JP5584282B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid vehicle, and more particularly, a technique for reducing harmful exhaust gas components during catalyst warm-up and improving fuel consumption after completion of catalyst warm-up without changing driving feeling or the like. About.

  Many 4-cycle gasoline engines (hereinafter simply referred to as engines) are equipped with various variable valve gears in order to improve output and fuel consumption, reduce harmful exhaust gas components, and the like. As a variable valve operating device, a low-speed cam and a high-speed cam are generally used to change the cam phase and the valve lift at the same time, but the cam phase variable mechanism and the variable valve lift mechanism are used to change the cam phase. There are also those that individually variably control the phase and the valve lift (see Patent Document 1).

  In an engine equipped with a variable valve device, a valve opening mode (hereinafter referred to as EM valve opening mode) suitable for raising the temperature of the catalyst until the exhaust gas purification catalyst (hereinafter simply referred to as catalyst) reaches an activation temperature after starting. May be operated in a valve opening mode (hereinafter referred to as a fuel consumption opening mode) that suppresses fuel consumption after the warm-up of the catalyst is completed. For example, in an HCCI engine that switches between premixed compression ignition (hereinafter referred to as HCCI) and spark ignition (hereinafter referred to as SI) according to the operating state, HCCI (fuel consumption valve opening mode) TSI (transitional spark ignition) for spark ignition with an excess air ratio λ of 1.0 is set between A and SI, and TSI is originally set as a warm-up mode during cold start or catalyst warm-up. One that is applied to a part of the region operated by HCCI has been proposed (see Patent Document 2).

  On the other hand, a hybrid vehicle has appeared in which an internal combustion engine and an electric motor are provided side by side, and at least one of the internal combustion engine and the electric motor is used as a driving power source in accordance with the traveling state of the automobile and the will of the driver ( (See Patent Document 3). Hybrid vehicles use an internal combustion engine and an electric motor at the same time to obtain high acceleration performance and climbing ability, and use only an electric motor to reduce fuel consumption and quietness during night driving. There are various features such as the ability to recover travel energy as electric energy by using a motor as a generator.

JP 2008-163768 A Japanese Patent No. 3936901 JP 2009-292287 A

  In the engine disclosed in Patent Document 2 described above, when the operation of the internal combustion engine shifts from TSI to HCCI when the warm-up of the catalyst is completed, the generated torque of the internal combustion engine changes suddenly even though the amount of accelerator pedal depression is the same. There was something to do. As a result, there is a problem that the driver feels uncomfortable with the driving feeling and the drivability is lowered. Moreover, since the operation by TSI is performed in a part of the region that is originally HCCI, there is a problem that it is difficult to obtain the effect of reducing harmful exhaust gas components by HCCI.

  The present invention has been made in view of such a background, and provides a control device for a hybrid vehicle that realizes reduction of harmful exhaust gas components during catalyst warm-up operation without any change in driving feeling or the like. Objective.

The present invention includes an internal combustion engine (2) as a first travel drive source, a motor generator (3) as a second travel drive source that also functions as a regenerative brake, and an intake valve (22) of the internal combustion engine. ) And the exhaust valve (23), the valve opening characteristic variable device (26, 27) for variably controlling the valve opening characteristic, the exhaust purification device (16) for purifying the exhaust gas of the internal combustion engine, and the motor A hybrid vehicle control device (41) having a battery (33) for transmitting and receiving electric power to and from a generator, and a requested engine output detection device (42) for detecting a requested engine output of a driver, the engine rotation the speed and engine torque as parameters, said driving said valve opening characteristic changing device so as to increase the intake air amount so as to suppress the harmful exhaust gas components in the exhaust gas EM Hirakibenmo A region for executing de, said the region for executing the fuel valve opening mode to drive the valve opening characteristic changing device so as to decrease the intake air amount to suppress the fuel consumption of the internal combustion engine, the fuel consumption rate is lowest becomes the target operating line has is set mode map, the exhaust until the warm-up completion of the purifying apparatus, wherein the fuel valve opening mode and a target operating line of the mode map and the required engine output The valve opening characteristic variable device is driven and controlled by the EM valve opening mode in at least a part of the EM valve opening mode, and there is a difference between the generated output of the internal combustion engine and the required engine output by executing the EM valve opening mode. When it occurs, the motor generator is operated to compensate for the output difference. Further, in the above invention, the internal combustion engine includes two intake valves per cylinder, and the valve opening characteristic variable device closes one of the intake valves of each cylinder in a region where the fuel consumption valve opening mode is executed. Good.

In the above invention , the engine speed and the engine torque are set on the target operation line until the exhaust purification device is warmed up, and the engine speed is set to the fuel consumption valve opening mode. it may prohibit to migrate to the region of the run.

In the above invention , the valve opening characteristic variable device is driven and controlled by the EM valve opening mode in at least a part of the fuel economy valve opening mode until the exhaust purification device is warmed up. In this case , it is preferable not to change the engine speed set by the required engine output and the target operation line.

Further, in the above invention, after completion of the warm-up of the exhaust emission control device, the valve opening characteristic in at least some cases from said target operating line of the mode map and the required engine output becomes the EM valve opening mode The variable device is driven and controlled in the fuel consumption valve opening mode, and the output difference is compensated when a difference occurs between the generated output of the internal combustion engine and the required engine output by executing the fuel consumption valve opening mode. The motor generator may be operated as described above.

  According to the present invention, the exhaust emission control device is easily operated in the EM valve opening mode until the warm-up of the exhaust gas purification apparatus is completed, and harmful exhaust gas components from the internal combustion engine are reduced, while the internal combustion engine by executing the EM valve opening mode is reduced. The decrease in engine output and the increase in output are compensated by the motor generator, making it difficult for the driver to feel uncomfortable with the driving feeling. In addition, if the internal combustion engine is easily operated in the fuel consumption valve opening mode after the warm-up is completed, the fuel consumption can be improved, while the output increase / decrease of the internal combustion engine by executing the fuel consumption valve opening mode causes the motor generator to It is compensated by operating as a regenerative brake, and it becomes difficult for the driver to feel uncomfortable in driving feeling.

It is a schematic diagram which shows the power unit which concerns on embodiment. It is a flowchart which shows the procedure of the output control which concerns on 1st Embodiment. It is an engine speed-engine torque map concerning an embodiment. It is a valve opening mode map concerning an embodiment. It is operation | movement explanatory drawing of 1st Embodiment. It is a flowchart which shows the procedure of the output control which concerns on 2nd Embodiment. It is a valve opening mode map at the time of warming-up which concerns on embodiment. It is a flowchart which shows the procedure of the output control which concerns on 3rd Embodiment. It is operation | movement explanatory drawing of 3rd Embodiment.

  Hereinafter, some embodiments in which the present invention is applied to power unit control of an automobile (hybrid vehicle) will be described in detail with reference to the drawings.

[First Embodiment]
<< Configuration of First Embodiment >>
As shown in FIG. 1, the power unit 1 according to this embodiment includes an engine 2 and a motor generator 3, and applies driving force to left and right front wheels (not shown) via a transmission 4 integrated with a differential device.

  The engine 2 is an inline 4-cylinder HCCI engine, and includes an intake system including an air cleaner 11, an electric throttle valve 12, a surge tank 13, an intake pipe 14, and the like, an exhaust manifold 15, an exhaust purification catalyst 16, an exhaust pipe 17, and the like. It has an exhaust system. The cylinder head 21 of the engine 2 includes a pair of intake valves 22, a pair of exhaust valves 23, a fuel injection valve 24 for in-cylinder injection, a spark plug 25, and intake and exhaust valves 22, 23 for each cylinder. Are provided with variable valve mechanisms 26, 27, etc. The intake pipe 14 is provided with an intake pipe injection fuel injection valve 28 for each cylinder. The variable valve mechanisms 26 and 27 of the present embodiment include three types of cams having different cam phases and lift amounts so that the valve opening characteristics of the intake and exhaust valves 22 and 23 can be switched in three stages.

  The motor generator 3 includes a motor 31 that is used for driving force assist for the engine 2 and electric running, and a generator 32 that converts the output of the engine 2 and the running energy of the automobile into electric power. A transmission and a differential device (not shown) are provided. Via the left and right front wheels. The motor generator 3 is connected to a battery 33 mounted at the rear of the vehicle body of the automobile, and exchanges power with the battery 33. A downverter 34 composed of a DC-DC converter or the like is connected to the battery 33, and the electric power that has been stepped down to 12V by the downverter 34 is used in various electric auxiliary machines (such as an electric air conditioner and an electric water pump) and an electric device. (Lights, electric heaters, etc.)

  A PCU (power control unit) 41 is mounted on the body of the automobile, and the PCU 41 controls the engine 2 and the motor generator 3 in an integrated manner. In addition to information from the engine 2, the motor generator 3, the battery 33, and the like, the PCU 41 receives information on the amount of depression of the accelerator pedal 43 from the accelerator sensor 42 (that is, the driver's requested engine output).

<< Operation of First Embodiment >>
When driving of the automobile is started, the PCU 41 repeatedly executes output control whose procedure is shown in the flowchart of FIG. 2 at a predetermined control interval (for example, 10 msec).
When the output control is started, the PCU 41 determines in step S1 whether or not the exhaust purification catalyst 16 is warming up based on a detection signal of an exhaust temperature sensor (not shown). If this determination is No, step S2 is performed. The target engine output PEtgt of the engine 2 is calculated by the following equation (1). In the following equation, PEdd is the driver's requested engine output obtained based on the detection signal of the accelerator sensor 42, and Pdv is the power consumption of the downverter 34.
PEtgt = PEdd + Pdv (1)

  Next, in step S3, the PCU 41 sets the current target engine output PEtgt to the EM valve opening mode on the target operation line (the line where the fuel consumption / generated output of the engine 2 becomes the smallest) in the valve opening mode map of FIG. VM1 (a valve opening mode for increasing the intake air amount to raise the temperature of the exhaust purification catalyst 16) and a fuel consumption valve opening mode VM2 (for example, to improve fuel efficiency, one of the intake valves 22 is closed and swirl is performed. (In FIG. 4, it exists in the fuel efficiency valve opening mode VM2).

  Next, in step S4, the PCU 41 sets the target engine speed NEtgt and the target engine torque TEtgt from the target engine output PEtgt and the target operation line based on the engine speed-engine torque map of FIG. Thereafter, in step S5, the PCU 41 drives and controls the engine 2 (that is, the fuel injection valves 24 and 28, the spark plug 25, the variable valve mechanisms 26 and 27, etc.) based on the processing results of steps S3 and S4.

  On the other hand, if the determination in step S1 is Yes, such as immediately after the engine 2 is started, the PCU 41 calculates the target engine output PEtgt of the engine 2 by the above-described equation (1) in step S6. Next, in step S7, the PCU 41 determines whether the target engine output PEtgt is present in the EM valve opening mode VM1 from the current target engine speed NEtgt and the target engine torque TEtgt based on the valve opening mode map of FIG. Determine whether. And if this determination is Yes, PCU41 will transfer to step S4, S5, and will drive-control the engine 2 by EM valve opening mode VM1.

  If the target engine output PEtgt exists in the fuel efficiency valve opening mode VM2 and the determination in step S7 is No, the PCU 41 shifts to the EM valve opening mode VM1 in step S8 as indicated by an arrow in FIG. Therefore, after calculating the corrected engine output PE ′ obtained by reducing the target engine output PEtgt along the target operation line, the corrected target engine speed NEtgt ′ and the corrected target engine torque TEtgt ′ are set in step S9. Next, in step S10, the PCU 41 drives and controls the fuel injection valves 24 and 28, the spark plug 25, and the like based on the processing result of step S9, and drives and controls the variable valve mechanisms 26 and 27 in the EM valve opening mode VM1. To do.

  Next, in step S12, the PCU 41 determines that the target engine output PEtgt (that is, the product of the target engine speed NEtgt and the target engine torque TEtgt) and the corrected engine output PE ′ (that is, the corrected target engine speed NEtgt ′ and the corrected target engine). After calculating the difference from the product of the torque TEtgt 'as an output fluctuation amount ΔP (output shortage), in step S13, the motor generator 3 (motor 31) is assisted with driving force so as to compensate for the output fluctuation amount ΔP. .

[Second Embodiment]
The second embodiment includes the same power unit as that of the first embodiment described above, but the procedure of output control is different, so only the operation thereof will be described.

<< Operation of Second Embodiment >>
When the driving of the automobile is started, the PCU 41 repeatedly executes output control whose procedure is shown in the flowchart of FIG. 6 at a predetermined control interval (for example, 10 msec).
When the output control is started, the PCU 41 determines in step S21 whether or not the exhaust purification catalyst 16 is warming up based on a detection signal of an exhaust temperature sensor (not shown). If this determination is No, step S22 is performed. Then, the target engine output PEtgt of the engine 2 is calculated by the above-described equation (1).

  Next, in step S23, the PCU 41 determines whether the current target engine output PEtgt exists in the EM valve opening mode VM1 or the fuel efficiency valve opening mode VM2 based on the valve opening mode map of FIG. .

  Next, in step S24, the PCU 41 sets the target engine speed NEtgt and the target engine torque TEtgt from the target engine output PEtgt and the target operation line based on the engine speed-engine torque map of FIG. 4 described above. Thereafter, in step S25, the PCU 41 drives and controls the engine 2 (that is, the fuel injection valves 24 and 28, the spark plug 25, the variable valve mechanisms 26 and 27, etc.) based on the processing results of steps S23 and S24.

  On the other hand, if the determination in step S21 is Yes, such as immediately after the engine 2 is started, the PCU 41 calculates the target engine output PEtgt of the engine 2 by the above-described equation (1) in step S26. Next, in step S27, the PCU 41 determines whether or not the target engine output PEtgt exists in the EM valve opening mode VM1 based on the warm-up valve opening mode map of FIG. For example, the process goes to steps S24 and S25 to drive and control the engine 2 in the fuel consumption valve opening mode VM2.

  If the target engine output PEtgt is present in the EM valve opening mode VM1 and the determination in step S27 is Yes, the PCU 41 in step S28 in the EM valve opening mode VM1 without changing the engine operating point (engine speed NE). After calculating the engine output when the engine 2 is operated as the corrected engine output PE ′, the corrected target engine torque TEtgt ′ is set in step S29. Next, in step S30, the PCU 41 drives and controls the fuel injection valves 24 and 28, the spark plug 25, and the like based on the processing result in step S29, and drives and controls the variable valve mechanisms 26 and 27 in the EM valve opening mode VM1. To do.

  Next, in step S31, the PCU 41 calculates the product of the target engine speed NEtgt and the target engine torque TEtgt) and the corrected engine output PE ′ (that is, the product of the target engine speed NEtgt and the corrected target engine torque TEtgt ′). After the difference is calculated as the output fluctuation amount ΔP, the motor generator 3 (generator 32) charges and discharges the battery 33 in step S32 to cancel the output fluctuation amount ΔP.

[Third Embodiment]
Although the third embodiment also includes the same power unit as that of the first embodiment described above, the procedure of output control is different, so only the operation thereof will be described.
<< Operation of Third Embodiment >>
When the driving of the automobile is started, the PCU 41 repeatedly executes output control whose procedure is shown in the flowchart of FIG. 8 at a predetermined control interval (for example, 10 msec).
When the output control is started, the PCU 41 determines in step S41 whether or not the exhaust purification catalyst 16 is warming up based on a detection signal of an exhaust temperature sensor (not shown). If this determination is Yes, step S42 is performed. Then, the target engine output PEtgt of the engine 2 is calculated by the above-described equation (1).

  Next, in step S43, the PCU 41 determines whether or not the current target engine output PEtgt exists in the EM valve opening mode VM1 based on the valve opening mode map of FIG. 3 described above. If this determination is Yes, in step S44, the PCU 41 determines the target engine speed NEtgt and the target engine from the target engine output PEtgt and the target operation line based on the engine speed-engine torque map of FIG. Torque TEtgt is set. Thereafter, in step S45, the PCU 41 drives and controls the engine 2 in the EM valve opening mode VM1 based on the processing result in step S44.

  If the target engine output PEtgt exists in the fuel efficiency valve opening mode VM2 and the determination in step S43 is No, the PCU 41 switches to the EM valve opening mode VM1 in step S46 as indicated by an arrow in FIG. In order to shift, after calculating the corrected engine output PE ′ obtained by reducing the target engine output PEtgt along the target operation line, the corrected target engine rotational speed NEtgt ′ and the corrected target engine torque TEtgt ′ are set in step S47. Next, in step S48, the PCU 41 controls the drive of the engine 2 in the EM valve opening mode VM1 based on the processing result of step S47.

  Next, in step S49, the PCU 41 calculates the product of the target engine speed NEtgt and the target engine torque TEtgt) and the corrected engine output PE ′ (that is, the product of the corrected target engine speed NEtgt ′ and the corrected target engine torque TEtgt ′). Is calculated as an output fluctuation amount ΔP, and then the battery generator 33 is charged / discharged from the motor generator 3 (generator 32) in step S50 to cancel the output fluctuation amount ΔP.

  On the other hand, when the warm-up of the exhaust purification catalyst 16 is completed and the determination in step S41 is No, the PCU 41 calculates the target engine output PEtgt of the engine 2 by the equation (1) in step S51. Next, in step S52, the PCU 41 determines whether or not the target engine output PEtgt is present in the fuel efficiency valve opening mode VM2 from the current target engine speed NEtgt and the target engine torque TEtgt based on the valve opening mode map of FIG. Determine whether. If this determination is Yes, in step S53, the PCU 41, based on the engine speed-engine torque map of FIG. 4, calculates the target engine speed NEtgt and the target engine torque TEtgt from the target engine output PEtgt and the target operation line. And set. Thereafter, in step S54, the PCU 41 controls the drive of the engine 2 in the fuel consumption valve opening mode VM2 based on the processing result of step S53.

  If the target engine output PEtgt exists in the EM valve opening mode VM1 and the determination in step S52 is No, the PCU 41 enters the fuel consumption valve opening mode VM2 in step S55 as indicated by an arrow in FIG. In order to shift, the corrected engine output PE ′ obtained by increasing or decreasing the target engine output PEtgt along the target operation line is calculated, and then the corrected target engine rotational speed NEtgt ′ and the corrected target engine torque TEtgt ′ are set in step S56. Next, in step S57, the PCU 41 controls the drive of the engine 2 in the fuel consumption opening mode VM2 based on the processing result of step S56.

  Next, in step S58, the PCU 41 calculates the product of the target engine speed NEtgt and the target engine torque TEtgt) and the corrected engine output PE ′ (that is, the product of the corrected target engine speed NEtgt ′ and the corrected target engine torque TEtgt ′). Is calculated as the output fluctuation amount ΔP, and then the battery generator 33 is charged / discharged from the motor generator 3 (generator 32) in step S59 to cancel the output fluctuation amount ΔP.

  In each embodiment, by adopting the above-described configuration, when the exhaust purification catalyst 16 is warmed up, the engine 2 is operated in the EM valve opening mode VM1 to reduce harmful exhaust gas components and output fluctuations. Since ΔP is compensated by the driving force assist of the motor generator 3 and charging / discharging of the battery 33, it is possible to effectively suppress the driver from feeling uncomfortable in driving feeling and the decrease in drivability.

  Although the description of the specific embodiments is finished as described above, the present invention is not limited to these embodiments and can be widely modified. For example, if there is a margin in the battery 33 in the second and third embodiments, the driving force assist can be performed by the motor 31 as in the first embodiment. In addition, the specific configuration of the power unit, the specific procedure of the control, and the like can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Power unit 2 Engine 3 Motor generator 16 Exhaust purification catalyst 22 Intake valve 23 Exhaust valve 26, 27 Variable valve mechanism (Valve opening characteristic variable device)
31 Motor 32 Generator 33 Battery 34 Downverter 41 PCU (Control Device)
42 Accelerator sensor (required engine output detection device)

Claims (5)

An opening characteristic of at least one of an internal combustion engine as a first travel drive source, a motor generator as a second travel drive source that also functions as a regenerative brake, and an intake valve and an exhaust valve of the internal combustion engine A variable valve opening characteristic control device that variably controls, an exhaust purification device that purifies exhaust gas of the internal combustion engine, a battery that transfers power to and from the motor generator, and a request engine that detects a driver's request engine output A hybrid vehicle control device having an output detection device,
A region for executing the EM valve opening mode for driving the valve opening characteristic variable device so as to increase the intake air amount so as to suppress harmful exhaust gas components in the exhaust gas using the engine rotation speed and the engine torque as parameters, A region for executing the fuel consumption valve opening mode for driving the variable valve opening characteristic device so as to reduce the intake air amount so as to suppress the fuel consumption amount of the internal combustion engine, and a target operation line where the fuel consumption rate becomes the lowest are set. Mode map
Wherein until the warm-up of the exhaust purification device is completed, the open by the EM valve opening mode in at least some cases from said target operating line of the mode map and the required engine output becomes the fuel valve opening mode Drive and control the valve characteristic variable device,
When the EM valve opening mode is executed, if a difference occurs between the generated output of the internal combustion engine and the required engine output, the motor generator is operated to compensate for the output difference. Car control device. The internal combustion engine comprises two intake valves per cylinder;
2. The hybrid vehicle control device according to claim 1, wherein the valve opening characteristic variable device closes one of the intake valves of each cylinder in a region in which the fuel efficiency valve opening mode is executed . The engine speed and the engine torque are set on the target operation line until the exhaust purification device is warmed up, and the engine speed is shifted to a region where the fuel consumption valve opening mode is executed. The hybrid vehicle control device according to claim 1, wherein the control device is prohibited.   When the valve opening characteristic variable device is driven and controlled by the EM valve opening mode in at least a part of the fuel economy valve opening mode until the exhaust gas purification device is warmed up, the required engine output and 3. The hybrid vehicle control device according to claim 1, wherein the engine speed set by the target operation line is not changed. Wherein after completion of the warm-up of the exhaust purification device, the request at least a portion in the valve opening characteristics variable apparatus the fuel valve opening when the engine output from said mode map the target operating line becomes the EM valve opening mode The motor generator is operated so as to compensate for the output difference when a difference occurs between the generated output of the internal combustion engine and the required engine output by executing the fuel consumption valve opening mode. The hybrid vehicle control device according to claim 1, wherein the control device is a hybrid vehicle control device.

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