Hybrid vehicle control device

Abstract

To provide a hybrid vehicle control device comprising an engine having a super charger and a blow-by gas processor and an electric motor as a driving source, by which it is suppressed that moisture content in a blow-by gas is condensed and freezed and ices are formed.SOLUTION: A HEV-CU80 regeneratively controls an electric motor 11 without reducing an output torque of an engine 10 (that is, so as to prevent a boost pressure from becoming negative pressure) in at least any one of the case that a boost pressure drops below a prescribed threshold and the case that an accelerator opening degree decreases in the state that an outside air temperature is a prescribed temperature or less and the boost pressure is a positive pressure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle, and more particularly to a control device for a hybrid vehicle that is provided with an engine having a supercharger and a blow-by gas treatment device, and an electric motor as drive sources. [Background technology]

[0002] In recent years, hybrid electric vehicles (HEVs) have become widely used, as they can effectively improve the fuel consumption rate (fuel economy) of vehicles by using both an engine and an electric motor (motor-generator).

[0003] In addition, in order to prevent blow-by gas that has leaked into the crankcase from between the cylinder and piston from being released into the environment (atmosphere), blow-by gas treatment devices have been widely used that return the blow-by gas to the engine's intake system, where it is burned and treated (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-173548 Summary of the Invention [Problem to be solved by the invention]

[0005] In an engine equipped with a supercharger such as a turbocharger, the supercharging pressure (boost pressure) changes depending on the amount of depression of the accelerator pedal (accelerator opening). For example, when the accelerator pedal is depressed, the supercharging pressure (intake pressure), which was initially negative, increases and becomes positive in response to the depression of the accelerator pedal.

[0006] Here, for example, in an extremely low-temperature environment of -20°C or below, if the accelerator pedal is repeatedly depressed and released (released) near the point where the boost pressure switches from positive to negative, the fresh air line that connects the upstream of the turbocharger with the crankcase, etc. and introduces fresh air (outside air) will repeatedly flow forward and backward, causing the cold outside air (fresh air) to mix with the warm, moist blow-by gas inside the engine, causing the moisture in the blow-by gas to condense and freeze, forming ice.

[0007] The present invention has been made to solve the above problems, and aims to provide a control device for a hybrid vehicle that has an engine with a turbocharger and a blow-by gas treatment device and an electric motor as drive sources, and that is capable of preventing water in the blow-by gas from condensing and freezing to form ice. [Means for solving the problem]

[0008] A control device for a hybrid vehicle according to one aspect of the present invention is a control device for a hybrid vehicle that includes an engine having a blow-by gas treatment device that introduces blow-by gas into the intake system and burns it, the blow-by gas treatment device including a turbocharger and a ventilation line that connects the crankcase to the downstream of the turbocharger and returns blow-by gas to the intake system, and a fresh air line that connects the upstream of the turbocharger to the crankcase and introduces fresh air, an electric motor connected to the output shaft of the engine so as to be able to transmit torque, and a control unit that controls the drive of the engine and the electric motor, and is characterized in that the control unit regenerates the electric motor without reducing the output torque of the engine when, when the outside air temperature is below a predetermined temperature and the boost pressure is positive, the boost pressure drops below a predetermined threshold value, or when the accelerator opening is reduced. [Effects of the Invention]

[0009] According to the present invention, in a control device for a hybrid vehicle that has an engine with a turbocharger and a blow-by gas treatment device and an electric motor as drive sources, it is possible to prevent water in the blow-by gas from condensing and freezing to form ice. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a configuration of a control device for a hybrid vehicle according to an embodiment, and a hybrid vehicle to which the control device is applied; [Figure 2] 1 is a diagram showing the configuration of an engine mounted on a hybrid vehicle according to an embodiment; [Figure 3] 4 is a flowchart showing a processing procedure for motor control associated with blow-by gas processing by the control device for the hybrid vehicle according to the embodiment; [Figure 4] FIG. 4 is a diagram showing an example of a target motor torque map. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and redundant explanations will be omitted.

[0012] First, the configuration of a control device for a hybrid vehicle according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing the configuration of a control device for a hybrid vehicle and a hybrid vehicle to which the control device is applied. Figure 2 is a diagram showing the configuration of an engine 10 mounted on the hybrid vehicle. Note that the description will be given here taking as an example a case where the control device for a hybrid vehicle is mounted on a series-parallel hybrid vehicle (HEV).

[0013] First, the configuration of a hybrid vehicle will be described with reference to Figure 1. A power split device 30 is connected to a crankshaft 10a of an engine 10 (details of which will be described later) via a flywheel damper 20, which absorbs rotational fluctuations of the engine 10, and a pair of gears 21. A drive train 15, which is made up of multiple gears, shafts, etc. and transmits torque between the drive wheels, and a first motor-generator (MG) 11 (corresponding to the electric motor in the claims) are connected to the power split device 30. The power split device 30 has a planetary gear mechanism made up of, for example, a sun gear 30a, a ring gear 30b, a pinion gear 30c, and a planetary carrier 30d, and divides and transmits drive torque generated by the engine 10 to the drive train 15 and the first motor-generator 11.

[0014] More specifically, the carrier 30d is connected to the crankshaft 10a of the engine 10 via the flywheel damper 20 and a pair of gears 21. The sun gear 30a is connected to the first motor-generator 11. Meanwhile, the ring gear 30b is connected to a propeller shaft 50 that constitutes the drive train 15 via a pair of gears (counter gears) 31, and is further connected to a front drive shaft 60 via a drive reduction gear 43.

[0015] When the first motor-generator 11 functions as a generator, the power distribution mechanism 30 distributes the torque (driving force) from the engine 10 input through the planetary carrier 30d to the sun gear 30a and the ring gear 30b according to the gear ratios of the two. On the other hand, when the first motor-generator 11 functions as a motor, the power distribution mechanism 30 combines the torque from the engine 10 input through the planetary carrier 30d and the torque from the first motor-generator 11 input through the sun gear 30a, and outputs the combined torque to the ring gear 30b. The torque output to the ring gear 30b is output to a propeller shaft 50 that constitutes the drive train 15 via a pair of gears (counter gears) 31, and is also output to a front drive shaft 60 via a drive reduction gear 43.

[0016] Meanwhile, a second motor-generator (MG) 12 (corresponding to the electric motor recited in the claims) is also connected to the drive train 15. More specifically, the second motor-generator 12 is connected to a propeller shaft 50 via a motor reduction gear 41. The second motor-generator 12 is also connected to a front drive shaft 60 via a drive reduction gear mechanism 40 composed of the motor reduction gear 41 and a drive reduction gear 43. The front drive shaft 60 transmits torque to the front wheels. The propeller shaft 50 transmits torque to the rear wheels.

[0017] The first motor-generator 11 and the second motor-generator 12 are configured as synchronous generator-motors that combine the function of a motor that converts supplied electric power into mechanical power and the function of a generator that converts input mechanical power into electric power. That is, the first motor-generator 11 and the second motor-generator 12 each operate as a motor that generates drive torque when driving the vehicle, and as a generator when regenerating. The first motor-generator 11 mainly operates as a generator, and the second motor-generator 12 mainly operates as a motor.

[0018] The driving reduction gear mechanism 40 is configured to have a motor reduction gear 41 and a driving reduction gear 43. The motor reduction gear 41 is configured as a planetary gear, and the reduction gear 43 is configured as, for example, a spur gear (or a helical gear).

[0019] More specifically, the motor reduction gear 41 has a planetary gear mechanism including, for example, a sun gear 41a, a ring gear 41b, a pinion gear 41c, and a planetary carrier 41d. When the second motor-generator 12 functions as a motor, the motor reduction gear 41 decelerates the rotation transmitted from the second motor-generator 12 (increases the torque) and outputs it from the planetary carrier 41d. On the other hand, the motor reduction gear 41 accelerates the rotation due to the torque (driving force) input to the planetary carrier 41d (reduces the torque) and outputs it from the sun gear 41a, thereby causing the second motor-generator 12 to function as a generator.

[0020] The front drive shaft 60 transmits torque between the drive reduction gear mechanism 40 and the drive wheels (front wheels in the example of FIG. 1). More specifically, the torque transmitted to the front drive shaft 60 is transmitted to a front differential (hereinafter also referred to as "front diff") 62. The front diff 62 is, for example, a bevel gear type differential device. The torque from the front diff 62 is transmitted to a left front wheel (not shown) via a left front wheel drive shaft, and to a right front wheel (not shown) via a right front wheel drive shaft.

[0021] On the other hand, propeller shaft 50 transmits torque to the rear wheels. A transfer clutch 51 is installed on propeller shaft 50 to adjust the torque transmitted to the rear wheels. Transfer clutch 51 controls the engagement force (i.e., torque distribution rate to the rear wheels) depending on the drive state of the four wheels (for example, slip state of the front wheels), engine torque, etc. Therefore, the torque transmitted to propeller shaft 50 is distributed according to the engagement force of transfer clutch 51 and transmitted to the rear wheels as well.

[0022] More specifically, torque is transmitted to propeller shaft 50 and adjusted (distributed) by transfer clutch 51, and then transmitted to rear differential (hereinafter also referred to as "rear diff") 52. A left rear wheel drive shaft and a right rear wheel drive shaft (not shown) are connected to rear differential 52. Driving force from rear differential 52 is transmitted to the left rear wheel (not shown) via the left rear wheel drive shaft, and to the right rear wheel (not shown) via the right rear wheel drive shaft.

[0023] Because of this configuration, the vehicle (AWD HEV vehicle) according to this embodiment can drive the front and rear wheels (vehicle) with power from the engine 10 and the second motor-generator 12, etc. Furthermore, depending on the driving conditions, it is possible to switch between driving only by the second motor-generator 12 (EV driving) and driving by the engine 10 and the second motor-generator 12, etc. Furthermore, it is also possible to generate electricity (regenerate) with the first motor-generator 11, etc.

[0024] The engine 10, which is the driving force source of the vehicle, and the second motor-generator 12 and first motor-generator 11 are comprehensively controlled by a hybrid vehicle control unit (hereinafter referred to as "HEV-CU") 80.

[0025] HEV-CU80 is configured with a microprocessor that performs calculations, an EEPROM that stores programs and the like that cause the microprocessor to execute various processes, a RAM that stores various data such as calculation results, a backup RAM in which the stored contents are retained, and an input / output I / F, etc.

[0026] Various sensors are connected to the HEV-CU80, including, for example, an accelerator opening sensor 91 that detects the amount of depression of the accelerator pedal, i.e., the opening (operation amount) of the accelerator pedal, a throttle opening sensor 92 that detects the opening of the throttle valve, an outside air temperature sensor 93 that detects the outside air temperature, an intake pressure sensor (corresponding to the supercharging pressure sensor described in the claims) 94 that detects the pressure inside the intake manifold 111 (intake manifold pressure) described below, a rotation speed sensor 95 that detects the rotation speed of the front drive shaft 60, a resolver 97 that detects the rotation speed (rotational speed) of the first motor-generator 11, and a resolver 98 that detects the rotation speed (rotational speed) of the second motor-generator 12.

[0027] Furthermore, the HEV-CU 80 is connected via a CAN (Controller Area Network) 70 to an engine control unit (hereinafter referred to as "ECU") 81 that controls the engine 10, a vehicle dynamics control unit (hereinafter referred to as "VDCU") 85 that improves driving stability by suppressing skidding of the vehicle, and other such units so that they can communicate with each other. The HEV-CU 80 receives various information, such as engine speed and brake operation amount, from the ECU 81 and the VDCU 85 via the CAN 70. Meanwhile, the HEV-CU 80 transmits various information, such as the rotation speed (rotational speed) of the first motor-generator 11 and the rotation speed (rotational speed) of the second motor-generator 12, to the ECU 81 via the CAN 70.

[0028] Based on the various types of information acquired, the HEV-CU 80 comprehensively controls the driving of the engine 10, the second motor-generator 12, and the first motor-generator 11. The HEV-CU 80 calculates and outputs the required output of the engine 10 and torque command values ​​(target motor torque) for the second motor-generator 12 and the first motor-generator 11 based on, for example, the accelerator opening (drive force required by the driver), the vehicle operating state, and the state of charge (SOC: State Of Charge) of the high-voltage battery 90 (corresponding to the storage battery in the claims).

[0029] A power control unit (hereinafter referred to as "PCU") 82 drives the second motor-generator 12 and the first motor-generator 11 via an inverter 82a based on the torque command value. The PCU 82 has an inverter 82a that converts DC power from a high-voltage battery 90 into three-phase AC power and supplies it to the second motor-generator 12 and the first motor-generator 11. As described above, the PCU 82 drives the second motor-generator 12 and the first motor-generator 11 via the inverter 82a based on the torque command value received from the HEV-CU 80. Meanwhile, during regeneration, the inverter 82a converts AC voltage generated by the first motor-generator 11 and the second motor-generator 12 into DC voltage to charge the high-voltage battery 90.

[0030] Furthermore, the ECU 81 adjusts, for example, the opening of the electronically controlled throttle valve 113 based on the required output.

[0031] Next, the configuration of the engine 10 mounted on the hybrid vehicle will be described in detail with reference to FIG.

[0032] The engine 10 is, for example, a horizontally opposed four-cylinder gasoline engine equipped with a turbocharger 140 (corresponding to a supercharger in the claims). An intake pipe (intake passage) 115 of the engine 10 is arranged with, from the upstream side, an air cleaner 116, an air flow meter 114, the turbocharger 140, an intercooler 146, an electronically controlled throttle valve (hereinafter also simply referred to as a "throttle valve") 113, and the like.

[0033] Turbocharger 140 is a supercharger that is arranged between intake pipe 115 and exhaust pipe (exhaust passage) 118 and performs supercharging. Turbocharger 140 has a turbine 142 that is provided in exhaust pipe 118, and a compressor 141 that is provided in intake pipe 115 and connected to turbine 142 by a rotary shaft 143, and by driving turbine 142 with exhaust energy, air is compressed by compressor 141 that is coaxial with turbine 142.

[0034] The intercooler 146 cools, by heat exchange, the intake air that has been compressed and heated by the turbocharger 140 (compressor 141). A throttle valve 113 that adjusts the amount of intake air is disposed downstream of the intercooler 146.

[0035] In engine 10, air is taken in through air cleaner 116 and supercharged by turbocharger 140 as necessary, throttled by throttle valve 113, passes through intake manifold 111, and is taken into each cylinder formed in engine 10. The amount of air taken in through air cleaner 116 (the amount of air taken into engine 10) is detected by air flow meter 114 disposed between air cleaner 116 and throttle valve 113. An intake pressure sensor (supercharging pressure sensor) 94 that detects the pressure inside intake manifold 111 (intake manifold pressure) is disposed inside a collector section (surge tank) that constitutes intake manifold 111. Furthermore, a throttle opening sensor 92 that detects the opening of throttle valve 113 is disposed in throttle valve 113.

[0036] The cylinder head has an intake port and an exhaust port for each cylinder. Each intake port and exhaust port is provided with an intake valve and an exhaust valve that open and close the intake port, respectively. A variable valve timing mechanism 126 is disposed between the intake camshaft, which drives the intake valve, and the intake cam pulley. The variable valve timing mechanism 126 rotates the intake cam pulley and the intake camshaft relatively to each other, continuously changing the rotational phase (displacement angle) of the intake camshaft with respect to the crankshaft 10a, thereby advancing or retarding the valve timing (opening / closing timing) of the intake valve. The variable valve timing mechanism 126 variably sets the opening and closing timing of the intake valve according to the engine operating conditions.

[0037] Similarly, a variable valve timing mechanism 127 is disposed between the exhaust camshaft and the exhaust cam pulley, which rotates the exhaust cam pulley and the exhaust camshaft relative to each other to continuously change the rotational phase (displacement angle) of the exhaust camshaft with respect to the crankshaft 10a, thereby advancing or retarding the valve timing (opening / closing timing) of the exhaust valve. The variable valve timing mechanism 127 variably sets the opening / closing timing of the exhaust valve according to the engine operating state.

[0038] An injector 112 that injects fuel into the cylinder is attached to each cylinder of the engine 10. The injector 112 injects fuel pressurized by a high-pressure fuel pump 160 directly into the combustion chamber of each cylinder.

[0039] The injectors 112 are connected to a delivery pipe 161. The delivery pipe 161 distributes fuel that has been pumped from a high-pressure fuel pump 160 through a fuel pipe 162 to each injector 112. The high-pressure fuel pump 160 pressurizes the fuel that has been sucked up from a fuel tank 180 by a feed pump (low-pressure fuel pump) 164 to a high pressure (for example, 8 to 13 MPa) depending on the operating state, and supplies the fuel to the delivery pipe 161. In this embodiment, a type that is driven by a camshaft of the engine 10 is used as the high-pressure fuel pump 160.

[0040] A spark plug 117 that ignites the air-fuel mixture and an igniter-integrated coil 121 that applies high voltage to the spark plug 117 are attached to the cylinder head of each cylinder. In each cylinder of the engine 10, the air-fuel mixture of intake air and fuel injected by the injector 112 is ignited by the spark plug 117 and combusted. Exhaust gas after combustion is discharged through an exhaust pipe 118.

[0041] A turbine 142 that constitutes a turbocharger 140 is provided downstream of the collection section of the exhaust pipe (exhaust passage) 118. The turbocharger 140 is provided with a wastegate 144 that bypasses exhaust gas from the inlet side to the outlet side of the turbine 142, and a wastegate valve 144a that opens and closes the wastegate 144. The opening degree of the wastegate valve 144a is controlled by the ECU 81 to adjust the boost pressure.

[0042] An air-fuel ratio sensor 119A that outputs a signal corresponding to the oxygen concentration in the exhaust gas is attached downstream of the turbine 142. A linear air-fuel ratio sensor (LAF sensor) that can linearly detect the exhaust air-fuel ratio is used as the air-fuel ratio sensor 119A. Note that an O2 sensor that detects the exhaust air-fuel ratio in an on-off manner may also be used as the air-fuel ratio sensor 119A.

[0043] Further, a front exhaust purification catalyst (CAT) 201 is disposed downstream of the air-fuel ratio sensor 119A. The exhaust purification catalyst 201 is a three-way catalyst that simultaneously oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and reduces nitrogen oxides (NOx), thereby purifying harmful gas components in the exhaust gas into harmless carbon dioxide (CO2), water vapor (H2O), and nitrogen (N2). Downstream of the front exhaust purification catalyst 201, a rear (post-CAT) O2 sensor 119B that detects the exhaust air-fuel ratio on and off, and a rear exhaust purification catalyst (CAT) 202 are provided.

[0044] The engine 10 also has a blow-by gas treatment device 170 that introduces blow-by gas that has leaked into the crankcase from the combustion chamber through between the cylinder and the piston into the intake system and combusts it. The blow-by gas treatment device 170 is mainly configured to include a ventilation line (PCV line) 171 that connects the inside of the crankcase with the downstream side (e.g., intake manifold 111) of the turbocharger 140 (compressor 141) and returns (introduces) the blow-by gas to the intake system, a PCV (Positive Crankcase Ventilation) valve 172 that adjusts the flow rate of the blow-by gas flowing through the ventilation line (PCV line) 171, and a fresh air line 173 that connects the upstream side (e.g., pre-turbo duct) of the turbocharger 140 (compressor 141) with the inside of the crankcase and introduces fresh air.

[0045] In this embodiment, the PCV valve 172 is of a type that operates according to the pressure difference between the crankcase and the downstream side (eg, intake manifold 111) of the turbocharger 140 (compressor 141), for example.

[0046] In addition to the above-mentioned air flow meter 114, LAF sensor 119A, O2 sensor 119B, etc., a cam angle sensor for identifying the cylinders of engine 10 is attached near the camshaft of engine 10. Also, a crank angle sensor 133 for detecting the rotational position of crankshaft 10a is attached near the crankshaft 10a of engine 10. Here, a timing rotor 133a having, for example, 34 protrusions with two teeth missing, formed at 10° intervals, is attached to the end of crankshaft 10a. Crank angle sensor 133 detects the rotational position of crankshaft 10a by detecting the presence or absence of the protrusions on timing rotor 133a. The cam angle sensor and crank angle sensor 133 may be, for example, an electromagnetic pickup type.

[0047] These sensors are connected to the ECU 81. In addition, various sensors such as a water temperature sensor 134 that detects the temperature of the coolant for the engine 10 and an oil temperature sensor 135 that detects the temperature of the lubricating oil are also connected to the ECU 81. The ECU 81 also receives information such as the required output, the number of revolutions (rotational speed) of the first motor-generator 11, the number of revolutions (rotational speed) of the second motor-generator 12, and the accelerator opening degree from the HEV-CU 80 via the CAN 70.

[0048] The ECU 81 is configured to include a microprocessor that performs calculations, an EEPROM that stores programs and the like for causing the microprocessor to execute various processes, a RAM that stores various data such as calculation results, a backup RAM in which the stored contents are maintained by a battery, an input / output I / F, etc. The ECU 81 also includes an injector driver that drives the injector 112, an output circuit that outputs an ignition signal, and a motor driver that drives an electric motor 113a that opens and closes the electronically controlled throttle valve 113.

[0049] The ECU 81 identifies the cylinder from the output of the cam angle sensor, and determines the rotational angular velocity and engine speed from the output of the crank angle sensor 133. The ECU 81 also acquires various information such as the intake air amount, the air-fuel ratio of the mixture, and the water temperature and oil temperature of the engine 10 based on detection signals input from the various sensors described above. The ECU 81 then controls the engine 10 by controlling the fuel injection amount, ignition timing, and various devices such as the throttle valve 113 and the wastegate valve 44 based on the required output from the HEV-CU 80 and the acquired various information.

[0050] The HEV-CU 80 has a function of preventing the moisture in the blow-by gas from condensing and freezing to form ice. That is, the HEV-CU 80 functions as a control unit as described in the claims. In the HEV-CU 80, this function is realized by a microprocessor executing a program stored in an EEPROM or the like.

[0051] Therefore, when the outside air temperature is below a predetermined temperature (e.g., -20°C) and the boost pressure (intake pressure) is positive (>atmospheric pressure), if the boost pressure drops below a predetermined threshold value, or if the accelerator opening decreases (e.g., drops by more than a predetermined value), the HEV-CU80 performs regenerative control of the first motor / generator 11, etc. without reducing the output torque of the engine 10 (so as not to reduce it, i.e., so that the boost pressure does not become negative pressure).

[0052] At this time, HEV-CU80 sets the target regeneration amount (target motor torque) of the first motor-generator 11, etc., based on the boost pressure and the rate of change of the accelerator pedal position. Here, for example, a map (target motor torque map) that defines the relationship between the boost pressure, the rate of change of the accelerator pedal position, and the target regeneration amount (target motor torque) of the first motor-generator 11, etc. is stored in the EEPROM of HEV-CU80, and the target motor torque map is searched based on the boost pressure and the rate of change of the accelerator pedal position to determine the target regeneration amount (target motor torque) of the first motor-generator 11.

[0053] An example of a target motor torque map is shown in Figure 4. In Figure 4, the horizontal axis represents boost pressure (kPa) and the vertical axis represents the rate of change of accelerator opening (deg / s). In the target motor torque map, a target motor torque (kW) is given for each combination (grid point) of boost pressure and rate of change of accelerator opening.

[0054] Furthermore, it is preferable that the HEV-CU 80 regenerates the first motor-generator 11 etc. only when the SOC (state of charge) of the high-voltage battery (storage battery) 90 that supplies power to the first motor-generator 11 etc. is below a predetermined threshold value (upper limit, for example, 80%).

[0055] On the other hand, during regeneration of the first motor-generator 11, etc., the HEV-CU80 stops regeneration of the first motor-generator 11, etc. in at least one of the following cases (when the condition is met): when the supercharging pressure becomes equal to or higher than a first predetermined pressure, when the supercharging pressure (boost pressure) becomes equal to or lower than a second predetermined pressure, when the accelerator opening (or the increase in accelerator opening per unit time) becomes equal to or higher than a first predetermined value, or when the accelerator opening (or the decrease in accelerator opening per unit time) becomes equal to or lower than a second predetermined value.

[0056] Furthermore, it is preferable that the HEV-CU 80 stops regeneration of the first motor-generator 11, etc. when the SOC of the high-voltage battery 90 that supplies power to the first motor-generator 11, etc., reaches or exceeds a predetermined threshold value (upper limit, for example, 80%).

[0057] When the outside air temperature is below a predetermined temperature (for example, -20°C) and the boost pressure (intake pressure) is positive (>atmospheric pressure), if the boost pressure is below a predetermined threshold and the accelerator opening increases, or if the SOC of the high-voltage battery 90 is above a predetermined value, the HEV-CU 80 preferably powers (assists) the first motor-generator 11 or the like, or increases the amount of powering (assistance). By lowering the SOC of the high-voltage battery 90 in advance, it is possible to avoid a situation in which the SOC of the high-voltage battery 90 reaches its upper limit during the processing of blow-by gas, making it impossible to perform regeneration associated with the processing of blow-by gas.

[0058] Next, the operation of the control device for the hybrid vehicle will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the procedure for motor control associated with blow-by gas processing by the control device for the hybrid vehicle. This process is repeatedly executed at predetermined timings in HEV-CU 80.

[0059] In step S100, a determination is made as to whether the outside air temperature is equal to or lower than a predetermined temperature (for example, -20°C). If the outside air temperature is equal to or lower than the predetermined temperature, the process proceeds to step S102. On the other hand, if the outside air temperature is higher than the predetermined temperature, the process temporarily ends.

[0060] In step S102, it is determined whether the supercharging pressure (boost pressure) is positive. If the supercharging pressure is positive, the process proceeds to step S104. On the other hand, if the supercharging pressure is negative, the process temporarily exits.

[0061] In step S104, it is determined whether the accelerator opening has decreased (decreased by a predetermined value or more). If the accelerator opening has decreased, the process proceeds to step S106. On the other hand, if the accelerator opening has not decreased, the process proceeds to step S200.

[0062] In step S106, it is determined whether the supercharging pressure (boost pressure) has fallen below a first threshold value. If the supercharging pressure has fallen below the first threshold value, the process proceeds to step S108. On the other hand, if the supercharging pressure has not fallen below the first threshold value, the process temporarily exits.

[0063] In step S108, it is determined whether the SOC of the high-voltage battery 90 is equal to or less than a threshold value. If the SOC of the high-voltage battery 90 is equal to or less than the threshold value, the process proceeds to step S110. On the other hand, if the SOC of the high-voltage battery 90 is higher than the threshold value, the process temporarily exits.

[0064] In step S110, regeneration is performed by the first motor-generator 11 etc., and control is performed so as not to change the output of the engine 10. The target motor torque (target regeneration amount) at this time is determined by a map (target motor torque map) that defines the relationship between the target motor torque and the rate of change of the supercharging pressure (boost pressure) and the accelerator opening.

[0065] Next, in step S112, a determination is made as to whether the regeneration stop conditions are satisfied. More specifically, a determination is made as to whether the SOC of the high-voltage battery 90 is equal to or greater than a predetermined value, whether the supercharging pressure (boost pressure) is greater than a first predetermined pressure, whether the supercharging pressure (boost pressure) is less than a second predetermined pressure, whether the accelerator opening is equal to or greater than a first predetermined value, or whether the accelerator opening is equal to or less than a second predetermined value. If at least one of these conditions is satisfied, the regeneration control associated with the processing of blow-by gas is stopped. On the other hand, if all of the above conditions are not satisfied, the process proceeds to step S110 described above, and this process (regeneration control) continues until at least one of the above conditions is satisfied.

[0066] In step S200, it is determined whether the accelerator opening has increased (by a predetermined value or more). If the accelerator opening has increased, the process proceeds to step S202. On the other hand, if the accelerator opening has not increased, the process temporarily exits.

[0067] In step S202, it is determined whether the SOC of the high-voltage battery 90 is equal to or greater than a predetermined value. If the SOC of the high-voltage battery 90 is equal to or greater than the predetermined value, the process proceeds to step S204. On the other hand, if the SOC of the high-voltage battery 90 is less than the predetermined value, the process temporarily exits.

[0068] In step S204, power running (assist) by the first motor-generator 11 etc. is performed, or the amount of power running (assist) is increased, and then the process ends.

[0069] As described above in detail, according to this embodiment, when the outside air temperature is below a predetermined temperature and the boost pressure is positive (>atmospheric pressure), and at least one of the following occurs: the boost pressure drops below a predetermined threshold value; and the accelerator pedal stroke decreases. The first motor-generator 11 and other components are regeneratively controlled without reducing the output torque of the engine 10 (so as not to reduce the output torque, i.e., so as not to cause the boost pressure to become negative). Therefore, even if the accelerator pedal is repeatedly depressed and released around the time when the boost pressure switches between positive and negative in an extremely low-temperature environment, for example, below -20°C, the boost pressure is prevented from changing from positive to negative. This prevents the fresh air line 173, which connects the upstream of the turbocharger with the crankcase and introduces fresh air (outside air), from repeatedly flowing forward and backward. This prevents the cold outside air (fresh air) from mixing with the warm, moist blow-by gas inside the engine. As a result, it is possible to prevent the moisture in the blow-by gas from condensing and freezing to form ice. Furthermore, since the first motor-generator 11 and the like are regenerative, it is possible to output torque that matches the torque required by the driver to the tires without reducing the engine torque (without reducing the boost pressure).

[0070] Furthermore, according to this embodiment, when the SOC of the high-voltage battery 90 is equal to or lower than a predetermined threshold, regeneration of the first motor-generator 11, etc. is performed, so that overcharging of the high-voltage battery 90 can be prevented.

[0071] On the other hand, according to this embodiment, during regeneration by the first motor-generator 11, etc., if the boost pressure becomes equal to or higher than a first predetermined pressure, if the boost pressure becomes equal to or lower than a second predetermined value, if the accelerator opening (or the increase in the accelerator opening per unit time) becomes equal to or higher than a first predetermined value, or if the accelerator opening (or the decrease in the accelerator opening per unit time) becomes equal to or lower than a second predetermined value, regeneration by the first motor-generator 11, etc. is stopped. Therefore, for example, if it is determined that the driver is requesting a sudden deceleration or acceleration, regeneration can be stopped in accordance with the driver's wishes. This makes it possible to prevent deterioration of drivability.

[0072] According to this embodiment, when the outside air temperature is below a predetermined temperature and the supercharging pressure is positive (>atmospheric pressure), if the accelerator opening increases while the supercharging pressure (boost pressure) is below a predetermined threshold, or if the SOC of the high-voltage battery 90 is above a predetermined value, the first motor-generator 11 and the like are powered (assisted) or the powering (assistance) amount is increased. Therefore, by lowering the SOC of the high-voltage battery 90 in advance, it is possible to avoid a situation in which the SOC of the high-voltage battery 90 reaches its upper limit during the processing of blow-by gas and the regenerative control associated with the processing of blow-by gas cannot be executed.

[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiments, the control device according to the present invention is applied to a series-parallel hybrid vehicle (HEV), but it can also be applied to other types of hybrid vehicles (e.g., parallel hybrid vehicles) and plug-in hybrid vehicles (PHEVs) that can be charged externally. Furthermore, while the above embodiments have two electric motors (first motor-generator 11 and second motor-generator 12), the number of electric motors is not limited to two (two motors) and may be one (one motor), or three (three motors) or more. Similarly, the configuration of the drive system, which is composed of multiple gears and shafts, is not limited to the above embodiments.

[0074] Furthermore, the system configuration of the controllers such as the HEV-CU 80 and the ECU 81, and the functional allocation of each controller are not limited to those in the above embodiment. Furthermore, in the above embodiment, the present invention has been described as being applied to an AWD vehicle (all-wheel drive vehicle), but the present invention can also be applied to, for example, a 2WD vehicle (FF vehicle or FR vehicle).

[0075] Furthermore, in the above embodiment, a turbocharger is used as the supercharger, but the supercharger is not limited to a turbocharger, and for example, a supercharger or the like may be used. [Explanation of symbols]

[0076] 10 Engine 11 First motor generator 12 Second motor generator 20 Flywheel damper 30 Driving force split mechanism 40 Driving reduction gear mechanism 41 Motor reduction gear 43 Drive reduction gear 50 propeller shaft 51 Transfer clutch 52 rear differential 60 front drive shaft 62 front differential 70 CAN 80 HEV-CU 81 ECU 82 PCU 90 High-voltage battery (storage battery) 91 Accelerator opening sensor 92 Throttle opening sensor 93 Outside air temperature sensor 94 Intake pressure sensor (boost pressure sensor) 95 RPM sensor 97,98 Resolver 112 Injector 113 Electronically controlled throttle valve 114 Air flow meter 117 Spark Plug 119A, 119B Air-fuel ratio sensor 133 Crank angle sensor 133a Timing rotor 134 Water temperature sensor 140 Turbocharger 141 Compressor 142 Turbine 170 Blow-by gas treatment device 171 Ventilation line (PCV line) 172 PCV valve 173 New Air Line

Claims

1. an engine having a turbocharger, and a blow-by gas treatment device including a ventilation line communicating a crankcase with a downstream side of the turbocharger and returning blow-by gas to an intake system, and a fresh air line communicating an upstream side of the turbocharger with the crankcase and introducing fresh air, for introducing the blow-by gas into the intake system and burning it; an electric motor connected to an output shaft of the engine so as to be able to transmit torque; a control unit that controls the driving of the engine and the electric motor, wherein the control unit causes the electric motor to regenerate power without reducing the output torque of the engine when at least one of the following occurs: the boost pressure falls to a predetermined threshold value or less when the outside air temperature is below a predetermined temperature and the boost pressure is positive; and the accelerator opening is reduced.

2. 2. The control device for a hybrid vehicle according to claim 1, wherein the control unit further controls the electric motor to regenerate power when a charge rate of a storage battery that supplies power to the electric motor is equal to or lower than a predetermined threshold value.

3. 3. The control device for a hybrid vehicle according to claim 1, wherein the control unit sets a target regeneration amount of the electric motor based on a boost pressure and a rate of change of an accelerator opening.

4. 4. The control device for a hybrid vehicle according to claim 1, wherein the control unit stops regeneration of the electric motor in at least one of the following cases during regeneration of the electric motor: when the boost pressure becomes equal to or higher than a first predetermined pressure; when the boost pressure becomes equal to or lower than a second predetermined pressure; when the accelerator opening degree becomes equal to or higher than a first predetermined value; and when the accelerator opening degree becomes equal to or lower than a second predetermined value.

5. 5. The control device for a hybrid vehicle according to claim 1, wherein the control unit powers the electric motor or increases the amount of powering when, in a state where the outside air temperature is equal to or lower than a predetermined temperature and the boost pressure is positive, the boost pressure is equal to or lower than a predetermined threshold and the accelerator opening degree increases, or when the charging rate of a storage battery that supplies power to the electric motor is equal to or higher than a predetermined value.

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