SE527951C2 - Monitoring system for time spent by vehicle in city traffic situation, used for fleet management, compares difference in distance travelled by left and right front wheels - Google Patents

Abstract

A speedometer (310) is used to record a vehicle speed (v) and a comparator (320) is used to compare the recorded speed with a threshold speed (vCITY). If at a given time (t 0) the recorded speed is less than the threshold speed then a traffic situation classification unit (330) is used to calculate a left wheel path (SL) covered by the left front wheel (210) of the vehicle over a measurement period (T) after the given time (t 0), calculate a right wheel path (SR) covered by the right front wheel (211) of the vehicle over the same measurement period (T) and calculate the difference between these two distances. If the difference exceeds a threshold value (SCITY) then at least measurement period (T) is defined as an interval (ICITY) during which the vehicle has encountered a city traffic situation.

Description

20 25 30 527 951 driving time, an idle time, a mileage, a road speed - instantaneous or average, a total fuel consumption, a current fuel consumption - instantaneous or average, a fuel rate - instantaneous or average, a coolant temperature - instantaneous or average, an oil pressure - instantaneous or average, an engine speed - instantaneous or average, a turbocharged pressure - instantaneous or average, a number of decelerations, and a number of hard decelerations. The registered parameters can be transferred to a central node, for example a Fleet Management Portal (FMP) for generating different types of reports and other types of analysis data. Thus, hauliers can compare the behaviors of different drivers and the conditions that the vehicles in their fleet go through.

However, the parameters monitored by the known on-board log modules do not provide a sufficient basis for fully understanding all the factors affecting the vehicles and determining the important effects that result therefrom. For example, differences between different vehicles in terms of fuel consumption, wear and total service life are believed to depend on the proportion of driving that takes place in city traffic.

SUMMARY OF THE INVENTION The object of the present invention is therefore to provide a solution which alleviates the above problems, and thus to offer a reliable automatic measurement of the proportion of a run which has been carried out under city traffic conditions.

According to one aspect of the invention, the object of an arrangement for determining an urban traffic situation is achieved by reviewing a wheeled motor vehicle, which includes a speedometer, a comparator and a traffic situation classification unit.

The speedometer is adapted to register a vehicle speed. The comparator is adapted to compare the vehicle speed with a threshold speed. The traffic situation classification unit 10 15 20 25 30 527 951 is adapted to, if, at a time to, the vehicle speed falls below the threshold speed, determine a left-wheel drive distance traveled by the left front wheel during a measuring period after the time to. The traffic situation classification unit is also adapted to determine a right-wheel drive distance traveled by the right-hand front wheel during the measurement period. Then the traffic situation classification unit determines a distance difference between the left-wheel drive and the right-wheel drive, and if the absolute value of the distance difference exceeds a threshold distance, at least the measurement period is defined as an interval during which the vehicle has undergone a city traffic situation.

An important advantage achieved by this arrangement is that a reliable measure of the proportion of a run that has been performed under city traffic conditions can be obtained in a very processing-efficient manner. In addition, the traffic situation can be expressed both in terms of time and distance. This allows a great deal of freedom with regard to how the said city driving share is defined.

According to an embodiment of this aspect of the invention, the traffic situation classification unit is adapted to define the interval during which the vehicle undergoes the city traffic situation from to to a time after two when the vehicle speed for the first time becomes equal to, or exceeds, the threshold speed.

This defines a simple and unambiguous final criterion for the traffic situation interval. According to another embodiment of this aspect of the invention, the traffic situation classification unit is adapted to, after two, determine the distance difference between the left and right wheel distances on repeated measuring occasions in a sliding window, which has an extension in time equal to the measuring period.

Thus, a certain wheelbase (at least in part) can be included in several difference calculations. As a result, very accurate and fast measurement results can be achieved.

According to yet another embodiment of this aspect of the invention, the traffic situation classification unit is adapted to, after two, determine the distance difference between the left and right wheel distances at repeated measurement occasions, where two consecutive measurement occasions are separated by at least one interval which is at least one interval. equivalent to the measurement period. Consequently, the distance difference calculations become less processing-intensive. Still, the result is reliable.

According to yet another embodiment of this aspect of the invention, the traffic situation classification unit is adapted to interrupt the interval during which the vehicle undergoes the city traffic situation if, over a control distance traveled by the vehicle after time two, the absolute value of the distance difference has not exceeded the threshold. measuring occasions. This defines an alternative final criterion for the traffic situation interval, which can be useful if the vehicle leaves the urban environment without increasing its speed above the threshold speed. According to yet another embodiment of this aspect of the invention, the arrangement comprises means which are adapted to register a respective wheel speed for the left and right front wheels during the measuring period. In addition, the traffic situation classification unit is adapted to determine the left and right wheel distances based on these wheel speeds. This is an advantageous way of determining wheel distances as specific wheel speedometers are often integrated in modern braking systems, such as anti-lock braking systems (ABS), traction control systems (TCS) and electric braking systems (electric braking systems). Electronic Braking System - EBS).

According to another aspect of the invention, the object is achieved by a wheeled motor vehicle, which includes the arrangement proposed above. Of course, such a vehicle is advantageous for the same reasons as the arrangement itself. According to another aspect of the invention, the object is achieved by a method for determining a city traffic situation passed through a wheeled motor vehicle, which comprises the steps of: recording a vehicle speed; comparing the vehicle speed with a threshold speed, and if at a time to, the speed falls below the threshold speed; determining a left wheel distance traveled by the left front wheel during a measurement period after the time to; determining a right wheel distance traveled by the right front wheel during the measurement period; determining a distance difference between the left and right wheel distances, and if the absolute value of the distance difference exceeds a threshold distance; definition of at least the measurement period as an interval during which the said vehicle has undergone a city traffic situation. If, at any time, a speed is registered which is equal to or exceeds the threshold speed, the interval during which said vehicle undergoes a city traffic situation is interrupted. This is desirable, since thus a reliable measure can be obtained of the proportion of a run that has been performed under city traffic conditions. In addition, the traffic situation can be expressed in both time and distance, so that a great deal of freedom is offered with regard to how the said share is to be defined.

According to an embodiment of this aspect of the invention, the object is achieved by defining the interval during which the vehicle undergoes the city traffic situation from two to a time after two when the speed for the first time becomes equal to, or exceeds, the threshold speed. This defines a simple and unambiguous final criterion for the traffic situation interval.

According to another embodiment of this aspect of the invention, the object is achieved by, after two, determining the distance difference between the left and right wheel distances on repeated measuring occasions. This is done either in a sliding measurement window, which has an extension in time equal to the measurement period, or in repeated measurement occasions, where two consecutive measurement occasions are separated by at least an interval that is equivalent to the measurement period. In all cases, the interval during which the vehicle undergoes the city traffic situation is interrupted if, over a control distance traveled by the vehicle after time two, the absolute value of the distance difference has not exceeded the threshold distance at any of the said measurement occasions.

This defines an alternative final criterion for the traffic situation interval. This criterion can be met if, for example, the vehicle leaves the urban environment without increasing its speed above the threshold speed.

According to a further aspect of the invention, the object is achieved by a computer program directly downloadable to the internal memory of a computer, comprising software for controlling the method proposed above when said program is run on a computer.

According to another aspect of the invention, the object is achieved by a computer-readable medium having a stored program, the program being adapted to cause a computer to control the method proposed above.

Thus, the invention provides a solid basis for determining the amount of driving of a particular vehicle that has been undergone in a city traffic environment. The proposed solution is thus particularly well suited for heavy vehicle applications, where it is important to understand any differences between vehicles in terms of fuel consumption, wear and overall service life. Based on a figure that reflects such a share, it is in turn possible to analyze how a certain haulier uses the vehicles in its fleet, and thereby assist in selecting suitable future vehicles, or propose modifications to existing vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail with the aid of embodiments, which are described by way of example, and with reference to the accompanying drawings.

Figures 1a, 1b show timelines illustrating how city traffic intervals can be defined according to an embodiment of the invention, Figure 2 shows how a distance difference is calculated according to an embodiment of the invention, Figure 3 shows a motor vehicle comprising an arrangement according to an embodiment of the invention, and Figure 4 shows a flow chart illustrating the general method of the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION A timeline is shown in Figure 1a, which illustrates how a city traffic interval 1cm can be defined for a vehicle according to an embodiment of the invention. The diagram represents a completed city traffic situation with a first state 1, and a non-city traffic situation with a second state 0.

The vehicle's speed v is registered, and at a time to, it is assumed that the speed v is less than a threshold speed vcm, say 60 km / h. During a measuring period T (say 1 to 30 seconds) after the time to, a left-wheel drive distance is determined, which is traveled by the left-hand front wheel. Correspondingly, during the measurement period T, a right-wheel drive distance determined by the vehicle's right front wheel is also determined.

Then, at the end of the measurement period T, ie at t = t0 + T, a distance difference between the left-wheel drive and the right-wheel drive is determined. If the absolute value of the distance difference exceeds a threshold distance, the vehicle is assumed to have made a relatively sharp turn, and since the speed is relatively low, the vehicle is in a city or comparable driving environment. Therefore, at least the measurement period T is defined as an interval lcm during which the vehicle has undergone a city traffic situation.

According to an embodiment of the invention, a period following t = t0 + T is also assumed to represent a period during which the vehicle undergoes a city traffic situation. In fact, the urban traffic situation continues until a vehicle speed v i is recorded, which is equal to or exceeds the threshold speed who. Then, that is, here at t = t0 + t ,,, the interval Iwy is interrupted during which the vehicle undergoes the city traffic situation.

According to another embodiment of the invention, the city traffic interval 1 cm can be interrupted even if an alternative criterion is met. This will be discussed below with reference to Figure 1b.

In Figure 1b, at t = t0 + ty, the vehicle speed v is below the threshold speed vem. In addition, we assume that the above-mentioned distance difference criterion is met. Thus, a new city traffic interval lcm begins at t = t0 + t ,. After this time, a distance difference between the left-wheel section and the right-wheel section is determined on repeated measurement occasions.

According to a first embodiment of the invention, the distance difference is determined in a sliding measuring window, which has an extension in time equal to the measuring period T. The sliding measuring window involves that, at a measuring time ti, the distance difference is determined during a previous period from t = ti-T to t = ti. Correspondingly, the distance difference at a later time point ti + ti is determined during a previous period from t = t, + t; -T to t = t, + t¿, etc. Thus, if, for example, ti + tj is less than T from t, (in other words t, - is included in both distance difference calculations.

According to a second embodiment of the invention, instead the difference in distance is determined on repeated measuring occasions, where two consecutive measuring occasions are separated by at least one interval equivalent to the measuring period T. Consequently, with reference to the example above, tjzT, so that no measuring intervals The new city traffic interval lcm, continues until a sufficiently small proportion of sharp turns have been registered. This criterion is repeatedly tested by determining the distance difference according to one of the above two embodiments, and if, over a control travel distance snMEooT traveled by the vehicle after the time t = to + ty (when the speed v was below the threshold speed vom ), the absolute value of the distance difference has not exceeded the threshold distance at any of the mentioned measurement occasions. Under typical conditions, the control distance s-.MEQUT can be selected to about 1 km. In principle, however, any other distance is conceivable.

According to an embodiment of the invention, the control travel distance sfooooof is defined as the distance which is traveled by the vehicle during a period extending from the time t = to + ty to a certain later time t = to + t ,.

Figure 2 illustrates how a distance difference between the left and right wheel distances sL and sR is determined according to an embodiment of the invention.

The figure schematically shows a pair of front wheels 210 and 211, which move together with a vehicle with a speed v. At a time to, the speed v is less than the threshold speed vom.

Therefore, starting at to, a left wheel distance sj is measured, which is traveled by the left front wheel 210 during a measuring period T. During the same measuring period T, a right wheel distance so is measured, which is traveled by the right front wheel 211. Then, after the measuring period T (say 1- 30 s), a distance difference between the left-wheel section sj and the right-wheel section sk. If the absolute value of the distance difference, ie | s, _ - sR |, exceeds a threshold distance defined by the beginning of a city traffic interval loj-fy. Of course, the threshold distance depends on the measuring period T, so that a relatively long measuring period T requires a relatively long threshold distance such as, and vice versa.

The urban traffic interval iom, is defined to extend at least during the measurement period T. However, according to one embodiment of the invention, the interval iom is defined from to to a time after the vehicle speed v for the first time equals, or exceeds, the threshold speed who, (see Figure 1).

According to another embodiment of the invention, the left and right wheel distances sL and sR are measured by means of a respective speedometer 210a and 211a associated with the left and right wheels 210 and 211. Typically, each speedometer 210a and 211a generates an instantaneous angular velocity value, and based on these values, a conversion from speed to distance can be performed by integrating the speed over the measurement period T. For example, a traffic situation classification unit (see below with reference to figure 3) can be adapted to perform this task.

Figure 3 shows a wheeled motor vehicle 300 which includes an arrangement according to an embodiment of the invention. The proposed arrangement includes a speedometer 310, a comparator 320 and a traffic situation classification unit 330.

The traffic situation classification unit 330 in turn includes a computer readable medium 335, which stores a program adapted to cause a computer in the unit 330 to perform the above-mentioned traffic situation classification method.

The speedometer 310 can collect data from the speedometers 210a and 211a, and on this basis derive a vehicle speed v. However, an alternative speedometer, for example a separate meter for recording an engine speed parameter, is equally conceivable. The comparator 320 is adapted to compare the registered vehicle speed v with the threshold speed vcm, and the traffic situation classification unit 330 is adapted to distinguish a city traffic situation from a non-city traffic situation according to the above strategy, and thus define one or more city traffic interval 300 below it. .

For the purpose of summarizing, the general method according to the invention will now be described below with reference to the flow chart in Figure 4.

A first step 410 registers a vehicle speed v. Then a step 420 compares the speed v with a threshold speed vcm, and if the speed v is equal to or higher than the threshold speed vcm, the procedure returns to step 410. Otherwise, a step 430 measures a left wheel distance sL and a right-wheel distance sR which is traveled by the left-hand front wheel and the right-hand front wheel, respectively, during a measurement period T after the time tg.

Then, a step 440 determines a distance difference between the left wheel distance s | _ and the right wheel distance sR, and checks whether the absolute value of the distance difference exceeds a threshold distance scm. If so, a step 450 follows. Otherwise, the procedure returns to step 410.

Step 450 starts a city traffic interval lCm, ie a period during which the vehicle is defined to undergo a city traffic situation. However, the city traffic interval 1cm extends at least over the measurement period T. According to what has been discussed above, the interval 1cm preferably extends further. Steps 470 and 480 determine the end point of the interval lcm.

A step 460 after step 450 again registers the vehicle speed v, and step 470 checks whether the speed v is equal to or exceeds the threshold speed v. If the speed v is equal to or exceeds the threshold speed vcm, the procedure proceeds to a step 490. Otherwise, step 480 follows, which examines whether, over a control distance smnßouf traveled by the vehicle after the time when the speed v first fell below the threshold speed vom, the absolute value of distance - “the difference (i.e. | sL - sR |) has exceeded the threshold distance scm at any of the repeated measurement occasions (as described above with reference to Figure 2). Thus, step 480 involves substantially repeated executions of steps 430 and 440.

Step 490 terminates the city traffic interval lcm after one of the final criteria checked in steps 470 and 480, respectively, has been met. Then, the procedure loops back to step 410.

All the method steps, as well as any sub-sequence of steps, described with reference to Figure 4 above can be controlled by means of a programmed computer apparatus. In addition, although the embodiments of the invention described above with reference to the figures include a computer and processes performed in a computer, the invention extends to computer programs, especially computer programs on or in a carrier adapted to practically implement the invention. The program may be in the form of source code, object code, a code which constitutes an intermediate between source and object code, such as in partially compiled form, or in any other form suitable for use in implementing the process according to the invention. The carrier can be any entity or device which is capable of carrying the program.

For example, the carrier may comprise a storage medium such as a flash memory, a ROM (Read Only Memory), for example a CD (Compact Disc) or a semiconductor ROM, an EPROM (Erasable Programmable Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read) Only Memory), or a magnetic recording medium, such as a floppy disk or hard disk. In addition, the carrier may be a transmitting carrier such as an electrical or optical signal, which may be conducted through an electrical or optical cable or via radio or otherwise. When the program is formed by a signal which can be conducted directly by a cable or other device or means, the carrier can be constituted by such a cable, device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, where the integrated circuit is adapted to perform, or to be used in performing, the actual processes.

The invention is not limited to the embodiments described with reference to the figures but can be varied freely within the scope of the appended claims.

Claims (15)

10 15 20 25 30 527 951 13 Patent claims An arrangement for determining a city traffic situation reviewed by a wheeled motor vehicle, comprising: a speedometer (310) adapted to record a vehicle speed (v); "a comparator (320) adapted to compare the vehicle speed (v) with a threshold speed (vC | Ty); and a traffic situation classification unit (330) adapted to, if, at a time to, the vehicle speed (v) be less than the threshold speed (VCW); ), determine a left wheel drive (sL) traveled by the left front wheel (210) of said vehicle during a measurement period (T) after the time to, determine a right wheel drive (sR) traveled by the right front wheel (211) of said vehicle during the measurement period. (T), determine a distance difference between the left wheel distance (sL) and the right wheel distance (sR), and if the absolute value of the distance difference exceeds a threshold distance (Scirv), define at least the measuring period (T) as an interval (lcny) during which said vehicle has undergone an urban traffic situation, and, after two, determine the distance difference between the left-wheel section (sL) and the right-wheel section (sR) on repeated measurement occasions, the interval (limb) during which said fo rdon undergoes the city traffic situation is interrupted if, over a control distance traveled (sHMEOUT) traveled by said vehicle after the time to, the absolute value of the distance difference has not exceeded the threshold distance (sem) at any of the said measurement occasions, where the control distance traveled (STIMEOUT) vehicles for a period ranging from the time to (t0 + ty) to a certain later time (t0 + tz). amended requirements 10 15 20 25 30 527 951 14 An arrangement according to claim 1, characterized in that the traffic situation classification unit (330) is adapted to interrupt the interval (limb) during which said vehicle undergoes the city traffic situation at a time (t0 + t ,,) after two then the vehicle speed ( v) for the first time equals, or exceeds, the threshold speed (VCW). An arrangement according to claim 2, characterized in that the traffic situation classification unit (330) is adapted to, after two, determine said distance difference in a sliding measuring window, which has an extension in time equal to the measuring period (T). An arrangement according to claim 3, characterized in that consecutive windows of the sliding measuring window at least partially overlap each other. An arrangement according to claim 2, characterized in that the traffic situation classification unit (330) is adapted to, after two, determine said distance difference at said repeated measurement occasions, where two consecutive measurement occasions are separated by at least one interval equivalent to the measurement period (T) . An arrangement according to any one of claims 1 to 5, characterized in that the arrangement comprises means (210a, 211a) adapted to record a wheel speed for the left and right front wheels (210; 211) during the measuring period (T); and the traffic situation classification unit (330) is adapted to determine the left and right wheel distances (sL, sR) based on said wheel speeds. A wheeled motor vehicle (300), characterized in that it comprises an arrangement according to any one of claims 1 to 6. A method for determining a city traffic situation through a wheeled motor vehicle, comprising the steps of: changing claims 10 15 20 25 30 527 951 15 recording a vehicle speed (v); comparing the vehicle speed (v) with a threshold speed (vom), and if at a time to, the vehicle speed (v) falls below the threshold speed (vom), determining a left wheel drive distance (sL) traveled by the left front wheel (210) of said vehicle during a measurement period (T) after time to, determining a right wheel distance (sR) traveled by the right front wheel (211) of said vehicle during the measurement period (T), determining a distance difference between the left wheel distance (sL) and the right wheel distance (sR) sR), and if the absolute value of the distance difference exceeds a threshold distance (sony), defining at least the measurement period (T) as an interval (iom) during which said vehicle has undergone a city traffic situation; whereby, after two, the distance difference between the left-wheel drive distance (sL) and the right-wheel drive distance (sR) is determined on repeated measuring occasions, and the interval (iom) during which said vehicle has undergone a city traffic situation is interrupted if, over a control distance (s fl MEoodT) to vehicles after the time to, the absolute value of the distance difference has not exceeded the threshold distance (as) at any of the mentioned measurement occasions. A method according to claim 8, characterized by interrupting the interval (iom) during which said vehicle undergoes the city traffic situation at a time after two when the vehicle speed (v) for the first time becomes equal to, or exceeds, the threshold speed (vooy) . A method according to claim 9, characterized by, after two, determining said distance difference in a sliding measuring window, which has an extension in time equal to the measuring period (T). A method according to claim 10, characterized in that consecutive modified claims 10 fw 527 951 16 measuring windows of the sliding measuring window at least partially overlap each other. A method according to claim 9, characterized by after two, determining said distance difference at said repeated measuring times, wherein two consecutive measuring times are separated by at least one interval equivalent to the measuring period (T). A method according to any one of claims 8 to 12, characterized by determining the left and right wheel distances (sL, sR) based on a respective wheel speed of the left and right front wheel (210; 211) recorded during the measurement period (T). A computer program directly downloadable to the internal memory of a computer, comprising software for controlling the steps according to any one of claims 8 to 13 when said program is run on the computer. A computer readable medium (335) having a stored program, the program being adapted to cause a computer to control the steps of any of claims 8 to 13.