RU2462634C2 - Method and device of automatic or semiautomatic gear selection for breakaway - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: low gear is thrown in for breakaway, traction torque is controlled to define if low gear is too high for first breakaway at current conditions. In case low gear is too high, first breakaway is interrupted to automatically brake the vehicle. Low gear is disengaged to select and throw in adapted second for breakaway and to control traction torque. Breakaway second featured higher gear ratio compared with low gear. Second attempt of breakaway is made. In case sufficient torque is transmitted to driving wheels, braking is terminated. Proposed vehicle comprises power plant, step-by-step automatic transmission, driving wheels, brake and control unit. Said control unit allows effecting said stages.

EFFECT: reliable breakaway.

8 cl, 4 dwg

Description

Technical field

The invention relates to a method for automatic or semi-automatic selection of the optimal gear for starting off the vehicle according to the preamble of claim 1 of the claims.

The invention also relates to a vehicle having a control unit capable of providing steps for automatically or semi-automatically selecting the optimal gear for starting according to the preamble of claim 7.

The invention also relates to a computer program and computer program products for implementing the aforementioned method.

State of the art

Heavy-duty vehicles are increasingly equipped with automatic transmissions such as automatic mechanical transmissions (AMT), which became possible with the development of microcomputer technology, which allowed using the control computer and several controls, for example, servomotors, to precisely control the engine speed, turn on and turning off the automatic disk clutch of the engine and gearbox and clutch elements of the gearbox relative to each other and thereby m always ensure smooth shifting to the gear with the correct speed.

An AMT gearbox typically has an input shaft, an intermediate shaft with at least one gear engaged with a gear on the input shaft, and a secondary shaft with gears that mesh with the gears on the intermediate shaft. The secondary shaft is further connected to the output shaft, which, for example, is connected to the drive wheels by means of, for example, a cardan shaft. Each pair of gears has a gear ratio different from the other pair of gears of the gearbox. Different pairs of gears transmit engine torque to the drive wheels, whereby various gear ratios are obtained.

The development of computer technology has also impacted the electronic control and feedback systems of the automobile engine, making them more accurate, increasing their speed and improving their compatibility with existing engines and operating conditions. The entire process of fuel combustion can be precisely controlled in accordance with any working environment. The gas regulator (accelerator) of the car (for example, the accelerator pedal or "gas"), which mainly regulates the fuel supply to the engine, controls the car engine through a system of electrical wires and electronic signals. For this, the accelerator is equipped with sensors that determine its position, in other words, what is required to open the throttle.

When starting the vehicle, AMT uses an automatic disk clutch, such as described above, which is usually controlled using information about the position of the accelerator, engine speed, torque on the engine output shaft, position of the disk clutch and based on the initial position of the disk clutch, which is selected based on when the disk clutch has just begun transmitting torque (traction position), and this position is relatively easy to determine. Torque, usually transmitted in the initial position, can be about 30 Nm. The torque on the engine output shaft is calculated mainly based on the amount of fuel injected into the engine. When the starting sequence and maneuvering are carried out, the vehicle is usually started from a fixed or practically fixed position, while the engine starts the sequence in idle speed mode. The position of the disk clutch and, therefore, the degree of adhesion that determines the torque transmitted from the engine to the gearbox depends mainly on the position of the accelerator selected by the driver. The initial position of the disk clutch is used to provide the driver of the vehicle with a more accurate control when starting the vehicle, since the disk clutch is in its original position immediately after selecting and engaging the gear for starting. The vehicle is ready to move off immediately. Thus, in many situations, the driver feels only a slight sinking when pressing the accelerator pedal, if at all senses it. Thus, the driver receives a theoretically direct response, and the vehicle, in principle, begins to move as soon as the driver begins to squeeze the accelerator pedal.

When choosing the appropriate gear for starting off, AMT usually proceeds from the calculation using at least parameters such as road incline and vehicle weight. Even taking into account the fact that a lot of situations of starting a car are included in this calculation, the choice of gear for starting off can sometimes be incorrect due to a change in the state of the car that cannot be foreseen in the calculation. One of these situations can occur when a truck for long-distance transport is parked on a horizontal section of the road, and its trailer is on a slope. From the point of view of choosing a gear for starting off, this situation can even be aggravated if the trailer and the truck are empty during parking, after which the trailer is loaded before starting off. In this calculation, the change in trailer weight and the fact that it is parked on a slope are probably not taken into account. As a result, AMT is likely to choose too high a gear for pulling away, and it is more likely that pulling away will be unsuccessful due to the increased weight of the trailer and because the trailer is parked on a slope that counteracts traction. The driver will have to interrupt an unsuccessful attempt to pull off and prevent the vehicle from rolling back, for example, by activating the service brake. After that, you will have to manually select an acceptable gear for starting off, since the control unit does not know that a change in conditions has occurred.

WO 0242108 describes one example of a procedure for selecting a gear for starting up when a sequential downshift is performed if the first gear engaged for starting is unable to provide satisfactory acceleration of the vehicle.

However, there is a need to facilitate driver actions in such situations of pulling away, which are mentioned above. This is the main objective of the present invention.

Disclosure of invention

The present invention provides means for solving its problem according to the method according to claim 1 and the device according to claim 6. The remaining items (paragraphs.2-5) relate to the preferred options for implementation and improvements proposed in the invention method.

The present invention provides a method for automatic or semi-automatic selection of the optimal transmission for moving away from the vehicle (hereinafter - the car). The method differs in that in the following order carry out the following steps:

selection and inclusion of the first gear for starting off when the vehicle is stationary,

at the command of the driver, control of the vehicle’s traction torque by gradually connecting the engine to the drive wheels of the vehicle in order to try to make the first start from the vehicle’s position,

determining whether said first gear for starting off the vehicle is too high under the present conditions of the first driving off of the vehicle,

if the first gear for starting off the vehicle is too high, the interruption of the first starting off of the vehicle and automatic braking of the vehicle,

disabling said first gear for starting off the vehicle,

selecting and engaging an adapted second gear for starting off, which is lower than said first gear for starting off and has a higher gear ratio,

controlling the vehicle’s driving torque by gradually connecting said engine assembly to said drive wheels in order to try to make a second pull-off from the vehicle’s position, and

if, as a result of the second attempt to pull away from the vehicle, the drive torque is transmitted to the drive wheels of the vehicle, sufficient to drive off, stop the vehicle from braking.

An advantage of the method proposed in the invention is that an incorrectly selected gear for starting off automatically or semi-automatically shifts. One of the additional advantages is that the gear shift for starting off can be carried out in an uphill position. Thus, you can shift the wrong gear to move away without the risk of the car rolling back in the wrong direction.

According to a preferred second embodiment of the method of the invention, a step in which it is determined that said first pulling away from the vehicle is not possible in said first gear to pull away is calculated by calculating the thermal energy generated in the clutch during the first pulling away from the vehicle , and interrupting said first attempt to pull off the vehicle if said thermal energy exceeds a predetermined limit of thermal energy

According to one of the preferred additional embodiments of the method proposed in the invention, the driver can carry out the step of determining that said first pulling away from the vehicle in said first gear for starting off. Subsequent interruption of the first pulling away from the vehicle may also be performed manually by the driver. Thus, the driver is given greater freedom of action. The driver can manually interrupt the first starting from the vehicle by choosing a lower gear, for example, using the gear lever.

According to one additional preferred embodiment of the method according to the invention, if, as a result of a second attempt to pull away from the vehicle, a sufficient torque is transmitted to the drive wheels of the vehicle at least to keep the vehicle stationary, the clutch engagement control continues will not be fully turned on and the car will not move. This moment of inclusion is an additional sign of the successful selection of the gear for starting and the process of turning on the gear.

Further preferred embodiments of the invention are disclosed in the dependent claims.

Brief Description of the Drawings

Further, the present invention is described in more detail with reference to the accompanying drawings, in which, by way of example, further preferred embodiments of the invention are illustrated:

figure 1 schematically shows one embodiment of a device for solving the problems of the invention,

2 and 3 are two different flowcharts illustrating the various steps of two different embodiments of the invention,

4 is a diagram of a computer device applicable according to one embodiment of the invention.

Description of Preferred Embodiments

Figure 1 schematically shows a circuit 1 of a car drive with a brake device 6, which in the illustrated example serves to brake the drive wheel 5 of the car. Said wheel 5, in a known manner, drives the motor unit 2 by means of a stepwise automatic transmission 3, 4 and a cardan shaft 8. The automatic transmission can be a clutch 3 and an automatic mechanical transmission 4 or a transmission 3 and 4 with two clutches or a torque converter 3 and an automatic gearbox 4 gears. The engine unit may be an internal combustion engine or a combined unit consisting of an internal combustion engine and an electric motor / generator, a so-called hybrid electric vehicle. In the illustrated example, as a brake device 6, a service brake is shown which can be controlled in a known manner, for example, by a car driver using a brake pedal (not shown). The invention also provides the possibility of using other braking devices in the car in combination with the service brake or instead of the service brake, such as auxiliary brakes or electric brakes (for example, said engine / generator) for braking the car.

The engine unit 2 and its output torque, automatic transmission 3, 4 and the brake device 6 can be controlled by a control unit 7 in accordance with various input signals, such as the engine speed, the input / output shaft speed of the transmission, the selected transmission and command driver transmitted in a known manner by, for example, an accelerator pedal and a brake pedal. In one alternative embodiment, the control unit may consist of two or more control units connected, for example, via a network. Between said control units, said control functions according to the invention can be divided.

In one embodiment of the invention, the control unit 7 is programmed to select and engage the first gear for starting from the vehicle when the vehicle is stationary and the transmission is disconnected from the engine 2. See FIG. 2, step S2 in the block diagram for the control the sequence starts in step S1. For example, a starting gear may be automatically selected and engaged if the driver selects automatic mode by a gear lever (not shown). The driver can also choose a gear for starting off even manually, despite the fact that the gear itself is engaged in by the control unit. The fact that the transmission 3, 4 is disconnected from the engine, can mean, for example, the clutch 3 between the engine and the speed transmission (DCT or AMT with clutch) is off or there is no oil in the torque converter, which means that the torque converter will not transmit torque from the engine assembly of a speed transmission. The control unit 7 is additionally programmed by the driver’s command, for example, transmitted via the accelerator pedal, to regulate the vehicle’s traction torque generated by the engine and to connect the transmission to the engine so as to try to start the vehicle first (step S3 in FIG. 2 ) The attempt to pull off as such is carried out in the usual way. So, with the gradual connection of the engine assembly with the transmission, an increasing torque developed by the engine assembly is transmitted to the drive wheel. If the first gear for starting off is too high, that is, the gear ratio is too low, excessive clutch wear will occur when the transmission is a plate-type clutch, such as in an automatic-clutch AMT or DCT. This wear can be measured by calculating the thermal energy generated during slipping clutch. This can be done by multiplying the torque by the difference in rotational speeds in the clutch and integrating the resulting product over time. If the result of calculating the heat generated during slipping of the clutch during the first pull-out of the vehicle exceeds a predetermined value, according to the invention, the control unit is programmed to regard this as the first gear for pulling off is too high a gear for pulling away (step S4 and the case "Yes" in figure 2). Therefore, the first gear for starting off is selected incorrectly for the present situation of starting the car. If the gear for starting off is not too high, the control unit is programmed to complete the attempt to start off (step S5 and the case of “No” in FIG. 2).

If the gear for starting off is too high, the control unit 7 automatically interrupts (step S6) the first pulling away from the vehicle and brakes the vehicle by applying the braking device and then disengaging (step S7) the first gear for starting off. After the braking device is activated, the car stops and (or) its rollback is prevented in the direction opposite to the selected direction of movement, for example, when starting on an ascent on a slope. After turning off the first gear for starting off, the control unit is programmed to select and engage the second gear for starting off, which is lower than the first gear for starting off (step S8), and therefore has a higher gear ratio, than the first gear for starting off. In one embodiment of the invention, the control unit may be programmed to directly select the lowest possible gear for starting off after an interrupted first attempt to start off. After switching on the second gear for starting off, the control unit is programmed to start a second attempt to start off from the vehicle (step S9) by adjusting the traction torque created by the engine and engaging the transmission in such a way as to carry out the second starting from the vehicle. The sequence shown in FIG. 2 ends upon completion of the second pullaway attempt at the lowest gear possible for pullaway.

The first attempt to pull off the car was initiated by a driver who manipulates, for example, the accelerator pedal to request a specific output torque from the engine. In accordance with this driver’s command, the control unit controls the engine and clutch (or torque converter) in a predetermined manner. Since the driver is able to continue to request the same output torque until the second pull-out attempt, he can continue to request the same output torque during both pull-out attempts. If, as a result of the second attempt to pull away from the vehicle, a sufficient torque is transmitted to the drive wheel 5 to move away, according to the invention, the control unit is programmed to turn off the brake device 6 (see also step S9). The brake device can be switched off gradually in a predetermined adjustable manner in accordance with a gradual increase in the torque transmitted to the drive wheel. Said adjustable brake release is known per se. During a second pull-out attempt, clutch wear can also be measured by calculating thermal energy and comparing with a predetermined value. If the calculated value of thermal energy is less than the specified value, and the torque transmitted to the drive wheel 5 is sufficient so that the car remains at least in a stationary position and the brake device 6 is off, the control unit is programmed to continue to engage the clutch until it is fully engaged , and the car will not move.

In one of the alternative embodiments of the invention shown in FIG. 3, the described start-up process can be repeated until a gear for starting is selected and used for starting. So, the gear for starting off can be lowered one step at a time. The steps S31-S39 illustrated in FIG. 3 correspond to steps S1-S9 in FIG. 2. The difference between them is that when performing the sequence shown in FIG. 3, in step S38, instead of selecting the lowest possible gear for starting, the next lower gear for starting is selected. As shown in FIG. 3, in step S310, the control unit is programmed to determine whether the second gear for starting off is also too high. If this is not the case, the pullaway attempt continues at step S311 until it is completed, if so, the control unit is programmed to return to step S36, abort the pullaway attempt and prepare for yet another pullaway attempt in an even lower gear for pulling off from place.

In one of the additional embodiments, the control unit may be programmed to evaluate how unsuccessful the first attempt to pull off, and, based on this, choose an adapted lower second gear to pull off. For example, if the first attempt to move off is carried out in third gear, the second attempt to move off the control unit may select second gear or first gear. The decision to select one of the aforementioned lower gears can be made by the control unit, which is programmed to calculate heat energy again during clutch slipping, and also record the input gearbox shaft speed as additional information. Thus, the control unit is able to assess how close to success was the attempt to pull off. If the input shaft speed was relatively low, the first gear (which in this case is also the lowest gear possible) will be selected as a new gear for starting off. If the input shaft speed was relatively high, the second gear will be selected as the next gear for starting off.

One of the additional parameters that can be taken into account by the control unit 7 in all of the aforementioned embodiments of the invention may be the rotation speed of the motor unit, that is, the speed determines the available output torque of the motor unit, which allows to transmit a certain torque to the drive wheels and to successfully start with places.

In one of the alternative embodiments of the invention shown in FIG. 2, step S3, in which it is determined that the first pulling away from the vehicle is not possible in the first gear to pull off, can be performed by the driver. So, if the driver notices that the selected and engaged gear for starting off is too high, the driver can interrupt the attempt to move off, for example, by directly selecting another gear for starting off using the gear lever. The driver can choose the lowest gear possible (corresponds to step S8) or simply select a lower gear than the first gear to move off (corresponds to step S38). This interruption and the selection of the gear for starting off manually causes the control unit 7 to automatically perform the steps corresponding to steps S6-S10.

In one of the additional embodiments, the driver can shift the selected gear for starting off even before the start of the attempt to move off, that is, before the driver initiates starting, for example, depressing the accelerator pedal. Thus, after manually selecting a lower second gear for starting off in such an embodiment, the control unit 7 is automatically prompted to perform the steps corresponding to steps S6-S10.

The above-mentioned two variants of the invention using semi-automatic driver initiation can be combined with each other or with the other variants of the invention described above using the fully automatic selection of the optimal gear for starting off.

Of course, embodiments of the invention are possible in which the car has only functionality according to the above-described embodiments using fully automatic selection of the optimal gear for starting off.

In all of the above embodiments, the control unit may be programmed to alert the driver in the event that it is not possible to pull off in the lowest gear without the risk of severe transmission wear.

FIG. 4 shows a device 500 according to one embodiment of the invention, comprising a non-volatile memory 520, a processor 510, and a read-write memory 560. The memory 520 has a first area 530 in which a computer program for managing the device 500 is stored. The computer program for managing the device 500 stored in the memory area 530 may be an operating system. The device 500 may be placed, for example, in a control unit, such as a control unit 7. The data processing unit 510 may be, for example, a microcomputer.

The memory 520 also has a second region 540 in which the engine, clutch, transmission and brake control program according to the invention is stored. In one alternative embodiment, the program with functions according to the invention is stored in a separate non-volatile storage medium (medium) 550, such as, for example, a compact disk or a semiconductor memory with removable disks. The program may be stored in executable form or in compressed form.

When it is further indicated that the data processing unit 510 performs a specific function, it should be clear that the data processing unit 510 executes a specific part of the program stored in the memory 540 or a specific part of the program stored in the non-volatile recording medium 550.

Data processing unit 510 is designed to communicate with memory 550 via data bus 514. The data processing unit 510 is also designed to communicate with the memory 520 via the data bus 512. In addition, the data processing unit 510 is designed to communicate with the memory 560 via the data bus 511. The data processing unit 510 is also designed to communicate with the data port 590 by using the data bus 515.

The method of the present invention may be implemented by a data processing unit 510 that executes a program stored in memory 540 or a program stored in a non-volatile recording medium 550.

The invention should not be considered limited by the embodiments described above, and a number of additional options and improvements are contemplated within the scope of the following claims.

Claims (8)

1. The method of automatic or semi-automatic selection of the optimal gear for starting off the vehicle, characterized in that the following steps are carried out: selecting and engaging the first gear for starting off when the vehicle is stationary (steps S2, S32), at the command of the driver, control of the vehicle’s driving torque by gradually connecting the engine to the drive wheels of the vehicle in order to try to implement the first driving away from the vehicle (steps S3, S33), determining whether the first gear for starting off the vehicle is too high under the conditions of the first driving off the vehicle (steps S4, S34) if the first gear is moving away the vehicle is too high, interruption of the first pulling away and automatic braking of the vehicle (steps S6, S36), disabling said first gear for starting off the vehicle (steps S7, S37), selection and the inclusion of an adapted second gear for starting off, which is lower than the first gear for starting and has a higher gear ratio (steps S8, S38), controlling the vehicle’s traction torque by gradually connecting the engine to the drive units wheels to try to make a second start, and if, as a result of a second attempt to start, a sufficient torque is transmitted to the drive wheels of the vehicle to pull off, stop braking the vehicle (steps S9, S39). 2. The method according to claim 1, characterized in that the determination that the first pulling away is not possible in the said first gear for pulling off is carried out on the basis of calculating the heat energy generated in the clutch during the first pullaway attempt said first attempt to pull off is carried out if said thermal energy exceeds a predetermined limit of thermal energy. 3. The method according to claim 1, characterized in that the driver makes the determination that the first pull-out is not possible in said first gear for pulling off, and the driver also manually performs the next step of interrupting the first pull-off. 4. The method according to claim 3, characterized in that the driver interrupts the first pulling away by manually selecting a lower gear. 5. The method according to one of the preceding paragraphs, characterized in that if, as a result of the aforementioned second attempt to move away, a sufficient torque is transmitted to the drive wheels of the vehicle, at least enough to keep the vehicle stationary, the control is continued engaging the clutch until it is fully engaged and the vehicle does not move (steps S10, S310). 6. The method according to claim 1, characterized in that said selection of an adapted second gear for starting off is carried out on the basis of an assessment of how unsuccessful the said first attempt to move off was. 7. A vehicle having a motor unit (2), connected with the possibility of transmitting a drive force to a stepped automatic transmission (3, 4), which is connected with the possibility of transmitting a drive force to the drive wheels (5) of the vehicle, a brake device (6), capable of stopping a vehicle, at least a control unit (7) for controlling a motor unit, an automatic transmission and a brake device in accordance with various input signals, characterized in that the wrinkled control unit (7) is configured to carry out the following operations in the following order: first gear is selected for starting up when the vehicle is in a stationary position (steps S2, S32) and the transmission is disconnected from the engine, on the driver’s command the engine unit with the vehicle's driving torque and the connection of the transmission and the engine unit by gradually connecting the engine unit to the drive wheels of the trans a sports vehicle, in order to try to make the first start from the vehicle (steps S3, S33), determining whether said first gear for starting from the vehicle is too high under the existing conditions of the first starting from the vehicle (steps S4, S34), if the first gear for starting off the vehicle is too high, the interruption of the first starting off and automatic braking of the vehicle's engine assembly by driving the brake device (steps S6, S36), disabling said first gear for starting off the vehicle (steps S7, S37), selecting and engaging an adapted second gear for starting off, which is lower than said first gear for starting off from the spot and has a higher gear ratio (steps S8, S38), control of the vehicle’s driving torque generated by the engine and connecting the transmission by gradually connecting the engine to the leads with other wheels to try to make a second start, and if, as a result of the second attempt to start, a sufficient torque is transmitted to the drive wheels of the vehicle to move off, the brake device will be disengaged (steps S9, S39). 8. The vehicle according to claim 7, characterized in that said control unit is configured to select said adapted second gear for starting, based on an assessment of how unsuccessful said first attempt to move off.

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