SE535909C2 - Method and system for assessing a driver's braking behavior - Google Patents

Abstract

The invention relates to a method for assessing a driver's braking of a vehicle, comprising determining when a braking cycle begins; determining the time tengbrake when the vehicle's engine brake is used during the braking cycle; determining the time tshift for gear changes during the braking cycle; determining when the braking cycle ends; determining the total time ttotal for said braking cycle; processing ttotal and tengbrake with respect to tshift according to predetermined rules, and calculating a braking assessment value BA based on processed values for tengbrake and ttotal. The invention relates also to a system for assessing a driver's braking of a vehicle.

Description

In heavy vehicles, the driver can reduce the wear on brake pads, brake discs, etc. that are associated with the use of the wheel brakes. lfall e.g. only the service brake is used when a heavily loaded vehicle is driving on a long downhill slope, this can result in catastrophic consequences due to overheated brake pads, brake drums and / or brake pads. The use of auxiliary brakes should therefore be encouraged to make the driver's use of them more frequent.

Not all vehicles are equipped with all auxiliary brakes available.

For example, hydraulic retarder is not always used, depending on its cost.

However, the exhaust brake, which is also an auxiliary brake, is usually available on a heavy vehicle. However, the problem with evaluating the driver's use of the exhaust brake, and thus encouraging the driver to use it, is that the use of exhaust brakes in many countries is illegal, often at certain times of the day, as it sounds loud when used. It is also difficult to estimate the braking force that can be obtained from the exhaust brake in different driving cases.

WO 2007/139494 describes a device for determining a driver's ability to select a braking system. The driver's use of the braking system is compared with the driver's total use of the braking systems during braking to assess the driver's ability to use the braking system. The total use of the system is measured as energy consumed or use of the system. EP 1811481 describes a method and system for monitoring and analyzing a driver's driving style. Various parameters such as speed, vehicle speed, gear selection, etc. are monitored and used to create a driver profile that shows the driver's driving style.

The object of the invention is to achieve an improved method for evaluating the driver's ability to brake so that wear and fuel consumption is minimized, and in particular to encourage the driver to drive so that wear and fuel consumption is minimized. Summary of the Invention The above-described seam is achieved by a method for assessing a driver's braking behavior. The method includes: determining when a deceleration period begins; determine the time tengbmk, when the engine brake of the vehicle is used during the braking period; determine the time tsh ... it takes to put in a gear during the braking period; determine when the deceleration period ends; determine the total time t ..,.,. for said deceleration period; process tma. and tengbæke with respect to tsh ... according to predetermined rules, and calculate a brake assessment value BA based on processed values for tengbmke and tma., the rules include that: if tsm .. is greater than tshmmax, which is an adjustable maximum allowable time for shift, is processed tioiai according to tmahæ = tum. + thumb, where tsamme is a predetermined time period, tmamcc is the accumulated total time for said braking period, and whereby the calculated brake assessment care BA is presented to the driver.

According to another aspect, the purpose is achieved through a system for assessing a driver's braking behavior. The system comprises a control unit coupled to a first measuring unit adapted to determine when a deceleration period begins; a second measuring unit coupled to the control unit and adapted to determine the time tengmk, when the engine brake of the vehicle is used during the braking period and to emit a second time signal containing tengmm ... depending thereon; a third measuring unit coupled to the control unit and adapted to determine the time ts ... it takes to put in a gear during the braking period and to emit a third time signal containing tsk ... depending thereon; wherein the first measuring unit is adapted to determine when the deceleration period ends and to determine the total time t. °.,. for said deceleration period and outputting a first time signal containing inches .. to the control unit depending thereon, the control unit being further adapted to process t. °.,. and tengbfake with respect to tm ... according to predetermined rules, and to calculate a brake assessment value BA based on processed values for tengbfak, and twm., the rules comprising that: if tg ... is greater than tsmmax, which is an adjustable maximum allowed time for switching, processed t .., ._- ,. according to 10 15 20 25 30 535 909 4 fromma = tens + isempre, where thumb is a predetermined time period, tromaæ is the accumulated total time for said deceleration period, and wherein the calculated brake assessment value BA is presented to the driver.

The method and system achieve a way of assessing a driver's ability to brake in a way that minimizes wear and fuel consumption. This type of assessment of a driver's way of braking is very general and can be applied to many types of vehicles, such as trucks, buses, cars, without major requirements on how the vehicle is equipped.

According to one embodiment, the driver can receive direct feedback on his braking behavior, and can then rectify behaviors that have a negative impact on the environment and economy.

Through constant reminders of which driving style is desired, the driver can also maintain and improve his ability between training sessions.

The driver's braking behavior can also be scored, which is a positive way to encourage competition and commitment. You can thus make the driver have fun at work while improving the driving style.

Preferred embodiments are described in the dependent claims and in the detailed description.

Brief Description of the Attached Figures The invention will be described below with reference to the accompanying figures, of which: Figure 1 schematically illustrates an assessment system according to an embodiment of the invention.

Figure 2 shows a flow chart of the assessment method according to an embodiment of the invention.

Figure 3 shows a fate diagram of the assessment method according to another embodiment of the invention.

Figure 4 illustrates scoring of BA in Figure 2. Figure 5 shows a fate diagram of the assessment method according to a further embodiment of the invention.

Figure 6 shows an example of how the engine speed changes downhill.

Detailed Description of Exemplary Embodiments of Figure 1 schematically illustrates a system for assessing a driver's braking behavior in accordance with an embodiment of the invention. The system comprises a control unit which preferably comprises a processor unit for performing calculations etc. and at least one memory. The control unit is connected to a number of measuring units that are adapted to determine different variables. The first measuring unit is adapted to determine when a deceleration period begins and when it ends, and to determine the total time tioiai for the deceleration period and output a first time signal containing tioiai to the Control Unit accordingly. Depending on the situation to be assessed, the first unit of measurement is adapted to monitor and calculate various parameters and signals such as the vehicle's speed, acceleration, the vehicle's driving resistance, etc. to determine when a deceleration period begins and ends. Figure 1 schematically illustrates this as an arrow to the first unit of measurement. The second measuring unit connected to the control unit is adapted to determine the time teiigiiiaiie when the vehicle's engine brake is used during the braking period, and to emit a second time signal containing teiigbiiiii, depending thereon. The inputs to the second measuring unit are according to an embodiment similar to those of the first measuring unit. The third unit of measurement is adapted to determine the time tsiiiii for shifts during the deceleration period and to emit a third time signal containing tsmn accordingly. The third measuring unit then receives, for example, information from the gear system in the vehicle about when and which gears are used. The control unit is adapted to process tioiai and teiigime with respect to tsiiiii according to predetermined rules, and to calculate a brake assessment value BA based on the processed values for tengbiaiie and tioiai. The measuring units described are, according to one embodiment, functional units that can be included in the control unit. The control unit preferably comprises a processor unit which is adapted to perform calculations etc., and at least one memory.

According to one embodiment, the calculated brake assessment value BA is presented to the driver on a display. The value BA can, for example, be displayed as points in the form of a numerical value, or as symbols. The value BA can also be feedback audibly to the driver. According to one embodiment, the value BA can be stored in the memory in the control unit, or sent to a central unit external to the vehicle for further analysis.

According to one embodiment, the system comprises a fourth measuring unit adapted to determine the engine speed during the deceleration period. The measuring unit is then adapted to receive signals from the motor that indicate the engine speed. The fourth measuring unit is illustrated in Figure 1. In this embodiment, the control unit is adapted to process tm ... and tengbmke with respect to tsh ... and neng according to predetermined rules, and to calculate a brake assessment value BA based on processed values for tengbmke and kom. Thus, the driver's use of the correct gear for the situation can be assessed, and the driver can get feedback on his choice of gear.

The invention also relates to a method for assessing a driver's braking behavior. The method will now be explained with reference to the fate diagram in Figure 2. In a first step S21 is determined when a deceleration period begins. This can be different depending on which braking situation is to be assessed, which will be explained below. In a second step S22, the time tengbfa ... is determined when the vehicle's engine brake is used during the braking period. In a third step S23, the time ts ... is determined for shifts during the deceleration period. In a fourth step S24 it is determined when the deceleration period ends, which as in step S21 may be different for different situations. In a fifth step S25, the total time tens for the deceleration period is determined, and in a sixth step S26, tm ... and tengbmke with respect to ts ... are processed according to predetermined rules. In a seventh step S27, a brake assessment value BA is calculated based on the processed values for tengnrake AND tens of 535 909 According to one embodiment, BA is calculated according to BA = tengbmkeaæ / tmtaiaæ. In this way, a BA value between 0 and 1 is obtained, and the percentage time that the engine brake has been used can be calculated, which is shown in Figure 4.

A deceleration period can start in different ways depending on the situation the vehicle is in. The most described are a number of braking situations in which a driver can actively take measures to reduce wear and tear on the vehicle and also fuel consumption, and how these can be detected and assessed.

Situation In this situation, the driver actively brakes to slow down. A skilled driver consistently downshifts to contribute as much engine braking power as possible and also to avoid the engine having to idle during braking, which costs fuel. You should also not put the vehicle's gearbox in neutral during braking, except at very low speeds.

To detect and assess the driver's braking behavior in situation A, the system explained with reference to Figure 1 and the method explained with reference to Figure 2 are used. a predetermined threshold value. The braking period is considered completed when the driver accelerates or when the vehicle's speed falls below a given threshold. The time in which the engine brake is used is determined, and at e.g. coupling use is given a permitted time for switching. According to one embodiment, the rules then include that if the time it takes to change tshm is greater than tshi fi max, which is an adjustable maximum permitted time for change, the bill is processed. according to tmrahæ = tm, + tsampre, where inch ”is a predetermined time period. This is illustrated in figure 3. When the vehicle is braked with the engine brake, the tengbm and tm are increased by tfimpre. When the vehicle is shifted, tengbmk. Does not increase, and tens until a maximum time for shifting has elapsed, tshmmax.

If the maximum time has elapsed, but no gear has been engaged yet, only tm is increased. with 10 15 20 25 30 535 909 8 tsamme, resulting in tfomm. This is repeated until a gear is engaged, or the braking period is completed.

In order for the deceleration to be assessed at all, according to one embodiment a certain total braking time is required. This may depend on the speed of the vehicle.

The driver is preferably given a BA value in the form of a score based on the time gngbfak., When the engine brake has been used related to the total braking time tens, which is illustrated in Figure 4. The expected proportion of engine brake, ie the BA value, may depend on the vehicle speed. Figure 4 illustrates the limits of the BA value with F. ° w (v.,) And Fhigh (v.,), Ie the limits of the vehicle's engine braking force at a certain vehicle speed vo. When the driver's ability has been assessed, this is shown to the driver with, for example, symbols and / or points. If a particular behavior is detected, e.g. that the driver is disengaged and braked at high speeds, a tip can be shown to the driver on the display where he is encouraged not to use the clutch and instead use the engine brake.

The driver gets good grades when the speed is reduced as the driver makes consistent shifts.

No fuel injection is needed and there is less wear on the service brakes.

According to one embodiment, consideration is also given to whether the vehicle's exhaust brake is used, which has a positive effect on the driver's rating for the braking method.

Situation B In this situation, the driver wants to keep the speed of the vehicle on a downhill slope, thus ensuring that the vehicle does not increase speed. A skilled driver makes sure to downshift and maintain a higher engine speed that helps reduce wear on the brakes. In these situations, exhaust brake use is also preferable. Above all, they want to reduce the wear on the service brakes, but also reduce the risk of brake overheating, which can lead to an accident. 10 15 20 25 30 535 909 9 To detect and assess the driver's braking behavior in situation B, use the method explained with reference to Figure 2, with some additional method steps illustrated in Figure 5.

A deceleration period begins, for example, when the vehicle begins a downhill slope. Downhill slopes can be detected in many ways. One way is to calculate the vehicle's driving resistance based on expected acceleration at a certain engine power. All external forces on the vehicle can then be assembled in driving resistance and include i.a. gravity, rolling resistance and air resistance. The deceleration period is considered to end when the driver accelerates or when the vehicle's speed falls below a given threshold, or when the driving resistance falls below a certain value.

The driver's gear selection is analyzed during braking and two times are calculated, tmomfoms and tmaj. Figure 5 illustrates that faith. increased by tmpre when the engine brake is not used, ie when no gear is engaged. Preferably, a certain time is also given here, to shift, just as in situation A. When a braking period has begun and the vehicle brakes, the engine speed is determined according to an embodiment during the braking period. com. and tengbfake are then processed with respect to tshm and neng according to predetermined rules, and a brake assessment value BA is calculated based on the processed values for tengbmke and tmtar. In this way, the assessment takes into account the speed of the engine, and also how long the driver takes for shifting.

According to one embodiment, said predetermined rules include comparing neng with limit values nenghigh and nenglow for the engine speed, where nanm-gi, is an upper limit value and nenglow is a lower limit value. This results in a way of assessing the driver's choice of gear.

According to another embodiment, the rules include that if neng is greater than nenghjgh, ttotal is treated according to ttotalacc = tiotal + tsample AND tengbrake is not tengbrakeacc = tengbrake + tsample, where tmtaiaæ and tengbmkeacc are the accumulated values for each time period. Then the driver is judged to have applied the correct gear for the situation, and the required engine brake is used.

If the neeg is less than or equal to the nenghigh, check according to one embodiment if the driver uses the exhaust brake during the braking period. If this is the case. and nene is greater than neeeexheeen fl eke, tteiei is processed according to tlotaiaæ = tteiei + teemee, and tengbrake according to tengbrakeacc = tengbrake + tsample- where nengexhaustbrake is a speed limit value related to the exhaust brake. If the control unit receives a signal indicating that the vehicle's exhaust brake has been applied during the braking period and the neeg is greater than nengexeeuee fl eke, tm is processed. according to tmteeee = tme, + teemeie, and tengefeke according to tengemkeeee = tengemke + teemeie. In this way, the driver's use of the exhaust brake during the braking period can also be evaluated.

According to one embodiment, if neng is greater than nengew and less nenghigh, threats are processed according to tmleiaec = tsampie + tiotal and tengbfeke according to tenebfakeaæ = tengbfete + teemeie * (neng-neng | e ,,,) / (nenghigh-nengiew). The driver thus brakes the engine, but the gear selection is not the best for the situation. Shifting is thus suitable, and according to one embodiment, this is suggested for the driver in the display. A suitable gear can then be calculated and suggested. If the total engine braking force Fengemke at the recommended engine speed nenweq is greater than the total braking force Ffeir fl eke, no lower gear is required and no action is taken as the driver should not be advised to brake more than necessary. Braking more than necessary is of course unnecessary and ultimately costs fuel. The total braking force F.e, e, eke is thus including service brakes. The recommended engine speed nenwee is a threshold value that, for example, indicates the minimum engine speed required to actively reduce the vehicle's speed during engine braking. If the total engine braking force Feneefeke at the recommended engine speed neegee is less than or equal to the total braking force Fieiemke, and / or if nene is less than or equal to neeglew, 10 535 909 ll be machined according to an embodiment tmta. according to ttotam = tens + tsampie, where tsampie is, as previously mentioned, a predetermined period of time. Preferably, downshifting to the driver is now suggested. Here, too, a suitable gear can be calculated and suggested.

Figure 6 shows an example of how the vehicle's speed varies during a time period t when the driver wants to keep the speed on a downhill slope, ie situation B. The figure also shows when the vehicle's exhaust brake is on or off during the same time period. Table 1 shows how tens and tengbmke will be calculated i.a. depending on the driver's gear selection during time period t.

Table 1 Time period Description Measures t1 Engine brakes - speeds higher than nenghigh tiotaim = tm; + tsampte, tengbrakeacc = tengbrake 4 'tsample tg Engine brakes - speed less than tmmaæ = ttotat + tsamp., nenghigh men stÖffe än nenglow tengbrakeacc = tengbrake + tsampleïnenfnenglow) I (nenghigrnenglow) t3 Motor brakes nam - varv + nw +. tsampie t4 Gears (max. permitted time: tshmmax) None 15 Engine brakes - speed higher than nengmgh tma | am = tmm + tsampie, tengbrakeacc = tengbrake + tsample ta Engine brakes - speed less than tmaiaæ = tm. + tsampia nenghigh men Stöffe än nenglow tengbrakeacc = tengbrake + tsamplewnenfnenglow) I (nenghigWÛenglow) t7 Exhaust brakes - speeds greater than tmtam = tm, + tsamme, nengexhasutbrake tengbrakeacc = tengbrake T 5sample 10 12 less Av 25 twtaiaæ = hotel + tsampie with nengexhasutbrake tengbrakeacc = tengbrake + Engine brakes - speed less than tsamplgïneng-nengiow) / nenghigh but dustier than nenglow (nenghiglfnenglow) tg Engine brakes - speed less than nengiow tmia tampia time period t1-t9 in the different situations above.

After braking, the driver's ability to score is scored in the same way as in situation A, but possibly with other parameters, according to figure 4. Tips can also be given afterwards to the driver on how he can handle a similar situation next time.

Situation C In this situation, the driver wants to roll freely, which means that the driver does not use gas and brake. For example, this can happen on a gentle downhill slope. Here, a gear should also be engaged instead of depressing the clutch pedal or using a neutral gear. There are reasons for this. For example. then the engine runs at idle without engaged gear, which means that fuel is consumed. The risk is often great that the extra energy gained by rolling still has to be slowed down.

To detect and assess situation C, the method and system described with reference to Figures 1 and 2 are used. The deceleration period is considered to end when the driver accelerates, if the vehicle's speed is below a given threshold. or if the driving resistance is less than a certain value.

According to one embodiment, the system is adapted to receive information about and take into account an upcoming traffic situation. This information can be obtained, for example, via radio messages that contain information about the position of the traffic situation. 10 15 20 25 30 535 909 13 The driver can then be made aware of traffic situations when the vehicle's speed should be reduced, for example a traffic accident or queue, and adjust the vehicle's speed accordingly. Information about a future road situation can also be obtained via map data about the future road and the vehicle's position. The position of the vehicle can, for example, be obtained via a GPS device in the vehicle. The driver can then be made aware of traffic situations when the vehicle's speed should be reduced, for example a roundabout, a road junction, etc., and adapt the vehicle's speed to the traffic situation. A further example of a road situation is a speed limit which means that the driver must slow down the vehicle.

The driver is preferably encouraged to use the engine brake to reduce or adjust the speed for the oncoming traffic situation. As the driver only uses the engine brake during the braking period to reduce the speed, this is rewarded according to an embodiment with a maximum brake assessment value BA and an encouraging tip shown to the driver via the display. The driver is preferably given a score based on the time tengbmke when the engine brake has been used related to the total braking time twm., Which is illustrated in figure 4. The expected proportion of engine brake may depend on the speed of the vehicle. When the vehicle exceeds a certain speed without a gear being engaged, a tip is preferably given via the display which encourages the driver to put in a gear alt. release the clutch pedal.

Preferably, a certain time is also given here ghmma, to shift, just as in situation A and B. When gear is engaged, the driver is rewarded by adding as much time tsampie to tengb fi ke as to tens. which means that the calculated brake assessment value BA will be higher.

The invention also relates to a computer program product, comprising computer program instructions for causing a computer system in a vehicle to perform the steps according to the described method when the computer program instructions are run on said computer system. The invention also comprises a computer program product where the computer program instructions are stored on a medium readable by a computer system. The present invention is not limited to the embodiments described above. Various alternatives, modifications and equivalents can be used.

Therefore, the above-mentioned embodiments do not limit the scope of the invention, which is defined by the appended claims.

Claims (14)

10 15 20 25 30 535 909 15 Patent claims A method for assessing a driver's braking behavior, characterized in that the method comprises: - determining when a braking period begins; - determine the time tengbmk, when the vehicle's engine brake is used during the braking period; - determine the time tshm it takes to put in a gear during the braking period; - determine when the braking period ends; - determining the total time nom for said deceleration period; - processing tmlal and tengbmke with respect to tsm according to predetermined rules, and calculating a brake assessment value BA based on processed values for tengbmk, and even, the rules comprising: if tshm is greater than tshmmax, which is an adjustable maximum allowable time for change, tens are processed according to tmlalaæ = tmal + tsmwe, where bample is a predetermined time period, tlolam is the accumulated total time of said deceleration period, and the calculated brake assessment value BA is presented to the driver. Method according to claim 1, wherein BA is calculated according to BA = tengb fi keam I twmaæ, where tengbækeaæ is the accumulated time when the vehicle's engine brake is used during a braking period. A method according to any one of the preceding claims, wherein the method comprises - determining the engine speed during the braking period; - process flora. and tengbmke with respect to tshm and nen., according to predetermined rules, and calculate a brake assessment value BA based on processed values for tmgbmke and tens The method of claim 3, wherein said predetermined rules comprise comparing nens with limit values nenghigh and nengm, for the engine speed, where nenghigh is an upper limit value and nengmw is a lower limit value. 10 15 20 25 30 535 909 16 The method of claim 4, wherein the rules comprise that: if nen, is greater than nenghigh, tmla is processed. according to tmtahæ = tens + tsampæ and tengbmke a fi gf ïengbrakeaw = fengbrake + ïsample if nen, is greater than or equal to nengmw and less than or equal to nenghigh, tens are processed according to tiolalm = temple + tens and tengbak. according to tengbakeaæ = tengbake + ïsample * (neng-HangmvJ / (flenghigh- fl englow). 000 if nens, is less than nenglow, tens are processed according to ttolalaæ = tm; + tsample, where tsample is a predetermined time period. A method according to any one of claims 3-5, wherein the method comprises that if the vehicle's exhaust brake has been used during the braking period and hm is greater than nengexnaustbrane. beafbeta tiotal according to ttoialacc = trutar + ïsample. 000 ïengbrake 9n | i9t tengbrakeacc = tengbæke + tsample, where nengexhausmfak, is a speed limit value related to the exhaust brake. 7. A system for assessing a driver's braking behavior, characterized in that the system comprises a control unit coupled to a first measuring unit adapted to determine when a braking period begins; a second measuring unit coupled to the control unit and adapted to determine the time tengbfak, when the engine brake of the vehicle is used during the braking period and to emit a second time signal containing tengbmke depending thereon; a third measuring unit coupled to the control unit and adapted to determine the time it takes to put in a gear during the braking period and to emit a third time signal containing tshm depending thereon; wherein the first measuring unit is adapted to determine when the deceleration period ends and to determine the total time now. for said deceleration period and emit a first time signal containing note. to the control unit as a result thereof, wherein the control unit is further adapted to process tens and tmgbmke with respect to tshm according to predetermined rules, and to calculate a brake assessment value BA based on processed values for tengmake and tens. wherein the rules include that: if tsm fl is greater than tshi fl max, which is an adjustable maximum allowable time for switching, tens are processed according to tens = tom + tsample, where tsample is a predetermined time period, ttolalm is the accumulated the total time for said braking period, and wherein the calculated brake assessment value BA is presented to the driver on a display. A system according to claim 7, wherein BA is calculated according to BA = tgngbfgkgagç I tmtæacc, tengbygkeaçç engine brake is used during a braking period. A system according to any one of claims 7 to 8, wherein the system comprises a fourth measuring unit adapted to determine the engine speed during the braking period; and that the control unit is adapted to process tm: and ßngbfake with respect to tshi fi and nens according to predetermined rules, and to calculate a brake assessment value BA based on processed values for tmwak., and tion ... The system of claim 9, wherein said predetermined rules comprise comparing neng with limit values nenghigh and nengmw for the engine speed, where nenghigh is an upper limit value and nengtow is a lower limit value. A system according to claim 10, wherein the rules comprise that: If neng is stöffe than Ûenghigh, ttotal is not used ttotalacc = ttotal + tsample and tengbrake a fi gt tengbrakeaoc = tengbrake + tsample if neng is greater than or equal to nengiow and less or equal to nenghigh ttotal e flfi gt ttotalacc = tsample 4 'ttotal ÛCh l-engbrake eÜHQt tengbrakeacc = tengbrake + tsample i (neng-nenglowymenghiglFnenglow) i And if new is less than nengiow, tioiai is processed according to tmiaamp., = is for tmiaamp. period. A system according to any one of claims 9 to 11, wherein if the control unit receives a signal indicating that the vehicle's exhaust brake has been applied during the braking period and nmg is greater than nengemustbmke, process inches, according to within = flora 't ïsampie, where nengexhausmæke is a speed limit value related to the exhaust brake 535 909 18 A computer program product, comprising computer program instructions for causing a computer system in a vehicle to perform the steps of the method of any of claims 1 to 6, when the computer program instructions are run on said computer system. The computer program product of claim 13, wherein the computer program instructions are stored on a computer system readable medium.