JP6516404B2 - Hybrid vehicle travel control device - Google Patents

Description

  The present invention relates to a travel control device of a hybrid vehicle including an engine and a motor as travel drive sources.

  In recent hybrid vehicles, road environment information (hereinafter referred to as route information) in a traveling route ahead of the vehicle is acquired using a navigation system etc., and the fuel consumption rate of the engine is minimized using the route information. As such, development of technology for controlling an engine and a motor is in progress.

  For example, in Patent Document 1, using the route information, the predicted value of the operating point of the engine is calculated from the predicted vehicle speed value and the braking / driving force predicted value of the vehicle along the traveling route, The engine is generating electricity by rotating the motor. As a result, the operating point is changed so that the fuel consumption rate of the engine becomes a better value, and the fuel consumption rate at that point is improved, and thus the fuel consumption in the section is minimized.

JP 2000-324609 A

  In the technology described in Patent Document 1, the engine load is increased to a region with a high fuel consumption rate by generating electricity by rotating the motor with the engine in a low load section where the fuel consumption rate of the engine is low such as a gentle downhill. Although the fuel consumption rate is being improved, the fuel consumption of the engine will increase as it generates electricity.

  Since a motor, an inverter, a battery, and the like always have a loss due to charge and discharge, it is impossible to use all the electric power (energy) obtained by the power generation by the engine as the power of the motor. In other words, simply using a motor as an assist for the engine can not recover all the energy of the fuel used for power generation by the engine, and overall it may cause the fuel consumption to increase. is there.

  The present invention has been made to solve such a problem, and the object of the present invention is to efficiently use power obtained by rotating a motor by an engine to generate power in a hybrid vehicle. An object of the present invention is to provide a travel control device for a hybrid vehicle that can reduce fuel consumption as a whole.

In order to achieve the above-mentioned object, in the first invention, an engine and a motor as a drive source for traveling a vehicle, a battery for supplying electric power to the motor, and route information for acquiring route information in front of the vehicle Low load section which predicts the driving condition of the vehicle at each point based on the acquisition unit and the route information acquired by the route information acquisition unit, and detects a low load section where the required torque is equal to or less than a predetermined low load determination threshold A detection unit, an average torque calculation unit that calculates an average required torque that averages the required torque in the low load section, and the motor that generates the average required torque by the engine in the low load section; The average request torque is generated by the motor using an engine power generation traveling mode in which power generation is performed by rotating and power generated in the engine power generation traveling mode. A drive mode setting unit for setting an execution range of each of the motor drive modes, and an engine power generation drive mode and a motor drive mode set by the drive mode setting unit when the vehicle travels in the low load section And a low load travel control unit configured to control the engine and the motor according to an execution range , wherein the travel mode setting unit controls the power generated by the engine power generation travel mode at the low load section end point according to the motor travel mode. The low load travel control unit sets a target charge amount of the used up amount, and the low load travel control unit sets the target charge amount when the charge amount of the battery reaches the target charge amount by the electric power generated by the engine power generation travel mode Switch to motor drive mode .

  In a second invention, in the first invention, the driving mode setting unit is configured to use the electric power generated in the engine power generation traveling mode at the end point of the low load section in the motor traveling mode. An execution range of the power generation travel mode and the motor travel mode is set.

In the third invention, in the first or second aspect of the invention, based on the route information acquired by the pre-Symbol path information acquiring unit, the charge amount prediction unit for predicting the amount of charge of the battery in the front of the vehicle on the route And the low load travel control unit sets the travel mode setting unit when the charge amount of the battery at the low load section start point predicted by the charge amount prediction unit is less than or equal to a predetermined amount. The engine and the motor are controlled in accordance with the engine power generation travel mode and the execution range of the motor travel mode set by the controller.

In a fourth invention according to any one of the first to third inventions, the average torque calculation unit determines whether the calculated average required torque is lower than a fuel efficiency determination threshold lower than the low load determination threshold. If the average required torque is lower than the fuel efficiency determination threshold, the low load travel control unit determines the engine power generation travel mode and the motor travel mode execution range set by the travel mode setting unit. Control the engine and the motor.

In a fifth invention according to any one of the first to fourth inventions, the low load travel control unit is set by the travel mode setting unit when the vehicle travels in the low load section. The engine and the motor are controlled to maintain the target vehicle speed set by the driver according to the execution range of the engine power generation travel mode and the motor travel mode.
In a sixth aspect of the invention according to any one of the first to fifth aspects of the invention, in the engine power generation traveling mode, power is generated at an operating point of the engine where fuel efficiency is optimal and motor efficiency of the motor is the best.

  According to the present invention using the above-described means, in a hybrid vehicle, it is possible to reduce the fuel consumption as a whole by efficiently using the power obtained by rotating the motor by the engine to generate power.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the hybrid vehicle provided with the traveling control apparatus in one Embodiment of this invention. It is a flowchart which shows the traveling mode setting routine in low load traveling control. It is a flow chart which shows run mode execution routine in low load run control. It is an explanatory view showing transition of various operation states when low load traveling control is performed.

FIG. 1 is an overall configuration diagram showing a hybrid vehicle equipped with the travel control device of the present embodiment.
The hybrid vehicle 1 is configured as a so-called parallel hybrid truck, and may be referred to as a vehicle in the following description.

  The vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source, and a motor 3 which can also operate as a generator, for example, a permanent magnet synchronous motor. The clutch 4 is connected to the output shaft of the engine 2, and the input side of the automatic transmission 5 is connected to the clutch 4 via the rotation shaft of the motor 3. A differential gear 7 is connected to the output side of the automatic transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential gear 7 via a drive shaft 8.

  The automatic transmission 5 is an automatic transmission / disconnection operation of the clutch 4 based on a general manual transmission and a shift operation of shift stages. In this embodiment, there are 6 forward speed and 1 reverse speed stages. doing. Naturally, the configuration of the transmission 5 is not limited to this, and can be arbitrarily changed. For example, it may be embodied as a manual transmission or a so-called dual clutch automatic transmission provided with a power transmission system of two systems. It may be embodied as a machine.

  A battery 11 is connected to the motor 3 via an inverter 10. The direct current power stored in the battery 11 is converted into alternating current power by the inverter 10 and supplied to the motor 3, and the driving force generated by the motor 3 is transmitted to the driving wheels 9 after being shifted by the automatic transmission 5. Run (this is called power running). Further, for example, when the vehicle 1 is decelerating or traveling on a downhill road, the motor 3 operates as a generator due to reverse driving from the drive wheels 9 side. The negative side driving force generated by the motor 3 is transmitted to the drive wheel 9 as a braking force, and the AC power generated by the motor 3 is converted to DC power by the inverter 10 to charge the battery 11 (this is It is called regenerative operation). Furthermore, it is also possible to rotate the motor 3 by the driving force generated by the engine 2 to generate power and charge the battery 11 (this is called engine power generation).

  The driving force generated by such a motor 3 is transmitted to the drive wheel 9 regardless of the engagement / disengagement state of the clutch 4 while the driving force generated by the engine 2 is a drive wheel only when the clutch 4 is engaged. It is transmitted to the 9 side. Therefore, when the clutch 4 is disengaged, the positive or negative driving force generated by the motor 3 as described above is transmitted to the drive wheel 9 to drive the vehicle 1. Further, when the clutch 4 is connected, the driving force of the engine 2 and the motor 3 is transmitted to the driving wheel 9 side, or only the driving force of the engine 2 is transmitted to the driving wheel side, whereby the vehicle 1 travels.

  The vehicle ECU 13 is a control circuit for integrally controlling the entire vehicle. For this purpose, the vehicle ECU 13 includes an accelerator sensor 15 for detecting the amount of operation of the accelerator pedal 14, a brake switch 17 for detecting the stepping operation of the brake pedal 16, a vehicle speed sensor 18 for detecting the speed of the vehicle 1, and the rotational speed of the engine 2. Various sensors and switches such as an engine rotational speed sensor 19 to be detected and a motor rotational speed sensor 20 to detect the rotational speed of the motor 3 are connected.

  Although not shown, an actuator for connecting and disconnecting the clutch 4 and an actuator for shifting the automatic transmission 5 are connected to the vehicle ECU 13, and the engine ECU 22 for engine control and the inverter ECU 23 for inverter control. , And a battery ECU 24 that manages the battery 11 are connected.

  The vehicle ECU 13 calculates a required torque required for causing the vehicle 1 to travel based on an accelerator operation amount by the driver, etc., and based on the required torque, the SOC of the battery 11 (state of charge: State Of Charge), etc. Select the driving mode. In this embodiment, an engine travel mode in which travel is performed using only the driving force of the engine 2, a motor travel mode in which travel is performed using only the driving force of the motor 3, and driving forces of the engine 2 and the motor 3 are used as travel modes. The engine power generation travel mode is set in which the motor 3 is rotated using the driving power of the engine 2 to generate electric power while traveling using the hybrid driving mode in which the vehicle travels and the driving power of the engine 2 The vehicle ECU 13 selects one of the travel modes.

  The vehicle ECU 13 converts the required torque into a torque command value to be output by the engine 2 or the motor 3 based on the selected travel mode. For example, in the hybrid travel mode, after the required torque is distributed to the engine 2 side and the motor 3 side, torque command values of the engine 2 and the motor 3 are calculated based on the gear position at that time. Further, in the engine travel mode, the required torque is converted into a torque command value to the engine 2 based on the shift speed, and in the motor travel mode, the required torque is converted to a torque command value to the motor 3 based on the shift speed. Further, in the engine power generation traveling mode, a value obtained by combining the required torque and the torque required for the power generation by the motor 3 is calculated as a torque command value of the engine 2.

  Then, in order to execute the selected travel mode, the vehicle ECU 13 disconnects the clutch 4 in the motor travel mode and connects the clutch 4 in the engine travel mode, the hybrid travel mode and the engine power generation travel mode, and then the engine ECU 22 and the inverter. The torque command value is appropriately output to the ECU 23. Further, while the vehicle 1 is traveling, the vehicle ECU 13 calculates a target shift speed from a shift map (not shown) based on the accelerator operation amount, the vehicle speed, etc., and achieves the target shift speed. Execute shift gear switching operation.

  On the other hand, engine ECU 22 executes injection amount control and injection timing control so as to achieve a torque command value based on the travel mode selected in vehicle ECU 13. For example, in the engine travel mode, the hybrid travel mode, and the engine power generation travel mode, driving force is generated in the engine 2 for the torque command value on the positive side, and engine braking is generated for the torque command value on the negative side. Further, in the case of the motor travel mode, the engine 2 is stopped or held in an idle operation state by stopping fuel injection.

  Further, inverter ECU 23 controls driving of motor 3 via inverter 10 so as to achieve a torque command value based on the travel mode selected in vehicle ECU 13. For example, in the motor travel mode and the hybrid travel mode, the power running control of the motor 3 is performed with respect to the torque command value on the positive side to generate the driving force on the positive side. The motor 3 is regeneratively controlled for the torque command value on the negative side. And generate a negative driving force. Further, in the case of the engine travel mode, the driving force of the motor 3 is controlled to zero. Furthermore, in the case of the engine power generation traveling mode, the driving force of the engine 2 is received to generate power.

  Further, the battery ECU 24 detects the temperature of the battery 11, the voltage of the battery 11, the current flowing between the inverter 10 and the battery 11, etc., and calculates the SOC (charge amount) of the battery 11 from these detection results. The SOC is output to the vehicle ECU 13 together with the detection result.

  On the other hand, the vehicle ECU 13 can execute auto cruise control for controlling the engine 2 and the motor 3 so as to maintain the target vehicle speed VSt set by the driver. When the driver operates the execution switch of auto cruise control (not shown) to set the target vehicle speed VSt, the vehicle ECU 13 controls the torque of the engine 2 and the motor 3 to set the vehicle speed VS to the target vehicle speed VSt and accelerates. Do the deceleration.

  In the auto cruise control according to the present embodiment, the driving mode is selected after predicting the driving state of the vehicle 1 at each point based on the road environment information (route information) in the traveling route ahead of the vehicle. Therefore, the navigation device 31 is connected to the vehicle ECU 13 as shown in FIG. 1 in order to detect the route information ahead of the vehicle.

  The navigation device 31 uses the map data stored in its own storage area, GPS information received via an antenna, VICS (registered trademark) information, etc., while the vehicle 1 is traveling. Identify the road surface gradient and curves etc. ahead of the vehicle.

  The vehicle ECU 13 acquires, for example, road surface gradient information from the navigation device 31 in the auto cruise control, and classifies a route ahead of the vehicle based on the road surface gradient information. Then, for example, in a section of a downhill road, the motor travel mode is set to perform regenerative operation. Further, in the section of the uphill or flat road, if the SOC predicted in the section is relatively large, the motor travel mode is set. If the SOC is relatively small, the engine travel mode is set.

  Particularly, in the present embodiment, there is a low load section such as a gentle downhill road where the fuel efficiency of the engine 2 is deteriorated on the route ahead of the vehicle, and the SOC in the low load section is 0 or a very small amount. In addition, low load traveling control combining the engine power generation traveling mode and the motor traveling mode is executed.

  Specifically, as shown in FIG. 1, the vehicle ECU 13 includes a low load traveling control unit 40 for executing low load traveling control, and the low load traveling control unit 40 includes a route information acquisition unit 41 and a low information. The load section detection unit 42, the SOC prediction unit 43, the average torque calculation unit 44, and the traveling mode setting unit 45 are included.

  The low load travel control unit 40 causes the route information acquisition unit 41 to acquire route information ahead of the vehicle detected by the navigation device 31. Then, the route information acquisition unit 41 calculates the required torque DT required to maintain the target vehicle speed VSt based on the road slope at each point ahead of the host vehicle, the weight of the host vehicle, and the like.

  The low load section detection unit 42 calculates the required torque and the like required to maintain the target vehicle speed VSt at each point from the weight information of the vehicle and the road surface gradient information included in the acquired route information, and the request A low load section in which the torque is equal to or less than a predetermined low load determination threshold DTa is detected. The low load section detection unit 42 also determines whether the low load travel time ΔT taken when the detected low load section is traveled at the target vehicle speed VSt is larger than a predetermined time Ta set in advance. The predetermined time Ta is a time which is arbitrarily set so that disconnection and disconnection of the clutch 4 are not frequently performed in consideration of disconnection and disconnection time of the clutch 4 accompanying switching from the engine power generation travel mode to the motor travel mode.

  The SOC prediction unit 43 acquires SOC information of the battery 11 from the battery ECU 24, and predicts the SOC at each point from the route information, the predicted operation state, and the like. The SOC prediction unit 43 also determines whether the SOC at the low load section start point is equal to or less than a predetermined value Sa. The predetermined value Sa is set to an allowable lower limit value of the SOC that requires engine power generation.

  The average torque calculation unit 44 calculates an average required torque DTave obtained by averaging the required torque DT in the low load section. Further, the average torque calculation unit 44 determines whether the calculated average required torque DTave is equal to or less than a predetermined fuel consumption determination threshold DTb. The fuel efficiency determination threshold value DTb is an upper limit load at which the fuel efficiency improvement effect can be obtained by low load traveling control in advance by experiment or the like, and is a value lower than the low load determination threshold value DTa.

  The traveling mode setting unit 45 sets the ratio of the range in which the engine power generation traveling mode is executed in the low load section and the range in which the motor traveling mode is subsequently executed based on the average required torque DTave. The period during which the vehicle travels in the engine power generation traveling mode is ΔT1 of the traveling time ΔT required when traveling in the low load section at the target vehicle speed VSt, and the remaining charge amount for charging the battery 11 during the ΔT1 is The ratio .DELTA.T: T-.DELTA.T1 of the execution range of the engine power generation travel mode and the execution range of the motor travel mode is set so that the motor travel mode of the period (T-.DELTA.T1) is used up.

  Specifically, ΔT1 is obtained by the following (2) obtained from the following equation (1) in which the charge amount charged to the battery 11 in the engine power generation travel mode and the charge amount consumed from the battery 11 in the motor travel mode are equal. calculate.

ΔT1 × CPave = (ΔT−ΔT1) × MPave (1)
ΔT1 = ΔT × MPave / (CPave + MPave) (2)
Here, the average charge amount CPave per unit time charged in the battery 11 when traveling in the low power section in the engine power generation traveling mode and the average motor work MPave per unit time necessary to travel in the motor traveling mode are It can be calculated from the characteristic maps of the engine 2 and the motor 3 so as to minimize the fuel consumption.

  For example, the average charge amount CPave is equal to or greater than the average required torque DTave from the characteristic map of the engine 2, and the operation of the engine 2 where the motor efficiency is the best from the characteristic map of the motor 3 when the fuel efficiency is optimal and the motor 3 generates power. A point is calculated, and it is calculated as what is produced | generated by the torque for the amount exceeding average demand torque. Further, the average motor work MPave corresponds to the work required to output the average required torque DTave capable of reducing fuel consumption by motor travel according to the characteristic map of the engine 2 and the motor 3.

Further, traveling mode setting unit 44 sets a target SOC St (an amount of accumulation more than a target charging amount (= ΔT1 × CPave) in a low load section from traveling period ΔT1 of engine power generation traveling mode and average charging amount CPave. .
When the vehicle 1 travels in a low load section, the low load travel control unit 40 performs the engine power generation travel mode and the motor travel mode at the ratio set by the travel mode setting unit 45 via the engine ECU 22. The engine 2 is controlled, and the motor 3 is controlled via the inverter ECU 23.

  Here, referring to FIGS. 2 and 3, FIG. 2 shows a traveling mode setting routine for low load traveling control, and FIG. 3 shows a traveling mode execution routine for low load traveling control in a flowchart, respectively. The flow of low load travel control in the present embodiment will be described along the flowchart. The low load travel control is performed during execution of the auto cruise control.

First, as shown in FIG. 2, the low load travel control unit 40 acquires the route information ahead of the vehicle detected by the navigation device 31 in the route information acquisition unit 41 as Step S1.
Then, in step S2, the low load interval detection unit 42 calculates the required torque DT at each point, and determines whether a low load interval in which the required torque DT is equal to or less than the low load determination threshold DTa is detected. If the determination result is false (No), that is, if there is no low load section in front of the vehicle, it is not necessary to perform the low load travel control, and the routine ends. On the other hand, when the said determination result is true (Yes), it progresses to following step S3.

  In step S3, the low load section detection unit 42 determines whether the low load travel time ΔT taken when traveling in the low load section at the target vehicle speed VSt is larger than a predetermined time Ta. The routine also ends if the determination result is false (No). On the other hand, if the determination result is true (Yes), the process proceeds to the next step S4.

  In step S4, the SOC prediction unit 43 determines whether the SOC at the low load section start point is equal to or less than a very small predetermined value Sa. If the determination result is false (No), the routine ends. On the other hand, if the determination result is true (Yes), the process proceeds to the next step S5.

In step S5, the average torque calculation unit 44 calculates an average required torque DTave obtained by averaging the required torque DT in the low load section.
Then, in the next step S6, the average torque calculation unit 44 determines whether the average required torque DTave is equal to or less than the fuel consumption determination threshold DTb. If the determination result is false (No), the routine ends. On the other hand, if the determination result is true (Yes), the process proceeds to the next step S7.

  In step S7, the travel mode setting unit 45 sets the ratio of the range in which the engine power generation travel mode is to be executed to the range in which the motor travel mode is to be executed in the low load section. Specifically, a period ΔT1 for traveling in the engine power generation traveling mode is set from the above-described equation (2), and the remaining period T−ΔT1 is set as a period for the motor traveling mode.

Then, in the next step S8, the travel mode setting unit 45 sets a target SOC St (= ΔT1 × CPave) in the low load section from the travel period ΔT1 of the engine power generation travel mode and the average charge amount CPave.
Thus, after setting the ratio of the range of the engine power generation travel mode and the range of the motor travel mode in the low load section based on the travel mode setting routine, the low load travel control unit 40 executes the travel mode shown in FIG. Run the routine

  Specifically, as shown in FIG. 3, the low load travel control unit 40 determines whether or not the vehicle 1 has reached the start point of the low load section at Step S10. If the determination result is false (No), it is not yet time to execute the low load traveling control, so the determination in step S10 is repeated. On the other hand, if the determination result is true (Yes), the process proceeds to the next step S11.

In step S11, the low load traveling control unit 40 executes the engine power generation traveling mode from the low load section start point.
Then, in step S12, the low load travel control unit 40 determines whether the SOC of the battery 11 is larger than the target SOC St. If the determination result is false (No), the determination in step S12 is repeated. On the other hand, if the determination result is true (Yes), the process proceeds to the next step S13.

In step S13, the low load traveling control unit 40 switches the traveling mode to the motor traveling mode.
Then, in step S14, the low load travel control unit 40 determines whether the vehicle 1 has reached the end point of the low load section or whether the SOC has become equal to or less than the predetermined lower limit value Sa. If the determination result is false (No), the determination in step S12 is repeated. On the other hand, if the determination result is true (Yes), the routine ends.

  Here, FIG. 4 is an explanatory view showing a transition of various operating states when the low load traveling control is executed. Specifically, the altitude and slope of the route ahead of the vehicle, the required torque, the engine torque, the motor torque, the SOC, and the fuel consumption are shown as various driving states. In addition, in FIG. 4, various driving | running states are simply shown so that it may be easy to understand the transition. Hereinafter, the operation and effects of the travel control device for a hybrid vehicle according to the present embodiment will be described based on FIG.

  First, as shown in FIG. 4, the vehicle 1 recognizes the altitude and the road surface gradient of the route ahead of the vehicle by acquiring route information ahead of the vehicle. Then, the required torque DT required to travel at the target vehicle speed VSt is calculated from the gradient at each point, and the required torque DT is within the range of the low load determination threshold DTa or less. Be done. Further, transition of the SOC is also predicted, and is equal to or less than the allowable lower limit value (predetermined value Sa) of the SOC at the s1 point which is the start point of the low load section. Furthermore, the required torque in the low load section is averaged to calculate the average required torque DTave, and in FIG. 4 the average required torque DTave is equal to or less than the fuel efficiency determination threshold DTb. Traveling control is performed.

  At point s3 in FIG. 4, the required torque DT temporarily rises and exceeds the fuel efficiency determination threshold DTb, but in the low load traveling control in this embodiment, the low load determination threshold DTa is higher than the fuel efficiency determination threshold DTb. Since it is a high value and comparing the average required torque DTave with the fuel efficiency determination threshold DTb, the s3 point can also be included in the low load section. That is, the low load section can be made long, and the range for executing the low load traveling control can be expanded.

  Further, as shown in FIG. 4, by setting the period of ΔT1 in the first half of the low load section obtained from the above equation (2) to the engine power generation traveling mode, the engine torque is increased to the required torque or more and becomes surplus. The engine torque is used for power generation by the motor 3, and the SOC is charged to the target SOC St. The remaining period ΔT-ΔT1 is set to the motor travel mode, and travel is performed only by the motor 3 so that the SOC charged to the target SOC St is used up.

  As described above, in the low load section, the fuel consumption in the low load section is achieved by operating the engine 2 with high fuel efficiency in the first half in the engine power generation traveling mode and driving the engine 2 in the idling state in the second half. It is kept to a minimum.

  In FIG. 4, engine torque and fuel consumption when traveling in the low engine speed mode in all the low load sections are shown by broken lines. Compared with the fuel consumption amount of the present embodiment shown by the solid line, in the present embodiment, the engine torque is increased by the amount of power generation by the motor 3 from the s1 point to the s2 point, and the fuel consumption amount increases However, after shifting to the motor travel mode from the s2 point, only the fuel for idling is consumed, and the increase in fuel consumption is suppressed. Then, at the s4 point at the end point of the low load section, the fuel consumption can be reduced more than in the case of traveling only in the engine travel mode.

  As described above, in the low load travel control in this embodiment, the engine 2 operates with high fuel efficiency in the first half and idles in the second half in the low load section, and the electric power generated by the engine 2 in the first half is motor driven It can be used more efficiently to reduce the overall fuel consumption.

  Furthermore, in the low load traveling control, the engine 2 and the motor 3 are controlled based on an average required torque DTave obtained by averaging the required torque in the low load section. Thus, for example, even in a low load section, if the required torque is relatively large in the first half, the amount of power generation in the engine power generation travel mode decreases, the range of the motor travel mode narrows, and the fuel efficiency improvement effect is low However, by controlling the engine and the motor based on the average required torque DTave, it is possible to prevent the imbalance between the torque in the engine power generation traveling mode and that in the motor traveling mode, and stably obtain the improvement effect of the fuel consumption. Can.

  In addition, the execution range of the engine power generation travel mode and the motor travel mode is set so that the power generated in the engine power generation travel mode is used up in the motor travel mode, and the low power section ends the power generated in the engine power generation travel mode I will not leave behind. Thereby, for example, even when there is a long downhill road immediately after the end of the low load section, etc., the SOC of the battery 11 can be charged from 0 to the upper limit by the regenerative operation of the motor 3, and the electric power generated in the engine power generation traveling mode Can be used to prevent inefficient use. That is, by exhausting the SOC in the low load section, the fuel consumption improvement effect can be reliably obtained regardless of the route state after the low load section ends.

  Further, by performing the low load traveling control only when the SOC is equal to or less than the predetermined value Sa, the motor traveling mode can be efficiently traveled in a wide range as much as possible even when the low load section can not be traveled in the motor traveling mode It can be performed. On the other hand, when the SOC of the battery 11 is sufficient before the start of the low load section, it is possible to prevent the engine power generation traveling mode from being performed in vain.

Furthermore, since switching of the traveling mode in the low load traveling control is performed when the SOC of the battery 11 reaches the target SOC St, switching control of the traveling mode can be facilitated.
And since low load traveling control in this embodiment is performed as a part of auto cruise control, the fuel consumption in auto cruise control can be reduced certainly.

This completes the description of the embodiment of the travel control device for a hybrid vehicle according to the present invention, but the embodiment is not limited to the above embodiment.
In the above embodiment, the low load traveling control is executed as a part of the auto cruise control, but the low load traveling control is not necessarily limited to that executed during the auto cruise control. For example, if it is possible to obtain route information ahead of the vehicle, estimate the required torque and vehicle speed of each point from the driving history etc, and calculate the travel time ΔT of the low load section and the low load section, only during auto cruise control Therefore, the low load traveling control according to the present invention can be applied.

  In addition to the above embodiment, when it is predicted that the SOC at the time of entering the low load section does not become the allowable lower limit value (predetermined value Sa), the SOC is used up to the allowable lower limit value before entering the low load section. Alternatively, it is possible to further predict the point at which the SOC is used up and to start low load traveling control from that point.

2 engine 3 motor 4 clutch 11 battery 13 vehicle ECU
22 engine ECU
23 Inverter ECU
31 Navigation Device 40 Low-Load Travel Control Unit 41 Route Information Acquisition Unit 42 Low-Load Section Detection Unit 43 SOC Prediction Unit (Charge Amount Prediction Unit)
44 Average torque calculation unit 45 Drive mode setting unit

Claims (6)

An engine and a motor as a drive source for traveling the vehicle;
A battery for supplying power to the motor;
A route information acquisition unit that acquires route information ahead of the vehicle;
A low load interval detection unit that predicts the driving state of the vehicle at each point based on the route information acquired by the route information acquisition unit and detects a low load interval where the required torque is equal to or less than a predetermined low load determination threshold;
An average torque calculation unit that calculates an average required torque obtained by averaging the required torques in the low load section;
In the low load section, the motor generates an average required torque by the engine and rotates the motor to generate electric power, and the motor generates electric power using the electric power generated in the engine electric power generation traveling mode. A traveling mode setting unit configured to set an execution range of each of the motor traveling modes for generating the average required torque;
A low load travel control unit configured to control the engine and the motor according to the engine power generation travel mode and the execution range of the motor travel mode set by the travel mode setting unit when the vehicle travels in the low load section; Equipped with
The traveling mode setting unit sets a target charge amount of an amount that uses up the power generated in the engine power generation traveling mode at the end point of the low load section according to the motor traveling mode.
The low load travel control unit performs travel control of a hybrid vehicle that switches to the motor travel mode when the charge amount of the battery reaches the target charge amount by the electric power generated by the engine power generation travel mode in the low load section. apparatus.   The traveling mode setting unit sets an execution range of the engine power generation traveling mode and the motor traveling mode so that electric power generated in the engine power generation traveling mode is used up at the end point of the low load section according to the motor traveling mode. The travel control device of a hybrid vehicle according to claim 1. Based on the route information acquired by the pre-Symbol path information acquiring unit includes a charge amount prediction unit for predicting the amount of charge of the battery in the front of the vehicle on the route,
The low load travel control unit is set by the travel mode setting unit when the charge amount of the battery at the low load section start point predicted by the charge amount prediction unit is equal to or less than a predetermined amount previously determined. The travel control device for a hybrid vehicle according to claim 1 or 2, wherein the engine and the motor are controlled in accordance with an execution range of the engine power generation travel mode and the motor travel mode. The average torque calculation unit determines whether the calculated average required torque is lower than a fuel consumption determination threshold lower than the low load determination threshold,
When the average required torque is lower than the fuel efficiency determination threshold, the low load travel control unit performs the engine and the motor according to the engine power generation travel mode and the execution range of the motor travel mode set by the travel mode setting unit. travel control device for a hybrid vehicle according to any one of claims 1 to control 3. The low load travel control unit is set by the driver according to the engine power generation travel mode and the execution range of the motor travel mode set by the travel mode setting unit when the vehicle travels in the low load section. travel control device for a hybrid vehicle according to claim 1, any one of 4 for controlling the engine and the motor so as to maintain the target vehicle speed was. The hybrid vehicle travel control device according to any one of claims 1 to 5, wherein the engine power generation traveling mode generates electric power at an operating point of the engine at which fuel efficiency is optimal and the motor efficiency of the motor is the highest.

Images