CN109416401B

CN109416401B - Vehicle, continuously variable transmission system, control method, and computer program product

Info

Publication number: CN109416401B
Application number: CN201780040495.2A
Authority: CN
Inventors: E·范维克; P·W·C·范德摩特勒
Original assignee: Nanjing Bangqi Automatic Transmission Co ltd
Current assignee: Nanjing Bangqi Automatic Transmission Co ltd
Priority date: 2016-04-28
Filing date: 2017-04-28
Publication date: 2024-01-30
Anticipated expiration: 2037-04-28
Also published as: BE1023741B1; CN109416401A; WO2017186911A1

Abstract

A Continuously Variable Transmission (CVT) system for a vehicle includes a transmission having two friction elements. The first friction element is coupled to the second friction element by a torque transmitting member, wherein a clamping force or pressure of at least one friction element on the torque transmitting member is adjustable. The CVT system further comprises a controller for retrieving information indicative of an upcoming road condition, wherein the controller is further arranged for adjusting the clamping force or pressure of the at least one friction element on the torque transmitting member based on the retrieved information.

Description

Vehicle, continuously variable transmission system, control method, and computer program product

Technical Field

The present invention relates to a system and method for controlling a vehicle transmission through the use of acquired road condition information.

Background

Vehicle transmissions provide for controlled application of engine power through speed and torque conversion from a power source. A Continuously Variable Transmission (CVT) is an automatic transmission that allows for a change through a continuous range of effective gear ratios. The input from the prime mover may be used to deliver variable output speed and torque, while the input may be maintained at a constant angular velocity. The CVT may include a transmission for providing mechanical power transfer, where the transmission may include two friction elements, where a first friction element is connected to a second friction element by a torque transfer member, such as a (thrust) strap. A first conical pulley and a second conical pulley may be provided, each pulley being connected to the shaft. Each shaft may include a fixed sheave and an axially movable sheave. A flexible member such as, but not limited to, a chain or a belt strip may be arranged, wherein the belt strip may be a segmented steel V-belt clamped between two pairs of tapered sheaves of a pulley, wherein the gap between the pulleys and thereby the running radius of the belt strip may be adjusted by axial movement of the movable sheaves. The transmission can change its gear ratio steplessly.

The efficiency of a CVT may be primarily affected by mechanical system efficiency, actuation system losses, and control strategies. When the vehicle is traveling at a constant medium speed, the actuation system will take up most of the power consumption and also have a significant impact on the efficiency of the transmission. If the clamping force in the transmission is reduced, the efficiency of the transmission may be increased and the power required to actuate the system may be reduced, resulting in an increase in the efficiency of the CVT. Clamping forces in the transmission are also important to mechanical system efficiency. Thus, reducing the clamping force will at least partially reduce both the actuation system losses and the mechanical system losses.

CVT efficiency has reached the level of Manual Transmission (MT), but there is still room for improvement, as the losses of today's CVT may be higher compared to the losses of MT. The primary reason for the lower efficiency of a CVT is the high clamping force required to transmit engine torque. To prevent torque transmitting members or straps from slipping, the clamping force in a CVT is typically always higher than required for "normal" operation, i.e., without disturbances and/or torque peaks. Thus, higher clamping forces may cause higher losses in both the hydraulic and mechanical systems, for example, due to increased pump losses, and additional mechanical loads on the transmission components result in increased friction losses. Higher clamping forces also reduce the durability of the strap due to increased wear, as the net tension in the element is greater than strictly required (for normal operation). Likewise, due to the clamping force, heavier components may be required and thus arranged in the CVT system, which may also have an adverse effect on the power density.

Thus, the clamping force of the torque transmitting members (e.g., push belt) has a significant impact on the efficiency of the CVT. In fact, the efficiency of a CVT depends largely on the clamping force. Thus, lower clamping forces may result in better efficiency.

Reducing transmission clamping forces is advantageous for fuel consumption due to reduced power consumption by the hydraulic pump of the CVT and reduced frictional power losses in the parts of the transmission. The reduced clamping force also contributes to the power density, since the stress of the thrust belt is reduced. However, reduced clamping forces also increase the risk of belt slip, for example in the case of torque peaks or in the case of slow or delayed hydraulic responses.

In order to be able to cope with the undesirable torque peaks resulting from driving on roads with severe and/or different road conditions, a higher clamping force may be employed as the minimum value required to avoid belt slip. Such precautions are necessary because the road conditions of the vehicle are unknown. However, if such over-clamping is not used in a CVT, the disturbance situation may result in a severe slip event, which may damage the CVT's transmission. It is known to use a measure of the actual torque or slip in the transmission in order to use a clamping force with a lower safety margin, i.e. to reduce the clamping force and/or not to excessively clamp, while reducing the risk of excessive slip. .

Moreover, in the known CVT control system, the control system may also use a sensor for measuring the wheel speed or acceleration, so as to appropriately adjust the clamping force.

US2005/159,259 discloses a method for detecting road irregularities by means of a gradient of the sum difference between a measured wheel speed and a weighted average of the wheel speeds, whereby the contact pressure on the sheaves of a transmission is adjusted on the basis of the detected road conditions. In such feedback control systems, detection of road irregularities may come too late, so that in "normal" driving conditions (e.g., driving conditions without road irregularities), the clamping force needs to be large enough to resist undesirable sustained high shock and/or torque peaks due to the vehicle traveling over the road irregularities. In practice, in a feedback control system using the wheel speed, an event on the wheel is detected. However, there is no guarantee that the event on the wheels is due to road irregularities. The wheel speed event is related to a road condition. Although the control system may be implemented with relatively simple means, the accuracy and certainty provided tends to be limited.

Disclosure of Invention

It is an object of the present invention to provide a system, method and vehicle which obviate at least one of the above disadvantages while maintaining the advantages.

It is a further object of the present invention to improve the efficiency of a CVT system and/or a vehicle comprising the CVT system.

It is another object of the present invention to provide an efficient control strategy for a CVT in which the risk of slip in the transmission of the CVT, such as slipping of torque transmitting members such as thrust belts in the transmission (known as "belt slip"), is reduced when the vehicle encounters different road conditions.

The CVT system may include a transmission having two friction elements, with a first friction element coupled to a second friction element by a torque transfer member. The clamping force or pressure of at least one friction element on the torque transmitting member is adjustable. The CVT system further comprises a controller arranged for retrieving information indicative of an upcoming road condition. Furthermore, the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member based on the retrieved information.

The information representing the road condition may relate to a road condition such as mountain information, weather conditions, snow, rain, a gradient of the ground or road, objects on the road, pits, curbs, road irregularities, road surfaces, road flatness, traffic, etc. It should be appreciated that the information representative of the road condition may include a numerical value for the road condition. The information representing the road condition may also be encrypted or encoded. The information representing the road condition may also include a classification of the road condition. The road condition information herein refers to information indicating a road condition unless otherwise specified.

In the transmission, power may be transmitted from the first pulley to the second pulley through the torque transmitting member. The torque transmitting member may be a thrust belt arranged between the first pulley and the second pulley, wherein power is transmitted by means of friction between the thrust belt and the pulley sheaves. Thus, using upcoming road condition information retrieved by the controller, increased efficiency may be obtained through control of the pressure or clamping force of the torque transmitting members or thrust bands for the CVT.

As already mentioned, the efficiency of a CVT transmission is largely dependent on the clamping force of the torque transmitting members (e.g., thrust bands). Optimizing to the lowest non-slip clamping force results in lower hydraulic pressures. However, in order to be able to cope with the undesired torque peaks generated by different road conditions, higher clamping forces are generally employed to obtain the minimum clamping force required to avoid the strip slipping when different road conditions are encountered. Higher clamping forces may adversely affect efficiency, resulting in higher fuel consumption of the vehicle. According to the invention, the road condition of the upcoming vehicle is retrieved by the controller. Thus, the (relevant) road conditions to be experienced by the driven wheels of the vehicle and thus the CVT can be predicted and processed to evaluate the effect on the CVT system of the vehicle before actually experiencing the effect. For example, an upcoming road condition ahead of a vehicle comprising a forward movement of the CVT system may be used to pre-determine (related) the road condition and consider the retrieved road condition to increase the clamping force or pressure of at least one friction element on the torque transmitting member if needed. As a result, the use of a general backup, safety margin, or excessive clamping force or pressure may be avoided or at least greatly reduced, which may increase the efficiency of the CVT system. Another advantage is that the risk of adverse effects such as belt slip in CVT systems can be reduced, which can improve service life and/or reduce maintenance costs.

Thus, instead of using direct and feedback for detection of slip conditions, for example, when the wheels of the running vehicle reach a depression on the road, the road surface condition may be identified beforehand by the controller, so as to predict the required clamping force, and if necessary, the clamping force is adjusted in advance of or simultaneously with the road condition experienced, so as to avoid slipping of the belt in the CVT.

Optionally, the controller is arranged to predict a change in input and/or output torque of the transmission based on the retrieved road condition information and to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member according to the predicted torque change. The adjustment of the clamping force or pressure in the transmission may be performed before or simultaneously with the torque change.

As a result, an evaluation of the road condition related to the vehicle can be obtained in advance. For example, information about road irregularities and/or road flatness on the road may be detected prior to the impact event, so that the clamping force can be increased in time. In this way, the vehicle may be configured to employ a lower clamping force during "normal" driving conditions, which may result in reduced fuel consumption of the vehicle. Driving comfort can also be improved. Furthermore, wear may be reduced, thereby also increasing the service life of the vehicle and its components.

Thus, if the road condition of the driving route of the vehicle is predicted and/or expected by the vehicle, a higher clamping force including a reserved amount can be avoided. To achieve this, road conditions are obtained in advance. The controller may then analyze the retrieved data to identify and take into account the road conditions ahead.

Optionally, the controller is arranged to predict a moment in time at which a change in transmission input and/or output torque will be transmitted based on the retrieved road condition information, and to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member in accordance with the predicted torque change. The adjustment of the clamping force or pressure in the transmission may be performed before or at the predicted moment.

A vehicle including the CVT according to the invention can employ a lower reserved amount and can also maintain a lower reserved amount, so that efficiency losses can be avoided. This effect can be particularly profound when the vehicle is traveling under normal road conditions, while the clamping force or pressure in the transmission is a common reserve or safety margin to be arranged to handle undesirable torque peaks. The controller of the CVT system may be arranged to perform a pre-control of the clamping force or pressure in the transmission before the impact occurs to ensure that the required clamping level is reached at or even before the impact occurs. Advantageously, a post-control of the clamping force or pressure in the transmission after the impact has occurred can also be performed by the controller, so as to ensure that the required clamping force level or pressure level in the transmission remains sufficiently long, for example, so as to prevent slipping of the belt strips due to the disappearance of the torque oscillations.

Optionally, the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member if the predicted change in transmission input and/or output torque exceeds a predetermined threshold level.

Optionally, the controller is arranged for retrieving road condition information from a detector for detecting road conditions.

The upcoming road condition may be determined from data obtained, for example, by a detector of a substantially non-invasive remote sensing system for identifying relevant road condition features. The detector may be a sensor system comprising one or more sensors configured to sense information about the environment in which the vehicle is located or other information that may be important to the vehicle, such as future road condition information in a future path of the vehicle (in driving). In this way, changing road conditions can be identified in time. While the detector may be arranged to obtain road condition information of the (related) upcoming vehicle, said information may also be obtained from a memory, a network, a data transmission, a cloud, other vehicles, other entities, and/or as a sensor system for other systems, e.g. as a sensor for providing autonomous capabilities for an autonomous vehicle. Thus, the controller may dynamically adjust actuation of friction elements of a transmission of the CVT based on the acquired upcoming road condition information. In addition, the remote sensing system provided from the detector and the data from the cloud may be used in order to better predict the road condition of the vehicle.

Optionally, the detector is arranged for determining a road condition in front of the vehicle.

Optionally, the detector is placed in a vehicle. For example, the detector may be arranged at the front of the vehicle in order to provide front detection.

Optionally, the controller is arranged for wireless communication connection to the detector. The detector may be disposed in or on the vehicle while in wireless communication with the controller. However, alternatively or additionally, the upcoming road condition information may be retrieved from a detector arranged on another structure.

A wireless communication system may be arranged to provide wireless communication between the controller and the detector. The controller may be configured to be wirelessly coupled to one or more other vehicles, sensors, or other entities, either directly or via a communication network. To this end, the wireless communication system may include an antenna and chipset for communicating with other vehicles, sensors, or other entities, either directly or through a wireless interface. A chipset or wireless communication system may generally be arranged to communicate in accordance with one or more other types of wireless communications (e.g., protocols), such as bluetooth, communication protocols described in IEEE802.11 (including any IEEE802.11 revisions), cellular technologies (e.g., GSM, CDMA, UMTS, EV-DO, wiMAX, or LTE), zigbee, dedicated Short Range Communications (DSRC), and Radio Frequency Identification (RFID) communications, among other possibilities. The wireless communication system may take other forms as well.

Optionally, the controller is arranged for communication with a detector placed in another vehicle, preferably traveling in front of the vehicle comprising the continuously variable transmission system.

Optionally, the controller is arranged for communication with a detector, the detector being placed stationary relative to the road.

Optionally, the controller is arranged for communicating with a network to retrieve road condition information.

Data from sensors on the vehicle that facilitate obtaining an assessment of local road conditions may be communicated with a cloud or other networked system to build a road condition database of the road. This data may then be used by other vehicles that may access the cloud. Furthermore, direct communication between different vehicles is possible, thereby obtaining an improved and/or faster view of the road conditions associated with the vehicles. Moreover, the previous data may be stored locally and/or in the cloud, thereby improving the efficiency of determining the road condition.

In an advantageous embodiment, the road condition information may be stored in a cloud and/or server so that appropriate information about local and global road conditions, whether the next vehicle, a local server connected to a central database, or an internet server, can be summarized and provided or shared to the outside world. Advantageously, information taken by the controller from the cloud can be used in conjunction with a detector to increase the level of grip of the CVT transmission, if necessary or desired. The communication may be by any telecommunication device and is for example standard, protocol, where information may be sent and received from local servers and other vehicles as well as local measuring devices on the road (side). The local server may collect information about the local roads. The local server may be connected to a global server, collecting road data for a larger area, wherein some data analysis algorithms may be used to more accurately determine road condition data and the impact on the vehicle in use with respect to clamping forces. The types of information that may be exchanged between the vehicle and the cloud may be: GPS location, weather conditions, road type, IRI classification, objects (e.g., potholes, curbs, etc.), object features (height, width, location), camera pictures, wheel speed information, tire pressure information, accelerometer sensor information, internal CVT speed sensor information, clamping force information, etc. Many other possibilities are possible. In some examples, the data may be aggregated for communication.

Optionally, the network comprises a memory storing road condition information.

Optionally, the network is in communication with one or more detectors arranged for determining road conditions, the one or more detectors being placed stationary relative to the road and/or within the vehicle.

Optionally, the system comprises a network server arranged for providing road condition information to the controller. The network server may be arranged for receiving an indication of the location of the controller from the controller and for communicating road condition information relating to the location of the controller to the controller.

Optionally, the detector comprises an optical system, such as a digital camera, a radar system, a lidar system and/or an acoustic system.

The detector may be a substantially non-invasive remote sensing system arranged at least partly in front of the vehicle, so as to define at least a scanning field in front of the vehicle or at least in front of driven wheels of the vehicle, i.e. the direction of travel of the vehicle. It should be appreciated that fields other than the front field may be arranged, such as lateral, bottom, rear and/or 360 deg. fields. The detector may be a remote sensing system comprising a camera. The acquired data from the camera, radar, lidar and/or acoustic sensor inputs may be used to predetermine road conditions to increase system pressure in the CVT when the detected road conditions require. Under normal road conditions, the vehicle may travel with the system pressure of the CVT kept relatively low, such that unnecessary pressure reserves are not required, thereby reducing or avoiding efficiency losses associated with the use of pressure reserves.

Optionally, the controller is arranged for analyzing an image provided by the camera for a feature indicative of a road condition.

Features that indicate road conditions may include: mountain information, weather conditions, snow, rain, slope of the ground or road, objects on the road, potholes, curbs, road irregularities, road surface, road flatness, etc. This feature may be associated with control of clamping force or pressure in the transmission of the CVT system.

The camera may be any camera (e.g., still camera, video camera, etc.) configured to capture an image of an environment or surrounding area in which the vehicle is located. To this end, the camera may be configured to detect visible light, or may be configured to detect light from other parts of the spectrum, such as infrared or ultraviolet light. Other types of cameras are also possible. The camera may include a two-dimensional sensor or may have a three-dimensional spatial range. The camera may be, for example, a range detector configured to generate a two-dimensional image indicative of distances from the camera to a plurality of points in the environment. Other range detection techniques or devices may be used in conjunction with the camera. In an exemplary embodiment, the camera may be configured to use structured light technology, wherein the vehicle shows objects in the environment in a predetermined light pattern, e.g. a grid or checkerboard pattern, and detects reflections of the predetermined light pattern off the objects using the camera. Based on distortions in the reflected light pattern, the vehicle may be configured to determine a distance to a point on the object. The camera may be arranged behind a front windshield of the vehicle. However, in other embodiments, the camera may be mounted elsewhere in the vehicle, either inside or outside the vehicle.

The classification process of road condition information may also involve the controller determining a probability distribution (e.g., a gaussian distribution) of possible conditions associated with the detected road condition information. Such probability distributions may take the form of discrete probability distributions, continuous probability distributions, and/or mixed continuous discrete distributions. Other types of probability distributions are also possible.

Optionally, the system further comprises a wheel speed sensor and the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the component further based on the detected wheel speed.

Other measurement or sensing systems such as wheel speed sensors, accelerometers, CVT internal speed sensors, tire pressure sensors may be used in conjunction with the detector according to the present invention to obtain a more accurate analysis of local road conditions.

Optionally, the system further comprises a tyre pressure sensor and the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the component further based on the detected tyre pressure.

Optionally, the system further comprises a manual leveling sensor, and the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the component further based on the detected leveling.

Optionally, the system further comprises a steering angle sensor and the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the component further based on the detected steering angle.

The invention also relates to a vehicle comprising a CVT according to the invention.

Optionally, the vehicle may further comprise a detector according to the invention.

The invention also relates to a network server arranged for transmitting information representative of road conditions to a vehicle comprising a continuously variable transmission system according to the invention.

Optionally, the network server is arranged to receive information representative of road conditions from one or more sensors. These sensors may be installed in a vehicle comprising a CVT according to the invention. The sensor may also be placed elsewhere. Optionally, the network server is arranged for receiving information indicative of the clamping force or pressure from a vehicle comprising a CVT according to the invention.

Optionally, the network server is arranged for receiving an indication of the position of the vehicle from the vehicle and for communicating information to the vehicle representative of the vehicle position and/or nearby road conditions.

Optionally, the network server is associated with a memory storing information representative of road conditions. The memory may be a database. The content of the memory may be dynamic in that it may be updated periodically or continuously with information representative of road conditions obtained from sensors, for example sensors mounted to a vehicle comprising a CVT according to the invention, or sensors located elsewhere.

The present invention also relates to a method for operating a CVT system of a vehicle including a transmission having a first friction element and a second friction element coupled by a torque transmitting member. The method includes setting an optimal clamping force or pressure of at least one friction element on the torque transmitting member; acquiring upcoming road condition information; and adjusting a clamping force or pressure to at least one friction element on the torque transmitting member based on the obtained road condition information.

It is known that the electronic control unit of a vehicle can learn driving habits over a certain number of driving cycles, wherein some driving parameters (e.g. fuel-air mixture) and aspects of the vehicle operation are adjusted accordingly. The adaptive transmission control may be, for example, to adapt the shift characteristics according to the wishes of the driver and the driving situation. Such an adaptive system can be used in combination with the present invention to adapt not only to driving habits but also to the conditions of the road ahead, by which it is possible to provide a more comfortable experience for the vehicle occupants, and then to improve energy efficiency.

The vehicle may include sensors, such as Global Positioning System (GPS) devices, inertial measurement units, radio detection and ranging (e.g., radar) devices, laser rangefinders and/or light detection and ranging (e.g., lidar) devices, cameras, and/or actuators configured to modify the position and/or orientation of the sensors. The sensor system may also include additional sensors including, for example, sensors for viewing the vehicle interior systems, such as gas monitors, fuel gauges, engine oil temperature, etc. Other sensors are also possible. A CVT system according to the present invention may use one or more sensors of a sensor system of a vehicle to enable a controller of the CVT system to obtain upcoming road condition information. The sensor data may also be shared, for example, wirelessly with other entities.

The controller of the CVT system may be arranged to retrieve road condition information from different sources, such as by, for example, a detector mounted on the vehicle (e.g., sensor, camera, radar, laser, lidar, etc.), by the cloud (e.g., wireless communication with a network), by other vehicles in wireless communication with the vehicle, and/or by a sensor system used by a drive control system in an auto-assist, auto-drive vehicle, or auto-drive vehicle. Thus, the sensor for an autonomous vehicle may replace the detector according to the invention partially or completely. The controller of the CVT system can obtain information prior to the impact event so that the clamping force or pressure can be increased in time and against undesirably high impacts in the transmission.

Sensors for obtaining road condition information can be expensive, especially if accurate sensors for obtaining high quality measurements are arranged. However, the scanning unit may be used to map roads or areas. The retrieved road condition information may be stored in a database. The scanning unit may be a dedicated mapping system. This data may be taken by a vehicle comprising a CVT system according to the invention. The controller may be arranged to use the retrieved data as a primary source for the retrieved road condition information or to use the data to improve the prediction of upcoming road information. Moreover, it is possible to combine road condition data/measurements from multiple vehicles to improve the road condition information in the database, so that the data can be continuously improved and kept up to date. The road condition information may then be provided as a service to each vehicle and retrieved by the vehicle's controller. In addition, the controller may use a road classification system. For example, roads may be classified into different categories. With such a road classification system, the size of the data transmitted to the controller can be significantly reduced. In one embodiment, the detector is only used when certain conditions are met. For example, it may be that some roads are known from previous analysis or from the network so that the scanning of roads by the detector may be shut down. The controller of the CVT system can determine when to use the detector for scanning road conditions. For this purpose, the certainty and/or quality parameters may be specified by the controller of the CVT system to obtain the road condition information.

The controller of the CVT system may be arranged to obtain data from one or more sources, wherein a source may be based on a service comprising a subscription system, while other sources may provide open access. In one embodiment, the controller will first check for available sources for providing upcoming road information, after which the controller may select multiple sources if available and evaluate the road condition by considering the selected sources. In another embodiment, a plurality of vehicles may be arranged to communicate with each other to exchange information about road conditions or the like. Sensed data from an autonomous vehicle and/or an autonomous vehicle that does not include a CVT control system according to the invention may be used, at least in part, by a vehicle that includes a CVT control system.

Furthermore, a CVT system according to the present invention may include a non-transitory computer-readable medium having stored thereon program instructions executable by at least one processor to provide the functionality described by the methods herein.

In the present disclosure, the transmission in the illustrated embodiment includes two friction elements and a torque transmitting member, however, other combinations of friction elements and torque transmitting members are also possible.

It should be appreciated that any of the aspects, features and options described with respect to CVT systems are equally applicable to the vehicle and the described method. It will also be apparent that any one or more of the above aspects, features and options may be combined.

Drawings

The invention will be further elucidated on the basis of exemplary embodiments shown in the drawings. The exemplary embodiments are given by way of non-limiting illustration. It should be noted that the figures are only schematic representations of embodiments of the invention given by way of non-limiting example.

In the drawings:

FIG. 1 shows a schematic diagram of an embodiment of a CVT system;

FIG. 2 shows a schematic diagram of a control strategy of the CVT system;

FIG. 3 shows a schematic top view of a vehicle and its surrounding area;

FIG. 4a shows a schematic side view of a vehicle and its surrounding area;

FIG. 4b shows a schematic top view of a vehicle and its surrounding area;

FIG. 5a shows a schematic top view of a vehicle and its surrounding area;

FIG. 5b shows a schematic top view of a vehicle and its surrounding area;

FIG. 6 shows a schematic side view of a vehicle;

fig. 7 shows a schematic diagram of the control strategy of CVT system 1;

FIG. 8 shows a flow chart of an embodiment of a method; and

Fig. 9 shows a schematic diagram of an example of a control strategy of the CVT system 1.

Detailed Description

Fig. 1 is a schematic diagram of an example of a system 1 of a Continuously Variable Transmission (CVT) according to an exemplary embodiment of the present invention. CVT system 1 provides for the controlled application of engine power from a motor 11, such as an engine. In this example, the motor 11 is coupled to an input shaft 18a of the CVT via a clutch 11 a. The CVT converts rotational speed and torque from the motor 11 to (different) rotational speed and/or torque at the output shaft 18a of the CVT. The CVT includes a transmission 2 for providing mechanical power transfer, wherein input from a prime mover 18a is used to deliver variable output speed and torque to the wheels 13 of the vehicle. The input from the input shaft may maintain a constant angular velocity. The transmission 2 includes a primary cylinder 3 and a secondary cylinder 4. Furthermore, the transmission 2 comprises two friction elements 15, 16, namely a first friction element 15 and a second friction element 16, wherein the first friction element 15 is connected to the second friction element 16 by means of a torque transmitting member 17, such as a thrust belt 17. Other torque transmitting members 17 are also possible, such as V-belts, chains or flexible members. In this example, the first friction member 15 is implemented as a first conical pulley. In this example, the second friction member 16 is implemented as a second conical pulley. The first conical pulley 15 is connected to the input shaft 18a. The second cone pulley 16 is connected to the output shaft 18b. The primary cone pulley 15 comprises two sheaves 19a, 19b, in this example a fixed sheave 19a being axially fixed relative to the input shaft 18a, while a movable sheave 19b is axially movable relative to the input shaft 18a. The second cone pulley 16 comprises two sheaves 19c, 19d, in this example a fixed sheave 19c axially fixed relative to the output shaft 18b and a movable sheave 19d axially movable relative to the output shaft 18b. The torque transmitting member 17 is shown in this embodiment as a thrust belt 17, which may be, for example, a segmented steel V-belt, a chain, a flexible member, or the like, the torque transmitting member 17 being sandwiched between two pairs of tapered sheaves 19a, 19b and 19c, 19d of the pulleys 15, 16. By axial movement of the movable pulleys 19b, 19d of the first pulley 15 and/or the second pulley 16 of the transmission 2, the clearance between the sheaves, and thus the running radius of the thrust belt 17, can be adjusted. In this example, the transmission 2 may continuously change its gear ratio. The CVT system 1 is actuated using hydraulic power from the hydraulic actuation system 6. The hydraulic actuation system 6 has a first hydraulic line 7 and a second hydraulic line 8, the first hydraulic line 7 being connected to a first friction element 15 and the second hydraulic line 8 being connected to a second friction element 16. The clamping force or pressure of the first friction element 15 and/or the second friction element on the torque transmitting member 17 may be regulated and controlled by using an electronic engine control unit 14 (ECU) or a separate transmission control unit 5 (TCU, also referred to as a transmission control module TCM). In this embodiment, the TCU5 is connected with a hydraulic actuation system 6. A Digital Image Processing Control Unit (DIPCU) may be provided that operates as a central control unit, processing all types of data from the sensors, including the upcoming road condition information that is retrieved. The output of the DIPCU may be used by TCU 5. However, the DIPCU may also be part of the TCU 5. The DIPCU may be arranged to allow processing of data.

The TCU 5 may be arranged to control an actuator, e.g. a movable sheave, of the CVT system 1.

The hydraulic system 6 may comprise hydraulic components arranged for converting actuator signals from the TCU 5 into hydraulic pressure. The pressure may include a first pressure and a second pressure. The first and second pressures are converted into clamping forces on the first and second pulleys 15, 16 via the first and second hydraulic lines 7, 8, respectively.

The TCU or controller 5 may receive input from the cloud (such as road conditions, weather conditions, objects, GPS locations, traffic information, etc.) from sensors and/or from the DIPCU. Based on the predicted road conditions, the controller 5 may set an appropriate clamping force or pressure of the friction element 15 and/or the friction element 16. The controller 5 may reconstruct the road environment and send more accurate updates to the cloud.

The upcoming road information may be received by the controller 5 through a wired connection or a wireless connection. In the case of wireless data communication, the wireless connection means may be arranged to transmit signals via a mobile data transmission protocol, e.g. 3G, 4G, 5G etc. However, other wireless protocols such as WiFi (e.g., wireless communications conforming to the IEEE802.11 standard or other transmission protocols) may also be employed to obtain wireless communications. Combinations of wireless protocols are possible.

The CVT system 1 according to the invention may also be used in an autonomous vehicle and/or in a self-driving vehicle. Various computing systems and sensor systems are used in autonomous vehicles for transportation from one location to another. The driving control system of the autonomous vehicle may be arranged to receive a plurality of data points corresponding to the surroundings of the autonomous vehicle by means of one or more cameras and/or sensors. For example, lidar sensors may be employed to obtain a three-dimensional (3D) point cloud. Lidar systems may use a reflected beam from the beam to detect and measure the distance between the vehicle and the object. Lidar works independently of ambient light so that a 3D map of the surroundings can be taken even in conditions of insufficient light (e.g. at night). Although accurate, lidar systems are generally more expensive than systems including, for example, one or more cameras and/or radars.

The driving control system may be further arranged to collect information indicative of road conditions in the vicinity of the vehicle. For example, a 3D point cloud of scanned areas through lidar sensors of the vehicle surroundings may be used by the controller of CVT system 1 to retrieve upcoming road condition information for the vehicle. The acquired upcoming road condition information may be used by the controller 5 to adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17.

The controller 5 of the CVT system 1 may be arranged to use data from sensors already available and provided for the autonomous vehicle and/or the driving control system of the autonomous vehicle to retrieve information about the upcoming road condition. Thus, CVT system 1 may not require the placement of additional sensors and/or detectors, thereby significantly reducing costs.

The control of the clamping force may be in addition to the normal calculation and/or control of the clamping force and pressure in the transmission 2. If the clamping force or pressure required for normal control is sufficiently high, the controller may decide not to change the clamping force or pressure in the transmission 2. If it is too low, the controller 5 may decide to change the clamping force or pressure required.

Other components coupled to CVT system 1 or included in CVT system 1 may include an oil pump 12, other sensors (e.g., one or more speed sensors 9, lever position sensor 9a, ABS speed sensor 9b, turbine speed sensor 9c, pressure sensor 10, etc.), a forward-neutral-reverse (DNR) set 9d, etc. The components of CVT system 1 may be arranged to operate in an interconnected manner with each other and/or with other components coupled to the respective system. In other examples, CVT system 1 may include more, fewer, or different systems, and each system may include more, fewer, or different components. In addition, the systems and components shown may be combined or separated in any number of ways.

Fig. 2 shows a schematic diagram of the control strategy of CVT system 1. Certain environmental conditions 20 for a vehicle including CVT system 1 may be associated with operation and control of CVT system 1. For example, the surface of the road or ground on which the vehicle is traveling or is to be traveling may be related to the control of the CVT system 1. Therefore, the control strategy of the CVT system 1 will acquire the information 21 representing the road condition. The information indicative of the road condition may relate to road conditions, such as mountain information, weather conditions, snow, rain, a slope of the ground or road, objects on the road, curbs, road irregularities, road surfaces, road flatness, traffic (e.g., traffic Message Channel (TMC) data, etc.), and the like. It should be appreciated that the information representative of the road condition may include a numerical value for the road condition. The information representing the road condition may also be encrypted or encoded. The information representing the road condition may also include a classification of the road condition. The road condition information herein refers to information representing a road condition unless otherwise specified.

This information is then sent to the controller or TCU 5 of CVT system 1. According to the example of fig. 2, the controller comprises two units, namely a clamping force calculation unit arranged to determine and/or calculate a clamping force and a pressure setting unit arranged to set a pressure command. The controller 5 is arranged to predict a torque peak in the CVT based on the received information indicative of the road condition and to adjust the pressure setting to be sent to the hydraulic system 6. The hydraulic system 6 is arranged to control the friction elements 15, 16 based on a pressure setting signal from the controller 5. In this way, the hydraulic system 6 will adjust the hydraulic pressure or clamping force of the at least one friction element 15, 16 on the torque transmitting member 17 in accordance with the predicted torque. In this example, control of the first friction element 15 may be directed to the clamping torque of a main portion of the transmission, while control of the second friction element 16 may be directed to the clamping torque of a secondary portion of the transmission. The controller 5 may be arranged to determine a desired set point for the hydraulic or clamping force for the first friction element 15 and the second friction element 16, respectively.

Based on the vehicle speed and the identified position of the object, the time of impact of the road condition on all wheels can be calculated. This may be performed for the front wheels of the vehicle or for the rear wheels of the vehicle. Even when the wheels are not directly connected to the transmission shaft of the CVT, the bumps can cause the vehicle to be unbalanced, which may also be noticeable at other wheels and transmission shafts of the CVT. A decision about the path may be performed for all wheels, which may be based on the vehicle speed and the steering wheel angle signal. When an object or a road unevenness is on the path of the wheel, the influence time can be calculated. The left and right wheels may have their own predicted paths. The detected objects can be summarized to the behaviour of the two wheels. However, the influence on each wheel may also be considered and calculated separately.

Based on characteristics of the road (e.g., objects), the severity of the impact may be calculated. For example, an ongoing curb may be worse than an upcoming curb, larger or deeper indentations may have a greater impact, etc. The same object, impacting a non-driving wheel (e.g., a rear wheel) may have less impact than impacting a driven wheel (e.g., a front wheel). The difference between the left and right wheels may result in different types of effects. The vehicle speed may play an important role in the prediction of the influence of the controller 5. The same bumps in the road will have a higher impact severity at higher vehicle speeds.

Fig. 3 shows a schematic top view of a vehicle 24 and its surrounding area 25. In this example, the vehicle 24 includes a CVT system 1. In the surrounding area 25, different irregularities in road conditions and objects 26, 27, 28 have been detected and identified by the CVT system 1. The vehicle 24 includes four wheels, namely two front wheels 29, 30 and two rear wheels 31, 32. In this example, the vehicle turns left, causing the front wheels 29, 30 to turn. The controller 5 may predict the paths 33, 34, 35 and 36 of the respective wheels 29, 30, 31 and 32 accordingly. The uneven portions and the objects 26, 27, 28, such as their position, position relative to the wheels, size, shape, etc. constitute part of the road condition information. The controller 5 may then predict an effect on the torque in the CVT, e.g. the torque of the input shaft 18a and/or the output shaft 18b of the CVT, here the effect of the presence of the uneven portions and objects 26, 27, 28, based on the retrieved road condition information. Based on the predicted effect, the controller 5 then adjusts the clamping force or pressure of at least one friction element on a torque transmitting member in the transmission 2 of the CVT system 1 as necessary. In this example, the paths 33, 34, and 36 of the respective wheels 29, 30, and 32 are predicted by the controller 5 so as not to encounter irregularities 26, 27 or objects 28 on the road in the surrounding area 25 of the vehicle 24. However, the controller 5 may predict torque (peak) and control pressure or clamping force in at least one of the friction elements 15, 16 of the transmission 2 based on the predicted encounter where the path 35 of the wheel 31 is predicted to encounter the object 28.

The local vehicle environment may be determined in the form of a surrounding area 25. In one embodiment, the monitoring range may be about 7.5 meters in front of the vehicle and about 2 meters behind the vehicle. Other ranges may be used and/or the ranges may be adjusted by using actuators that may be manually and/or automatically controlled by the controller 5.

In an example, the controller 5 may be arranged to build a two-dimensional map of roads in front of, below and behind the vehicle 24. When a new screen such as a camera image is available for analysis, the screen may be added in front of the existing map, and the screen at the end of the existing map corresponding to the rear of the vehicle may be deleted. However, the frame may also be stored in memory and/or a database. This process or generates a complete map of the surroundings of the vehicle 24, which map is related to the positions of all wheels 29, 30, 31, 32 of the vehicle 24. In the map, features or related characteristics of the detected road condition may be indicated, such as, but not limited to, paving, asphalt, rain, snow, etc., or any kind of object.

Fig. 4a shows a schematic side view of a vehicle 24 comprising the CVT system 1 and its surrounding area. The vehicle 24 according to this example comprises a detector 38, wherein the controller 5 of the CVT system 1 is arranged for retrieving road condition information from the detector 38. In this example, the detector 38 is arranged for determining a road condition in front of the vehicle 24. The detector 38 is also positioned at the front of the vehicle 24 to form a front scanning area 39 on the ground or road 37. Road condition information in the front scanning area 39 is recorded and analyzed by the detector 38. In this example, the controller 5 may be arranged for wireless communication connection to the detector 38.

The controller 5 receives upcoming road condition information from the detector 38 and adjusts the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 based on the received road condition information. The controller 5 is arranged to predict a change in the input and/or output torque of the transmission 2 based on the retrieved road condition information and to adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 according to the predicted torque change.

The controller 5 may be arranged for predicting the moment at which the torque input and/or output by the transmission 2 will change based on the road condition information retrieved by the detector 38. For this purpose, the distance between the front scanning area 39, the contact point of each wheel 29, 30, 31, 32 with the ground 37 may be important. The speed of the vehicle 24 in the travel direction 40 and the predicted and/or estimated wheel paths 33, 34, 35, 36 for each wheel of the vehicle 24 may be important. The adjustment of the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 in accordance with the predicted torque variation may be performed by the controller 5 of the CVT system 1 before or simultaneously with the predicted moment.

In this example, the detector 38 comprises an optical camera 38 arranged for producing an image. The camera 38 may be arranged to perform image processing. For this purpose, the camera 38 may include hardware, such as an application specific integrated circuit ASIC, in order to perform image processing of the captured image. A digital processing control unit (DIPCU) may be arranged to allow data processing. The DIPCU may be a central control unit arranged to process all types of imaging devices, including image processing dedicated to embodiments according to the invention. The TCU 22 may use the output of the image processing. Note that the divcu may be part of the TCU. The TCU input unit 22 may be arranged to receive input signals from measured values of road conditions of the camera 38. Furthermore, the TCU output device 23 may be arranged to generate and/or issue a control signal or output signal based on the input measurement, wherein the control signal or output signal takes into account the prediction of the torque peak. The pressure of the two friction members 15, 16 of the transmission 2, e.g. the pulley clamping force, can then be controlled by the hydraulic system 6 based on the predicted torque peaks.

The camera 38 is arranged for capturing an image of a portion of the road 37 in front of the vehicle 24 in the path of the direction of travel 40 of the vehicle 24 and in front of the vehicle 24, the camera 38 may comprise a lens system arranged to capture one or more images by the camera 38. In addition, the image is converted into an electronic signal by a digital image sensor. According to some embodiments, the image processing step may include basic techniques such as white balance correction, sharpening, and/or contrast enhancement. Alternatively or additionally, digital image processing may be performed by software. The digital processing control unit (DIPCU) may be arranged to pass the original captured image from camera 38 to a specified record with all types of road characteristics that have been classified, and to make the result available to TCU 5.

Algorithms involving image processing may result in the need for specific computation times to compute road condition information based on one or more pictures. To reduce the calculation time, the size or resolution of the screen may be selected based on the actual vehicle speed. In an advantageous embodiment, a higher vehicle speed may result in a larger screen or a lower resolution screen. Based on one image, a portion of the road may be reconstructed. The process may be repeated on the fly to establish the road environment on a frame-by-frame basis. The road condition information may also be determined from a plurality of pictures. The inter-picture differences may then be used to determine road condition information. Furthermore, an object recognition algorithm may be applied. In some embodiments, the detector 38 may be a stereoscopic optical camera with near infrared view.

In another example, the object recognition algorithm may employ object recognition to identify curbs, potholes, and other types of objects. In the case of curbs or indentations, the height, width, and/or location may be identified. In addition, for a curb, it may also be determined whether the curb is traveling or is about to leave. Further, the relevant characteristic identifying the road condition may be an international flatness index (IRI) classification and/or a road surface classification.

In fig. 4a different distances L1-L4 are shown, where L1 is the horizontal distance between the position of the detector 38 and the contact point of the front wheels 29, 30 with the ground or road 37. L2 is the horizontal distance between the contact point of the front wheels 29, 30 with the ground 37 and the front side of the vehicle 24. L3 is the horizontal distance between the front side of the vehicle 24 and the first field of view edge 42. L4 is the distance between the first field of view edge 42 and the second field of view edge 43. In one example, L1 may be about 1 meter; l2 is about 1 meter; l3 is about 4 meters; and L4 is about 4 meters. Other configurations are also possible.

The sensors of the detector of the CVT system 1 may be manually and/or automatically adjusted by the controller 5 or other control system, such as a drive-assisted autonomous vehicle and/or a drive control system in a self-driving vehicle. For example, when the detector includes a camera, the detector may also include additional actuators to adjust the field of view of the camera. The adjustment may be automatically adjusted based on the vehicle speed around the vehicle and/or environmental conditions such as fog, rainfall, snowfall, etc. The controller 5 may be arranged to detect whether the field of view of the detector 38 (or the camera in this embodiment) is blocked, such as by another vehicle in the vicinity, blocking at least part of the field of view. In the event that the detector 38 is unable to obtain road condition information, the controller 5 may return the CVT to a safe operating mode, wherein a safety margin of clamping force or pressure in the transmission is employed in order to reduce the risk of encountering undetected road conditions and prevent the belt slip. If the controller 5 detects other vehicles in the vicinity of the vehicle 24, it may provide the controller 5 with road condition information related to the path of the vehicle 24 on the road 37, the vehicle 24 may also take this information into account.

The controller 5 may be configured to determine an intended adjustment of the pressure or clamping force based on one or more of the location of the changing road condition, the direction of travel of the vehicle 24, the retrieved road condition, and the relative movement between the vehicles. The predicted pressure or clamping force may be determined based on analysis, simulation, and/or comparison of the retrieved road condition data along with one or more predetermined road condition data sets. The one or more predetermined road condition data sets may include a training data point set established from data from other vehicles detecting road conditions in various scenarios.

For example, each particular road condition data set may be classified and labeled by the controller 5 based on various features and characteristics, such as features that identify road flatness (e.g., road conditions that vary while traveling on a road, road irregularities, potholes, obstacles, etc.), and driving activity of the vehicle 24. The retrieved road conditions and the road conditions encountered by the predictions of the wheels of the vehicle 24 may be performed using a cluster analysis in which datasets from the retrieved road condition data are grouped in such a way that features or objects in the same group or cluster are somewhat more similar to each other than to features or objects in other groups or clusters. Other types of analysis may also be used and may include one or more supervised and unsupervised learning-based algorithms. Analysis of the retrieved road condition information may be used to calculate and/or determine a probability distribution of road conditions to be encountered by the vehicle 24. From this analysis, abnormal and/or changing road conditions that may be associated with the CVT system 1 may be identified. The controller 5 may also calculate an estimated or expected time for each wheel to potentially come into contact with the upcoming road conditions of the vehicle 24. The necessary adjustment of the clamping force expectations in the CVT system 1 can be performed in advance or on time if necessary. In this way, the controller 5 can avoid adverse effects due to too low a clamping force or pressure in the transmission, or avoid lower efficiency of the CVT system 1 due to too high a clamping force in the transmission of the CVT. In some embodiments, the preferred direction of travel of the vehicle 24 may also be determined based on analysis of the retrieved road condition information by the controller 5. For example, a route for the vehicle may be presented to the driver of the vehicle 24, or a route that may be followed, for example, in the case of an autonomous vehicle. It may be preferable to travel on a lane where CVT efficiency may be increased. For example, based on the retrieved road conditions, the lane may be associated with an expected reduction in the necessary clamping force and thus increase the efficiency of the CVT system 1 of the vehicle 24 traveling on the lane.

In some embodiments, the controller 5 may determine characteristics from the acquired upcoming road condition data and provide a correlation score for each characteristic that is associated with the impact on the required clamping force in the CVT system 1 to avoid slip in the torque transfer member 17 while providing advantageous efficiency. Such a relevance score may also be associated with a likelihood that wheels of the vehicle 24 encounter road features and/or the severity of such encounters.

The effect of certain road conditions (e.g., potholes) on the transmission 2 of the CVT system 1 may also depend on the speed of the driving vehicle 24. Therefore, the controller 5 can determine the effect not only from the running speed of the vehicle but also propose to change the vehicle speed so as to reduce the influence of the acquired road condition on the CVT system 1. The controller may be configured to provide instructions and/or advice to adjust the speed of the vehicle 24 and/or the direction of travel of the vehicle 24 based on the necessary clamping force or pressure expected in the CVT system 1. Further, the data may be provided wirelessly to the cloud so that the data may be shared with other users or vehicles. It is also possible to directly provide road condition information to other vehicles 24 traveling in the vicinity of the vehicle 24 by using wireless communication. Accordingly, the controller 5 may not be limited to adjusting the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 of the transmission 2 of the CVT system 1 based on the retrieved road condition information. In some embodiments, the controller 5 may suggest or instruct adjustment of other parameters, however, the adjustment may also be performed by another control system in communication with the controller 5 of the CVT.

Fig. 4b shows a schematic top view of the vehicle 24 and its surrounding area 25. The vehicle having the CVT system 1 includes a detector that defines a field of view 41 in front of the vehicle. The optical camera 38 of the detector may be placed at a sufficient height to provide a sufficiently far field of view with a correct depth field of view. The front scanning area 39 is defined by a distance L4 and field angles α and β. Actuators may be provided to adjust the angles alpha, beta. In this example, the uneven portion 27 in the road condition (e.g., a pothole) is detected in the front scanning area 39 of the vehicle 24. Since the vehicle 24 is traveling in the traveling direction 40 or is intended to travel forward, the path of the wheels 29, 30, 31, 32 can be determined. As can be seen from fig. 4b, the coincident paths 33, 35 of the front wheel 29 and the rear wheel 31 of the vehicle will encounter a road irregularity 27 in the form of a depression. The controller 5 acquires road condition information and predicts the effect of the indentations 27 on the CVT system 1 of the vehicle 24. If necessary (e.g., if the controller predicts that there is a risk of slipping the torque transmitting member 17), the controller 5 of the CVT system 1 adjusts the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17. Preferably, the risk of each wheel 29, 30, 31 and 32 of the vehicle 24 is assessed based on the predictions. However, a simplified embodiment may be employed in which only detection of road conditions in the scanned area is considered, regardless of the wheel path. Alternatively or additionally, the controller 5 of the CVT system 1 may be arranged to act with probabilities for the wheel paths 33, 35 and 34, 36.

Fig. 5a and 5b show a schematic top view of the vehicle 24 and its surrounding area. The vehicle 24 includes a detector 38 that provides a front scan area 39, the front scan area 39 being formed by the projected field of view of the detector 38. In an example, the detector 38 may be an optical camera. As the vehicle travels in the travel direction 40, it may encounter an area 44 where road flatness varies significantly, for example, due to snow on a road, another road, objects on a road, and so forth. The path 33, 34 of the front wheels 29, 30 of the vehicle 24 may be determined. If it is deemed necessary to adjust the clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17, the controller may predict the moment at which the front wheel will encounter the region 44. It will be appreciated that in view of road conditions formed by water (rain), snow, gravel or similar dispersed irregularities, a simplified embodiment that only considers detecting road conditions in a scanned area and not considering the wheel paths therein would be very effective.

The controller 5 may determine the general road condition by using the information from the detector 38 and the classification of the road type, IRI classification and/or road surface classification. Classification may already be performed by the DIPCU. In one embodiment, the controller 5 may monitor a range of approximately 20 meters in front of and behind the vehicle. Advantageously, the controller 5 is arranged not to change "quickly" from a clamping force or pressure configuration in the transmission for severe road conditions to less severe road conditions. For example, if one picture (a road of about 4 meters) indicates that the road condition is significantly improved, this must be confirmed for several consecutive frames or a certain travel distance before the clamping force or pressure build in the previous transmission can be set to a new level. Image filtering may be applied to images obtained by a camera. In an exemplary embodiment, the surface roughness may be classified into different categories, such as flat, asphalt, concrete, light-load road, heavy-load road, off-road, and the like. Each level may require a different adjustment of the clamping force or pressure in the transmission of the CVT system.

Fig. 5b shows the vehicle 24 initially moving in the direction of travel 40 and steering to the right. In this example, a front wheel path 33 is shown. The controller 5 may be arranged to determine such a path and verify whether the predicted path will encounter a road condition that may require adjustment of the clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17. In this case, the relevant road unevenness is detected. Although the predicted path 33 does not meet the road irregularities 27, the controller may take into account possible variations in the path, represented by the first boundary path 45 and the second boundary path 46. Thus, the system may take into account the relevant road conditions around the path 33 detected in the region between the first and second boundary paths 45, 46 to reduce risk and/or prevent slipping of the thrust belt in the transmission 2. Alternatively or additionally, the area surrounding the road irregularities may be inflated by the controller to reduce risk and/or prevent slipping of the thrust belt in the transmission 2. It should be appreciated that the field of view of the detector 38 may be associated with the steering direction of the wheels so as to at least generally look into the path direction of the vehicle.

Fig. 6 shows a schematic side view of a vehicle 24, the vehicle 24 comprising the CVT system 1 encountering an exemplary driving situation. Other implementations are also possible. In the first case (a), the vehicle includes a detector 38 that acquires road condition information in a front scanning area 39 of the vehicle 24. The road condition information is analyzed and sent to the controller 5. In this case, a road unevenness 27 is detected, which is expected by the controller 5, to adjust the clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17 in the transmission 2 of the CVT system 1. Therefore, the controller 5 will adjust the clamping force based on the road irregularities 27. Furthermore, after passing the adverse road condition, if the controller 5 has determined that the scanned upcoming road condition information provided by the detector 38 allows such a configuration, the controller may readjust the clamping force based on the new measurement value in the forward scan 39.

In the second case (b) in fig. 6, two vehicles 24, 47 are shown, both comprising the CVT system 1 with the detector 38. Both vehicles travel behind each other in the travel direction 40. There is sufficient distance between the two vehicles 24, 47 that the detector 38 of the first vehicle 24 will be able to successfully scan the front scanning area 39. The second vehicle 47 detects the relevant road irregularities 27 in its front scanning area 39. Accordingly, the controller 5 of the second vehicle 47 may adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 based on the acquired upcoming road condition information. If the traveling direction 40 is maintained, the first vehicle 24 will also encounter the road irregularities 27. The front scanning area 39 of the detector 28 of the first vehicle 24 has not reached the road irregularities. However, the second vehicle 47 may have wirelessly transmitted the upcoming road condition information assessed by the detector 38 of said vehicle 47 to the CVT system 1 of the first vehicle 24 before the detector 38 of the first vehicle 24 detects the uneven portion 27. The wireless communication of the road conditions may be done directly, for example by establishing a direct communication between the two vehicles 24, 47, or indirectly, for example by using the internet or a cloud protocol. It should be appreciated that the second vehicle may also transmit clamping force or pressure information to the first vehicle. Then, the clamping force or pressure information indicates the road irregularities 27.

The third case (c) in fig. 6 corresponds to the second case (b). Likewise, two vehicles 24, 47 travel behind each other, both comprising the CVT system 1 and a further detector 38 for detecting the road condition in the front scanning area 39 of the vehicles 24, 47. In this case, however, the distance between the two vehicles is limited such that the viewpoint of the detector 38 of the first vehicle 24 is blocked by the second vehicle 47. As a result, the detector of the first vehicle 24 is unable to obtain the front scanning area 39 of the ground 37 in front of the vehicle, and thus the upcoming road information of said vehicle 24. In such a case, the controller 5 of the vehicle 24 may not be able to evaluate the upcoming road condition such that if no other source can provide upcoming road information, the controller 5 of the vehicle 24 may pre-adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 of the transmission 2 in the CVT system 1

Alternatively or additionally, the controller 5 of the first vehicle 24 may receive road information from the vehicle 47, which vehicle 47 has scanned the road before the vehicle 24 without any limitation, and thus the controller 5 of the vehicle 24 may adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 of the transmission 2 in the CVT system 1 based on the received road information. Alternatively or additionally, in the case of an autonomous, self-driving or assisted driving vehicle, the controller 5 of the first vehicle 24 may instruct the control system of the vehicle to increase the distance to the second vehicle 47, or in the case of a driver operated vehicle suggest that the driver increases the distance and/or inform the driver that the point of view of the vehicle is blocked by the second vehicle 47. Also in this case, the second vehicle 47 may transmit road condition information to the first vehicle 24, if possible, as in the second case (b).

In a fourth case (d) in fig. 6, a first vehicle comprising the CVT system 1 is travelling behind a second vehicle 47, wherein the second vehicle 47 comprises an automatic self-driving vehicle with one or more sensors 48, the sensors 48 being arranged to scan and evaluate the surrounding area of the vehicle 47. The one or more sensors 48 of the second vehicle 47 may provide a 360 view of the surrounding area that may be used by the first vehicle 24 to obtain road condition information. Although the detector 38 of the first vehicle 24 has not yet reached the road irregularities 27 in this case, the controller 5 of the first vehicle 24 may have received relevant upcoming road condition information from the first vehicle 48. This shows the mutual compatibility between different vehicles 24, 47 comprising different sensor systems 38, 48, respectively. Note that the second vehicle 47 may not include the CVT system 1. Communication between vehicles may be accomplished directly or indirectly, such as by utilizing a cloud

In a fifth case (e) in fig. 6, a vehicle 24 comprising a CVT system 1 is shown, wherein the controller 5 is arranged for retrieving information indicative of an upcoming road condition. The controller 5 (not shown) is arranged for adjusting the clamping force or pressure of at least one friction element 15, 16 on a torque transmitting member 17 of the transmission 2 in the CVT system 1 according to the retrieved road condition information. In this example, information about the road irregularities 27 of the vehicle 24 may be obtained using local memory, cloud information, and/or road condition information retrieved from other vehicles and/or arrangements. For example, a GPS sensor may be used to determine the position and speed of the vehicle 24, by which the controller may adjust the clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17 when deemed necessary if upcoming road condition information is provided. For example, in this example, the detailed upcoming road condition information may be available in the memory of the vehicle 24, or may be downloaded from a server, and the controller 5 may retrieve the upcoming road condition information. Further, the controller 5 may correlate the upcoming road condition information with the position and speed of the vehicle to predict whether one or more wheels will encounter the road irregularities 27.

Fig. 7 shows a schematic diagram of the control strategy of CVT system 1. Certain environmental conditions 20 for a vehicle including CVT system 1 may be useful for operation and control of CVT system 1. For example, the surface of a road or ground on which the vehicle is traveling or is to be traveling may be related to the control of the CVT system 1. Therefore, the control strategy of the CVT system 1 will attempt to acquire road condition information as prediction information by using, for example, an optical input device such as a camera as a detector, and/or information obtained by wireless communication with the cloud. Advantageously, the optical input device may be positioned at the front of the vehicle, providing at least a front scanning area for the vehicle. In addition, the reaction information may also be obtained from other sensors for enhancing road condition information, such as a wheel speed sensor, a tire pressure sensor, a manual horizon sensor, and/or a steering angle sensor. The road condition information acquired from the sensors and/or the cloud is then transmitted to the controller or TCU 5 of the CVT system 1.

According to the embodiment of fig. 7, the controller 5 comprises two units, namely a clamping force calculation unit 22 arranged to determine and/or calculate a clamping force and a pressure setting unit 23 arranged to generate a pressure setting command. The controller 5 receives road condition information and may predict a torque peak based on information representing the road condition. The hydraulic system 6 is arranged to control the friction members based on pressure setting commands from the controller 5. In this way, the hydraulic system 6 will adjust the hydraulic pressure and/or the clamping force of the at least one friction element 15, 16 on the torque transmitting member 17 in accordance with the predicted torque. In this example, control of the first friction element 15 may be directed to the clamping torque of a main portion of the transmission, while control of the second friction element 16 may be directed to the clamping torque of a secondary portion of the transmission. The hydraulic system 6 may also be arranged to control other components of the CVT system 1.

During the contact of the wheel with the road irregularities or objects on the road, all types of signals can be measured. For example, events may be measured by using severity estimation sensors such as internal speed sensors, tire pressure sensors, steering wheel angle sensors, manual horizon sensors, wheel speed sensors, accelerometers, and/or accelerator pedal demand sensors. Pattern recognition may be performed to identify roads or road bumps. Other features may be used such as the fact that the position of the feet of the vehicle driver may change very quickly due to vehicle movement. Based on this information, a more accurate determination of the road condition can be performed. The measurements may be used to improve the quality of information on available roads in the cloud by sending the information or a summary of the information to the cloud.

The required clamping force or pressure in the transmission 2 may be calculated based on corrected general road conditions, wherein the road condition signal may be linked to some required clamping force or pressure level. This can be calibrated for each type of vehicle 24 during design and development of the CVT system 1.

The severity of the impact, impact on the wheels, object classification, desired clamping force or pressure level, etc. may be based on calibration, testing, powertrain models, and/or training (e.g., artificial intelligence). The powertrain model may predict torque fluctuations at the driven shaft, and thus the required clamping force or pressure level.

In one embodiment, a rough road condition assessment is obtained by using a camera. The rough road conditions may be relevant characteristics, for example, at about 20 meters around the vehicle, which may include, for example, poor road surfaces, detected through the use of cameras, but not recorded by other sensors (such as internal speed sensors, tire pressure sensors, steering wheel speed angle sensors, accelerometers, and accelerator pedal demand sensors). In this case, the expected/predicted road condition information may not correspond exactly to the effect on the vehicle, so that the camera input may be corrected by measurement estimation by other sensors, depending on the reliability of the actual input.

Weather information may be useful for the clamping force or pressure required in the transmission 2 of the CVT system 1. Road type classification from the cloud may be remapped to the classification used in the present invention (e.g., IRI index, road surface, etc.). The available information of road objects like potholes, curbs etc. and their characteristics can be used by the controller 5 to predict the possible impact. The GPS location may be used to determine the exact location of the vehicle. The GPS location of the vehicle may also be used for calibration and updating the known location of the road irregularities in a storage device such as a cloud. Road condition information from previous vehicles may be obtained by vehicle 24. The required clamping force or pressure in the position dependent transmission 2 may be obtained based on a prior pass of the same vehicle or other vehicle capable of communicating this information with the vehicle 24 comprising the CVT system 1.

Fig. 8 shows a flow chart of a method according to the invention. The method may be used to operate a CVT system 1 for a vehicle 24, the CVT system 1 including a transmission 2 having a first friction element 15 and a second friction element 16 coupled through a torque transmitting member 17. The method comprises the step of setting a clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17. The clamping force or pressure may be optimally or advantageously selected in such a way that a reserve or safety margin, which may adversely affect the efficiency of the CVT system, may be avoided or reduced. The method may further comprise the steps of retrieving information indicative of an upcoming road condition, and adjusting the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17 based on the retrieved information. Methods for operating a continuously variable transmission system of a vehicle may be performed at least in part using dedicated hardware structures, such as using ASIC and/or FPGA components. Alternatively, the method may be performed at least in part using a computer program product comprising instructions for causing a processor of a computer system to perform the above-described steps of the method according to the invention. The processing steps may in principle be performed on a single processor, in particular the step of retrieving upcoming road condition information. It should be noted, however, that at least one step may be performed on a separate processor.

The controller 5 may be arranged to receive current traffic conditions in the vehicle environment, which may be information representing at least part of upcoming road conditions. Traffic condition information may be rough measurements such as light weight traffic, medium traffic, and heavy traffic. However, traffic condition information may also include more detailed or specific data such as the location and speed of other road users (e.g., automobiles, cyclists, pedestrians, etc.), the status of traffic lights, and/or other characteristics that may have an impact on traffic. The controller 5 may be arranged to adjust the clamping force or pressure of the at least one friction element 15, 16 on the torque transmitting member 17, possibly in combination with other retrieved road condition information, based on the retrieved traffic condition information. Traffic condition information may also be based at least in part on traffic predictions through a computer model. Further, the controller 5 may be arranged to wirelessly retrieve the traffic condition information from a network or cloud, an internal system in the vehicle and/or an external device (e.g. a smart phone).

The invention is described herein with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit of the invention. For purposes of clarity and conciseness, features are described herein as part of the same or different examples or embodiments, however, alternative embodiments having combinations of all or some of the features described in these different embodiments are also contemplated.

CVT system 1 may be implemented in the form of a vehicle 24 or may take the form of a vehicle 24. Alternatively, CVT system 1 may be implemented in or take other forms of vehicles, such as cars, recreational vehicles, trucks, buses, motorcycles, bicycles, mopeds, scooters, lawnmowers, agricultural vehicles, engineering vehicles, golf carts, and robotic vehicles. Other vehicles are also possible. The illustrated embodiment relates to a vehicle including four wheels, but vehicles having different numbers of wheels may be used, such as, but not limited to, tricycles, three-wheeled vehicles, patrol cars, motor scooters, truck vehicles including trailers, and the like. Furthermore, the CVT system 1 may be used in a vehicle coupled to a trailer, a semi-trailer, a truck, etc., wherein alternatively the wheels of the trailer and/or the semi-trailer may be regarded as additional wheels of the vehicle by the CVT system 1. The CVT system 1 may be arranged to consider the wheels of other coupled vehicles in a similar form to the wheels of the vehicle comprising the CVT system 1. It is also perceived that a plurality of CVT systems 1 are included in the vehicle.

Fig. 9 shows an exemplary schematic of the control strategy of CVT system 1. The road condition may be monitored using a camera and cloud of information acquired representing the road condition information. In addition, other sensors may also be employed to obtain better predictions of road condition information and/or to improve available road condition information available, for example, in memory and/or the cloud. In the controller or TCU 5, the general road conditions and the local road conditions are distinguished. Information representing road conditions, obtained using cameras and/or clouds, may be used by the TCU 5 to obtain local road condition information and general road condition information. The TCU 5 may use information acquired by other sensors in order to establish general road condition information. Based on the retrieved general and local road condition information, the TCU 5 is arranged for adjusting the clamping force or pressure adjustment of at least one friction element on the torque transmitting member 17. From the general road conditions obtained, the severity of the impact may be estimated or determined by the TCU 5. The severity of the impact may also be estimated or determined by the TCU 5 by using the obtained local road condition information. However, the local road condition information may be used to predict the impact time. The severity of the impact and the time of impact enable the TCU 5 to perform a clamping torque calculation, wherein the calculated or estimated result may be used to set the clamping force or pressure of at least one friction element 15, 16 on the torque transmitting member 17. The pressure setting is used to control the hydraulic actuation system 6 of the CVT system 1, wherein the hydraulic actuation system 6 has a first hydraulic line 7 connected to the first friction element 15 and a second hydraulic line 8 connected to the second friction element 16. The hydraulic pressure in the first hydraulic line 7 results in a first clamping force on a first friction element of the transmission 2, and the hydraulic pressure in the second hydraulic line 8 results in a second clamping force on a second friction element of the transmission 2.

In the embodiment shown, the clamping force is delivered by a hydraulic actuation system 6. However, other embodiments may include actuation by means of mechanical, electromechanical or electro-hydraulic systems.

The motor or engine 11 of the vehicle 24 comprising the CVT system 1 according to the invention may be or comprise any combination of an internal combustion engine and an electric motor. Other motors and engines are also possible, such as fuel cell motors. In some embodiments, motor 11 may include multiple types of engines and/or motors. For example, a gas-electric hybrid vehicle may include a gasoline engine and an electric motor. Other examples are also possible.

With respect to torque transmitting members, various embodiments including thrust belt transmissions are disclosed herein. However, different types of straps for CVT are known, such as dry belts, chain belts and thrust belts, which can be used in the invention according to the present application. Other types of CVT systems are also disclosed, the torque of which is transmitted based on friction elements controlled by one or more clamping forces, which may be a toroidal CVT, a ratchet CVT, a cone CVT, or other types.

It should be understood that the method may include computer-implemented steps. All of the above steps may be computer-implemented steps. Embodiments may comprise a computer device, wherein the processes are performed in the computer device and the invention extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source code or object code, or in any other form suitable for use in implementing a process according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a ROM, e.g. a CDROM or a semiconductor ROM, or a magnetic recording medium, e.g. a floppy disk or a hard disk. Furthermore, the carrier may be a transmissible carrier such as an electrical or optical signal conveyed via electrical or optical cable or by radio or by other means such as by the internet or the cloud.

Some embodiments may be implemented, for example, using a machine or tangible computer-readable medium or article which may store and, if executed by a machine, may cause the machine to perform a method and/or an instruction set of operations in accordance with the embodiments. Such a machine may include, for example, any suitable processing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The machine-readable medium or article may include, for example, any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory, removable or non-removable media, erasable or non-erasable media, writeable or re-writeable media, digital or analog media, hard disk drive, floppy disk, compact disk read Only memory (CD-ROM), compact disk recordable (CD-R), compact disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language.

The various embodiments may be implemented using hardware elements, software elements, or a combination of both. Examples of hardware elements may include processors, microprocessors, circuits, application Specific Integrated Circuits (ASICs), programmable Logic Devices (PLDs), digital Signal Processors (DSPs), field Programmable Gate Arrays (FPGAs), logic gates, registers, semiconductor devices, microchips, chip sets, etc. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, mobile applications, middleware, firmware, software modules, routines, subroutines, functions, computer-implemented methods, procedures, software interfaces, application Program Interfaces (API), methods, instruction sets, computing code, computer code, and the like.

Graphics and/or image/video processing techniques may be implemented in various hardware architectures. The graphics functions may be integrated in a chipset. Alternatively, a separate graphics processor may be used. For example, processing of images (still or video) may be performed by a graphics subsystem such as a Graphics Processing Unit (GPU) or a Vision Processing Unit (VPU). As yet another embodiment, the graphics or image/video processing functions may be implemented by a general purpose processor, including, for example, a multi-core processor. In another embodiment, the functionality may be implemented in a consumer electronic device. Embodiments are possible that use a combination of different hardware architectures.

In various embodiments, the controller may communicate using a wireless system, a wired system, or a combination of both. When implemented as a wired system, the system may include components and interfaces suitable for use with communication or wired communications media, such as input/output (I/O) adapters, physical connectors to connect the I/O adapter with a corresponding wired communications medium. When implemented as a wireless system, the system may include components and interfaces suitable for communicating over a wireless shared media, such as one or more antennas, transmitters, receivers, transceivers, amplifiers, filters, control logic, and so forth. Examples of wireless shared media may include portions of wireless spectrum, such as RF spectrum, and the like. Wireless communication devices may be included to transmit and receive signals using a variety of suitable wireless communication techniques. These techniques may involve communication across one or more wireless networks. Exemplary wireless networks include, but are not limited to, cellular networks, wireless local area networks (WLAN, cfr.wifi), wireless Personal Area Networks (WPAN), wireless Metropolitan Area Networks (WMAN), satellite networks, and the like. In communicating across these networks, the transmitter may operate according to one or more applicable standards in any version.

The invention is described herein with reference to specific examples of embodiments of the invention. It will be evident, however, that various modifications, changes, substitutions and alterations can be made hereto without departing from the broader spirit of the invention. For the purposes of clarity and conciseness of description, features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also contemplated and understood to fall within the scope of the invention as outlined by the claims. The specification, drawings, and examples are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The present invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, many of the elements described are functional entities that may be implemented as stand-alone or distributed components or in combination with other components in any suitable combination and location.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words "a" and "an" should not be interpreted as limited to "only one", but rather are used to mean "at least one", and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. A continuously variable transmission system for a vehicle, the continuously variable transmission system comprising:

-a transmission having two friction elements, wherein a first friction element is coupled to a second friction element by a torque transmitting member, the clamping force or pressure of at least one friction element on the torque transmitting member being adjustable;

a controller for retrieving information indicative of an upcoming road condition,

wherein the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member based on the information retrieved,

wherein the system is arranged to deliver a variable output speed and torque to one or more wheels coupled to the system, wherein the information taken indicative of road conditions is employed to determine an estimated interaction of at least one of the one or more wheels with an upcoming road,

wherein a plurality of wheels are coupled to the system, an estimated interaction with the upcoming road is determined for the plurality of wheels, wherein the estimated interaction is determined separately.

2. The continuously variable transmission system of claim 1, wherein the controller is arranged to predict a change in the transmission input and/or output torque based on the information retrieved and to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member in accordance with the predicted.

3. A continuously variable transmission system according to claim 1, wherein the controller is arranged to predict a moment in time at which the transmission input and/or output torque will change based on the information retrieved, and to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member in accordance with the predicted torque change.

4. The variable transmission system of claim 2, wherein the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the torque transmitting member if the predicted change in the transmission input and/or output torque exceeds a predetermined threshold level.

5. The continuously variable transmission system according to claim 1, wherein the controller is arranged for retrieving information representative of a road condition from a detector for detecting the road condition.

6. The continuously variable transmission system of claim 5, wherein the detector is arranged for determining the road condition in front of the vehicle.

7. The infinitely variable transmission system of claim 5, wherein the detector is disposed in the vehicle.

8. The infinitely variable transmission system of claim 5, wherein the controller is arranged for wireless communication connection to the detector.

9. Continuously variable transmission system according to claim 8, characterized in that the controller is arranged for communication with the detector, which detector is placed in another vehicle, which preferably travels in front of the vehicle comprising the continuously variable transmission system.

10. The infinitely variable transmission system of claim 8, wherein the controller is arranged for communication with the detector, the detector being positioned stationary relative to the road.

11. The continuously variable transmission system of claim 1, wherein the controller is arranged for communication with a network to retrieve the road condition information.

12. The variable transmission system of claim 11, wherein the network includes a memory storing the road condition information.

13. The continuously variable transmission system of claim 11, wherein the network is in communication with one or more detectors arranged for determining the road condition, the one or more detectors being placed stationary relative to the road and/or within a vehicle.

14. The variable transmission system of claim 11, further comprising a web server arranged to provide the road condition information to the controller.

15. The continuously variable transmission system of claim 14, wherein the network server is arranged for receiving an indication of a position of the controller from the controller and for communicating road condition information relating to the position of the controller to the controller.

16. The infinitely variable transmission system of claim 5, wherein the detector comprises an optical system and/or an acoustic system.

17. The continuously variable transmission system of claim 16, wherein the controller is arranged for analyzing an image provided by a camera for a characteristic indicative of the road condition.

18. The continuously variable transmission system of claim 1, further comprising a wheel speed sensor, and wherein the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the member further based on the detected wheel speed.

19. The continuously variable transmission system of claim 1, further comprising a tire pressure sensor, and wherein the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the member further based on the detected tire pressure.

20. The continuously variable transmission system of claim 1, further comprising a manual leveling sensor, and wherein the controller is arranged for adjusting the clamping force or pressure of the at least one friction element on the member further based on the detected leveling.

21. The continuously variable transmission system of claim 1, further comprising a steering angle sensor, and wherein the controller is arranged to adjust the clamping force or pressure of the at least one friction element on the member further based on the detected steering angle.

22. The continuously variable transmission system of claim 1, wherein the controller is arranged to identify when one or more additional wheels are coupled to the system, wherein the information taken indicative of road conditions is further employed to determine an estimated interaction of at least one of the additional wheels with an upcoming road.

23. A vehicle comprising a continuously variable transmission according to any one of claims 1-22.

24. A vehicle comprising the continuously variable transmission according to claim 7, and the detector.

25. A web server configured for delivering information representative of road conditions to a vehicle comprising the continuously variable transmission system of any one of claims 1-22.

26. A network server according to claim 25, characterized in that the network server is arranged for receiving information representing road conditions from one or more sensors.

27. The network server according to claim 25, wherein the network server is arranged for receiving information from a vehicle indicative of road conditions and/or clamping forces or pressures.

28. A network server according to claim 25, characterized in that the network server is arranged for receiving an indication of the position of the vehicle from a vehicle and for communicating information representing the road conditions at and/or near the vehicle position to the vehicle.

29. The web server of claim 25, wherein the web server has a memory associated with the web server, the memory storing information representative of road conditions.

30. A method of operating a continuously variable transmission system for a vehicle, the continuously variable transmission system including a transmission having first and second friction elements coupled by a torque transmitting member, the method comprising:

-setting an optimal clamping force or pressure of at least one friction element on the torque transmitting member;

-retrieving information representative of an upcoming road condition;

adjusting the clamping force or pressure of the at least one friction element on the torque transmitting member based on the information retrieved,

31. A storage medium having stored thereon a computer program product for operating a continuously variable transmission system for a vehicle, the continuously variable transmission system comprising a transmission having a first friction element and a second friction element coupled by a torque transmitting member, the computer program product comprising computer instructions which when executed by a processor perform steps comprising:

-providing a signal for setting an optimal clamping force or pressure of at least one friction element on the torque transmitting member;

-receiving information representative of an upcoming road condition; and

providing a signal for adjusting the clamping force or pressure of the at least one friction element on the torque transmitting member based on the information retrieved,