JP4193789B2 - Control method for starting internal combustion engine of hybrid vehicle - Google Patents

Description

  The present invention relates to a control method at the time of starting an internal combustion engine provided with a variable vibration isolation bearing device.

Some vehicles such as automobiles equipped with an internal combustion engine include a variable vibration isolation support device in order to prevent vibrations during idling of the internal combustion engine from being transmitted to the vehicle body side (for example, Patent Document 1). reference). According to this variable vibration isolating support device, it is possible to obtain a vibration isolating effect corresponding to the vibration during idling, so that drivability can be improved.
JP-A-11-82122

  However, Patent Document 1 only refers to suppressing vibration during idling, and does not refer to suppressing vibration during startup of the internal combustion engine. In particular, in a vehicle in which the start and stop of the internal combustion engine are frequently repeated, such as a hybrid vehicle that obtains driving force by the cooperation of the motor and the internal combustion engine, at the time of starting the internal combustion engine (under a condition where the engine speed is low). It is desirable to reduce vibration.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a technique for reducing vibration of a hybrid vehicle at the time of starting an internal combustion engine.

  In order to achieve the above object, an internal combustion engine start-up control method for a hybrid vehicle according to the present invention includes an internal combustion engine having a variable vibration isolation bearing device and a motor, and the internal combustion engine and the motor In a control method for starting an internal combustion engine of a hybrid vehicle that drives driving wheels using at least one of them as a driving source, from the start of the internal combustion engine to the start of transmission of power generated by the internal combustion engine to the driving wheels The damping of the variable vibration isolating bearing device is larger than after the start of transmission.

  In a hybrid vehicle that drives a drive wheel using at least one of an internal combustion engine and a motor provided with a variable vibration isolation bearing device as a drive source, start and stop of the internal combustion engine are frequently repeated. Until the start of transmission of the power generated by the internal combustion engine to the drive wheels, the damping of the variable vibration isolation bearing device is made larger than after the start of transmission of the power generated by the internal combustion engine to the drive wheels (during normal operation). By absorbing the vibration of the internal combustion engine when starting the internal combustion engine, the vibration of the hybrid vehicle when starting the internal combustion engine can be reduced. Further, when the power generated by the internal combustion engine is started to be transmitted to the drive wheels, the control is performed so that the attenuation of the variable vibration isolating support device is smaller than before the transmission is started. Can be transmitted to the drive wheel.

In other words, at the start of the internal combustion engine, the damping of the variable vibration isolating support device is made larger than normal, and the power generated by the internal combustion engine is applied to the drive wheels when the damping is changed to normal damping. This is based on the time when transmission is started. By doing so, the vibration of the hybrid vehicle at the start of the internal combustion engine is reduced, and the power generated by the internal combustion engine is transmitted to the drive wheels. Can be quickly transmitted to the drive wheels. Note that the normal time refers to a time when driving wheels are driven using an internal combustion engine and a motor as driving sources. Further, the time when the power generated by the internal combustion engine is started to be transmitted to the drive wheels can be exemplified as the time when a predetermined period has elapsed since the start of the internal combustion engine.

  In the control method for starting the internal combustion engine of the hybrid vehicle according to the present invention, the control method includes an internal combustion engine having a variable vibration isolation support device and a motor, and at least one of the internal combustion engine and the motor is provided. In the internal combustion engine start-up control method for a hybrid vehicle that drives a drive wheel as a drive source, the time from the start of the start of the internal combustion engine until the rotational speed of the internal combustion engine exceeds a predetermined rotational speed is greater than after the predetermined rotational speed is exceeded. The variable vibration-proof bearing device has a large attenuation.

  When the rotational speed of the internal combustion engine rises to some extent, even if the vibration of the internal combustion engine is transmitted to the vehicle body with the attenuation of the variable vibration isolation bearing device being reduced, the vibration is not unpleasant for the user of the hybrid vehicle. Therefore, from the start of the internal combustion engine until the rotational speed of the internal combustion engine exceeds the predetermined rotational speed, the damping of the variable vibration isolating support device is made larger than after the predetermined rotational speed is exceeded. By increasing the damping of the variable vibration isolating support device at the time of starting from the normal time and changing the damping to the damping at the normal time based on the time when the rotational speed of the internal combustion engine exceeds the predetermined rotational speed, The vibration of the hybrid vehicle at the start of the internal combustion engine can be reduced.

  Note that the predetermined rotational speed is a rotational speed that does not give unpleasant vibration to the user of the hybrid vehicle even if the vibration of the internal combustion engine is transmitted to the vehicle body side with the attenuation of the variable vibration isolation bearing device being reduced. The minimum value can be exemplified.

  The control method for starting an internal combustion engine of a hybrid vehicle according to the present invention includes an internal combustion engine having a variable vibration isolation support device, a motor, and engine vibration detection means for detecting vibration of the internal combustion engine. In the internal combustion engine start-up control method for a hybrid vehicle in which drive wheels are driven using at least one of the internal combustion engine and the motor as a drive source, the engine vibration detection means detects the start of the internal combustion engine from the start of the start. Until the vibration of the internal combustion engine becomes smaller than a predetermined value or the rotational speed of the internal combustion engine exceeds the predetermined rotational speed, the variable vibration-proof bearing device is more It is characterized by increasing attenuation.

  Since there are variations in the internal combustion engine, even if the rotational speed of the internal combustion engine does not exceed the predetermined rotational speed that is determined in advance, the actual vibration of the internal combustion engine is Even if it is transmitted to the vehicle body side in a state where the attenuation is reduced, the vibration value may be smaller than a vibration value that the user of the hybrid vehicle does not feel uncomfortable. Therefore, the engine vibration detecting means for detecting the vibration of the internal combustion engine is provided to actually detect the vibration of the internal combustion engine, and even if the rotational speed of the internal combustion engine exceeds the predetermined rotational speed, When the vibration becomes smaller than the vibration value (predetermined value), the attenuation of the variable vibration isolation bearing device that has been increased at the start of the start may be changed to the normal attenuation. As a result, the attenuation of the variable vibration isolating support device is changed to the normal attenuation earlier than waiting until the rotation speed of the internal combustion engine reaches the predetermined rotation speed. As a result, in a vehicle set to transmit the power generated by the internal combustion engine to the drive wheels after the attenuation of the variable vibration isolation bearing device is changed to be smaller than the magnitude at the time of starting, the predetermined rotational speed is obtained. Since the power of the internal combustion engine is started to be transmitted to the drive wheels at an earlier stage than when waiting for the acceleration, the acceleration performance can be improved.

However, the engine vibration detecting means for detecting the vibration of the internal combustion engine may be subject to disturbances other than vibration due to the combustion of the air-fuel mixture, such as when the hybrid vehicle travels on a rough road. Even when the engine speed reaches the predetermined rotational speed, the vibration of the internal combustion engine detected by the engine vibration detecting means does not become smaller than the predetermined value. Therefore, from the start of the internal combustion engine, either the state where the vibration of the internal combustion engine detected by the engine vibration detecting means becomes smaller than a predetermined value or the state where the rotational speed of the internal combustion engine exceeds the predetermined rotational speed is entered. Until then, it is preferable to increase the damping of the variable vibration isolation bearing device more than after the state is reached.

  Further, when the vibration of the internal combustion engine detected by the engine vibration detection means before the rotational speed of the internal combustion engine exceeds the predetermined rotational speed becomes smaller than the predetermined value, the rotational speed becomes smaller than the predetermined value. It is preferable that the rotational speed of the internal combustion engine at the time point is set as the predetermined rotational speed at the start of the internal combustion engine after the next time.

  This makes it difficult for the engine vibration detection means to accurately detect the value resulting from the combustion of the air-fuel mixture in the internal combustion engine, such as when the hybrid vehicle travels on a rough road when the internal combustion engine is started next time. Even under circumstances, when the engine speed becomes higher than the newly set predetermined speed, the variable vibration-proof bearing device is changed so that the attenuation is reduced. Therefore, in a vehicle set to transmit the power generated by the internal combustion engine to the drive wheels after the damping of the variable vibration isolation bearing device is changed so as to be smaller than the magnitude at the time of starting, the predetermined rotation Since the torque of the internal combustion engine is started to be transmitted to the drive wheels at an earlier stage than when the initial value is kept without resetting the number, the acceleration performance can be improved.

  In the above-described control method for starting an internal combustion engine of a hybrid vehicle according to the present invention, the predetermined rotational speed is corrected according to the temperature of cooling water and / or oil of the internal combustion engine. Since the vibration of the internal combustion engine depends on the temperature of the cooling water or the oil, variation in vibration due to the warm-up condition of the internal combustion engine can be suppressed by doing so.

  As described above, according to the present invention, it is possible to reduce the vibration of the hybrid vehicle when the internal combustion engine is started.

  The best mode for carrying out the present invention will be exemplarily described in detail below based on the following embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle 100 equipped with a hybrid system 1 according to the present embodiment. As shown in FIG. 1, the hybrid system 1 includes an internal combustion engine 2, a motor 3, a generator 4, a power split mechanism 5, a speed reducer 6, an inverter 7, a battery 8, an electronic control unit (ECU) 9, and the like as main components. Include as.

  The internal combustion engine 2 applies a rotational force to the drive wheels 10 and 11 of the vehicle and drives the generator 4 to generate electric power. The motor 3 receives power supplied from the battery 8 or the generator 4 and functions to apply rotational force to the drive wheels 10 and 11, and conversely applies rotational force from the drive wheels 10 and 11 and the internal combustion engine 2. As a result, the battery 8 may function to generate power and supply power for charging to the battery 8.

The crankshaft 21 of the internal combustion engine 2, the rotating shaft 3 a of the motor 3, and the rotating shaft 4 a of the generator 4 are connected to each other via the power split mechanism 5. The power split mechanism 5 uses a known planetary gear (not shown) to transmit the power generated by the internal combustion engine 2 (rotational force of the crankshaft 21) to the rotary shaft 3a of the motor 3 and the rotary shaft 4a of the generator 4. Divide and transmit. The rotating shaft 3a of the motor 3 and the crankshaft 21 can be appropriately connected or disconnected. Thereby, even when the internal combustion engine 2 stops engine combustion, the crankshaft 21 can be rotated using the power generated by the motor 3.

  The rotation shaft 3 a of the motor 3 is connected to the rotation shafts 10 a and 11 a of the drive wheels 10 and 11 via the speed reducer 6.

  Although details of the ECU 9 will be described later, the ECU 9 inputs detection signals of various sensors via an external input circuit, and based on these signals, grasps the operating states of the internal combustion engine 2, the motor 3, the battery 8, and the like. Then, various controls for optimizing the operating state of the hybrid system 1 are performed based on the operating states of these elements 2, 3, 8 and the like.

  The hybrid system 1 appropriately uses the power (shaft torque) generated by the internal combustion engine 2 and the motor 3 and transmits it to the drive wheels 10 and 11 of the vehicle, as well as appropriately driving force of the internal combustion engine 2 and deceleration of the vehicle. The battery 8 is charged by converting the energy generated along with this to electric power.

Hereinafter, the operation of the hybrid system 1 will be described with specific examples.
FIG. 2 shows how the power generated by the internal combustion engine 2 and the motor 3 and the power stored in the battery 8 are utilized according to the operating conditions of the hybrid system 1, focusing on the power and power transmission path. It is a schematic diagram demonstrated to. In each of FIGS. 2 (a), 2 (b), and 2 (c), a solid arrow indicates a power transmission path, and a broken arrow indicates a power transmission path.

(1) At system startup When the hybrid system 1 is started, the internal combustion engine 2 is started to warm up. At this time, a part of the energy generated by the internal combustion engine 2 is converted into electric power through the generator 4 and stored in the battery 8 (FIG. 2A). When the temperature of the cooling water of the internal combustion engine 2 exceeds a predetermined value (when the warm-up is completed), the operation of the internal combustion engine 2 is stopped. The internal combustion engine 2 is started when the generator 4 cranks the internal combustion engine 2 using the power of the battery 8.

(2) Start / light load driving When the hybrid vehicle 100 starts or runs at a low speed, the power generated by the motor 3 is preferentially used under conditions where the thermal efficiency of the internal combustion engine 2 is low. Then, the vehicle (drive wheels 10 and 11) is driven (motor running) (FIG. 2B).

(3) During steady running In an operating region where the internal combustion engine 2 has good engine efficiency, the vehicle travels mainly using power generated by the internal combustion engine 2. In such a case, the power generated by the internal combustion engine 2 is divided into an appropriate ratio by the power split mechanism 5 so that the power generated by the internal combustion engine 2 and the power generated by the motor 3 cooperate at an optimum ratio. Then, control is performed so as to drive the vehicle (drive wheels 10 and 11) (FIG. 2C).

  In addition, when shifting from (2) starting / light load traveling to (3) steady traveling, it is necessary to start the internal combustion engine 2 from the motor traveling state. This is performed by the motor 3 or the generator 4 cranking the internal combustion engine 2.

  Thus, the hybrid vehicle 100 drives the vehicle while controlling the sharing of the internal combustion engine 2 and the motor 3. Further, for example, since power supply from the internal combustion engine 2 is not required when the vehicle is started, the internal combustion engine 2 is automatically operated when the vehicle is stopped in order to improve fuel consumption and reduce the total exhaust gas emission amount. It is also possible to perform idle stop control to stop.

Here, a schematic configuration of the internal combustion engine 2 will be described with reference to FIG. The internal combustion engine 2 includes a plurality of cylinders, and each cylinder is loaded with a piston that is slidable in the axial direction. The piston is connected to a crankshaft 21 that is an engine output shaft via a connecting rod. A combustion chamber 22 is formed above the piston, and an opening end of an intake port 23 is formed in the combustion chamber 22. The opening end is opened and closed by an intake valve 24 attached to the internal combustion engine 2. The

  The intake port 23 communicates with an intake branch pipe 25 attached to the internal combustion engine 2, the intake branch pipe 25 is connected to a surge tank 26, and then the surge tank 26 is connected to an air cleaner box 28 via an intake pipe 27. Is done. A fuel injection valve 29 is attached to the intake branch pipe 25 so that its injection hole faces the intake port 23. The intake pipe 27 opens and closes an intake passage in the intake pipe 27 in conjunction with an accelerator pedal (not shown). A throttle valve 30 is provided.

  The internal combustion engine 2 is provided with a known crank position sensor 31 and a water temperature sensor 32 that outputs an electric signal corresponding to the temperature of the cooling water.

  The internal combustion engine 2 is supported on the vehicle body side 35 of the automobile by a variable engine mount 33, an engine mount 34, and the like. The variable engine mount 33 is an example of a variable vibration isolation bearing device according to the present invention. As shown in FIGS. 4 and 5, the outer cylinder fitting 41 having an open top and the inner diameter of the outer cylinder fitting 41 are substantially the same. A disc-shaped rigid body having an outer diameter of 10 mm, and a partition plate 42 for partitioning the interior of the outer cylinder fitting 41 into two upper and lower chambers, and an elastic body such as rubber, and is press-fitted into a space above the partition plate 42 for outer cylinder fittings. And a vibration isolating base 43 made of an elastic material such as rubber and press-fitted into a space below the partition plate 42 and fixed to the outer tube fitting 41.

  A space is formed above the partition plate 42 so as to be surrounded by the vibration isolation base 43 and the partition plate 42, and this space is separated from the space portion 46 and the space by a diaphragm 45 whose periphery is fixed to the partition plate 42. It is divided into a part 47. The space 46 is filled with liquid.

  A space 48 formed so as to be surrounded by the vibration isolating base 44 and the partition plate 42 is formed below the partition plate 42 of the variable engine mount 33, and the space 48 is filled with liquid. The The space 48 and the space 46 communicate with each other through an orifice 49 formed in the partition plate 42.

  Further, the partition plate 42 and the outer cylinder fitting 41 are formed with a communication passage 50 that communicates the space 47 and the outside. The communication passage 50 communicates with a vacuum switching valve (VSV) 36 shown in FIG. .

  As shown in FIG. 3, the VSV 36 is connected to the communication passage 50 and is connected to a passage 37 connected to the intake pipe 27 upstream from the throttle valve 30 and a passage 38 connected to the surge tank 26. The three-way valve includes a valve body that switches between communication between the variable engine mount 33 and the passage 37 (blocking of the passage 38) and communication between the variable engine mount 33 and the passage 38 (blocking of the passage 37), and the ECU 31. And a solenoid for driving the valve body in response to a control signal from. The solenoid uses a battery 8 mounted on the vehicle as a drive source.

  Then, when the variable engine mount 33 and the passage 37 are communicated with each other by the VSV 36, the atmosphere (pressure) flowing through the intake pipe 27 is introduced into the space 47 of the variable engine mount 33 as shown in FIG. At the same time as the volume of 47 is increased, the volume of the space 46 is reduced, and as a result, the pressure in the space 46 is increased.

On the other hand, when the variable engine mount 33 and the passage 38 are communicated with each other by the VSV 36, the intake negative pressure in the surge tank 26 is introduced into the space 47 of the variable engine mount 33 as shown in FIG. Then, the diaphragm 45 comes into close contact with the partition plate 42, the volume of the space 47 is reduced, and simultaneously the volume of the space 46 is increased. As a result, the pressure in the space 46 is reduced. .

  The hybrid vehicle 100 configured as described above includes the ECU 9. The ECU 9 includes a hybrid control computer (hereinafter referred to as “HVCC”) and an engine control computer (hereinafter referred to as “ECC”). I have. These HVCC and ECC are arithmetic and logic circuits composed of a CPU, ROM, RAM, backup RAM, and the like.

  Various sensors such as an accelerator position sensor (not shown) and a shift position sensor (not shown) attached to the hybrid vehicle 100 are connected to the HVCC via electric wiring, and output signals of the various sensors described above are input to the HVCC. It has come to be. The HVCC obtains a necessary internal combustion engine output based on detection values of various sensors and outputs a requested value to the ECC, and obtains a necessary torque (load torque or drive torque) to control the motor 3 and the generator 4. To do.

  In the ECC, various sensors such as the above-described crank position sensor 31, water temperature sensor 32, and vibration measurement sensor (which constitutes engine vibration detection means) 39 attached to the engine mount portion and measures the vibration of the internal combustion engine 2 are electrically wired. And the output signals of the various sensors described above are input to the ECC. Further, the VSV 36, the fuel injection valve 29, an igniter, and the like are connected to the ECC via electric wiring, and the operation state of the internal combustion engine 2 is determined from output signals from various sensors, and then the VSV 36 is determined according to the determined operation state. The fuel injection valve 29, the spark plug, etc. are controlled.

  In hybrid vehicle 100, since the start and stop of the internal combustion engine are frequently repeated, vibrations at the time of starting the internal combustion engine (under a condition where the engine speed is low) are suppressed from being transmitted to the vehicle body side. It will be necessary. Therefore, in the present embodiment, the following engine vibration suppression control is executed.

  In this engine vibration suppression control, the ECC in the ECU 9 controls the VSV 36 so as to reduce the vibration of the hybrid vehicle 100 by absorbing the vibration at the time of starting or idling of the internal combustion engine 2.

  Since the internal combustion engine 2 tries to rotate in the rotation direction (clockwise in FIG. 3) of the crankshaft 21 for each explosion stroke of each cylinder, a force in the compression direction is applied to the variable engine mount 33 at that time. . Therefore, the ECU 9 (ECC) controls the VSV 36 so that the variable engine mount 33 and the passage 38 communicate with each other when the vibration caused by the combustion of the air-fuel mixture in the internal combustion engine 2 needs to be absorbed. Is depressurized. As a result, the attenuation of the variable engine mount 33 increases, so that vibration in the compression direction is absorbed by the variable engine mount 33.

  On the other hand, when it is necessary to absorb the vibration caused by the combustion of the air-fuel mixture in the internal combustion engine 2, the ECU 9 (ECC) controls the VSV 36 so that the variable engine mount 33 and the passage 37 communicate with each other, and the space portion 46. Increase the pressure. As a result, since the attenuation of the variable engine mount 33 is reduced, vibrations in the compression direction are hardly absorbed, but the rotational torque of the crankshaft 21 starts to be transmitted to the drive wheels and the like quickly.

Hereinafter, the engine vibration suppression control according to the present embodiment will be specifically described with reference to the flowchart shown in FIG. This control routine is a routine that is stored in advance in the ROM of the ECU 9 (ECC), and is a routine that the ECU 9 executes as an interrupt process triggered by the passage of a fixed time or the input of a pulse signal from the crank position sensor 31. It is.

  In this routine, first, in step (hereinafter simply referred to as “S”) 101, it is determined whether or not the motor 3 is running alone. If an affirmative determination is made, the process proceeds to S102. If a negative determination is made, execution of this routine is terminated.

  In S102, it is determined whether or not there is a request to start the internal combustion engine 2. This is because there is a request for starting the internal combustion engine 2 when the accelerator is depressed when the vehicle is running only with a motor, such as when starting or running at a low speed, or when the state of charge of the battery 8 falls below a specified value. It is determined whether or not there is. If an affirmative determination is made, the process proceeds to S103, and if a negative determination is made, execution of this routine is terminated.

  In S103, the attenuation of the variable engine mount 33 is increased and the internal combustion engine 2 is started. That is, the ECU 9 controls the VSV 36 so that the variable engine mount 33 and the passage 38 communicate with each other, and depressurizes the space 46. In this state, the internal combustion engine 2 is started by causing the motor 3 or the generator 4 to crank the internal combustion engine 2.

  Thereafter, the process proceeds to S104, where it is determined whether or not the engine speed (Ne) calculated based on the output of the crank position sensor 31 is higher than a predetermined speed (Nef). If an affirmative determination is made, the process proceeds to S105, where the attenuation of the variable engine mount 33 is reduced. That is, the ECU 9 controls the VSV 36 so that the variable engine mount 33 and the passage 37 communicate with each other, and increases the pressure of the space 46. Thereafter, the process proceeds to S106, where the crankshaft 21 of the internal combustion engine 2 and the rotating shaft 3a of the motor 3 are connected via the power split mechanism 5, and the torque generated by the internal combustion engine 2 via the speed reducer 6 is applied to the drive wheels 10, 11. Communicate. The predetermined rotational speed (Nef) is determined even if the vibration of the internal combustion engine 2 is transmitted to the vehicle body side in a state where the VSV 36 is controlled to increase the pressure of the space 46 and the attenuation of the variable engine mount 33 is reduced. The engine speed is a rotational speed that is derived in advance through experiments or the like as the minimum value of the engine speed that does not give unpleasant vibrations to the user of the vehicle 100. For example, it can be 800 rpm.

  On the other hand, the process proceeds to S107 when it is determined in S104 that the engine speed is equal to or lower than the predetermined engine speed. In this step, it is determined whether or not the operation of the internal combustion engine 2 is stopped. That is, it is determined whether there is no request for starting the internal combustion engine 2 and cranking of the internal combustion engine 2 has been stopped halfway, or whether the operation has been stopped before the engine reaches the predetermined rotational speed.

  If the determination in step S107 is affirmative, the process proceeds to step S108, where the attenuation of the variable engine mount 33 is reduced as in step S105 described above, and the execution of this routine is terminated. On the other hand, if a negative determination is made in S107, the processing after S104 is performed again.

  By executing such engine vibration suppression control, when starting the internal combustion engine during motor travel that is frequently performed in the hybrid vehicle 100, until the torque generated by the internal combustion engine 2 starts to be transmitted to the drive wheels, When the attenuation of the variable engine mount 33 is increased and the torque of the internal combustion engine 2 is started to be transmitted to the drive wheels, the attenuation of the variable engine mount 33 is decreased. The timing for switching the attenuation of the variable engine mount 33 from large to small is set when the engine speed is higher than a predetermined speed. As a result, the vibration of the internal combustion engine transmitted to the vehicle body when starting the internal combustion engine is absorbed and reduced, and the vibration of the hybrid vehicle is reduced.

  Further, the predetermined rotational speed (Nef) may be corrected based on the temperature (water temperature) and / or the oil temperature of the cooling water of the internal combustion engine 2. Specifically, the correlation between the water temperature or the oil temperature and the correction value (ΔNef) of the predetermined rotational speed is obtained in advance by experiments or the like to create a map as shown in FIG. 7, and the process of S104 of the control routine is performed. At each execution, a correction value (ΔNef) is derived based on the map, and a predetermined rotational speed (Nef) is corrected (Nef → Nef + ΔNef). In addition, it is preferable that the map is created so that the predetermined rotational speed increases as the water temperature or the oil temperature decreases, for example. And it can suppress that a vibration varies according to the warming condition of the internal combustion engine 2 by doing in this way.

  Further, instead of the map as shown in FIG. 7, a correction value (ΔNef) is obtained using a three-dimensional map that is created by previously obtaining a correlation between the water temperature, the oil temperature, and the correction value (ΔNef) of the predetermined rotational speed through experiments or the like. ) May be derived, and the predetermined rotational speed (Nef) may be corrected based on the correction value. By doing in this way, it can suppress that a vibration varies according to warming condition more accurately.

  In the present embodiment, only the engine vibration suppression control is different from that of the first embodiment, and the others are the same, and the detailed description thereof is omitted.

  The engine vibration suppression control according to the present embodiment will be outlined. The timing at which the engine vibration suppression control according to the first embodiment switches the damping of the variable engine mount 33 from large to small is the time when the engine speed exceeds a predetermined speed, whereas the engine vibration suppression control according to the present embodiment. In the control, the vibration value of the internal combustion engine 2 that is a detection value of the vibration measurement sensor 39 provided in the internal combustion engine 2 is also taken into consideration, and when the detected vibration value is smaller than a predetermined value, the engine speed is increased. The attenuation of the variable engine mount 33 is switched from large to small even when the rotation speed is lower than the predetermined rotational speed. Then, the engine speed at the time when the detected vibration value becomes smaller than the predetermined value is set as the predetermined speed at the start of the internal combustion engine after the next time.

  Hereinafter, the engine vibration suppression control according to the present embodiment will be specifically described with reference to the flowchart shown in FIG. This control routine is a routine that is stored in advance in the ROM of the ECU 9 (ECC), and is a routine that the ECU 9 executes as an interrupt process triggered by the passage of a fixed time or the input of a pulse signal from the crank position sensor 31. It is.

  As shown in the flowcharts of FIGS. 6 and 8, in the control routine for engine vibration suppression control according to the present embodiment, the processing of S209 and S210 is performed with respect to the control routine for engine vibration suppression control according to the first embodiment. Since the processes of S201 to S208 are the same as the processes of S101 to S108 of the first embodiment, detailed description thereof will be omitted.

  In S209, it is determined whether or not the vibration value of the internal combustion engine 2 detected by the vibration measurement sensor 39 is smaller than a predetermined value. The predetermined value is the maximum value that does not give unpleasant vibration to the user of the hybrid vehicle 100 even if the VSV 36 is controlled to increase the space 46 and reduce the attenuation of the variable engine mount 33. It is a value derived in advance by experiments or the like.

  If the determination in step S209 is affirmative, the process proceeds to step S210, where the current rotational speed (Ne) of the internal combustion engine is set as the predetermined rotational speed (Nef) used for the processing in step S204, and then the processing from step S205 is executed.

  On the other hand, if a negative determination is made in S209, the processing after S204 is executed. That is, in S204, it is determined whether or not the engine speed (Ne) is higher than the predetermined engine speed (Nef), and if the determination is affirmative, the processing after S205 is executed and the determination is negative. Determines whether or not the operation of the internal combustion engine 2 has been stopped in S207. If an affirmative determination is made in S207, the process proceeds to S208, and if a negative determination is made, the processes from S209 onward are performed again.

  As described above, in the present control routine, when the internal combustion engine 2 is started, the variable engine mount 33 is greatly attenuated, and thereafter, the vibration value of the internal combustion engine 2 that is the detection value of the vibration measurement sensor 39 is predetermined. Attenuation of the variable engine mount 33 after the state becomes smaller than the value (the state in which an affirmative determination is made in S209) or the engine speed exceeds the predetermined number of rotations (the state in which an affirmative determination is made in S204). After that, the torque of the internal combustion engine 2 is started to be transmitted to the drive wheels.

  In other words, in the hybrid vehicle 100 according to the present embodiment, at the time of starting the internal combustion engine during motor running that is frequently performed in the hybrid vehicle, until the torque generated by the internal combustion engine 2 is started to be transmitted to the drive wheels, When the attenuation of the variable engine mount 33 is increased and the torque of the internal combustion engine 2 is started to be transmitted to the drive wheels, the attenuation of the variable engine mount 33 is decreased. The timing for switching the attenuation of the variable engine mount 33 from large to small is a state where the vibration value of the internal combustion engine 2 detected by the vibration measurement sensor 39 is smaller than a predetermined value, or the engine speed exceeds the predetermined speed. The point in time is one of the states. And by these, the vibration of the internal combustion engine transmitted to the vehicle body side when starting the internal combustion engine is absorbed and reduced, and the vibration of the hybrid vehicle is reduced.

  If it is determined in S204 that the engine speed is equal to or lower than the predetermined engine speed (Nef) and it is determined in S207 that the operation of the internal combustion engine 2 has not been stopped, the processes after S209 are executed again. If the vibration value of the internal combustion engine 2 is smaller than the predetermined value during the process of S209, even if the engine speed is equal to or lower than the predetermined engine speed (Nef), the process of S205 causes the variable engine mount 33 to be Attenuation is reduced. At that time, the engine speed at the time when the vibration value of the internal combustion engine 2 becomes smaller than a predetermined value is set (learned) as the predetermined speed (Nef) used in the process of S204. Become.

  Thereby, in the flow after the next time, when the hybrid vehicle 100 travels on a rough road, the vibration measurement sensor 39 is difficult to accurately detect the value resulting from the combustion of the air-fuel mixture of the internal combustion engine 2. In this case, when the engine speed becomes higher than the learned predetermined speed, the attenuation of the variable engine mount 33 is reduced, and the torque of the internal combustion engine 2 is transmitted to the drive wheels. As a result, the torque of the internal combustion engine 2 is transmitted to the drive wheels at an earlier stage than in the case where the predetermined rotational speed is kept at the initially set value without learning, so that the acceleration performance can be improved.

  Further, as described in the first embodiment, the predetermined rotation speed (Nef) may be corrected based on the temperature (water temperature) and / or oil temperature of the cooling water of the internal combustion engine 2. That is, a correction value (ΔNef) is derived based on a map as shown in FIG. 7 that is created in advance every time the process of S204 of the control routine is executed, and the predetermined rotation speed (Nef) is corrected (Nef → Nef + ΔNef). Alternatively, instead of the map as shown in FIG. 7, a correction value (ΔNef) is obtained using a three-dimensional map that is created by previously obtaining a correlation between the water temperature, the oil temperature, and the correction value (ΔNef) of the predetermined rotational speed through experiments or the like. ) May be derived, and the predetermined rotational speed (Nef) may be corrected based on the correction value. By doing in this way, it can suppress that a vibration varies according to the warming-up condition of the internal combustion engine 2.

1 is a diagram illustrating a schematic configuration of a hybrid vehicle according to a first embodiment. 1 is a schematic diagram illustrating a transmission path of power and electric power of a hybrid system in a hybrid vehicle according to a first embodiment. 1 is a diagram illustrating a schematic configuration of an internal combustion engine according to a first embodiment. It is a figure which shows schematic structure of the variable engine mount (variable anti-vibration bearing apparatus) which concerns on Example 1. FIG. It is a figure explaining operation | movement of the variable engine mount (variable anti-vibration bearing apparatus) which concerns on Example 1. FIG. 3 is a flowchart of a control routine for engine vibration suppression control according to the first embodiment. It is the figure which showed the relationship between the water temperature or oil temperature in engine vibration suppression control, and the correction value of an engine speed. 9 is a flowchart of a control routine for engine vibration suppression control according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid system 2 Internal combustion engine 3 Motor 4 Generator 5 Power split mechanism 6 Reducer 7 Inverter 8 Battery 9 ECU
30 Water temperature sensor 31 Crank position sensor 33 Variable engine mount (variable anti-vibration bearing device)
36 VSV
39 Vibration sensor

Claims (2)

An internal combustion engine having a variable vibration isolation bearing device, a motor, and engine vibration detection means for detecting vibrations of the internal combustion engine, and driven by using at least one of the internal combustion engine and the motor as a drive source In a control method for starting an internal combustion engine of a hybrid vehicle that drives wheels,
From the start of the internal combustion engine to the state where the vibration of the internal combustion engine detected by the engine vibration detecting means is smaller than a predetermined value or the state where the rotational speed of the internal combustion engine exceeds the predetermined rotational speed Increases the damping of the variable vibration isolation bearing device than after entering the state ,
If the internal combustion engine vibration detected by the engine vibration detection means before the rotational speed of the internal combustion engine exceeds the predetermined rotational speed is smaller than the predetermined value, rotational speed of the internal combustion engine, characterized and to Ruha hybrid internal combustion engine start control method for a vehicle to be set as the predetermined rotational speed at the start of the next and subsequent engine. 2. The control method for starting an internal combustion engine of a hybrid vehicle according to claim 1 , wherein the predetermined rotational speed is corrected in accordance with a temperature of cooling water and / or oil of the internal combustion engine.

Images