JP2018140719A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote warming-up of an engine during deceleration or stop of a hybrid vehicle while suppressing fuel consumption for the warming-up.SOLUTION: A hybrid vehicle includes an engine, a motor and a battery. In a state prior to warming up where a temperature of an intake wall surface of the engine is less than a dew point and on the condition that a charging state of the battery is a predetermined charging determination value or more, the control device performs the following control. That is, during deceleration of the hybrid vehicle, the control device causes a clutch between the motor and the engine to become an engagement state so as to revolve the engine without driving the engine. During stop of the hybrid vehicle, the control device causes the clutch between the motor and the engine to become an engagement state and causes a clutch between the motor and a transmission to become a disengagement state, so as to revolve the engine by rotating the motor without driving the engine.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a control device for a hybrid vehicle.

  For example, Patent Document 1 discloses control during warm-up of a hybrid vehicle. In the control of Patent Document 1, automatic stop control is performed to stop the engine when a predetermined stop condition is satisfied, such as SOC (State of Charge) that is a state of charge of the battery of the hybrid vehicle being within a predetermined range. Then, EV traveling that travels only by the motor is executed.

  Here, when the engine is cold-started, condensed water may be generated due to the exhaust gas being cooled by the EGR device. If the engine is automatically stopped in a state where condensed water is generated and the engine is stopped, the condensed water may be retained. On the other hand, in the control of Patent Document 1, in order to prevent the condensate from staying, if the wall temperature of the EGR device is not equal to or higher than the dew point, the engine is automatically stopped even if the SOC is within a predetermined range. Prohibit control. In other words, the engine warm-up is prioritized by prohibiting the automatic engine stop control and driving the engine until the EGR device is heated to evaporate the condensed water generated. .

JP 2010-121574 A JP 2011-032890 A JP-A-2015-155276 JP 2006-075259 A JP 2013-127224 A JP 2004-060449 A JP 2011-247176 A JP 2010-274762 A

  Even when the vehicle is decelerating or while the vehicle is stopped, it is possible to prioritize engine warm-up by driving the engine as in Patent Document 1. However, from the viewpoint of reducing fuel consumption, it is not preferable that fuel is consumed for warming up the engine.

  In order to solve the above-mentioned problems, the present invention has been improved so as to enable engine warm-up while the hybrid vehicle is decelerated or stopped while suppressing fuel consumption for engine warm-up. A control device for a hybrid vehicle is provided.

  In order to achieve the above object, in the hybrid vehicle control device of the present invention, the hybrid vehicle includes an engine and a motor as a power source of the vehicle, and a battery that exchanges electric energy with the motor.

  Furthermore, the hybrid vehicle control device is in a state before the warm-up when the hybrid vehicle decelerates, the temperature of the intake air wall of the engine is lower than the dew point, and the charge state of the battery is equal to or higher than a predetermined charge determination value. In some cases, the clutch between the motor and the engine is engaged, and the engine is rotated without driving the engine.

  Alternatively, the control device for the hybrid vehicle is in a state before warming up when the hybrid vehicle is stopped, the temperature of the intake wall surface of the engine is lower than the dew point, and the charge state of the battery is equal to or higher than a predetermined charge determination value. In some cases, the clutch between the motor and the engine is connected, and the clutch between the motor and the transmission is disconnected, and the engine is rotated by the rotation of the motor without driving the engine.

  According to the hybrid vehicle control device of the present invention, when the hybrid vehicle is decelerated or stopped, the engine is rotated without driving the engine when the engine is in a state before the warm-up of the engine is completed. Therefore, engine warm-up can be promoted by frictional heat due to engine rotation while suppressing fuel consumption.

It is a figure which shows typically the structure of the engine of Embodiment 1. FIG. It is a figure which shows typically the structure of HP-EGR. It is a figure which shows typically the structure of the diesel hybrid vehicle of Embodiment 1. FIG. It is a figure which shows the control state at the time of the deceleration after completion of warming-up of the engine of Embodiment 1, and the control state at the time of deceleration before completion of warming-up of an engine. It is a figure for demonstrating the relationship between outside temperature and the dew point temperature at the time of humidity 100%. 3 is a timing chart for illustrating control at the time of deceleration before completion of warm-up of the engine according to the first embodiment. 3 is a flowchart for illustrating a control routine executed by the control device in the first embodiment. It is a figure which shows the control state at the time of the vehicle stop before completion of warming-up of the engine of Embodiment 2, and the control state at the time of vehicle stop after completion of engine warm-up. 6 is a timing chart for illustrating control when the vehicle is stopped before completion of warming up of the engine according to the second embodiment. 10 is a flowchart for illustrating a control routine executed by the control device in the second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 1 is a diagram schematically showing the configuration of the engine of the first embodiment. The engine 2 in FIG. 1 is a diesel engine having a plurality of cylinders. There is no limitation on the number and arrangement of the cylinders of the engine 2. The engine 2 is mounted on a hybrid vehicle and used as a power source.

  An intake port and an exhaust port communicate with the combustion chamber of each cylinder. The intake port communicates with an intake passage 10 including the intake manifold 4. In the intake passage 10, an air cleaner 12, a warmer 14, an electromagnetic valve 16, a compressor 20 of a supercharger 18, an LT radiator 22, and a throttle valve 24 are arranged in this order from the upstream side of intake air. On the other hand, the exhaust port communicates with an exhaust passage 30 including the exhaust manifold 6. In the exhaust passage 30, a turbine 32, an NSR catalyst 34, and a DPF / SCR / SCRF catalyst 36 of the supercharger 18 are disposed in order from the upstream side of the exhaust.

  The EGR (Exhaust Gas Recirculation) system of the engine 2 includes a high pressure EGR device (hereinafter also referred to as “HP-EGR”) 40 and a low pressure EGR device (hereinafter also referred to as “LP-EGR”) 60.

  FIG. 2 is a diagram schematically showing the configuration of the HP-EGR 40. As shown in FIG. 2, the HP-EGR 40 includes a high-pressure side EGR passage (hereinafter, “HP-EGR passage”) 42. One end of the HP-EGR passage 42 is connected to a portion of the exhaust passage 30 upstream of the turbine 32, and the other end is connected to a portion of the intake passage 10 downstream of the throttle valve 24. The HP-EGR passage 42 includes an EGR valve 44 for opening and closing the passage 42, an HP-EGR cooler 46 for cooling EGR gas, a bypass passage 48 for bypassing the HP-EGR cooler 46, and an HP-EGR cooler. A bypass valve 50 installed at the outlet of 46 is provided.

  As shown in FIG. 1, the LP-EGR 60 includes a low-pressure side EGR passage (hereinafter also referred to as “LP-EGR passage”) 62. One end of the LP-EGR passage 62 is connected to a portion of the exhaust passage 30 downstream from the DPF / SCR / SCRF catalyst 36, and the other end is connected between the warmer 14 and the compressor 20 of the intake passage 10. Yes. An LP-EGR cooler 64 for cooling the EGR gas is installed in the middle of the LP-EGR passage 62.

  FIG. 3 is a diagram schematically showing the configuration of the diesel hybrid vehicle of the first embodiment. The hybrid vehicle in FIG. 3 includes the engine 2 in FIG. 1 and a motor generator (hereinafter also referred to as “MG”) 70 as power sources. The MG 70 has both a function as an electric motor and a function as a regenerative generator. Although not shown, a battery is connected to the MG 70. Electric power obtained by regeneration of MG 70 is stored in the battery, and electric power for driving MG 70 is supplied from the battery.

  The engine 2 and the motor generator 70 are connected via a clutch 72 that interrupts power transmission. The output shaft of the engine 2 is connected to a transmission (hereinafter also referred to as “T / M”) 76 via a clutch 74, and the power of the output shaft of the T / M 76 is transmitted to wheels via a differential gear or the like. However, the connection structure with the engine 2, the motor generator 70, and TM76 is not restricted to the example shown in FIG.

  Various sensors and actuators provided in the vehicle according to the first embodiment are electrically connected to the control device. The control device is an ECU (Electronic Control Unit). The control device controls the entire system of the vehicle, and is configured mainly by a computer including a CPU, a ROM, and a RAM. The ROM stores various control routines including a control routine when the vehicle is decelerated or stopped, which will be described later. The control device controls the vehicle by operating each actuator according to each control routine based on signals from each sensor.

  In this hybrid vehicle, “HV traveling” is performed in which the engine 2 is driven and the vehicle is driven by the driving force of the engine 2 in a high load region. In the low load region, the engine 2 is stopped and the vehicle is switched to “EV traveling” by the driving force of the MG 70. Therefore, since the opportunity for the engine 2 to be stopped increases, the warm-up of the engine 2 (that is, the temperature rise of the engine water temperature, wall temperature, and catalyst bed temperature) may be delayed.

  On the other hand, in the case of a high load operation region that deviates from the EV travel region, it is necessary to suppress exhaust gas by introducing a large amount of EGR in order to suppress NOx emission. However, if a high load request is issued and EGR introduction is executed in a state where the engine 2 has not been warmed up, condensed water may be generated. Condensed water is generated particularly around the water-cooled I / C, in the HP-EGR passage 42 and the HP-EGR cooler 46, the junction of the LP-EGR passage 62 and the intake passage 10, and the LP-EGR cooler 64. It's easy to do.

  In contrast, in the first embodiment, control for promoting warm-up of the engine 2 is executed during deceleration of the vehicle. FIG. 4 is a diagram illustrating a control state during deceleration after the completion of warming-up and a control state during deceleration before the completion of warming-up according to the present embodiment. As shown in FIG. 4A, when the engine 2 has been warmed up, the engine 2 and the MG 70 are separated by the clutch 72 in order to ensure a high regeneration amount of the MG 70 at the time of deceleration. The regenerative energy of MG 70 is recovered.

  On the other hand, at the time of deceleration before the completion of warm-up, on the condition that the battery is sufficiently charged, the clutch 72 is connected as shown in FIG. As a result, the vehicle and the engine 2 are connected to each other, and the engine 2 rotates even during deceleration, and the temperature rise of the engine 2 is promoted by frictional heat. Thereby, generation | occurrence | production of condensed water can be suppressed.

  By the way, in the present embodiment, whether or not the engine 2 has been warmed up and no condensed water is generated is determined based on whether or not the engine water temperature has reached a predetermined warm-up determination temperature. . Here, the predetermined warm-up determination temperature is set according to the outside air temperature. FIG. 5 is a diagram for explaining the relationship between the outside air temperature and the dew point temperature at a humidity of 100%. As shown in FIG. 5, the dew point temperature varies depending on the outside air temperature. That is, the temperature at which condensed water is generated inside the engine 2 changes according to the outside air temperature. Therefore, in the present embodiment, the relationship between the outside air temperature and the warm-up determination temperature with respect to the engine water temperature is obtained in advance and stored in the control device so that the warm-up determination temperature corresponding to the outside air temperature is set.

  In this embodiment, the engine water temperature is used as a parameter for determining whether or not the engine has been warmed up. However, the determination of whether or not the engine 2 has been warmed up is not limited to this. Further, the warm-up in the present embodiment is not limited to the complete warm-up of the engine 2, and it is sufficient that the condensed water does not stay, for example, the temperature of the intake wall surface exceeds the dew point. Therefore, in order to determine such warm-up, oil temperature, engine wall temperature, etc. may be used as parameters instead of engine water temperature. Also, the temperature of each part of the engine, such as water temperature, oil temperature, wall temperature, etc., is detected, and the warm-up is completed depending on whether each detected temperature exceeds the maximum dew point temperature calculated based on the outside air temperature. Can also be determined. At this time, the maximum dew point temperature can be set for each part of the engine.

  FIG. 6 is a timing chart for explaining the control at the time of deceleration before the warm-up is completed. In FIG. 6, for the sake of simplicity of explanation, the accelerator opening is represented by complete ON / OFF, that is, only fully open / closed.

  In the example of the control in FIG. 6, the engine water temperature is lower than the warm-up determination temperature, that is, before the warm-up of the engine 2 is completed, from the start time t0 to the time t8.

  The SOC is higher than the charge determination value before the warm-up is completed and during the time t2 to t3 when the accelerator opening is zero and the vehicle is decelerating and during the time t4 to t5. Here, the charge determination value is a threshold value for determining that the battery is sufficiently charged. Therefore, the engine 2 and the MG 70 are connected by the clutch 72 (that is, the ON state). As a result, during the time t2 to t3 and between the time t4 and t5, the engine 2 rotates, and warming up of the engine 2 is promoted by the frictional heat of rotation.

  On the other hand, the SOC is lower than the charge determination value during the time t6 to t7 when the vehicle is decelerating. Accordingly, the coupling of the clutch 72 is turned off, and the regenerative energy is recovered by the MG 70. That is, priority is given to battery charging.

  Thereafter, at time t8 when the engine water temperature exceeds the warm-up determination temperature, the engine 72 and the MG 70 are disconnected by the clutch 72 during deceleration (that is, the clutch 72 is turned off). Thereby, after the warm-up is completed, the charging of the battery is prioritized.

  FIG. 7 is a flowchart for illustrating a control routine executed by the control device in the present embodiment. In the routine shown in FIG. 7, first, the outside air temperature is acquired in step S102. Next, the process proceeds to step S104, and the warm-up determination temperature is calculated according to the outside air temperature acquired in step S102. Next, in step S106, the engine water temperature is acquired.

  Next, the process proceeds to step S108, and it is determined whether or not the engine coolant temperature acquired in step S106 is equal to or higher than the warm-up determination temperature calculated in step S104. If the determination result in step S108 is YES, that is, if it is determined that the engine water temperature is equal to or higher than the warm-up determination temperature, it is determined that the engine 2 has been warmed up. Ends.

  On the other hand, if the determination result in step S108 is NO, that is, if it is determined that the engine water temperature is lower than the warm-up determination temperature, then in step S110, it is determined whether or not the present time is an accelerator-off deceleration time. Determined. If the determination result of step S110 is NO, that is, if it is determined that the vehicle is not decelerating, the current process ends.

  On the other hand, if the determination result in step S110 is YES, that is, if it is determined that the current time is deceleration when the accelerator is OFF, then in step S112, whether or not the SOC of the battery is greater than or equal to the charge determination value. Determined.

  If the determination result in step S112 is YES, that is, if it is determined that the SOC of the battery is greater than or equal to the charge determination value, the process proceeds to step S114, and the clutch 72 is maintained in the coupled state. As a result, the engine 2 rotates even during deceleration, and the warm-up of each part of the engine 2 is promoted by friction.

  On the other hand, when the determination result of step S112 is NO, that is, when it is determined that the SOC of the battery is smaller than the charge determination value, the process proceeds to step S116, and the clutch 72 is disconnected. Thereby, the charging of the battery is prioritized, and the regenerative energy of the MG 70 is recovered by the battery. After the process of step S114 or S116, the current process ends.

  As described above, in the present embodiment, the engine 2 and the MG 70 are connected and rotated on the condition that the battery is sufficiently charged before the engine 2 is warmed up and decelerated. Thus, warm-up of the engine 2 can be promoted by frictional heat even during deceleration. Therefore, the stay of condensed water can be suppressed.

Embodiment 2. FIG.
The system of the second embodiment has the same configuration as the system of the first embodiment. The second embodiment executes control for promoting warm-up of the engine 2 before the warm-up of the engine 2 is completed and when the vehicle is stopped. FIG. 8 is a diagram showing a control state when the vehicle is stopped before completion of warming up of the engine and a control state when the vehicle is stopped after completion of warming up of the engine.

  As shown in FIG. 8A, MG 70 and engine 2 are connected by clutch 72 on the condition that the SOC of the battery is sufficient before the warm-up of engine 2 is completed and when the vehicle is stopped. On the other hand, the T / M 76 is disconnected by the clutch 74, and the vehicle and the engine 2 are disconnected. Further, the MG 70 is driven to rotate when the vehicle is stopped. Thereby, the engine 2 is rotated, and the warm-up of the engine 2 is promoted by the frictional heat. On the other hand, after the engine 2 is warmed up, while the vehicle is stopped, as shown in FIG. 8B, the clutch 72 and the clutch 74 are maintained in the connected state, and the engine 2 and the MG 70 are stopped.

  FIG. 9 is a timing chart for explaining the control of the second embodiment. In the example shown in FIG. 9, the engine water temperature is lower than the warm-up determination temperature from the start time t0 to time t7, that is, the engine 2 is in a state before the warm-up is completed.

  The battery SOC is higher than the charge determination value during the time t1 to t2 when the vehicle is stopped and during the time t3 to t4. Therefore, T / M 76 is N-controlled between time t1 and t2 and between time t3 and t4, that is, the vehicle and engine 2 are disconnected. During this time, the MG 70 and the engine 2 are connected by the clutch 72, and the engine 2 is rotated by the rotation of the MG 70. Thereby, warm-up of the engine 2 is promoted.

  In addition, although the vehicle is stopped before the warm-up is completed, the SOC of the battery is below the charge determination value during the time t5 to t6. Therefore, motor driving by MG 70 is not executed. Here, the T / M 76 is connected by the clutch 74, and the engine 2 and the MG 70 are stopped.

  FIG. 10 is a flowchart for illustrating a control routine executed by the control device in the second embodiment. The routine of FIG. 10 is a routine that is executed in place of the routine of FIG. 7, and is different from the routine of FIG. 7 except that the processing of steps S204 to S212 is performed instead of the processing of steps S108 to S116 of FIG. 7. Are the same.

  Specifically, after the process of step S106, the oil temperature of T / M 76 is acquired in step S202. Next, in step S204, it is determined whether the engine water temperature is equal to or higher than the warm-up determination temperature and the T / M 76 oil temperature is equal to or higher than a predetermined temperature.

  If the determination result in step S204 is YES, that is, if it is determined that the engine water temperature is equal to or higher than the warm-up determination temperature and the T / M 76 oil temperature is equal to or higher than the predetermined temperature, the current process ends. .

  On the other hand, when the determination result of step S204 is NO, that is, when it is determined that the engine water temperature is lower than the warm-up determination temperature or the T / M 76 oil temperature is lower than the predetermined temperature, Proceeding to step S206, it is determined whether or not the vehicle is currently stopped. If the determination result of step S206 is NO, that is, if it is determined that the vehicle is not stopped, the current process ends.

  On the other hand, if the determination result in step S206 is YES, that is, if it is determined that the vehicle is stopped, then in step S208, it is determined whether or not the SOC of the battery is greater than or equal to the charge determination value. . If the determination result in step S208 is NO, that is, if it is determined that the SOC of the battery is lower than the charge determination value, the current process ends.

  On the other hand, if the determination result in step S208 is YES, that is, if it is determined that the SOC of the battery is equal to or greater than the charge determination value, then T / M 76 is N-controlled in step S210. That is, the clutch 74 disconnects the vehicle from the T / M 76.

  Next, in step S212, the MG 70 is rotated, and as a result, the engine 2 and the T / M 76 are rotated. Thereby, warm-up of the engine 2 is promoted while the vehicle is stopped. Thereafter, the current process ends.

  As described above, according to the present embodiment, warming up of engine 2 can be promoted by rotating engine 2 by MG 70 while the vehicle is stopped before warming up of engine 2 is completed. Thereby, the engine 2 can be warmed up while suppressing fuel consumption, and the generation of condensed water can be suppressed.

  In the above embodiment, when referring to the number of each element, quantity, quantity, range, etc., the reference is made unless otherwise specified or the number is clearly specified in principle. The invention is not limited to the numbers. Further, the structure and the like described in this embodiment are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

2 engine 40 HP-EGR
60 LP-EGR
70 Motor generator 72 Clutch 74 Clutch 76 T / M

Claims (2)

An engine and a motor as a power source of the vehicle,
A battery for transferring electrical energy to and from the motor;
A control device for a hybrid vehicle comprising:
When the hybrid vehicle decelerates, and
The temperature of the intake wall of the engine is less than the dew point before warming up, and
When the state of charge of the battery is greater than or equal to a predetermined charge determination value,
A control apparatus for a hybrid vehicle, wherein a clutch between the motor and the engine is in a connected state, and the engine is rotated without driving the engine. An engine and a motor as a power source of the vehicle,
A battery for transferring electrical energy to and from the motor;
A control device for a hybrid vehicle comprising:
When the hybrid vehicle is stopped; and
The temperature of the intake wall of the engine is less than the dew point before warming up, and
When the state of charge of the battery is greater than or equal to a predetermined charge determination value,
The clutch between the motor and the engine is connected, and the clutch between the motor and transmission is disconnected, and the engine is rotated by rotation of the motor without driving the engine. An engine control device.

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