JP2006275009A - Motor controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel economy by reducing a filter-forced regeneration time for a hybrid vehicle using a diesel engine. <P>SOLUTION: This motor controller of the hybrid vehicle comprises an output allocation determination means 15 determining output allocations to a diesel engine 1 and a motor 2 against a requested drive force, a filter 33 collecting particulates in the exhaust gases of the diesel engine 1, and a forced regeneration means 35 forcibly regenerating the filter 33. The output allocation determination means 15 is formed to increase the output allocation to the diesel engine 1 and decrease the output allocation to the motor 2 while the filter 33 is forcibly regenerated and the vehicle is running. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device for a hybrid vehicle, and more particularly to control of a motor during forced regeneration of a filter that collects particulates in exhaust gas.

  Conventionally, a hybrid vehicle or a hybrid electric vehicle in which a driving force of a vehicle is obtained by combining an internal combustion engine (engine) and an electric motor (motor) has been developed and put into practical use. In such a hybrid vehicle, a series hybrid vehicle that uses the engine exclusively as a motor power supply source (generator), or mechanically connecting the engine output shaft and the motor output shaft, 2. Description of the Related Art A parallel hybrid vehicle that can drive a drive wheel is known.

Among these, in the parallel hybrid vehicle, the required drive torque is obtained from the load information such as the accelerator depression amount of the driver and the engine speed, and the output distribution between the engine and the motor is set from the remaining battery capacity. ing.
By the way, it is conceivable to apply a diesel engine as an engine of a parallel hybrid vehicle. In this case, an oxidation catalyst (DOC) and a particulate collection filter (hereinafter simply referred to as a filter) are provided in the exhaust passage of the diesel engine, and particulate matter (PM) contained in the exhaust gas is filtered. A technique is known in which the filter is continuously regenerated by oxidizing (combusting) PM collected and deposited on the filter. In the following, the particulate matter is expressed as PM, which has the same meaning as soot, particulate and soot.

In such a technique, for example, a differential pressure sensor that detects a pressure difference between the inlet and the outlet of the filter is provided, and if the differential pressure detected by the differential pressure sensor exceeds a predetermined value, the filter is clogged. Therefore, the filter is forcedly regenerated.
During forced regeneration, additional fuel injection (post fuel injection) is performed at the later stage of the expansion stroke or at the beginning of the exhaust stroke, and unburned fuel (HC; hydrocarbon) of the additional fuel is oxidized (combusted) with an oxidation catalyst. And the exhaust gas temperature flowing into the filter is raised by the reaction heat at this time. The exhaust gas flowing into the filter is heated to cause the PM in the filter to self-ignite to burn the PM, thereby forcibly regenerating the filter (first prior art).

In Patent Document 1, in a hybrid vehicle having a normal travel mode that travels while switching between engine travel and motor travel and a special travel mode that travels only by the engine, the travel mode is set when the catalyst is not activated. A technique for forcibly switching to a special traveling mode is disclosed. Such control makes it possible to quickly increase the catalyst temperature when the catalyst temperature decreases (second conventional technique).
JP 2001-115869 A

  However, in the first prior art described above, if the filter is forcibly regenerated when running mainly with the motor (motor output distribution> engine output distribution), the forced regeneration is suppressed. The forced regeneration time becomes longer and the fuel consumption deteriorates. This is because when the vehicle is driven mainly, the engine is in a low load operation or an idle operation, the fuel injection amount is reduced, and even if post fuel injection is performed, the total fuel injection amount This is because a sufficient amount of heat cannot be given to the filter.

Further, in the technique of Patent Document 1 (second conventional technique), when the catalyst is not activated, the traveling mode is forcibly switched to the special traveling mode in which only the engine travels, so the output of the motor becomes zero. For this reason, there is still a problem that the fuel consumption of the engine deteriorates.
The present invention has been developed to meet such demands, and an object of the present invention is to provide a motor control device for a hybrid vehicle that reduces the forced regeneration time of the hybrid vehicle and improves fuel efficiency. .

  For this reason, the motor control device for a hybrid vehicle according to the present invention includes a diesel engine mounted on a vehicle, a motor mounted on the vehicle, a battery connected to the motor in a chargeable / dischargeable manner, and travel of the vehicle. Output distribution determining means for determining the output distribution of the diesel engine and the motor for the required driving force based on the required driving force and the state of charge of the battery; and particulate matter in the exhaust gas of the diesel engine. And a forced regeneration means for forcibly regenerating the filter, and the output distribution determination means is when the vehicle is running and the forced regeneration by the forced regeneration means is being executed. While increasing the output distribution of the diesel engine for the required driving force, the output of the motor for the driving force It is characterized by reducing the partial (claim 1).

The output distribution determining means reduces the output distribution of the diesel engine with respect to the driving force when the vehicle is running and the execution of the forced regeneration is finished, and The motor output distribution is increased (claim 2).
Further, the output shaft of the diesel engine is connected to the output shaft of the motor via a clutch (claim 3).

  According to the hybrid vehicle motor control device of the present invention, in the forced regeneration during traveling, the output distribution of the diesel engine increases, so that the fuel injection amount does not extremely decrease, and the particulate matter is removed by forced regeneration. Is promoted. For this reason, forced regeneration is completed at an early stage, and fuel efficiency is improved. At this time, since the motor output distribution is reduced, the vehicle driving force is not affected.

  Further, in the forced regeneration during traveling, when the forced regeneration is finished, the output distribution of the diesel engine is quickly reduced, so that the engine noise is reduced. At this time, since the torque distribution of the motor output is increased, the vehicle driving force is not affected.

  Hereinafter, a motor control apparatus for a hybrid vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a power train of a vehicle to which the present invention is applied. As shown in the figure, this vehicle is a parallel hybrid vehicle (HEV) using an engine 1 and an electric motor (or a motor / generator, hereinafter simply referred to as a motor) 2 as a drive source 8. The vehicle is driven by the total output of 2.

  A clutch 3 that can connect and disconnect the driving force between the engine 1 and the motor 2 is provided between the engine 1 and the motor 2. On the output side of the motor 2, a transmission 4 that changes the output rotation speed from the engine 1 and / or the motor 2 is provided. That is, in this vehicle, the devices are arranged in series in the order of the engine 1, the clutch 3, the motor 2, and the transmission 4. The driving force output from the transmission 4 is transmitted to the drive wheels 7.

Further, a chargeable / dischargeable battery 6 is connected to the motor 2 via an inverter 5, and the operation state of the motor 2 is controlled by controlling the operation of the inverter 5.
With such a configuration, by driving the motor 2 with the clutch 3 connected, it is possible to travel while assisting the driving force of the engine 1 with the driving force of the motor 2. Further, by causing the motor 2 to function as a generator by the inverter 5, the battery 6 is charged by generating power with the driving force of the engine 2, or the electric power is regenerated by applying a regenerative brake equivalent to the engine brake. Can do. In addition, it is also possible to drive the driving wheel 7 only by the driving force of the motor 2 by the motor 2 being powered by receiving power supply from the battery 6 with the clutch 3 disconnected.

  By the way, in this embodiment, an automatic transmission is applied as the transmission 4. This automatic transmission 4 is a stepped automatic transmission that switches the current shift stage so as to be the target shift stage set in the shift map. The automatic transmission is configured to switch a gear position by operating a plurality of actuators (not shown) based on a manual transmission.

Therefore, the transmission 4 is provided with a gear shift unit (GSU) 9 having a plurality of actuators (not shown) (see FIG. 2). In addition to such a transmission, a manual transmission may be used as the transmission, or an automatic transmission combining a torque converter and a planetary gear mechanism may be used.
The clutch 3 is an automatic clutch that automatically engages and disengages the clutch when the gear position is changed. The clutch actuator (not shown) operates in cooperation with the GSU 9 so that the clutch 3 is engaged and disengaged. It has become so. When an automatic transmission having a torque converter is applied to the transmission 2, the clutch 3 can be omitted.

In the present embodiment, the engine 1 is configured as a diesel engine, and the output torque of the engine 1 is controlled by controlling the drive time (that is, the fuel injection amount) of the injector 10 (see FIG. 2). It is like that.
Next, the main part of the present invention will be described with reference to FIG. 2. In the exhaust passage 31 of the diesel engine 1 described above, an oxidation catalyst 32 that oxidizes components in exhaust gas in order from the upstream side and PM (carbon in exhaust gas). And a filter 33 for collecting (particulate matter mainly composed of C).

Here, during normal travel, the oxidation catalyst 32 oxidizes NO in the exhaust gas to NO ₂ and supplies this NO ₂ to the filter 33 as an oxidant. In the filter 33, the NO ₂ and PM react with each other to burn the PM, and the filter 33 can be continuously regenerated.
Further, at the time of forced regeneration, there is a function of oxidizing unburned fuel (HC) in the exhaust gas (combustion) and supplying the exhaust gas heated to high temperature by the reaction heat at this time to the filter 33. Then, by raising the temperature of the exhaust gas flowing into the filter 33, the PM in the filter 3 is self-ignited to burn the PM, and the filter 33 is forcibly regenerated.

  Here, although not shown in detail, the filter 33 is formed of a porous material as a whole, and includes a first passage opened on the upstream side and closed on the downstream side, and a second passage closed on the upstream side and opened on the downstream side. Are alternately arranged adjacent to each other. As a result, the exhaust gas supplied to the filter 33 flows from the first passage into the second passage through the porous wall, and at this time, PM in the exhaust gas is collected in the wall. Yes. A differential pressure sensor 34 that detects a pressure difference between the upstream side (inlet) and the downstream side (outlet) of the filter 33 is provided on the exhaust passage 31.

  On the other hand, as shown in FIG. 2, the vehicle is provided with a system management means (system management unit) 11 for comprehensively managing and controlling the hybrid system, and the differential pressure sensor 34 is provided with the system management means 11. Is connected to the forced regeneration means 35 provided in FIG. Here, the forced regeneration means 35 accumulates a predetermined amount of PM on the filter 33 when the differential pressure between the upstream side and the downstream side of the filter 33 exceeds a predetermined value based on the information from the differential pressure sensor 34. It is determined that the filter 33 is clogged, and forced regeneration of the filter 33 is executed.

  When forced regeneration is started by the forced regeneration means 35, a forced regeneration command is output to the injector 10, and additional fuel injection (post-injection) is executed after main fuel injection. This post-injection is, for example, injected in the exhaust stroke. By injecting fuel at such timing, the fuel reaches the oxidation catalyst 32 without burning in the cylinder, the exhaust passage, or the like, and the catalyst 32 is injected. Oxidation (combustion) takes place at. As a result, the filter 33 on the downstream side of the catalyst 32 is heated, the temperature of the filter 33 is increased to a temperature at which PM can be oxidized (600 ° C.), and PM incineration (filter regeneration) is performed. ing. Further, such a post fuel injection amount is set according to the engine speed Ne, the load (here, the main injection amount qmain), the outlet temperature of the catalyst 32, and the like.

  On the other hand, the system management means 11 includes an engine control unit (ECU) 12 that controls the engine output and a motor control unit (MCU) 13 that controls the motor output by controlling the operating state of the inverter 5. Although not shown, a transmission controller that sets the target gear position of the transmission 4 and controls the operation of the GSU 9 and a clutch controller that controls the connection / disconnection state of the clutch 3 in cooperation with the transmission controller are also provided. ing.

  Further, in the system management means 11, the required torque calculation means 14 for calculating the required torque for the drive source 8 based on the running state of the vehicle and the driving operation state of the driver, and the required torque calculation means 14 are used. Of the required torque of the drive source 8, output distribution determining means 15 is provided for setting the output torque (engine output distribution) handled by the engine 1 and the output torque (motor output distribution) handled by the motor 2.

In addition to the differential pressure sensor 34, the system management means 11 includes an engine speed sensor 21 for detecting the engine speed Ne of the engine 1 and an accelerator for detecting the accelerator depression amount (accelerator opening) θ _ACC of the driver. An opening sensor 23 and a remaining capacity sensor 24 for detecting the remaining capacity (SOC) of the battery 6 are connected.
Here, as shown in the figure, the engine speed Ne and the accelerator opening θ _ACC detected by the engine speed sensor 21 and the accelerator opening sensor 23 are input to the required torque calculation means 14. In the required torque calculation means 14, the driver calculates the required torque T for the drive source 8 composed of the engine 1 and the motor 2 based on the information (Ne, θ _ACC ).

  The output distribution determining means 15 is connected to a remaining capacity sensor 24 that calculates the remaining capacity SOC of the battery 6 based on the battery voltage and the battery current. Further, the output distribution determining means 15 uses the remaining battery capacity SOC obtained by the remaining capacity sensor 24 and the requested total torque T set by the requested torque calculating means 14 as parameters, and the output distribution between the engine 1 and the motor 2. An output distribution setting map is set for setting the output distribution (torque distribution or ratio) of the engine 1 and the motor 2 from this map.

  Here, the output distribution setting map will be described. The output distribution determining means 15 includes an output distribution setting map (first map) for normal control shown in FIG. 3 and an output distribution setting for forced regeneration shown in FIG. The map (second map) is provided, and the map to be applied is switched according to the driving state of the vehicle. Specifically, the second map is applied only when the vehicle is traveling and the filter 33 is forcibly regenerated, and the first map is applied in other cases.

  Among these, as shown in FIG. 3, the first map sets the output distribution between the engine 1 and the motor 2 to 100: 0 when the remaining capacity SOC of the battery 6 is not more than a first predetermined value V1 (for example, 20%). At the same time, the characteristic is set such that the output distribution is set to 0: 100 when the remaining capacity SOC becomes equal to or greater than a second predetermined value V2 (> first predetermined value V1, for example, 80%). Further, when the remaining capacity SOC is between the first predetermined value V1 and the second predetermined value V2, the output distribution is linearly changed between 100: 0 and 0: 100 according to the remaining capacity SOC. The characteristic is set.

That is, in this first map, basically, as the remaining capacity SOC decreases, the ratio of torque shared by the engine 1 increases (the ratio of torque shared by the motor 2 decreases). Conversely, the remaining capacity SOC decreases. As the torque increases, the ratio of torque shared by the engine 1 decreases (the ratio of torque shared by the motor 2 increases).
The first predetermined value V1 is an SOC lower limit value at which the motor 2 can output an effective torque. When the SOC is equal to or lower than the first predetermined value V1, the motor 2 is controlled in order to suppress a further decrease in the SOC. Is set to 0%, and the drive wheels 7 are driven only by the torque of the engine 1. Further, the second predetermined value V2 is an SOC that can determine that the battery 6 is fully charged. If the SOC is equal to or higher than the second predetermined value V2, the battery 6 is overcharged and the battery 6 deteriorates. In order to prevent this, the battery 6 is discharged by setting the output distribution of the motor 2 to 100%.

  Further, as shown in FIG. 4, the second map sets the output distribution between the engine 1 and the motor 2 to 100: 0 when the remaining capacity SOC of the battery 6 is not more than a third predetermined value V3 (for example, 65%). In addition, when the remaining capacity SOC becomes equal to or greater than a fourth predetermined value V4 (> third predetermined value V3, for example, 80%), the torque distribution is set to a characteristic that is set to 0: 100. Further, when the remaining capacity SOC is between the third predetermined value V3 and the fourth predetermined value V4, the torque distribution is linearly changed between 100: 0 and 0: 100 according to the remaining capacity SOC. The characteristic is set.

  Here, at least in the present embodiment, the third predetermined value V3> the first predetermined value V1 is set. Further, the fourth predetermined value V4 is set to the second predetermined value V2. That is, in the first map and the second map, the normal battery charge state (first predetermined value V1 to second) excluding the region of full charge SOC or more (V2, V4 or more) and the lower limit SOC or less (V1 or less). At the predetermined value V2), the output distribution characteristics of these two maps are set so that the output distribution of the engine 1 set in the second map is always larger than the output distribution set in the first map. Has been. Note that the relationship between the second predetermined value V2 and the fourth predetermined value V4 should be at least the fourth predetermined value V4 ≧ the second predetermined value V2.

  When the vehicle speed sensor (not shown) detects that the vehicle is running and the forced regeneration means 35 determines the forced regeneration start of the filter 33, the second map is used until the forced regeneration is completed. Output distribution between the engine 1 and the motor 2 is set. At other times, that is, other than forced regeneration, output distribution between the engine 1 and the motor 2 is set using the first map.

As a result, when the filter 33 is forcibly regenerated, the output distribution of the engine 1 is increased and the output distribution of the motor 2 is decreased, compared to a case other than the forced regeneration.
On the other hand, when the output distribution is determined in this way, the target torque Te of the engine 1 and the target of the motor 2 are calculated based on the required torque T of the drive source 8 calculated by the required torque calculation means 14 and the above output distribution. Torque Tm is set.

  In addition, when the engine target torque Te and the motor target torque Tm are set as described above, the engine target torque Te is input to the ECU 12, and the ECU 12 outputs the engine target torque Te. The injector drive time for this is set (or calculated). Thereby, the injector 10 is driven with the injector driving time set by the ECU 12, and the engine 1 is controlled so that the engine output torque becomes the target torque Te.

When the motor target torque Tm is set, the motor target torque Tm is input to the MCU 13 and the operation of the inverter 5 is controlled so as to be the target torque Tm. As a result, the motor 2 is controlled so that the motor output torque becomes the target torque Tm.
Incidentally, the switching from the first map to the second map at the time of forced regeneration of the filter 33 is mainly due to the following reason. That is, when the vehicle 2 is traveling mainly (when the output distribution of the motor 2> the output distribution of the engine 1), the fuel injection amount decreases because the engine 1 is in a low load operation or an idle operation. ing. If the forced regeneration of the filter 33 is executed in such a state, the main injection amount is originally small even if the post fuel injection is executed, so that a sufficient amount of heat is given to the filter 33 even if the post fuel injection amount is increased. I can't. For this reason, the forced regeneration time becomes longer, resulting in a deterioration in fuel consumption.

Therefore, in the present apparatus, when the filter 33 is forcibly regenerated, the first map for normal control is switched to the second map for forced regeneration, and the engine 1 with respect to the required torque of the drive source 8 calculated by the required torque calculation means 14 is switched. The output distribution of the motor 1 is increased and the output distribution of the motor 2 is decreased to increase the fuel injection amount of the engine 1.
In this case, although the output of the motor 2 is reduced, the output torque of the entire drive source is set to be equal to the required torque T, so that the filter can be quickly filtered without impairing drivability such as poor acceleration. 33 can be reproduced. Therefore, the fuel consumption can be improved.

  Further, when the vehicle is stopped, the first map for normal control is applied even if forced regeneration is started. This is because when the vehicle is stopped, even if the engine output distribution is set to 100% using the second map, the operating state of the engine 1 is only an idle operation and it is not possible to expect an increase in the fuel injection amount. It is. That is, in such an idle operation state, even if the first map is switched to the second map, the fuel injection amount cannot be increased, and the forced regeneration time of the filter cannot be shortened. Therefore, in this embodiment, when the vehicle is stopped, the output distribution is set using the first map for normal control even if the forced regeneration is started.

Since the hybrid vehicle motor control device according to the embodiment of the present invention is configured as described above, its operation will be described below with reference to the flowchart of FIG.
First, the required torque calculation means 14 takes in the engine speed Ne, the accelerator depression amount θ _ACC , and the remaining battery capacity SOC from the engine speed sensor 21 and the accelerator opening sensor 23 (step S1), and among these parameters, A required torque T for the drive source 8 is calculated from the engine speed Ne and the accelerator depression amount θ _ACC (step S2).

  Once the required torque T has been calculated, information from the forced regeneration means 35 is then taken to determine whether or not the filter 33 is undergoing forced regeneration (step S3). If it is during forced regeneration, it is determined whether or not the vehicle is traveling (step S4), and the second map for forced regeneration is selected only when it is determined that the vehicle is forcibly regenerating and traveling (step S5). If not, the first map for normal control is selected (step S6).

Then, an output distribution between the engine 1 and the motor 2 with respect to the required torque T is obtained from the selected map according to the battery remaining capacity SOC (step S7). Thereby, the target torque Te of the engine 1 is calculated, the target torque Tm of the motor 2 is calculated, and the injector 10 and the inverter 5 are controlled so as to be the target torque.
Here, since the second map is set to have a characteristic that the output distribution of the engine 1 is increased as compared with the first map, the output distribution of the engine 1 is increased at the time of forced regeneration during traveling of the vehicle. It will be. Accordingly, a shortage of fuel injection amount during forced regeneration can be avoided, and removal of PM accumulated in the filter is promoted. For this reason, there is an advantage that forced regeneration is completed early and fuel consumption is improved.

At this time, since the output distribution of the motor 1 is decreased, the drive source as a whole outputs a torque equivalent to the driver's required torque, so that the vehicle driving force is not affected. Therefore, drivability is not reduced.
Further, in the forced regeneration during traveling, the first map is selected when the forced regeneration is completed, so that the output distribution of the engine 1 is quickly reduced and the engine noise is reduced. At this time, since the torque distribution of the motor output is increased, the vehicle driving force is not affected.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, a first map for normal control and a second map for forced regeneration that is set so that the engine output distribution is larger than the first map are provided, and whether or not forced regeneration is performed Although these maps are switched in accordance with the above, various other methods can be applied to the method of increasing the engine output distribution during the forced regeneration. For example, a basic map for setting the output distribution between the engine and the motor may be provided, and at the time of forced regeneration, the engine output distribution may be increased by applying a predetermined coefficient to the output distribution set in this basic map. .

  Further, as shown in FIG. 6, the present invention may be applied to a hybrid vehicle in which an engine 1 and a motor 2 are provided adjacent to each other and a clutch 3 is interposed between the motor 1 and the transmission 4. .

1 is a schematic diagram showing a power train of a vehicle to which a hybrid vehicle motor control device according to an embodiment of the present invention is applied. It is a block diagram which paid its attention to the principal function of the motor control apparatus of the hybrid vehicle which concerns on one Embodiment of this invention. It is a map which shows the output distribution characteristic at the time of the normal control of the motor control apparatus of the hybrid vehicle which concerns on one Embodiment of this invention. It is a map which shows the output distribution characteristic at the time of forced regeneration of the motor control apparatus of the hybrid vehicle which concerns on one Embodiment of this invention. It is a flowchart for demonstrating the effect | action of the motor control apparatus of the hybrid vehicle which concerns on one Embodiment of this invention. It is a figure shown about the modification of the motor control apparatus of the hybrid vehicle which concerns on one Embodiment of this invention.

Explanation of symbols

1 Engine 2 Electric motor (motor)
3 Clutch 4 Transmission 5 Inverter 6 Battery 7 Drive Wheel 8 Drive Source 9 Gear Shift Unit (GSU)
10 injector 11 system management means 12 engine control unit (ECU)
13 Motor control unit (MCU)
14 required torque calculation means 15 output distribution determination means 21 engine speed sensor 22 input shaft speed sensor 23 accelerator opening sensor 24 residual capacity sensor 31 exhaust passage 32 oxidation catalyst 33 filter 34 differential pressure sensor 35 forced regeneration means

Claims (3)

A diesel engine installed in the vehicle,
A motor mounted on the vehicle;
A battery connected to the motor in a chargeable / dischargeable manner;
Output distribution determining means for respectively determining output distribution of the diesel engine and the motor for the required driving force based on the driving force required for traveling of the vehicle and the state of charge of the battery;
A filter for collecting particulate matter in the exhaust gas of the diesel engine;
Forcibly regenerating the filter, and
The output distribution determining means increases the output distribution of the diesel engine with respect to the required driving force when the vehicle is running and the forced regeneration by the forced regeneration means is being executed. A motor control device for a hybrid vehicle, wherein the motor output distribution with respect to the force is reduced. The output distribution determination means reduces the output distribution of the diesel engine with respect to the driving force when the vehicle is running and the execution of the forced regeneration is completed, and the motor distribution with respect to the propulsive force. The motor control device for a hybrid vehicle according to claim 1, wherein output distribution is increased. The hybrid vehicle motor control device according to claim 1, wherein an output shaft of the diesel engine is connected to an input shaft of the motor via a clutch.

Images