SE1050335A1 - Method and module in connection with cruise control - Google Patents

Description

2 higher speed than normal. By avoiding unnecessary acceleration and utilizing the vehicle's kinetic energy, fuel can be saved.

The most described are examples of cruise control that try to reduce the amount of fuel used when the road changes character. The cruise control described in U.S. Pat. No. 6,206,121 B1 strives for the vehicle to maintain the desired reference speed. A control unit controls how much fuel is to be injected into the engine depending on the speed of the vehicle. If the speed of the vehicle is higher than a desired target speed, the control unit in the vehicle determines that the vehicle is on a downhill slope, and the fuel injection is throttled.

US 2008/0306669 A1 describes a cruise control which interacts with throttling of fuel injection in the engine when it is on a steep downhill. The cruise control constantly strives to maintain the reference speed, which means that the signal to the accelerator pedal to increase the speed and the signal for throttled fuel injection can be sent several times under the same downhill, which can result in a jerky drive. In order to have smooth transitions between the various states, the signal for the fuel injection can be ramped up. The slope of the road is determined by continuously evaluating the speed of the vehicle.

The object of the present invention is to provide an improved method for reducing fuel consumption and / or reducing the driving time when a vehicle is driven by means of cruise control.

Summary of the invention The object described above is achieved by a method for calculating speed setpoints vref to a control system in a vehicle, which comprises A) determining a horizon by means of position data and map data of a future road containing road segments and at least one property for each road segments; B) calculate speed setpoints vref for the vehicle's control system over the horizon depending on rules linked to the characteristics of the road segments, and then a reduction of the vehicle's input speed wine, in to a road segment is calculated to be necessary for the final speed VSM; in the road segment shall be 5 vmax and thus avoid unnecessary braking, the method includes: C) calculating a starting position on the horizon when the fuel injection to the vehicle is to be throttled, in order to achieve a reduction to 10 15 20 25 30 3 viii, provided that vmin S vfef S viiiax, where viiiiii and viiiax set the permissible speed limits for vief, this starting position being taken into account in further calculations of speed setpoints vi-ef; and D) control the vehicle according to the speed setpoints viiif.

According to another aspect, the object is achieved by a module for determining speed setpoints vief to a vehicle control system, the module comprising a horizon unit adapted to determine a horizon by means of position data and map data of a future road containing road segments and at least one property for each road segment ; the module also comprises a processor unit adapted to: calculate speed setpoints vief for the vehicle's control system over the horizon depending on rules linked to the characteristics of the road segments, and when a reduction of the vehicle's input speed viiii to a road segment is considered necessary for the final speed vsiiiii in the road segment to be then avoid unnecessary braking, the processor unit is adapted to: calculate a starting position on the horizon when the fuel injection to the vehicle is to be throttled, in order to achieve a reduction to viii, i provided that it wins. S vief S viiiaii, where viiiiii and viiiax set the permissible speed limits for vief, this starting position being taken into account in further calculations of speed setpoints vief; after which the vehicle is regulated according to the speed setpoints viiif.

The vehicle's speed is predicted along a horizon that is typically 1-2 km long. When the speed is predicted to either exceed or fall below predetermined thresholds viiiiii and viiiax around the set speed set by the driver, the algorithm tries to adjust the reference speed vief, i.e. the equipped speed of the vehicle's cruise control, in previous segments (closer to the vehicle) on the horizon within specified ranges viiiiii and viiiax.

In order to restrict the fuel supply to the vehicle's engine, the vehicle's reference speed can be rapidly reduced in one step. Throttling the fuel supply means that no fuel is injected into the engine. The reduction must be large enough to achieve towing torque. By restricting the fuel supply to the engine to avoid unnecessary burning due to too high a speed in, for example, a downhill slope or curve, it is possible to reduce the driving time compared to ramping down the vehicle's speed. A ramping of the vehicle speed can be performed with Torricelli's formula (1), which means that the reference speed of the vehicle increases or decreases substantially linearly. By restricting the fuel supply, the same speed reduction can take place in a shorter time, which means less lost driving time. The reduced driving time can instead be converted into a fuel saving by lowering the vehicle's speed on a level road. The driver usually notices the reduction, which makes the speed reduction safer because the driver is aware of what will happen.

A reduction in the vehicle's speed by restricting the fuel supply requires that the vehicle has a significant mass to meet comfort requirements. The driver of the vehicle may otherwise experience the behavior of the vehicle as unexpected and not comfortable, and fellow road users may find it difficult to anticipate such a driving style. Preferred embodiments are described in the dependent claims and in the detailed description.

Brief description of the accompanying figures The invention will be described below with reference to the accompanying figures, of which: Figure 1 shows a module according to the invention adapted to determine speed setpoints vref.

Figure 2 illustrates the length of a steering system's horizon in relation to the length of the future road of the vehicle.

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

Figure 4 illustrates a comparison of the vehicle speed when different cruise control methods are used.

Figure 5 illustrates how the fuel injection varies between the different methods in Figure 4.

Figure 6 shows an example of how the starting position for throttling of fuel supply is calculated according to an embodiment of the invention.

Detailed Description of Preferred Embodiments of the Invention By using information about a vehicle's future path, the vehicle's reference velocity to the engine control system in the vehicle can be determined in advance to save fuel, increase safety and increase comfort. Other setpoints for other control systems can also be regulated. The topography greatly affects the control of the powertrain in particular for heavy vehicles, as it requires a much greater torque to drive up a hill than to drive downhill, and because it is not possible to drive up some slopes without having to downshift.

The vehicle is equipped with positioning systems and map information, and through position data from the positioning system and topology data from the map information, a horizon is built up that describes what the future road looks like. In describing the present invention, GPS (Global Positioning System) is used to determine position data for the vehicle, but other types of global or regional positioning systems are also conceivable for providing position data to the vehicle, which for example use radio receivers to determine the position of the vehicle. The vehicle can also use sensors to scan the surroundings and thus determine its position.

Figure 1 shows how information about the future road is taken in via a map and GPS in a unit.

The future road is in the following exemplified as a single route for the vehicle, but it is understood that various possible future roads are included as information via map and GPS or other positioning system. The driver can also register the start destination and end destination for the planned journey, and the unit then calculates with the help of map data etc. a suitable route to drive. The route, or if there are fl your future alternative routes: the routes, are sent in pieces via CAN (Controller Area Network) to a module for calculating setpoints. The module can be separated from or part of the systems that are to use the setpoints for regulation. Alternatively, the unit with map and positioning system can also be part of a system that will use the setpoints for regulation. In the module, the pieces are then assembled in a horizon unit into a horizon and processed by the processor unit to create an internal horizon that the control system can regulate according to. If there are fl your alternative routes, your internal horizons are created for different route alternatives.

The steering system can be any of the various steering systems in the vehicle, such as the engine steering system, gearbox steering system or any other steering system. Usually a horizon is put together for each control system, because the control systems regulate according to different parameters.

The horizon is then constantly built on with new pieces from the unit with GPS and 10 15 20 25 30 map data, to get the desired length of the horizon. The internal horizon is thus continuously updated during the vehicle's journey, as illustrated in Figure 2.

CAN denotes a serial bus system, specially developed for use in vehicles. The CAN data bus provides the opportunity for digital data exchange between sensors, control components, actuators, controllers, etc. and ensures that styr your controllers can access the signals from a specific sensor, to use these to control their connected components.

The description uses a number of designations that have the following meaning: vsiii: preselected seat speed for, for example, the driver vief: the reference speed exhibited is within vmin S vfef S viiiax to keep the vehicle speed within the range viiiiii to viiiax if possible. viii, i: the input speed into segment (i). vsiiii, i: the final speed in segment (i) with the input speed viii, i, with standard cruise control vpieii, i_i: predicted final speed in segment (il) with another small or negative engine number, for example towing torque Aviii, mi: desired reduction of speed before road segments ( i) Avpieiiii: possible decrease during road segment (il), predicted with, for example, towing torque Aviii, iesi: the remaining decrease that needs to be made, Aviii, ioi - Avpieii, i_i, - Avpieii, i_2 ..., which decreases continuously after the preceding segment considered.

The remaining terms are described continuously in the text.

The present invention relates to a method as shown in the fate diagram in Figure 3 according to an embodiment of the invention. The following are examples for just one horizon, but it is understood that fl your horizons for different alternative future paths can be built in parallel. In a first step A), the method comprises determining a horizon by means of position data and map data of a future road which contains road segments and at least one property for each road segment. A characteristic can be, for example, the length, slope, curve radius, road signs, various obstacles, etc. As the vehicle is driven, the horizon module builds the pieces together into a horizon of the future road, where the length of the horizon is typically in the order of 1-2 km. The horizon unit keeps track of where on the road the vehicle is and constantly builds the horizon so that the length of the horizon is kept constant, as illustrated in figure 2. When the end goal of the journey is within the length of the horizon, according to one embodiment the horizon is no longer built is not interesting.

The horizon includes road segments that have egenskaper your characteristics linked to them. The horizon is exemplified here in the matrix form, where each column describes a property of a road segment. A matrix describing 80 m ahead of a future road can look like this: dx,% 20, 0.2 20, 0.1, 20, - 0.1 20, - 0.3 where the first column is the length of each road segment in meters (dx) and the the second column is the slope of each road segment in%. The matrix should be interpreted as meaning that from the current position of the vehicle and 20 meters ahead the slope is 0.2%, followed by 20 meters with a slope of 0.l% etc. The values for road segments and slope do not have to be stated as relative values, but can instead be stated as absolute values. The matrix is advantageously vector-shaped, but can instead be of pointer structure, in the form of data packets or the like.

Then, in step B), speed setpoints vref are calculated for the vehicle control system over the horizon depending on rules linked to the characteristics of the road segments. Preferably, each road segment is classified in a road class depending on its property or characteristics, and the road class of each road segment then determines which rules apply to the road segment when calculating speed setpoints. How this is done is explained in more detail below.

According to one embodiment, the method comprises calculating threshold values for at least one property of the road segments depending on one or fl your vehicle-specific values, where the threshold values set limits for dividing the road segments into different road classes. In the example where the properties of the road segments are slope, threshold values for the slope of the road segments are calculated. The threshold values for the property in question are calculated according to an embodiment of the invention by one or fl your vehicle-specific values, such as current gear ratio, current vehicle weight, engine maximum torque curve, mechanical friction and / or the vehicle's estimated driving resistance at current speed. An in-vehicle control system that estimates driving resistance at the current speed is used. Gears and maximum torques are known variables in the vehicle's control system and vehicle weight is estimated online.

At the top are presented examples of five different road classes into which the road segments can be classified, when the slope of the road segments is used to make decisions about the steering of the vehicle: Flat road: Road segments that have a slope between 0i a tolerance.

Steep uphill: Road segments that have a slope so steep that the vehicle cannot keep up with the speed of the current gear.

Slight uphill: Road segments that have a slope between tolerance and threshold value for steep uphills.

Steep downhill: Road segments that have a slope downhill so steep that the vehicle accelerates by the slope itself.

Slight down fi ir: Road segment that has a slope downhill between the negative tolerance and the threshold for steep downhill.

According to an embodiment of the invention, the characteristics of the road segment are their length and slope, and to classify the road segments into the road classes described above, threshold values are calculated in the form of two slope threshold values, lmin and lmax, where lmin is the slope that the road segment must have the least to that the vehicle should accelerate by the slope itself on a downhill slope, and lmax is the slope value that the road segment can have the maximum for the vehicle to be able to maintain speed without shifting on an uphill slope. Thus, the vehicle 10 can be regulated according to the upcoming slope and length of the road, so that the vehicle can be driven in a fuel-efficient manner by means of cruise control in hilly terrain. In another embodiment, the characteristics of the road segments are their length and lateral acceleration, and threshold values are calculated in the form of lateral acceleration threshold values that classify the road segments according to how much lateral acceleration they provide. The speed of the vehicle can then be regulated so that the vehicle can be driven in a fuel-efficient and traffic-safe manner with regard to the curvature of the road, i.e. a possible speed reduction in front of a curve takes place as far as possible without the intervention of service brakes. As an example, the tolerance for the category "Flat road" is preferably between -0.05% to 0.05% when the vehicle is driven at 80 km / h.

Based on the same speed (80 km / h), lmin is usually calculated to be in the order of -2 to -7%, and lmax is usually 1 to 6%. However, these values depend a lot on the current gear ratio (gear + fixed rear axle gear ratio), as well as engine performance and total weight.

The property or characteristics of each road segment are then compared with the calculated threshold values, and each road segment on the horizon is classified into a road class depending on the comparisons.

Similar classes can instead or also exist for, for example, the curve radius of the road, where the curves could then be classified according to how much lateral acceleration they give.

If each road segment on the horizon has been classified in a road class, an internal horizon for the control system can then be calculated, depending on rules linked to the road classes in which the road segments on the horizon have been classified. The internal horizon comprises speed setpoints vref including input speeds vimi to each road segment, which the control system shall control according to. All road segments in the horizon are stepped through continuously, and as new road segments are added to the horizon, the entry speeds vimi are adjusted as needed in the road segments, within the range of the vehicle's seat speed vset. vset is the seat speed set by the driver and which is desired to be maintained by the vehicle's control system during the journey within a range. The interval is delimited by two speeds, vm, and vmax, which can be set manually by the driver, or set automatically by calculations of suitable intervals, which are preferably calculated in the module. According to one embodiment, a speed increase is ramped to obtain an input speed vimi and to give setpoints vref to the control system which causes a gradual increase in the speed of the vehicle. By ramping up a speed increase, gradual speed changes are calculated that need to be made to achieve the speed change. In other words, by ramping, a linear increase in speed is achieved.

The different rules for the road classes thus regulate how we are to adjust the entrance speed to each road segment. If a road segment (i) has been classified in the road class "Flat road", no change in the input speed vmi to the road segment will be made. When the reference speed is to be increased, Torricelli's equation (l) is used as below to calculate the constant acceleration a the vehicle must accelerate with in order to be able to drive the vehicle so that comfort requirements are met: Vszlulj: vzšaj -l-Zlals? where vimi is the entrance speed to the road segment (i), vsluni is the speed of the vehicle at the end of the road segment (i), a is the constant acceleration and s is the length of the road segment. For cases where the vehicle is predicted to reduce speed, the explanation follows below.

If a road segment has been classified in the road class “Steep up fi ir” or “Steep down”, the final velocity vshmi for the road segment (i) is predicted by solving equation (2) below: = - -f fl / a, where <2> a = -Cd-pA / 2 <2) b 2 Fvtrack _ Froll _ FOL Pltrack I (Teng i í fi nal i ígear fl Hgear)! Rwheel + Cb '(Vimi _ Visa) + CaF' (Vi: _ väv (6) 30 Fm ”= fl atCorr - M -g / l000- (C rrisoF 10 15 20 25 30 ll Fu = M - g - sin (arctan (0L)) (7) fl azcw = 1 / (1+ mig, / 2_7o) (s) where Cii is the air resistance coefficient , p is the density of the air, A is the largest cross-sectional area of the vehicle, Fiiack is the force acting from the engine nominal in the vehicle's direction of travel, Fioii is the force from the rolling resistance acting on the wheels, Fii is the force acting on the vehicle through the road segment inclination oc, Teiig is the engine nominal, ifiiiai is the final gear of the vehicle, igeai is the current gear ratio in the gearbox, ugeai is the efficiency of the gear system, rwiieei is the wheel radius of the vehicle, M is the mass of the vehicle, Cap and Ci, are speed dependent nd coefficients related to the rolling resistance of the wheels, Ciiisoi: is a constant term related to the rolling resistance of the wheels and viso is an ISO speed, for example 80 krn / h.

In road segments with the road class "Steep uphill" the final speed vsiiiii is then compared with viiiiii, and if vsiiiiii <viiiiii then viii, i shall be increased by Aviiiioi which is given by: AvínJat I _ Ving '1 vmin _ Vslutj) 9 or Avi ärii, negative, no change is made to viii, i.

In road segments with the road class "Steep downhill", the final speed vsiiii, i is compared with viiiaii, and if vsiiii, i> viiiax, viii, i shall be reduced by Aviii, ioi which is given by: (10) Avimtot I nun (Vinj _ Vmin 9 Vslutj _ Vmax) 9 if Aviii, ioi is zero or negative no change of viii, i.

When a reduction of the vehicle's entry speed viii, i to a road segment is calculated to be necessary for the final speed vsiiiii in the road segment to be in viiiax, thus avoiding unnecessary braking, the method comprises step C) to calculate a starting position on the horizon when the fuel source throttled, to achieve a decrease to viii, i. This starting position is included in further calculations of 10 15 20 25 30 12 speed setpoints vief. A condition for the lowering of viii, i is as mentioned that viiiiii 5 vfef S Vmax. Then in a step D) the vehicle is regulated according to the speed setpoints vief By lowering the vehicle's speed by throttling the fuel injection and using the vehicle's kinetic energy to roll down to the desired viii, i, the vehicle's speed can be reduced downhill and the energy the vehicle can be taken downhill without the vehicle having to be braked because it exceeds any speed limit. The vehicle also has a shorter driving time, which can be converted to lower fuel consumption by lowering the vehicle's average speed for the rest of the mileage.

A deceleration of the vehicle due to interrupted fuel supply requires that the vehicle has a significant mass to meet comfort requirements. If the vehicle does not have it, the deceleration takes place by using Torricelli's equation (l) instead. According to one embodiment, the method comprises determining the mass of the vehicle, and if the mass of the vehicle exceeds a predetermined threshold value, then step C) is performed, otherwise the reduction of the vehicle speed is calculated to achieve a reduction to viii, i using Torricelli's equation (1) .

The mass of the vehicle can be determined, for example, by the driver stating what the load or vehicle weighs or the mass of the vehicle being sensed by sensors. Interrupted fuel supply is preferably intended to be used on vehicles having a train weight of more than about 30 tonnes. Interrupted fuel supply can be used on vehicles that have a train weight greater than a predetermined weight in the range of 10 - 30 tonnes. The driver may otherwise experience the vehicle's behavior as unexpected and not comfortable. Even fellow road users would find it difficult to predict such a driving style.

To know how much the input speed viiii should be reduced, the maximum speed of the vehicle vsiiii, i after viiii, is predicted by formula (2). A desired decrease of viii, i is then calculated by calculating the velocity difference Aviii, mi, according to formula (10).

The speed vief of the vehicle must thus be reduced in the road segment or road segments before said road segment with the input speed viii, i begins. The method examines whether it is possible to decelerate under the road segment before, and if not, the road segment is examined before it and so on. To effect speed reduction, speed reduction of viiif of formula (2) is simulated in the road segment in which deceleration is possible, where Teiig is set to, for example, towing torque which is about -150 Nm, up to viii, i.

Calculation of starting position To see if it is possible to achieve a reduction of wine, i with Aviii, mi, which is the total desired reduction in the previous segment (closer to the vehicle), the simulated possible speed reduction is calculated Avpied, i_i = vsiiii, i_i - vpieii, i_i. vsiiii, i_i is thus the same velocity as viii, i.

Avpieii, i_i is thus the lowering of viii, i which is possible during the current road segment (i-1) when the motor torque is a small or negative moment, for example towing moment, and Aviii, ioi is the lowering of viii, i which is desired. If Aviii, ioi í Avpieii, i_i, the starting position for throttling of the fuel injection is calculated from the beginning of the road segment to:. . (OFF Staríposztzon = predJ-l _ AVinJul) Of the length of the (n) road segment predj-l If the whole desired lowering is not possible under the road segment (il), then a new desired lowering Aviii, iesi is calculated to be Aviii, ioi - Avpieii, i_i. The future road segments are being investigated as to whether further lowering can be implemented. Interruption conditions for lowering the speed in the preceding segment are that viii, i (where j 5 i-1) has reached viiiiii or that the entire horizon has been stepped back to the vehicle. Then the adjustments continue on segments in + 1.

In order to effect the throttling of the fuel supply, according to an embodiment vief is set to viiiiii - K, where K is a constant which is, for example, 5km / h. This should be a sufficient reduction of the speed to give trailing torque because the reduction of the reference speed takes place in one step , which is equivalent to restricting the fuel supply. Other ways of achieving throttling of fuel supply are also conceivable, e.g. 50% can be requested in the indicated engine nominal or otherwise control that the fuel injection is temporarily stopped.

An example of the method is shown at the top. Throttling of the fuel supply has been predicted to occur a certain number of segments before a downhill. vsei = 80 km / h, viiiiii = 73 krn / h and viiiax 10 15 20 25 30 14 = 85 km / h. A low speed vmin -5km / h = 68km / h is employed at this time as follows: vpfedikfefad = [80, 80, ..., 80, 79, 78, 77, 76, 75, 74, 73, 72, 71 , 70, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 85, 84, 83, 82, 81, 80, 80, 80 ] vfef: [80, 80,, 80, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68, 68 , 68, 68, 68, 68, 68, 68, 68, 68, 80, 80,80, 80, 80, 80] vpredicted is the predicted velocity along the horizon. Each element in the vectors corresponds to a segment with individual slope, for example the segments can be fixed or variable L m. Here the method has thus stepped back to where the prediction of vref = 80 km / h gives a maximum speed below the horizon that exceeds vmax, and sets here rpm = 68 km / h to get towing torque from the engine, and thus no fuel injection. The fuel is throttled throughout the downhill slope, until the vehicle no longer gets any speed off the hill and must be given gas so as not to sink during the vmin, alternatively to keep the vset.

Figures 4 and 5 illustrate what happens to the vehicle's speed and the amount of fuel added during throttle fuel injection before and under a hill, compared with traditional belief with constant speed brake and lowering with constant deceleration m.h.a. Torricelli's equation (1). Constant speed braking means that the vehicle avoids using the service brakes and instead uses the vehicle's auxiliary brakes (such as retarder and exhaust brake, and may also include electromagnetic brake (Thelma) and / or VEB (Volvo Engine Brake)) to slow down the vehicle's kinetic energy and maintain constant speed. . In figure 4, X1 shows the speed of a vehicle that uses cruise control with traditional cruise control set to vsct and constant speed brake set to keep the vehicle's maximum speed on steep descents to vkfb. Yl shows the speed of a vehicle where the speed is reduced by Torricelli's equation (1), and Zl shows the speed at which the reduction takes place by restricting the fuel supply. After the steep downhill, vfef = vset. Figure 5 shows how much fuel is injected into the vehicle's engine during the corresponding period. Zl is from the bend to vmf = vset, to then be set to vmf = vmin - K at the starting position for throttling the fuel supply, where K = 5 km / h. In Figure 5 it can be seen that the amount of fuel Z2 injected in one step decreases from the current fuel injection D 10 to 0%. Current fuel injection D is a value between 0 and 100%. The speed Z1 of the vehicle then goes down to vmin and then accelerates up to vmax of the mass of the vehicle and is then reduced to vset, while the amount of fuel Z2 injected into the engine is still zero. Here it can be noted that the driving modes for the speeds Y1 and Z1 consume approximately the same amount of fuel when the vset is equal, but that Z1 is higher for a longer period of time.

However, the driving modes that give the speeds Y1 and Z1 consume less fuel than the driving mode that gives the speed X1.

If it is desirable to reduce fuel consumption instead of reducing driving time, or making a combination of these, the driving time tT for the vehicle over the road segment is predicted.

This driving time is then compared with the driving time tTOR over the road segment when the vehicle's speed is instead reduced by using Torricelli's equation. A reduction of vref can then be calculated for the driving time tT to be tTOR, ie as long as when Torricelli's equation (1) is used. According to one embodiment, the method comprises lowering the speed so that a desired balance between fuel reduction and reduced driving time is achieved. A desired balance can, for example, be half of the calculated time gain, and the rest in a reduced amount of fuel. The driver can also be given the opportunity to choose what he prefers, shorter driving time, less fuel consumption or a combination, for example through a control. The driving time for the mileage is calculated according to: core = ds (12) where v is the speed of the vehicle and so and sT are the beginning and end of the road distance, respectively.

According to one embodiment, fuel consumption is calculated by integrating the predicted fuel fl fate over the road segment where the speed reduction is to take place according to: fuel = ífuel fl fate ds (13) Fuel fl fate is zero during throttling of the fuel supply. During the sections where the engine is running, the fuel är fate is a function of the engine torque and speed: 10 15 20 25 30 16 fuel fl fate = f (M, 0)) (14) This function describes the engine efficiency. The torque in formula (14) is the torque required to achieve the desired speed, i.e. the torque required to overcome driving resistance and provide any acceleration / deceleration.

According to one embodiment, the method comprises calculating speed setpoints viiif so that the vehicle is calculated to reach the desired set speed vsei after passing the road segment to which the input speed viii, i has been reduced. The lowering of the viiiii may then not be as great as when the vief is allowed to go down to the viiiiii after the hill, but the vehicle can instead maintain a higher speed and thus have a shorter driving time.

Figure 6 shows a number of different road segments (i-3) up to and including (i + 1). The speed that would have been obtained with a traditional cruise control is shown by a solid line vw in the lower figure.

An example is best described when the vehicle's speed is predicted to exceed viiiax in road segment (i) (same process as shown in figure 4). vsiiii, i which is the predicted final speed in the road segment (i) is calculated to exceed viiiax by 5 km / h according to formula (2). The desired reduction of the input speed viii, i to the road segment is then Aviii, ioi = 5 krn / h, an acceptable reduction also based on the fact that viiii then does not risk falling below viiiiii. The method first examines whether it is possible to decelerate during road segments (il) and the final speed of the vehicle vpieii, i_i is calculated by formula (2), when the engine torque is a small or negative torque, for example towing torque, and the possible reduction of speed under road segments (il) calculated, i.e. Avpieii, i_i. The velocity that would have been obtained in this case is shown as a dotted line. In the example, it is not possible to retard Aviii, ioi fi lllt out below road segments (i-1) because the road segment is a slightly sloping downhill, but the method must go back to road segments (i-2) which is a flat road, in order to retard further. Now the final speed of the vehicle vpieii, i_2 is predicted by formula (2), when the engine torque is a small or negative torque, for example towing torque, and the possible reduction of the speed during road segments (i-2) is calculated, i.e. Avpieii, i_2.

The speed that would have been obtained in this case is shown as a dashed line. Avpieii, i_2 is calculated by subtracting vpieii, i_2 from the calculated final speed vsiiii, i_2 in road segments (i-Z). If the remaining desired decrease (Avin, tOt-Avpred, i_1) is less than or equal to Avpred, pg, then the starting position for throttling of fuel supply under road segment (i-2) is calculated using formula (1 1). From the starting position, the fuel supply will then be restricted, while the vehicle is first decelerated to then be accelerated by its own weight and then decelerated back to the seat speed, vset.

If instead the entire desired reduction of 5 km / h is not possible during road segments (i-1) and (i-2), it is calculated how much the speed must be reduced during previous road segments (i-3) - (i-x). In that case, the procedure above is repeated, until the entire reduction of Avin, t0t = 5 krn / h is estimated to be completed, provided that it is feasible, otherwise the speed is reduced as much as possible and a higher vehicle speed than vmax is allowed if it is not possible to reduce speed more in the road segment ahead.

According to one embodiment, the method comprises that the driving resistance is adapted with a scale factor by comparing the estimated driving resistance with measured actual driving resistance in order to compensate for, for example, headwind or tailwind. The driving resistance that is estimated (rolling resistance, air resistance and normal force (hill), and other losses in, for example, the driveline) is thus multiplied by a scale factor so that the vehicle can adjust estimated driving resistance to take care of, for example, headwind / tailwind. The adaptation is done so that the estimated driving resistance, which is calculated on the basis of map data and parameters, is compared with how well the driving resistance works with measured driving resistance in real time. The adaptation takes place step by step so as not to have an uer octuating scale factor. By adapting, you can reach the predicted vmin with greater certainty, which could otherwise cost more than ramping down the reference speed.

The invention also relates to a module for determining speed setpoints vmf of a vehicle control system. The module comprises a horizon unit adapted to determine a horizon by means of position data and map data of a future road which contains road segments and at least one property for each road segment. The module also comprises a processor unit adapted to: calculate speed setpoints vref for the vehicle's control system over the horizon depending on rules linked to the characteristics of the road segments, and when a reduction of the vehicle's entry speed vimi to a road segment is considered necessary for the final speed vsluni in the road segment. thereby avoiding unnecessary braking, the processor unit is adapted to: calculate a starting position on the horizon when the fuel injection to the vehicle is to be throttled, in order to achieve a reduction to viii, provided that viiiin S vfef S Viiiax, where viiiiii and viiiax sets the permissible speed limits for vief, this starting position being taken into account in further calculations of speed setpoints vief; wherein the vehicle is regulated according to the speed setpoints vief. Through this module it is possible to calculate where throttling of the fuel injection is to take place in a predicted horizon of the vehicle's speed, so that the vehicle's speed is regulated in a fuel - optimal way.

The processor unit comprises the necessary hardware and program code for performing operations mentioned herein such as calculations and handling of data, and may for example comprise one or more CPUs with associated memory.

The processor unit is preferably adapted to predict the maximum speed of the vehicle vsiiii, i after the input speed viii, during a road segment, and calculate a desired reduction of viiii by calculating the speed difference Aviii, mi, by formula (10). In this way, the processor unit knows how much it is desirable to reduce the speed viii, i to a road segment.

According to one embodiment, the processor unit is adapted to simulate speed reduction of vief, where the engine torque Teiig is set to a small or negative torque, for example towing torque, up to viii, i, by using formula By simulating the vehicle speed at towing torque, one can obtain how much the speed drops and if it is possible to reduce the speed Aviii, ioi until viiii. The simulated viiii is calculated and named vpied, i_i.

According to one embodiment, the processor unit is adapted to calculate the simulated possible deceleration Avpied, i_i = vsiiii, i- vpied, i_i, and if the desired deceleration Aviii, mi 5 Avpieii, i_i, the starting position for throttling the fuel injection (11) is calculated. vsiiii, i_i is thus the same speed as viii, i. Avpied, i_i is thus the lowering of viiii that is possible during the current road segment (il) when the motor torque is set to a negative or small torque, for example towing torque, and Aviii, ioi is the lowering of viiii which is desired. Thus, a position has been calculated where the fuel injection can be throttled.

The module is preferably adapted to throttle the fuel injection by setting vttf to vmttt - K, where K is a constant which is for example Skm / h.

Preferably, the processor unit is adapted to calculate if Avttt, tot> Avpttd, t_1, which means that the entire desired reduction is not possible under the road segment (il), and further adapted to calculate a new desired reduction Avttt, test to be Avttt, tot - Avpttd, t_1, and investigate whether further lowering can be carried out in the preceding road segment (i-2) - (ix). In this way, the entire desired reduction of vtttt can be carried out, provided it is possible.

The module described so far provides the opportunity for reduced driving time for the vehicle. The reduced driving time can instead be converted in whole or in part to reduced fuel consumption for the vehicle. In order to achieve reduced fuel consumption, the processor unit according to this embodiment is adapted to predict the driving time tT of the vehicle over the road segment.

This driving time is then compared with the driving time tTOR over the road segment when the vehicle's speed is instead reduced by using Torricelli's equation (1), after which a reduction of the simulated speed is calculated for the driving time to be tTOR, to achieve a fuel reduction instead of reduced driving time. The module is preferably adapted to reduce the speed vttf so that a desired balance between fuel reduction and reduced driving time is achieved. To calculate fuel consumption, the processor unit is adapted to integrate the predicted fuel flow across the road segment where the speed reduction is to take place, see formulas (13) and (14).

According to one embodiment, the processor unit is adapted to calculate speed setpoints vttf so that the vehicle is calculated to reach the desired set speed vset after passing the road segment to which the input speed vtttt has been lowered, to achieve the desired reduction of vttf.

The reduction of vtttt by using interrupted fuel injection can thus be done by adjusting vtttt so that the desired vstt is reached.

According to one embodiment, the processor unit is adapted to determine the mass of the vehicle, and if the mass of the vehicle exceeds a predetermined threshold value, the processor unit 10 is adapted to calculate a starting position on the horizon for throttling the fuel supply to achieve a reduction to wine. mass is less than or equal to the threshold value, the processor unit is adapted to calculate the reduction of the vehicle speed to achieve a reduction to vim by using Torricelli's equation (1).

According to one embodiment, the processor unit is adapted to calculate threshold values for at least one property on the road segments depending on one or fl your vehicle-specific values, where the threshold values set limits for dividing the road segments into different road classes; compare the slope of each road segment with the threshold values, and classify each road segment on the horizon in a road class according to the comparisons; and calculate speed setpoints vref for the vehicle's control system over the horizon depending on rules linked to the road classes in which the road segments in the horizon are classified. The processor unit is preferably adapted to determine vehicle-specific values through the current gear ratio, current vehicle weight, engine maximum torque curve, mechanical friction and / or the vehicle's estimated driving resistance at current speed.

By adapting the gender resistance, the module can compensate for, for example, headwinds and tailwinds. According to one embodiment, the processor unit is then adapted to adapt the driving resistance by a scale factor by comparing the estimated driving resistance with measured actual driving resistance.

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 method described above, 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 (30)

10 15 20 25 30 21 Patent claims A method for calculating speed setpoints vmf for a control system in a vehicle, k netetec kn ada V that the method comprises: A) determining a horizon using position data and map data of a future road that contains road segments and at least one property for each road segments; B) calculate speed setpoints vref for the vehicle control system over the horizon depending on rules linked to the characteristics of the road segments, and when a reduction of the vehicle's input speed vim to a road segment is considered necessary for the final speed vsluti in the road segment to be 5 vmax, thus avoiding unnecessary braking, so the method comprises: C) calculating a starting position on the horizon when the fuel injection to the vehicle is to be throttled, in order to achieve a reduction to vimi provided that vmin S vfef S vmax, where vmin and vmax set the limits for permitted speeds for vmf, this starting position is included in further calculations of speed setpoints vmf; D) regulate the vehicle according to the speed setpoints vref. Method according to claim 1, which comprises predicting the maximum speed of the vehicle vsluni after the input speed vin, i, and calculating a desired reduction of vim by calculating the speed difference Avm m, = min (vm ,. - VHB-n, vslmi - vw A method according to claim 2, which comprises simulating speed reduction of vmf, wherein the motor torque Tang is set to a small or negative torque, for example towing torque, up to 'Vin', i. A method according to claim 3, comprising calculating the simulated possible deceleration Avpred, i_1 = vslut, i_1 - vpred, i_1, where vpred, i_1 is the predicted final speed in segment (il) with a small or negative motor torque, for example drag torque, and if Avin, tot in Avpmd, i_1, then the starting position for throttling the fuel injection is calculated to: 10 15 20 25 30 22. . VpredJ-l _ AVinJut) .. .. Staríposztzon = -vagsegmentets langa '. AVprezLí-l Method according to claim 4, which comprises that if Avin, tot> Avpred, i_1, and thus the entire desired lowering is not possible under the road segment (i-1), then a new desired lowering Avin, traveled to be Avin, is calculated. tot - Unpred, i_1, after which the existing road segment is examined whether further lowering can be carried out. Method according to 4, which comprises predicting the driving time tT for the vehicle over the road segment, and comparing this driving time tT with the driving time tTOT when the vehicle speed is instead reduced by using Torricelli's equation (1), after which a reduction of the simulated speed is calculated to drive time should be tTOT, to achieve a fuel reduction instead of reduced driving time. A method according to claim 6, which comprises lowering the simulated speed vref so that a desired balance between fuel reduction and reduced driving time is achieved. A method according to claim 6 or 7, which comprises calculating the fuel consumption by integrating the predicted fuel flow across the road segment where the speed reduction is to take place. A method according to any one of the preceding claims, which comprises calculating speed setpoints vref so that the vehicle is calculated to reach the desired set speed after passing the road segment to which the input speed vimi has been reduced, in order to achieve the desired reduction of vmf. A method according to any one of the preceding claims, which comprises throttling the fuel injection by adding vfef to vmin - K, where K is a constant. A method according to any one of the preceding claims, which comprises determining the mass of the vehicle, and if the mass of the vehicle exceeds a predetermined threshold value, then step C) is performed, otherwise the reduction of the vehicle speed is calculated to achieve a reduction to vimi using Torricelli's equation (1). Method according to one of the preceding claims, which comprises: - calculating threshold values for at least one property on the road segments depending on one or fl your vehicle-specific values, where the threshold values set limits for dividing the road segments into different road classes; - compare the slope of each road segment with the threshold values, and classify each road segment on the horizon in a road class according to the comparisons; calculate speed setpoints vmf for the vehicle's control system over the horizon depending on rules linked to the road classes in which the road segments in the horizon are classified. Method according to claim 12, in which vehicle-specific values are determined by the current gear ratio, current vehicle weight, engine maximum torque curve, mechanical friction and / or the vehicle's estimated driving resistance at the current speed. A method according to claim 13, in which the gender resistance is adapted by a scale factor by comparing estimated driving resistance with measured actual driving resistance to compensate for, for example, headwind or tailwind. A module for determining the speed setpoints vmf of a vehicle control system, characterized in that the module comprises a horizon unit adapted to determine a horizon by means of position data and map data of a future road containing road segments and at least one property for each road segment; the module also comprises a processor unit adapted to: - calculate speed setpoints vref for the vehicle's control system over the horizon depending on rules linked to the characteristics of the road segments, and when a reduction of the vehicle's input speed vim to a road segment is considered necessary for the final speed vsluni in the road segment to be S vmax thereby avoiding unnecessary braking, the processor unit is adapted to: - calculate a starting position on the horizon when the fuel injection to the vehicle is to be throttled, to achieve a reduction to vimi provided that Vmin S Vref S vmx, where vmin 10 15 20 25 24 and vninx sets the limits of permissible speeds for vinf, this starting position being taken into account in further calculations of speed setpoints vief; wherein the vehicle is regulated according to the speed setpoints vinf. The module of claim 15, wherein the processor unit is adapted to predict the maximum speed of the vehicle vninni after the input speed vin, i, and calculate a desired reduction of vin, i by calculating the speed difference AvínJat I nun (Vínj _ Vmin 9 Vslulj _ Vmax A module according to claim 16, wherein the processor unit is adapted to simulate speed reduction of vinf, wherein the motor torque Tnng is set to a small or negative torque, for example towing torque, up to vin, i. The module of claim 17, wherein the processor unit is adapted to calculate simulated possible deceleration Avnnni, i_i = vninn i_i - vnnni, i_i, where vnieii, i_i is the predicted final speed in segment (il) with a small or negative motor torque, for example towing torque, and if Avin, nn 5 Avnnni, i_i, then the starting position for throttling the fuel injection is calculated to:. . (AVpredJ-l _ AVínJot .. .. Startposztzon = length of the wagon segment. Avpred, i-1 Module according to claim 18, wherein the processor unit is adapted to calculate if Avin, nn> Avnnni, i_i, which means that the entire desired reduction is not possible under the road segment (il), and further adapted to calculate a new desired reduction Avin in that case. , inn to be Avin, nn - Avpnni, i_i, and investigate whether further lowering can be implemented in the preceding road segment. A module according to claim 18 or 19, wherein the processor unit is adapted to predict the driving time tT of the vehicle over the road segment, and to compare this driving time tT with the driving time tTOT when the vehicle speed is instead reduced by using Torricelli's equation 10 15 20 25 30 25 (1), after which a reduction of the simulated speed is calculated in order for the driving time to be tTOT, in order to achieve a fuel reduction instead of reduced driving time. The module of claim 20, wherein the processor unit is adapted to lower the simulated speed vmf so that a desired balance between fuel reduction and reduced driving time is achieved. A module according to claim 20 or 21, wherein the processor unit is adapted to calculate the fuel consumption by integrating the predicted fuel flow across the road segment where the speed reduction is to take place. A module according to any one of claims 15 to 22, wherein the processor unit is adapted to calculate speed setpoints vref so that the vehicle is calculated to reach the desired set speed after passing the road segment to which the input speed vimi has been reduced, to achieve the desired reduction of vref. A module according to any one of claims 15 to 23, which is adapted to throttle the fuel injection by setting vmf to vmin - K, where K is a constant. A module according to any one of claims 15 to 24, in which the processor unit is adapted to determine the mass of the vehicle, and if the mass of the vehicle exceeds a predetermined threshold value, the processor unit is adapted to calculate a starting position on the horizon for throttling the fuel supply to achieve a reduction to wine , and if the mass of the vehicle is less than or equal to the threshold value, the processor unit is adapted to calculate the decrease in the speed of the vehicle in order to achieve a decrease to vmi by using Torricelli's equation (1). Module according to one of Claims 15 to 25, in which the processor unit is adapted to: - calculate threshold values for at least one property on the road segments depending on one or fl your vehicle-specific values, the threshold values setting limits for dividing the road segments into different road classes; 10 15 20 26 - compare the slope of each road segment with the threshold values, and classify each road segment on the horizon in a road class according to the comparisons; calculate speed setpoints vmf for the vehicle's control system over the horizon depending on rules linked to the road classes in which the road segments on the horizon are classified. Module according to claim 26, in which the processor unit is adapted to determine vehicle-specific values by current gear ratio, current vehicle weight, engine maximum torque curve, mechanical friction and / or the vehicle's estimated driving resistance at current speed. A module according to claim 27, in which the processor unit is adapted to adapt the driving resistance by a scale factor by comparing estimated driving resistance with measured actual driving resistance to compensate for, for example, headwind or tailwind. A computer program product, comprising computer program instructions for causing a computer system in a vehicle to perform the steps of the method according to any one of claims 1 to 13, when the computer program instructions are run on said computer system. The computer program product of claim 29, wherein the computer program instructions are stored on a medium readable by a computer system.