Method and system for switching operations from a first gear ratio to a second gear ratio in a vehicle

Abstract

Method for use in a shifting operation from a first gear ratio to a second gear ratio in a vehicle (100), wherein the vehicle (100) comprises an internal combustion engine (101) and a transmission (103) which is adjustable in a series of fixed gear ratios J, J=1,2,...,m, for the transmission of a force between the internal combustion engine (101) and at least one drive wheel (113, 114), wherein in operation the engine speed of the internal combustion engine (101) is controlled such that it maintains a first engine speed (N kalib ) does not exceed, whereby the procedure then applies when switching from a first lower translation J i to a second, higher translation J i-k , k≥2, is required to drive the vehicle (100) without slowing down the vehicle (100), includes: - Determination of whether the engine speed (n) of the internal combustion engine (101) is sufficient after a shift operation to the second gear ratio J i-k, the first engine speed (N kalib ) exceeds, characterized in that - if the engine speed (n) of the internal combustion engine (101) is the first engine speed (N kalib ) after a shift to the second gear J i-k exceeds, execution of a switching operation to the second translation J i-k , so that the engine speed (n) of the internal combustion engine (101) after a shift operation to this gear ratio J i-k the first engine speed (N kalib exceeds, - Determination of whether the engine speed (n) of the internal combustion engine (101) is sufficient after a shift operation to the second gear ratio J i-k , below the first engine speed (N kalib ) falls within a first period (tlim1), and - Performing a switching operation to the second translation J i-k only if the engine speed (n) of the internal combustion engine (101) is below the first engine speed (N) kalib) falls within the first period (tlim1).

Description

Field of invention

[0001] The present invention relates to the driving of a vehicle and in particular to a method for use in connection with shifting operations from a first gear ratio to a second gear ratio according to the preamble of claim 1. The invention further relates to a system and a vehicle as well as a computer program product that implement the method according to the invention. Background of the invention

[0002] Regarding vehicles in general, there are a number of different powertrain configurations. The transmission, for example, can be a manual gearbox or an automatic transmission. With regard to trucks, it is often desirable for them to be as comfortable as possible for the driver, which usually means that gear changes should be performed automatically with the help of the vehicle's controls. Automatic transmissions have therefore become increasingly common in trucks.

[0003] Automatic transmissions in trucks often consist of a control unit that manages the gear changes in "manual" transmissions, meaning transmissions with one set of gears per gear, where the ratios are divided into a suitable number of fixed gear ratios. This type of transmission, called AMT (Automated Manual Transmission), often has the advantage of higher efficiency compared to conventional automatic transmissions. Furthermore, its use is frequently advantageous from a cost perspective.

[0004] When operating vehicles of the aforementioned type, it is often desirable to achieve the smoothest possible gear changes. This means that the drive force in the powertrain during the shift and the associated interruption of drive force are controlled in such a way as to prevent any unwanted jerking. At the same time, it is often desirable for gear changes to be performed with a relatively short interruption of drive force, especially when driving uphill, to prevent the vehicle from losing too much speed during the shift. Furthermore, when driving uphill, particularly when the vehicle is heavily loaded, it is often important that the vehicle's transmission is set to a gear ratio that provides sufficient drive force to ensure that the vehicle does not slow down undesirably when that gear is engaged.

[0005] The vehicle therefore loses speed during a downshift when driving uphill. For a short time after the gear is engaged, the vehicle's speed continues to decrease. This is a result of the engine's torque increasing after the shift, from the lower torque present during the shift itself to the drive torque required to propel the vehicle in the selected gear. The vehicle thus continues to slow down as the torque increases until it reaches the drive torque. Once the drive torque is reached, the vehicle continues to travel in the selected gear without deceleration. This means that, if the correct gear has been selected, the gear ratio provides sufficient driving power to prevent the vehicle from slowing down. Thus, a balance of forces is achieved.Force compensation and thus a constant vehicle speed prevail until the vehicle's operating conditions change, e.g., if the road gradient changes.

[0006] DE 10 2007 027 134 A1 discloses an engine control unit. The engine control unit and a transmission control unit exchange signals and binary data via a communication link. The electronic engine control unit records current operating parameters and, depending on these parameters, performs a soft or hard speed limiting function. Upon detecting a critical downshift due to over-revving, the transmission control unit transmits a warning signal via the communication link to the electronic engine control unit, prompting the electronic engine control unit to perform a soft speed limiting function.

[0007] DE 601 02 962 T2 discloses a system for preventing maximum engine speeds for automatic transmissions of motor vehicles with an engine control unit that detects the current engine speed and engine load from the outputs of an engine speed sensor and an accelerator pedal travel sensor. Brief description of the invention

[0008] An object of the present invention is to provide a method in connection with a shifting operation to a lower gear, i.e., a higher gear ratio, when driving a vehicle, particularly on an incline. This object is achieved by a method according to claim 1.

[0009] The present invention specifically relates to a method in connection with a switching operation from a first gear ratio to a second gear ratio in a vehicle, wherein the vehicle comprises an internal combustion engine and a transmission which can be set in a series of fixed gear ratios J, J=1,2,...,m, for the transmission of a force between the internal combustion engine and at least one drive wheel, wherein in operation the engine speed of the internal combustion engine is controlled such that it does not exceed a first engine speed.

[0010] The procedure includes, when a switching operation from a first lower gear ratio J i to a second, higher translation J i-k , k≥2, is required to drive the vehicle without slowing down the vehicle: - Determining whether the engine speed (n) of the internal combustion engine exceeds the first engine speed after the shift to the second gear ratio J i-k, and, - if the engine speed of the internal combustion engine is the first engine speed after a shift to the second gear J i-k exceeds, execution of a switching operation to the second translation J i-k , so that the engine speed of the internal combustion engine corresponds to the gear ratio J after the shifting process. i-k , exceeds the first engine speed.

[0011] The translation J=1,2,...,m thus represents an increase from the first translation (J=1) to the second translation (J=m).

[0012] As mentioned above, trucks often use the type of transmission normally found in manual vehicles, but the shifting is performed automatically by the vehicle's control system. By definition, a shift from one gear to another in this type of transmission involves disengaging the drivetrain when the prevailing gear is disengaged and re-engaging it when a new gear is selected. However, before the drivetrain re-engages, the engine speed must be synchronized with the expected rotational speed of the transmission's input shaft when the new gear is engaged to prevent unwanted jolts or fluctuations associated with the shift. Overall, this means that a shift requires a certain amount of time followed by an interruption of power delivery.

[0013] In the context of trucks, this means that the interruption of drive power during a gear change, especially when occurring on an incline, can result in a downshift to the immediately following higher gear ratio (i.e., the gear directly below the current gear), causing such a drop in speed that completing a downshift to the next lower gear becomes unsafe. Trucks often have transmissions where a relatively large number of gear ratios can be selected, such as 10 to 20. When a truck is traveling on a surface such as a road that transitions into an incline, several downshifts are often necessary.Several gear changes increase the gear ratio to obtain a driving force equal to or exceeding the braking force (driving resistance) acting on the vehicle. If a gear change is not performed using at least the highest gear (lowest gear ratio), the vehicle will slow down due to insufficient driving force. This gear is referred to herein as the equalizing gear. Therefore, if a gear change is performed to a gear directly above the equalizing gear (shifting to a ratio directly below the equalizing gear), it is not guaranteed that a shift to the equalizing gear will be possible due to the loss of speed associated with the shift and if too high a gear is engaged.These circumstances may make it necessary to shift down to a significantly lower gear to ensure that the vehicle does not slow down to the point of coming to a standstill.

[0014] Generally, it is often desirable to drive the vehicle in as high a gear as possible (i.e., in the lowest possible gear ratio), as this is often advantageous from a fuel consumption perspective, for example. Accordingly, it is desirable not to downshift to a gear that is too low, which often results in increased fuel consumption and greater vehicle deceleration.

[0015] According to the present invention, a method is provided which enables the switching process to the force compensation gear in earlier phases than previously possible, thereby reducing the risk of an undesirably large deceleration.

[0016] In connection with vehicles in general, a maximum engine speed has been specified, which differs from the physical maximum engine speed of the internal combustion engine, i.e., the maximum engine speed at which the engine can run. This specified maximum engine speed of the vehicle's internal combustion engine can be considerably lower than the physical maximum engine speed and is often regulated by the vehicle's control system and not exceeded during operation. This specified maximum engine speed can also be speed-dependent and / or gear-dependent and therefore differ for different speeds / gears.According to the present invention, this limitation, which is set by the control unit, is overcome during downshifting, and all engine speeds up to the physical maximum engine speed or another suitable engine speed below the physical maximum engine speed but above the set maximum engine speed are permitted. The application determines whether the engine speed of the internal combustion engine exceeds the set maximum engine speed after a shift to the power-balancing gear. Furthermore, according to the invention, a shift to the power-balancing engine is executed if the engine speed exceeds the set maximum engine speed after such a shift.

[0017] According to the present invention, it is determined whether the engine speed of the internal combustion engine falls below the specified maximum engine speed again within a first period after a shift operation to the second gear ratio, wherein the shift operation is only carried out if the engine speed falls below the specified maximum engine speed within the first period.

[0018] According to one embodiment, it is determined whether the engine speed of the internal combustion engine exceeds the specified maximum engine speed by a maximum value of a first engine speed difference after a shift operation, wherein the shift operation to the second gear ratio is only carried out if the engine speed exceeds the maximum engine speed by the first engine speed difference after the shift operation.

[0019] As discussed above under the heading "Background of the Invention," the criterion relating to the first period or the criterion relating to the first engine speed difference is thus fulfilled when the selected gear achieves a power equalization at a level below the first engine speed sufficiently quickly. Once the power equalization is achieved, the vehicle is driven without slowing down.

[0020] The method according to the present invention can be implemented, for example, with the aid of one or more processors, one or more field-programmable gate arrays (FPGAs) and / or one or more application-specific integrated circuits (ASICs).

[0021] Further features of the present invention and related advantages are described in detail in the exemplary embodiments shown below and in the accompanying drawings. Brief description of the drawings Fig. Figure 1 shows a schematic representation of a vehicle in which the present invention can be used. Fig. shows a control device in the control system for the in Fig. Vehicle shown. Fig. Figure 1 shows a schematic representation of a scenario in which a vehicle is driving and in which the present invention can be applied. Fig. shows a first exemplary method according to the present invention. Fig. shows an example dependency for a maximum engine speed in an internal combustion engine. Fig. illustrates an embodiment according to the exemplary method described in Fig. is shown. Fig. shows a second exemplary method according to the present invention. Fig. illustrates an embodiment according to the exemplary method described in Fig. is shown. Fig. shows a schematic representation of a switching process according to the invention in the scenario described in Fig. is shown. Detailed description of the embodiments

[0022] The term "transmission" in the present description and in the following claims refers to a mechanism that, taken as a whole, enables the setting of various gear ratios that can be selected and are available while the vehicle is being driven. The transmission as such may comprise several separately controlled transmission parts, such as a main transmission and, for example, a range and / or a branch transmission. The gear ratios referred to below consist of ratios that can be selected, for example, in a range or branch transmission. In general, a shift to a lower gear results in a shift to a higher gear ratio, i.e., a shift from a first lower gear ratio to a second higher gear ratio. The engine speed increases while the vehicle speed remains unchanged.

[0023] Fig. Figure 1 shows a schematic representation of a drive train in a vehicle 100 according to an embodiment of the present invention. The vehicle 100, which is shown in the schematic representation in Fig. The powertrain shown comprises an internal combustion engine 101, which is connected in the usual manner to a transmission 103 via a clutch 106 through an output shaft on the internal combustion engine 101, typically via a flywheel 102. The internal combustion engine 101 is controlled by the vehicle 100 via a control device 115.

[0024] An output shaft 107 from transmission 103 drives the drive wheels 113, 114 via a final drive 108, such as a conventional differential shaft, and the drive shafts 104, 105, which are connected to the final drive 108. The in Fig. The illustrated shifting system consists of a type with an automatic transmission, meaning that gear selection is controlled by the vehicle's control unit. The transmission's function is controlled and monitored by a control device 116, which can also be designed to control the clutch 106, which can thus be an automatically controlled clutch. The present invention can, for example, be implemented in the control device 115 and / or the control device 116.

[0025] In conjunction with automatic transmissions, gear selection, i.e., the selection of the gear ratio for the setting in transmission 103, is controlled by the vehicle's control unit, allowing suitable gear strategies to be applied so that the internal combustion engine operates as desired. Gear selection can be designed to be controlled by various criteria, and the correct gear selection can be more or less critical depending on the current situation of the vehicle.

[0026] An example of a situation where gear selection is particularly critical is when trucks are driving uphill. When driving vehicles uphill, it is generally important, and especially for trucks, that the vehicle's gear is set to one that allows the vehicle to climb the hill. If the transmission is set to too high a gear (a gear ratio that is too low), the available driving force will not be sufficient for the vehicle to maintain its speed, meaning the vehicle will slow down. To prevent the vehicle from losing speed, a force balance must generally be achieved; that is, the driving force delivered by the internal combustion engine must be at least equal to the force acting on the vehicle in the opposite direction of travel.

[0027] Depending on the prevailing load of the vehicle 100, the gradient of the surface, and the prevailing speed of the vehicle 100, the highest gear for which a power balance can be achieved—i.e., the highest gear in which the vehicle 100 can be driven without undesirable deceleration—can vary. This is in Fig. illustrated by example. Fig. The change in road gradient is shown as a percentage for a road segment, with the road up to position S. A is essentially horizontal (the road gradient is essentially zero degrees), and the road gradient then begins to increase until position S B to increase a first derivative, whereby the change in road gradient up to position S C the gradient changes more rapidly until the maximum slope is reached. The gradient then decreases until position S. Dmaintain where the road begins to flatten out, in order to stay at position S E to transition to an essentially horizontal road.

[0028] Fig. The highest gear, indicated by a dashed line, represents a power-compensating gear for the respective road sections; that is, a gear in which the vehicle can be driven at 100 km / h under the prevailing conditions without slowing down due to a lack of sufficient driving power. The change in the power-compensating gear is shown very schematically and, as can be seen in this figure, it can change more or less continuously with changes in the road gradient and changes in the vehicle's speed. The in Fig. The example shown only illustrates the principle that the maximum possible power compensation rate decreases when the road gradient increases and increases when the road gradient decreases. The actual relationship between the power compensation rate and the road gradient can differ considerably in practice from that shown in the example. Fig. The example shown differs, e.g., due to the vehicle weight, the road gradient, changes in vehicle speed, when overcoming the gradient, etc.

[0029] According to the in Fig. In the example shown, vehicle 100 can be driven with the highest gear m engaged until the road gradient reaches a certain gradient α. m reached, whereby, when the vehicle is approximately at position S 100 A reached, the highest gear that allows driving without slowing down the vehicle at 100 km / h, gradually up to gear J. xThe total number of gear ratio steps J can be any number and, in trucks as described above, can consist of, for example, 10 to 20 adjustable gear ratio steps. As the terrain flattens, the vehicle can be driven in a similar manner in an increasingly higher gear (reducing the gear ratio).

[0030] When driving uphill, it is therefore important not to drive in a higher gear than possible to avoid slowing down if maintaining a constant speed is desired. A problem, particularly with trucks, is that gear changes take time and consequently cause a loss of speed. Furthermore, the more gear changes are performed, the greater the speed loss due to interruptions in power delivery. It is therefore crucial to select gears that minimize the vehicle's slowdown when climbing an incline.

[0031] As discussed above under the heading "Background of the Invention," the vehicle thus travels without deceleration when the balancing force for an engaged gear prevails. If the gear ratio is too low, the vehicle slows down, and a downshift is necessary to achieve a new force balance at a lower constant speed. During the shifting process itself and for a short time afterward, the vehicle slows down until its engine torque reaches the relevant torque and the force balance following the shift is achieved.

[0032] Furthermore, downshifting on an incline should often be done with at least two gears simultaneously, as downshifting by just one gear can lead to such a significant reduction in speed that shifting to the next gear becomes impossible. Therefore, it is crucial that downshifting is performed correctly. For example, if a shift is made to a gear above the leveling gear, shifting to this higher gear (which is not a leveling gear) can cause the vehicle to lose so much speed during the shift, due to the incline and the vehicle's weight, that it becomes impossible to shift into the highest possible gear. Fig. to shift gears. This can in turn mean that a shift to a gear one or more steps below the desired gear must be carried out in order to then, if possible, accelerate again and subsequently shift up to the desired gear via one or more gear ratio steps. It is desirable to avoid such situations, and the present invention provides a method that enables a direct shift to a gear below the desired gear in a large number of situations.

[0033] An exemplary embodiment 300 according to the present invention is described in Fig. illustrated and begins at step 301, and the illustrated procedure can be implemented, as described above, in a suitable control device in the vehicle's control system, such as control device 116.

[0034] Generally, control systems in modern vehicles consist of a communication bus system comprising one or more communication buses for connecting a number of electronic control units (ECUs), such as the control devices or controllers 115, 116, and various components located in the vehicle. Such a control system can comprise a large number of control devices, and responsibility for a specific function can be distributed across more than one control device. However, the invention can be implemented in a control device specifically designed for the present invention or wholly or partially in one or more other control devices already present in the vehicle. For the sake of simplicity, it is shown Fig. only the control devices 115, 116.

[0035] According to the present invention, the function of the control device 116 (or the control device(s) in which the present invention is implemented) can depend, for example, on signals from the control device 115 in conjunction with, for example, the status of the clutch / transmission. Similarly, signals can be output to the control device 115. The control of the control device 116 can also depend on information related to the prevailing driving resistance. According to the prior art, there are several ways to calculate the driving resistance of the vehicle and the highest possible gear in which the vehicle can be driven without slowing down at a given driving resistance. This can be designed to be calculated by the control device 116, or alternatively, the control device can be designed to receive such data from another control device.In general, control devices of the type shown are normally designed to receive sensor signals from various parts of the vehicle as well as from various control devices present on the vehicle.

[0036] The control system is often programmed by programmed instructions. These programmed instructions typically consist of a computer program which, when executed in a computer or control device, causes the computer / control device to perform the desired control action as a process step in the process according to the present invention.

[0037] The computer program usually consists of a part of a computer program product, the computer program product being a suitable storage medium 121 (see Fig. The computer program is stored on the storage medium 121. The computer program can be stored on the storage medium in a non-volatile manner. The digital storage medium 121 can, for example, consist of any device from the following group: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash, EEPROM (Electrically Erasable PROM), a hard disk device, etc., and it can be installed in or in combination with the control device, with the computer program being executed by the control device. By changing the instructions of the computer program, the behavior of the vehicle can thus be adapted in a specific situation.

[0038] An exemplary control device (the control device 116) is shown in Fig. schematically represented. The control device can in turn comprise a computing device 120, which may consist, for example, of a suitable processor or microcomputer type, such as a digital signal processor (DSP) or an application-specific integrated circuit (ASIC). Computing device 120 is connected to a storage device 121, which supplies the computing device 120 with, for example, the stored program code and / or data required by the computing device 120 to perform calculations. Computing device 120 is also configured to store intermediate or final results of calculations in storage device 121.

[0039] Furthermore, the control device is equipped with devices 122, 123, 124, 125 for receiving and transmitting input and output signals. These input and output signals can contain waveforms, pulses, and other characteristics that are determined as information by devices 122, 125 for receiving input signals and can be processed by computing device 120. Devices 123, 124 for transmitting output signals are designed to convert the calculation result of computing device 120 into output signals for transmission to other parts of the vehicle control system and / or the component(s) for which the signals are intended. Each of these connections to the devices for receiving and transmitting input and output signals can consist of one or more cables, a data bus, such as...a CAN bus (Controller Area Network), a MOST bus (Media Oriented Systems Transport) or any other bus configuration or wireless connection.

[0040] Referring to Fig. An exemplary embodiment 300 according to the present invention is illustrated. In step 301, it is determined whether the vehicle is being driven on an incline. As long as this is not the case, the method remains at step 301, whereas, if it is determined that the vehicle is being driven on an incline, the method proceeds to step 302. The transition from step 301 to 302 may, for example, depend on whether the vehicle's driving resistance is equal to a certain suitable driving resistance and / or whether the road incline is at least partially equal to a certain gradient, such as a suitable degree or a certain percentage gradient, where such a gradient may be a function of the vehicle's weight, since the vehicle's driving resistance, i.e.,the sum of external forces that must be overcome to accelerate the vehicle or to maintain a constant speed, which represents the sum of rolling, air and gradient resistance forces, depends strongly on the vehicle weight and the road gradient.

[0041] The vehicle's rolling resistance is frequently estimated, for example, in connection with gear changes in trucks, and also, for example, when using look-ahead cruise control functions. As experts know, rolling resistance can be estimated in a number of suitable ways, and such an estimation is therefore not described here in full detail. Road gradient can likewise be estimated in several ways according to the state of the art, alternatively by using, for example, a gradient sensor, and it also represents an important parameter in determining rolling resistance.

[0042] The transition from step 301 to step 302 can, for example, also be based on other suitable criteria. The vehicle can, for instance, be designed to constantly determine the highest gear in which the vehicle can be driven without undesirable deceleration, and the transition from step 301 to step 302 can be controlled, for example, by the fact that the vehicle is driven in a gear several steps above the highest gear the vehicle can drive at a constant speed. Alternatively, the method can be designed to begin directly at step 302. The transition from step 301 to step 302 can also be designed to depend on the prevailing speed of the vehicle, with the present invention being designed to be applied only when the speed of the vehicle falls below a certain applicable speed (below the maximum speed of the vehicle), e.g.,For example, because of the risk that a failed gear shift will cause the vehicle to come to a standstill, which is greater at lower vehicle speeds compared to higher vehicle speeds.

[0043] Step 302 determines whether downshifting to a lower gear is necessary, for example, whether downshifting is required to maintain the vehicle's speed as described above. If no downshifting is required, the procedure returns to step 301, while if step 302 determines that downshifting is necessary, the procedure proceeds to step 303. Step 303 determines whether downshifting by several gears is required, which is referred to as the power-compensating gear J. kjv (defined by the dashed line in Fig. or Fig. can be defined two or more steps below the prevailing gait Ji (defined by the continuous line in Fig. , whereby step 303 determines whether this is the case. According to one embodiment, step 303 also determines whether the vehicle's speed is below a first speed. In the event of a failed downshift at lower speeds, there is a greater risk that the vehicle will be forced to stop, and for this reason, according to one embodiment, the invention is only applied if the vehicle's speed is below the first speed, which may consist of a suitable relatively low speed. According to one embodiment, step 303 can thus determine whether the vehicle has to perform a critical shift operation, whereby a failed shift operation into the equalization gear can lead to the risk that the vehicle will have to be stopped.If the condition(s) in step 303 is / are not met, the procedure continues with step 311, where the usual downshifting to a suitable gear is performed. This is in conjunction with the determination of the prevailing power-balancing gear J. kjv In accordance with the state of the art, such a determination as described above is carried out on a large scale, especially for trucks, e.g. by estimating the driving resistance and knowledge of the driving force that can be delivered at different gears / engine speeds, and this determination can thus be carried out in a suitable manner.

[0044] If the force compensation gear J kjv at least two steps below the prevailing aisle J i If this is the case, the procedure continues with step 304. In step 304, it is determined whether, after a switching operation into the force compensation gear J, kjv the expected engine speed of the internal combustion engine N kjva calibrated, fixed maximum engine speed N kalib exceeds. In general, internal combustion engines in vehicles of the illustrated type are limited in the sense that there is a specified maximum engine speed that must not be exceeded during operation. The engine speed N kalib The engine speed can be set, for example, according to the torque characteristics of the internal combustion engine. The engine speed is therefore a speed limited by the vehicle's control system and is not exceeded during operation. The maximum engine speed setting is not changed during operation.

[0045] This specified maximum engine speed can be designed to consist of a fixed engine speed, but the engine speed can also consist of an engine speed that depends on the vehicle speed and / or gear. This type of "floating" engine speed is found in trucks. This dependence of the vehicle's specified maximum engine speed can, for example, depend on the Fig. of the type shown, where the y-axis represents the engine speed and the x-axis represents the vehicle speed, which in this case decreases in the direction of the x-axis. Trucks can be designed so that, as in Fig. Illustrates the maximum engine speed N V1 at a speed V1 less than a maximum rotational speed N V2at a speed of V2, where V2 is a lower speed compared to V1. The reason for this might be, for example, that improved handling at lower vehicle speeds is desired. Connections of the type described in Fig. The illustrated shift points can be designed individually for each gear and can be configured to apply only to specific gears and a specific portion of the vehicle's speed range. However, a calibrated, fixed engine speed is always used. According to the current state of the art, shifting into a gear while exceeding the specified maximum engine speed of the internal combustion engine (regardless of whether this is speed-dependent or not) is not permitted.

[0046] In step 304, as described above, it is determined whether the engine speed N kjvfor the power differential J kjv presumably the engine speed N kalib exceeds what can be determined as a function of the expected vehicle speed after a shift operation. If this is not the case, i.e., if the expected engine speed is below the permissible maximum engine speed, the procedure continues with step 308, where a shift operation to the power compensation gear J is performed. kjv is executed directly. This is done in Fig. illustrates a situation according to the situation in Fig. shows, and where in Fig. The actual shifting process and therefore the predominant gear is represented by a continuous line. Fig. This shows the engine speed. During a shift between SA and SB, the engine speed does not rise above neutral. kalibIn this case, a downshift comprising at least two steps is therefore performed directly to the power compensation gear, thus avoiding undesirable deceleration due to the intermediate downshift to the power compensation gear. According to one embodiment, a transition from step 304 to step 308 only occurs if the expected engine speed exceeds a suitable minimum engine speed to ensure that the engine speed after the shift is sufficiently high for the desired driving characteristics.

[0047] If the expected engine speed N kjv on the other hand the engine speed N kalib exceeds the amount associated with N kjv at time t gc in Fig. and also S C in Fig. As illustrated, the procedure continues with step 305. According to the prior art, in this case a shift to an intermediate gear necessarily occurs, resulting in a reduction in speed, and there is a risk that a subsequent shift to the power-compensating gear will no longer be possible due to the additional reduction in speed combined with additional shifting operations. According to the present example, such problems are reduced by determining in step 305 whether the engine speed is expected to decrease during the shift to the power-compensating gear J. kjv , in the example with J x at time S C shown, below the specified maximum engine speed N kalib within an initial period T lim1 falls. This is in Fig. This is illustrated where the x-axis represents time and the y-axis represents the rotational speed of the combustion engine.

[0048] Furthermore, line 501 shows the expected speed of the internal combustion engine during a shift to the power equalization gear J. kjv Line 502 shows the specified maximum permissible engine speed during normal operation according to Fig. As in Fig. As shown, the engine speed is expected to change after the shift into the power compensation gear J. kjv decreases because the engine speed is expected to decrease over time according to line 501. Similarly, the expected maximum engine speed, line 502, increases because the vehicle speed is expected to decrease. As discussed above under the heading "Background of the Invention," the vehicle speed decreases until its engine reaches the operating torque for the selected gear and force equalization is achieved. This is also in Fig. illustrates where the engine speed of the internal combustion engine is shortly after the shifting process at S Cback below engine speed N kalib falls.

[0049] Assuming that a switching operation occurs at time T gc in Fig. The expected engine speed of the internal combustion engine after the switching process is N. kjv considerably higher than the permissible engine speed. However, in step 305 it is determined whether the engine speed of the internal combustion engine 101 is expected to decrease to the permissible engine speed, represented by line 502, within a first period T. lim1 decreases. This is in Fig. than the time until the intersection point T int This illustrates where the engine speed of the internal combustion engine 101 is expected to be equal to the permissible engine speed and will subsequently fall below it. The time T lim, can be defined as any suitable period of time, such as a suitable number of seconds or milliseconds. Thus, if in step 305 it is determined that the engine speed of the internal combustion engine 101 is expected to change within the time T lim1 If the engine speed falls below the permissible limit, the procedure continues with step 306, while otherwise it continues with step 309.

[0050] Step 306 determines whether the expected engine speed after the switching operation N kjv below a physical engine speed limit N lim falls. The engine speed N limThis consists of a maximum engine speed, which is limited, for example, by design and / or structural constraints. In the case of internal combustion engines, there is usually an engine speed that should never be exceeded due to the risk of damage, etc. However, this engine speed is typically considerably higher than the specified maximum permissible engine speed during operation N. kalib as described above. In step 306, it is ensured that this engine speed, in conjunction with shifting operations to the power compensation gear J, is maintained. kjv is never exceeded. Alternatively, step 306 can determine whether a switching operation to force compensation gear J is required. kjv This results in the internal combustion engine speed exceeding another suitable engine speed, thereby exceeding the normally permissible maximum engine speed. If, in step 306, it is determined that the expected engine speed N kjv the maximum engine speed Nlim If the speed exceeds the expected engine speed N, the procedure can, for example, be designed to remain at step 306 until the vehicle speed has decreased to such an extent that the expected engine speed N kjv after the switching process to force compensation gear J kjv below the threshold engine speed N lim is. If the engine speed N is subsequently expected to be kjv below the maximum engine speed N lim If the procedure falls, it continues with step 307, where a switching operation to force compensation gear J takes place. kjv is carried out. The described method thus enables a switching process to force compensation gear J. kjv in situations where this was previously not possible.

[0051] If, in step 305 above, it is determined that the engine speed of the internal combustion engine during the shifting process to the power compensation gear J kjv not below the calibrated engine speed N kalibwithin the period T lim1 If the road surface falls, the procedure continues with step 309, where it is determined whether a shift is still required. If not, the procedure returns to step 301, which might be the case, for example, if the road surface levels out again. If, on the other hand, it is determined that a shift is still required, a shift with fewer steps, according to the normal shift logic, becomes gear J. kjv+k performed in step 310. In cases where the current gear is at least three gear ratios above the force compensation gear J. kjv For the reasons above, a gear shift is preferentially performed in gear J. kjv+k , k≥2, performed, i.e. at least two steps above the force compensation step, with one switching operation to the force compensation step J kjv then in a further translation step according to the invention, where applicable.

[0052] According to the in Fig. The example shown illustrates a switching process for force compensation J. kjv in cases where the engine speed of the internal combustion engine 101 is expected to fall below a calibrated, fixed maximum engine speed during a first period T lim1 falls. According to a second embodiment, the engine speed of the internal combustion engine 101 does not have to drop to the calibrated maximum engine speed within a first period after the switching process. Fig. Figure 600 shows a second method 600 according to the invention, wherein steps 601-604, 608, 611 correspond to steps 301-304, 308, 311 in Figure 600. Fig. are equivalent to.

[0053] If in step 604 it is determined that the engine speed after a shift operation into the power compensation gear J kjv greater than the engine speed N kalibIf the procedure is successful, it continues with step 605, where it is determined whether the engine speed of the internal combustion engine is affected after the shift to the power compensation gear J. kjv below engine speed N kalib , plus a certain suitable engine speed N Δ , falls. Where this is the case, a switching operation becomes a force compensation gear J. kjv in step 606. If this is not the case, steps 609-610 are executed, which correspond to steps 309-310 in Fig. correspond. That in Fig. The described procedure is in Fig. The example shows where line 701 represents the engine speed of the internal combustion engine after the shift to the power compensation gear J. kjv and line 702 the calibrated maximum engine speed for gear J kjv as described above. As in Fig. As can be seen, the lines do not intersect, but it is expected that the engine speed of the internal combustion engine 101, at least during the displayed time period, will be the calibrated maximum engine speed N. kalib exceeds. According to the in Fig. However, in the illustrated embodiment, this is permissible according to the present invention as long as the motor speed difference N Δ below a suitable threshold N thres remains.

[0054] According to the in Fig. In the illustrated embodiment, the vehicle can thus be driven at a higher engine speed of the internal combustion engine than the calibrated maximum engine speed N. kalib This is permitted as long as the vehicle is driven on the incline, or until, for example due to a change in road gradient, it is determined that a shift into another gear is appropriate. According to one embodiment of the invention, the engine speed difference N Δapplied together with another criterion, which results in the motor speed difference N Δ It must be designed so that, over time, after a switching operation, it transitions to the force compensation mode J. kjv reduced, as e.g. according to Fig. According to this embodiment, a gear shift will only be performed when the vehicle is driven at a higher engine speed of the internal combustion engine than the calibrated maximum engine speed N. kalib , if the engine speed of the internal combustion engine 101 changes over time in the direction of engine speed N after the switching process kalib is decreasing.

[0055] In summary, the present invention provides a method that allows a shifting operation to a desired gear at an earlier stage than is possible according to the prior art, thereby avoiding the risk of having to shift to a lower gear compared to the power compensation gear with the associated acceleration and subsequent upshifting.

[0056] It should also be noted that the system can be modified according to different embodiments of the method according to the invention (and vice versa), and the present invention is in no way limited to the embodiments of the method according to the invention described above, but relates to and includes all embodiments within the scope of the accompanying independent claims.

Claims

[1] Method for use in a shifting operation from a first gear ratio to a second gear ratio in a vehicle (100), wherein the vehicle (100) comprises an internal combustion engine (101) and a transmission (103) which is adjustable in a series of fixed gear ratios J, J=1,2,...,m, for the transmission of a force between the internal combustion engine (101) and at least one drive wheel (113, 114), wherein in operation the engine speed of the internal combustion engine (101) is controlled such that it maintains a first engine speed (N kalib ) does not exceed, whereby the procedure then applies when switching from a first lower translation J i to a second, higher translation J i-k , k≥2, is required to drive the vehicle (100) without slowing down the vehicle (100), includes: - Determination of whether the engine speed (n) of the internal combustion engine (101) is sufficient after a shift operation to the second gear ratio J i-k, the first engine speed (N kalib exceeds, characterized by , that - if the engine speed (n) of the internal combustion engine (101) is the first engine speed (N kalib ) after a shift to the second gear J i-k exceeds, execution of a switching operation to the second translation J i-k , so that the engine speed (n) of the internal combustion engine (101) after a shift operation to this gear ratio J i-k the first engine speed (N kalib exceeds, - Determination of whether the engine speed (n) of the internal combustion engine (101) is sufficient after a shift operation to the second gear ratio J i-k , below the first engine speed (N kalib ) falls within a first period (tlim1), and - Performing a switching operation to the second translation J i-k only if the engine speed (n) of the internal combustion engine (101) is below the first engine speed (N) kalib) falls within the first period (tlim1). [2] Method according to claim 1, wherein the second translation J i-k represents a translation in which the vehicle (100) can be driven without slowing down. [3] Method according to claim 1 or 2, wherein the second translation J i-k represents the lowest gear ratio at which the vehicle (100) can be driven without slowing down. [4] Method according to any one of claims 1-3, further comprising: - Determining the lowest gear ratio after a gear shift, which is the gear ratio at which the vehicle (100) can be driven without slowing down, where the second gear ratio J i-k as the aforementioned lowest translation. [5] Method according to any one of claims 1-4, further comprising performing a switching operation from the first translation directly to the second translation J i-k, where the second translation J i-k a translation that represents at least two translation steps from the first translation J i is removed. [6] Method according to any one of claims 1-5, wherein the first motor speed (N kalib ) exceeds a specified first maximum engine speed for the second gear ratio. [7] Method according to claim 6, wherein the first motor speed (N kalib ) represents a speed-dependent rotational speed, wherein the maximum rotational speed differs according to the speed of the vehicle for at least part of the vehicle's speed range. [8] Method according to one of the preceding claims, wherein the first motor speed (N kalib ) represents an engine speed that is below a maximum engine speed determined for reasons of physical, design and / or strength limitations. [9] A method according to any of the preceding claims, further comprising: - Determination of whether the engine speed (n) of the internal combustion engine (101) is sufficient after a shift operation to the second gear ratio J i-k , the first rotational speed (N kalib ) by a maximum value of a first engine speed difference (N Δ ) exceeds, and - Performing a switching operation to the second translation J i-k only if the engine speed (n) of the internal combustion engine (101) after the shifting process to the second gear ratio J i-k the first engine speed (N kalib ) to a maximum value of the first engine speed difference (N Δ\ ) exceeds. [10] The method of claim 9, further comprising: - Performing a switching operation to the second translation J i-k only if the engine speed (n) of the internal combustion engine (101) after a shift operation to the second gear ratio J i-kover time in the direction of the first engine speed (N kalib ) decreases. [11] Method according to any of the preceding claims, further comprising carrying out the switching operation to the second translation J i-k , when the vehicle (100) is on an incline. [12] Method according to any of the preceding claims, further comprising performing a shift operation to the second gear ratio only when the speed of the vehicle is below a first speed, wherein the first speed is below the maximum speed of the vehicle. [13] Computer program comprising program code which, when executed in a computer, causes the computer to execute the method according to any one of claims 1-12. [14] Computer program product comprising a computer-readable medium and a computer program according to claim 13, wherein the computer program is contained in this computer-readable medium. [15] System for the switching operation from a first gear ratio to a second gear ratio in a vehicle (100), wherein the vehicle (100) comprises an internal combustion engine (101) and a transmission (103) which is adjustable in a series of fixed gear ratios J, J=1,2,...,m, for the transmission of a force between the internal combustion engine (101) and at least one drive wheel (113, 114), wherein, in operation, the engine speed of the internal combustion engine (101) is controlled such that it maintains a first engine speed (N kalib ) does not exceed, wherein the system includes elements which, when used to drive the vehicle without slowing down the vehicle (100) in conjunction with a shift operation from a first lower gear ratio i to a second higher gear ratio J i-k, k≥2, is required : - Determine whether the engine speed (n) of the internal combustion engine (101) is the same after a shift operation to the second gear ratio J i-k , the first engine speed (N kalib exceeds, characterized by , that - if the engine speed (n) of the internal combustion engine (101) is the first engine speed (N kalib ) after a shift to the second gear J i-k exceeds, execution of a switching operation to the second translation J i-k , so that the engine speed (n) of the internal combustion engine (101) after a shift operation to this gear ratio J i-k the first engine speed (N kalib exceeds, - Determine whether the engine speed (n) of the internal combustion engine (101) is the same after a shift operation to the second gear ratio J i-k , below the first engine speed (N kalib ) falls within a first period (tlim1), and - a shift operation to the second translation J i-k only to be carried out if the engine speed (n) of the internal combustion engine (101) is below the first engine speed (N) kalib ) falls within the first period (tlim1). [16] Vehicle (100), characterized by that it comprises a system according to claim 15.

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