WO2009008816A1

WO2009008816A1 - Atv with electronic throttle control

Info

Publication number: WO2009008816A1
Application number: PCT/SE2008/050821
Authority: WO
Inventors: Lars Andersson; Mats Malmberg
Original assignee: Husqvarna Ab
Priority date: 2007-07-11
Filing date: 2008-07-02
Publication date: 2009-01-15

Abstract

A four-wheeled ATV, of the kind preferably having its two rear wheels always driven at the same speed, comprising: a) an engine (20) with an intake system (21) having at least one electrically operated throttle valve which can move from a closed position to a fully opened position, b) a manually operated electronic throttle actuator (5) being able to provide throttle actuator signals (TAS) in the range from zero throttle to full throttle, c) a gear box (40) comprising a at least two forward gear positions, a neutral gear position and at least one reverse gear position, d) an Engine Control Unit (10) for controlling the at least one electrically operated throttle valve, which Engine Control Unit (10) can be set in at least two driving modes, one of them being a terrain mode, and where the Engine Control Unit (10) is arranged to determine a control signal (CS), for controlling the throttle position (TP) of the electrically operated throttle valve, based on received throttle actuator signals (TAS) from the manually operated electronic throttle actuator (5), the set driving mode and received sensor inputs including the current throttle position of the electrically operated throttle valve and the current gear position of the engine transmission.

Description

ATV WITH ELECTRONIC THROTTLE CONTROL

DESCRIPTION

TECHNICAL FIELD

The present invention relates to a four-wheeled ATV, of the kind preferably having its two rear wheels always driven at the same speed, in particular to the control of the throttle valves thereof.

BACKGROUND

Recently, in for example motorcycles or cars, different kinds of electronic throttle control has been implemented were e.g. a an electronic motor is coupled to throttle valves via e.g. a link mechanism and where the gas pedal of a car or the throttle grip of a motor cycle yields an electronic signal which controls the opening and closing of the throttle valves.

However, four wheeled ATVs, also known as quad bikes, are still commonly equipped with thumb throttles which are mechanically coupled to the throttle valves through a throttle cable, where the throttle valves opens and closes mechanically as the thumb throttle is actuated.

The invention concerns an ATV which uses electronic throttle control and aims to solve several problems for ATVs using mechanical throttle. Since the use of ATVs and their construction differs from motorcycles and vehicles; the demands on an electronic throttle system for an ATV are different in many aspects.

For instance ATVs are used in a wide variety of environments; they can be driven on roads but also in demanding terrains such as off-road in a forest. It would hence be desirable if the ATV would be able to adapt to such varying conditions and behave safely. For instance in a bumpy terrain the bumpiness may transfer to the throttle input which could lead to a unwanted engine fluctuations. Further if the engine is too strong on lower gears the ATV may flip around if the throttle is actuated to fast, which of course is undesirable.

Regarding an ATV using centrifugal clutch, where the engine idle speed at both high and low gear are low enough for the centrifugal clutch to not be engaged, i.e. no drive on the wheels, the ATV may be believed to be in neutral or parking gear since the ATV is not moving. If someone would unintentionally press the thumb actuator the ATV might drive off. It would be advantageous to avoid this problem or alternatively minimise the consequences thereof.

SUMMARY OF THE INVENTION

The purpose of the subject invention is to considerably reduce the problems outlined above by providing a four-wheeled ATV, of the kind having its two rear wheels always driven at the same speed, comprising: a) an engine with an intake system having at least one electrically operated throttle valve which can move from a closed position to a fully opened position, b) a manually operated electronic throttle actuator being able to provide throttle actuator signals in the range from zero throttle to full throttle, c) a gear box comprising a at least two forward gear positions, a neutral gear position and at least one reverse gear position, d) an Engine Control Unit for controlling the at least one electrically operated throttle valve, which Engine Control Unit can be set in at least two driving modes, one of them being a terrain mode, and where the Engine Control Unit is arranged to determine a control signal, for controlling the throttle position of the electrically operated throttle valve, based on received throttle actuator signals from the manually operated electronic throttle actuator, the set driving mode and received sensor inputs including the current throttle position of the electrically operated throttle valve and the current gear position of the engine transmission.

Preferably in at least the terrain mode of the driving modes, the Engine Control Unit includes filtering functions for smoothing received throttle actuator signals from the manually operated electronic throttle actuator, while determining the control signals to the electrically operated throttle valve, in order to reduce the effect of a unwanted fluctuation of the throttle actuator signals due to bumpy terrain. A smoothing operation could e.g. be based on a moving average algorithm.

Further in at least the terrain mode of the driving modes; the Engine Control Unit preferably includes functions for discarding positive as well as negative spikes in the throttle actuator signals from the throttle actuator, while determining the control signals to the electrically operated throttle valve, by judging if the spikes are larger than a predetermined first threshold and persistent only during a short time period being lower than a second threshold.

Further it preferred that for the at least two forward gear positions, the control signals are determined so that the resulting throttle position at lower gears is dampened with regards to the throttle actuator signals, so that a full throttle input from the throttle actuator provides for a decreasingly maximal opening position of the throttle valve, the lower the gears. Preferably the throttle position is dampened by a constant dampening factor being less than 1.

It is also preferred that for the at least one reverse gear, the control signals are determined so that the resulting throttle position is dampened with regards to the throttle actuator signals.

According to a further embodiment of the present invention the ATV further comprises a trigger button which when non-actuated keeps the throttle actuator inactive thereby limiting the engine throttle to idle throttle and when actuated activates the throttle actuator to be able to adjust the engine throttle between idle throttle and full throttle. The embodiment may also be suitable for other vehicles than ATVs, for instance snow mobiles, water jets, or other vehicles using hand controlled throttle control. Such a trigger button prevents the throttle actuator to be accidently actuated.

Preferably the throttle actuator is thumb throttle actuator.

The throttle actuator is preferably an electronic throttle actuator connected to an electrically controlled throttle valve, i.e. drive-by- wire. Alternatively the throttle actuator is mechanically connected to the throttle valve, mechanically controlling the throttle valve.

Preferably the trigger button and the throttle actuator are both located at a first handlebar grip of the handlebar, preferably in such manner that a single hand can actuate both the trigger button and the throttle actuator. Thereby the throttle of the ATV can be easily controlled.

Alternatively the trigger button and the throttle actuator are located at a respective opposite handlebar grip of the handlebar, so that both hands are required on the handle bar to drive the ATV.

Alternatively two trigger buttons are provided, one at each handlebar grip respectively, and where both trigger buttons needs to be actuated to activate the throttle actuator.

Alternatively, each handle bar grip includes throttle actuator with a corresponding trigger button, so that the throttle of the ATV can be easily controlled using one hand regardless if the driver is left or right handed.

It is further preferred that the trigger button is located on an upper side of the handlebar grip. This enables the driver to easily actuate the trigger button.

If the trigger button is located at close to the throttle actuator the trigger button can mechanically interlock the throttle actuator, which interlock is released when the trigger button is actuated thereby allowing the throttle actuator to be actuated.

Alternatively the trigger button is an electronic trigger button, electrically deactivating respectively activating the electronic throttle actuator in such manner that the trigger button is required to be actuated for the electronic throttle actuator to control the electronic throttle valve. For instance by having the trigger button connected to the Electronic

Control Unit (ECU), which trigger button provides a signal to the ECU when the trigger button is actuated keeping the electronic throttle actuator active and thereby allowing it to control the throttle of the ATV. BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in more detail with reference to preferred embodiments and the appended drawings. FIG. 1 shows a perspective view of an ATV according to the present invention,

FIG. 2 shows a zooming A of FIG. 1,

FIG. 3 shows a schematic picture over the transmission of an ATV according to the present invention,

FIG. 4 is a diagram showing the effect of a smoothing algorithm, FIG. 5 is a diagram showing the effect of a spike removing algorithm,

FIG. 6 shows a number of examples of linear mappings between the actual actuation of a thumb throttle and the opening of the throttle valves,

FIG. 7 shows a number of examples of non-linear mappings between the actual actuation of a thumb throttle and the opening of the throttle valves, FIG. 8 shows a zooming of FIG. 1 but where the grip of the handlebar comprises a trigger button according to a further embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The ATV 1 shown in FIG. 1-2 has a handlebar 2a, 2b for turning its front wheels 3. A throttle actuator in the form of a thumb throttle 5 is located at the end of the right hand handlebar 2b, i.e. the right hand grip. The thumb throttle 5 is digitally connected to an Engine Control Unit 10 (see FIG. 3). A first brake actuator 6a is arranged at the end of the left hand handlebar 2a, i.e. at the left hand grip, and a second brake actuator 6b is arranged at the end of the right hand handlebar 2b. The brake actuators 6a, 6b are either connected mechanically to the front and rear wheels 3, 4 respectively via e.g. a Bowden cable or digitally. A mode switch 7 is also located at the end of the right hand handlebar 2b. The mode switch 7 is connected to the Engine Control Unit 10 (see FIG. 3) and can be set in different driving modes such as e.g. sport mode, road mode, terrain mode. It could also have a learner mode, e.g. for new drivers. In this mode the power of the engine, e.g. by a reduced maximum throttle position, and/or the opening speed of the throttle could be reduced. This would give a high power vehicle a more forgiving character. At the left side of the ATV 1 is provided a F/R shifting lever 8 for shifting between forward and reverse drive and at the right side a gear shifting lever 8 for shifting between gears, e.g. between high gear, low gear, neutral and parking. The F/R shifting lever 8 and the gear shifting lever 9 are preferably mechanically connected to the gear box 13 (see FIG. 3), where sensors provides information to the Engine Control Unit 10 regarding which gear is chosen by the gear shifting lever 9 as well as if the ATV 1 is set to reverse or forward drive by the F/R shifting lever F/R.

FIG. 3 shows a schematic view of the transmission of the ATV. The engine 20, e.g. s two cylinder V-twin internal combustion engine, has an intake system 21 including one electrically operated throttle valve per cylinder of the engine, which electrically operated throttle valve is controlled by the Engine Control Unit 10 via control signals CS. The shown ATV uses Continuously Variable Transmission which is indicated by the box labelled 30 following the engine 20. A manually operated gearbox 40 follows the Continuously Variable Transmission 30, where the gear shifting lever 9 can shift the gears between high gear, low gear, neutral and parking. The chosen gear position is detected by a sensor and sent to the Engine Control Unit 10 as indicated by the dotted line GEAR. The gearbox 40 can also be set to forward or reverse drive via the F/R shifting lever 8. It should be noted that the ATV has high and low gear in both directions (forwards respectively reverse). The chosen F/R position is detected by a sensor and sent to the

Engine Control Unit 10 as indicated by the dotted line F/R. The rear wheels 4 have a solid rear axle 50 (i.e. no differential) and are hence driven at the same speed whereas the front wheels 3 utilises a differential 51.

The Engine Control Unit 10 further receives sensor inputs about the engine speed ES before the Continuously Variable Transmission 30 and driving speed DS is detected at a position after the Continuously Variable Transmission 30. Thereby it would the possible to calculate the current gear ratio of the Continuously Variable Transmission 30.

The Engine Control Unit 10 also receives inputs from the mode switch 7 determining which driving mode the engine is set to and actuator signals TAS from the thumb throttle 5 indicating the driver's desired throttle. Based on sensor and actuator inputs the Engine Control Unit 10 determines control signals CS to control the electrically controlled throttle valves of the intake system 21, but also the fuel supply and possibly the ignition timing of the engine 20.

When a driver of the ATV actuates the thumb throttle 5 a digital throttle actuator signal TAS is sent to the Engine Control Unit 10. The actuator signal TAS from the thumb throttle 5 are used as a base by the Engine Control Unit 10 when determining the control signals CS. How the actuator signal TAS from the thumb throttle 5 are transformed to the control signals CS may be dependent of several operating conditions; the chosen driving mode by the mode switch 7, the chosen gear position by the gear shifting lever 9, forward or reverse by the F/R shifting lever 8, measured engine speed ES, measured driving speed DS, as well as inputs from further sensors and/or actuators.

In FIG. 4 it is shown how the actuator signal TAS from the thumb throttle 5 are filtrated by a moving average algorithm, i.e. the actuator signal TAS are smoothed. The squares represent the raw data of the actuator signal TAS, and line is the result from a 5-term moving average algorithm. Such a filter may be suitable in particular when the driving mode is set to terrain, since in a bumpy terrain the driver may have it hard to provide a steady throttle. Of course other smoothing algorithms could also be used.

It is also possible to sort out spikes in the actuator signal TAS as indicted by FIG. 5. The squares represent the raw data of the actuator signal TAS, and line is the result from a spike removing algorithm implemented in the Engine Control Unit 10, where the algorithm discards positive as well as negative spikes in the throttle actuator signals TAS, while determining the control signals CS, by judging if the spikes are larger than a predetermined first threshold and persistent only during a short time period being lower than a second threshold.

FIG 6 and 7 are examples of how the actuator signal TAS can be mapped to provide a corresponding opening of the throttle valve indicated by the throttle position TP. FIG. 6 indicates a linear mapping function whereas FIG. 7 indicates a non linear mapping function.

In FIG. 6 the line labelled 201 shows a 1:1 mapping, i.e. the throttle input from the thumb actuator 5 corresponds to an equal opening (in percent) of the throttle valves. The Engine Control Unit 10 could have such a mapping when the operating conditions are e.g. the mode switch 7 set to sport mode together with the gear shifting lever 9 at high gear and the F/R shifting lever 8 at forward, whereas when the gear shifting lever 9 moves to low gear another mapping is used. Thus each unique combination (operating condition) of the positions of the mode switch 7, the gear shifting lever 9 and the F/R shifting lever 8 could have their own mappings as well as their own filtering algorithms (described above). Each line in FIG. 6, the lines 201, 202, 203, 204, 205 are examples of mappings that could be implemented for a unique operating condition, and the same yields for the lines labelled 301, 302, 303, 304, 305 of FIG. 7 with the difference that they show examples of non linear mapping s .

In for instance operating condition the mode switch 7 set to road mode together with the gear shifting lever 9 at low gear and the F/R shifting lever 8 at reverse, a mapping such as the mapping indicated by the line 205 or the line 305 could be feasible, i.e. a comparably large reduction of performance. The vehicle speed could also be limited in reverse mode by comparing the vehicle speed VS to a speed threshold, e.g. 8 km/h at low gear reverse and 15 km/h at high gear reverse. I the threshold is exceeded the throttle valves closes somewhat to reduce the vehicle speed VS.

In FIG. 8 the ATV is shown, according to an embodiment of the present invention, with a trigger button 11 at the grip of the right hand handlebar 2b, preferably at an upper part thereof. The trigger button 11 is required to be actuated in order to activate the thumb throttle 5. This could be accomplished by having a mechanical interlock between the thumb throttle 5 and the trigger button 11, which locks the thumb throttle 5 in a non actuated state as long as the trigger button 11 also is non actuated, and which interlock is released when the trigger button 11 is actuated thereby enabling the thumb throttle 5 to be actuated. Alternatively the interlock by the trigger button 11 could be electronic where the Electronic Control Unit 10 receives a signal whenever the trigger button 11 is actuated and which signal is required by the Electronic Control Unit 10 to adjust the throttle above idle throttle.

The trigger button could, if electronically implemented, be placed apart from the thumb throttle 5, for instance at the opposite grip of the left hand handlebar 2a. It would then also be possible having two trigger buttons 11, one at each grip of the handlebar 2a, 2b where it could be required that either one or both trigger buttons 11 should be actuated to unlock the thumb throttle 5. Further, it would also be possible to have trigger buttons 11 elsewhere, for instance where the feet normally are placed when driving.

A trigger button 11 could in particular be useful if the ATV has a centrifugal clutch, i.e. when the engine is idling there is no drive on the wheels regardless which gear is used. This would prevent the ATV from start moving if the thumb throttle 5 is actuated without the intention of doing so, when the engine is left running in a low or high gear position.

Whereas the invention has been shown and described in connection with the preferred embodiment thereof it will be understood that many modifications, substitutions, and additions may be made which are within the intended broad scope of the following claims.

Claims

1. A four-wheeled ATV, of the kind preferably having its two rear wheels always driven at the same speed, comprising: a) an engine (20) with an intake system (21) having at least one electrically operated throttle valve which can move from a closed position to a fully opened position, b) a manually operated electronic throttle actuator (5) being able to provide throttle actuator signals (TAS) in the range from zero throttle to full throttle, c) a gear box (40) comprising a at least two forward gear positions, a neutral gear position and at least one reverse gear position, d) an Engine Control Unit (10) for controlling the at least one electrically operated throttle valve, which Engine Control Unit (10) can be set in at least two driving modes, one of them being a terrain mode, and where the

Engine Control Unit (10) is arranged to determine a control signal (CS) , for controlling the throttle position (TP) of the electrically operated throttle valve, based on received throttle actuator signals (TAS) from the manually operated electronic throttle actuator (5), the set driving mode and received sensor inputs including the current throttle position of the electrically operated throttle valve and the current gear position of the engine transmission.

2. An ATV according to claim 1 wherein for at least the terrain mode of the driving modes, the Engine Control Unit (10) includes functions for smoothing received throttle actuator signals (TAS) from the manually operated electronic throttle actuator (5), while determining the control signals (CS) to the electrically operated throttle valve, in order to reduce the effect of a unwanted fluctuation of the throttle actuator signals (TAS) due to bumpy terrain.

3. An ATV according to claim 2 wherein the smoothing operation is based on a moving average algorithm.

4. An ATV according to anyone of claim 1 to 3 wherein in at least the terrain mode of the driving modes; the Engine Control Unit (10) includes functions for discarding positive as well as negative spikes in the throttle actuator signals (TAS) from the throttle actuator (5), while determining the control signals (CS) to the electrically operated throttle valve, by judging if the spikes are larger than a predetermined first threshold and persistent only during a short time period being lower than a second threshold.

5. An ATV according to anyone of claiml to 4 wherein for the at least two forward gears, the control signals (CS) are determined so that the resulting throttle position

(TP) at lower gears is dampened with regards to the throttle actuator signals (TAS), so that a full throttle input from the throttle actuator (5) provides for a decreasingly maximal opening position of the throttle valve, the lower the gears.

6. An ATV according to anyone of claim 5 wherein throttle position (TP) is dampened by a constant dampening factor being less than 1.

7. An ATV according to anyone of claiml to 6 wherein for the at least one reverse gear, the control signals (CS) are determined so that the resulting throttle position (TP) is dampened with regards to the throttle actuator signals (TAS).

8. An ATV according to anyone of claiml to 7 wherein the engine control unit 10 also receive sensor inputs about the vehicle speed, and where the engine control unit 10 includes functions for limiting the maximum speed at the at least one reverse gear.

9. A motor driven vehicle comprising a manually controlled throttle actuator for controlling the engine throttle from idle throttle to full throttle, characterised in that it further comprises a manually controlled trigger button (11) which when non actuated keeps the throttle actuator (5) inactive thereby limiting the engine throttle to idle throttle and when actuated activates the throttle actuator (5) to be able to adjust the engine throttle between idle throttle and full throttle.

10. A motor driven vehicle according to claim 9 wherein the throttle actuator (5) is an electronic throttle actuator, controlling an electrically driven throttle valve through drive-by- wire.

11. A motor driven vehicle according to claim 9 or 10 wherein the vehicle comprises a handlebar (2a, 2b) for steering the vehicle, the throttle actuator (5) and the trigger button (11) both are located at a first handlebar grip of the handlebar (2a, 2b).

12. A motor driven vehicle according to claim 9 or 10 wherein the vehicle comprises a handlebar (2a, 2b) for steering the vehicle, the throttle actuator (5) is located at a first handlebar grip of the handlebar (2a, 2b) and and the trigger button (11) is located at a second opposite handlebar grip of the handlebar (2a, 2b).

13. A motor driven vehicle according to claim 9 or 10 wherein two trigger buttons (11) are provided, one at each handlebar grip respectively, and where both trigger buttons (11) needs to be actuated to activate the throttle actuator (5).

14. A motor driven vehicle according to anyone of claim 9 to 12 wherein the trigger button (11) is located on an upper side of the handlebar grip.

15. A motor driven vehicle according to claim 11 wherein the trigger button when non actuated locks the throttle actuator (5) mechanically through an interlock mechanism thereby preventing actuation of the throttle actuator (5), which interlock is released when the trigger button (11) is actuated enabling the throttle actuator (5) to be actuated.

16. A motor driven vehicle according to anyone of claim 10 to 14 wherein the trigger button (11) is an electronic trigger button, electrically deactivating respectively activating the electronic throttle actuator (5) in such manner that the trigger button

(11) is required to be actuated for the electronic throttle actuator (5) to control the electronic throttle valve.

17. A motor driven vehicle according to anyone of claims 9-16 wherein the throttle actuator (5) is thumb throttle actuator.

18. A motor driven vehicle according to anyone of claims 9-17 wherein the vehicle is a four-wheeled ATV.