Full speed range adaptive cruise control device, method for controlling a host vehicle speed, road vehicle and computer program

Abstract

The invention is directed to a full speed range adaptive cruise control device (100) for controlling a host vehicle speed (VH) of a host vehicle (300) that comprises a cruise control system (150) configured to implement a limited speed range cruise control (152). It comprises a host vehicle speed determination unit (102) configured to provide a speed signal (SS) indicative of the current host vehicle speed. According to the invention also a transmission control unit (104) is provided configured to provide a transmission closure request (CR) for closing a clutch (162) of the vehicle when the host vehicle speed is below the minimum threshold speed and that an acceleration request (AR) has been provided; and a cruise control reactivation unit (106) configured to receive the current speed signal and to provide a reactivation signal (RS) for activating the limited speed range cruise control when the current host vehicle speed is greater than the minimum threshold speed.

Description

[0001] Hannover, 26.09.2024 IP, Schaferjohann,Nusse / Lu SR 303877-IN-NP EM 303877

[0002] Full speed range adaptive cruise control device, method for controlling a host vehicle speed, road vehicle and computer program

[0003] The present invention relates to a full speed range adaptive cruise control device for controlling a host vehicle speed of a host vehicle that comprises a cruise control system configured to implement a limited speed range cruise control that can be activated when the host vehicle speed is greater than a minimum threshold speed and becomes inactive when the host vehicle speed is lower than the minimum threshold speed. The invention is further directed to a method for controlling a host vehicle speed of a host vehicle that comprises a cruise control system configured to implement a limited speed range cruise control that can be activated when the host vehicle speed is greater than a minimum threshold speed and becomes inactive when the host vehicle speed is lower than the minimum threshold speed. The invention is further directed to a road vehicle and to a computer program.

[0004] Cruise control (CC) is a feature implemented in road vehicles that is used to maintain a host vehicle speed selected by a driver. Adaptive cruise control (ACC) refers to an add on feature to cruise control where the host vehicle speed can be adapted to follow a target vehicle driving in front of the host vehicle at a given distance. Thus, CC provides positive acceleration to maintain or accelerate the host vehicle, wherein ACC controls and / or limits the positive acceleration from the cruise control to reduce the acceleration from the engine. Hence, with respect to engine acceleration, CC acts as a master and the ACC control acts as a slave. Thus, the provision of a CC is mandatory for implementing an ACC, since without an active CC, the ACC cannot maintain or increase the speed.

[0005] Depending on the operating speed range, CC is classified as limited speed range CC or full speed range CC. Conventional CC falls under limited speed range, and can be activated when the host vehicle speed is above a predetermined minimum speed threshold. CC is predominantly used to provide comfort to the driver and to increase fuel efficiency. At low speeds, i.e., host vehicle speed values below the predetermined, non-zero minimum threshold speed, the vehicle is subject to frequent gear shifts and maintaining constant speed at these low speeds is not particularly efficient. Hence, conventional CC, i.e., limited speed range, is not designed to operate at low speeds. With limited speed range CC, ACC can decelerate the host vehicle in the whole speed range, but it can accelerate or maintain the host vehicle speed only above the minimum speed threshold. Recently, original equipment manufacturers are required to extend the operating range of CC to Okm / h at the lower side (until still-stand). This is referred to as full speed range CC, so as to support full speed range ACC (ACC Stop&Go). However, this requires significant changes in the existing CC design. In full speed range ACC, ACC is configured to accelerate from stand-still and at very low speeds. This calls for a dependency to full speed range CC. Thus, full speed range CC is currently a mandatory pre-requisite for full speed range ACC (ACC Stop&Go) and customers having only limited speed range CC cannot be offered ACC Stop&Go capabilities.

[0006] Here is where the invention comes in, where it is an objective of the present invention to address this restriction regarding the use of limited speed range CC to support full speed range ACC.

[0007] This objective is achieved in a first aspect by the invention by a full speed range adaptive cruise control device in accordance with claim 1.

[0008] The full speed range adaptive cruise control device of the first aspect of the invention is configured to control a host vehicle speed of a host vehicle that comprises a cruise control system configured to implement a limited speed range cruise control that can be activated when the host vehicle speed is greater than a minimum threshold speed and becomes inactive when the host vehicle speed is lower than the minimum threshold speed. The full speed range adaptive cruise control device of the first aspect of the invention comprises or is otherwise connected to a host vehicle speed determination unit that is configured to determine a current host vehicle speed of the host vehicle and to provide a current speed signal indicative thereof. The full speed range adaptive cruise control device also comprises a transmission control unit that is configured to receive the current speed signal and to provide a transmission closure request for closing a clutch of the host vehicle upon determining that the host vehicle speed is below the minimum threshold speed and that an acceleration request for increasing the host vehicle speed has been provided. Further, the full speed range adaptive cruise control device comprises a cruise control reactivation unit configured to receive the current speed signal and to provide to the cruise control system a reactivation signal for activating the limited speed range cruise control upon determining that the current host vehicle speed is greater than the minimum threshold speed.

[0009] The full speed range adaptive cruise control device of the first aspect of the invention thus enables to bridge the gap of acceleration between the still stand state of the host vehicle, namely 0 km / h, and the minimum threshold speed. Compared to conventional ACC systems based on limited speed range CC, the full speed range adaptive cruise control device is configured to generate and provide additional signals, namely the transmission closure request to a transmission control unit for closing a clutch, and the reactivation signal to an engine unit operating the limited speed range CC. When the full speed range adaptive cruise control device is instructed to accelerate due to the presence of a corresponding acceleration request, and the host vehicle has a current speed below the predetermined minimum threshold speed, the transmission closure request is generated and provided so that the clutch closes. Once the clutch is starting to close, the host vehicle speed increases. Once the vehicle speed is again above the minimum threshold speed, the reactivation signal is generated and provided so that the limited speed range CO is reactivated. The limited speed range CO can only be activated if the vehicle speed is above said threshold and thus becomes deactivated once the host vehicle speed is reduced below the threshold. Once the CO is reactivated the full speed range adaptive cruise control device acts as a conventional ACC until the host vehicle speed drops below the threshold speed. Once the host vehicle speed drops below the threshold speed, the same cycle continues if there is a request to accelerate.

[0010] Further advantageous developments of the invention are found in the dependent claims and indicate in detail advantageous possibilities to realize the concept described above within the scope of the object as well as with regard to further advantages.

[0011] In the following, developments of the full speed range adaptive cruise control device of the first aspect of the invention will be disclosed

[0012] In a development, the transmission control unit is further configured to cease provision of the transmission closure request upon determining that the host vehicle speed is higher than the minimum threshold speed and that the limited speed range cruise control is reactivated after reception of the reactivation signal. Here, after the cruise control is reactivated, full speed range adaptive cruise control device is configured to stop sending the transmission closure request.

[0013] In another development, the minimum threshold speed is between 10 and 20 km / h, in particularly 15 km / h, in particular with a tolerance of ± 2 km / h, preferably ± 1 km / h.

[0014] In another development the minimum threshold speed depends on a current driving state of the vehicle, in particular on a current load of the vehicle and / or on a current slope of the road. The minimum threshold speed is then a variable whose value changes in dependence on the current state or condition of the vehicle, for example in terms of current load or weight of the loaded vehicle or road conditions, such as slope, adherence, etc.

[0015] To achieve the object, the invention also in a second aspect leads to a method for controlling a host vehicle speed of a host vehicle in accordance with claim 4. The method of the second aspect of the invention is a method for controlling a host vehicle speed of a host vehicle that comprises a cruise control system configured to implement a limited speed range cruise control that can be activated when the host vehicle speed is greater than a minimum threshold speed and becomes inactive when the host vehicle speed is lower than the minimum threshold speed. The method comprises:

[0016] - determining or otherwise ascertaining (e.g., receiving, acquiring, calculating, estimating, etc.) a current host vehicle speed of the host vehicle;

[0017] - providing a current speed signal indicative of the determined current host vehicle speed;

[0018] - upon determining that the host vehicle speed is below the minimum threshold speed and that an acceleration request for increasing the host vehicle speed has been provided, providing a transmission closure request for closing a clutch of the host vehicle;

[0019] - upon determining that the current host vehicle speed is greater than the minimum threshold speed provide to the cruise control system a reactivation signal for activating the limited speed range cruise control.

[0020] The method of the second aspect of the invention thus shares the advantages of the full speed range adaptive cruise control device of the first aspect.

[0021] In the following, developments of the method of the second aspect will be disclosed.

[0022] In a development, the method of the first aspect of the invention further comprises ceasing provision of the transmission closure request upon determining that the host vehicle speed is higher than the minimum threshold speed and that the limited speed range cruise control is reactivated after reception of the reactivation signal.

[0023] To achieve the object, the invention also in a third aspect leads to a road vehicle in accordance with claim 6.

[0024] The road vehicle of the third aspect of the invention comprises a cruise control system that is configured to implement a limited speed range cruise control that is active when the host vehicle speed is greater than a minimum threshold speed and becomes inactive when the host vehicle speed is lower than the minimum threshold speed. The road vehicle also comprises a full speed range adaptive cruise control device in accordance with the first aspect of the invention or any of its developments, and a clutch that is configured to be closed upon reception of the transmission closure request from the transmission control unit of the full speed range adaptive cruise control device. Thus, the road vehicle of the third aspect shares the advantages of the full speed adaptive cruise control device of the first aspect, and / or of the method of the second aspect of the invention.

[0025] A fourth aspect of the invention is formed by a computer program comprising instructions that, when executed by a full speed range adaptive cruise control device cause the full speed range adaptive cruise control device to carry out the method of the third aspect. In particular, the full speed range adaptive cruise control device is a full speed range adaptive cruise control device in accordance with the first aspect of the invention.

[0026] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0027] The embodiments of the invention are described in the following on the basis of the drawing in comparison with the state of the art, which is also partly illustrated. The latter is not necessarily intended to represent the embodiments to scale. The drawing is, where useful for explanation, shown in schematized and / or slightly distorted form. With regard to additions to the teaching immediately recognizable from the drawing, reference is made to the relevant prior art. It should be kept in mind that numerous modifications and changes can be made to the form and detail of an embodiment without deviating from the general concept of the invention. The features of the invention disclosed in the description, in the drawing and in the claims may be essential for a further development of the invention, either individually or in any combination. In addition, all combinations of at least two of the features disclosed in the description, drawing and / or claims fall within the scope of the invention.

[0028] The general concept of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below or to a subject matter, which would be limited in comparison to the subject matter as claimed in the claims.

[0029] For specified design ranges, values within specified limits of the ranges are also disclosed as limit values and thus are arbitrarily applicable and claimable.

[0030] The following drawing shows in:

[0031] FIG. 1 a schematic block diagram of an exemplary full speed range adaptive cruise control device in accordance with an embodiment of the invention;

[0032] FIG. 2 a flow diagram of an exemplary method for controlling a host vehicle speed in accordance with the invention; FIG. 3 a flow diagram of another exemplary method for controlling a host vehicle speed in accordance with the invention;

[0033] FIG. 4 time diagrams indicating the operation of an exemplary full speed range adaptive cruise control device in accordance with an embodiment of the invention;

[0034] FIG. 5 a speed diagram indicating the different operation regimes for a full speed range ACC as a function of the host vehicle speed; and

[0035] FIG. 6 a schematic block diagram of an exemplary road vehicle according to an embodiment of the invention.

[0036] FIG. 1 shows a schematic block diagram of an exemplary full speed range adaptive cruise control device 100 in accordance with an embodiment of the invention. As discussed above, cruise control, also referred to as CC, is a feature implemented in road vehicles that is used to maintain a host vehicle speed VHselected by a driver. In turn, adaptive cruise control, also referred to ACC, is an add on feature to CC where the host vehicle speed VH can be adapted to follow a target vehicle driving in front of the host vehicle at a given distance. The target vehicle is typically the vehicle driving ahead of the host vehicle that implements the CC / ACC system in the same direction and in the same lane. Thus, CC provides positive acceleration to maintain or accelerate the host vehicle, wherein ACC controls and / or limits the positive acceleration from the cruise control to reduce the acceleration from the engine. Hence, with respect to engine acceleration, CC acts as a master and the ACC control acts as a slave, and the provision of a CC is mandatory for implementing an ACC, since without an active CC, the ACC cannot maintain or increase the speed.

[0037] Depending on the operating speed range, CC is classified as limited speed range CC or full speed range CC. Conventional CC falls under limited speed range, and can be activated when the host vehicle speed VH is above a predetermined minimum speed threshold TH. Conventional CC, i.e. , limited speed range, is not designed to operate at low speeds. With limited speed range CC, ACC can decelerate the host vehicle in the whole speed range, but it can accelerate or maintain the host vehicle speed only above the minimum speed threshold.

[0038] The full speed range adaptive cruise control device 100 shown in FIG. 1 is configured to control a host vehicle speed H of a host vehicle 300 (see Fig. 6) that comprises or implements cruise control system 150, which, as discussed above, is configured to implement a limited speed range cruise control 152 that can be activated when the host vehicle speed VH is greater than a minimum threshold speed VTH and becomes inactive when the host vehicle speed VH is lower than the minimum threshold speed VTH.

[0039] The limited speed range cruise control 152 is typically only associated to a limited speed range adaptive cruise control that can control deceleration in the speed range from 0 km / h to the maximum speed (e.g. 150 km / h) but can control acceleration only in the speed range between the minimum threshold speed VTH and the maximum speed. Thus, a limited speed range ACC cannot maintain the speed or accelerate the host vehicles at vehicle speed values below the minimum threshold speed TH. The operation of the limited speed range cruise control 152 for implementing a limited speed range ACC involves the provision of certain signals S1 , S2, S3, TR to given units 154, 156, 158 of the vehicle for providing positive acceleration to maintain or accelerate the host vehicle. The host vehicle includes an engine unit 154 that can be operated by the CC system and that can receive an acceleration request AR. A limited speed range ACC is configured to provide a torque limit request signal S1 for requesting a torque limit at the engine unit 154. The engine unit 154, also referred to as engine control unit (ECU) implements a cruise control system 150. The CC system 150 is configured to provide a torque request TR in order to maintain a selected speed value. The torque value depends on the characteristics of the road, such as the slope, and of the vehicle, such as the load. For instance, the torque value can be selected between 0% (no torque) and 100% (full torque). If no ACC is present or active, the torque request is provided to an engine torque handling unit 157 that controls the provision of the requested torque. When an ACC system is present and active, the ACC system is configured to provide the torque limit request signal S1 , for instance as a requested reduced torque value between 0% and 100%. A decision unit 155 receives the torque request from the CC system 150 and the torque limit request signal, and depending on the respective values, provides a request to the engine torque handling unit. For instance, the decision unit 155 can be advantageously configured to provide the minimum torque value (between 0% and 100%) to the engine torque handling unit 157. Thus, for an inactive ACC system, the torque limit request signal is preferably indicative of a full torque (100%).

[0040] As an example, if based on the road and vehicle conditions, a torque value of 40% is required to maintain the host vehicle speed selected (e.g., by the driver), the CC system 150 provides this value as the torque request TR. If now a slower vehicle is identify driving on the same lane ahead of the host vehicle, the distance between the host and the target vehicle is reduced. If the ACC system is active, it will provide a torque limit request signal in order to reduce the torque and maintain the distance. Once the torque limit request signal is indicative of a value below the one provided by the CC system 150 as a torque request TR, the decision unit will provide the value indicated by the torque limit request signal S1 to the engine torque handling unit 157 and the host vehicle will decelerate accordingly. When the target vehicle is no longer in the same lane ahead (because it has left the road or because the host vehicle has initiated an overtaking maneuver), the torque value indicated by the torque limit request signal increases again, which is understood as an acceleration request AR. Known limited speed range ACC systems can handle this request if the host vehicle speed VHis above the minimum threshold speed VTH- If the host vehicle speed is reduced below this threshold value, the CC system 150, the decision unit 155 and the engine torque handling unit 157 become deactivated.

[0041] The host vehicle also comprises a retarder unit 156. A retarder is a device used to augment or replace some of the functions of primary friction-based braking systems, usually on heavy vehicles. Retarders serve to slow vehicles, or maintain a steady speed while traveling down a hill, and help prevent the vehicle from unintentional or uncontrolled acceleration when travelling on a road surface with an uneven grade. Retarders are not usually capable of bringing vehicles to a standstill, as their effectiveness diminishes as a vehicle's speed lowers. Instead, they are typically used as an additional aid to slow vehicles, with the final braking done by a conventional friction braking system. An additional benefit retarders are capable of providing is an increase in the service life of the friction brake, as it is subsequently used less frequently, particularly at higher speeds. Additionally, air actuated brakes serve a dual role in conserving air pressure. The limited speed range ACC is configured to provide a torque control request signal S2 to the retarder unit 156 for controlling the torque.

[0042] Further, the host vehicle comprises a braking unit 158 (e.g., a pneumatic or hydraulic braking unit). The limited speed range ACC is configured to provide a deceleration request signal S3 to the braking unit 158 for applying the brakes.

[0043] In addition to implementing the limited speed range adaptive cruise control as indicated above, the full speed range ACC device 100 is advantageously configured to bridge the gap that is not operable by the limited speed adaptive cruise control, namely the speed range between stand still (0 km / h) and the minimum threshold speed VTH. This expansion of the operative speed range does not require substantial modification of the CC system, which is still configured as a limited speed cruise control, for speed values ranging between the minimum threshold speed VTH and the maximum speed (e.g. 150 km / h).

[0044] The full speed range adaptive cruise control device 100 of FIG.1 comprises, or is otherwise signally connected to, a host vehicle speed determination unit 102 that is configured to determine a current host vehicle speed VH of the host vehicle and to provide a current speed signal SS indicative thereof. In this particular example, the host vehicle speed determination unit 102 is integrated in the ACC device 100. However, in other examples, the host vehicle speed determination unit is a separate unit signally connected to the ACC device 100. The ACC device 100 also comprises a transmission control unit 104 that is configured to receive the current speed signal SS and to provide a transmission closure request CR for closing a clutch 162 of the host vehicle 300. This is done upon determining that the current host vehicle speed VH is below the minimum threshold speed VTH and that an acceleration request AR for increasing the host vehicle speed VH has been provided or is present. For instance the ACC generates an acceleration request in the form of a torque limit request signal indicative of a higher torque value. Thus, when the host vehicle wants to accelerate (as indicated by the presence of an acceleration request AR) and the host vehicle speed is below the minimum threshold speed VTH, the transmission control unit is configured to provide the transmission closure request CR for closing the clutch 162, which is part of a transmission unit 160 of the host vehicle. Once the clutch starts to close in response to the reception of the closure request, the host vehicle speed increases, in particular so that the host vehicle speed is higher than the vehicle threshold speed.

[0045] Further, the ACC device 100 of FIG. 1 also includes a cruise control reactivation unit 106 that is configured to receive the current speed signal SS and to provide a reactivation signal RS, in particular to the engine unit 154 of the host vehicle, for activating the cruise control system 150, and thus the limited speed range cruise control as explained above. This is done upon determining that the current host vehicle speed VHis greater than the minimum threshold speed VTH- Thus, once the host vehicle speed H increases above the minimum threshold speed VTH, the ACC device 100 is configured to send the reactivation signal RS to the engine unit 154 implementing the CC system 150 to reactivate the limited speed range CC.

[0046] The signals S1 , S2, S3 that are used in the frame of a limited speed range ACC are indicated as dashed arrows, whereas the signals CR, RS that enable the implementation of the full speed range ACC based on a limited speed range CC are indicated as continuous arrows.

[0047] Preferably, in the full speed range adaptive cruise control device 100 of FIG. 1 , the transmission control unit 104 is further configured to cease provision of the transmission closure request CR upon determining that the host vehicle speed VHis higher than the minimum threshold speed VTH and that the limited speed range cruise control is reactivated after reception of the reactivation signal RS.

[0048] Preferably, the minimum threshold speed VTH is between 10 and 20 km / h, in particularly 15 km / h.

[0049] The minimum threshold speed is typically set by the OEM and is it a fixed value associated to the limited speed range cruise control system 150. However, in other examples, the minimum threshold speed VTH can depend on a current driving state of the vehicle, in particular on a current load of the vehicle and / or on a current slope of the road. FIG. 2 shows a flow diagram of an exemplary method 200 for controlling a host vehicle speed VH in accordance with the invention. In particular, the method 200 is suitable for controlling the host vehicle speed VH of a host vehicle 300 (see FIG. 6) that comprises a cruise control system 150 configured to implement a limited speed range cruise control 152 that can be activated when the host vehicle speed H is greater than a minimum threshold speed VTH and becomes inactive when the host vehicle speed VH is lower than the minimum threshold speed VTH. The method 200 comprises, in a step 202, determining or otherwise ascertaining (e.g., receiving, calculating, acquiring, etc.,) a current host vehicle speed VH of the host vehicle. The method 200 also comprise, in a step 204, providing a current speed signal SS indicative of the determined current host vehicle speed VH. The method also comprises, in a step 206, and upon determining that the host vehicle speed VTH is below the minimum threshold speed VTH and that an acceleration request AR for increasing the host vehicle speed has been provided (e.g., a torque limit request signal with an increased torque value), providing a transmission closure request CR for closing a clutch 162 of the host vehicle 300. The method also comprises, in a step 208, and upon determining that the current host vehicle VH speed is greater than the minimum threshold speed VTH, providing a reactivation signal RS for activating the limited speed range cruise control 152.

[0050] Preferably, as indicated by the dashed line, the method 200 further comprises, in a step 210, ceasing provision of the transmission closure request CR upon determining that the host vehicle speed VH is again higher than the minimum threshold speed VTH and that the limited speed range cruise control 152 is reactivated after reception of the reactivation signal RS.

[0051] FIG. 3 shows a flow diagram of another exemplary method 250 for controlling a host vehicle speed in accordance with the invention. When the method 250 is initiated (START), the host vehicle speed VH is checked at step 251. If the host vehicle speed VH is determined to be lower than the minimum threshold speed VTH, the state of the CC is checked at an optional step 252. If the CC is not active, the method checks the presence of an acceleration request AR at step 253. If the AR is present, the method 250 controls the provision of a transmission closure request CR at a step 254 and returns to the initial point (START). If the AR is not present, the transmission closure request is not sent (anymore) at a step 255, and the method returns to the initial point (START).

[0052] If, at step 251 , it is determined that the current host vehicle speed VH is above the minimum threshold speed VTH is higher than the minimum threshold speed VTH, the state of the CC is checked at step 256. If the state of the CC is not active, it is checked at step 257 whether the closure request is currently being provided (as initiated at step 254 under the conditions VH<VTH, CC not active and AR present). If the closure request currently exists, the reactivation signal RS is provided in step 258, and then, when the CC is active again, which is checked at step 259, the provision of the closure request CR and the reactivation signal is stopped, at step 260.

[0053] FIG. 4 shows time diagrams indicating the operation of an exemplary full speed range adaptive cruise control device (e.g. device 100 of FIG. 1) in accordance with an embodiment of the invention. During the time span previous to ti , the host vehicle speed VH remains above the minimum threshold speed VTH and the host vehicle implements the known limited speed range cruise control 152 with the limited speed range ACC, as explained above with reference to FIG. 1 , where the host vehicle speed VH can be controlled to follow the target vehicle speed of a target vehicle driving ahead. Thus, the CC state is active. During this time, an acceleration request AR1 can be handled by the full speed range ACC device 100 in the same way as a regular limited speed range ACC system, resulting in an increase of the host vehicle speed H. At ti , the host vehicle speed VH becomes lower than the minimum threshold speed VTH and the CC state of the limited speed range CC becomes inactive. At t2, a second acceleration request AR2 appears, the acceleration request being indicative of a request to increase the speed of the host vehicle. In known limited speed range ACC systems, this request would be ignored, since it appears at a point where the host vehicle speed is below the minimum threshold speed VTH- However, the full speed range ACC device 100 is advantageously configured to, upon determining the presence of the acceleration request AR2 (at VH<VTH), provide a transmission closure request CR for closing the clutch of the host vehicle. When the clutch is closed, the host vehicle begins to accelerate (t2). At the instant t3, the host vehicle speed VH is again above the minimum threshold speed VTH, and the ACC device 100 is configured to provide an reactivation signal RS for reactivating the CC system, i.e. to cause the CC system to be active again. This happens at t4in response to the provision of the reactivation signal at t3. Once the CC status is active again (t4), the provision of the transmission closure request CR and of the reactivation signal RS ceases, and the host vehicle is operated again in accordance with the limited speed range cruise control 152 as explained above.

[0054] Following the discussion of FIG. 4, at instant t5the host vehicle speed VHis again lower than VTH, which caused the CC state to become inactive. This time the speed is reduced until the vehicle is in a still stand state (VH = 0 km / h). At instant te, a new acceleration request AR3 is present, and the ACC device 100 provides the transmission closure request, that causes clutch 162 to close and the host vehicle increases its speed VH. At instant t?, the host vehicle speed VH is again higher than the minimum threshold speed VTH, and the ACC device 100 provides the reactivation signal RS. Once the CC status is active again (at instant ts), the provision of the transmission closure request CR and the reactivation signal RS ceases. FIG. 5 shows a speed diagram indicating the different operation regimes for a full speed range ACC as a function of the host vehicle speed VH. The limited speed range cruise control system of the host vehicle is operable at host vehicle speeds between the minimum threshold speed (e.g., 15 km / h) and the CC maximum speed (e.g., 150 km / h). At these speeds, the acceleration of the vehicle is performed by the limited speed range CC system as explained for instance with reference to Fig. 1. In order to implement a full speed range ACC, the acceleration of the host vehicles at speeds between 0 and the minimum threshold speed is performed by the transmission control unit, upon reception of a transmission closure request CR for closing the clutch and enable the acceleration of the host vehicle.

[0055] FIG. 6 shows a schematic block diagram of an exemplary road vehicle 300 according to an embodiment of the invention. The road vehicle 300 carries a certain load W and is driving on a road 302, having a given slope G. The road vehicle comprises a full speed range adaptive cruise control device 100b according to the invention, in which, in contrary to the ACC device 100 of FIG. 1 , the host vehicle speed determination unit 102 configured to determine a current host vehicle speed VH of the host vehicle 300 and to provide a current speed signal SS indicative thereof is an external unit. The vehicle 300 comprises an engine unit 154, a retarder unit 156, a braking unit 158 and a transmission unit 160 that comprises the clutch 162, as explained with reference to FIG. 1 above. The ACC device 100b is configured to provide the signals S1 , S2, S3 to the engine unit 154, the retarder unit 156 and the braking unit 158 respectively, for implementing a known limited speed range adaptive cruise control, as explained with reference to FIG. 1. The ACC device 100b is further configured to operate as a full speed range adaptive cruise control device for accelerating the host vehicle also at host vehicle speeds VHthat are lower than the minimum threshold speed VTH, by providing the transmission closure request CR to the transmission unit 160 for closing the clutch 162 and by providing the reactivation signal RS, as explained in detail above, for instance with respect to FIG. 4.

[0056] Preferably, in the full speed range adaptive cruise control device 100, 100b the minimum threshold speedTH is between 10 and 20 km / h, in particularly 15 km / h. However, in another exemplary full speed range adaptive cruise control device, the minimum threshold speed VTH depends on a current driving state W of the host vehicle 300, in particular on a current load W of the vehicle 300 and / or on a current slope G of a road 302.

[0057] In summary, the invention is directed to a full speed range adaptive cruise control device for controlling a host vehicle speed of a host vehicle that comprises a cruise control system configured to implement a limited speed range cruise control, comprising a host vehicle speed determination unit configured to provide a current speed signal indicative of the current host vehicle speed, a transmission control unit configured to provide a transmission closure request for closing a clutch of the vehicle when the host vehicle speed is below the minimum threshold speed and that an acceleration request has been provided; and a cruise control reactivation unit configured to receive the current speed signal and to provide a reactivation signal for activating the limited speed range cruise control when the current host vehicle speed is greater than the minimum threshold speed.

[0058] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0059] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0060] A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0061] Any reference signs in the claims should not be construed as limiting the scope.

[0062] REFERENCE LIST (PART OF THE DESCRIPTION)

[0063] 100 Full speed range adaptive cruise control device

[0064] 100b Full speed range adaptive cruise control device

[0065] 102 Host vehicle speed determination unit

[0066] 104 Transmission control unit

[0067] 106 Cruise control reactivation unit

[0068] 150 Cruise control system

[0069] 152 Limited speed range cruise control

[0070] 154 Engine unit

[0071] 155 Decision unit

[0072] 156 Retarder unit

[0073] 157 Engine torque handling unit

[0074] 158 Braking unit

[0075] 160 Transmission unit

[0076] 162 Clutch

[0077] 200 Method

[0078] 202-210 Method steps

[0079] 250 Method

[0080] 251-260 Method steps

[0081] 300 Host vehicle

[0082] 302 Road

[0083] AR Acceleration request

[0084] CR Transmission closure request

[0085] G Slope of road

[0086] RS Reactivation signal

[0087] 51 Torque limit request signal

[0088] 52 Torque control request signal

[0089] 53 Deceleration request signal

[0090] SS Current speed signal

[0091] TR Torque request

[0092] VH Host vehicle speed

[0093] VTH Minimum speed threshold

[0094] W Load of vehicle

Claims

CLAIMS1. Full speed range adaptive cruise control device (100, 100b) for controlling a host vehicle speed (VH) of a host vehicle (300) that comprises a cruise control system (150) configured to implement a limited speed range cruise control (152) that can be activated when the host vehicle speed (VH) is greater than a minimum threshold speed ( TH) and becomes inactive when the host vehicle speed ( H) is lower than the minimum threshold speed (VTH), the full speed range adaptive cruise control device (100) comprising:- a host vehicle speed determination unit (102) configured to determine a current host vehicle speed (VH) of the host vehicle (300) and to provide a current speed signal (SS) indicative thereof; characterized in that the full speed range adaptive cruise control device (100) further comprises:- a transmission control unit (104) configured to receive the current speed signal (SS) and to provide a transmission closure request (CR) for closing a clutch (162) of the host vehicle (300) upon determining that the current host vehicle speed (VH) is below the minimum threshold speed (VTH) and that an acceleration request (AR) for increasing the host vehicle speed (VH) has been provided; and- a cruise control reactivation unit (106) configured to receive the current speed signal (SS) and to provide a reactivation signal (RS) to the cruise control system (150) for activating the limited speed range cruise control (152) upon determining that the current host vehicle speed (VH) is greater than the minimum threshold speed (VTH).

2. The full speed range adaptive cruise control device (100, 100b) of claim 1, wherein the transmission control unit (104) is further configured to cease provision of the transmission closure request (CR) upon determining that the host vehicle speed (VH) is higher than the minimum threshold speed (VTH) and that the limited speed range cruise control (152) is reactivated after reception of the reactivation signal (RS).

3. The full speed range adaptive cruise control device (100, 100b) of claim 1 or 2, wherein the minimum threshold speed (VTH) is between 10 and 20 km / h, in particularly 15 km / h.

4. Method (200, 250) for controlling a host vehicle speed (VH) of a host vehicle (300) that comprises a cruise control system (150) configured to implement a limited speed range cruise control (152) that can be activated when the host vehicle speed (VH) is greater than a minimum threshold speed (VTH) and becomes inactive when the host vehicle speed (VH) is lower than the minimum threshold speed (VTH), the method comprising:- determining (202) a current host vehicle speed (VH) of the host vehicle (300);- providing (204) a current speed signal (SS) indicative of the determined current host vehicle speed (VH);- upon determining that the host vehicle speed (VH) is below the minimum threshold speed (VTH) and that an acceleration request (AR) for increasing the host vehicle speed (VH) has been provided, providing (206) a transmission closure request (CR) for closing a clutch (162) of the host vehicle;- upon determining that the current host vehicle speed ( H) is greater than the minimum threshold speed (VTH), providing (208) to the cruise control system (150) a reactivation signal (RS) for activating the limited speed range cruise control (152).

5. The method (200, 250) of claim 4, further comprising:- ceasing (210) provision of the transmission closure request (CR) upon determining that the host vehicle speed (VH) is higher than the minimum threshold speed (VTH) and that the limited speed range cruise control (152) is reactivated after reception of the reactivation signal (RS).

6. Road vehicle (300) comprising:- a cruise control system (150) configured to implement a limited speed range cruise control (152) that is active when the host vehicle speed (VH) is greater than a minimum threshold speed (VTH) and becomes inactive when the host vehicle speed (VH) is lower than the minimum threshold speed (VTH);- a full speed range adaptive cruise control device (100, 100b) in accordance with any of the preceding claims 1 to 3;- a clutch (162) configured to be closed upon reception of the transmission closure request (CR) from the transmission control unit (104) of the full speed range adaptive cruise control device (100, 100b).

7. Computer program comprising instructions that, when executed by a full speed range adaptive cruise control device (100, 100b) cause the full speed range adaptive cruise control device (100, 100b) to carry out the method of any of the claims 4 or 5.

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