speed after the restart until the engine speed converges. A correction value update unit for updating the power generation load correction map;
A car that functions as a car.   The automobile according to claim 1, wherein the generator is an alternator coupled to the engine. The automobile is a hybrid car having the engine and an electric motor as a drive source,
The automobile according to claim 1, wherein the generator is the electric motor.

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