Patent Description:
The general inventive concept can be applied in heavy-duty vehicles, such as trucks, buses and construction equipment. Although the invention will be described with respect to a heavy-duty vehicle, the general inventive concept is not restricted to this particular vehicle, but may also be used in other vehicles such as cars.

There is an ongoing effort in the heavy-duty vehicle industry towards improving the fuel economy of the vehicles and to provide vehicles that are more environmentally friendly. These aspects are oftentimes also considered by the drivers, in particular professional drivers of heavy-duty vehicle. Some drivers may have a driving style which results in lower fuel consumption than other driving styles. For examples, it has been common practice among drivers of heavy-duty vehicles to shut off the internal combustion engine when the vehicle is travelling along a downwardly sloping road segment in order to rely on freewheeling of the vehicle, thereby reducing the fuel consumption and environmental impact. The vehicle industry has also been considering control strategies in which the internal combustion engine is temporarily shut off under certain circumstances to reduce fuel consumption. However, when the internal combustion engine is turned on again, the drivability and productivity may be negatively affected, and the driver may perceive an unsatisfactory driving experience. Thus, there is still room for improvement in this regard.

The document <CIT> is known and describes a method of controlling a hybrid vehicle which includes steps of determining a first torque, the first torque being a currently required torque, determining a second torque to be generated at a near-future time, or a predicted acceleration at the near-future time, determining a predicted speed at the near-future time based on a current speed and the second torque or the predicted acceleration, determining when it is determined that one of engine start and shift conditions is satisfied at a current time based on at least one of the first torque and the current speed, whether the remaining one of the engine start shift conditions is satisfied at the near-future time, and controlling an event corresponding to the satisfied condition at the current time is delayed or an event corresponding to the satisfied condition at the near-future time is advanced when the remaining one condition is satisfied.

An object of the invention is to provide a method which at least partly alleviates the drawbacks discussed above. This and other objects, which will become apparent in the following discussion, are achieved by a computer-implemented method as defined in the accompanying independent claim <NUM>. Some non-limiting exemplary embodiments are presented in the dependent claims.

The inventors of the general inventive concept have realized that by predicting a driving scenario for an upcoming road segment, the internal combustion engine may be started on an appropriately selected gear based on the prediction, and thereby enabling improved drivability, productivity and driver experience.

According to at least a first aspect of the present disclosure, there is provided a computer-implemented method for clutch start control of an internal combustion engine, ICE, in a vehicle, the method comprising:.

As mentioned above, by starting the ICE on a gear which has been selected based on a predicted driving scenario, which in turn is based on look-ahead information, the drivability, productivity and driver experience may be improved. It should be understood that the present disclosure envisages providing positive torque in some driving scenarios, and providing negative torque in other driving scenarios. When starting the ICE on a gear, the clutch is activated in a normal manner. The clutch needs a torque when activated, and with the computer-implemented method an appropriate torque is provided by the above gear selection.

The topographic data may suitably be obtained by a GPS system or a similar positioning system of the vehicle. As an example, the acquired data may cover several kilometres of the upcoming road, such as >~<NUM> kilometres, for example <NUM>-<NUM> kilometers. Thus, the acquired topographic data will in each instance normally include topographic data for a limited length of the road as a whole, i.e. the topographic data will include information about an upcoming road segment. Suitably, as the vehicle travels on that road segment, new topographic data may be acquired, for a new upcoming road segment. The new upcoming road segment may at least partly overlap the previous road segment. Thus, it should be understood that the step of acquiring topographic data may be performed repeatedly, either continuously or at certain time intervals (for example every second).

The topographic data may suitably be acquired by a control unit which may be operatively connected to the positioning system of the vehicle. Thus, the control unit may acquire the topographic data by means of the positioning system.

As will be readily understood, the upcoming road segment covered by the acquired topographic data may have varying topography. For instance, one or more parts of the upcoming road segment may be uphill, one or more parts may be downhill, and one or more parts may be substantially flat. Such different topographies may call for different driving scenarios. For example, in case of an uphill part of the road segment, it may be predicted that the ICE should be turned on before reaching that part of the road segment, or that a certain power/torque may be required to effectively operate the ICE. On the other hand, in case of a downhill part of the road segment, it may predicted that engine braking should be activated. Thus, it will be understood that for different driving scenarios, starting the ICE on a certain gear may be more appropriate than on another gear.

According to at least one exemplary embodiment, the method comprises:.

It should be understood that this may be relevant for different driving scenarios. For, example, in case of a predicted loss of speed due to a hill climb, the ICE is started on a gear to ensure that the vehicle speed is maintained within the desired speed range. Conversely, in case the vehicle is gaining speed when riding downhill and it is predicted that the vehicle speed will exceed the upper limit of the desired speed range unless the brakes are applied or engine braking is performed, then the ICE may be started on an appropriate gear, and may suitably be downshifted for engine braking. In order to achieve a good drivability the engaging gear may be selected accordingly. Nevertheless, the gear may be quickly shifted from the initially selected gear for further controlling the vehicle, e.g. a quick downshift for engine braking. In this connection it should be noted that drivability is not only limited to the perceived feeling for the driver, but may also include adaptation to the traffic flow and achieving good productivity.

The above exemplary embodiment is based on a prediction that the vehicle speed may in the near future fall below the lower limit of the desired speed range or exceed the upper limit of the desired speed range, and that in anticipation of such an undesired event, the ICE is appropriately controlled to counteract that the predicted undesired event takes place. Nevertheless, according to at least some exemplary embodiments, a similar principle may be applied even if no prediction has been done, and yet it is detected that the vehicle speed has reached a value outside the desired speed range. This provides for an additional safety measure, and is reflected in the below presented exemplary embodiment.

Thus, according to at least one exemplary embodiment, the method comprises:.

This is advantageous as it provides for a back-up control strategy, in case the change in speed was not predicted. It may also be conceivable that this exemplary embodiment has a narrower or wider defined desired speed range than the previous prediction-based exemplary embodiment, in which case both control strategies for the ICE may operate in parallel but with different defined desired speed ranges.

According to at least one exemplary embodiment, the step of predicting a driving scenario comprises predicting an acceleration of the vehicle or predicting a provision of propulsion power/torque to the vehicle, wherein the step of selecting a gear comprises:.

This is advantageous because when it can be predicted that the vehicle will need an acceleration or propulsion torque/power to be applied, then it is desirable if as much as possible of the available kinetic energy can be maintained. However, starting the ICE and engaging a gear will inherently result in some loss of kinetic energy, but by determining (e.g. by means of estimations, look-up tables, calculations, or similar) which one of the gears will result in the lowest loss of kinetic energy upon engagement, an energy efficient control may be achieved. For instance, if the vehicle is approaching a steep hill, it may be desirable to accelerate the vehicle before the climb, the ICE may therefore be started at a relatively high gear to maintain and accelerate the vehicle (with a possible upshift) and when starting the climb it may be followed by a downshift.

According to at least one exemplary embodiment, the step of predicting a driving scenario comprises predicting a braking of the vehicle, wherein the step of selecting a gear comprises:.

Thus, in contrast to the previous acceleration case, in the present exemplary embodiment, you want to lose as much kinetic energy as possible when engaging the gear in order to decelerate the vehicle.

From the above two exemplary embodiments it should now be understood that by appropriately selecting a gear based on a predicted operation of the vehicle, an advantageous control strategy is obtainable. The selection of the gear may, as mentioned above, be based on input with respect to parameters that affect the power need of the ICE.

According to at least one exemplary embodiment, the at least one parameter is one or more of the following parameters:.

This parameters may suitably be acquired by appropriate sensors, such as speed sensor and vehicle sensors. The curvature and inclination of the road may be acquired by cameras, lidars, radars, etc. or from map data. Other parameters may include distance to other vehicles or objects on the road.

According to the first aspect of the present disclosure, the method comprises determining which gear was previously engaged before the ICE was turned off, wherein said step of starting the ICE on the selected gear is followed by performing a gear shift to said previously engaged gear. This may be advantageous on, for instance, a substantially flat part of the upcoming road segment, wherein the vehicle is travelling at a certain speed, and the ICE is started at a selected gear which minimizes kinetic loss (often a high gear), after which a shift may be made to the previously engaged gear. The gear shift may suitably be a downshift from the selected gear to the previously engaged gear. Other examples may be that the vehicle travels in a pulse-and-glide operating mode, and/or the ICE is in a turned off state when reaching a curve, wherein the ICE is turned on or kept off, engaging a selected gear for taking the curve, and when the vehicle has exited the curve a gear shift back to the previously engaged gear may be made.

It should be understood that the general inventive concept may be implemented in connection with various different predictable driving scenarios, based on which prediction an appropriate gear is selected in association with starting the ICE. Some non-limiting examples of such driving scenarios include:.

It should be understood that the above non-limiting examples are just to mention a few driving scenarios in which the general inventive concept may be implemented, but there are of course others as well. For instance, the pulse-and-glide operating mode is not limited to substantially flat parts of upcoming road segments, but such an operating mode is also conceivable on non-flat parts, such as downhill, uphill, etc..

According to at least one exemplary embodiment, the method is performed when the vehicle is in a cruise control mode for automatically controlling the speed of the vehicle. Indeed, the method may suitably form part of a cruise control mode strategy, wherein a desired speed range is kept, allowing temporary shutting off of the ICE, in combination with prediction of driving scenarios for upcoming parts of road segments, based on which prediction an appropriate gear is selected for starting the ICE. When referring to starting the ICE, this may simply include engine rotation, with or without fuel combustion. Starting the ICE may for example include using the ICE for forward propulsion or for engine braking.

According to a second aspect of the present disclosure there is provided a computer program comprising program code means for performing the steps of the method according to the first aspect, including any embodiment thereof. The advantages of the computer program of the second aspect are largely analogous to the advantages of the method of the first aspect, including any embodiment thereof.

According to a third aspect of the present disclosure, there is provided a computer readable medium carrying a computer program comprising program code means for performing the steps of the method according to the first aspect, including any embodiment thereof, when said program product is run on a computer. The advantages of the computer readable medium of the third aspect are largely analogous to the advantages of the method of the first aspect, including any embodiment thereof.

According to a fourth aspect of the present disclosure, there is provided a control unit for controlling clutch start of an internal combustion engine, ICE, in a vehicle, the control unit being configured to perform the steps of the method according to the first aspect, including any embodiment thereof. The advantages of the control unit of the fourth aspect are largely analogous to the advantages of the method of the first aspect, including any embodiment thereof.

It should be understood that the control unit may control the ICE based on torque, using torque sensors or based on calculations/estimations. Another possibility, however, is that the control unit controls the ICE based on power (torque x rpm). While both methods of control are conceivable, they may have different response times.

The control unit may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The control unit may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where it includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device.

According to a fifth aspect of the present disclosure, there is provided a vehicle comprising a control unit according to the fourth aspect, including any embodiment thereof. The advantages of the vehicle of the fifth aspect are largely analogous to the advantages of the control unit of the fourth aspect, including any embodiment thereof.

All references to "a/an/the part, element, apparatus, component, arrangement, device, means, step, etc." are to be interpreted openly as referring to at least one instance of the part, element, apparatus, component, arrangement, device, means, step, etc., unless explicitly stated otherwise. Further features of, and advantages with, the present inventive concept will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present inventive concept may be combined to create embodiments other than those described in the following, without departing from the scope of the present inventive concept, which is defined by the appended claims.

<FIG> illustrates schematically a vehicle <NUM> comprising an internal combustion engine <NUM> in accordance with at least one exemplary embodiment of the present disclosure. In this example, the vehicle <NUM> is a heavy-duty vehicle in the form of a tractor unit, powered by an internal combustion engine <NUM>. However, the teachings of the present disclosure may also be implemented in other types of vehicles powered by an internal combustion engine, such as busses, construction equipment and passenger cars.

<FIG> illustrates schematically another vehicle <NUM> in accordance with at least one exemplary embodiment of the present disclosure, wherein the vehicle <NUM> is travelling on a road <NUM>. More specifically, the illustrated vehicle <NUM> is a heavy-duty vehicle combination which comprises a towing vehicle and a trailer which is towed by the towing vehicle. The towing vehicle is here illustrated in the form of a truck, powered by an internal combustion engine, and the trailer is illustrated in the form of a full trailer. It should however be understood that in other exemplary embodiments the trailer may be a semi-trailer. It should further be understood that the general inventive concept is not limited to heavy-duty vehicle combinations, but may be implemented for single vehicles as well, such as for a single heavy-duty vehicle, for instance a truck, which does not necessarily need to have a trailer connected. It should furthermore be understood that the teachings of the present disclosure may be implemented for driver-operated vehicles as well as for autonomous (self-driving) vehicles. Moreover, it should be understood that general inventive concept does not exclude an auxiliary or additional propulsion system (for example, electric) in addition to the internal combustion engine.

<FIG> illustrates schematically vehicle components that may be included when performing the computer-implemented method according to at least some exemplary embodiments of the present disclosure. A vehicle, such as the ones in <FIG> or <FIG>, is powered by an internal combustion engine, ICE <NUM>. The vehicle also comprises a transmission system <NUM>, which may be any conventional transmission system. The transmission system <NUM> can be operated to provide different gear ratios (gears <NUM> symbolically indicated). A clutch (not illustrated), when started, i.e. in its coupled state, provides a mechanical linkage between the ICE <NUM> and the transmission system <NUM>. The vehicle further comprises a control unit <NUM>, which is operatively connected to the transmission system <NUM> for selecting appropriate gear ratios when the vehicle is traveling on the road. The control unit <NUM> is also operatively connected to the ICE <NUM> and may control the ICE <NUM> so that it is shut off during travel and turned back on again during travel. The vehicle may additionally comprise a positioning system <NUM>, such as a GPS system. The control unit <NUM> may, by means of the positioning system <NUM>, acquire topographic data representative of the topography of an upcoming road segment. In <FIG> such an upcoming road segment <NUM> has been indicated. The general inventive concept is not limited to a particular length of such an upcoming road segment <NUM>, but as an illustrative example, it may typically be a couple of kilometres. However, longer or shorter settings of upcoming road segments may be conceivable without departing from the general idea of this disclosure. As illustrated in <FIG> an upcoming road segment <NUM> may include a number of different parts, which may be associated with different driving scenarios. In <FIG>, the vehicle is currently travelling on a substantially flat part <NUM>, but will soon reach an uphill part <NUM>, then a crest <NUM>, and the a downhill part <NUM>. Although <FIG> illustrates different parts <NUM>, <NUM>, <NUM>, <NUM> of the upcoming road segments <NUM>, there may of course be cases when the upcoming road segment (for which topographic data has been acquired by the control unit <NUM>) will have much less variation, such as for instance a long, straight and substantially flat upcoming road segment. Thus, it will be understood that the control unit <NUM> will repeatedly be acquiring new topographic data as the vehicle <NUM> progresses along the road <NUM>, wherein new topographic data representative of a new upcoming road segment may at least partly overlap with the previously acquired data (previous upcoming road segment <NUM>). This acquiring of topographic data may, for instance, be performed in a continuous manner or at certain time intervals. Furthermore, the acquiring of topographic data may be performed irrespectively of if the ICE <NUM> is in shut off or is turned on.

The control unit <NUM> may determine to shut off the ICE <NUM> for reducing energy consumption and reducing the impact on the environment. For instance, this may be the case when the road <NUM> has a slightly positive inclination and the vehicle speed can be maintained within a desired vehicle speed without any propulsion power from the ICE <NUM>. Suitably, the control unit <NUM> may receive sensor input data from a plurality of different sensors <NUM>, including speed sensor, weight sensor, proximity sensors, etc..

The control unit <NUM> may, based on the acquired topographic data, predict a driving scenario for at least a part of the upcoming road segment <NUM>. For instance, in the example illustrated in <FIG>, the control unit <NUM> may predict that the ICE <NUM> will need to be powered in order for the vehicle <NUM> to effectively drive in the uphill part <NUM> of the upcoming road segment <NUM>. Assuming the ICE <NUM> is currently in a shut off state, the control unit <NUM> may select a gear <NUM> which is appropriate for the predicted driving scenario. In for example this case, the control unit <NUM> may suitably, when turning on the ICE <NUM> before arriving to the uphill part <NUM>, select a gear ratio which results in the lowest loss of kinetic energy. This is beneficial since you want to maintain as much as possible of the available kinetic energy when arriving starting the climb. Thereafter, the control unit <NUM> may determine to downshift to a lower gear to effectively drive along the uphill part <NUM>.

In contrast to <FIG>, in a situation in which the vehicle <NUM>, with its ICE <NUM> turned off would approach a downhill part (e.g. part <NUM> or another downhill part), the control unit <NUM> may instead predict a driving scenario which includes engine braking. In such case, the control unit <NUM> may instead select a gear ratio which results in the highest loss of kinetic energy when starting the ICE <NUM>, in order to effectively decelerate the vehicle <NUM>. It should be understood that there are various conceivable driving scenarios, to which the control unit <NUM> may adapt its control of the ICE <NUM> and the selection of the appropriate gear <NUM>. Some non-limiting examples are given below:.

From the above it should thus be understood that there are various conceivable driving scenarios in which the computer-implemented method of the present disclosure may be implemented, e.g. by means of the control unit <NUM>. From the above, it can also be understood that the herein disclosed method for clutch start control of an ICE <NUM> may include providing a positive torque or a negative torque.

Turning now to the schematic charts in <FIG>, some different steps of non-limiting exemplary embodiments of the computer-implemented method of the present disclosure are illustrated. The computer-implemented method may suitably be performed by means of one or more control units, such as the control unit <NUM> illustrated in <FIG> or <FIG>.

<FIG> illustrates schematically a computer-implemented method <NUM> in accordance with at least one exemplary embodiment of the present disclosure. More specifically, <FIG> illustrates a computer-implemented method <NUM> for clutch start control of an internal combustion engine, ICE, in a vehicle, comprising:.

<FIG> illustrates schematically a computer-implemented method <NUM> in accordance with at least another exemplary embodiment of the present disclosure. This exemplary embodiment may include all the steps S1-S4 of the method <NUM> and additionally include the illustrated steps S5-S7. Thus, the method <NUM> may comprises:.

The control unit <NUM> may suitably have access to an internal or external memory in which a current desired speed range is stored. This may, for example, be part of a cruise control system of the vehicle. A speed sensor, such as one of the sensors <NUM> illustrated in <FIG>, may provide speed input signal to the control unit <NUM> with respect to the current vehicle speed. With look-ahead information obtained through the topography data acquired by means of the positioning system <NUM> and other parameters, such as the weight of the vehicle (obtainable by a weight sensor) and the current vehicle speed, the control unit <NUM> may predict at approximately what point along the road the vehicle speed will drop below or exceed the desired speed range, and may counteract this by turning on the ICE <NUM> and control it appropriately (e.g. providing positive torque or negative torque, respectively).

In an alternative interpretation of <FIG>, instead of the prediction in step S6, the step S6 may comprise: detecting that the speed of the vehicle has reached a value outside of said desired speed range when said vehicle has reached said part of the road segment. As a consequence, step S7 may in such case comprise: controlling the ICE so as to return the vehicle speed to a value within said desired speed range when travelling on said part of the road segment.

<FIG> illustrates schematically a computer-implemented method <NUM> in accordance with yet another exemplary embodiment of the present disclosure. This exemplary embodiment may include all the steps S1-S4 of the method <NUM>, and additionally include the illustrated steps S8-S10. Steps S8-S10 may actually be substeps to step S3, as will be explained. Furthermore, the method <NUM> may additionally include the steps S5-S7 of method <NUM>.

In the previously discussed method <NUM>, the step of predicting a driving scenario (step S2) may, for example, comprises predicting an acceleration of the vehicle or providing propulsion power/torque (positive torque) to the vehicle. In such case, the step of selecting a gear (step S3) may suitably comprise:.

In an alternative interpretation of <FIG>, in other cases, in the previously discussed method <NUM>, the step of predicting a driving scenario (step S2) may comprise predicting a braking of the vehicle (i.e. providing a negative torque). In such cases, the step of selecting a gear (step S3) may comprise:.

The parameter data acquired in step S8 may be related to one or more of the following parameters:.

The last two examples (radius of curvature and angle of inclination) may, for example, be obtained from the acquired topographic data. However, such parameters may also be obtainable by means of sensors and/or cameras, for instance.

As mentioned previously in this disclosure, the computer-implemented method, such as the methods <NUM>, <NUM>, <NUM> illustrated in <FIG>, may comprise: determining which gear was previously engaged before the ICE was turned off, wherein said step of starting the ICE on the selected gear is followed by performing a gear shift to said previously engaged gear. Said gear shift may, for example, be a downshift from the selected gear to the previously engaged gear.

<FIG> schematically illustrates a control unit <NUM> according to at least one exemplary embodiment of the present disclosure. In particular, <FIG> illustrates, in terms of a number of functional units, the components of a control unit <NUM> according to exemplary embodiments of the discussions herein. The control unit <NUM> may be comprised in any vehicle disclosed herein, such as the ones illustrated in <FIG> and <FIG>, and others discussed above. Processing circuitry <NUM> may be provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.

Particularly, the processing circuitry <NUM> is configured to cause the control unit <NUM> to perform a set of operations, or steps, such as the method discussed in connection to <FIG> and/or <FIG> and exemplary embodiments thereof discussed throughout this disclosure. Thus, the processing circuitry <NUM> is thereby arranged to execute exemplary methods as herein disclosed.

The control unit <NUM> may further comprise an interface <NUM> for communications with at least one external device such as the positioning system <NUM>, the sensors <NUM>, the transmission system <NUM>, and the ICE <NUM> discussed herein. As such, the interface <NUM> may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.

Claim 1:
A computer-implemented method (<NUM>, <NUM>, <NUM>) for clutch start control of an internal combustion engine, ICE (<NUM>), in a vehicle (<NUM>, <NUM>), comprising:
- when the vehicle is travelling on a road (<NUM>) with the ICE being shut off, acquiring (S1) topographic data representative of the topography of an upcoming road segment (<NUM>) ,
- predicting (S2) a driving scenario for at least a part (<NUM>, <NUM>, <NUM>, <NUM>) of the upcoming road segment based on the acquired topographic data,
- selecting (S3) a gear (<NUM>) based on the predicted driving scenario,
- starting (S4) the ICE on the selected gear before or when the vehicle reaches said part of the upcoming road segment,
characterized by:
- determining which gear was previously engaged before the ICE was turned off, wherein said step of starting the ICE on the selected gear is followed by performing a gear shift to said previously engaged gear.