JP4888776B2 - Vehicle power generation control device - Google Patents

Description

  The present invention relates to a vehicle power generation control device having a function of controlling a generator in consideration of an increase in fuel consumption due to power generation by the generator.

  As shown in Patent Document 1 (Japanese Patent Laid-Open No. 2000-4502), the generator (alternator) mounted on the vehicle is controlled by monitoring the state of charge (SOC) of the battery and charging the battery. In many cases, the amount of power generation is controlled by controlling the control current (field current) of the generator so as not to become insufficient.

  Further, as shown in Patent Document 2 (Japanese Patent Laid-Open No. 2005-160269), in order to charge the battery efficiently, regenerative power generation is performed by driving the generator with the deceleration energy of the vehicle in the downhill section of the travel route. In addition, there is a battery that charges the regenerative power generated by the battery. Furthermore, in this patent document 2, the downhill section of the travel route is predicted based on the road map information of the navigation system, and the SOC of the battery is at or near the allowable lower limit value at the start point of the downhill section. The target SOC of the battery is set.

  By the way, since the power generation amount that can be regenerated in the downhill section changes depending on the slope and distance of the road, the SOC of the battery is at or near the allowable lower limit at the start point of the downhill section as in Patent Document 2 above. Thus, when the target SOC of the battery is set, when the amount of regenerative power generation in the downhill section is small, the SOC of the battery is not sufficiently recovered by the end point of the downhill section.

Therefore, in Patent Document 2, the SOC change amount (power generation amount) due to regenerative power generation in the downhill section is predicted, and when the predicted SOC change amount is small, the target SOC of the battery at the start point of the downhill section is The SOC of the battery is controlled in the vicinity of the median value between the allowable upper limit value and the allowable lower limit value by setting the SOC lower than the median value between the allowable upper limit value and the allowable lower limit value by ½ of the predicted SOC change amount. I am doing so.
JP 2000-4502 A JP 2005-160269 A

  Since the generator is driven by the power of the internal combustion engine (engine) to generate electric power, at the time of power generation, extra fuel is consumed according to the load that drives the generator. The increase in fuel consumption per unit power generation (hereinafter referred to as “electricity cost”) varies depending on the driving conditions of the vehicle, the slope of the road surface, etc., so the power consumption before the downhill section starts and the power consumption after the downhill section ends. In some cases, the power consumption of either one is high and the other is low. In order to reduce the average fuel consumption of the vehicle, it is desirable to increase the amount of power generation in a section where the electricity cost is low and decrease the amount of power generation in a section where the power cost is high.

  However, in Patent Document 2, when the amount of regenerative power generation in the downhill section is small, the SOC of the battery at the end of the downhill section is an allowable upper limit value and an allowable lower limit value regardless of the power consumption before and after the downhill section. For example, if the electricity cost before the start of the downhill section is low and the electricity cost after the end of the downhill section is high, the power generation amount after the end of the downhill section where the electricity cost is high There is a problem that the average fuel consumption of the vehicle is deteriorated.

  The present invention has been made in view of such circumstances, and therefore the object thereof is to control the power generation of the generator so that the average fuel consumption of the vehicle is reduced in consideration of the power consumption before and after the regenerative power generation section. An object of the present invention is to provide a vehicular power generation control device capable of performing

  In order to achieve the above object, an invention according to claim 1 includes a generator driven by the power of an internal combustion engine, a battery charged with electric power generated by the generator, and the power generation during operation of the internal combustion engine. Power consumption calculation means for calculating the fuel consumption increase per unit power generation (hereinafter referred to as “electricity cost”) based on the fuel consumption increase by the power generation of the engine and the power generation amount, and the power consumption during the operation of the internal combustion engine Power consumption calculating means for calculating, SOC determining means for determining the state of charge of the battery (hereinafter referred to as “SOC”), and the generator with the deceleration energy of the future vehicle based on the road map information of the navigation system. Regenerative power generation section that drives and generates power, regenerative power generation information prediction means that predicts the amount of regenerative power generation, and power generation control that controls power generation of the generator so that the SOC of the battery matches the target SOC The power consumption calculation means predicts the power consumption before and after the regenerative power generation section before the regenerative power generation section starts, and the power consumption calculation means calculates the regenerative power generation section before the regenerative power generation section starts. The SOC determination means predicts a predicted SOC change amount of the regenerative power generation section based on a difference between the regenerative power generation amount and the power consumption amount before the regenerative power generation section starts, The power generation control unit is configured to set the target SOC based on a power consumption before and after the regenerative power generation section and a predicted SOC change amount of the regenerative power generation section.

  According to this configuration, considering the electricity costs before and after the regenerative power generation section, at the start of the regenerative power generation section, the power generation amount in the section with the higher power consumption is reduced and the power generation amount in the section with the lower power consumption is increased. Alternatively, it is possible to control the setting of the target SOC at the end of the regenerative power generation period, thereby ensuring the increase in fuel consumption due to power generation while controlling the SOC of the battery within the allowable upper limit value and the allowable lower limit value. It is possible to reduce the average fuel consumption of the vehicle.

  In this case, as in claim 2, when the predicted SOC change amount in the regenerative power generation section is larger than the width between the allowable upper limit value and the allowable lower limit value of the SOC, the SOC at the start of the regenerative power generation section is The target SOC may be set so as to be at or near the allowable lower limit value. In this way, the maximum allowable regenerative power generation amount can be charged in the battery in the regenerative power generation section, and the power generation amount before and after the regenerative power generation section can be reduced.

  Further, as in claim 3, when the predicted SOC change amount in the regenerative power generation section is smaller than the width between the allowable upper limit value and the allowable lower limit value of the SOC, the power consumption before and after the regenerative power generation section is compared. When the electricity cost before the regenerative power generation section is lower than the power cost after the regenerative power generation section, the target SOC is set so that the SOC at the end of the regenerative power generation section is at or near the allowable upper limit value, When the power consumption before the regenerative power generation section is higher than the power consumption after the regenerative power generation section, the target SOC may be set so that the SOC at the start of the regenerative power generation section is at or near the allowable lower limit value. In this way, comparing the electricity costs before and after the regenerative power generation section, at the start of the regenerative power generation section to reduce the power generation amount in the section with the higher power consumption and increase the power generation amount in the section with the lower power consumption Alternatively, the target SOC at the end of the regenerative power generation section can be set.

  In this case, as in claim 4, the regenerative power generation section may be predicted by predicting the fuel cut start point and the duration of the fuel cut based on the road map information of the navigation system. Here, the point where the fuel cut is started is, for example, a start point of a downhill road or a point where the vehicle starts to decelerate immediately before turning right or left. The duration of the fuel cut corresponds to the regenerative power generation time.

  Further, as in claim 5, the road map information of the navigation system includes road gradient information, and the fuel cut start point and the fuel cut start point based on the road gradient information and the vehicle speed information. It is also possible to predict the regenerative power generation section by predicting the continuation time. This is because, even on a downhill road, fuel cut is not performed when the gradient is small or the vehicle speed is low.

  Further, as described in claim 6, the road gradient information may be set for each point where the road gradient changes. In this way, the data amount of road gradient information can be reduced.

  In addition, as described in claim 7, the road gradient information includes road elevation information and distance information between the points set for each point where the road gradient changes. A road slope is calculated based on the distance, and the regenerative power generation section is predicted by predicting the fuel cut start point and the duration of the fuel cut based on the road slope and vehicle speed information. May be. In this case, the distance between the points may be the road travel distance between the points, or the horizontal distance of the road between the points. The road gradient can be calculated by the combination of

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment embodying the best mode for carrying out the invention will be described with reference to the drawings.
A control device 11 shown in FIG. 1 is supplied with power from a battery 12 via a key switch 13, controls the operation of the ignition device 14 and the injection device 15 during engine operation, and generates power from a generator 16 (alternator). It functions as a power generation control means for controlling.

  The control device 11 calculates the state of charge (SOC) of the battery 12 based on the charge / discharge current of the battery 12 detected by the current sensor 17 and / or the open terminal voltage of the battery 12 detected by the voltage sensor 18. To do. For example, the charge / discharge current of the battery 12 is detected by the current sensor 17 and the detected values are integrated. At this time, the charging current of the battery 12 is set to a positive value, and the discharging current of the battery 12 is set to a negative value, so that the integrated charging / discharging current value is increased or decreased according to the SOC of the battery 12. Thereby, the charge / discharge current integrated value can be used as the SOC detection data of the battery 12. Or you may make it calculate SOC according to the open terminal voltage of the battery 12 with reference to the map showing the relationship between the open terminal voltage of the battery 12 and SOC. Of course, the SOC of the battery 12 may be calculated based on both the charge / discharge current integrated value of the battery 12 and the open terminal voltage.

  FIG. 2 is a diagram showing the relationship between the fuel consumption rate, which is the fuel consumption per unit time, and the engine operating conditions. As shown in FIG. 2, the fuel consumption rate changes depending on the engine speed and the engine torque. Since the fuel consumption rate changes in a curve according to the engine torque, when the engine rotational speed is constant, there are a condition where the increase amount of the fuel consumption rate is large and a condition where the increase amount is small. For example, when a certain amount of power is generated by the power generator 16, the torque generated by the power generator 16 is added to the engine torque by power generation, and the operating point of the engine changes. For this reason, a fuel consumption rate changes with electric power generation amounts. At this time, if only a condition with a low fuel consumption rate is selected and power generation is performed, the fuel consumption rate can be reduced.

  Therefore, in this embodiment, an increase in fuel consumption rate per unit power generation amount (hereinafter referred to as “electricity cost”) is used as a parameter for power generation control. This electricity cost is calculated by the control device 11 as follows.

First, while the engine is running (running), the fuel consumption rate when the generator 16 generates power (fuel consumption rate during power generation) and the fuel consumption rate when the generator 16 stops power generation (non-power generation fuel) The increase in fuel consumption rate due to power generation is calculated from the difference from the consumption rate), and the increase in fuel consumption rate due to power generation is divided by the power generation amount of the generator 16 to calculate the power consumption (increase in fuel consumption per unit power generation amount). Ask.
Electricity cost (g / skW) = (Fuel consumption rate during power generation-Fuel consumption rate during non-power generation) / Power generation amount

Further, the control device 11 reads the road map information stored in the memory of the navigation system 19, and based on this road map information, drives the generator 16 with the deceleration energy of the future vehicle to generate power and the regenerative power generation section and the regenerative section. Predict power generation. Then, before the regenerative power generation section starts, the average power consumption of the predetermined section before and after the regenerative power generation section is predicted, the power consumption of the regenerative power generation section is predicted, and the SOC change amount of the regenerative power generation section is further calculated. Based on the difference between the regenerative power generation amount and the power consumption amount in the regenerative power generation section, the following formula is used for prediction.
SOC change amount of regenerative power generation section = (regenerative power generation amount−power consumption amount) / battery capacity × 100
In the above equation, the amount of regenerative power generation and the amount of power consumption are integrated values of the regenerative power generation section.

  And the control apparatus 11 sets target SOC as follows based on the average electricity consumption of the predetermined area before and behind a regenerative power generation area, and the prediction SOC variation | change_quantity of a regenerative power generation area.

  (1) When the predicted SOC change amount in the regenerative power generation section is larger than the range between the allowable upper limit value and the allowable lower limit value of the SOC of the battery 12, as shown in FIG. The target SOC is set so as to be the allowable lower limit value (or the vicinity thereof).

  (2) When the predicted SOC change amount in the regenerative power generation section is smaller than the width between the allowable upper limit value and the allowable lower limit value of the SOC of the battery 12, the average power consumption in the predetermined section before and after the regenerative power generation section is compared. As shown in FIG. 4, when the average power consumption in the predetermined section before the regenerative power generation section is lower than the average power consumption in the predetermined section after the regenerative power generation section, the SOC at the end of the regenerative power generation section is an allowable upper limit value (or its vicinity) ) To set the target SOC.

  On the other hand, as shown in FIG. 5, when the average power consumption in the predetermined section before the regenerative power generation section is higher than the average power consumption in the predetermined section after the regenerative power generation section, the SOC at the start of the regenerative power generation section is an allowable lower limit (or The target SOC is set so that

  In this case, the method for predicting the regenerative power generation section predicts the regenerative power generation section by predicting the fuel cut start point and the duration of the fuel cut based on the road map information of the navigation system 19. Here, the point where the fuel cut is started is, for example, a start point of a downhill road or a point where the vehicle starts to decelerate in order to turn right or left in the traveling direction. The duration of the fuel cut corresponds to the regenerative power generation time.

  As a means for predicting the start point of the downhill road, the road map information of the navigation system 19 is provided with road slope information, and the fuel cut is started based on the road slope information and the vehicle speed information. The duration of the fuel cut may be predicted to predict the regenerative power generation section. This is because, even on a downhill road, fuel cut is not performed when the gradient is small or the vehicle speed is slow. The vehicle speed information may be learned and stored in a memory.

  In addition, as shown in FIG. 6, the road slope information includes road elevation information and distance information between each point where the road slope changes. A road slope is calculated based on the distance, and the regenerative power generation section is predicted by predicting the fuel cut start point and the duration of the fuel cut based on the road slope and vehicle speed information. May be.

  In this case, as shown in FIG. 6, the distance between the points may be the road traveling distance c between the points, or the horizontal distance a of the road between the points. The horizontal distance a of the road between points may be calculated from the latitude and lightness of each point.

The gradient may be calculated by the following equation, or the slope angle θ may be calculated.
Gradient = b / a × 100 [%]
θ = tan ⁻¹ (b / a) or θ = sin ⁻¹ (b / c)
Further, if the road passes frequently, the regenerative power generation section (fuel cut section) may be learned and stored in the memory.
Next, the processing content of each routine of FIG. 7 thru | or FIG. 9 which the control apparatus 11 performs is demonstrated.

[Regenerative power generation information prediction routine]
The regenerative power generation information prediction routine of FIG. 7 is executed at a predetermined cycle during engine operation, and plays a role as regenerative power generation information prediction means in the claims. When this routine is started, first, in step 101, the gradient of a predetermined section of the travel route ahead of the current location is read, and in the next step 102, the predicted vehicle speed of the predetermined section is read. If this road speed predicted value is a road that passes frequently, the vehicle speed learned when traveling on the road may be used, or the relationship between the road gradient and the vehicle speed is learned, and a predetermined section is obtained from the learned data. You may make it obtain | require the vehicle speed according to the gradient.

  Thereafter, the process proceeds to step 103, where it is determined whether or not the predetermined section is a downhill road with a possibility of fuel cut (regenerative power generation) depending on whether or not the gradient of the predetermined section is less than the determination value k. In the case of a downhill road, since the gradient becomes a negative value, the determination value k is also set to a negative value.

  If it is determined in step 103 that the gradient of the predetermined section is less than the determination value k, it is determined that the road has a possibility of fuel cut (regenerative power generation), and the process proceeds to step 104 where the slope of the downhill road is determined. Based on the predicted vehicle speed, the fuel cut start point (that is, the start point of the regenerative power generation section) is predicted, and in the next step 105, the fuel cut duration (that is, the regenerative power generation section duration) is predicted. This routine is terminated.

  On the other hand, if it is determined in step 103 that the gradient of the predetermined section is not less than the determination value k, it is determined that a fuel cut (regenerative power generation) by the downhill road does not occur, the process proceeds to step 107, and ahead of the current location. It is determined whether there is a right turn or left turn point at which a fuel cut during deceleration occurs within a predetermined section of the travel route. If there is no right turn or left turn point, the present routine is terminated.

  On the other hand, if it is determined in step 107 that there is a right or left turn point at which the fuel cut during deceleration occurs, the process proceeds to step 108, the right turn or left turn point is read, and the fuel during deceleration is read in the next step 109. The cut time (that is, regenerative power generation time) is calculated, and this routine is terminated.

[Target SOC setting routine]
The target SOC setting routine of FIG. 8 is executed at a predetermined cycle during engine operation, and serves as power generation control means in the claims. When this routine is started, first, in step 201, road map information of the navigation system 19 is read, and in the next step 202, the engine speed and the engine torque are estimated.

  Then, it progresses to step 203 and calculates the average electricity consumption of the predetermined area before and behind a regenerative electric power generation area. The processing in step 203 serves as a power consumption calculation unit. Then, in the next step 204, the power consumption amount in the regenerative power generation section is estimated. The processing in step 204 serves as power consumption calculation means.

Thereafter, the process proceeds to step 205, and the SOC change amount (ΔSOC) in the regenerative power generation section is predicted based on the difference between the regenerative power generation amount and the power consumption amount in the regenerative power generation section by the following equation.
ΔSOC of regenerative power generation section = (regenerative power generation amount−power consumption amount) / battery capacity × 100
In the above equation, the amount of regenerative power generation and the amount of power consumption are integrated values of the regenerative power generation section.
The process of step 205 serves as an SOC determination unit.

  Thereafter, the process proceeds to step 206, where ΔSOC of the regenerative power generation section is compared with the width between the allowable upper limit value and the allowable lower limit value of the SOC of the battery 12 (hereinafter referred to as “upper / lower limit width”), and ΔSOC of the regenerative power generation section. Is equal to or greater than the upper / lower limit width, the process proceeds to step 207, and as shown in FIG. 3, the target SOC at the start of the regenerative power generation section is set to the allowable lower limit value (or the vicinity thereof).

  On the other hand, if it is determined in step 206 that the ΔSOC of the regenerative power generation section is smaller than the upper and lower limit width, the process proceeds to step 208 to compare the average power consumption of the predetermined section before and after the regenerative power generation section and If it is determined that the average power consumption of the predetermined section before the power generation section is lower than the average power consumption of the predetermined section after the regenerative power generation section, the process proceeds to step 209 and, as shown in FIG. 4, the target SOC at the end of the regenerative power generation section Is set to the allowable upper limit value (or the vicinity thereof).

  If it is determined in step 208 that the average power consumption of the predetermined section before the regenerative power generation section is higher than the average power consumption of the predetermined section after the regenerative power generation section, the process proceeds to step 210, as shown in FIG. The target SOC at the start of the regenerative power generation section is set to the allowable lower limit value (or its vicinity).

[Power generation control routine]
The power generation control routine of FIG. 9 is executed at predetermined intervals during engine operation, and serves as power generation control means in the claims. When this routine is started, first, in step 301, the actual SOC of the battery 12 is calculated based on the charge / discharge current of the battery 12 detected by the current sensor 17 and / or the open terminal voltage of the battery 12 detected by the voltage sensor 18. To do. The process of step 301 serves as the SOC determination means in the claims.

  Thereafter, the process proceeds to step 302, and the target SOC set in the target SOC setting routine of FIG. 8 is read. In the next step 303, the power generation amount is controlled by controlling the control current (field current) of the generator 16 by PID control or the like so as to reduce the deviation between the actual SOC and the target SOC.

  According to the present embodiment described above, the power generation before and after the regenerative power generation section is taken into consideration, the power generation amount in the section with higher power consumption is reduced, and the power generation amount in the section with lower power consumption is increased. Control of setting the target SOC at the start of the power generation section or at the end of the regenerative power generation section is possible, thereby controlling the SOC of the battery 12 within the range between the allowable upper limit value and the allowable lower limit value, and fuel consumption by power generation The amount of increase can be reliably reduced, and the demand for reduction in average fuel consumption of the vehicle can be satisfied.

It is a block diagram explaining the system configuration | structure of one Example of this invention. It is a figure which shows the relationship between a fuel consumption rate and an engine driving | running condition. It is a figure explaining the SOC control method in case the prediction SOC variation | change_quantity of a regenerative electric power generation area is larger than the width | variety between the allowable upper limit of a battery's SOC, and an allowable lower limit. When the predicted SOC change amount in the regenerative power generation section is smaller than the width between the allowable upper limit value and the allowable lower limit value of the SOC of the battery, the average power consumption of the predetermined section before the regenerative power generation section is the predetermined section after the regenerative power generation section. It is a figure explaining the SOC control method when it is cheaper than the average power consumption. When the predicted SOC change amount in the regenerative power generation section is smaller than the width between the allowable upper limit value and the allowable lower limit value of the SOC of the battery, the average power consumption of the predetermined section before the regenerative power generation section is the predetermined section after the regenerative power generation section. It is a figure explaining the SOC control method when it is higher than the average power consumption. It is a figure explaining the method to acquire the information of the slope of a slope. It is a flowchart which shows the flow of a process of a regenerative power generation information prediction routine. It is a flowchart which shows the flow of a process of target SOC setting routine. It is a flowchart which shows the flow of a process of an electric power generation control routine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Control apparatus (Power generation control means, SOC determination means, Power consumption calculation means, Power consumption calculation means, Regenerative power generation information prediction means), 12 ... Battery, 13 ... Key switch, 16 ... Generator, 17 ... Current sensor, 18 ... Voltage sensor, 19 ... Navigation system

Claims (7)

A generator driven by the power of the internal combustion engine;
A battery charged with electric power generated by the generator;
A power consumption calculating means for calculating a fuel consumption increase per unit power generation amount (hereinafter referred to as “electricity cost”) based on the fuel consumption increase amount and the power generation amount generated by the generator during operation of the internal combustion engine; Power consumption calculating means for calculating power consumption during operation of the engine;
SOC determination means for determining the state of charge of the battery (hereinafter referred to as “SOC”), and a regenerative power generation section that generates power by driving the generator with deceleration energy of a future vehicle based on road map information of a navigation system Regenerative power generation information prediction means for predicting the amount of regenerative power generation, and power generation control means for controlling the power generation of the generator so that the SOC of the battery matches the target SOC,
The power consumption calculation means predicts power consumption before and after the regenerative power generation section before the regenerative power generation section starts,
The power consumption calculation means predicts the amount of power consumption of the regenerative power generation section before the regenerative power generation section starts,
The SOC determination means predicts an SOC change amount of the regenerative power generation section based on a difference between the regenerative power generation amount and the power consumption amount before the regenerative power generation section starts,
The vehicle power generation control device, wherein the power generation control unit sets the target SOC based on a power consumption before and after the regenerative power generation section and a predicted SOC change amount of the regenerative power generation section.   When the predicted SOC change amount of the regenerative power generation section is larger than the width between the allowable upper limit value and the allowable lower limit value of the SOC, the power generation control means determines that the SOC at the start of the regenerative power generation section is the allowable lower limit value. 2. The vehicle power generation control device according to claim 1, wherein the target SOC is set so as to be in the vicinity thereof.   When the predicted SOC change amount in the regenerative power generation section is smaller than the width between the allowable upper limit value and the allowable lower limit value of the SOC, the power generation control means compares the power consumption before and after the regenerative power generation section, When the power consumption before the regenerative power generation section is lower than the power consumption after the regenerative power generation section, a target SOC is set so that the SOC at the end of the regenerative power generation section is at or near the allowable upper limit value, and the regenerative power generation The target SOC is set so that the SOC at the start of the regenerative power generation section is at or near the allowable lower limit when the power consumption before the section is higher than the power consumption after the regenerative power generation section. The vehicle power generation control device according to 1 or 2.   The regenerative power generation information predicting unit predicts the regenerative power generation section by predicting a fuel cut start point and a duration of the fuel cut based on road map information of the navigation system. The vehicle power generation control device according to any one of 1 to 3. The road map information of the navigation system includes road gradient information,
The regenerative power generation information predicting means predicts the regenerative power generation section by predicting the fuel cut start point and the duration of the fuel cut based on the road gradient information and vehicle speed information. The vehicle power generation control device according to claim 4.   6. The vehicular power generation control device according to claim 5, wherein the road gradient information is set for each point where the road gradient changes. The road gradient information consists of the road elevation set for each point where the road gradient changes and the distance information between the points.
The regenerative power generation information predicting means calculates a road gradient based on the altitude difference between the points and the distance between the points, and the fuel cut start point and its fuel based on the road gradient and vehicle speed information. The vehicle power generation control device according to any one of claims 4 to 6, wherein the regenerative power generation section is predicted by predicting a duration of cut.

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