Compact ev system

Abstract

To solve a problem of smaller battery capacity that is the biggest challenge to a widespread use of electric vehicles as a measure against global warming, resulting reduction in driving range, lack of charging points to ensure sufficient driving range, and complicated charging, to promote a spread of electric vehicles.SOLUTION: A vehicle travels from a starting point to a destination by making maximum use of a battery charge power stored in a normal charging device installed in a home parking lot, etc. However, if there is insufficient battery charge power to travel from the starting point to the destination, the insufficient power is covered by energy-saving driving of the vehicle, and if there is still a shortage, the vehicle continues to travel by recharging a minimum amount of power at optimal charging spots along a travel route.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a small electric vehicle that is equipped with a relatively small capacity battery, which is charged using a normal charging device installed at the vehicle owner's parking space at their home, and that makes maximum use of the battery's charging power for driving the vehicle.If there is a risk of a battery power shortage while driving before reaching the destination, the battery charging power is used effectively and efficiently through energy-saving driving, and further, if necessary to reach the destination, the minimum amount of power that is expected to be insufficient is replenished at charging spots along the way, thereby extending the vehicle's range. [Background technology]

[0002] The main purpose of converting vehicles to electric vehicles is to reduce CO2 emissions as a measure against global warming. However, in order to ensure a certain driving range, the battery capacity must be increased, which results in a heavy vehicle and a high vehicle price, and the CO2 reduction effect is not as great as expected. As a result, the spread of electric vehicles in Japan has been significantly delayed. To solve this problem, it is necessary to make the battery capacity as small as possible in accordance with the intended use of the vehicle, to charge the battery simply and effectively, and to make efficient use of the charging power.

[0003] Specific measures to address the shortened vehicle range caused by reducing the capacity of batteries in current vehicle configurations include expanding charging spots, energy-saving driving by regenerative braking or coasting to a target deceleration / stop point, reducing running resistance by reducing the running speed or vehicle weight, or using plug-in hybrids, but these individual measures alone are insufficient or inappropriate for the widespread use of small EVs (Patent Document 1, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2018-046735 [Patent Document 2] Patent Publication No. 2019-054726 [Patent Document 3] Patent Publication No. 2021-088361 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to promote the spread of small EVs by substantially resolving or alleviating the biggest problems in the spread of small electric vehicles, namely, insufficient driving range due to relatively small capacity batteries and the hassle of battery charging. [Means for solving the problem]

[0006] As a measure to resolve the above issues, we first consider simplifying battery charging in preparation for the start of a journey, formulating a rational driving plan using charged power from the vehicle's starting point to its destination, and efficiently and effectively utilizing, managing, and replenishing battery charging power under corresponding actual driving conditions. In principle, charging of the battery prior to starting driving is carried out using a normal charging device installed in the vehicle owner's home parking space or the like. The main use of the vehicle is for driving in urban areas. Therefore, it is assumed that the vehicle has a battery capacity of 10 to 15 kWh, which is capable of driving on a full charge, including the average daily driving distance of small vehicles in Japan (for example, 70 km) plus the power consumption of auxiliary equipment such as air conditioning and lighting while driving, and that the battery can be charged normally, preferably using renewable energy, while the vehicle is parked at home, etc., for 8 to 10 hours at night, etc.

[0007] As shown in FIG. 1, before starting a journey from the starting point, the vehicle searches for a route to the destination point of the day, and calculates the distance Do between the starting point and the destination point based on the battery full charge power (Ebf- It is determined whether it is possible with Ebm), and if it is possible, that is, if the driving distance Do is less than or equal to the cruising distance Dc, normal driving to the destination is performed with the battery fully charged power. If it is impossible, that is, Dc < Do (where Dc: cruising distance when the battery is fully charged), energy-saving driving is started. Here, energy-saving driving means energy-saving driving as a result of reducing air resistance by reducing the constant-speed driving speed (from vc to vc') during normal driving corresponding to the vehicle driving purpose, or energy-saving deceleration driving mainly by inertial driving toward the target deceleration / stop points such as intersections on the driving route. Here, for example, in the case of the normal constant-speed driving speed vc = 60 km / h, the decelerated constant-speed driving speed vc' = 50 km / h, and deceleration driving by inertial driving, the energy-saving effect coefficient α is α ≒ 0.2. That is, this energy-saving driving enables an extension of the cruising distance by about 1.2 times compared to normal driving. If it is assumed that the reduction in battery power consumption as a result of this energy-saving driving is still insufficient to reach the destination, the shortage is replenished with the minimum necessary amount at the charging spots during the driving route to reach the destination. As a result, the battery charging frequency and charging power amount during the driving route can be reduced. Here, in principle, the battery power consumption per unit driving distance is calculated from the battery power consumption record based on the actual driving results including the current day.

Effect of the Invention

[0008] As a result, the vehicle can drive to the destination with the battery charging power Ebt at the current time and location, that is, when the battery charging power Edt required for driving from the current location to the destination is considered, if Ebt > Edt, it will drive normally towards the destination. However, if it is determined that it is impossible to travel to the destination with the battery charging power Ebt, i.e., Ebt < Edt, perform energy-saving driving at regular intervals ΔD corresponding to the driving state of the vehicle. (If the battery power at the end of the energy-saving driving for a certain distance ΔD meets the power required for traveling to the destination, it is possible to stop the energy-saving driving as subsequent energy-saving driving for traveling to the destination is unnecessary. However,) if the battery power Ebt is less than Edt with respect to the power Edt required for traveling to the destination point, at the time and location where it is determined that Ebt < Edt, when it becomes possible to replenish the insufficient power shown by R in FIG. 1 to the battery, access the charging spot on the travel route to the destination point from that time and location and charge the minimum power required for traveling from that point to the destination and then travel to the destination. That is, in an electric vehicle having a small-capacity battery, even when the battery power is insufficient for energy-saving driving to the destination point, it is possible to travel to the destination point by replenishing at the charging spot at the time and location where it is possible to replenish the minimum power required for traveling to the destination point.

Brief Description of the Drawings

[0009] [Figure 1] The battery power vs. travel distance characteristics showing the relationship between battery power and travel distance according to the present invention, including the case of normal driving, the case of energy-saving driving, and the supplementary charging method when it is impossible to reach the destination even with energy-saving driving. [Diagram 2] It is an explanatory diagram of the battery charging power and vehicle drive control concept according to the present invention.

Embodiments for Carrying Out the Invention

[0010] To implement the present invention, it is necessary to partially improve the car navigation device installed in the vehicle. Specifically, it is necessary that the map database built into the device has data on the locations of charging spots for the electric vehicle, charging capacity, etc., a function to grasp the battery status, and characteristics of the vehicle's mileage including battery power consumption and auxiliary equipment consumption such as air conditioner and lighting. Here, with regard to the battery power consumption and vehicle mileage characteristics, it would be effective to use the most recent past records including the current day of the vehicle. EXAMPLES

[0011] FIG. 2 shows a conceptual diagram of vehicle drive control when the distance between the departure point and destination is within the cruising range Dc or within twice the cruising range. In FIG. 201 is a control start point in the example of the driving control procedure for a small EV according to the present invention; 202 is a full charge state determination process for determining whether the charging power of the battery mounted on the vehicle is in a full charge state; 203 is a full charge process for charging the battery to full charge if it is determined in process 202 that the battery is not fully charged; 204 is a route search process for identifying a route distance from a starting point of the vehicle to a destination point, and identifying target deceleration / stopping points and charging spots along the route; 205 is a process for determining the current battery power Ebt and the power Edt required for normal driving from the current point to the destination point on the route determined in the process 204, or the power Ed't required for energy-saving driving; 206 is a process for determining whether or not driving to the destination point is possible with the current battery power Ebt; 207 is a normal driving process for performing normal driving of a certain distance ΔD when it is determined in the process 206 that driving to the destination with the battery power Ebt is possible (i.e., Ebt>Edt); 208 is a destination point arrival determination process for determining whether the current point is the destination point as a result of the process 207;

[0012] 209 is a destination reachability determination process for determining whether or not the destination can be reached by energy-saving driving when it is determined in the process 206 that the drive from the current point to the destination point is impossible by normal driving. 210 is an energy-saving driving process for driving in an energy-saving manner for a certain distance ΔD from the current point; 211 is a current location and current battery power determination process that determines the result of the process 210, the current location, the distance Ed't from the destination point, and the current battery power Ebt; 212 is a power supply availability determination process for determining whether or not the battery can be charged with the power required to reach the destination when it is determined that the destination cannot be reached with the current battery power as a result of the process 209; 213 is a charging spot identification process for identifying a charging spot on the route from the current point to the destination point when it is determined that supplementary charging is possible as a result of the process 212; 214 is a charging spot access / charging process for accessing the charging spot identified in process 213 and charging the electric power required for traveling from the current point to the destination point; 215 is an Ebt·Ed't determination process for determining the current battery power Ebt as a result of the process 214 and the required power Ed't for the destination point; 216 is a destination arrival determination process 1 that determines whether the vehicle has reached the destination based on the result of the process 208; 217 is a destination point arrival determination process 2 for determining whether or not the destination point has been reached based on the result of the process 211; Reference numeral 218 denotes an EV drive control process end point at which this series of control processes ends if it is determined as a result of process 217 and process 212 that the current location is the destination point. [Industrial Applicability]

[0013] By configuring and controlling as described above, if the battery charge power at the starting point is sufficient to travel from the starting point to the destination, the vehicle will use battery power, and even if the battery power is insufficient, the vehicle will perform necessary energy-saving driving, and if the destination cannot be reached even with energy-saving driving, the estimated shortfall will be charged at an appropriate charging spot along the way, that is, the vehicle will be able to travel to the destination by charging the minimum amount of power required at the optimal charging spot where the shortfall can be charged.In other words, the problem of insufficient driving range can be solved and reduced by charging the vehicle when not in use at the vehicle owner's home parking lot, energy-saving driving using the charging power, and charging the minimum amount of power required to reach the destination at charging spots along the way.

[0014] Although the main target of the present invention is small EVs in the above, it is not necessarily limited to this. It can also be applied to medium and large vehicles by optimizing the selection of charging spots including charging capacity to suit the charging form of the vehicle. [Explanation of symbols]

[0015] Eb: Battery charging power Ebf: Battery full charge power Ebo: Minimum battery charging power Ebt: Current battery power Ed: Battery power required to travel from the starting point to the destination Edt: Battery power required for normal driving from current point to destination point Ed't: The amount of battery power required for energy-saving driving from the current point to the destination point, installed in the home parking lot, etc. D: Vehicle mileage Dc: Driving range (distance that can be traveled with a fully charged battery (Ebf-Ebm)) Do: Distance between starting point and destination point Dt: Distance between the vehicle's current location and the destination ΔD: unit (constant) distance traveled α: Energy saving driving effect coefficient

Claims

[Claim 1] The vehicle is equipped with a battery having a capacity capable of storing a sufficient amount of power to drive the vehicle for an average daily driving distance, and the battery can basically be charged by normal charging for a certain period of time (e.g., 8 hours) or less at a parking place such as the vehicle's home. Prior to starting driving, a route and distance search is performed, including the driving distance from the starting point to the destination and the target deceleration and stopping point, the location of the charging spot and charging capacity, and the amount of charging power to the vehicle's onboard battery are identified, and it is determined whether normal driving from the starting point to the destination with the charged power is possible, and if so, normal driving toward the destination is performed. If it is expected that normal driving with battery charging power will be insufficient to travel to the destination, energy-saving driving will be performed while periodically identifying the remaining battery power and the remaining distance from the current point to the destination for every certain distance traveled ΔD. If it is expected that supplemental charging of the remaining battery power will be necessary during this energy-saving driving, the amount of power required for energy-saving driving to cover the remaining distance to the destination is identified, and the charging timing and location at a charging spot where this charging is possible is identified, and the identified charging spot is accessed to supplement the required amount of power. This compact EV system is characterized by managing the battery power including charging as described above, managing the distance to the destination, and controlling driving accordingly, enabling normal or energy-saving driving from the starting point to the destination. Here, energy-saving driving refers to driving that extends the distance that can be traveled by reducing the running resistance through constant speed driving at a speed vc' that is a fixed percentage lower than the normal running speed vc, and by decelerating mainly by coasting to a target deceleration / stopping point such as an intersection.

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