DE102014002998A1 - Method for determining range of motor vehicle, involves determining energy consumption based on vehicle parameters, and implying influence of traffic flow on energy consumption in calculation of range - Google Patents

Abstract

The method involves determining the fuel- or energy amount present in the energy store, and determining the energy consumption of the motor vehicle based on vehicle parameters. A route is determined, along which the mo`tor vehicle is driven. The influence of the traffic flow, which lies ahead of the motor vehicle on the route, on the energy consumption is implied in the calculation of the range. The speed data is received from a central computer.

Description

The invention relates to a method for determining the range of a motor vehicle which has at least one energy store, for example a fuel tank and / or an electrical energy store.

Methods of the type mentioned are known in the art. The determination of the remaining range of a motor vehicle is necessary in order to indicate to the motor vehicle driver which distance he can still cover with the energy available in the motor vehicle. In motor vehicles with liquid or gaseous energy storage can be started in time a gas station, in motor vehicles with only electrical energy storage after exhaustion of the range may be a longer break due to the recharge electrical energy storage has a greater time than refueling a tank with a fuel. As reliable a forecast as possible is therefore crucial.

The range can be calculated essentially from the available amount of energy, for example, the remaining volume of fuel and the expected consumption on the route ahead. The expected consumption depends on a variety of factors. First of all, the driving habits of the driver are important, but also the route type, for example motorway, country road or city, as well as the traffic ahead. Clogging traffic causes frequent braking and acceleration, causing higher consumption compared to constant travel at the same average speed.

From the DE 10 2009 048 821 A1 is a method for range determination for vehicles, in particular electric vehicles known in which besides a characteristic of the energy storage state variable, a further parameter is taken into account. Such a parameter may be, for example, a navigation parameter or a parameter obtained from information relating to a traffic volume in the current environment of the vehicle from a communication device.

However, the prior art has the disadvantage that the resolution of the data is relatively low, whereby the accuracy of the prediction can be too low, especially for electrically powered vehicles.

It is therefore an object of the invention to develop a method of the type mentioned in that a more accurate forecast of the remaining range of a motor vehicle is possible.

The invention is achieved by a method according to claim 1. Further embodiments of the invention subject of the dependent claims.

A method according to the invention for determining the range of a motor vehicle which has at least one energy store provides that a fuel or energy quantity located in the at least one energy store is determined and an energy consumption of the motor vehicle is determined on the basis of vehicle parameters, a route being determined along which will drive the vehicle.

As energy storage tanks for combustion fuels can be used, for example, for liquid or gaseous fuels and / or electrical energy storage, for example, accumulators or other electrical energy storage. Several of these energy stores can be combined in a motor vehicle, for example in a so-called hybrid vehicle.

Vehicle parameters may include, for example, specific fuel consumption, historical fuel consumption, and the driving style of the driver. Furthermore, other typical vehicle parameters are conceivable which relate to the environment of the vehicle and which may have an influence on the consumption. These include, for example, ambient temperature, altitude above sea level or equivalent altitude descriptions etc.

The route can be determined, for example, by means of a navigation system which has a location device, for example GPS, as well as a computing unit, by means of which a route can be calculated. In the context of the invention it can be provided that the route is redetermined and the range of the motor vehicle is recalculated when the driver selects a route other than the stored route.

According to the invention, it is provided that the influence of the traffic flow ahead of the motor vehicle on the route is included in the calculation of the range on the energy consumption. By including the flow of traffic rather than relatively abstract traffic information, a much better determination of the expected consumption can be made since the flow of traffic is a more dynamic statement than a relatively general indication of the traffic condition, which in the prior art knows only several classes of traffic conditions, for example free ones Drive, traffic jam or stagnant traffic.

According to one embodiment of the invention can be provided that expected speeds and / or accelerations to before the motor vehicle lying sections of the route are included in the calculation of energy consumption. With expected speeds and / or accelerations on lying in front of the motor vehicle sections of the route can be made a relatively accurate prediction of the expected energy consumption.

By expressing the traffic flow on the route through speeds and / or accelerations on the route sections of the route, the traffic flow is split up relatively finely.

According to another possible embodiment of the invention can be provided that the expected speeds and / or accelerations are determined by preceding vehicles. By determining speeds and / or acceleration of vehicles in front, the real traffic situation on a route ahead on the route can be determined. For this purpose, real speeds and / or accelerations of the preceding vehicles can be measured and predictions about the expected speeds of the relevant motor vehicle, in which the method according to the invention is performed, can be calculated by means of suitable algorithms. Such algorithms are comparatively robust and reliable, the accuracy increasing with increasing distance or increasing time until reaching the corresponding route section.

According to another possible embodiment of the invention, the speed data and / or acceleration data can be received by a central computer. In such a central computer, the data from a variety of computers and sections can converge. This makes it possible to achieve more accurate forecasts.

Furthermore, in one embodiment of the invention, it may be provided that a speed / acceleration matrix for a section of track ahead is created from the data. Such a speed / acceleration matrix can be well correlated with specific consumptions of the motor vehicle and used to calculate energy consumption.

According to a further aspect, it can be provided that expected speeds and / or accelerations are determined on the basis of historical traffic flows. Such historical traffic flows can be a good indication of how traffic will flow in the absence of special circumstances, such as accidents, at specific times. Thus, in traffic, a different traffic flow is expected than outside such peak hours. The peak times can be well predicted with historical data.

Furthermore, it can be provided that a consumption matrix related to the motor vehicle is used as a function of the speed and / or acceleration of the motor vehicle for calculating the expected consumption. Such a consumption matrix can be predefined and / or currently created or updated. By currently creating a consumption matrix, for example, wear-related influences on the motor vehicle consumption, for example higher internal friction of the engine, condition of the tires and other factors influencing consumption, for example driving with a trailer, used tires, use of a roof box and the like, can be taken into account in the consumption calculation.

Furthermore, it can be provided that speed data and / or acceleration data of the motor vehicle are transmitted to a central computer for a traveled section of the route. In this way, the information of the motor vehicle can be used for further, subsequent motor vehicles for carrying out the same method, which widens the database and increases the reliability of the prediction.

In a further possible embodiment, a geographical profile of the route can be taken into account. Slopes and gradients have a major impact on the expected consumption, since in addition to the pure driving resistance energy may be needed to overcome a height difference.

The invention will be explained with reference to an embodiment. Here are shown schematically:

1 a velocity / acceleration consumption matrix;

2 the matrix out 1 with a graph representing a real journey;

3 the matrix out 1 with a modeling of the energy management of a hybrid vehicle;

4a an acceleration-time diagram of a motor vehicle in real traffic;

4b a speed-time diagram of the same trip;

5a Speed-time diagrams of a first vehicle on a given route as well

5b Speed-time diagrams of a second vehicle on the given route that travels with a certain time offset and

6 shows a flowchart of the method according to the invention.

1 shows a speed / acceleration consumption matrix of a motor vehicle.

On the abscissa the speed is plotted, on the ordinate the acceleration from 6 m / s ² to -6 m / s ² . The consumption of the motor vehicle is shown coded as a point cloud with different brightnesses.

In negative accelerations, ie when braking, the consumption of a motor vehicle is almost zero. For the operation of an internal combustion engine almost no energy is consumed, the energy necessary for the operation of the electrical systems of the motor vehicle can be obtained via the generator from the kinetic energy of the motor vehicle. In accelerations with positive values, energy is consumed and the more, the higher the acceleration. The matrix also shows that consumption increases with increasing speed, so that a graph of constant consumption in a curve of decreasing slope extends from bottom left to top right. This can be recognized by the bright corridor of the matrix.

2 shows the matrix 1 with a graph of a real ride.

The graph is not ambiguous in the diagram because several phases of equal velocity and acceleration can take place at different times and the times in the representation are coded in the length of the graph.

It can be seen that a motor vehicle frequently accelerates and decelerates. By adding or integrating the respective specific consumption, it is possible to determine a total consumption on the route traveled by the motor vehicle.

3 shows a modeling of the energy management of a hybrid vehicle based on the matrix 1 ,

In an area of negative accelerations, an electrical energy store of the hybrid vehicle is charged (recuperated) by converting kinetic energy of the vehicle into electrical energy and storing it in an energy store.

In a range of positive accelerations, but below a certain limit speed - here 40 km / h - an electric drive is loaded and discharged the energy storage for this purpose.

Above 40 km / h, only a conventional drive is actuated, the electrical energy storage is no longer charged. If one overlays a graph of a real journey with the matrix 3 , The energy consumption and the charging of the electrical energy storage can be easily determined and thus determine the state of the electrical energy storage.

In the context of the invention, the method described above is used to determine the future energy consumption by not superimposing a graph of an actual trip with the consumption matrix, but a graph to be expected for the preceding link segment. By correlation with the state of the energy store and the total energy consumption to be expected on the route section determined from the convolution of the graph with the matrix, it can be determined by the method according to the invention which range the motor vehicle has on the current route in the expected traffic volume. The method is thus considerably more accurate than the previously known methods.

The 4a and 4b show acceleration-time diagrams and speed-time diagrams of a particular motor vehicle on a particular stretch of road.

The speed and acceleration data are transmitted to a central computer and used to generate a forecast for subsequent vehicles.

It should be noted that the graph according to 4a by temporal derivation of the graph 4b can be obtained. Thus, in some embodiments of the invention, it may be sufficient to convey only a speed-time relationship.

The 5a and 5b show two speed-time and acceleration-time diagrams of two vehicles that drive at different times on the same stretch of road.

It turns out that the acceleration and speed patterns are very similar, but only temporally offset. This is exemplified by the respective ovals.

From the data of the earlier motor vehicle or of a plurality of earlier motor vehicles, from which average speeds and accelerations are determined, predictions can therefore be made with good reliability about the expected speeds and accelerations of the relevant motor vehicle.

6 shows a flowchart of the method according to the invention.

In a first step, a route is calculated.

In a second step, an amount of energy in the motor vehicle is determined. This can represent the charge capacity of a rechargeable battery, but also the fill level of a fuel tank of a conventional vehicle. In motor vehicles where both types of energy storage are present, both calculations can take place in parallel.

In a third step, a forecast of the speed and / or acceleration course on a preceding route section or a plurality of preceding route sections is retrieved. The steps 2 and 3 can also take place in reverse order.

Subsequently, a consumption matrix is overlaid with an expected speed-time graph. From the overlay, by integrating or summing increments, an expected energy consumption for the route section is calculated. By subtraction with the existing energy storage thus the energy can be calculated after the stretch. This can be done until the calculated storage capacity falls below a limit. The limit can be zero, but it can be above zero if you want to give some buffer. After that, the procedure can be repeated from the beginning.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009048821 A1 [0004]

Claims (10)

A method for determining the range of a motor vehicle having at least one energy storage, in particular a fuel tank and / or an electrical energy storage, wherein one located in the at least one energy storage fuel or energy determined and based on vehicle parameters energy consumption of the motor vehicle is determined, wherein a Route is determined along which the motor vehicle will drive, characterized in that the influence of the lying ahead of the motor vehicle on the route traffic flow on the energy consumption is included in the calculation of the range. A method according to claim 1, characterized in that expected speeds and / or accelerations on lying in front of the motor vehicle road sections of the route are included in the calculation of energy consumption. A method according to claim 2, characterized in that expected speeds and / or accelerations of preceding vehicles are determined. A method according to claim 3, characterized in that the speed data and / or acceleration data are received from preceding vehicles. A method according to claim 3 or 4, characterized in that the speed data and / or acceleration data are received by a central computer. Method according to one of claims 2 to 5, characterized in that a speed / acceleration matrix is created for a route ahead section. Method according to one of claims 2 to 6, characterized in that expected speeds and / or accelerations are determined based on historical traffic flows on the route. Method according to one of the preceding claims, characterized in that a related to the motor vehicle consumption matrix is used in dependence on speed and / or acceleration of the motor vehicle for calculating the expected consumption. Method according to one of the preceding claims, characterized in that speed data and / or acceleration data of the motor vehicle are transmitted for a route section to a central computer. Method according to one of the preceding claims, characterized in that a geographical profile of the route is taken into account.

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