WO2006033612A1

WO2006033612A1 - Engine-driven vehicle with transmission

Info

Publication number: WO2006033612A1
Application number: PCT/SE2005/001314
Authority: WO
Inventors: Anders Eriksson; Anders Lindgren; Magnus Lindau
Original assignee: Volvo Lastvagnar Ab
Priority date: 2004-09-24
Filing date: 2005-09-09
Publication date: 2006-03-30
Also published as: CN100480552C; SE0402323D0; SE0402323L; EP1797356A4; EP1797356A1; CN101027508A; SE526514C2; BRPI0516029A

Abstract

The invention relates to an engine-driven vehicle comprising at least one engine (10), and control elements (45; 48) designed to control a transmission (90) that can be driven by the engine, the control elements being designed to receive a first signal transmitted from a first sensor (115) and containing information on the gradient of the vehicle running surface, and to receive a second signal transmitted from a second sensor (110; 113) and containing information on the torque, and to receive a third signal transmitted from a third sensor (114) and containing information on the vehicle acceleration, in which the control elements are further designed to calculate the mass (m(i); m ) as a function of the first, second and third signals, and to control the transmission as a function of the vehicle mass calculated.

Description

JS, case 14896, 2005-06-07

Engine-driven, vehicle with transmission

The present invention relates to a motor vehicle comprising an engine and control elements, which are designed to control a transmission that can be driven by the engine.

The invention also relates to a method of calculating the mass of the engine-driven vehicle.

The invention ^' also relates to a computer program for performing said method.

State of the art

In vehicles having automatic, planetary gear-based transmissions with torque converters or semiautomatic stage-geared transmissions it is important to use an estimate of the vehicle mass that is accurate enough to provide optimum gear shift schemes according to certain given criteria, such as low fuel consumption or high average speed, for example.

One disadvantage of the state of the art is that the most suitable gear is not always selected in, for example, the first gear shift after starting, and especially if there has been a change in the vehicle load when the vehicle was at a standstill- There is therefore a need in certain situations to obtain an early and/or better estimate of the vehicle mass.

JP 2002-81989 describes a system for estimating vehicle weight, based on values for acceleration and motive force.

WO 03/041988 relates to estimation of the mass before gear shifts whilst underway. WO 02/087917 and WO 03/058093 relate to the selection of a starting gear. Summary of the invention

An object of the invention is to provide a motor vehicle in which a better estimate of the mass of the vehicle and thereby also of the rolling resistance is obtained.

Another object of the invention is to identify a cost- effective way of obtaining an improved basis for controlling the transmission.

The aforementioned objects are achieved by an engine- driven motor vehicle comprising at least one engine, and control elements designed to control a transmission that can be driven by the engine, the control elements being designed to receive a first signal transmitted from a first sensor and containing information on the gradient of the vehicle running surface, and to receive a second signal transmitted from a second sensor and containing information on the torque, and to receive a third signal transmitted from a third sensor and containing information on the vehicle acceleration, the control elements being further designed to calculate the mass of the vehicle as a function of the first, second and third signals, and to control the transmission as a function of the vehicle mass calculated.

This serves to prevent incorrect gear shifts when the vehicle is being driven.

The use according to the invention of existing components present on the vehicle gives more accurate information, which is used as a basis for decisions for cost-effective control of the transmission.

Said calculation is preferably performed as a function of predetermined information, which includes the rolling resistance constant, the air resistance constant, the acceleration due to gravity, the vehicle rear axle transmission ratio, the vehicle gearbox transmission ratio and the efficiency on the vehicle drivetrain and the wheel radius. This affords the advantage that a good estimate of the vehicle mass can be quickly and correctly obtained, since these values are already available for inclusion in the calculation of the vehicle mass. This also provides greater accuracy of information that is to be used as a basis for decisions for controlling the transmission.

The calculation of the vehicle mass is preferably also performed as a function of the vehicle speed.

According to the invention the vehicle achieves better driving performance since control of the transmission is based on more correct information. The vehicle can thus be driven in a manner which affords better fuel economy.

A further advantage of the invention is that shifting up to a gear which gives inadequate motive force is avoided. Yet another advantage is that the invention is well-suited both to automatic transmissions and to semiautomatic transmissions, that is to say both with and without interruption of power during acceleration, for example.

Brief description of the drawings

Fig. 1 shows a schematic representation of an engine- driven vehicle and a control system for this.

Fig. 2 shows a lead with examples of detected or calculated data, some of which are used according to the invention. Fig. 3a shows a schematic representation of how the gradient of a vehicle running surface is defined according to one embodiment of the invention.

Fig. 3b shows a schematic representation of how the gradient of a vehicle running surface is defined according to one embodiment of the invention.

Fig. 3c shows a table of measured and calculated data that is used according to one embodiment of the invention.

Fig. 4a shows a flow chart illustrating a method according to the invention.

Fig. 4b shows a flow chart illustrating a method of calculating the vehicle mass according to one embodiment of the invention.

Fig. 4c shows a flow chart illustrating a method of calculating the vehicle mass according to one embodiment of the invention.

Fig. 4d shows a flow chart illustrating a method of calculating the vehicle mass according to one embodiment of the invention.

Fig. 4e shows a flow chart illustrating a method of controlling the vehicle transmission according to one embodiment of the invention.

Fig. 5 shows a schematic representation of a computer device that is used according to one embodiment of the invention.

Detailed description of the drawings

Fig. 1 shows a schematic representation of a vehicle 1 and a control system for this according to one embodiment of the invention, in which 10 denotes an engine, for example a six-cylinder diesel engine, the crankshaft 20 of which is coupled to a single dry plate clutch, generally denoted by 30, which is enclosed in a clutch cover 40. Instead of a single-plate clutch, a two-plate clutch may be used. The crankshaft 20 is connected rotationally locked to the clutch housing 50 of the clutch 30, while the plate 60 thereof is connected and rotationally locked to an input shaft 70, which is rotatably supported in the housing 80 of a transmission generally denoted by 90. A main shaft and an intermediate shaft are rotatably supported in the housing 80. An output shaft 85 emerging from the transmission 90 is designed to drive the wheels of the vehicle.

Also shown are a first control unit 48 for controlling the engine 10 and a second control unit 45 for controlling the transmission 90. The first and second control units are designed for communication with one another via a lead 21. It will be described below how various processes and steps of the method are performed in the second control unit 45, but it should be apparent that the invention is not limited to this and that the first control unit 48, or a combination of the first and second control units may equally well be used. The second control unit 45 is designed for communication with the transmission 90 via a lead 24. The first control unit 48 is designed for communication with the engine 10 via a lead 26. The first and second control units can generally be described as control elements.

The vehicle 1 has a throttle lever 44 and a manual gear selector 46, which are designed for communication with the second control unit 45 via a lead 210 and 211 respectively. The gear shift selector 46 may have a position for manual gear shifting and a position for automatic gear changing of the vehicle. The throttle lever may be an accelerator pedal. A sensor 113 is designed to continuously measure the position of the throttle lever. The sensor 113 is designed for communication with the second control unit 45 via a lead 212. The position of the throttle lever implicitly indicates the quantity of fuel that is delivered to the engine combustion chamber. The quantity of fuel delivered indicates the engine torque. The second control unit 45 is therefore capable of continuously calculating a value representing the engine torque on the basis of a signal transmitted from the sensor 113.

Detector elements 111 are designed to detect, measure, estimate or register various conditions including those of the engine 10. The detector elements may be of various types. Examples of detector elements are the torque sensor Ilia and the engine power output sensor 111b. Fig. 1 shows only a detector element generally denoted by 111. The detector elements 111 are designed for communication with the first control unit 48^" via a lead 28.

There is also an acceleration sensor 114 designed to detect the acceleration a of the vehicle. The acceleration sensor 114 is designed to continuously detect the instantaneous acceleration a(i) of the vehicle and to communicate these values to the first control unit 48 via a lead 215. In the first control unit 48 a detected acceleration value a is matched to a time stamp R(i) . The term a(l) denotes the measured acceleration at the time (i) , the time being indicated by the time stamp R(i) . The time stamps R(i) are generated by the first control unit 48. Alternatively the measured acceleration a is furnished with a corresponding time stamp R(i) in the acceleration sensor 114, following which the acceleration value with time stamp a(i) is transmitted to the first control unit 48. According to one embodiment the acceleration sensor 114 is designed to continuously transmit signals representing the vehicle acceleration to the second control unit 45 via the first control unit 48.

According to one embodiment a torque sensor 110 is designed to measure the torque on the input shaft 70. The torque sensor 110 is designed to measure the torque that is produced by the engine 10 on the input shaft 70. The torque sensor 110 is designed for communication with the second control unit 45 via a lead 22. The torque sensor 110 is designed to continuously communicate an instantaneous value representing the torque on the input shaft to the second control unit 45. The value communicated representing the torque on the input shaft can be communicated in the form of an electrical signal to the second control unit. Alternatively the signal may be an optical signal. The signal may be analog or digital. The second control unit is designed to suitably convert the signal received, for example by means of an A/D converter (not shown in the figure) .

The torque sensor 110 may be designed to measure the torque on the output shaft 85. The torque sensor 110 is here designed to measure the torque that is produced by the engine 10 on the output shaft 85. It should be apparent that the torque sensor arranged in this way is designed to measure the torque within a wider torque range than in the case where the torque is measured on the input shaft.

When it is located on the input shaft 70, the torque sensor 110 may readily be used for other applications, such as clutch control, for example. Data received by the torque sensor are registered in the second control unit 45. Data received that are registered by the second control unit 45 are stored in a memory therein. According to one embodiment data measured by the torque sensor and subsequently stored in the memory in the second control unit 45 are torques with associated time stamps. According to one embodiment instantaneous torque values T(i) are measured every 100^th millisecond (0.1 s) and respective estimated values are stored with an associated time stamp R(i) . The time stamps R(i) are generated by the second control unit 45, where i is a whole number between 1 and N. N is a whole number, for example 1000. Table 1 below shows an example of four initial measurements for the first and lowest gear of the transmission during vehicle acceleration, for example when opening the throttle or in engine braking. Corresponding measurements can be performed for all transmission gears and stored in tables intended for this purpose in the second control unit 45.

Table 1, Measured torque T(i) with respective time stamps R(i) .

According to one embodiment the torque sensor 110 is designed to continuously transmit signals representing the torque to the second control unit 45.

Since the transmission ratio and efficiency are known, the engine torque on the output shaft 85 can be continuously calculated. Since the torque on the output shaft is different for the different gears engaged, the calculations take account of this.

According to one embodiment data representing calculated values for the torque on the output shaft 85 are stored together with associated time stamps in the memory in the second control unit 45. The engine torque can be calculated from the quantity of fuel injected into the engine combustion chamber. Account is also taken of any auxiliary unit fitted, in order to obtain accurate estimates of the torque. The calculation may be performed in the second control unit 45.

An inclination sensor 115 is provided on the transmission 90. According to one embodiment the inclination sensor 115 is arranged in the transmission 90. The inclination sensor 115 is designed to measure the gradient of the present running surface of the vehicle 1. The running surface is sometimes a road, the gradient of which is measured. The inclination sensor 115 may be of the piezoelectric type. The inclination sensor 115 is designed for communication with the second control unit 45 via a lead 23. According to one embodiment the inclination sensor 115 is designed to continuously transmit signals representing the running surface gradient to the second control unit 45.

According to another embodiment signals representing- the running surface gradient are transmitted to the second control unit at certain intervals, for example intervals of 0.01 seconds or intervals of 0.5 seconds.

According to one embodiment signals representing the running surface gradient, the engine torque, the vehicle acceleration and the vehicle speed are continuously transmitted to the second control unit 45, where they are stored in an array together with respective time stamps. The array is stored in the second control unit 45. The array is also referred to as a table. Fig. 3c below describes such a table.

According to one embodiment values S(i) representing the running surface gradient are measured by means of the inclination sensor 115 every 100^th millisecond (0.1 s) and each measured value is stored with a respective corresponding time stamp R(i) . The time stamps R(i) are generated by the second control unit 45, i being a whole number. Table 2 below shows an example of four initial measurements for the first and lowest gear of the transmission. Corresponding measurements can be performed for all transmission gears and stored in maps intended for this purpose in the second control unit. It should be noted that the time stamps are the same as described above with reference to Table 1. S(I), T(I) and a(i) are therefore measured basically simultaneously and form a first data group (i=l) measured after 0.1 seconds (R(I) . S (2), T (2) and a(i) are measured basically simultaneously and form a second data group (i=2) measured after 0.2 seconds (R(2) ) . Respective measured gradients are not explicitly stated in Table 2.

Table 2, Measured gradient of the vehicle running surface S(i) with respective time stamp R(i) .

In a similar way to the torque T(i) and the gradient of the vehicle running surface S(i) the vehicle acceleration is measured and registered by the acceleration sensor 114 and is provided with corresponding time stamps R(i) . The vehicle acceleration is stored in a Table 3, as shown below.

Table 3, Measured vehicle acceleration a(i) with respective time stamp R(i) .

Similarly a speed sensor 116, which is designed for communication with the first control unit 48 via a lead 216 detects the speed of the vehicle and communicates this value in the form of a signal. The vehicle speed is stored in a Table 4 as shown below:

Table 4, Measured vehicle speed V(i) with respective time stamp R(i) .

According to one embodiment the vehicle acceleration is calculated on the basis of the vehicle speed. This therefore allows just one sensor rather than two to be used in order to obtain the vehicle acceleration and the vehicle speed.

It is commonly known that

F_D~-F_R-ma (D

where F_D is the total motive force of the vehicle, which according to one embodiment of the invention is estimated according to Equation 2 below.

F_D- TXJBt] R (2)

F_R is furthermore the total resistance force which according to one embodiment of the invention is estimated according to Equation 3 below F_R~mgsin(α)+k_λm+k₂V² (3)

where ki is a rolling resistance constant; k₂ is an air resistance constant; g is the acceleration due to gravity; V is the vehicle speed;

B is the transmission ratio on the vehicle rear axle; U is the transmission ratio in the vehicle transmission T is the engine torque; a is the gradient of the vehicle running surface; T) is the efficiency on the vehicle drivetrain; and JR is the wheel radius.

An alternative term for a is S. S(i) is therefore a term for an a which is related to a certain time stamp R(i) .

(l) + (2) + (3) gives

—~--(mgshx(a)+k_lm-i'k₂V²)~ma (4) R

At least two cases can be distinguished:

Case 1

Assuming that the vehicle speed is negligible, that is to say V s O, or that V is less than a certain given limit, for example 5 km/h, and a value equal to zero is therefore assigned, an estimate of the vehicle mass m is then given by Equation 5 below: TUBη m R (5) gsin(α)+ &_j +β

Case 2

Assuming that the vehicle speed is not negligible, that is to say W=O, or at least greater than a certain given limit, for example 5 km/h, an estimate of the vehicle mass m is then given by Equation 6 below:

gsϊn{a)+k_x -¥a

It should be apparent that the values of ki, k_∑, B and τ_\, for example, may vary in driving but they will not be described further in this description. One or more of k_lr k₂, g, B, U and rj may be stored in the second control unit as constants to be used in calculating the vehicle mass m according to the above. According to one embodiment a set of values exists for each parameter. There may be five different values for the air resistance constant k_∑ depending, for example, on whether or not a trailer is coupled to the vehicle 1. Furthermore, there may be, for example, five different values for the acceleration due to gravity gi-gsr of which an optimum value, for example g₃, can be selected for use in calculations of the mass. Alternatively one or more of k_lr k_∑, g, B₁ U and η may be detected and fed to the second control unit 45 for use in calculations of the vehicle mass m according to the above. The efficiency of the vehicle drivetrain rj may vary whilst the vehicle is being driven. The efficiency may vary, for example, between 0.97 and 0.99. The efficiency is typically different for different gears. The wheel radius is typically a constant, which is stored in the second control unit 45.

According to one embodiment of the present invention the Equation (5) can also be expressed as:

T(i)UBη

According to one embodiment of the present invention the Equation (6) can also be expressed as:

Fig. 2 shows the lead 28 and examples of running data detected, measured, estimated or registered by the detector elements 111. Examples of running data are the engine torque 201, the crankshaft torque 202, the engine power output 203, the external wind conditions 204, the exhaust gas back-pressure 205 and the fuel consumption 206.

Other running data used are the vehicle speed V, the transmission gear ratio U, the road, gradient a and the drivetrain efficiency η. According to the invention the acceleration due to gravity g, the rolling resistance constant kx and the air resistance constant k.₂ are also used in order to calculate the vehicle mass according to the above.

In Fig. 3a a dashed line B illustrates a cross section of a horizontal plane. A solid line A illustrates a cross section of a level running surface which has a gradient a radians relative to the horizontal plane B. The solid line A may typically represent a cross section of a level road on which the vehicle 1 is being driven. In Figs. 3a and 3b it is assumed that the direction of travel of the vehicle is from left to right. The level running surface A in Fig. 3a therefore represents an uphill slope for the vehicle.

In Fig. 3b a dashed line B correspondingly illustrates a cross section of a horizontal plane. A solid line A illustrates a cross section of a level running surface which has a gradient a radians relative to the horizontal plane B. On the same assumption as in Fig. 3a, the level running surface therefore represents a downhill slope for the vehicle. It should be apparent that the gradient a here is minus (-) a radians relative to the horizontal plane B.

Fig. 3c illustrates a Table Gl with data entered according to one embodiment of the invention.

The table shown in Fig. 3c contains measured and calculated values for a first gear Gl. According to one embodiment of the invention corresponding tables exist for all gears of the vehicle. According to one embodiment in which the transmission has 12 different gears, therefore, a table exists for each of the 12 gears of the transmission. Data in the various tables are stored as described above. The various tables are designated Gl to G12 for the respective gear. The table illustrated in Fig. 3c contains N rows. N is a whole number. N may be equal to 50, for example.

Instantaneous detected values T(i), a(i), S(i) and V(i) are stored in the table over the measured data values for the first gear of the vehicle. For each set of data values (of the same (i) ) a respective value m(i) is calculated representing either the vehicle mass calculated by Equation 7 or 8 depending on the speed V of the vehicle. It should be noted that there may be more Gl tables, just as there may be more G2 tables etc. For each gear for which an estimate of the vehicle mass according to the present invention is performed, a new table can be created for a given transmission ratio on the vehicle drivetrain. According to one embodiment a table contains a series of measurements. According to another embodiment a table contains multiple series of measurements. The term series of measurements relates to measured values measured and calculated in succession for a specific transmission ratio for a basically constant actual vehicle mass M.

The vehicle masses m(l)-m(N) calculated should have a relatively small standard deviation, provided that they relate to the same series of measurements.

Below are two examples which illustrate how the vehicle mass can be calculated.

Example 1

According to this example m(l), m(2) and m(3) illustrated in Fig. 3c are used. That is to say the first three calculated vehicle masses for the lowest gear of the transmission are used.

A mean value m is calculated in the second control unit 45, where

Example 2

According to this example the first three calculated vehicle masses for the lowest gear of the transmission (from table Gl) are used, together with three sequentially calculated values for the other vehicle gears, that is m(7), m(8) and m(9), which are stored in the table G2.

A mean value m is calculated in the second control unit 45, where

According to this example parts of series of measurements for different transmission ratios (various tables G1-G12) are used to calculate a mean value m fox assessment of the actual vehicle mass M. It should be noted that the actual vehicle mass M is basically the same for the two partial series.

Fig. 4a shows a flow chart illustrating a method of calculating the mass of an engine-driven vehicle according to one embodiment of the invention. In a first step s401 of the method the following secondary steps are performed:

- receiving of a first signal containing information on the gradient of the vehicle running surface;

- receiving of a second signal containing information on the torque; - receiving of a third signal containing information on the vehicle acceleration; and

- calculation of the vehicle mass as a function of the first, second and third signals; - controlling of the vehicle transmission as a function of the vehicle mass calculated. According to one embodiment of the invention the vehicle mass is calculated prior to a first gearshift after starting.

According to one embodiment a fourth signal is received containing information on the vehicle speed and the vehicle mass is calculated as a function of the fourth signal.

Fig. 4b shows a flow chart illustrating a method of calculating the vehicle mass according to one embodiment of the invention. A first step s404 of the method serves to detect which transmission ratio is present on the vehicle transmission.

A subsequent step s406 of the method serves to determine whether a table already exists for the gear detected. If this is the case, a step s450 ensues with reference to Fig. 4c. If no ready-created table exists, a step s408 of the method ensues.

Step 408 serves to create a table intended for storing measured data, such as detected torque T(i) and the running surface gradient S(i), the vehicle acceleration a(i) and the vehicle speed V(i) . The table is intended to store measured or processed data in respect of a specific transmission ratio of the vehicle drivetrain, that is to say the transmission ratio detected in step s404. The detected transmission ratio in this example is the lowest gear of the transmission, also referred to as a first gear. According to this example a created table is that shown with reference to Fig. 3c, that is to say Gl. The table is created and stored in a memory in the second control unit 45. The table (6xN, where N=IO) is empty after it has been created. The table is dynamic, that is to say more rows can be created following which more measured data are stored. Further rows in the table can be created automatically by the control unit as received data are registered. Step s412 of the method serves to register a value for the measured torque T(i), as a representation of the engine torque. The vehicle acceleration a(i), the gradient of the running surface, which in this case is a road gradient a, denoted by S(i) and the vehicle speed V(i) are furthermore registered. Registered values according to this step of the method have the same time stamp R(i) . If, for example, R(i) is R(I), T(I), a(l) etc. are stored on one row of the table. Step s412 of the method is followed by step s416.

Step s41β of the method serves for receiving the variables and constants, which in addition to the data that have been registered according to the preceding step s412 of the method enter into the calculation of the vehicle mass with reference to Equation 7 or 8, that is to say k_lr k₂, g, B, U, R and rj. Step s41β of the method is followed by step s418.

Step s418 of the method serves to calculate the vehicle mass m(i) according to Equation 7 or 8 using T(i), S(i), a(i) and V(i) and adequate values of ki, k_∑, g, B, U, R and r_/. According to one embodiment the vehicle mass is calculated according to both Equation 7 and Equation 8. Step s418 of the method is followed by step s420.

Step s420 of the method serves to store the result m(i) of the calculation performed in s418 in a memory in the second control unit 45. Step s420 of the method is followed by step s424.

Step s424 of the method serves to determine whether an aforementioned process must be repeated, that is to say whether a new row containing new T(i), S(i), a(i) and V(i) for a subsequent time (i+1) must be entered into the table. If this is the case, step s412 of the method ensues. If not, the method is concluded. A program stored in the second control unit 45 controls the decision-making process according to these criteria.

A decision is furthermore taken as to whether stored information is to be deleted from the table. If so, the information is deleted.

Fig. 4c shows a flow chart illustrating a method of calculating the vehicle mass according to one embodiment of the invention. Step s450 of the method serves to select an already created table corresponding to the relevant transmission ratio on the vehicle drivetrain. The table selected may be Gl, for example, which corresponds to the lowest gear of the vehicle, that is to say the first gear of the vehicle. Step s450 of the method is followed by a step s453.

Step s453 of the method serves for receiving T(i), S(i), a(i) and V(i) . Step s453 of the method is followed by a step s456.

Step s456 of the method serves for receiving k_lr k₂, g, B₁ U, R and T). Step s45β of the method is followed by a step s457.

Step s457 of the method serves to calculate the vehicle mass m(i) according to Equation 7 or 8 using data received in s453 and s456. Step s457 of the method is followed by a step s459.

Step s459 of the method serves to store the result m(i) from step s457 in a memory in the second control unit 45. Step s459 of the method is followed by a step s462.

Step s462 of the method serves to decide whether an aforementioned process must be repeated, that is to say whether a new row containing new T(i), S(i), a(i) and V(i) for a subsequent time (i+1) must be entered into the table. If this is the case, step s450 of the method ensues. If not, the method is concluded. A program stored in the second control unit 45 controls the decision-making process according to these criteria.

Step s480 of the method serves to select one or more tables G1-G12. Step s480 of the method is followed by a step s483.

Step s483 of the method serves to select a number of calculated vehicle masses m(i) from respective selected tables G1-G12. The vehicle masses selected are all calculated under basically the same load conditions, that is to say the actual vehicle mass M is basically the same. However, the various calculated vehicle masses m(i) may accordingly be calculated for different transmission ratios on the vehicle drivetrain and may thereby be stored in different tables. Step s483 of the method is followed by a step s485.

Step s485 of the method serves to calculate the mean value from the calculated vehicle masses selected, in order to obtain a good approximation m of the actual vehicle mass M. Step s485 of the method is followed by a step s488.

Step s488 of the method serves to store m in the second control unit for use as a basis for a gear selection strategy stored therein. After step s488 the method is concluded.

Fig. ,4e shows a flow chart illustrating a method of controlling the vehicle transmission according to one embodiment of the invention in which steps s480 up to and including s485 of the method are the same as described with reference to Fig. 4d. Step s485 of the method is followed by a step 499.

Step s499 of the method serves to control the vehicle transmission as a function of the calculated value m representing the actual mass M of the vehicle without first having been stored in a table. This represents an even faster way of implementing a good estimate of the vehicle mass as control information. After step s499 the method is concluded.

Fig. 5 shows an apparatus 500, according to one aspect of the invention, comprising a non-volatile memory 520, a data processing unit 510 comprising a processor, and a read/write memory 560. The memory 520 has a first memory part 530, in which a computer program for controlling the apparatus 500 is stored. The computer program in the memory part 530 for controlling the apparatus 500 may be an operating system.

The apparatus 500 may be incorporated into a control unit, for example, such as the control unit 45 or 48. According to a preferred embodiment an apparatus 500 is incorporated into both the first control unit 48 and the second control unit 45. The data processing unit 510 may comprise a microcomputer, for example.

The memory 520 also has a second memory part 540, in which a program is stored containing methods with reference to Figs. 4a-4e. In an alternative embodiment the program is stored on a separate, non-volatile data storage medium 550, such as a CD, for example, or a replaceable semiconductor memory. The program may be stored in an executable form or in a compressed state.

Where the data processing unit 510 is described below as running a special function, it should be clearly understood that the data processing unit 510 runs a special part of the program that is stored in the memory 540 or a special part of the program that is stored on the non-volatile recording medium 550.

The data processing unit 510 is adapted for communication with the memory 550 via a data bus 514. The data processing unit 510 is also adapted for communication with the memory 520 via a data bus 512. The data processing unit 510 is furthermore adapted for communication with the memory 560 via a data bus 511. The data processing unit 510 is also adapted for communication with a data port 590 via a data bus 515.

The methods described in Figs. 4a-4e can be performed by the data processing unit 510 in that the data processing unit 510 runs the program which is stored in the memory 540 or the program which is stored on the non-volatile recording medium 550.

Also stored in the second memory part 540 is a computer program comprising computer code for performing the steps of. the method according to the flow chart, with reference to any of Figs. 4a-4e, when said computer program is executed on a computer.

For application of the invention, a computer program product comprising program code is stored on a machine- readable medium for performing the steps of the method according to the flow chart, with reference to any of Figs. 4a-4e, where said computer program is executed on the computer.

For application of the invention, a computer program product can be loaded directly into an internal memory of a computer, comprising program code for performing the steps of the method according to the flow chart, with reference to any of Figs. 4a-4e, where said computer program product is executed on the computer.

Claims

JS, case 14896WO, 2005-06-07 Patent claims

1. An engine-driven vehicle comprising at least one engine (10) , and control elements (45; 48) designed to control a transmission (90) that can be driven by the engine, the control elements being designed to receive a first signal transmitted from a first sensor (115) and containing information on the gradient of the vehicle running surface, and to receive a second signal transmitted from a second sensor (110; 113) and containing information on the torque, and to receive a third signal transmitted from a third sensor (114) and containing information on the vehicle acceleration, characterized in that the control elements are further designed to calculate the mass (m(i); Jn ) as a function of the first, second and third signals, and to control the transmission as a function of the vehicle mass calculated.

2. The engine-driven vehicle as claimed in claim 1, characterized in that the second sensor is a torque sensor (110) , which is designed to measure a torque on the transmission input shaft and/or a torque on the transmission output shaft and/or an engine torque.

3. The engine-driven vehicle as claimed in claim 1, characterized in that the second sensor is a sensor (113) which is designed to measure a throttle lever position and hence information on a quantity of fuel delivered to the engine representing the engine torque.

4. The engine-driven vehicle as claimed in any one of claims 1 to 3, characterized in that the vehicle mass is also calculated as a function of the vehicle speed.

5. A method of calculating the mass of an engine- driven vehicle, the method comprising the following steps:

- receiving of a second signal containing information on the torque;

- receiving of a third signal containing information on the vehicle acceleration; characterized by the following steps

- calculation of the vehicle mass as a function of the first, second and third signals; and

- controlling of the vehicle transmission as a function of the vehicle mass calculated..

6. The method as claimed in claim 5, characterized by the step of calculating the vehicle mass as a function of the second signal containing information on a torque on the transmission input shaft and/or a torque on the transmission output shaft and/or the vehicle engine torque.

7. The method as claimed in claim 5, characterized by the following step - calculation of the vehicle mass as a function of the second signal containing information on a quantity of fuel delivered to the engine representing the engine torque.

8. The method as claimed in any one of claims 5 to

7, characterized by

- calculation of the vehicle mass prior to a first gear shift after starting.

9. The method as claimed in any one of claims 5 to

8, characterized by the following step

- receiving of a fourth signal containing information on the vehicle speed and calculation of the vehicle mass as a function of the fourth signal.

10. A computer program product comprising program code for performing the steps of the method in claim 5, when said computer program is executed on a computer.

11. A computer program product comprising program code stored on a machine-readable medium for performing the steps of the method in claim 5, when said computer program is executed on the computer.