JP2001169408A - Controller for hybrid car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid car which performs discharge and regenerative charging to its battery efficiently without damaging the drivability, when the present position of the car and height information of a road are detectable. SOLUTION: A permissible upper limit value for the quantity of discharge of the battery is set, considering the quantity of charging by regeneration to be expected in the course of descending a slope during time up to a maximum height point of a running route, on the basis of present position information of the car, road information including height information of the running route, and information on the remaining quantity of charging (SOC) of the battery, and adjustment is performed so that SOC may be a maximum value at the maximum height point of the running route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an engine and a motor, each of which is a combustion engine, as power sources, stores mechanical energy at the time of deceleration as electric energy, and uses this energy as the energy source of the motor at the time of re-acceleration. The present invention relates to a control device for a hybrid vehicle including an energy regenerating device for use as a vehicle.

[0002]

2. Description of the Related Art There is known a hybrid vehicle in which a motor and an engine are used in combination and these are used depending on the running state. Wheels are driven by motors, and engines operate only as a power supply to the motor.Generally, series hybrid systems, and systems in which an engine and a motor are used in parallel, and the driving force of the two is used appropriately to drive the vehicle are generally used. It is called a parallel hybrid system.

[0003] In these systems, a battery for supplying electric power to the motor is required, and the state of charge or remaining charge of the battery (hereinafter referred to as "SOC") is usually a median value between the upper and lower limits. It is controlled to be kept near. This is because, when the SOC is kept near the upper limit, the efficiency of charging is increased due to an increase in the chances of releasing charging energy to prevent overcharging, and when the SOC is near the lower limit, charging and discharging are performed in a state where the amount of charge is small. Is repeated, and such a use shortens the life of some batteries.

However, in such a control for keeping the SOC close to the median value, the range of the assisting force of the motor that can be used by charging and discharging the battery and the regenerative energy that can be stored are limited.
Since the upper and lower limit widths are limited to approximately ２, there is a possibility that a sufficient driving force may not be obtained during traveling under conditions where the load on the battery is large, such as when traveling in mountainous areas.

On the other hand, as a method of improving the energy efficiency of a hybrid vehicle, for example, Japanese Patent Laid-Open No.
No. 6, as disclosed in Japanese Patent Application Publication No. 6-200, the vehicle current position and the road information including the information of the altitude or the deceleration point are determined by S.
In some cases, an OC target value is set. According to this, for example, the SOC target can be set such that the highest position of the altitude becomes the lower limit value of the SOC, and the energy can be used efficiently.

[0006]

SUMMARY OF THE INVENTION However, SOC
When the output of the motor and the engine is adjusted so that they are close to the target value, the operation of the motor is determined in preference to the engine, and the degree to which the engine operating point deviates from the optimal fuel consumption position may increase. Nature occurs. For example, when the SOC is significantly lower than the target value, the charging request is temporarily excessively large, and if the vehicle is on an uphill, the engine removes the optimum fuel efficiency operating point and increases the output for charging, and if the vehicle goes downhill, For example, the generation of engine braking force due to fuel cut is prohibited, and the fuel efficiency tends to deteriorate.

[0007] When the altitude information is stored and used in a memory of a navigation system or the like, the target value of the SOC does not change smoothly unless detailed data is set, which promotes the problem of the operating point shift of the engine. Since it is conceivable that the fuel efficiency cannot be improved, it is necessary to set the altitude data in detail, which causes a problem that a large-capacity memory is required.

The present invention has been made in view of such a problem, and solves the above-mentioned conventional problems by predicting the energy balance of a hybrid vehicle based on information on an uphill section and a downhill section in a traveling route. The purpose is to eliminate.

[0009]

According to a first aspect of the present invention, there is provided a hybrid vehicle having a battery for driving a motor, and an energy regenerating device for charging the battery by generating power from an input from a vehicle drive system. Based on the road information including the information, the maximum altitude point on the traveling route of the vehicle from the current position, the distance of the uphill section from the maximum altitude point, the distance of the downhill section to the maximum altitude point, and the amount of altitude decrease are calculated. Calculating the SOC increase of the battery due to energy regeneration in the downhill section from the downhill section distance and the altitude decrease amount, and using the calculated value of the uphill section distance and the SOC increase, the vehicle reaches the highest altitude point. Is limited so that the SOC does not fall below the lower limit.

According to a second aspect of the present invention, in the first aspect of the invention, the SOC detecting means for detecting the remaining charge of the battery, the SOC minimum value setting means for setting the allowable minimum value of the SOC, and the current position of the vehicle Current position detecting means for detecting
Road information storage means for storing road information including altitude information, travel route setting means for setting a travel route ahead of the current position, position and altitude of altitude maximum point, altitude minimum point and maximum altitude point on the travel route And an altitude search means for searching for the distance based on the road information. The integrated distance of the uphill section from the current position to the highest altitude point is calculated, and the distance and altitude of the downhill section from the current position to the highest altitude point are calculated. Based on the amount of decrease, the amount of energy that can be regenerated in the downhill section or SO
The C increment prediction value is calculated, and the upper limit of the battery discharge amount per unit traveling distance is determined using the SOC current value, the allowable minimum value of the SOC, the integrated climbing distance, and the SOC increment prediction value.

According to a third aspect of the present invention, the uphill section and the downhill section in the above inventions are obtained based on the positions of the altitude maximum points and the altitude minimum points in the traveling route in the road information.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the upper limit value of the battery discharge amount per unit traveling distance is set to a difference between the current SOC value and the allowable minimum value of the SOC. It was set so as to be proportional to the sum of the predicted values and inversely proportional to the integrated climbing distance.

According to a fifth aspect of the present invention, in the method of the second or fourth aspect, when calculating the amount of regenerable energy in the downhill section, the ratio between the altitude decrease and the amount of regenerable energy is calculated by lowering the ratio. The determination is made based on the average downhill slope obtained by dividing the altitude decrease amount in the slope section by the section distance.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a ratio obtained by dividing the energy regenerable amount used for calculating the energy regenerable amount in the downhill section by the altitude reduction amount is used in the downhill section. When the absolute value of the average downhill slope obtained by dividing the altitude drop by the section distance is equal to or smaller than a predetermined reference value, the value is set to zero.

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, a ratio obtained by dividing the energy regenerable amount used for calculating the energy regenerable amount in the downhill section by the altitude decrease amount is always set to zero. I made it.

The invention according to claim 8 is the invention according to claims 2 to 7, further comprising a recommended travel route searching means for searching for a recommended travel route when a destination is set in advance. The traveling route is specified as the recommended traveling route.

According to a ninth aspect of the present invention, in accordance with the second to seventh aspects of the present invention, there is provided a traveling direction detecting means for detecting a current traveling direction of the vehicle. A plurality of routes having a high probability of being selected as a future traveling route are selected from the traveling direction and the road conditions, and the upper limit value of the battery discharging amount per unit traveling distance for the plurality of selected routes is calculated, and the battery discharging amount is calculated. As the upper limit, the vehicle travels by selecting a value between the minimum value and the maximum value of the upper limit of the battery discharge amount for each route.

According to a tenth aspect of the present invention, in accordance with the ninth aspect of the present invention, the upper limit value of the battery discharge amount calculated for each of a plurality of routes that are likely to be driving routes is set as the upper limit value of the battery discharge amount. Of the minimum values is selected.

According to an eleventh aspect of the present invention, in accordance with the ninth aspect of the present invention, the upper limit of the battery discharge amount is calculated for each of a plurality of routes which are likely to be selected as a traveling route. The upper limit value is calculated by weighting according to the probability that each route is selected.

[0020]

According to the first or second aspect of the present invention, an uphill section, a downhill section, and an altitude decrease amount in a traveling route are determined based on known road information such as a navigation system.
The highest altitude point is obtained, and the energy from the motor that can be distributed to the uphill section up to the highest altitude point is distributed. At this time, the battery discharge amount is limited by setting the upper limit value instead of giving the discharge target value. This makes it possible to control the remaining battery charge at the highest altitude point to be equal to or higher than the lower limit value,
It is possible to obtain a sufficient amount of energy regenerated for fuel economy, prevent a sudden discharge request, and smoothly change the output ratio between the motor and the engine.

The uphill section or the downhill section can be obtained by using the position data and the altitude data of the local maximum point and the local minimum point, that is, from the local maximum point to the local minimum point. Can be determined as a downhill section, and a section from the minimum point to the next maximum point can be determined as an uphill section. in this case,
Since it is not necessary to obtain and store the altitude information one by one, there is no inconvenience of consuming a large amount of memory.

According to the fourth aspect of the present invention, the energy from the distributable motor is obtained by adding a value obtained by converting the regenerable energy up to the highest altitude point into an SOC, to a margin to the lower limit of the SOC. Thus, it is possible to ensure that the SOC has an allowance for battery discharge until reaching the highest altitude point.

The invention according to claims 5 to 7 is characterized in that, even in a downhill section, in a gentle downhill section, the engine braking force due to the engine fuel cut is prioritized, or the driver does not decelerate and the regenerative power corresponding to the downhill amount is eventually obtained. Is considered not to be obtained. If the estimated amount of energy from the distributable motor is overestimated, the SOC will reach the minimum value sooner, and the control will be continued in a state where the acceleration will not be able to obtain the assist force by the motor, or will be less than the SOC minimum value,
This has an adverse effect on battery durability.

The invention as set forth in claim 8 and the following relates to the specification of a traveling route. The control according to the present invention cannot necessarily sufficiently exert an effect on fuel efficiency when the future traveling route is different from the assumed one. For example, if there is a high mountain near the expected route and suddenly change the route,
Acceleration that cannot obtain the assist force by the motor,
The control is continued in a state where the SOC is lower than the minimum SOC value, which may adversely affect the durability of the battery. Therefore,
It is necessary to set a highly accurate traveling route. On the other hand,
In practice, setting a destination by a navigation system or the like is not always performed, but even in such a case, it is desirable to improve the fuel efficiency as much as possible.

Therefore, according to the invention of claim 8, when a driver or the like sets a destination in advance in the navigation system or the like, a travel route recommended by the navigation system is selected. On the other hand, in the invention after claim 9, even if the destination is not selected, the traveling direction and the road condition of the vehicle are acquired from the existing navigation system and the like, and a route considered as a future traveling route is assumed to some extent. Then, for example, in the invention of claim 10, a minimum value is selected as a discharge allowable value per unit traveling distance, thereby minimizing the above-mentioned inconvenience and improving fuel economy to some extent. It is possible to drive at an improved rate. Further, according to the invention of claim 11, by weighting according to the possibility of being selected from the assumed traveling routes, the weight of the traveling route is appropriately selected without depending on only the discharge allowable value and emphasizing the probability of selecting the traveling route. Control can be performed.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of a hybrid vehicle according to the present embodiment. The control system for a hybrid vehicle according to the present embodiment includes an engine 1, a motor 2, a brake 3, and a controller 4 that controls these components as elements for generating a driving force and a braking force. The motor 2 is a rotating electric machine having both functions of an electric motor and a generator. The motor 2 exhibits a traveling driving force as an electric motor according to an operating state, and an energy regenerating device by an input from a driving system when the vehicle is decelerating or traveling downhill. It operates as a generator. The controller 4 is constituted by a microcomputer system including a CPU, an input / output circuit, a memory, and the like, and performs various means of the present invention or functions of determination, calculation, and the like. As a peripheral system, a navigation system 5 that can obtain road information including the current position and altitude information of the vehicle, and a battery 6 for supplying electric power to the motor 2 are provided. The controller 4 has an accelerator sensor signal i- indicating an accelerator operation amount as a control input signal.
1. Brake sensor signal i-2 indicating the amount of brake operation,
The battery 6 is provided with an SOC detection means 7 for detecting the vehicle speed sensor signal i-3 and the like indicating the traveling speed of the vehicle, and the SOC detection signal i-4 is input to the controller 4.

The controller 4 includes, as control blocks, a power train control system section 41 for calculating a target driving force and a target braking force based on a control input signal, and a transmission from the target driving force and the target braking force and the navigation system 5. A driving force / braking force distribution unit 42 that determines a control amount for the engine 1, the motor 2, and the brake 3 based on information on road conditions and the like received from the vehicle and the remaining battery level SOC sent from the SOC detection unit 7. , An engine control system unit 43 for controlling the engine 1, a motor control system unit 4 for controlling the motor
4. Brake control system unit 45 for controlling brake 3
It has.

When the vehicle is accelerating or running steadily, the power train control system section 41 outputs the accelerator sensor signal i-
Based on 1 and the vehicle speed sensor signal i-3, a target driving force is calculated by a map search. As shown in FIG. 2, there is a region where the fuel efficiency is optimal on the operating point of the engine, but the target driving force requested by the driver cannot always be realized using the region where the fuel efficiency is optimal. . Therefore, the engine 1 is operated so as to trace a point where the fuel efficiency is always optimal in a region equal to or less than the target driving force, and the output shortage is instructed to the motor control system unit 44 as the driving force target value of the motor 2.

At the time of deceleration, the power train control system 41 calculates a target deceleration force based on the brake sensor signal i-2 and the vehicle speed sensor signal i-3. In this case, the engine 1 stops or generates an engine braking force while preventing unnecessary consumption of fuel by fuel cut. The power generation by the motor 2 is controlled so that the maximum amount of energy regenerated is obtained by subtracting the engine braking force from the target deceleration force. If the braking force is further insufficient, a command is issued to the brake control system unit 45 to be covered by the braking device.

The navigation system 5 includes a GPS device for specifying the position of the vehicle using an artificial satellite, and searches for road information stored in advance in a data file such as a CD-ROM. It can be transmitted to the powertrain control system along with the information.
Here, the road information stored in the data file includes:
When the navigation route is searched by the navigation system, the information on the altitude maximum point and the minimum point of the road on the traveling route is included in the power train control system. It is transmitted to the unit 41.

FIG. 3 shows a control flow executed by the controller 4 when a destination is set in advance. This control routine is repeatedly executed at a cycle of, for example, 10 msec. First, when a destination is input to the navigation system by the operator, a travel route to the destination is searched by a known method based on the road information prepared by the data file (steps 301 and 30).
2). Next, the current SOC is detected by the SOC detection means 7 and input to the power train control system unit 41 (step 303). Next, it is determined from the GPS signal whether or not the searched traveling route is actually traveling. If the traveling route is deviated, the calculation is stopped (step 30).
4). Next, information on the maximum altitude point, the minimum point, and the maximum altitude point on the traveling route is acquired from the road information of the navigation system, and transmitted to the power train control system unit 41 (step 305). Power train control system section 41
Calculates the distance between each maximum point and the minimum point and the amount of altitude descent,
From the distance and altitude difference of the downhill traveling section obtained as a result, SO
In addition to calculating the predicted value of the C increment (the power for energy regeneration obtained when traveling downhill), the battery allowable discharge rate is calculated from the integrated distance of the uphill section (step 306).
307, 308).

Next, the target driving force is obtained by searching a map or the like based on the driving state signals such as the accelerator sensor signal i-1, the vehicle speed sensor signal 1-3 and the like (steps 309 and 31).
0). Further, based on information on the vehicle state such as the vehicle speed and the engine rotation, the output distribution ratio between the engine and the motor is calculated by a predetermined method (steps 311 and 31).
2). Specifically, as described above, first, a combination of the target engine rotation and the target engine torque is set so as to optimize the fuel consumption of the engine, and a shortage with respect to the target driving force is supplemented as a motor command value. The thus obtained discharge command value to the motor is compared with the allowable discharge ratio calculated in advance in step 308, and if it is more than the allowable discharge ratio, the discharge command value is set as the allowable discharge ratio. An insufficient engine torque is calculated and set as a target engine torque (steps 313 to 316). If the discharge command value is equal to or less than the allowable discharge ratio, it is output as it is as the motor command value.

FIG. 4 shows the SOC,
A specific control example of the allowable discharge ratio will be described. The SOC measurement value at the current location is SOCc, and the upper and lower limits of the SOC are SOCmax and SOCmin.

Between the current position Pc and the destination Po, the local maximum points T1, T
2, T3, and the minimum points B1, B2. T1, T2, T3
The highest altitude T3 is the highest altitude point. Also T
1, T2, T3, B1, B2 each altitude is ht1, ht
2, ht3, hb1, hb2. Pc ~ T1, T1 ~ B1, B1
Sections from T2 to T2 to B2, B2 to T3, and T3 to Po are named U1, D1, U2, D2, U3, and D3, respectively. U indicates an uphill section, and D indicates a downhill section. The respective section distances are Lu1, Ld1, Lu2, Ld2
Lu3, Ld3, descending section D to the highest point of the section
Δhd1 = ht
1−hb1, Δhd2 = ht2−hb2.

Since the average downhill gradient is small in the section D1, the predicted SOC increase value in this section is set to zero. Section D
2 is a relatively large descending slope, so the altitude decrease Δ
A value obtained by multiplying hd2 by a coefficient can be expected as the SOC increment.

Therefore, the uphill distance ΣLu to the highest altitude point at the current position is: ΣLu = Lu1 + Lu2 + Lu3 The predicted SOC increase value IncSOC is: IncSOC = Δhd2 × t where t is a coefficient that depends on Δhd2 / Ld2, and Allowable discharge rate Cm
ax is Cmax = a × (SOCc−SOCmin + IncSOC) / ΣLu where a is the ratio of the discharge amount to the SOC change amount. here,
In order to obtain the allowable discharge rate per unit time, Cmax may be multiplied by the vehicle speed.

FIG. 4 shows a second embodiment of the present invention.
The flow of control corresponding to the ninth and following aspects of the invention, that is, the flow of control when the destination is not specified in the navigation system will be described. In this control, first, from information on the current position and the traveling direction of the vehicle, a maximum of n traveling routes K which are likely to travel in the future are estimated on a main road close to the current position (steps 501 and 5020). Next, for each of the estimated traveling routes K1 to Kn,
The maximum altitude point information, the minimum altitude point information, and the maximum altitude point information within a predetermined distance from the current location are searched from the road information data of the navigation system, and the allowable information for each traveling route is searched in the same manner as in the first embodiment. The discharge ratio is calculated (steps 503 to 507). Next, for example, a value having the smallest allowable discharge ratio is determined from the allowable discharge ratios for the respective traveling routes, and is set as a final allowable discharge ratio (step 508). The control (steps 509 to 516) after the allowable discharge ratio is determined is the same as in the case of FIG. 3 (steps 309 to 316).

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a hybrid vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an engine operating point of the hybrid vehicle according to one embodiment of the present invention.

FIG. 3 is a control flowchart of the first embodiment of the hybrid vehicle according to the present invention.

FIG. 4 is an explanatory diagram showing a specific control example of a remaining battery state and an allowable discharge ratio according to the first embodiment.

FIG. 5 is a control flowchart of a second embodiment of the hybrid vehicle according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 motor 3 brake 4 controller 41 power train control system unit 42 driving force / braking force distribution unit 43 engine control system 44 motor control system 45 brake control system 5 navigation system 6 battery 7 battery remaining amount detection device i-1 accelerator sensor Signal i-2 Brake sensor signal i-3 Vehicle speed sensor signal i-4 Battery level detection signal

Continued on the front page F term (reference) 3G093 AA07 AA16 BA19 CB07 DA01 DB00 DB05 DB15 DB18 FA11 FB05 5H115 PA12 PC06 PG04 PI16 PI22 PI29 PO02 PO06 PU01 PU23 PU25 QE04 QE06 QI04 QI07 QI09 QI15 QN03 QN23 QN27 SL01 TE12 SL01 TI02 TO08 TO21 TO23

Claims (11)

[Claims] 1. A hybrid vehicle comprising: a battery for driving a motor; and an energy regenerating device for generating power from an input from a vehicle drive system and charging the battery, based on road information including altitude information. The highest altitude point on the traveling route of the vehicle, the distance of the uphill section between the highest altitude point, the distance of the downhill section to the highest altitude point, and the altitude decrease amount are obtained, and the downhill section distance, the altitude decrease amount, Calculates the SOC increment of the battery due to energy regeneration in the downhill section from the above, and calculates the battery discharge amount until the vehicle reaches the highest altitude point by using the calculated value of the uphill section distance and the SOC increment. A hybrid vehicle control device that restricts the vehicle from becoming inconsistent. 2. The apparatus includes an SOC detecting means for detecting the remaining charge of the battery, an SOC minimum value setting means for setting an allowable minimum value of the SOC, a current position detecting means for detecting a current position of the vehicle, and altitude information. Road information storage means for storing road information, traveling route setting means for setting a traveling route ahead of the current position, and the position and altitude of the altitude maximum point, the altitude minimum point and the maximum altitude point on the traveling route as road information. And a position / altitude search means for performing a search based on the distance of the downhill section from the current position to the highest altitude point and the altitude decrease amount. In this case, the regenerable amount of energy or the predicted value of the SOC increase in the downhill section is calculated, and the upper limit value of the battery discharge amount per unit traveling distance is determined by the SOC current value, the allowable minimum value of the SOC, and the integrated uphill. Distance, and SO
The control device for a hybrid vehicle according to claim 1, wherein the control device is determined by using a C increment prediction value. 3. The uphill section and the downhill section are determined based on the position of the maximum altitude point and the position of the minimum altitude point in the traveling route in the road information.
The control device for a hybrid vehicle according to any one of the above. 4. An upper limit value of a battery discharge amount per unit traveling distance is defined as a difference between an SOC present value and an allowable minimum value of the SOC.
3. The hybrid vehicle control device according to claim 2, wherein the control value is proportional to the sum of the predicted OC increment and inversely proportional to the integrated climbing distance. 5. When calculating the amount of energy regenerable in a downhill section, the ratio between the altitude decrease amount and the energy regenerable amount is calculated as an average downhill slope obtained by dividing the altitude decrease amount in the downhill section by the section distance. The control device for a hybrid vehicle according to claim 2, wherein the control device is determined based on the condition. 6. A ratio obtained by dividing the amount of regenerative energy used for calculating the amount of regenerable energy in a downhill section by the amount of decrease in altitude is an average downhill slope obtained by dividing the amount of decrease in altitude in a downhill section by the section distance. The hybrid vehicle control device according to claim 5, wherein when the absolute value of is less than or equal to a predetermined reference value, the value is zero. 7. The hybrid vehicle control device according to claim 5, wherein a ratio obtained by dividing the energy regeneration amount used in calculating the energy regeneration amount in the downhill section by the altitude decrease amount is always zero. 8. A recommended travel route searching means for searching for a recommended travel route when a destination is set in advance, and when a destination is set, a travel route is specified as the recommended travel route. The control device for a hybrid vehicle according to any one of the above. 9. A vehicle having a traveling direction detecting means for detecting a traveling direction of a current vehicle, and when a destination is not set, a probability that a future traveling route is selected as a traveling route from a traveling direction and road conditions. And calculating the upper limit of the battery discharge amount per unit traveling distance for the plurality of selected routes, and the upper limit of the battery discharge amount is the minimum value of the upper limit of the battery discharge amount for each route. The hybrid vehicle control device according to any one of claims 2 to 7, wherein the vehicle travels while selecting a value between the maximum value and the maximum value. 10. The battery discharge amount upper limit value is selected from the minimum value of the battery discharge amount upper limit values calculated for each of a plurality of routes that are likely to be travel routes. Hybrid vehicle control device. 11. The upper limit value of the battery discharge amount is determined based on the probability that each route is selected with respect to the upper limit value of the battery discharge amount calculated for each of a plurality of routes that are likely to be selected as a traveling route. The control device for a hybrid vehicle according to claim 9, wherein the control is performed by weighting according to: