Method for accelerating a vehicle from rest

A method for accelerating a vehicle from rest. The method includes receiving a mode indication indicating a launch control mode selected; receiving a brake-on indication; controlling the engine according to a launch control strategy; determining an accelerator position; for an accelerator position greater than zero, controlling the engine to: increase open a throttle valve and control the engine to limit engine torque output; receiving a brake-off indication; controlling the engine according to the standard control strategy, controlling the engine according to the standard control strategy with the braking system having been released causing the vehicle to accelerate from rest, a first rate of acceleration from rest of the vehicle being greater than a second rate of acceleration from rest of the vehicle for corresponding changes in accelerator position, the first rate corresponding to accelerating from rest after controlling the engine according to the standard and launch control strategies.

FIELD OF THE TECHNOLOGY

The present technology relates to controlling an engine of a vehicle, and more specifically to methods for accelerating a vehicle from rest.

BACKGROUND

For vehicles having turbo-charged internal combustion engines, such as those used in snowmobiles and all-terrain vehicles (ATVs), the efficiency of the combustion process can be increased by compressing the air entering the engine. This can be accomplished using a turbocharger connected to the air intake and exhaust systems of the snowmobiles. The compression of the air by the turbocharger may be of particular importance when the internal combustion engine is operated in environments where atmospheric pressure is low or when the air gets thinner, such as when the engine is operated at high altitudes.

When accelerating the vehicle from rest, however, there is a delay in the efficiency boost from the turbocharger due to the time it takes for the turbocharger to run at full capacity (referred to as “spooling-up”). The spooling-up process may even, in some cases, decrease air flow to the engine, slowing the initial acceleration (referred to as “turbo-lag”). In some cases, the turbocharger could be bypassed during initial acceleration in order to avoid turbo-lag, but in such cases any benefit of the turbocharger would be delayed until the turbocharger was eventually spooled-up.

There is thus a need for methods or systems for accelerating from rest for turbo-charged engines that could allow for benefitting from turbocharger boost while overcoming some of the previously known disadvantages of utilizing the turbocharger during initial acceleration.

SUMMARY

According to one aspect of the present technology, there is provided methods and systems for accelerating a turbo-charged vehicle from rest. Specifically, the present embodiment is described in reference to a snowmobile and an ATV. The method includes, upon selection of a “launch control” mode to aid in initial acceleration, increasing engine speed and opening a throttle valve while the vehicle is still at rest. By opening the throttle and increasing the engine speed (revving up the engine), air flow through the engine and also the turbocharger is increased. As such, the turbocharger can spool-up prior to initial acceleration (acceleration from rest) of the vehicle. This allows for faster acceleration from rest, as boost from the turbocharger is available for all of the initial acceleration, with generally no time lost to spooling up and generally without loss of acceleration power from lagging in the turbocharger. In order to avoid the vehicle from prematurely accelerating when the throttle is open, by engaging a transmission and/or overwhelming the brakes for example, engine speed and torque are limited while the engine is idling at increased engine speed and the throttle is open. Engine speed and torque limiting are achieved by causing inefficient ignition which is produced by adjusting the ignition angle to delay combustion ignition in one or more cylinders. Engine speed and torque limiting can additionally or alternatively be achieved by deactivating one or more cylinders by preventing ignition and fuel injection periodically in a given cylinder.

According to an aspect of the present technology, there is provided a method for accelerating a vehicle from rest. The method includes controlling, by a controller, an engine of the vehicle according to a first control strategy; receiving, by the controller, a mode indication indicating that an operator of the vehicle has selected a launch control mode for accelerating the vehicle; receiving, by the controller, a brake-on indication indicating that a braking system of the vehicle has been activated; in response to receiving at least the mode indication and the brake-on indication, controlling the engine, by the controller, according to a second control strategy; while controlling the engine according to the second control strategy, determining, by the controller, an accelerator position of an accelerator of the vehicle; in response to the accelerator position being greater than zero, controlling, by the controller, the engine to: increase, according to the accelerator position, an opening of a throttle valve of the engine, and control operational conditions of the engine to limit engine torque output; while controlling the engine according to the second control strategy, receiving, by the controller, a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine, by the controller, according to the first control strategy, controlling the engine according to the first control strategy with the braking system having been released causing the vehicle to accelerate from rest, a first rate of acceleration from rest of the vehicle being greater than a second rate of acceleration from rest of the vehicle for corresponding changes in accelerator position, the first rate of acceleration corresponding to the vehicle accelerating from rest after sequentially controlling the engine according to the first and second control strategies; the second rate of acceleration corresponding to the vehicle accelerating from rest by controlling the engine according to the first control strategy without previously controlling the engine according to the second control strategy.

In some embodiments, controlling the engine according to the second control strategy includes: increasing a speed of the engine, and limiting a torque output of the engine.

In some embodiments, controlling the engine according to the first control strategy comprises controlling a turbocharged engine of the vehicle according to standard operational parameters.

In some embodiments, the method of further includes determining, by the controller, that a speed of the engine has surpassed a threshold engine speed; and wherein the controller controls the engine according to the second control strategy in response to receiving the mode indication and the brake-on indication, and determining that the engine speed has surpassed a threshold engine speed.

In some embodiments, the method further includes prior to receiving the mode indication, determining, by the controller, that each of a plurality of initial mode conditions have been met; and in response to the plurality of initial mode conditions being met, enabling a mode input by the controller, the mode indication being sent to the controller from the mode input upon selection of the launch control mode by the operator via the mode input.

In some embodiments, the method further includes while controlling the engine according to the second control strategy: determining, by the controller, that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle is operated according to the first control strategy.

In some embodiments, determining that the at least one deactivation condition has been met includes determining that a time limit of controlling the engine according to the second control strategy has been reached.

In some embodiments, the method further includes subsequent to receiving the mode indication and prior to receiving the brake-off indication: determining, by the controller, that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle is operated according to the first control strategy.

In some embodiments, controlling operational conditions of the engine to limit engine torque output comprises at least one of: delaying combustion ignition; and deactivating at least one cylinder.

In some embodiments, in response to increasing the opening of the throttle valve according to the accelerator position, air flow increases through the engine.

In some embodiments, in response to controlling the engine according to the first and second control strategies, a speed of rotation of a turbocharger of the vehicle increases.

In some embodiments, a first speed of rotation of a turbocharger of the vehicle upon acceleration from rest is greater than a second speed of rotation of the turbocharger upon acceleration from rest; the first speed of rotation corresponds to the vehicle accelerating from rest after sequentially controlling the engine according to the first and second control strategies; and the second speed of rotation corresponds to the vehicle accelerating from rest by controlling the engine according to the first control strategy without previously controlling the engine according to the second control strategy.

In some embodiments, in response to receiving the mode indication and prior to controlling the engine according to the second strategy, controlling the engine to increase engine speed.

In some embodiments, the method further includes subsequent to receiving the mode indication and prior to controlling the engine according to the first strategy: determining, by the controller, that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle is operated according to the first control strategy.

In some embodiments, determining that the at least one deactivation condition has been met includes determining that a time limit of increased engine speed has been reached.

According to another aspect of the present technology, there is provided a vehicle including a frame; at least one seat connected to the frame; an engine supported by the frame; a turbocharger operatively connected to the engine; a controller communicatively connected to the engine; and an accelerator communicatively connected to the controller, the controller being configured to perform the method of any of the above embodiments.

According to yet another aspect of the present technology, there is provided a vehicle including a frame; at least two ground engaging members connected to the frame; a braking system operatively connected to at least one of the at least two ground engaging members; at least one seat connected to the frame; an engine supported by the frame; a turbocharger operatively connected to the engine; a controller communicatively connected to the engine; and an accelerator communicatively connected to the controller, the controller being configured to perform the steps of: controlling, by a controller, an engine of the vehicle according to a first control strategy; receiving, by the controller, a mode indication indicating that an operator of the vehicle has selected a launch control mode for accelerating the vehicle; receiving, by the controller, a brake-on indication indicating that a braking system of the vehicle has been activated; in response to receiving the mode indication and the brake-on indication, controlling the engine, by the controller, according to a second control strategy; while controlling the engine according to the second control strategy, determining, by the controller, an accelerator position of an accelerator of the vehicle; in response to the accelerator position being greater than zero, controlling, by the controller, the engine to: increase, according to the accelerator position, an opening of a throttle valve of the engine, and control operational conditions of the engine to limit engine torque output; while controlling the engine according to the second control strategy, receiving, by the controller, a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine, by the controller, according to the first control strategy, controlling the engine according to the first control strategy with the braking system having been released causing the vehicle to accelerate from rest, a first rate of acceleration from rest of the vehicle being greater than a second rate of acceleration from rest of the vehicle for corresponding changes in accelerator position, the first rate of acceleration corresponding to the vehicle accelerating from rest after sequentially controlling the engine according to the first and second control strategies; the second rate of acceleration corresponding to the vehicle accelerating from rest by controlling the engine according to the first control strategy without previously controlling the engine according to the second control strategy.

In some embodiments, the vehicle further includes a mode input communicatively connected to the controller; and wherein the controller is further configured to perform the steps of: prior to receiving the mode indication, determining, by the controller, that each of a plurality of initial mode conditions have been met, and in response to the plurality of initial mode conditions being met, enabling the mode input by the controller to allow the operator to select the launch control mode.

In some embodiments, the vehicle is a snowmobile; the at least two ground engaging elements include: two skis connected to the frame, and an endless track disposed rearward of the two skis; the at least one seat is at least one straddle-seat; and the accelerator is an accelerator lever.

In some embodiments, the vehicle is an all-terrain vehicle (ATV); the at least two ground engaging elements include at least two wheels; the at least one seat is at least one straddle-seat; and the accelerator is an accelerator lever.

According to yet another aspect of the present technology, there is provided a method for accelerating a vehicle from rest. The method includes controlling, by a controller, an engine of the vehicle, the engine having a first mode and a second mode: the first mode controlling the engine speed from a first idle speed to a first maximum engine speed with respect to a corresponding idle accelerator position and a maximum accelerator position; the second mode controlling the engine speed from a second idle speed to a second maximum engine speed with respect to the corresponding idle acceleration position and the maximum acceleration position, the second maximum engine speed being less than the first maximum engine speed, receiving, by the controller, a mode indication indicating that an operator of the vehicle has selected a launch control mode for accelerating the vehicle; receiving, by the controller, a brake-on indication indicating that a braking system of the vehicle has been activated; in response to receiving the mode indication and the brake-on indication, controlling the engine, by the controller, according to the second mode; while controlling the engine according to the second mode, receiving, by the controller, a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine, by the controller, according to the first mode, controlling the engine according to the first mode with the braking system having been released causing the vehicle to accelerate from rest.

For purposes of this application, terms related to spatial orientation such as forwardly, rearward, upwardly, downwardly, left, and right, are as they would normally be understood by an operator of a vehicle sitting thereon in a normal riding position. Terms related to spatial orientation when describing or referring to components or sub-assemblies of the vehicle, separately from the vehicle, should be understood as they would be understood when these components or sub-assemblies are mounted to the vehicle, unless specified otherwise in this application.

Embodiments of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein. The explanations provided above regarding the above terms take precedence over explanations of these terms that may be found in any one of the documents incorporated herein by reference.

It should be noted that the Figures may not be drawn to scale, except where otherwise noted.

DETAILED DESCRIPTION

The present technology is described herein with respect to a snowmobile10having an internal combustion engine and two skis, and further with respect to an all-terrain vehicle (ATV) with an internal combustion engine and four wheels. However, it is contemplated that some aspects of the present technology may apply to other types of vehicles such as, but not limited to, snowmobiles with a single ski, road vehicles having two, three, or four wheels, off-road vehicles, all-terrain vehicles with more or fewer wheels, and side-by-side vehicles.

With reference toFIGS.1and2, a snowmobile10according to the present technology will be described. The snowmobile10includes a forward end12and a rearward end14. The snowmobile10includes a vehicle body in the form of a frame or chassis16which includes a tunnel18, an engine cradle portion20, a front suspension module22and an upper structure24.

An internal combustion engine26is carried in an engine compartment defined in part by the engine cradle portion20of the frame16. A fuel tank28, supported above the tunnel18, supplies fuel to the engine26for its operation. The engine26receives air from an air intake system100. The engine26and the air intake system100are described in more detail below.

An endless drive track30is positioned at the rear end14of the snowmobile10. The drive track30is disposed generally under the tunnel18, and is operatively connected to the engine26through a continuously variable transmission (CVT)128(shown schematically). The endless drive track30is driven to run about a rear suspension assembly32operatively connected to the tunnel18for propulsion of the snowmobile10. The endless drive track30has a plurality of lugs31extending from an outer surface thereof to provide traction to the track30.

The rear suspension assembly32includes drive sprockets34, idler wheels36and a pair of slide rails38in sliding contact with the endless drive track30. The drive sprockets34are mounted on an axle35and define a sprocket axis34a.The axle35is operatively connected to a crankshaft126(FIG.3) of the engine26via the CVT128. The slide rails38are attached to the tunnel18by front and rear suspension arms40and shock absorbers42. It is contemplated that the snowmobile10could be provided with a different version of a rear suspension assembly than the one shown herein.

At the rear end of the snowmobile10, a snow flap94extends downward from the rear end of the tunnel18. The snow flap94protects against dirt and snow that can be projected upward from the drive track30when the snowmobile10is being propelled by the moving drive track30. It is contemplated that the snow flap94could be omitted.

A straddle seat60for receiving an operator of the snowmobile10is positioned atop the fuel tank28. A fuel tank filler opening covered by a cap92is disposed on the upper surface of the fuel tank28in front of the seat60. It is contemplated that the fuel tank filler opening could be disposed elsewhere on the fuel tank28. The seat60is adapted to accommodate the operator, also referred to as a driver, of the snowmobile10. The seat60could also be configured to accommodate a passenger. A footrest64is positioned on each side of the snowmobile10below the seat60to accommodate the driver's feet.

The snowmobile10includes an ignition key base65mounted to the snowmobile10forward of the seat60. It is contemplated that parts of the base65could be integral with the top surface of the snowmobile10. The base65is adapted to receive an ignition key67(illustrated as engaged with the base65inFIG.1). The key67serves, at least in part, as an anti-theft system as the snowmobile10is prevented from starting when the ignition key67is not engaged with the base65. In cases where the snowmobile10is to be operated by a less experienced operator, by a riding student or a renter for example, the key67could be replaced with a learner key (not shown) which would limit certain operational characteristics. For example, the learner key could limit aspects including, but not limited to: snowmobile top speed and acceleration. In some embodiments, the key67could be equipped with a security system such as, for example, Bombardier Recreational Product's Digitally Encoded Security System (DESS™). It is also contemplated that different anti-theft and/or security systems could be implemented by the snowmobile10and/or the key67.

At the front end12of the snowmobile10, fairings66enclose the engine26and the CVT128, thereby providing an external shell that not only protects the engine26and the CVT128, but can also make the snowmobile10more aesthetically pleasing. The fairings66include a hood68and one or more side panels which can be opened to allow access to the engine26. A windshield69connected to the fairings66acts as a wind screen to lessen the force of the air on the rider while the snowmobile10is moving. It is contemplated that the windshield69could be connected directly to a handlebar84.

Two skis70positioned at the forward end12of the snowmobile10are attached to the front suspension module22of the frame16through a front suspension assembly72. The front suspension module22is connected to the front end of the engine cradle portion20. The front suspension assembly72includes ski legs74, supporting arms76and ball joints (not shown) for operatively connecting to the respective ski leg74, supporting arms76and a steering column82(schematically illustrated).

A steering assembly80, including the steering column82and a handlebar84, is provided generally forward of the seat60. The steering column82is rotatably connected to the frame16. The lower end of the steering column82is connected to the ski legs74via steering rods (not shown). The handlebar84is attached to the upper end of the steering column82. The handlebar84is positioned in front of the seat60. The handlebar84is used to rotate the steering column82, and thereby the skis70, in order to steer the snowmobile10. An accelerator lever86(also referred to as an accelerator, throttle lever, or throttle operator) in the form of a thumb-actuated lever is mounted to the right side of the handlebar84. Other types of accelerator or throttle operators, such as a finger-actuated throttle lever and a twist grip, are also contemplated. A brake actuator88, in the form of a hand brake lever88, is provided on the left side of the handlebar84for controlling a braking system89of the snowmobile10(shown schematically inFIG.1). In the case of implementation of the present methods or systems with different vehicles, for example all-terrain vehicles (ATVs) and/or side-by-side vehicles (SSVs), it is contemplated that the brake actuator could be in the form of a foot-actuated brake (i.e. a brake pedal).

A mode input184, specifically a mode selection button184, is disposed in a display cluster185forward of the handlebar84. In some embodiments, it is contemplated that the button184could be mounted to the left side of the handlebar84. By pressing on the mode selection button184, the operator can choose between different driving modes of the snowmobile10, in the present embodiment, between sport, standard, and economy modes. Additional or alternative modes are also contemplated. As will be described in more detail below, a launch control mode can also be chosen via the mode selection button184to aid in accelerating the snowmobile10from rest. The launch control mode is selected by first selecting the sport mode by repeatedly pushing the mode selection button until the sport mode has been selected, and then holding the button184down until the launch control mode has been further selected. It is contemplated that the mode input184could be implemented in different manners, including for example via a touch screen or a dial. It is also contemplated that the snowmobile10could include a mode input button dedicated for selecting the launch control mode. It is further contemplated that the launch control mode could be a default setting as part of the sport mode. In some non-limiting embodiments, the launch control mode could instead be selected without first selecting sport mode.

The snowmobile10includes other components such as an interactive touch screen and the like. In some embodiments, selection of the different drive modes and the launch control mode described further below, could be done using the interactive touch screen or a handlebar mounted button in some embodiments.

With additional reference toFIGS.3and4A, the engine26and the air intake system100will be described in more detail. Air from the atmosphere flows through side apertures93defined in an upper portion25of the upper structure24of the chassis16(FIG.2). The air then flows into a secondary airbox110. The secondary airbox110is disposed above the front suspension module22. A conduit117(FIG.3) fluidly connects the secondary airbox110to a turbocharger170, specifically to an inlet173of an air compressor172(FIG.3) of the turbocharger170disposed on the front side of the engine26. It is contemplated that the secondary airbox110could be omitted and that air from the atmosphere could directly enter into the inlet173without going through the secondary airbox110.

Air from the atmosphere, passing through the secondary airbox110and into the air compressor172via the conduit117and inlet173, is compressed by the air compressor172. The compressed air then flows out of the air compressor172through an outlet174, into a conduit115and into an intercooler113. The intercooler113is fluidly connected to a primary airbox120via the conduit118(FIG.2) which is in turn connected to the engine26via air outlets123of the primary airbox120. The primary airbox120includes an intake air temperature sensor121(shown schematically inFIG.4A) for measuring the temperature of air flowing into the engine26. In some embodiments, the airbox120could additionally or alternatively include an air pressure sensor.

With additional reference toFIG.4B, the engine26and the turbocharger170are described in further detail. The engine26is an inline, three-cylinder, four-stroke, internal combustion engine. The cylinders of the engine26are oriented with their cylindrical axes disposed vertically. It is contemplated that the engine26could be configured differently. For example, the engine26could have more or fewer cylinders, and the cylinders could be arranged in a V-configuration instead of in-line. It is contemplated that in some embodiments the engine26could be a two-stroke internal combustion engine, a carbureted engine, or any other suitable engine capable of propelling the snowmobile10.

The snowmobile10includes an engine control unit (ECU)155, shown inFIG.4Band schematically inFIG.4A, for communicating with and controlling the engine26. The ECU155includes at least a non-transitory computer readable medium (not shown) and a processor (not shown). The processor of the ECU155is configured to perform a number of operations including speed and torque limiting operations described below with respect to methods for accelerating the snowmobile10from rest. It is contemplated that the functions of the ECU155could be split between multiple ECUs.

An engine speed sensor157and an engine temperature sensor159(shown schematically) are disposed in the engine26. The engine speed sensor157senses the rotational speed (RPM) of the engine26. The engine temperature sensor159measures the temperature of engine coolant of the engine26. The engine sensors157,159are communicatively connected to the ECU155. In some embodiments, the engine sensors157,159could be implemented as a unified engine sensing unit. It is contemplated that additional or alternative sensors could be used to monitor the engine26.

As shown inFIGS.1,2, and4A, the engine26receives air from the air intake system100, specifically from the primary airbox120, via engine air inlets27defined in the rear portion of each cylinder of the engine26. Each air inlet27is connected to a single throttle body37of the air intake system100; a throttle system assembly137is illustrated in isolation inFIG.4B. The throttle body37has a throttle valve39which rotates to regulate the amount of air flowing through the throttle body37into the corresponding cylinder of the engine26. A throttle valve actuator139is operatively connected to the throttle valve39to change the position of the throttle valve39and thereby adjust the opening of the throttle valve39with operation of the accelerator lever86on the handlebar84. The accelerator lever86is movable between a 0% position (where the throttle valve39is closed), a 100% position (where the throttle valve39is at its most open position), as well as to a plurality of positions between the 0% and the 100% positions (where the throttle valve39is partially opened to a position based at least in part on the lever position).

In the present embodiment, the throttle system assembly137is a hybrid mechanical cable and drive-by-wire system (seeFIG.4B), although this is simply one non-limiting embodiment. The position and the movement of the throttle valve39is monitored by a throttle valve position sensor187operatively connected to the throttle valve39. The actuator139changes the position of the throttle valve39based on input signals received from an electronic control module189which in turn receives inputs signals from a position sensor183associated with the accelerator lever86on the handlebars84.

The engine26receives fuel from the fuel tank28via injectors41shown in at leastFIG.4A. The fuel-air mixture in each of the cylinders of the engine26is ignited by an ignition system including spark plugs43(best seen inFIG.4A). Engine output power, torque and engine speed are determined in part by throttle opening and in part by the ignition timing, and also by various characteristics of the fuel-air mixture such as its composition, temperature, pressure and the like. Control of engine ignition will be described in more detail below.

Exhaust gases resulting from the combustion events in the cylinders are expelled from the engine26via an exhaust system99. An exhaust outlet29is defined in the front portion of each cylinder of the engine26, each cylinder has an exhaust outlet29and an exhaust valve129. The exhaust outlets29are fluidly connected to an exhaust manifold33which is fluidly connected to the turbocharger170.

The turbocharger170is operatively connected to the engine26as is mentioned above. The turbocharger170compresses air and feeds it to the engine26. The turbocharger170includes the air compressor172and an exhaust turbine176(FIG.3). The air compressor172includes a compressor wheel174and is part of the air intake system100(described above). Intake air flowing past the rotating compressor wheel172is compressed thereby. The rotation of the compressor wheel172is powered by a turbine wheel of the exhaust turbine176. The turbine wheel is rotated by exhaust gases expelled from the engine26and directed to flow over the blades of the turbine wheel.

The exhaust system99further includes a muffler97for removing exhaust gas from the snowmobile10. The muffler97is fluidly connected to the turbocharger170, specifically an outlet of the compressor, by an exhaust collector95(FIG.3). It is contemplated that different arrangements could be employed to connect the muffler97to the exhaust collector95.

As is illustrated schematically inFIG.4A, the snowmobile10further includes a controller150. The controller150includes at least a non-transitory computer readable medium (not shown) and a processor (not shown). The processor of the controller150is configured to perform a number of operations including methods described below for accelerating the snowmobile10from rest (the above mentioned launch control mode). It is contemplated that the functions of the controller150could be split between multiple controllers. It is also contemplated that the ECU155could perform the processes and methods of the controller150of the embodiments described herein, and in such cases the controller150could be excluded.

The controller150is operatively connected to the engine control unit (ECU)155of the snowmobile10(shown schematically). The ECU155is in turn operatively connected to the engine26, such that the controller150can monitor and control engine operations via the ECU155. It is contemplated that the controller150operations described herein could be performed by the ECU155in some embodiments. As is mentioned above, the ECU155is communicatively connected to the engine sensors157,159for receiving information therefrom with respect to engine speed and temperature respectively. The controller150is thus connected to the engine sensors157,159via the ECU155. It is contemplated that the controller150could be communicatively connected to alternative and/or additional sensors via the ECU155in some embodiments. The controller150and the ECU155are also communicatively connected to the mode input button184, in order to control the engine26and the snowmobile10according to the mode selected by the operator.

The controller150is further operatively and communicatively connected to the intake air temperature sensor121for monitoring the temperature of air entering the engine26and the throttle valve position sensor187for determining the position of the throttle valve39, a rate of opening of the throttle valve39, the actuator position sensor183, or both. The controller150is further communicatively connected to the accelerator lever position sensor183for sensing the accelerator lever position. The controller150is also communicatively connected to the brake lever88and the braking system89for sensing brake activation status of the braking system89.

Depending on the embodiment, the controller150could be connected to various alternative and/or additional sensors for monitoring components or characteristics of the engine26and/or the snowmobile10. For example, the controller150could be communicatively connected to an exhaust pipe temperature sensor to monitor the temperature of an exhaust pipe and/or the temperature of exhaust exiting the engine26.

Accelerating the snowmobile10from rest, using an operating mode referred to herein as the launch control mode, in accordance with non-limiting embodiments of the present technology will now be described in more detail with reference toFIGS.5and6. An overview of steps taken by the operator and operations performed by the controller150and/or the snowmobile10according to the launch control mode is illustrated by a flowchart200presented inFIG.5.

The controller150first determines if the selection of launch control mode should be made available to the operator of the snowmobile10at operation210. The determination is made by the controller150by confirming that one or more activation conditions, also referred to as initial mode conditions, have been met. Confirmation by the controller150that the activation conditions have been met is done at least upon ignition of the snowmobile10, as well as in response to the snowmobile10subsequently coming to rest. The controller150further verifies that activation conditions have been met at regular spaced intervals, for example every 10 milliseconds, while the snowmobile10is running. In some embodiments, the regularly spaced time intervals could be greater or lesser than 10 ms. It is also contemplated that the controller150could verify the activation conditions in response to the snowmobile10is put into sport mode or another selected mode.

The activation conditions to be met in order to make the launch control mode available for the operator to activate include the following conditions, but in different embodiments the controller150may consider only some of these or additional and/or alternative conditions. First, the snowmobile10should be in a forward gear, with the engine26running. The snowmobile10should be in the sport mode, as chosen through the mode input button184. The snowmobile10should have a speed of 0 km/h (0 mph), such that the snowmobile10is at rest. The speed of the snowmobile10is determined by a speed sensor (not shown). The temperature of the engine26, as determined by the engine temperature sensor159, should be between a minimum and a maximum mode-acceptable engine temperature. The temperature of intake air entering the engine26, as determined by the intake air temperature sensor121, should also be between a minimum and a maximum mode-acceptable air temperature. The exact minimum and maximum temperatures are stored to computer-implemented storage connected to the controller150, although it is contemplated that the minimum and maximum engine temperatures could be calculated by the controller150directly. The controller150also determines that the key67connected to the snowmobile10is a key programmed to allow the launch control mode, e.g. is not a learner key. The accelerator lever position should be at 0%, where the operator has not applied any throttle and the snowmobile10is idling. Further, a maximum number of previous launch control mode starts, for a predetermined time period, should not have been surpassed. In some embodiments, for instance, there may be a limit on the number of times acceleration from rest using the launch control mode may be permitted for a particular time frame of the snowmobile10, and the next acceleration from rest using the launch control mode may not be allowed until the snowmobile10has first been shut down.

As part of the activation or initial mode conditions, the controller150also determines that the snowmobile10has no pre-determined unacceptable faults. Specifically, while one or more faults or errors in components of snowmobile10may be sensed and/or identified by the controller150during determination of the activation conditions, it is contemplated that some “faults” detected may be acceptable and should not impede implementation of the launch control mode. There are some faults, however, that are determined to be incompatible with implementation of the launch control mode and thus are labeled “unacceptable”. As one non-limiting example of such an unacceptable fault, the controller150may not make the launch control mode available if it is determined that the position sensor183for sensing the position of the accelerator lever186is dysfunctional or not communicating with the controller150. As one other non-limiting example of such an unacceptable fault, the controller150may not make the launch control mode available if it is determined that the valve position sensor187is dysfunctional or not communicating with the controller150.

If the activation conditions (initial mode conditions) are met, the controller150enables the mode input184to allow the operator to select the launch control mode at operation220.

In response to the operator selecting the launch control mode via the mode input184, the controller150activates (or “arms”) the launch control mode to control the snowmobile10in operation230. Prior to selection of the launch control mode, the snowmobile10and the engine26are controlled according to a standard control strategy. Control strategies generally vary between different embodiments of the engine26and a person skilled in the art would understand adaptations necessary for a particular embodiment. For example, one such strategy could include sensing a throttle lever angle, determining a torque request based on this lever angle, and controlling a throttle valve opening, fuel injection amount and ignition timing to achieve the requested torque. Control strategies are generally performed within a repeating loop. Once the operator has chosen the launch control mode, the controller150controls the snowmobile10and the engine26according to a launch control strategy, different from the standard control strategy, which provides instructions for the following operations.

The controller150, in conjunction with the ECU155, causes the engine26to increase engine speed (increase idle) in response to the selection of the launch control mode. The idle speed is increased up to a maximum of about 1800 RPM, although it is contemplated that the maximum idle speed could vary. The idle increase serves as an auditory indication to the operator that the launch control mode has been activated. In some embodiments, the controller150/ECU155may not increase the engine speed (idle). In some embodiments, a different auditory indication could be included, for example a tone being played when the launch control mode is selected.

In response to the operator subsequently activating the braking system89via the brake lever88, the controller150then applies an engine speed limit to the engine26of approximately 3200 RPM at operation240. If the operator has previously activated the braking system89, the controller150could perform the operation240immediately following completion of operation230. The exact speed to which the engine26is limited could vary, depending on the particular embodiment of the engine26for example, but the speed is generally chosen to be less than an engagement speed of the CVT128to prevent forward movement of the snowmobile10. In the present embodiment, the engagement speed of the CVT128is approximately 3500 RPM, but this could vary depending in different embodiments of snowmobiles, engines, and/or CVTs.

If, subsequent to applying the engine speed limit of approximately 3200 RPM at operation240and prior to completing any subsequent operations, the controller150determines that the braking system89has been deactivated, the engine speed is decreased to its previous high idle speed (up to 1800 RPM) if the engine speed had subsequently increased, and the engine speed limit previously applied is removed. The launch control mode remains active, and the controller150once again applies the engine speed limit in response to the operator subsequently activating the braking system89.

In response to the operator moving the accelerator lever86to a greater than 0% position, the controller150then causes the throttle valve39to open according to the accelerator lever86position at operation250, and the standard control strategy is followed until the engine speed approximately reaches the applied engine speed limit. Once the engine speed reaches the applied engine speed limit, the controller150controls the throttle valve position, fuel injection and ignition timing by the launch control strategy that limits the torque produced which prevents the engine speed from going beyond the engine speed limit applied at operation240, but increase the air flowing through the engine26as will be discussed further below. It should be noted that the operations240and250could be combined into one operation in at least some embodiments. It is contemplated that a different control strategy could be used as soon as the launch mode is activated in operation240regardless of the actual engine speed.

By opening the throttle valve39, air flow through the engine26, as well as the turbocharger170, increases. Increasing air flow through the turbocharger170, while the snowmobile10remains at rest, allows the turbocharger170to spool-up and be fully prepared to supply turbocharger boost during initial acceleration from rest. In order to avoid engagement of the CVT128and the snowmobile10overcoming the braking system89(and accelerating prematurely) due to increasing torque and speed following opening the throttle valve39, the controller150applies a torque limiting process.

Controlling the engine26to limit torque and engine speed, while opening the throttle valve39, is managed by the controller150as follows. As the engine speed increases beyond or approaches approximately 3200 RPM and approaches an engagement speed for the CVT128, the controller150causes a change in the ignition timing for the cylinders such that the engine26is firing inefficiently by delaying combustion in the cylinders. Specifically, as is illustrated in the graph290ofFIG.6, the ignition angle is set to approximately −20 degrees from the top dead center (TDC) position for each piston, such that the spark plugs43are set to ignite the fuel-air mixture when the corresponding piston is at −20 degrees from the TDC position (20 degrees past the TDC position). As the standard ignition timing is to fire approximately 25 degrees from the TDC position, the force produced by each combustion cycle is reduced. It is noted that the same air flow through the engine26is maintained as when the engine26is running in a standard manner, such that the exhaust gas flowing toward the turbocharger170continues generally unchanged in volume.

In some cases, the torque limiting process described above may not be sufficient to limit engine speed or torque, for instance when the throttle valve39is fully open (the accelerator position is 100%). In such a case, the controller150further acts to limit engine speed and torque by deactivating one or more of the cylinders of the engine26. When deactivating a cylinder, the piston continues to cycle, but the fuel injectors41,45do not inject fuel and the spark plugs43do not fire. When deactivating more than one cylinder, different cylinders are deactivated during different cycles, but different approaches are contemplated. For instance, the pattern of activation/deactivation of cylinders could be chosen to manage vibration and heating effects in the engine26. As was the case when delaying ignition, air flow continues through the engine26, aiding to spool up the turbocharger170.

Having increased the throttle valve opening in operation250and with the turbocharger170being at least partially spooled-up, the operator then releases the brake lever88to allow the snowmobile10to accelerate (“launch”). In response to detecting the braking system89being released, the controller150returns the engine to the standard control strategy, removing all engine speed and torque limiting. As is illustrated in the example operation graph290ofFIG.6, launch control is released when the brake is released, where the ignition angle reverts back to the optimal ignition angle (approximately 25 degrees), all cylinders are all fully activated, and the accelerator position is maintained. Having prepared the engine26and the turbocharger170, the engine speed climbs relatively rapidly, from about 3200 RPM to about 8000 RPM over a time frame of about one-half (0.5) second. In comparison, a simulated engine speed curve (in broken line) shows that a similar acceleration (from about 3200 RPM to 8000 RPM) without using the launch control mode of the present description would take about 1.5 seconds. It should be noted that the illustrated simulation is simply one non-limiting example and the exact acceleration time depends on the particular vehicle embodiment.

If at any point, while the launch control mode is activated (from operation230to just prior to the brake lever88being released), the controller150determines that one or more deactivation conditions have been met, the controller150deactivates the launch control mode and returns the snowmobile10to standard operations (see step292of the method300as described below).

The controller150deactivates the launch control mode and returns the snowmobile10to standard operations upon detection of one or more of the following deactivation conditions. Deactivation of the launch control mode could occur upon detection of one or more of: the snowmobile10not being in a forward gear; the engine26not running; the snowmobile10not being in sport mode; the snowmobile10having a speed of greater than 0 km/h (0 mph), i.e. the snowmobile10not being at rest; the temperature of the engine26exceeding mode-acceptable engine temperature limits; and detection of an unacceptable fault. It is contemplated that in different embodiments the controller150may consider only some of these, or additional or alternative conditions.

The deactivation conditions further include time limits on some of the operations described above to aid in preventing the engine26from overheating. As is illustrated inFIG.5, if the braking system89has not been activated within 30 seconds of activating the launch control mode and increasing the engine speed to about 1800 RPM at operation230, the controller150deactivates, at step292, the launch control mode and returns the snowmobile10and the engine26to standard operating conditions. If the accelerator position has not been increased past 0% within 20 seconds after increasing the engine speed to about 3200 RPM at operation240, the controller150returns the engine26to normal idle and removes any torque limiting parameters that may have been activated. Similarly, if the braking system89have not been deactivated within 10 seconds after opening the throttle valve39at operation250, the controller150returns the engine26to normal idle and removes any torque limiting parameters that may have been activated. When the braking system89has been deactivated anew, the snowmobile10then accelerates and is operated according to the standard control strategy, i.e. the standard operating conditions.

In reference toFIG.7, a non-limiting embodiment of controlling the engine26and the snowmobile10, according to the operations described above, is set out in the form of a method300performed by the controller150. In some embodiments, it is contemplated that an additional or substitute computer-implemented system could be used to perform the method300.

The method300begins at step310, with controlling, by the controller150, the engine26according to the standard control strategy. As is mentioned above, the standard control strategy manages the engine26according to standard operational parameters, such as when the snowmobile10is being operated according to typical procedures (e.g. being driven) and the engine26is not being controlled according to the method300.

The method300then continues, at step320, with receiving, by the controller150, a mode indication indicating that the operator of the snowmobile10has selected the launch control mode for accelerating the snowmobile10from rest. As is described above, the mode indication is received at the controller150from the mode input button184, where the operator selects the launch control mode is made available by the controller150. In response to receiving the mode indication, the controller150activates the launch control mode and continues with the method300.

In at least some non-limiting embodiments, the controller150could determine, prior to receiving the mode indication, that one or more initial mode conditions have been met. As is described above, the initial mode conditions, also referred to as activation conditions, could include a variety of parameters, including but not limited to: the snowmobile10being at rest, the temperature of the engine26being within minimum and maximum limits, etc. A more complete non-limiting list of possible initial mode conditions is set out above. In such an embodiment, in response to the initial mode conditions being met, the controller150could enable the mode input184.

In some embodiments, in response to receiving the mode indication and prior to controlling the engine26according to subsequent steps of the method300, the controller150causes the engine26to increase engine speed. As is mentioned above, this increased idle serves as an auditory signal to the operator that the launch control mode has been activated. It is contemplated that the idle may not be increased in at least some embodiments.

The method300then continues, at step330, with receiving, by the controller150, a brake-on indication indicating that the braking system89has been activated.

The method300then continues, at step340, in response to receiving the mode indication and the brake-on indication, with controlling the engine26according to a launch control strategy. As is described above, the controller150causes the engine26to increase engine speed when both the launch control mode is selected and the braking system89is activated. Controlling the engine26according to the launch control strategy includes increasing the speed of the engine26, and limiting the torque output of the engine26if required. If the increased speed of the engine26does not approach the CVT engagement speed, at some instances while controlling the engine26according to the launch control mode it may not be necessary to limit torque output. As is described above, controlling operational conditions of the engine26to limit engine torque output includes delaying combustion ignition by adjusting the ignition timing and/or deactivating one or more cylinders. It is contemplated that alternative or additional approaches could be used to limit torque output of the engine26.

The method300then continues, at step350, while controlling the engine26according to the launch control strategy, with determining an accelerator position of the accelerator86. When the accelerator position is at 0%, the operator has not moved the lever86; when the accelerator positions is greater than 0%, the operator has moved the lever86to request engine power.

The method300then continues, at step360, in response to the accelerator position being greater than zero percent, with controlling the engine26to increase, according to the accelerator position, an opening of the throttle valve39and control operational conditions of the engine39to limit engine torque output. As is described above, air flow increases through the engine26in response to increasing the opening of the throttle valve39according to the accelerator position.

In some embodiments, subsequent to receiving the mode indication and prior to receiving a brake-off indication, the controller150could determine that at least one deactivation condition has been met. In response to one or more deactivation conditions being met, the method300could then include returning to the standard operation mode whereby the snowmobile10is operated according to the standard control strategy.

In some embodiments, while controlling the engine26according to the launch control strategy, the controller150could determine that one or more of the deactivation conditions have been met. The method300could then further include returning to a standard operation mode whereby the snowmobile10is operated according to the standard control strategy.

The method300then continues, at step370, while controlling the engine26according to the second control strategy, receiving a brake-off indication indicating that the braking system89has been released.

The method300then terminates, at step380, in response to receiving the brake off indication, with once again controlling the engine26according to the standard control strategy. As the braking system has been released at this point, the snowmobile10accelerates from rest per standard operational parameters. Specifically, any torque output or engine speed limiting process applied to the engine26(such as combustion delay and/or cylinder deactivation) is removed to allow the engine26to speed up and produce torque according to the position of the accelerator lever86.

As is described above, the rate of acceleration from rest is greater after sequentially controlling the engine26according to the launch control strategy (prior to controlling standard control strategy) than a rate of acceleration from rest of the snowmobile10for corresponding changes in accelerator position when controlling the engine26according to the standard control strategy without previously controlling the engine26according to the launch control strategy. This is due, at least in part, to the spooling-up of the turbocharger170provided during control of the engine26according to the launch control strategy. In response to controlling the engine26according to the launch control strategy then the standard control strategy in the method300, a speed of rotation of the turbocharger170increases. Specifically, the speed of rotation of the turbocharger170upon acceleration from rest is greater, when controlling the engine26according to the launch then standard control strategies, than the speed of rotation of the turbocharger170upon acceleration from rest when controlling the engine26according to the standard control strategy without previously controlling the engine26according to the launch control strategy.

At any point during operation of the method300, subsequent to receiving the mode indication, the controller150could determine that one or more deactivation conditions have been met. As is described above, the launch control mode may need to be deactivated following detection of at least one deactivation condition for a variety of reasons. One non-limiting example of a deactivation condition is a time limit on operating the engine26at an increased engine speed, which is implemented at least in part to aid in avoiding overheating of the engine26. In some cases, the controller150could return the snowmobile10and the engine26to a standard operation mode, at step292, whereby the snowmobile10is operated according to the standard control strategy in response to at least one deactivation condition being met. If, during operation of the method300, a time limit is exceeded after limiting the engine speed to about 3200 RPM at step360, the controller150could also return, at step294, the engine26to normal idle and removes any torque limiting parameters that may have been activated. In such a case, the method300would then progress to step292to return the snowmobile10to standard operation.

It is contemplated that the method300could include additional or different steps, either to perform additional functions and/or to perform the steps described above.

The flowchart200and the method300could, in some non-limiting embodiments, be implemented by an all-terrain vehicle (ATV)400, mutatis mutandis. The ATV400will be described briefly with reference toFIGS.8and9.

The ATV400has a frame422having a front end424and a rear end426defined consistently with a forward travel direction of the ATV400. The ATV400has two front wheels430and two rear wheels430. Each of the four wheels430is provided with low-pressure balloon tires adapted for off-road conditions and traversing rugged terrain. It is contemplated that the ATV400could have six wheels430or only three wheels430.

The two front wheels430are suspended from the frame422by left and right front suspension assemblies432while the two rear wheels430are suspended from the frame422by left and right rear suspension assemblies434. The ATV400further includes a straddle seat440connected to the frame422for accommodating a driver of the ATV400.

An internal combustion engine460(schematically illustrated inFIG.8) is connected to the frame422for powering the ATV400. The engine460is disposed under the straddle seat440. The wheels430are operatively connected to the engine460. Driver footrests442are provided on either side of the straddle seat440and are disposed vertically lower than the straddle seat440to support the driver's feet. The footrests442are connected to the frame422. A steering assembly444is rotationally connected the frame422to enable a driver to steer the ATV400. The steering assembly444includes a handlebar446connected to a steering column assembly (not shown) for actuating steering linkages (not shown) operatively connected to left and right front wheels430.

An accelerator lever450, also referred to as an accelerator450or a throttle operator450, in the form of a thumb-actuated throttle lever, is mounted to the handlebar446. Other types of throttle operators, such as a finger-actuated throttle lever and a twist grip, are also contemplated. A brake actuator488, in the form of a hand brake lever488, is provided on the left side of the handlebar446for controlling a braking system489of the ATV400(shown schematically inFIG.8).

A gear shifter452located near the handlebar446operates a transmission assembly (not shown) and enables the driver to select one of a plurality of gear configurations for operation of the ATV400. In the illustrated embodiment of the ATV400, the gear configurations include park, neutral, reverse, low, and drive. It is contemplated that the sequence and/or number of gear configurations could be different than as shown herein. A driving mode selector button453also enables the driver to select 2×4, 4×4, or sport mode operation of the ATV400, as well the launch control mode as described above with respect to the snowmobile10. A display cluster454, including a number of gauges and buttons, is disposed forwardly of the steering assembly444.

The ATV400further includes a controller (not shown) configured to perform a number of operations including methods described above for accelerating the ATV400from rest using the launch control mode.

The controller of the ATV400is operatively and communicatively connected to various sensors and systems in order to perform the method300(mutatis mutandis) including, but not limited to, at least one of: an ECU connected to the engine460, the brake lever488, the accelerator lever446, an intake air temperature sensor (not shown), the driving mode selector button453, an engine speed sensor (not shown), and an engine temperature sensor (not shown). For the ATV400, the controller is further communicatively connected to the gear shifter452(connected to a gear shifter sensor, for example) in order to determine that the ATV400is in a drive gear before enabling the launch control mode selection capability.

The ATV400further includes other components such as a radiator, headlights, and the like. As it is believed that these components would be readily recognized by one of ordinary skill in the art, further explanation and description of these components will not be provided herein.

The snowmobile10, the ATV400, and the method300implemented in accordance with some non-limiting embodiments of the present technology can be represented as follows, presented in numbered clauses.

CLAUSE 1. A method (300) for accelerating a vehicle (10,400) from rest, the method (300) comprising: controlling, by a controller (150), an engine (26) of the vehicle (10,400) according to a first control strategy; receiving, by the controller (150), a mode indication indicating that an operator of the vehicle (10,400) has selected a launch control mode for accelerating the vehicle (10,400); receiving, by the controller (150), a brake-on indication indicating that a braking system of the vehicle (10,400) has been activated; in response to receiving the mode indication and the brake-on indication, controlling the engine (26), by the controller (150), according to a second control strategy; while controlling the engine (26) according to the second control strategy, determining, by the controller (150), an accelerator position of an accelerator of the vehicle (10,400); in response to the accelerator position being greater than zero, controlling, by the controller (150), the engine (26) to: increase, according to the accelerator position, an opening of a throttle valve of the engine (26), and control operational conditions of the engine (26) to limit engine torque output; while controlling the engine (26) according to the second control strategy, receiving, by the controller (150), a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine (26), by the controller (150), according to the first control strategy, controlling the engine (26) according to the first control strategy with the braking system having been released causing the vehicle (10,400) to accelerate from rest, a first rate of acceleration from rest of the vehicle (10,400) being greater than a second rate of acceleration from rest of the vehicle (10,400) for corresponding changes in accelerator position, the first rate of acceleration corresponding to the vehicle (10,400) accelerating from rest after sequentially controlling the engine (26) according to the first and second control strategies; the second rate of acceleration corresponding to the vehicle (10,400) accelerating from rest by controlling the engine (26) according to the first control strategy without previously controlling the engine (26) according to the second control strategy.

CLAUSE 2. The method (300) of clause 1, wherein, controlling the engine (26) according to the second control strategy includes: increasing a speed of the engine (26), and limiting a torque output of the engine (26).

CLAUSE 3. The method (300) of clause 1 or 2, wherein controlling the engine (26) according to the first control strategy comprises controlling a turbocharged engine (26) of the vehicle (10,400) according to standard operational parameters.

CLAUSE 4. The method (300) of any one of clauses 1 to 3, further comprising: prior to receiving the mode indication, determining, by the controller (150), that each of a plurality of initial mode conditions have been met; and in response to the plurality of initial mode conditions being met, enabling a mode input by the controller (150), the mode indication being sent to the controller (150) from the mode input upon selection of the launch mode by the operator via the mode input.

CLAUSE 5. The method (300) of any one of clauses 1 to 4, further comprising, while controlling the engine (26) according to the second control strategy: determining, by the controller (150), that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle (10,400) is operated according to the first control strategy.

CLAUSE 6. The method (300) of clause 5, wherein determining that the at least one deactivation condition has been met includes determining that a time limit of controlling the engine (26) according to the second control strategy has been reached.

CLAUSE 7. The method (300) of any one of clauses 1 to 6, further comprising, subsequent to receiving the mode indication and prior to receiving the brake-off indication: determining, by the controller (150), that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle (10,400) is operated according to the first control strategy.

CLAUSE 8. The method (300) of any one of clauses 1 to 7, wherein controlling operational conditions of the engine (26) to limit engine torque output comprises at least one of delaying combustion ignition; and deactivating at least one cylinder.

CLAUSE 9. The method (300) of any one of clauses 1 to 8, wherein in response to increasing the opening of the throttle valve according to the accelerator position, air flow increases through the engine (26).

CLAUSE 10. The method (300) of any one of clauses 1 to 9, wherein, in response to controlling the engine (26) according to the first and second control strategies, a speed of rotation of a turbocharger of the vehicle (10,400) increases.

CLAUSE 11. The method (300) of any one of clauses 1 to 10, wherein, a first speed of rotation of a turbocharger of the vehicle (10,400) upon acceleration from rest is greater than a second speed of rotation of the turbocharger upon acceleration from rest; the first speed of rotation corresponds to the vehicle (10,400) accelerating from rest after sequentially controlling the engine (26) according to the first and second control strategies; and the second speed of rotation corresponds to the vehicle (10,400) accelerating from rest by controlling the engine (26) according to the first control strategy without previously controlling the engine (26) according to the second control strategy.

CLAUSE 12. The method (300) of any one of clauses 1 to 11, wherein, in response to receiving the mode indication and prior to controlling the engine (26) according to the second strategy, controlling the engine (26) to increase engine speed.

CLAUSE 13. The method (300) of clause 12, further comprising, subsequent to receiving the mode indication and prior to controlling the engine (26) according to the first strategy subsequent to receiving the mode indication: determining, by the controller (150), that at least one deactivation condition has been met; and in response to the at least one deactivation condition being met, returning to a standard operation mode whereby the vehicle (10,400) is operated according to the first control strategy.

CLAUSE 14. The method (300) of clause 13, wherein determining that the at least one deactivation condition has been met includes determining that a time limit of increased engine speed has been reached.

CLAUSE 15. The method of clause 1, further comprising: determining, by the controller, that a speed of the engine has surpassed a threshold engine speed; and wherein the controller controls the engine according to the second control strategy in response to receiving the mode indication and the brake-on indication, and determining that the engine speed has surpassed a threshold engine speed.

CLAUSE 16. A vehicle (10,400) comprising: a frame; at least one seat connected to the frame; an engine (26) supported by the frame; a turbocharger operatively connected to the engine (26); a controller (150) communicatively connected to the engine (26); and an accelerator communicatively connected to the controller (150), the controller (150) being configured to perform the method (300) of any one of the clauses1to15.

CLAUSE 17. A vehicle (10,400) comprising: a frame; at least two ground engaging members connected to the frame; a braking system operatively connected to at least one of the at least two ground engaging members; at least one seat connected to the frame; an engine (26) supported by the frame; a turbocharger operatively connected to the engine (26); a controller (150) communicatively connected to the engine (26); and an accelerator communicatively connected to the controller (150), the controller (150) being configured to perform the steps of: controlling, by a controller (150), an engine (26) of the vehicle (10,400) according to a first control strategy; receiving, by the controller (150), a mode indication indicating that an operator of the vehicle (10,400) has selected a launch mode for accelerating the vehicle (10,400); receiving, by the controller (150), a brake-on indication indicating that a braking system of the vehicle (10,400) has been activated; in response to receiving the mode indication and the brake-on indication, controlling the engine (26), by the controller (150), according to a second control strategy; while controlling the engine (26) according to the second control strategy, determining, by the controller (150), an accelerator position of an accelerator of the vehicle (10,400); in response to the accelerator position being greater than zero, controlling, by the controller (150), the engine (26) to: increase, according to the accelerator position, an opening of a throttle valve of the engine (26), and control operational conditions of the engine (26) to limit engine torque output; while controlling the engine (26) according to the second control strategy, receiving, by the controller (150), a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine (26), by the controller (150), according to the first control strategy, controlling the engine (26) according to the first control strategy with the braking system having been released causing the vehicle (10,400) to accelerate from rest, a first rate of acceleration from rest of the vehicle (10,400) being greater than a second rate of acceleration from rest of the vehicle (10,400) for corresponding changes in accelerator position, the first rate of acceleration corresponding to the vehicle (10,400) accelerating from rest after sequentially controlling the engine (26) according to the first and second control strategies; the second rate of acceleration corresponding to the vehicle (10,400) accelerating from rest by controlling the engine (26) according to the first control strategy without previously controlling the engine (26) according to the second control strategy.

CLAUSE 18. The vehicle (10,400) of clause 17, further comprising: a mode input communicatively connected to the controller (150); and wherein the controller (150) is further configured to perform the steps of: prior to receiving the mode indication, determining, by the controller (150), that each of a plurality of initial mode conditions have been met, and in response to the plurality of initial mode conditions being met, enabling the mode input by the controller (150) to allow the operator to select the launch mode.

CLAUSE 19. The vehicle (10,400) of clause 17 or 18, wherein: the vehicle (10) is a snowmobile (10); the at least two ground engaging elements include: two skis connected to the frame, and an endless track disposed rearward of the two skis; the at least one seat is at least one straddle-seat; and the accelerator is an accelerator lever.

CLAUSE 20. The vehicle (10,400) of any one of clauses 17 to 19, wherein: the vehicle (400) is an all-terrain vehicle (400) (ATV); the at least two ground engaging elements include at least two wheels; the at least one seat is at least one straddle-seat; and the accelerator is an accelerator lever.

CLAUSE 21. A method (300) for accelerating a vehicle (10,400) from rest, the method (300) comprising: controlling, by a controller (150), an engine (26) of the vehicle (10,400), the engine (26) having a first mode and a second mode: the first mode controlling the engine speed from a first idle speed to a first maximum engine speed with respect to a corresponding idle accelerator position and a maximum accelerator position; the second mode controlling the engine speed from a second idle speed to a second maximum engine speed with respect to the corresponding idle acceleration position and the maximum acceleration position, the second maximum engine speed being less than the first maximum engine speed, receiving, by the controller (150), a mode indication indicating that an operator of the vehicle (10,400) has selected a launch mode for accelerating the vehicle (10,400); receiving, by the controller (150), a brake-on indication indicating that a braking system of the vehicle (10,400) has been activated; in response to receiving the mode indication and the brake-on indication, controlling the engine (26), by the controller (150), according to the second mode; while controlling the engine (26) according to the second mode, receiving, by the controller (150), a brake-off indication indicating that the braking system has been released; and in response to receiving the brake-off indication, controlling the engine (26), by the controller (150), according to the first mode, controlling the engine (26) according to the first mode with the braking system having been released causing the vehicle (10,400) to accelerate from rest.