Abstract:
Disclosed herein is a system for assisting fuel-efficient driving, which can advise a driver to perform fuel-efficient driving by displaying a current fuel economy corresponding to a current driving state on a graph such that a driver can compare the current driving state with a target driving state for achieving an optimum fuel economy of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims under 35 U.S.C. §119(a) priority to Korean Application No. 10-2007-0133186, filed on Dec. 18, 2007, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a system for assisting fuel-efficient driving that assists a driver in achieving optimum fuel economy while driving a vehicle. 
     2. Related Art 
     Due to the rise in oil prices and environmental concerns, vehicle manufacturers have conducted intensive researches to improve fuel efficiency of vehicles. Vehicle fuel efficiency depends not only on vehicle engine and transmission tuning technologies but also drivers&#39; driving habits, such as a rapid deceleration habit or a rapid braking habit. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     The present invention provides a system for assisting fuel-efficient driving that can advise a driver to perform fuel-efficient driving by displaying a current fuel economy corresponding to a current driving state on a graph such that a driver can compare the current driving state with a target driving state for achieving an optimum fuel economy of the vehicle. 
     In accordance with a preferred embodiment of the present invention, the present invention provides a system for assisting fuel-efficient driving, including: a collection unit for collecting driving state information of a vehicle; a storage unit for storing a fuel consumption map over a variety of driving conditions, wherein the fuel consumption map classifies the driving conditions into several groups depending on fuel consumption levels thereof; and a calculation unit for calculating a current fuel consumption level and a target driving condition for achieving an optimal fuel consumption level of the vehicle, based on the information from the collection unit and the fuel consumption map; and a display control unit for graphically displaying the current fuel consumption level and the optimal fuel consumption level on a display such that a driver can compare the current fuel consumption level with the optimal fuel consumption level so as to pursue the target driving condition. 
     The groups may comprise a low fuel consumption range, a moderate fuel consumption range and a high fuel consumption range. The fuel consumption ranges may be visualized as a graph on the display such that fuel consumption levels in the fuel consumption ranges can be compared with each other. The current fuel consumption level may be displayed on the graph as a pointer and the pointer may move in accordance with changes of the current fuel consumption level responding to acceleration changes of the vehicle. 
     Regions or width of the fuel consumption ranges in the graph may be changed depending on the current driving state. 
     The display control unit may further display a current fuel consumption range where the current fuel consumption level is among the fuel consumption ranges. 
     The calculation unit may periodically store the current fuel consumption range while the driver drives the vehicle and makes a statistical data for the stored current fuel consumption ranges. The display control unit may operate to display this statistical data on the display upon demand from the driver. 
     The calculation unit may periodically store a current vehicle speed while the driver drives the vehicle and makes a statistical data for the stored current vehicle speeds. The display control unit may operate to display this statistical data on the display upon demand from the driver. 
     The display control unit may further display whether or not fuel is cut. 
     The driving state information collected by the collection unit may comprise at least one of a vehicle speed, a brake pedal position value, a TPS value, a transmission gear position, a engine RPM, and whether or not fuel is cut. 
     It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
     The above and other features of the invention are discussed infra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of a system for assisting fuel-efficient driving according to an embodiment of the present invention; 
         FIG. 2  is a view showing an example of economical driving information displayed according to the present invention; 
         FIG. 3  is a view showing another example of economical driving information displayed according to the present invention; 
         FIG. 4  is a flowchart of the operation of a system for assisting fuel-efficient according to an embodiment of the present invention; and 
         FIGS. 5A and 5B  are flowcharts of the operation of a system for assisting fuel-efficient according to an embodiment of the present invention, respectively. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, systems for assisting fuel-efficient driving according to preferred embodiments of the present invention will be described in detail with reference to the attached drawings. 
     In an embodiment, as shown in  FIG. 1 , a system for assisting fuel-efficient driving includes a collection unit  10 , a storage unit  20 , a calculation unit  30  and a display control unit  40 . 
     The collection unit  10  collects information about current driving state of a vehicle using an engine control unit (ECU), a transmission control unit (TCU), a vehicle speed sensor, a throttle position sensor (TPS) and a brake position sensor (BPS), etc. In particular, information about an engine RPM and whether fuel is cut or not is transmitted from the engine control unit to the collection unit  10 , and information about a transmission gear position and whether a damper clutch is in an ON or OFF position is transmitted from the transmission control unit to the collection unit  10 . 
     The storage unit  20  stores therein a fuel consumption map which has data regarding fuel consumption levels over a variety of driving conditions. The fuel consumption map classifies the driving conditions into several groups depending on fuel consumption levels of the driving conditions. The groups comprise a low fuel consumption range, a moderate fuel consumption range and a high fuel consumption range (more details will be described hereafter). Meanwhile, the fuel consumption map can be made based on an engine map or a shift pattern map. The fuel consumption map based on the engine map is now quite well known in this art. With regard to the fuel consumption map based on the shift pattern map, Korean Patent Application No. 2007-0129233 (not published) or other known techniques can be referenced. 
     The calculation unit calculates a current instantaneous fuel consumption level and a target driving condition for achieving optimal fuel consumption level of the vehicle, based on the information from the collection unit  10  and the fuel consumption map during driving. Also, the calculation unit periodically stores data for a current fuel consumption range and for a current vehicle speed, and statistical data of the stored current fuel consumption ranges and vehicle speeds is displayed by the display control unit  40  (refer to  FIG. 3 ). 
     The display control unit  40  graphically displays the current fuel consumption level and the optimal fuel consumption level on a display such that a driver can compare the current fuel consumption level with the optimal fuel consumption level so as to pursue the target driving condition. Further, the display control unit  40  may display the fuel consumption ranges in various ways as long as fuel consumption levels in the fuel consumption ranges can be compared with each other. For example, the display control unit  40  may display the fuel consumption ranges as a bar graph  41  on the display such that fuel consumption levels in the fuel consumption ranges can be compared with each other, wherein the current fuel consumption level is displayed on the bar graph  41  as a pointer  42  and the pointer  42  moves in accordance with changes of the current fuel consumption level responding to acceleration changes of the vehicle. The indication of the current fuel consumption level on the bar graph  41  allows the driver to know where the current driving state is among the low fuel consumption range, moderate fuel consumption range, and high fuel consumption range, and to immediately perceive deviation degree of the current driving state from the target (optimal) driving condition. 
     Referring to  FIGS. 2 and 3 , information displayed on the display will is explained below. 
     As shown in  FIG. 2 , the low fuel consumption range, the moderate fuel consumption range and the high fuel consumption range are displayed on the display as a bar graph  41 . The low fuel consumption range (e.g., green) is positioned in a center portion of the bar graph  41 . The moderate fuel consumption range (e.g., yellow) and the high fuel consumption range (e.g., orange) are disposed on each of left and right sides of the low fuel consumption range in consideration of positive/negative acceleration of the vehicle. The left side from the low fuel consumption range is for negative acceleration (deceleration) and the right side from the low fuel consumption range is for positive acceleration of the vehicle. 
     The current fuel consumption level is indicated by the pointer  42  on the bar graph  41 . In the case where the driver rapidly accelerates the vehicle more than the current driving state shown in  FIG. 2 , the pointer  42  moves in the right direction to the moderate fuel consumption range, even to the high fuel consumption range, from the current low fuel consumption range. In contrast, in the case where the vehicle rapidly decelerates, the pointer  42  moves in the left direction to moderate fuel consumption range, even to high fuel consumption range. The driver can, instinctively, discern the current fuel consumption level and adjust the extent to which a brake or accelerator pedal is pressed in order to achieve the optimal fuel consumption level. 
     Meanwhile, each region, more concretely, referring to  FIG. 2 , each width of the fuel consumption ranges can vary depending on the current driving state. In the case where a current acceleration rate of the vehicle is extremely high, the pointer  42  moves to far end of the high fuel consumption range. In that case, the width of the high fuel consumption range at the right side of the low fuel consumption range can be increased and the width of the low fuel consumption range can be decreased relatively. Variation of the width of the fuel consumption ranges allows the driver to perceive the current driving state of the vehicle more clearly and to pursue the optimal target driving condition more actively watching the bar graph  41  on the display. 
     Still referring to  FIG. 2 , a consumption range indicator  43 , a fuel cut indicator  44 , or both may be provided on the display. The consumption range indicator  43  shows the current fuel consumption range where the pointer  42  is among the fuel consumption ranges. The driver can easily discern the current driving state. Whether fuel is cut or not is an important factor in improving fuel economy of the vehicle, and it is thus separately displayed on the display. For example, when the vehicle travels downhill, it is recommended to use inertia and gravity rather pressing the accelerator pedal. The fuel cut indicator  44  assists the driver to take his/her foot off accelerator pedal when it is helpful for fuel economy. 
     A detailed driving information button  45  may be provided on the display as shown in  FIG. 2 . In this case, a touch screen is used for the display. When the detailed driving information button  45  is pushed, as shown in  FIG. 3 , detailed driving information is displayed on another window of the display. The detailed driving information comprises distribution chart of fuel consumption which is displayed on a display part for statistical data of fuel consumption  46 , and distribution chart of vehicle speed which is displayed on a display part for statistical data of vehicle speed  47 . For example, if the detailed driving information, shown in  FIG. 3 , is results cumulated for one day, it is to be understood that the driver drives in the low fuel consumption range for 45% and vehicle speed from 60 to 90 km/h for 35% of the whole driving time. Using this information, the driver can check his/her driving habits and pursue more economical driving habit. 
     An operation example of the system for assisting fuel-efficient driving will be described with reference to  FIGS. 2 and 4 . 
     When ignition is turned on and the vehicle moves, the system starts to collect driving state information and calculates the current instantaneous fuel consumption level and the optimal fuel consumption level to be achieved. And, the system displays on the display the bar graph  41  in which the low/moderate/high fuel consumption ranges are visualized (for instance, they may be visualized in different colors, e.g., green, yellow and orange, respectively). The center portion of the low fuel consumption range corresponds to the target driving condition ensuring the optimal fuel consumption level. The current instantaneous fuel consumption level is indicated by the pointer  42  on the bar graph, and the current fuel consumption range indicator and the fuel cut indicator  44  are also displayed on the display. And, when the ignition is turned off, the system stops its operation. 
     Another operation example of the system for assisting fuel-efficient driving will be described with reference to  FIGS. 3 ,  5 A and  5 B. 
     As shown in  FIGS. 3 and 5A , when the ignition is turned on, the system initializes data during previous operation. Temporary data only which is used while driving is initialized when newly the ignition is turned on, daily data which is accumulated and analyzed for one day is initialized when date is changed and data optionally accumulated by driver&#39;s selection is initialized when an initialization button is activated. 
     After the initialization, the system collects driving state information, calculates the current fuel consumption level of the vehicle. And then, the system calculates or determines the current fuel consumption range and stores the result data periodically, for example, every second. Based on the result data, the system makes statistical data for the stored current fuel consumption ranges and displays a distribution chart of fuel consumption on the display upon demand by the driver. 
     As shown in  FIGS. 3 and 5B , when the ignition is turned on, the system initializes data during previous operation as mentioned above. After the initialization, the system collects current vehicle speed and stores data for the current vehicle speed periodically, for example, every second. Based on data, the system makes statistical data for the stored current vehicle speeds and displays a distribution chart of vehicle speed on the display upon demand by the driver. 
     As described above, in the system for assisting fuel-efficient driving according to the present invention, the current fuel consumption level and the current fuel consumption range are displayed so that a driver can compare them to each other. Furthermore, the system provides other various information related to fuel consumption of the vehicle with the driver, thereby enabling the driver to keep an economical driving habit. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.