SUNDHOLM, Per (Mikael Wincklersväg 22, Nykvarn, S-155 30, SE)
Claims
1. Method for improving drivability of a motor vehicle having a droop function, said method comprising the step of:
- deactivating said droop function in at least one predetermined first vehicle condition.
2. Method according to claim 1 , comprising the further step of:
- activating said droop function in at an at least one predetermined second vehicle condition.
3. Method according to claim 1 or 2, wherein said first vehicle condition comprises starting off of the vehicle.
4. Method according to any preceding claim, wherein said first vehicle condition comprises a gear box of the vehicle being in neutral position; and/or the speed of the vehicle being substantially zero (0); and/or when a RQV-mode is active.
5. Method according to any of claims 2-4, wherein the second condition comprises said vehicle moving at a certain predetermined speed; and/or in connection to gear engagement.
6. Method according to any of claims 2-5, wherein the droop function, during a certain phase of the droop activating step is successively activated.
7. Method according to claim 6, wherein said phase corresponds to a certain degree of increase of clutch engagement.
8. Method according to any preceding claim, comprising the steps of:
- during said first vehicle condition generating, by means of a regulator, a first torque value signal based upon a requested engine speed value; and
- controlling the engine of the vehicle based upon said first torque value signal.
9. Method according to claim 8, comprising the steps of:
- when using a vehicle having an automated transmission, generating a second torque value signal; and
- after a step of shifting from a RQV-mode to RQ-mode, controlling the engine of the vehicle based upon said second torque value signal.
10. Method according to claim 9, comprising the step of:
- determining a difference between the first and second torque value signal; and
- processing said second torque value signal based upon said difference.
11. Computer program for improving drivability of a motor vehicle having a droop function, comprising computer readable program code means for causing an electronic control unit or another computer connected to the electronic control unit to perform the step of:
- deactivating said droop function in at least one predetermined first vehicle condition.
12. Computer program according to claim 11 , comprising computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the step of:
- activating said droop function in at an at least one predetermined second vehicle condition.
13. Computer program according to claim 11 or 12, wherein said first vehicle condition comprises starting off of the vehicle.
14. Computer program according to any of claim 11-13, wherein said first vehicle condition comprises a gear box of the vehicle being in neutral position; and/or the speed of the vehicle being substantially zero (0); and/or when a RQV-mode is active.
15. Computer program according to any of claims 12-14, wherein the second condition comprises said vehicle moving at a certain predetermined speed; and/or in connection to gear engagement.
16. Computer program according to any of claims 12-15, wherein the droop function, during a certain phase of the droop activating step is successively activated.
17. Computer program according to claim 16, wherein said phase corresponds to a certain degree of increase of clutch engagement.
18. Computer program according to any of claims 11-17, comprising computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the steps of:
- during said first vehicle condition generating, by means of a regulator, a first torque value signal based upon a requested engine speed value; and
- controlling the engine of the vehicle based upon said first torque value signal.
19. Computer program according to claim 18, comprising computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the steps of:
- when using a vehicle having an automated transmission, generating a second torque value signal; and
- after a step of shifting from a RQV-mode to RQ-mode, controlling the engine of the vehicle based upon said second torque value signal.
20. Computer program according to claim 19, comprising computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the steps of:
- determining a difference between the first and second torque value signal; and
- processing said second torque value signal based upon said difference.
21. Computer, such as an embedded electronic control unit or a vehicle external computer comprising a storing means and a computer program according to any of claims 11-20 stored in the storing means.
22. Vehicle comprising a computer according to claim 21.
23. Vehicle according to claim 22,
wherein said vehicle is heavy vehicle, such as a truck or bus. |
Method and computer program for improving drivability of a motor vehicle
Technical field
The present invention relates to a method for improving drivability of a motor vehicle. The invention also relates to a computer program product comprising computer program code for implementing a method according to the invention. The invention further relates to a computer and a vehicle having a computer onboard.
Background art
Today there exists at least two different systems comprising accelerator pedals for heavy vehicles, such as trucks or buses. Herein a first type of system comprises an accelerator pedal referred to as RQ-pedal, which system is arranged to directly control fuel supply to the combustion chambers of the engine or torque. Also, herein a second type of system comprises an accelerator pedal referred to as RQV-pedal, which system is arranged to generate an engine reference speed value and which via a regulator requests a certain amount of fuel supply to the combustion chambers of the engine or torque. These two systems are known in the art.
When starting off from standing still with a vehicle having a manual gearbox or an automatic gearbox, and a clutch some inconveniences are recognized. Usually a driver of the vehicle requests an engine speed being above an idle engine speed before he or she controls the clutch to engage within the vehicle drive train. However, if there is high driving resistance, such as if the vehicle carries a heavy load or when starting off in uphill slope, the engine may have difficulties to keep the desired engine speed, which may lead to that the actual engine speed drops to idle engine speed, which is undesirable.
To increase vehicle drivability, the vehicle may be provided with a so called droop function, which is an implemented functionality designed to reduce engine reference speed when engine torque is increased. The droop function
may for instance be implemented in the second type of system comprising the RQV-pedal.
The droop-function is an additional function associated with the RQV- accelerator pedal. In principle the droop-function is decreasing the engine reference speed of the RQV-pedal when the engine torque is increased, and vice versa. As a consequence there is provided a higher "resolution" of the accelerator pedal.
For example, say that the accelerator pedal is calibrated such that an upper, initial position of the accelerator corresponds to 500 rpm and a fully depressed position of the accelerator corresponds to 2500 rpm. A resolution thereof is then 20 rpm on a percentage scale. To increase the resolution the droop function could be calibrated such that the resolution thereof would be 10 rpm on the percentage scale.
EP 930424 depicts a vehicle having manual gearbox and an accelerator pedal corresponding to a RQV-pedal. However, the vehicle depicted in EP 930424 may start off even though a driver thereof does not uses the accelerator pedal. EP 462414 is another document depicting relating prior art.
Summary of the invention
An object of the invention is to provide a new and advantageous manner of increasing drivability of a vehicle.
Another object of the invention is to provide a method and computer program for improving drivability of a vehicle.
An object of the invention according to an aspect of the invention is to provide a method for further improving drivability of a vehicle.
An object of the invention according to an aspect of the invention is to provide an alternative method for improving drivability of a vehicle during take off from standing still.
These objects are achieved by a method for improving drivability of a motor vehicle having a droop function, said method comprising the step according to claim 1. By deactivating the droop function when the vehicle is in predetermined condition increased vehicle drivability is achieved. In particular, vehicle drivability is increased when starting off the vehicle from standing still, since a higher should engine speed value may provided when the droop function is deactivated. The first vehicle condition may thus comprise starting off of the vehicle. The first vehicle condition may comprise a gear box of the vehicle being in neutral position. The first vehicle condition may be when the speed of the vehicle is substantially zero (0). The first vehicle condition may be when a RQV- mode is active.
The term "starting off' refers to an initiation phase. The term "starting off' may refer to a phase comprising a time period from when the vehicle is standing substantially still till a certain speed relative ground has been achieved. The term "starting off' may refer to a phase comprising disengaging the vehicle clutch, engaging a gear and engaging the clutch again.
The method may comprise the step of activating said droop function in at least one predetermined second vehicle condition. Since the droop function itself functions well during driving of the vehicle, it is advantageous to activate the droop function after starting off, such as when the vehicle has reached a certain speed relative ground, or after a predetermined period of time has lapsed after starting off, e.g. 5 seconds. The second condition may thus comprise said vehicle moving at a certain predetermined speed. The second condition may also be a state in connection to gear engagement. It is advantageous to activate the droop function after a first gear has been engaged after taking off.
The droop function, during a certain phase of the droop activating step, may be successively activated. This has the positive effect of activating the droop function in a smooth way. In other words, the droop function is according to an embodiment ramped. The phase may correspond to a certain degree of increase of clutch engagement. Advantageously this certain degree of increase of clutch engagement corresponds to a clutch pedal being brought back
towards an initial position some last few percent of the distance between a fully depressed pedal state and the initial position state. By ramping the droop function in this way, driver comfort is increased.
The method may further comprise the steps of during said first vehicle condition generating, by means of a regulator, a first torque value signal based upon a requested engine speed value; and controlling the engine of the vehicle based upon said first torque value signal. This holds true for various setups of gearboxes during a starting off phase of the vehicle.
The method may further comprise the steps of when using a vehicle having an automated transmission, generating a second torque value signal; and after the step of shifting from a RQV-mode to RQ-mode, controlling the engine of the vehicle based upon said second torque value signal. A control unit of the vehicle may comprise routines for managing different kinds of gearboxes, and may also comprise routines for managing a shift between a RQV-mode to RQ- mode based upon determined vehicle conditions. Thus, a control unit of the vehicle may be prepared so as to be suitable for different vehicles having different gearboxes and thereto applicable control systems, such as Scania "Opticruise".
The method may further comprise the steps of determining a difference between the first and second torque value signal; and processing said second torque value signal based upon said difference. This has the effect of providing a smooth shift between a RQV-mode and a RQ-mode. The determined difference between the first torque value signal and the second torque value signal is advantageously added to the second torque value signal. The first torque value signal is according to an example an output torque signal relating to the RQV-mode. The second torque value signal is according to an example an output torque signal relating to the RQ-mode. Thus, there is provided an advantageous way of shifting modes in a simple and reliable manner. Activation of the RQ-mode may according to an embodiment be performed by a ramping procedure, based upon said torque value difference.
The objects are also achieved by a computer program for improving drivability of a motor vehicle having a droop function, comprising computer readable program code means for causing an electronic control unit or another computer connected to the electronic control unit to perform the step according to claim 11.
The computer program may comprise computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the step of:
- activating said droop function in at least one predetermined second vehicle condition.
The objects are also achieved by a computer, such as an embedded electronic control unit or a vehicle external computer comprising a storing means and a computer program, for improving drivability of a motor vehicle having a droop function according to the invention, stored in the storing means.
The invention also relates to a vehicle comprising the computer. The vehicle may be a truck or bus.
A beneficial contribution of the invention is that a cost effective solution to the above stated problems is achieved. The method is simple to implement into existing vehicles and it is further easy to modify and upgrade a computer program comprising code means for performing the inventive method by using a communication terminal being arranged for communication with the a control unit comprising said code means.
Yet another beneficial contribution of the invention is that the method for improving drivability is robust.
The procedure of starting off a vehicle from standing still is improved, in particular if the driving resistance is high. The driver of the vehicle will probably experience the engine to be stronger since the engine will have an increased ability to keep the desired engine speed without the driver having to give more
gas during engagement of the clutch within the drive train. The invention will therefore provide increased comfort to a driver of the vehicle. Also, since the engine achieves a better ability to keep desired engine speed when starting off the vehicle from standing still, this will lead to less drive train transients.
By using the inventive method wear of the clutch of the drive train is reduced since the time required for engaging the clutch during gear shifts is shortened.
A driver of the vehicle will probably experience it to be easier to actively regulate the engine speed by means of the accelerator pedal when the gear box is in neutral position or if the clutch pedal is depressed.
Additional objects, advantages and novel features of the present invention will become apparent to those skilled in the art from the following details, as well as by practice of the invention. While the invention is described below, it should be understood that the invention is not limited to the specific details disclosed. A person skilled in the art having access to the teachings herein will recognise additional applications, modifications and embodiments in other fields, which are within the scope of the invention.
Brief description of the drawings
For a more complete understanding of the present invention and further objects and advantages thereof, reference is now made to the examples shown in the accompanying drawings, in which:
Figure 1 schematically illustrates a vehicle according to an aspect of the present invention; Figure 2 schematically illustrates a sub-system of a vehicle according to an aspect of the present invention;
Figure 3a schematically illustrates a signal scheme according to an aspect of the invention;
Figure 3b schematically illustrates a signal scheme according to an aspect of the invention;
Figure 4 schematically illustrates a flow chart depicting a method for operating a drive train of a vehicle according to an aspect of the present invention; and Figure 5 schematically illustrates an electronic control unit according to an aspect of the invention.
Detailed description of the drawings
With reference to Figure 1 , a side view of a vehicle 100 is shown. The vehicle 100 may be a heavy vehicle, such as a truck or bus. The vehicle 100 may alternative be a private car. However the vehicle 100 in this example comprises a tractor 110 and a trailer 112.
Hereinafter the term "link" refers to a communication link which may be a physical connector, such as an optoelectronic communication wire, or a non- physical connector such as a wireless connection, for example a radio or microwave link.
With reference to Figure 2, a sub-system 299 of the vehicle 100 is shown. The sub system 299 comprises a drive train arrangement of the vehicle 100.
There is schematically illustrated a drive train of the motor vehicle 100 as shown in Figure 1. The drive train has an internal combustion engine 230 which is controlled by an electronic control unit 200. For this purpose, the control unit 200 is signal-connected to actuating members (not illustrated), such as, for example, a throttle valve adjuster, and sensors, such as, for example, rotational speed sensors. The combustion engine 230 is connected via a shaft 231 , a clutch 235, and shaft 236 to a gearbox 240. The gearbox 240 is arranged to propel a number of wheels 245 of the vehicle 100 in a known fashion.
The control unit 200 is signal-connected to a power actuating member 220 for example, an accelerator pedal. A driver of the vehicle can set a desired engine speed value of the internal combustion engine 230 by means of the power actuating member 220. In particular this invention is directed to situations where the vehicle 100 is standing still, and where a driver is about to start off by
speeding up the vehicle by entering a first gear, such as, for example, the first lowest gear.
According to this example the electronic control unit 200 is arranged to control each of the internal combustion engine 230, clutch 235 and the gearbox 240. However, a gear box control unit (not shown) may be arranged for communication with the electronic control unit 200 and/or for direct communication with the clutch 235 and gearbox 240 so as to control the clutch and the gearbox 240.
Here, according to an example, the inventive method is initiated and controlled by means of the electronic control unit 200. According to one example the electronic control unit 200 is an electronic engine control unit. Alternatively, the inventive method is initiated and controlled by means of an external computer 210. The external computer 210 may be directly connected to the electronic control 200 unit via a link 215, but may also be indirectly connected to the electronic control unit 200 in any suitable manner, such as through an internal vehicle network. The communication between the external computer and the electronic control unit 200 may be partly or entirely wireless. The inventive method could also be initiated and controlled by the electronic control unit 200 itself or by another electronic control unit, such as an electronic gear box control unit.
The electronic control unit 200 is arranged for communication with a communication terminal 280 via a link 285. Also, the external computer 210 is arranged for communication with the communication terminal via a link 286. The communication terminal 280 may be provided with a display and a user interface so as to allow a user to interact with the electronic control unit 200. The communication terminal 280 is arranged to display information relevant to the method of the invention, such as a torque difference value between a value of an output torque signal associated with the RQ-mode and/or the RQV-mode.
Figure 3a schematically illustrates a signal scheme. It is illustrated that this vehicle sub-system is provided with one mode, namely a RQV-mode. It can be seen that, in case of the vehicle being in a RQV-mode, a droop-function signal
DFS will be added at 310 to a desired engine speed value signal RPMreflN. The desired engine speed value signal RPMreflN is set by a driver using the power actuating member 220, which is depicted with reference to Figure 2. By adding the droop-function signal DFS to the desired engine speed value signal RPMreflN the desired engine speed value will be adjusted according to a predetermined way, as known in the art.
It is also illustrated that the desired engine speed value signal RPMreflN, which may have been manipulated by the droop function signal, and therefore is referred to as RPMrefOUT, may be further manipulated at a point 315. At the point 315 the engine speed value signal RPMrefOUT may be added or subtracted to a predetermined engine speed value compensation signal (not shown). According to one example the engine speed value signal RPMrefOUT may be subtracted with an actual engine speed value signal so as to achieve a difference referred to as regulating error. This regulating error signal may be inputted from the point 315 to a regulator 330. The regulator 330 is arranged to generate an output torque signal RQVtq. The regulator 330 is arranged to regulate an output torque signal RQVtq based upon the desired engine speed value signal RPMreflN or other inputs such as the regulating error signal. The generated output torque signal may be used to control the engine of the vehicle. The regulator 330 may for example be a PID-controller.
According to the inventive method, when the vehicle is in a predetermined first vehicle condition, the droop function DFS is deactivated. This may be performed by multiplying a start mode signal SMS by the droop-function signal DFS at 320. The start mode signal SMS may be either of a value one (1 ) or a value zero (0). Thus, when the start mode signal SMS is fed to the point 320 and has a value zero (0) the droop function signal DFS is deactivated.
According to one example, when the driver presses down the clutch pedal more than to a predetermined position, say 5% of a position corresponding to a fully pressed down position of the pedal, there is provided a start mode signal SMS being equal to zero to point 320, which results in that the droop-function of the vehicle is deactivated.
According to one example, when the driver during starting off the vehicle brings back the clutch pedal up to a position closer than a predetermined position, say 95% of a position corresponding to a fully brought back position of the pedal, there is provided a start mode signal SMS which is variable between a value zero and a value 1 , and linearly dependent on predetermined time, e.g. 5 seconds, to point 320, which results in that the droop-function of the vehicle is smoothly activated.
According to one example, when the driver during starting off the vehicle fully have brought back the clutch pedal to the initial position, there is provided a start mode signal SMS being equal to one (1 ) to point 320, which results in that the droop-function of the vehicle is activated.
The start mode signal SMS is substantially equal to one (1 ), in a case where the power actuating member 220 is in a particular state. According to one example, this means that before starting off the driver does not presses down the accelerator pedal at all, there is provided a start mode signal being equal to one to point 320, and wherein the droop-function is active. This is advantageous in a case where engine power is used for other purposes than driving wheels of the vehicle, such as powering an AC-unit for cooling the cabin of the vehicle.
The start mode signal SMS is substantially equal to a value between zero (0) and one (1 ), in a case where the clutch pedal is in a predetermined state. This state corresponds to a state where the driver presses down the clutch pedal from an initial first position to a predetermined second position being separated from the initial first position. During this state there is provided a start mode signal SMS which is continuously changing from one (1 ) to zero (0) resulting in that the droop-function is successively and, thus, smoothly deactivated.
Figure 3b schematically illustrates a signal scheme. It is illustrated that this vehicle sub-system is provided with two different modes, namely a RQV-mode as depicted with reference to Figure 3a and a RQ-mode. During starting off the vehicle the RQV-mode is used, irrespective of which type of transmission is provided. In case the provided transmission is of automated type a switch from the RQV-mode to the RQ-mode is performed according to a predetermined
criterion. For example such a switch may be performed when or after the droop function no longer is deactivated during starting off the vehicle. It should be noted that a desired engine speed value set by a driver using the power actuating member 220, which is depicted with reference to Figure 2, in case of the vehicle being in the RQ-mode, results in that the electronic control unit 200 will generate a torque signal RQtq. The generated output torque signal RQtq may be used to control the engine of the vehicle.
When shifting from a RQV-mode to a RQ-mode a difference between the generated output torque signal RQVtq and the generated output torque signal RQtq is determined. This difference of value between the RQVtq signal and the RQtq signal is used to modify the RQtq signal before said shifting is performed. The RQtq signal is modified so as to achieve a smooth shift between the RQV- mode and the RQ-mode.
The regulator 330 is arranged to generate an output torque signal RQVtq. The generated output torque signal may be used to control the engine of the vehicle.
Below is three different example situations schematically depicted.
Example 1. Description of a course of events in a vehicle being provided with a clutch pedal and a RQ-regulator being in an active mode.
Situation: The gear box of the vehicle is in neutral position. No gear is engaged. The vehicle is standing still. The RQV-mode is active. The droop functionality of the RQV-regulator is deactivated.
1. The driver depresses the clutch pedal, engages a gear, e.g. a first lowest gear, and starts to release the clutch pedal so as to slip the clutch. The RQV- mode is still active. The droop functionality of the RQV-mode is still deactivated.
2. The clutch pedal reaches a top position and a difference between the engine's actual output torque and the torque outputted from the RQ-regulator is calculated. This difference of torque is added to the output torque value of the RQ-regulator and the RQ-regulator is subsequently activated and the RQV- regulator is deactivated.
3. During a predetermined time period, say in a time interval of 0.5-5 seconds, or alternatively 1-3 seconds, after the shift from RQV-mode to RQ-mode the torque difference between the RQVtq signal and the RQtq signal is ramped towards zero (0) and the RQ-mode is thereby activated.
Example 2. Description of a course of events in a vehicle not being provided with a clutch pedal and a RQ-regulator being in an active mode.
Situation: The gear box of the vehicle is in neutral position. No gear is engaged. The vehicle is standing still. The RQV-mode is active. The droop functionality of the RQV-regulator is deactivated.
1. The driver of the vehicle is engaging a gear, e.g. a first lowest gear. At this moment there is being performed a shift from a RQV-regulator control to RQ- regulator control, i.e. a shift from a RQV-mode to a RQ-mode.
Example 3 Description of a course of events in a vehicle having a RQV- regulator being in an active mode.
Situation: The gear box of the vehicle is in neutral position. No gear is engaged. The vehicle is standing still. The RQV-mode is active. The droop functionality of the RQV-regulator is deactivated.
1. The driver depresses the clutch pedal, engages a gear, e.g. a first lowest gear, and starts to release the clutch pedal so as to slip the clutch. The RQV- mode is still active. The droop functionality of the RQV-regulator is still deactivated.
2. The clutch pedal reaches a top position and at a predetermined moment the droop functionality is activated smoothly during a ramping procedure.
Figure 4 schematically illustrates a method for improving drivability of a motor vehicle having a droop function.
The method comprises a first method step s410. The method step s410 comprises the step of in a control unit of the vehicle, such as an electronic engine control unit, receiving input data. The input data comprises information
relevant for determining if the vehicle is in a first predetermined vehicle condition. The input data may be sent by different sensors or another control unit of the vehicle, such as a transmission control unit. The input data may comprise information about vehicle speed relative ground and/or if the gearbox of the vehicle is in neutral position and/or to what extent the clutch of the transmission is engaged, e.g. fully engaged, completely disengaged, or to what degree the clutch is disengaged. After the method step s410 a subsequent method step s415 is performed.
The method step s415 comprises the step of determining whether the vehicle is in at least one first vehicle condition or not. The first vehicle condition is a predetermined condition. The first vehicle condition is a preset condition. The first vehicle condition may be a condition characterized by that the vehicle is starting off from standing still. Another first vehicle condition may be a condition wherein the gear box of the vehicle is in neutral position. Another first vehicle condition may be a condition wherein the speed of the vehicle is substantially zero meters per second (Om/s). Another first vehicle condition may be a condition wherein the RQV-mode of the vehicle is active. If it is determined that the vehicle is in a first vehicle condition a subsequent method step s420 is performed. If not, the method step 410 is performed, namely more input data will be received.
The method step s420 comprises the step of deactivating the droop function. This may be performed by multiplying a droop function signal with a start function signal having a value zero (0) as illustrated in the figures 3a and 3b. After the method step s420 a subsequent method step s425 is performed.
The method step s425 comprises the step of determining whether the vehicle is in at least one second vehicle condition or not. The second vehicle condition is a predetermined vehicle condition. The second vehicle condition is a preset vehicle condition. The second vehicle condition may be a condition characterized by that the vehicle is moving at a certain predetermined speed relative ground. One example of this second vehicle conditions are that the vehicle is moving at a minimum speed of 5km/h. Another second vehicle
condition may be a condition characterized by that gear engagement is performed. One example of this second vehicle conditions is that a first gear just has been engaged after vehicle start off. If it is determined that the vehicle is in at least one second vehicle condition a subsequent method step s430 is performed. If not, the method step 425 is repeated, i.e. it is again determined whether the vehicle is in at least one second vehicle condition or not.
The method step s430 comprises the step of activating the droop function. This step may be performed depending upon whether the vehicle is in a second vehicle condition or not. As depicted above the droop function is a desired function during driving of the vehicle. The droop function provides positive effects during driving situations other than starting off a vehicle carrying a heavy load or when starting off in uphill slope. Thus, the droop function should be activated in an appropriate way, as soon as it does not have a limiting effect on drivability during stating off the vehicle. After the method step s430 the method ends.
With reference to Figure 5, a diagram of one embodiment of the electronic control unit 200 is shown. The electronic control unit 200 is also referred to as apparatus. The apparatus comprises a non-volatile memory 520, a data processing device 510 and a read/write memory 550. Non-volatile memory 520 has a first memory portion 530 wherein a computer program, such as an operating system, is stored for controlling the function of the apparatus. Further, the apparatus comprises a bus controller, a serial communication port, I/O- means, an A/D-converter, a time date entry and transmission unit, an event counter and an interrupt controller (not shown). Non-volatile memory 520 also has a second memory portion 540.
A computer program P comprising routines for improving drivability of a vehicle having a droop function may be stored in an executable manner or in a compressed state in a separate memory 560 and/or in read/write memory 550. The memory 560 is a non-volatile memory, such as a flash memory, an EPROM, an EEPROM or a ROM. The memory 560 is a computer program product. The memory 550 is a computer program product.
When it is stated that the data processing device 510 performs a certain function it should be understood that the data processing device 510 performs a certain part of the program which is stored in the separate memory 560, or a certain part of the program which is stored in the read/write memory 550.
The data processing device 510 may communicate with a data communications port 599 by means of a data bus 515. The non-volatile memory 520 is adapted for communication with the data processing device 510 via a data bus 512. The separate memory 560 is adapted for communication with the data processing device 510 via a data bus 511. The read/write memory 550 is adapted for communication with the data processing device 510 via a data bus 514.
Data relevant for determining a first and second vehicle state are stored in the memory 550 or 560 of the ECU. Also predetermined first and second vehicle condition data are stored in the memory 550 or 560 of the ECU, which data may be used for determining whether the vehicle is in a first or second vehicle condition.
When data, such as vehicle speed relative ground or gearbox position status, is received on the data port 599 from e.g. a vehicle speed sensor or the transmission control unit, it is temporarily stored in the second memory portion 540. When the received input data has been temporarily stored, the data processing device 510 is set up to perform execution of code in a manner described above. The processing device 510 is arranged to deactivate or activate the droop function depending upon if the vehicle is in a first or second vehicle condition. The processing device 510 is arranged to activate the droop function in a successive manner during a predetermined phase of the activation step. For example, the processing device 510 is arranged to activate the droop function in a successive manner during a phase corresponding to the clutch pedal moving the last 5% back up to an initial position thereof. These last 5% correspond to a process of bringing the clutch of the vehicle into full engagement. Of course the phase may correspond to the clutch pedal moving more or less than last 5% back up to an initial position thereof.
Parts of the methods described herein can be performed by the apparatus by means of the data processing device 510 running the program stored in the separate memory 560 or the read/write memory 550. When the apparatus runs the program, parts of the methods described herein are executed.
According to an aspect of the invention the apparatus is arranged to run a computer program, comprising computer readable means for causing the electronic control unit or another computer connected to the electronic control unit to perform the steps of:
- deactivating said droop function in at least one predetermined first vehicle condition; and
- activating said droop function in at an at least one predetermined second vehicle condition.
The invention also relates to a computer program product comprising a computer program for improving drivability of a vehicle having a droop function and a computer readable medium on which the computer program is stored. The invention also relates to a computer, such as an embedded electronic control unit or a vehicle external computer comprising a storing means, and a computer program for improving drivability of a vehicle having a droop function, stored in the storing means.
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