IT202100029984A1 - A METHOD AND EQUIPMENT FOR CHECKING AN ELECTRIC HYBRID ARCHITECTURE OF A VEHICLE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?A METHOD AND EQUIPMENT TO CONTROL AN ELECTRIC HYBRID ARCHITECTURE OF A VEHICLE?

TECHNICAL FIELD

The invention? relating to a method and apparatus for controlling an electric hybrid architecture of a vehicle, in particular an off-road vehicle such as an agricultural vehicle.

BACKGROUND OF THE INVENTION

Transmissions for off-road vehicles such as agricultural vehicles can be equipped with different configurations, such as:

? manual gearbox transmissions, in which all transmission gears are engaged directly by the driver through lever mechanisms that control clutches, synchronizers and dog clutches to select the gear;

? semi-automatic gearbox transmission, in which some gears are engaged in mode? with automatic transmission, i.e. switching torque using a pair of clutches, and other gears are driven as in manual transmissions; And

? fully automatic transmission, in which all transmission gears are engaged in mode? with automatic transmission.

For semi-automatic and fully automatic transmissions, a dual clutch architecture (DCT) is available. often considered an optimal configuration in terms of efficiency and comfort? of the driver.

Referring to figure 1, a DCT architecture with semi-automatic gearbox? positioned between the engine and the axle drive shaft and includes a motorized slider module, an automatic shifting gear module, a non-automatic shifting gear module and, optionally, a sliding module.

Usually the automatic transmission gear module includes two main clutches, namely a forward clutch and a reverse clutch to select forward or reverse movement, and two additional clutches, namely an odd clutch and an even clutch. to select one of two different subsets of gears, namely the odd and even gears.

More? in detail, the gear sequence ? distributed according to a logic of even gears operated by the even clutch and odd gears operated by the odd clutch. Therefore, the odd clutch and even clutch are switched alternately during a gear shift sequence.

Is the even or odd gear engaged? connected to an intermediate shaft at the range stage usually comprising at least one pair of gear sets which can? be engaged between the intermediate shaft and the axle drive shaft.

Such a pair of gear sets is selected thanks to the dog clutches when they briefly disengage the mechanical path via the aforementioned clutches of the automatic transmission gear module. In this way the transmission is not coupled to the engine and can? gear change be performed in the range module.

However, as noted above, shifting involves a loss of torque for a predetermined time. This loss of torque in the transmission clearly leads to a deceleration of the vehicle which can be dangerous.

Furthermore, the deceleration, with the subsequent acceleration due to clutch engagement when the range change is performed, provides a jolt that reduces comfort. of the driver.

Consequently, there is a need of an improvement in the field of vehicle transmissions, in particular by addressing the aforementioned disadvantages.

A purpose of the invention? satisfy this need? in an economical and optimized way.

SUMMARY OF THE INVENTION

The aforementioned object is achieved by means of a method and an apparatus as claimed in the attached set of claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, in the following ? described a preferred embodiment, by way of non-limiting example, with reference to the attached drawings, in which:

? figure 1? a schematic representation of a transmission for an off-road vehicle;

? figure 2? the schematic representation of figure 1 with pi? details on one of its range modules;

? figure 3? a schematic representation of an exemplary hybrid architecture that is controllable by the method and apparatus of the invention; And

? figure 4 shows diagrams of the variation of the different quantities? of the elements of the hybrid architecture over time during the control performed according to the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 describes a general arrangement of the mechanical portion 1? of a 1 hybrid drivetrain for an off-road vehicle (not shown) which ? interposed between an engine 2 of the vehicle and an output shaft 3, such as an axle drive shaft.

As shown and in itself? known, engine 2? advantageously connected to an input shaft 4 of the transmission 1 via a damper 5 placed between an output shaft 6 of the engine 2 and the input shaft 4 of the transmission 1. The input shaft 4 passes through the transmission to be used by other elements of the vehicle, such as a power take-off module (not shown) and to provide torque to the output shaft 3 via transmission 1.

The transmission 1 comprises, in series with respect to each other, a motorized slider module 1<I>, a gear change module 1<II>, a range change module 1<III>. Furthermore, transmission 1 can? include an optional 1<IV> slide module.

Referring to figure 2, non-limiting examples of the gear change module and the range change module 1<II>, 1<III> are described in detail below.

The gear shift module 1<II >? made as an automatic gearbox, i.e. it includes a first clutch 10, hereinafter ?even clutch?, and a second clutch 11, hereinafter ?odd clutch?. The clutch equal 10? configured to couple a first auxiliary shaft 12, hereinafter "even shaft", to the input shaft 4, preferably via the set of gears 13. The odd clutch 11 is configured to couple a second auxiliary shaft 14, hereinafter ?odd shaft?, to the input shaft 4, preferably via the gear set 13. The gear set 13 can? comprise a pair of gear wheels rigidly supported by the input shaft 4.

Although if not shown, as is known, the motorized slider module 1<I>includes clutches to manage the torque on the gear shift module 1<II>according to the clockwise or counterclockwise direction of rotation of the input shaft 4 of the gear shift module gear 1<II>, when torque is transmitted.

The clutches 10, 11 are operated by the respective actuator, as per se? known. The even tree 12 and the odd tree 14 each include a plurality? of selection elements, for example tooth clutches or joints 16, supported in a fixed way in rotation by the respective shaft 12, 14 and therefore rotate together with the latter.

Preferably the even tree and the odd tree 12, 14 receive a plurality? of gears having a size or number of teeth different from each other and which are supported in a freely rotatable manner by the respective shaft 12, 14, for example by means of bearings, so that they are not forced to rotate at the same speed? of the respective shaft 12, 14 when the engagement tooth coupling 16 is in its neutral position.

As an example, the even tree 12 can? comprise two gears 17, i.e. a first gear 17<I>having the largest diameter large and a second gear 17<II>having the largest diameter? small.

Similarly, the odd tree 14 can? comprise two gears 18, i.e. a first gear 18<I>having the largest diameter large and a second gear 18<II>having the largest diameter? small.

The gears of the gears 17, 18, when selected, represent the different speed ratios? of transmission; that is, four transmission ratios with corresponding counter-wheels fixedly supported by an intermediate shaft 19.

As mentioned above, the gears of the gears 16, 18 can be selected by means of a toothed clutch 16 configured to couple the shaft to the chosen gear when it is operated to move along the longitudinal axis of the shaft.

The aforementioned intermediate shaft 19 can be supported concentric on the input shaft 4 which passes through the transmission to supply torque to other operating elements of the work vehicle or in an additional position that does not interfere with the input shaft. The intermediate shaft 19 ? connected to the output shaft 3 or to a shaft passing through the gear module 1<IV>if present, via a gear range module 1<III>.

The gear range module 1<III >? configured to couple the intermediate shaft 16 to the output shaft 3/slide shaft choosing from a plurality? of gear ratios which are multiplied by the DCT gear ratios described above.

As an example, the gear range module 1<III>can? include a first gear 21<I >called ?low? gamma and a second gear 21<II >called a "speed" gamma? having different dimensions and configured to be selectively coupled to the output shaft 3/slide shaft via the respective dog clutches 16. In this way, the transmission 1 of the provided exemplary embodiment provides eight possible gear ratios, for via the four DCT ratios repeated on the two range ratios.

In detail, the first gear 21<I>and the second gear 21<II>are supported in a free rotary manner on the intermediate shaft 19 and are a toothed coupling 16 is provided which selectively couples the latter to the intermediate shaft 19.

The gears 21, when selected, represent the different speed ratios? of the transmission range made with corresponding counter-wheels fixedly supported by the output shaft 3/slide shaft.

In figure 3? electrical portion 1?? shown of the hybrid transmission 1.

The hybrid transmission 1 includes a generator 25, an electric motor 26 and an electric energy storage system, hereinafter called ?accumulator means? 27 which are electrically connected between each other via electrical power management means 28.

In detail, the generator 25? configured to mechanically engage with the input shaft 4, preferably via a set of gears 29 made between the input shaft 4 and the input shaft 25? of the generator 25 upstream of the mechanical portion 1?? of the transmission or between the slider module 1<I >and the damper 5. As is known, the generator 25 is configured to transform the mechanical torque provided by the input shaft 4 into electrical energy.

This electrical energy can be stored in accumulator means 27 configured to store the electrical energy supplied by the generator 25 or to supply energy to the electric motor 26.

The electric motor 26 ? operationally connected to the output shaft 3 downstream of the range change module 1<III>(or, if present, downstream of the sliding module 1<IV>).

In particular, the electric motor 26 includes an output shaft 26? That ? connected to the output shaft 26? via a gear transmission 30 configured to allow at least one gear ratio between the output shaft 26? and the output shaft 3.

The electrical power management means 28 preferably comprise a unit power distribution, PDU, 28? electrically connected to the accumulator means 27, to the generator 25 and to the electric motor 26 to manage the transfer of electrical energy between them. Preferably, the connection of the unit? power distribution 28? ? made using inverter 28?? which are interposed with the latter and, respectively, the generator 25 and the electric motor 26.

Preferably, the hybrid transmission 1 can? furthermore comprising braking resistor means 31 electrically connected to the electrical power management means 28, in particular via the PDU 28?.

The DCT 1 also includes a?unit? electronic control system, 32 configured to be electrically connected to the aforementioned actuators of the clutches 10, 11 and to the dog clutches 16, to the engine 2, to the generator 26 and to the electric motor 25 and comprising processing means suitable for controlling their operations.

The unit? electronic control 32 can? be either the vehicle ECU or the driveline ECU. The unit? electronic control 32 ? configured to control the aforementioned elements of transmission 1 automatically following the gear control logic employed in a specific software code, which can? be downloaded to the unit? electronics and configured to perform the control method as described below.

The operation of the hybrid transmission 1 described above? the following.

During a standard vehicle driving condition, assuming the first gear ratio and the low range gear ratio are engaged, engine 2 supplies torque to input shaft 4 which passes through clutch number 10 to shaft number 12 and through the gear set 14<I>to the intermediate shaft 19 and then through the gear set 21<I>to the output shaft 3. Assuming that the user wants to switch to the speed range ratio, that is, engaging the set of gears 22<II>, starting from the above condition, then the unit? electronic control controller? the elements of transmission 1 as follows.

In a first phase, the clutch 10 is immediately disengaged and the electric motor 26? checked to provide the torque that ? was transmitted by the clutch equal to 10 to the output shaft 3.

Then, in a second phase, the electric motor 26 increases, in a regular manner, with an appropriate control strategy, for example linearly, the torque supplied to the output shaft 3 until is the torque value reached which will be? provided by the speed range ratio, if engaged. If not ? If sufficient energy is present in the accumulator means 28 or have the default option of not discharging the latter, the motor 2 increases its speed. to allow the generator 25 to provide energy to the electric motor 25 to carry out its function.

Once this speed? is reached by the electric motor 26, then the tooth clutch 16 is controlled to disengage the first range gear 21<I>and engage the second range gear 21<II>.

Then, in a third phase, the electric motor 26 decreases its speed. while the clutch equals 11? engaged in a regular way, for example through a linear inclination, thus passing? again to a mechanical transmission of all the torque from the motor 2 to the output shaft 3. In this condition the electric motor 26 is controlled according to the law of control of clutch engagement to maintain the vehicle at speed? constant until? a new acceleration request is made by the driver.

This functioning? schematized in the graphs shown in figure 4, which highlights:

i) the first phase between time 14 s and 14.5 s in which the clutch? totally disengaged and the couple? supplied by the electric motor 26. In this case ? is the torque value switching provided by the mechanical portion 1 evident? and from the electrical portion 1?? of the hybrid transmission;

ii) the second phase between the time 14.5 and 16.5 s in which the electric motor 26 increases its speed? until? reaches the speed? corresponding to the new range ratio to be selected via selection means which pass from the first range transmission ratio to the second range transmission ratio; And

iii) the third phase between 16.5 s and 17 s in which the clutch? engaged in a regular manner and the electric motor 25 decreases in a regular manner, according to the clutch engagement, to provide torque to the output shaft.

According to the above operation, the present invention is relating to a method for controlling range shifting in a semi-automatic hybrid transmission 1 as described above and comprising the following steps:

i) receiving a gear change request from a first range gear ratio to a second range gear ratio;

ii) instantly disengage the clutch which transmits the torque towards the output shaft and supply all the torque which previously passed through this clutch to the output shaft via the electric motor 26;

iii) change the speed? supplied by the electric motor to reach a speed? objective what? the speed? which is determined by engaging the second range transmission ratio;

iv) when is this speed reached? objective, control the selection elements to disengage the first range gear ratio and engage the second range gear ratio and begin to engage the clutch and decrease the torque provided by the electric motor 26 until all torque supplied to the output shaft is supplied through the clutch.

In particular, the method can furthermore include, in parallel with phase ii) the control of the engine 2 to bring the generator 25 to supply enough electrical energy to the engine 26.

Preferably, the engagement of the clutch and the decrease in torque of the electric motor in phase iv) are controlled to keep the speed constant. of the vehicle.

As mentioned above, the method can? be performed by the unit? control 32 by means of control logic in the form of software code downloaded to the unit? control. This code includes instructions that determine whether the unit executes the method. control 32, when the code is executed by the unit? control 32. The code can? be stored on a computer-readable device.

In light of the foregoing, the advantages of a hybrid transmission equipped with an apparatus configured to carry out the method according to the present invention are evident.

Thanks to the proposed method, ? It is possible to change range gear without providing shocks that are uncomfortable for the driver and possibly dangerous.

In fact, even if the hybrid transmission is ? a semi-automatic transmission, there is? a continuous torque transmission at the output shaft as in a fully automatic transmission. Consequently, for this reason the speed? of the vehicle does not have sudden variations but, rather, the speed? of the vehicle varies on a regular basis.

Furthermore, the proposed system can? be used in a fully autonomous vehicle that is controlled by the unit? electronics 30. Furthermore, the automatic range gear ratio change is performed in a very short period of time, for example 3 seconds.

? It is clear that modifications can be made to the method and apparatus described which do not go beyond the scope of protection defined by the claims.

For example, the provided gear ratio module and the range gear ratio module may comprise a different number of gear wheels.

Additionally, additional shafts or clutches may be present. Clearly, the cursor module or the scroll module can? be accomplished in different known ways.

Claims (6)

1. A method for controlling a hybrid transmission (1) of a work vehicle, the hybrid transmission (1) comprising a mechanical portion (1?) equipped with: - an input shaft (4) configured to be coupled to an internal combustion engine (2) of said vehicle to receive power from the same, - an output shaft (3) connected to at least one drive axle of said vehicle, - a gear ratio module (1<I>) and a range gear ratio module (1<II>) operationally interposed in series with each other between said input and output shafts (3, 4) via an intermediate shaft (19) said transmission ratio module (1<I>) comprising a first and a second shaft (12, 14) each configured to support a plurality? of gears (17, 18), said first and said second shafts (12, 14) being configured to be coupled, via respective clutches (10, 11), to said input shaft (2) and being configured to be coupled to said intermediate shaft (19) defining with one of said gears (17, 18) a speed ratio? predetermined between said input shaft (2) and said intermediate shaft (19), said gamma transmission ratio module (1<II>) comprising a plurality? of range gears (21<I>, 21<II>) supported by said intermediate shaft (19) and configured to engage a shaft operatively connected to said output shaft (3) - a plurality? of selection elements (16) configured to slide on the support shaft (12, 14, 19) to select said wheels (17, 18, 21), the hybrid transmission (1) including an electronic portion (1??) equipped with: - a generator (25) operationally connected to said input shaft (4) to receive the torque transmitted by the latter and transform this torque into electrical energy; And - an electric motor (26) operatively connected to said output shaft (3) downstream of said range gear module (1<II>) and configured to impart torque to the output shaft (3); said method comprising the following steps: i) receiving a gear change request from a first range transmission ratio (21<I>, 21<II>) to a second range transmission ratio (21<I>, 21 <II>); ii) instantly disengage the clutch (10, 11) which transmits the torque towards the output shaft (3) and supply all the torque that previously passed through this clutch to the output shaft (3) via said electric motor (26) ; iii) change the speed? supplied by said electric motor (26) to reach a speed? objective what? the speed? to be transmitted by engaging said second range transmission ratio; iv) when is this speed reached? objective, control the selection elements (16) to disengage the first range transmission ratio and engage the second range transmission ratio and begin to engage the disengaged clutch (10, 11) and decrease the torque provided by said electric motor ( 26) until? all the torque supplied to the output shaft (3) is supplied again through said clutch (10, 11). 2. The method according to claim 1, further comprising, in parallel with step ii) controlling said motor (2) to cause said generator (25) to provide sufficient electrical energy to said motor (26). 3. Method according to claim 1 or 2, wherein the engagement of the clutch and the decrease in torque of the electric motor in phase iv) are controlled to keep the speed constant. of the vehicle. 4. Apparatus for controlling a hybrid transmission (1) of a work vehicle, the apparatus comprising a unit? electronic control device (32) programmed to implement the method according to any of the previous claims. 5. Software code comprising instructions that, when the program is executed by said unit? electronic control (32) of the appliance according to claim 4, does s? that the unit? electronic control device (32) carries out the method according to any one of claims 1 to 3. 6. Computer-readable media on which ? stored the software code of claim 5.