SE1351213A1 - Procedure and system for estimating acceleration of a vehicle - Google Patents

Abstract

The present invention provides a method for estimating an acceleration of a vehicle (100). The vehicle (100) comprises at least one drive wheel (113, 114), a motor (101) which can be disengaged in relation to said at least one drive wheel (113, 114), and a gearbox (103) which can be adjusted to a plurality of gear ratios. The method comprises, when the acceleration (faCc oPen) of said vehicle. (100) is to be estimated: - requesting a disengagement of the motor (101) from said drive wheel (113, 114) amounting to at least a first time (TI), - performing said disengagement of the motor (101) from said drive wheel (113, 114) for a time amounting to at least said first time (T) in connection with the gearbox (103) being switched from a first gear ratio to a second gear ratio, and - when the engine (101) has been disengaged from said drive wheels (113, 114), estimating the acceleration (faCc oPen) for the vehicle (100) .Fig. 2

Description

FIELD OF THE INVENTION The present invention relates to a method for estimating an acceleration of a vehicle according to the preamble of claim 1, and a system for estimating an acceleration of a vehicle according to the preamble of claim 17. The present invention also relates to a computer program and a computer program product, which implement the method according to the invention, as well as a vehicle.

Background of the Invention When it comes to vehicles in general, a variety of driveline configurations occur. For example. The gearbox can be a manually geared gearbox or an automatic gearbox.

Concerning heavy vehicles in particular, it is often unreasonable for these to be able to be driven in a way that is as comfortable as possible for the driver, which usually means that the gearboxes' gear changes should be carried out automatically by using the vehicle's steering system. This has also become increasingly common with automatically shifting gearboxes in heavy vehicles.

In the case of heavy vehicles, this automatic shifting often consists of a control system-controlled shifting of "manual" shift gears (also called AMT, Automated Manual Transmission), partly because these generally have a comparison with a conventional automatic shifting higher efficiency.

Regarding automatic gearboxes of the type that often occur in passenger cars, the efficiency is many times too low to be justified other than for use in e.g. city buses and distribution cars in cities, ddr frequent starts and stops are common. 2 In the case of heavy vehicles, which are largely used for road / motor vehicle use, are thus used where a control system-controlled shifting procedure is applied, usually automatically shifted "manual" shift loads.

Shifting of this type can take place in several different ways, and according to such a method an automatically controlled clutch is used for up / down gearing, whereby the driver thus only needs access to the accelerator pedal and brake pedal.

In principle, the clutch only needs to be used to start the vehicle from a standstill, cid other shifting can be performed by the vehicle's control system without the clutch being used at all by performing the shifts instead "torqueless", ie. the driveline torque is relieved so that the gearbox with closed clutch can be continued in neutral, whereby a new gear can be loaded and the torque transfer resumed.

Many times, however, from comfort shells and in order to be able to perform shifting more quickly, the automatically controlled coupling is used for all or essentially all upshifts and downshifts.

Regardless of how the shift is performed, however, a good knowledge of the vehicle's radiating mass is required for the shift to be performed in a safe and comfortable manner.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for estimating an acceleration of a vehicle. This object is achieved by a method according to claim 1.

The present invention relates to a method for estimating an acceleration of a vehicle, said vehicle comprising at least one drive wheel and a motor disengageable in relation to said at least one drive wheel for transmitting a driving force, said vehicle comprising a 3 to a plurality of gear ratios. installable gearbox, and wherein said method comprises estimating said acceleration for said vehicle when said engine is disengaged from said drive wheel.

The method comprises, when estimating said acceleration for said vehicle: requesting a decoupling of said engine from said drive wheel amounting to at least a first time, performing said decoupling of said engine from said drive wheel for a time amounting to at least said first time in connection with that said gearshift is shifted from a first gear ratio to a second gear ratio, and when said engine has been disengaged from said drive wheel estimating the acceleration of said vehicle.

Said estimated acceleration can e.g. is used in estimating the mass of the vehicle, where estimation of the mass of the vehicle can be based at least in part on said estimated acceleration. The present invention also relates to such a method.

The disengagement of said motor from said drive wheel can e.g. performed by opening a clutch or continuing a gearbox in a neutral layer.

Control system-controlled shifting of "manual" gearboxes, ie. automatically shifted manual gearboxes, are becoming increasingly common mom automotive industry. Common to switching with this type of driveline is that the driveline is opened, either by e.g. open a coupling or by continuing the gearbox in neutral, after which the gear unit is engaged and the driveline is closed again. 4 Ndr the powertrain is open racier inevitably a power outage, ie. driving force cannot be transmitted from the vehicle's engine to the vehicle's drive wheel. Such power outages are not natural due to natural shells, and can cause problems in e.g. driving a heavily loaded vehicle in a lock, where power outages can cause a deceleration that prevents e.g. an intended increase, e.g. due to the fact that the engine speed has time to drop to such a set speed that the intended shift cannot be performed. This is especially true for shifts shortly after starting from a standstill. Long power outages can also be undesirable for several other reasons, such as from the point of view of driver comfort and / or from a performance point of view, where vehicles with short power outages are perceived to show higher performance compared to vehicles where longer power outages are attenuated when changing.

The development of automatically shifted manual gearboxes is, among other things due to the above, in the direction of ever shorter power outages while maintaining comfort with the benefits this entails. However, these short power outages during switching can give rise to other problems.

Especially in the case of heavy vehicles, it is often important that a good estimate of the vehicle mass, ie. the vehicle's radiating weight, is available for the vehicle's steering system. This mass estimation can be used by several functions / systems that occur at the vehicle, and constitutes, among other things, an important parameter when changing. The vehicle mass can vary to a very large extent, especially in heavy vehicles. For example, the weight difference between an unladen vehicle and a fully loaded vehicle can be very large, and the weight of a fully loaded vehicle can be many times higher than the weight of the unladen vehicle.

Such a difference in weight of natural shells means that the vehicle will behave very differently when opening the driveline because the vehicle mass e.g. affects the vessel resistance of the vehicle, in particular the opening is performed in e.g. a closure or a closure, wherefore the vehicle's control system requires knowledge of the vehicle mass in order to e.g. switching must be able to be performed in a safe manner.

For this reason, heavy vehicles in particular often include functions for performing an estimation of the vehicle mass.

Such functions (methods) may include a comparison between the acceleration of the vehicle when the driveline is closed, ie. when the vehicle's engine is connected to the vehicle's drive wheel, or the vehicle's acceleration when the driveline Or is open, ie. when the vehicle's engine Or disengaged from the vehicle's drive wheel.

Due to the oscillations that occur in the driveline when opening / closing the same, especially in situations when a strong driving force (slow torque) is transmitted between the vehicle's engine and drive wheels, rapid shifting processes cause the driveline due to. for example torsional forces will not be force-relieved for a sufficiently long time for a correct estimation of the vehicle's acceleration at the opened driveline to be performed. This means that e.g. an estimation of the vehicle's mass where the vehicle's acceleration when the driveline is opened is used during fast shifting processes risks resulting in incorrect estimates of the vehicle's mass, with incorrect control of e.g. change process as follows.

According to the present invention, a method is provided for ensuring a good estimation of the vehicle's acceleration at an open driveline, whereby also a good estimation of e.g. the mass of the vehicle can be obtained.

According to the invention, this is solved by, when the vehicle Or is in motion and when an estimation of the vehicle's acceleration at 6 open driveline is to be performed, a required opening of the driveline is requested so that the driveline is open for at least a first time and the driveline has time to relieve force to the desired extent. This makes it possible that estimation of the vehicle's acceleration at the open driveline can be performed with a reduced risk of e.g. residual forces in the driveline with detrimental effect on the estimate.

The required application of the vehicle's driveline is carried out when changing gear at the said gearbox, ie. when changing from one gear ratio to another, whereby a normal, ie. When the vehicle mass is not to be estimated, faster axle processes are formed to take a longer time before the required estimation can be performed, where the shifting consists of an axle to be executed regardless of whether the vehicle mass is to be estimated or not, but thus with the difference according to the present invention take a longer time.

By requesting a required opening of the vehicle's driveline, ie. request a required decoupling of said engine from said drive wheel, it can according to the invention be suedes that a good estimation of the vehicle's acceleration and clamed e.g. the mass of the vehicle can also be discharged, where e.g. the estimation of the vehicle mass can then be used by the vehicle's control system. As will be appreciated, the acceleration of the vehicle at the open driveline can be both negative and positive, e.g. depending on the slope when the driveline is opened.

According to an embodiment of the invention, a plurality of required openings of the vehicle's driveline are requested, wherein at each opening of the driveline an estimation of the vehicle's acceleration is performed with the following estimation of the mass of the vehicle. These estimates of the vehicle mass can then be compared with each other to determine whether the desired accuracy of the vehicle mass estimation has been achieved. According to one embodiment, 7 openings of the driveline can thus be requested until the desired accuracy for the mass of the vehicle has been obtained.

According to an embodiment of the invention, the opening of the driveline can also be arranged to be carried out in other applicable cases, such as e.g. when the vehicle is driven with little or no driving force required from the vehicle's engine, such as e.g. when driving the vehicle in a downhill, or other situation when the demand for propulsion is small or none, as in e.g. Driving with a relaxed brake and accelerator pedal, respectively.

According to one embodiment, e.g. a first function for performing the estimation of the vehicle's acceleration at the open driveline, which e.g. can be generated by the function for estimating the mass of the vehicle, communicate with a second function. This second function can e.g. consists of the function used for opening the driveline, such as e.g. a function for controlling the gearbox and / or clutch. A request for extended opening of the driveline can be communicated from said first function to said second function, whereby then said second function can determine the appropriate time for opening the driveline and communicate when the driveline is opened to said first function, whereby estimation can be performed.

According to one embodiment, however, no such communication takes place, but the function for estimating the vehicle mass monitors, e.g. continuously or at suitably short intervals, the status of the driveline after a required opening has been requested, whereby estimation is performed when it is determined that the driveline has been opened.

Furthermore, it is not certain that the opening of the driveline which first follows the said request will amount to the said first time, but one or more shifts according to normal driving of the vehicle can be arranged to be performed before 8 e.g. The function for controlling the gear unit / coupling determines that a required opening can be carried out without undesired disadvantages in other respects.

Additional features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments and the accompanying drawings.

Brief Description of the Drawings Fig. 1A schematically shows a vehicle in which the present invention can be used.

Fig. 1B shows a control unit in the control system of the vehicle shown in Fig. 1A.

Fig. 2 shows an exemplary method according to the present invention.

Figs. 3A-B show how the torque of a vehicle driveline can vary during a shifting cycle.

Detailed Description of Embodiments Fig. 1A schematically shows a driveline in a vehicle 100 according to an embodiment of the present invention. The vehicle 100 schematically shown in Fig. 1A comprises a driveline with an internal combustion engine 101, folded in a conventional manner, via a shaft extending on the multi-combustion engine 101, usually via a swivel shaft 102, or connected to a gear shaft 103 via a clutch 106.

The internal combustion engine 101 is controlled by the control system of the vehicle 100 via a control unit 115. Similarly, the clutch 106, which in the present example consists of an automatically controlled clutch, and the gearbox 103 are controlled by the control system of the vehicle 100 by means of a control unit 116. A shaft 107 emanating from the gearbox 103 drives drive wheels 113, 114 via an end shaft 108, such as e.g. a conventional differential, as well as drive shafts 104, 105 connected to said end shaft 108.

According to the above, switching systems of the type shown in Fig. 1A, i.e. automatically shifted manual gearboxes, all the more common, where a lot of energy is put into reducing the shifting times to minimize driving of the vehicle without propelling torque.

Similarly, strong energy is put into estimating the vehicle mass in order to be able to adapt the vehicle's characteristics to prevailing conditions. A common method for estimating a vehicle mass involves the step of estimating the vehicle's acceleration with rod and open driveline, respectively, where estimation yid open driveline is performed in connection with shifting.

Such methods usually utilize the assumption that the vehicle's torque resistance is unchanged during the time the gear is engaged, and therefore the vehicle's acceleration at the open and closed driveline, respectively, to determine the weight of the vehicle.

The present invention relates to such methods for estimating a vehicle mass, and in particular to a method in which the acceleration of the vehicle is determined while the engine of the vehicle is disengaged from the drive wheels of the vehicle. Fig. 3A shows an example of how the torque M of a vehicle driveline can vary with the time t during a shifting process. At time take paborja's torque relief before opening the driveline, and at time to this has been taken out and the driveline is opened, e.g. by opening the clutch and / or continuing the gearbox in neutral. However, as shown in Fig. 3A, the driveline torque does not immediately nail, but due to e.g. Torsional forces exist, especially when high torque is transmitted from the motor 101, residual forces which result in a oscillation process. This is shown in more detail in Fig. 3B, where the time between tb and t is shown, and where the oscillations only at time tb, have decreased to such an extent that estimation can be considered to be performed with good accuracy. Similarly, oscillations occur when the powertrain again starts to close, indicated by when the driving force again begins to be transmitted so that at the time, for example in Fig. 3A, it is up to the level before shifting. Estimation of the vehicle's acceleration can thus only be performed in the interval to ensure possible estimation of the vehicle's acceleration at the Open driveline, and clamed e.g. best possible estimation of the mass of the vehicle, shall be obtained, where this time can be very short when shifting with today's fast and efficient shifting system.

Estimation of the vehicle's mass, etc., in particular when the vehicle's acceleration at the open driveline is to be determined, thus becomes more difficult when the shift times become alit shorter, which means that incorrect estimates of the acceleration and thus the mass are obtained.

The present invention provides a method of reducing the risk of incorrect estimates of vehicle acceleration at open driveline. This is achieved by requesting one or more required openings of the driveline, such as e.g. "Slow shifts".

An exemplary method 200 according to the present invention is shown in Fig. 2, where the method for estimating the acceleration of the vehicle is described in connection with a method according to the invention for estimating the mass of the vehicle, where the mass is estimated at least in part by estimating the vehicle acceleration at open driveline. The method 200 according to the present example Or arranged to be performed by a control unit 117 (shown in Fig. 1A). The control unit 117 can be constituted by any applicable control unit in the control system of the vehicle 11, and the function for estimating vehicle mass can also be implemented in several control units. Likewise, the estimation of the vehicle mass can be arranged to be performed by several control units simultaneously and individually. The invention can also be implemented in a control unit dedicated to the present invention.

Generally, control systems in today's vehicles consist of a communication bus system consisting of one or more communication buses for interconnecting a number of electronic control units (ECUs) as well as controllers, or controllers, 115, 116, 117, and various components arranged in the vehicle 100. Such a control system can comprise a large number of control units, and the responsibility for a specific function can be divided into more than one control unit. For the sake of simplicity, Fig. 1A shows only a very limited number of control units.

The function of the control unit 117 (or the control unit (s) to which the present invention is implemented) according to the present invention can e.g. may be due to signals from the control unit 116 which control the gear shaft / clutch, e.g. to know when the driveline has been reached. Similarly, signals can be output to the controller 116, e.g. in order to request an opening of the driveline amounting to at least a first time. The control unit 117 also requires signals regarding e.g. a wheel rotational speed or rotational speed of the output shaft of the gearbox or alternatively signals from an accelerometer to determine the acceleration of the vehicle at the open driveline. In general, control units of the type shown are normally arranged to receive sensor signals from different parts of the vehicle 100, as well as from different control units arranged in the vehicle 100. 12 The control is often controlled by programmed instructions. These programmed instructions typically consist of a computer program, which when executed in a computer or control unit causes the computer / control unit to perform the desired control, such as the method steps of the present invention.

The computer program usually forms part of a computer program product, where the computer program product comprises an applicable storage medium 121 (see Fig. 1B) with the computer program stored on said storage medium 121. Said digital storage medium 121 may e.g. consists of someone from the group: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk drive, etc., and be arranged in or in connection with the control unit, the computer program being executed by the control unit. By following the instructions of the other computer program, the behavior of the vehicle in a specific situation can thus be adapted.

An exemplary control unit (control unit 117) is shown schematically in Fig. 1B, wherein the control unit may in turn comprise a calculating unit 120, which can be constituted by e.g. any suitable type of processor or microcomputer, e.g. a Digital Signal Processor (DSP), or an Application Specific Integrated Circuit (ASIC). The calculating unit 120 Or connected to a memory unit 121, which provides the calculating unit 120 e.g. the stored program code and / or the stored data calculation unit 120 need to be able to perform calculations. The calculation unit 120 Or Above arranged to store partial or final results of calculations in the memory unit 121. 13 Furthermore, the control unit is provided with devices 122, 123, 124, 125 for receiving and transmitting input and output signals, respectively. These input and output signals may contain waveforms, pulses, or other attributes, which of the devices 122, 125 for receiving input signals may be detected as information for processing the calculation unit 120. The devices 123, 124 for sanding output signals are arranged to convert calculation results from the calculation unit. 120 to output signals may be transmitted to other parts of the vehicle control system and / or the component (s) for which the signals Or are intended. Each of the connections to the devices receiving and transmitting input and output signals, respectively, may be provided by one or more of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Oriented Systems Transport), or any other bus configuration; or by a wired connection.

Returning to Fig. 2, there is thus shown an exemplary method 200 according to the present invention for estimating the mass mf of the vehicle 100. The procedure begins in step 201, where it is determined whether an estimation of the mass 100 mf of the vehicle is required. If so, the procedure proceeds to step 202. The transition from step 201 to step 202 may be governed by one or more of a number of different criteria. For example. it may be considered that an estimation is required each time the engine 100 of the vehicle 100 is started after being switched off. According to one embodiment, estimation is considered required if the engine 101 of the vehicle 100 has been shut off for an extended period of time at some applicable time.

According to an embodiment of the invention, an estimation of the mass mf of the vehicle 100 is considered to be required if any system present at the vehicle 100 indicates a deviation from previous conditions. For example. can information from a 14 air suspension system or tire pressureSurveillance system due to. for example changed pressure levels indicate that a change of the vehicle's 100 load and thus mass mf may have been performed, whereby a new estimation of the vehicle 100 mass mf should be performed.

If it is determined in step 201 that it is determined that an estimation of the vehicle's mass 100 mf is required, the procedure proceeds to step 202, where it is determined whether an estimation of the vehicle's acceleration at the open driveline is to be performed, so this may constitute a step in estimating the vehicle mass. which is incorrectly estimated in a way that does not need to be described in more detail here. When estimating the acceleration of the vehicle is to be performed, the procedure proceeds to step 203, where a request for a required opening of the driveline is made. The definition of extended opening can e.g. is fixed-Land as a specific time, such as a first time T1, in the control system of the vehicle 100, whereby a request results in an opening time corresponding to at least said first time T. The extended opening can also be requested by explicitly requesting that the driveline be kept open during a certain time, such as e.g. a first time 11. This first time is a time that is longer than the time the driveline is normally open at the shaft, ie. when no desired Opening begars.

Begaran am required opening of the driveline can e.g. is controlled to the control unit 116 for controlling the gearbox, whereby the control unit 116 can provide for a prolonged opening of the driveline when deemed necessary, which can be determined by the control unit 116 and / or other applicable control unit. The control unit 116, which according to the above controls the coupling 106 according to the present embodiment, can e.g. Open the driveline by opening the clutch 106 and / or continuing the gearbox 103 in neutral. The driveline can e.g. Opens when it is determined that the opening of the driveline Or is applicable, which e.g. can be performed in connection with a changeover where the changeover process is allowed to take a longer time than normal, or at another applicable time, such as e.g. other vehicle 100 is driven in e.g. a downlink or forward without applied driving force of the combustion engine 101 and without applied braking torque.

When the driveline is opened, this may be arranged to be communicated by the control unit 116 for controlling the gear unit, either at the moment when the driveline is opened or e.g. with a warning before the actual opening of the driveline is carried out.

The control unit 117 may also be arranged to monitor the status of the driveline to determine when the driveline is opened, e.g. If this is not arranged to be communicated by the control unit 116. After the opening of the driveline has been requested in step 203, the procedure proceeds to step 204, where it is determined whether the driveline has been opened. As long as the driveline has not been reached, the procedure remains in step 204, while the procedure proceeds to step 205 when it is determined that the driveline has or will be opened for a short period of time.

In step 205, it is determined whether the driveline is considered to be force-relieved to an appropriate degree, ie. free from fluctuations due to e.g. the torsion which inevitably arises in particular during the transfer of large forces, and which will affect the propulsion of the vehicle 100 via the drive wheels 113, 114. This can e.g. is considered to be the case when a certain time, such as a certain number of hundredths or tenths of a second has elapsed since Opening, where this time Above e.g. may be arranged to be a function of the force which before opening of the driveline has ever been carried by it. The determination can also be performed based on e.g. signals from applicable sensors. If the driveline is considered free from undesired oscillations to an applicable extent 16, the procedure proceeds to step 206 for estimating the acceleration f -acc of the vehicle 100 when the driveline is open.

The process proceeds to step 207 to determine whether the estimation of the acceleration at the open driveline is final, and if so, the procedure may proceed to a step 208 in which a request to close the driveline may be made so as not to open the driveline openly. According to one embodiment, however, no such request is made. Estimation of the vehicle's 100 mass mf can then, as will be appreciated and as can be appreciated by those skilled in the art, be performed in the usual manner based on established driving forces and accelerations when the driveline is open or dangerous and / or after shifting, whereby a good estimate can be obtained.

In step 209 it is then determined whether one or more further estimates of the mass mf of the vehicle 100 are required.

This can e.g. is determined based on the result of the estimation of the vehicle mass mf, where the obtained estimate of the vehicle's 100 mass mf can be compared with previously obtained estimates, and am e.g. the variance between the obtained estimates meets the desired criteria, a reliable measure of the vehicle's 100 mass mf can be considered available. In such situations, no further estimate is thus required, whereby the procedure can be terminated in step 210. This can e.g. be the case when estimation is performed after the motor 101 of the vehicle 100 has been started from having been shut down, where the obtained estimate indicates that the vehicle 100 has the same weight as before the engine 101 was switched off, ie. the estimate obtained corresponds to previously received estimates, whereby it can be assumed that no loading / unloading has been performed during the time the engine 101 has been switched off.

If, on the other hand, in step 209 it is determined that additional estimates of the mass of the vehicle are required, e.g. due to the fact that the 17 obtained estimate of the mass of the vehicle deviates from the previously obtained estimate and / or the variance for the obtained estimate is still too high, the procedure returns to step 202 for flight estimation as above.

For example. In step 209, further estimation of the mass of the vehicle may be required if the accuracy estimate of the mass of the vehicle is considered to be correct. This can e.g. be the case am several estimates of the vehicle's 100 mass mf have been made, but where the respective results of these deviate to such an extent that no reliable value is considered to have been obtained. For example. the variance of the estimates obtained may be too star, and the accuracy may be less than any applicable accuracy.

Further estimation of the vehicle mass can also e.g. is considered required as long as a certain number of estimates have not been performed. For example. at least two, or an appropriately larger number, estimates of the mass of the vehicle may be provided to be performed. The need for further estimation of the mass of the vehicle can then be determined based on the said at least two estimates of the mass.

Estimation of the vehicle mass can thus be repeated as long as an estimate of the vehicle's 100 mass etc. has not been obtained with the desired accuracy.

The present invention has the advantage that a reliable estimation of the vehicle's 100 mass mf is possible by requesting longer openings of the vehicle's 100 driveline than what is normally used for shifting when driving the vehicle, whereby a good estimation of the vehicle's 100 mass mf can be performed with reduced risk. because residual energy in the driveline negatively affects the calculations.

When an estimate of the vehicle's 100 mass mf has been obtained with the desired accuracy, this estimation can then be applied during the remaining vehicle journey, whereby shifts during the journey 18 can be carried out with the shortest possible power outages with the advantages this entailed. The one or more extended openings of the driveline can thus be arranged to be made as far as possible at the beginning of the vehicle's travel, whereby e.g. Waxing during the remaining voyage can be performed entirely with respect to fast and efficient changing.

The driveline is opened as above for extended periods of time according to the present invention. This can be experienced as a comfort disturbance and / or concern of the driver of the vehicle as the vehicle will behave in an abnormal manner for the driver. According to one embodiment of the present invention, therefore, steps are taken to reduce such comfort disturbance / inconvenience. For example. the driver can be noticed that an estimation of vehicle mass is performed or will be performed, e.g. by appropriate message via appropriate instrument, such as e.g. by lighting a warning light or a message in clear text in the applicable display.

Alternatively, the extended opening time can e.g. be arranged to be "masked" by appropriate control of e.g. the combustion engine 101 to produce engine noise which results in the opening time of the driver being experienced as shorter than it is in practice. For example. For example, the internal combustion engine speed may be maintained at a slightly applicable speed and thus not be allowed to drop to an idle speed. The speed can e.g.

It must also be arranged to be controlled at the speed which the internal combustion engine will maintain after the final shifting earlier than what is actually required from the shifting point of view.

Furthermore, estimating the vehicle's acceleration at the open driveline has been described in connection with estimating a mass, but estimating the vehicle's acceleration at the open driveline according to the invention is equally applicable to other functions 19 where good estimation of the vehicle's acceleration at the open driveline is unsatisfactory.

The present invention is not limited to the above-described embodiments of the invention, but relates to and includes all embodiments within the scope of the appended independent claims.

Claims (21)

Patent claims A method for estimating an acceleration of a vehicle (100), said vehicle (100) comprising at least one drive wheel (113, 114) and a motor (101) disengageable in relation to said at least one drive wheel (113, 114) for transmitting a driving force, said vehicle (100) comprising a gearbox (103) installable to a plurality of gear ratios, and said method comprising estimating said acceleration (f -acc open) for said vehicle (100) when said engine (101) is disengaged from said drive wheel, characterized in that the method comprises, when said acceleration lf s-acc open) for said vehicle (100) is to be estimated: - requesting a disengagement of said engine (101) from said drive wheel (113, 114) to at least one first time (Ti), - performing said disengagement of said motor (101) from said drive wheel (113, 114) for a time amounting to at least said first time (Ti) in connection with said gearbox (103) being shifted from one first gear ratio to a second gear ratio, and - when said engine (101) has been disengaged from said drive wheel (113, 114), estimate the acceleration of said vehicle (100). The method of claim 1, wherein said shifting is a shifting from said first gear ratio to said second gear ratio intended to be performed regardless of whether said estimation of said acceleration is to be performed or not. (facc opcn) for 21 A method according to claim 1 or 2, wherein when shifting from said first gear ratio to said second gear ratio without said request to disengage said motor (101) from said drive wheel (113, 114), said motor (101) is disengaged from said drive wheel ( 113, 114) a time amounting to a second time (12), said second time (12) being a comparison with said first time (T1) shorter time. A method according to any one of the preceding claims, further comprising determining whether the drive wheels (113, 114) of the vehicle (100) have been substantially relieved by the action of said engine (101), and estimating the acceleration (f -acc open) of said vehicle. (100) when said drive wheel (113, 114) has been substantially relieved by the action of force from said motor (101). A method according to any preceding claim, further comprising performing a disengagement of said motor (101) from said drive wheel (113, 114) at least up to said first time (T1) when said vehicle (100) is driven with little or no from named engine (101) hegard propulsion. A method according to any one of the preceding claims, further comprising, at said request for a release of said motor (101) from said drive wheels (113, 114), - accustoming to a shift intended to be performed regardless of whether said estimation of said acceleration is to be performed or not, and - performing said decoupling of said motor (101) from said drive wheel (113, 114) for a time amounting to at least said first time (T1) in conjunction with said shifting. 22 A method according to any one of the preceding claims, further comprising, when estimating the acceleration of said vehicle (100), and when performing a first shift from said first gear ratio to said second gear ratio: 1. determining whether said engine (101) is to is disengaged from said drive wheel (113, 114) for a time of at least said first time (Ti) at said first shift, or only at a subsequent shift after said first shift, and 2. if said motor (101) is to be disengaged from said drive wheel (113, 114) a time amounting to At least said first time (T1) first at a following shift after said first gearing, perform said release of said motor (101) from said drive wheel (113, 114) for a time amounting to at least said first time (Ti) first at a puffing waxing. A method according to any one of the preceding claims, further comprising: - from a function for performing an estimation of a mass (mf) for said vehicle (100) initiating said request for a decoupling of said engine (101) from said drive wheel ( 113, 114) relating to At least said first time (TI), said function for performing said estimating the mass (mf) of said vehicle (100) being separated from a function for disengaging said motor (101) from said drive wheel ( 113, 114). The method of claim 8, further comprising determining a time for disengaging said engine (101) from said drive wheel (113, 114), and 1. communicating said set time to said 23 mass estimation function (mf) of said vehicle. (100). The method of claim 8 or 9, further comprising communicating from said function (99) 114 from said function of disengaging said engine (101) to said function of estimating the mass (mf) of said vehicle (100) when said motor (101) is disengaged from said drive wheel (113, 114) for a time at least amounting to said first time (T1). A method according to any one of the preceding claims, further comprising taking at least one action to reduce an impact on the vehicle driver caused by disengagement of said engine (101) from said drive wheel (113, 114) amounting to at least said first time (Ti) A method for estimating a mass of a vehicle (100), said vehicle (100) comprising at least one drive wheel (113, 114) and a motor (101) disengageable in relation to said at least one drive wheel (113, 114) for transmission of a driving force, said vehicle (100) comprising a gearbox (103) installable to a plurality of gear ratios, characterized in that the method comprises estimating said mass (md for said vehicle (100) at least partly based on an acceleration (f -acc open) estimated according to any one of claims 1-11. The method of claim 12, further comprising, once the mass (mf) of said vehicle (100) has been estimated: 1. determining whether further estimation of the mass (mf) of said vehicle (100) is required, and 2. requesting another disengaging said engine (101) from said drive wheel (113, 114) amounting to at least 24 said first time (Ti) for estimating the acceleration facc open (for said vehicle (100) when further estimating the mass (mf) of said vehicle ( 100) is required. A method according to any one of claims 12 or 13, further comprising: - requesting a plurality of disengages of said motor (101) from said drive wheel (113, 114) amounting to said first time (TI), each such disengagement of said motor (101) from said drive wheel (113, 114) an estimation of the acceleration (f. — acc open) for said vehicle (100), and by utilizing this an estimation of the mass (Ind for said vehicle (100), is performed, and - based on said estimates of the mass of the vehicle (Ind determine whether further estimation of the mass (Ind for said vehicle (100) is required. The method of claim 13 or 14, further comprising determining an accuracy for the estimation of the mass (mf) of said vehicle (100), and performing a further estimation of the mass (Ind for said vehicle (100) if said determined accuracy is less than one understand accuracy. A method according to any one of claims 12-15, further comprising performing further estimations of the mass of the vehicle (Ind until the accuracy of the estimation of the mass of the vehicle (mf) meets a first accuracy. A method according to any one of claims 12-16, further comprising determining whether an estimation of the mass (mf.) Of said vehicle (100) is to be performed, and, performing said estimating the acceleration of said vehicle when estimating the mass (ITO for said vehicle 100. shall be carried out. A computer program comprising program code, which when said program code is executed in a computer, causes said computer to execute the method according to any of claims 1-17. A computer program product comprising a computer readable medium and a computer program according to claim 18, wherein said computer program is included in said computer readable medium. A system for estimating an acceleration for a vehicle (100), said vehicle (100) comprising at least one drive wheel (113, 114) and a motor 101 disengaging in relation to said at least one drive wheel (113, 114). of a driving force, said vehicle (100) comprising a gear unit (103) installable to a plurality of gear ratios, and said acceleration lf, -acc open) for said vehicle (100) being arranged to be estimated when said engine (101) is disengaged. from said drive wheel, characterized in that the system comprises means adapted to estimate, when said acceleration (face open) for said vehicle (100): - requesting a disengagement of said motor (101) from said drive wheel (113, 114) amounting to at least a first time (Ti), - performing said disengagement of said motor (101) from said drive wheel (113, 114) for a time amounting to at least said first time (Ti) in connection with said gearbox (103) being shifted from a first out shifting to a second gearing, and - when said engine (101) has been disengaged from said 26 drive wheels (113, 114), estimate the acceleration lf. — acc open) for said vehicle (100). Vehicle (100), characterized in that it comprises a system according to claim 20. FIG. 'IA 13 1 .--- 104 103? , ---- 108? 1i10 (16 101) 107 .---- 2/4