Patent Application
20250092837
As compared to snowmobiles with 4-stroke internal-combustion engines, snowmobiles with 2-stroke internal-combustion engines are much lighter and maneuverable, and provide greater power-to-weight ratios. Further, snowmobiles with 2-stroke engines may start easier in cold weather. For these and other reasons, many consumers choose 2-stroke snowmobiles over 4-stroke snowmobiles. However, unlike modern 4-stroke snowmobiles which employ electronic throttle control (ETC), known 2-stroke snowmobiles still utilize mechanical throttle controls, such as a throttle cable connecting the operator throttle lever to the throttle valve in the engine throttle body. Consequently, 2-stroke snowmobiles cannot provide the many advantages offered by ETC.
Embodiments of the present disclosure include an electronic throttle-control system for a snowmobile. In one such embodiment, the electronic throttle control system includes: an electronic control unit (ECU) including a processor and a memory device storing at least one throttle-control translation map; a throttle-input sensor in electrical communication with the ECU and configured to sense an input from an operator-actuated throttle device; and a 2-stroke internal-combustion engine. The 2-stroke internal-combustion engine may include: an electronic throttle-valve actuator in electrical connection with the ECU and having an actuator motor and gear train; a throttle body for controlling airflow to one or more combustion chambers of the 2-stroke internal-combustion engine, the throttle body defining a first throttle bore and a second throttle bore; a first throttle valve in the first throttle bore and a second throttle valve in the second throttle bore; and a throttle valve control shaft coupled to the first throttle valve and the second throttle valve, and to the gear train, such that movement of the actuator motor and gear train causes the throttle valve control shaft to rotate and move the first and second throttle valves; a throttle-position sensor in electrical communication with the ECU and configured to sense an actual position of the first and second throttle valves. Further, the ECU may be configured to receive a signal representing a throttle-position input from the throttle-input sensor and to determine a throttle-demand position corresponding to a position of the first throttle valve in the first throttle bore and a position of the second throttle valve in the second throttle bore, based on the throttle-position input and throttle-control translation map.
Another embodiment of the disclosure is a method of controlling a starting mode of snowmobile having an electronic-control unit (ECU) with a processor, and a 2-stroke combustion engine with an electronic throttle body having a first throttle valve, a second throttle valve, a throttle-position sensor, and an actuator for actuating the first and second throttle valves. The method includes the steps of: determining whether an electronic throttle body drive-voltage generated by the 2-stroke combustion engine is above a threshold voltage; determining whether an engine speed of the 2-stroke combustion engine is above a first engine-speed threshold; when the generated voltage is at or above the critical threshold voltage and the speed of the 2-stroke combustion engine is above a threshold engine-speed threshold, setting a throttle position of the first throttle valve and the second throttle valve to a neutral-throttle position; after a predetermined period of time, determine whether the engine speed is greater than a second engine-speed threshold; and when the engine speed is greater than the second engine-speed threshold, changing a position of the first throttle valve and the second throttle valve from the neutral-throttle position to an initial throttle-operating position, by controlling the actuator with the processor of the ECU.
Yet another embodiment of the disclosure includes a method of controlling a snowmobile having an electronic-control unit (ECU) with a processor, a memory storing one or more throttle-control translation maps, and a 2-stroke combustion engine with an electronic throttle body having a first throttle valve, a second throttle valve, a throttle-position sensor, an actuator for actuating the first and second throttle valves, and an engine-speed sensor. In this embodiment, the method includes: storing a predetermined idle-speed throttle-valve position and the one or more throttle-control translation maps in the memory; determining with the ECU a throttle-demand valve position, the throttle-demand valve position corresponding to a throttle-demand valve effective area of the first and second throttle valves; comparing the throttle-demand valve position to the predetermined idle-speed throttle-valve position; receiving at the ECU, an output of the engine-speed sensor indicating an actual engine speed of the 2-stroke internal-combustion engine; comparing the actual engine speed with a predetermined engine-idle speed; selecting a throttle-control translation map stored in the memory when the throttle-demand position effective flow area is greater than the predetermined idle-speed throttle position effective flow area and when the actual engine speed is greater than the predetermined idle engine speed; controlling the actuator using the ECU to set a first position of the first throttle valve in the first throttle bore and a first position of the second throttle valve in the second throttle bore based on the selected throttle-control translation map; determining whether an engine fault is present and controlling the actuator using the ECU to set a second position of the first throttle valve in the first throttle bore and a second position of the second throttle valve in the second throttle bore when a fault is present; and determining whether a ground speed or engine speed exceeds a maximum speed limit and controlling the actuator using the ECU to set a third position of the first throttle valve in the first throttle bore and a third position of the second throttle valve in the second throttle bore to reduce ground speed or engine speed to be less than the maximum speed limit.
The above summary of the various representative embodiments of the invention is not intended to describe each illustrated embodiment or every implementation of the invention. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the invention. The figures in the detailed description that follow more particularly exemplify these embodiments.
The disclosure can be understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
For the purposes of understanding the disclosure, reference will now be made to the embodiments illustrated in the drawings, which are described below. While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all combinations, modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Electronic throttle control (ETC), while prevalent on 4-stroke powersports products, has never successfully been implemented on a 2-stroke snowmobile. Over time, more safety features are being implemented on 2-stroke snowmobiles, and their versatility is growing. However, conventional methods for manipulating the feel and/or use of the snowmobile, as well as means of power limiting the snowmobile, have not risen to the level to provide for a true multipurpose 2-stroke snowmobile. Dual-bore, on-throttle, electrically-driven ETC systems herein directed to a 2-stroke snowmobile allow for reduced mass, more precise control and faster response, in addition to reduced throttle-pull effort, thereby providing significantly improved vehicle-feel manipulation, speed limiting, power limiting, start and idle improvements as compared to cable-driven mechanically-actuated throttle-body systems of known 2-stoke snowmobiles.
Further, the ability to create a plurality of drive modes on a 2-stroke engine facilitates implementation of more effective vehicle and engine speed-limiting options to control the power output of the engine to meet the needs of riders of a wider range of skill levels. For example, a reduced maximum-throttle opening with a slower ramp between input and output command can serve as an operational mode for entry-level or inexperienced riders while a 1:1 translation between input and output can serve as a operational mode for experienced riders. Furthermore a throttle map in which the throttle opens further than the user command at certain operating conditions can be used for racing or mountain applications to enhance throttle response. Additionally, the use of ETC can serve as a user-adjustable speed-limiting function that can be used with or without a parental-lock passcode through the gauge to limit vehicle speed so that the operator can use the vehicle according to one of the aforementioned throttle-control modes up to a programable vehicle speed, at which point the throttles will begin to close to maintain the speed.
Furthermore, the use of ETC can be used as a vehicle power-limiting function for circumstances such as: engine overheat, exhaust temperature overheat, transmission low range operation, detonation protection, low-fuel operation and vehicle speed limiting for track durability. Embodiments of snowmobiles with 2-stroke ETC as described herein increase the operational capacity of a single vehicle that is usable for a wide range of operators from the inexperienced to the expert.
Embodiments of the disclosure, and as described in further detail below, include a snowmobile with a 2-stroke internal-combustion engine having a dual bore electronic throttle body with a single shaft connecting the two plates/valves to an electric motor output drive that is used to control the airflow going into the engine. A handlebar mounted throttle-input sensor is used to determine throttle input by the user. An ECU is then able to translate this user input to a throttle body command through a plurality of throttle-control translation maps that are used to alter the performance characteristics of the engine. The plurality of translation maps are used to alter the feel of the vehicle by limiting engine airflow and/or rate at which throttle is applied relative to the users input. A map which features a smoother translation between the user input and the throttle output can be utilized to enhance low speed drivability when towing or navigating tight operating conditions. Additionally, ETC can be used for vehicle speed limiting on mountain snowmobiles equipped with deeper lug tracks as a means of preventing or mitigating the delamination of the track lugs causing track failure.
ETC can also serve as an effective means of power limiting and can be used independently or in conjunction with utilization of the exhaust valves as a means of controlling the airflow through the engine and therefore, the power output of the engine. In the case of elevated engine water or exhaust gas temperature, the exhaust valves may be forced down to limit airflow of the engine or could be used in conjunction with the ETC to force operation of the engine into a region more likely to mitigate this circumstance; usually by limiting power of the engine to reduce heat production both through heat rejection to the cooling system and heat generation through combustion. In the case of engine detonation, instead of forcing the exhaust valves down, a progressive drop in maximum operating throttle position can be implemented to mitigate detonation while still allowing the maximum power allowable for the given circumstances which allows for a less intrusive means of power limiting and engine protection. In the case of a sensor or vehicle fault, a maximum allowable throttle position that overrides the translation maps to allow the rider to limp home for the purpose of repairs or diagnostics to minimize the potential for engine failure may be implemented. For example, sensors may sense and indicate low-fuel pressure, or other engine faults. Vehicle faults may include non-engine related faults, including faults caused by operation of snowmobile 10, such as certain brake-throttle interactions, such as operating the throttle while applying the brakes for period of time.
Furthermore, the use of ETC allows for variable throttle angle to be used for starting of the engine to control the flare of the engine in starting conditions according to elevation of operation. Additionally, the ETC can be used as closed loop idle control mechanism to control the engine speed according to a calibratable setpoint.
Referring to
Snowmobile 10 further includes body assembly 28 comprised of multiple body panels covering certain components and systems of snowmobile 10, including portions of frame assembly 12, front suspension assembly 22, and powertrain assembly 30.
Referring specifically to
Powertrain assembly 30 provides power to endless track 20 to move snowmobile 10. Powertrain assembly 30 is supported by front frame portion 14 and includes 2-stroke, internal-combustion engine 50 and a transmission (not shown).
As will be understood by those of ordinary skill in the art, two-stroke or 2-stroke (sometimes referred to as “2-cycle”), internal-combustion engine 50 includes various systems and components, such as an engine block with a combustion chamber, pistons, intake and exhaust valves, a fuel system, which may be an electronic fuel-injection (EFI) system, an electrical system, a cooling system, an exhaust system, and various sensors, such as a throttle position sensor, engine-speed sensor, crank position sensor, and so on. Various embodiments of snowmobiles, snowmobile engines, systems and so on are known in the art and are described in U.S. Pat. No. 8,590,654, issued Nov. 26, 2013 and entitled “Snowmobile,” in U.S. Pat. No. 8,733,773, issued May 27, 2014 and entitled “Snowmobile Having Improved Clearance for Deep Snow,” in U.S. Patent Pub No. 2014/0332293A1, published Jul. 23, 2014 and entitled “Snowmobile,” and in U.S. Pat. No. 11,110,994, issued Sep. 7, 2021 and entitled “Snowmobile,” all of which are assigned to Polaris Industries Inc., and all of which are incorporated herein by reference in their entireties.
Powertrain assembly 30 also includes a drivetrain assembly 52 comprising a countershaft or jackshaft 54 and a track driveshaft 56. Jackshaft 54 is operably coupled with the transmission and, in embodiments using a continuously variable transmission (“CVT”), is operably coupled with the secondary or driven pulley. Jackshaft 54 also is operably coupled to driveshaft 56 through a belt/chain drive assembly 58. Belt/chain drive assembly 58 includes a drive sprocket 60, a driven sprocket 62, and a belt or chain 64 rotatably entrained with drive and driven sprockets 60, 62. Driven sprocket 62 is coupled with driveshaft 56. In operation, the crankshaft (not shown) of engine 50 drives the transmission, thereby causing the transmission to output power (e.g., rotation) to jackshaft 54. Jackshaft 54 then drives driveshaft 56 through belt/chain drive assembly 58. As a result, driveshaft 56 rotates within a portion of tunnel 34.
Driveshaft 56 engages an inner surface of track 20, such that as jackshaft 54 drives driveshaft 56, through belt/chain drive assembly 58, driveshaft 56 causes track 20 to rotate and move snowmobile 10.
An engine 50 speed is controlled, at least in part, by the operator controlling throttle-input device 80, which may be a throttle lever or similar. A position of the throttle-input device 81 may be detected by a throttle-input sensor 140 (discussed further with respect to
Snowmobile 10 also includes brake system 70, which may be a dry or wet brake system controlled by brake lever 82. In an embodiment, brake system 70 is a hydraulic disc-brake system, and is coupled to the transmission. Brake system 70 may be directly coupled to jackshaft 54, or to other portions of the transmission.
Referring to
In the embodiment depicted, 2-stroke, internal-combustion engine 50 is a two-cylinder engine, with two combustion chambers and two pistons, though it will be understood that 2-stroke, internal-combustion engine 50 may comprise a single-cylinder engine, or may comprise more than two combustion chambers, based on various engine factors, including engine size and desired engine power output.
Referring also to
In the embodiment depicted, throttle body 90 defines two throttle bores 92 and two throttle valves 94, one for each combustion chamber, though in other embodiments, throttle body 90 may define a single throttle bore 92 with a single throttle valve 94, or more than two throttle bores with valves, depending on various engine design factors, including the number of combustion chambers defined by engine 50. In an embodiment, throttle body 90 defines one bore 92 with one throttle valve 94, for each combustion chamber of engine 50.
As will be understood by those of ordinary skill in the art, each throttle bore 92 forms a passageway or channel for combustion air to flow into engine 50 combustion chambers. In embodiments, each throttle bore 92 defines a generally cylindrical through passageway, with a circular opening. Each throttle bore 92, including bores 92a and 92b, may be of substantially equal size, with a same or similar-sized opening. In an embodiment, a diameter D of each throttle bore 92 may be in a range of about 30 mm to about 50 mm.
Throttle valves 94, including valves 94a and 94b, in an embodiment, comprise butterfly valves that may form a substantially flat, circular disc or plate. Each butterfly valve 94 fits at least partially within an interior portion of its respective bore 92, depending on the rotated position of the valve. Each butterfly valve 94 may also define a minimum-air flow, or idle-air flow, hole 104, including holes 104a and 104b, to allow for some airflow through valve 94, even when the valve is in a closed position. Each throttle valve 94 is centered within its respective throttle bore 92, such that when each throttle valve 94 is in a closed position, as depicted in
First and second throttle valves 94a and 94b are distributed along a lateral axis A, separated by a center-to-center pitch distance P. In an embodiment, pitch P is in a range of about 100 mm to 200 mm; in another embodiment, pitch P is in a range of about 130 mm to 140 mm; in another embodiment, pitch P is approximately 130 mm. Pitch P may be increased to accommodate larger 2-stroke engines which may have larger cylinders and combustion chambers that have centers spaced further apart laterally.
Actuator shaft 102 extends from actuator gear train 100 along lateral axis A, and is mechanically coupled to each of throttle valves 94a and 94b via a pair of fasteners 95, as depicted. Actuator shaft 102 may comprise a single shaft, or multiple mechanically-joined shafts. Portions of actuator shaft 102 may be flat, as depicted, to conform to flat outer surfaces of throttle valves 94.
Throttle-valve actuator 96, including actuator motor 98, is in electrical communication with, and controlled by, the snowmobile ECU, as will be described further below with respect to
Referring also to
Referring specifically to
In an embodiment, throttle valve 94 is rotatable between the fully-closed throttle position (minimum throttle-demand effective flow area) and the fully-open throttle position (maximum throttle-demand effective flow area), and a plurality of positions between the closed throttle position and the open throttle position, by throttle-valve actuator 96, as controlled by ECU 128 (
Referring to
Operator inputs 120 include various devices and means for an operator of snowmobile 10 to control and interface with snowmobile 10 and ECU 128. Operator inputs 120 may include a device for selecting an operating mode of snowmobile 10 and its 2-stroke engine 50, i.e., mode control 122, such as an electrical or mechanical switch, or a graphical button on a display device, such as display 126. Operator inputs 120 may also include select input device 124 for selecting displayed operational settings or options. Other operator inputs 120 associated with a gauge of snowmobile may be included. In one such embodiments, and as discussed further below, an operator may interface with the gauge to enter a maximum speed limit, or other information intended to limit a ground speed, engine speed, or other vehicle operation limit.
Operator inputs 120 may collectively comprise a human-machine interface and may include display device 126. Display 126 may be configured to display various information to an operator of snowmobile 10, such as ground speed, engine speed, which may be measured in revolution per minute (RPM), engine temperature, outside temperature, and so on. In an embodiment, display 126 may comprise a touchscreen display configured to receive input from the operator, as well as being configured to display information to the operator.
Electronic control unit (ECU) 128 functions as a vehicle controller and though depicted as a single ECU, may in some embodiments comprise one or more ECUs having processors and memory for controlling electrical systems or subsystems of snowmobile 10. Additional controllers or ECUs not depicted may also be present, such as those specific to control operating systems, including engine 50 and security-related devices, and/or other connected devices. Functions of ECU 128 may be performed by hardware and/or computer instructions saved on memory devices, such as non-transient, computer-readable storage mediums.
Memory devices, in an embodiment, includes computer-readable media in the form of volatile and/or nonvolatile memory and may be removable and/or non-removable. Embodiments include random access memory (RAM), read only memory (ROM), electronically erasable programmable read only memory (EE-PROM), flash memory, optical or magnetic storage devices, and/or other medium that can be used to store information and can be accessed by electronic devices. Memory devices are configured to store various types of vehicle data and executable computer-program instructions.
ECU 128 is in electrical communication with operator inputs 120 and display 126, receiving input from the operator of snowmobile 10 and displaying or otherwise communication information to the operator.
ECU 128 may include a controller or control system 130 to directed to controlling 2-stroke engine 50, and a controller or control subsystem 132 directed to controlling security devices and systems. ECU 128 with its engine control 130 is configured to control various operations of 2-stroke engine 50, including electronic throttle-valve actuator 96, as described above, and as described further below with respect to
The various sensors, including sensors 134-144 are in electrical communication with ECU 128. Vehicle-speed sensor 134 detects and indicates a ground speed of snowmobile 10. Gear-position sensor 136 detects and indicates a gear position of snowmobile 10. In an embodiment, gear-position sensor 136 indicates whether snowmobile 10 is in a low gear. Throttle-input sensor 138 detects and indicates a position of user-actuated throttle input device 80. The position of throttle input device 80 generally indicates a throttle input that is requested by the operator. In an embodiment, throttle-input sensor 138 is located at or near throttle-input device 80. Sensor 138 detects the requested throttle position and communicates that to ECU 128. Engine-speed sensor 140 detects and indicates an engine speed, which may be measured in RPMs. Throttle-position sensor 142 detects and indicates an actual position of one or both of throttle valves 94. In an embodiment, throttle-position sensor 142 may be located at or near throttle-valve actuator 96. Other engine sensors 144 may also be present and in communication with ECU 128. Other engine sensors 144 may include one or more fault sensors, engine-temperature sensor, exhaust-temperature sensor, an outside-air temperature sensor, barometric-pressure sensor, fuel-pressure sensor, low-fuel sensor, ECU-voltage sensor, brake sensor, e.g., to detect whether brakes are engaged, and other such sensors.
Snowmobile 10 may also include a CANBUS or other vehicle network connecting the various controllers and electrical devices of snowmobile 10.
As also described above with respect to
Referring to
More specifically, in this embodiment, ECU 128 receives vehicle speed input 160, operator throttle input, 162 and engine speed 164 from vehicle-speed sensor 134, throttle-input sensor 138 and engine-speed sensor 140, respectively. “Input” may comprise electrical signals or data transmitted from the respective sensors or associated sensors and controllers. The operator of snowmobile 10 interfaces with operator inputs 120 (see also
In an embodiment, mode-change interlocks 168 prevent a throttle mode from being changed during operation, or when certain engine and/or vehicle criteria are not met. Such criteria may include, but not be limited to, being below a predetermined threshold vehicle speed or engine speed, being at or below a predetermined throttle position, and other criteria. Mode-change interlocks 168 may comprise one or more software algorithms stored in memory associated with ECU 128, and executed by a processor of ECU 128.
In an embodiment, ECU 128 may transmit information, a “request message” to gauge 166 and/or display 126 (
In this control embodiment, based on vehicle and engine speed, throttle input and user selection, ECU 128 determines or confirms a throttle mode. As described briefly above, a “throttle mode” corresponds to a selectable, predetermined throttle-control translation map. A throttle-control translation map “translates” or correlates an operator-requested throttle input, such as throttle-input 162, to a throttle output, or throttle position as determined by ECU 128. Generally, for any particular throttle input, the throttle map identifies an associated throttle output corresponding to throttle valve positioning. Such a throttle output might be the same as the requested throttle input in a first throttle mode, might be less than a requested throttle input in a throttle-limiting mode, or may be greater than a requested throttle input in a third throttle mode. Such throttle modes might respectively be labeled or identified by various labels, such as a standard throttle mode, limited throttle mode, and a dynamic or race throttle mode. Throttle-control translation maps are discussed in greater detail below with respect to
After determining or selecting the throttle-control mode at step 170, ECU 128 then issues throttle commands 172 to control throttle-control actuator 96 and a position of throttle valves 94 according to the selected throttle-control mode and associated throttle-control translation map. In this particular embodiment, no throttle position sensing input or output filtering occurs. A lack of filtering on input/output signals allows for faster response without latency. In an alternate embodiment that employs limited or reduced filtering, the number of filtering samples is less than 10 samples. In one embodiment, ECU 128 utilizes a PID loop of less than 1 kHz with a greater than 1 kHz calculation loop. In one such embodiment, ECU 128 utilizes a 500 Hz PID loop with 2 kHz calculation loop to continuously determine throttle commands 172. Such embodiments reduce latency and improve throttle response, such that the throttle response of ETC system 88 resembles that of a mechanically-operated throttle.
Referring to
As depicted, in this embodiment, ECU 128 receives vehicle speed input 160, throttle input 162 and engine speed input 164 from vehicle-speed sensor 134, throttle-input sensor 138 and engine-speed sensor 140, respectively. In this embodiment, ECU 128 also receives gear-position input 174 from gear-position sensor 136, indicating whether snowmobile 10 is in a low-gear position. As such, ECU 128 also takes into account a gear ratio of snowmobile 10, and adjusts throttle output and throttle valve 94 positions accordingly. In other embodiments, ECU 128 may also receive data and input from other vehicle and engine sensors when determining an appropriate throttle output or throttle position.
Similar to the operation described in
More specifically, in this embodiment of a control method and system, such system controls include vehicle speed-limit throttle control 176, geofencing control 178, user-mode lockout 180 and user passcode control 182. Such controls may be used to limit performance and speed of snowmobile 10, including limiting access to high-performance throttle modes, provide passcode protection for inexperienced operators, and limit geographical use via geofencing.
Control of speed-limits may be implement with vehicle speed-limit throttle control 176. In an embodiment, an operator, which may be a parent or adult, for example, may interact with operator inputs 120 to enter a desired speed-limit control, which may be a maximum speed limit. ECU 128 with speed-limit throttle control 176 saves the selected speed limit input in a memory, monitors snowmobile 10 ground speed with vehicle-speed sensor 134, and electronically limits a position of throttle valves 94 to maintain a speed at or below the selected speed.
In an embodiment, to implement a vehicle speed limit as described above, a passcode is required, as indicated by user passcode control 182. In one such embodiment, a passcode must be entered by an operator via operator inputs 120 or gauge control 166, before limitation on vehicle speed may be entered, and/or before a speed limitation may be removed. As such, a parent, owner or other responsible person may use the passcode to ensure snowmobile 10 with a potentially inexperienced operator, or any other operator, does not exceed the selected speed limit.
User mode lockout control 180 allows an operator to define a user profile, which may include the functionality of enabling or disabling one or more available throttle-control modes. For example, a performance-limited youth user mode may be defined, and a performance-enhanced or race-oriented mode may be disabled by an operator interacting with user inputs 120. In an embodiment, ECU 128 causes throttle-control modes to be displayed at gauge 166 or display 126, such that the operator may view and select those throttle-control modes to be enabled or disabled for a particular user or operator profile. In an embodiment, the operator may be required to input a passcode to make changes to change user or throttle modes.
Geofencing control 178 may be included to create a virtual geographic fence or boundary, within which, operation of all or some functions of snowmobile 10 is available to an operator. However, outside the virtual boundary, operation is restricted. In one such embodiment, geofence boundaries may be entered via operator inputs 120, defining an area in which an inexperienced or youthful operator may operate snowmobile 10. Outside the defined boundaries, however, operation of snowmobile 10 may be restricted to low speed limits, to particular modes, or to even cease operation.
Embodiments of speed-limit throttle control 176, geofencing control 178, user-mode lockout 180 and user passcode control 182 may comprise dedicated hardware components and one or more software algorithms stored in memory associated with ECU 128, and executed by a processor of ECU 128, or a processor in communication with ECU 128.
Referring to
Referring specifically to the graph of
Engine speed ES may be measured in RPMs, as detected by engine-speed sensor 140 and communicated to ECU 128.
Voltage V is a voltage generated by an electrical system of snowmobile 10, and specifically from a power-generating device of the electrical system, such as a magneto or alternator. In an embodiment, snowmobile 10 does not include a battery or electric motor starter, but rather, includes a pull cord or rope operable to rotate engine 50 crankshaft and magneto (or other electrical-generating component). Pulling the cord rotates the crankshaft and magneto, generating power, which may be measured in generated voltage V. In some embodiments, 2-stroke snowmobile 10 may include a battery powering a starter motor, which in turn rotates the crankshaft and magneto, thereby generating voltage V.
Throttle position TP corresponds to a position of throttle valves 94, ranging from a closed or minimum-air flow position to a fully-open or maximum air-flow position, and positions therebetween. Throttle position TP may be indicated or measured as a percentage of a fully-open position, such as a 0% open position to a 100% open position.
At time T0, 2-stroke engine 50 is not yet started or operating; throttle position TP is closed, i.e., throttle valves 94 are in a fully-closed or minimal air-flow position, or at a 0% open position; engine speed ES is zero; and voltage V is zero.
Generally, throttle position TP is determined and controlled by electronic throttle-control system 88, including ECU 128. However, until ECU 128 and system 88 is sufficiently powered, throttle position TP is not actively controlled. In this low-flow start embodiment, throttle position TP is initially closed, pending actuation by throttle-valve actuator 96 as controlled by ECU 128.
At time T1, an operator initiates an engine-start sequence, such as by pulling a start cord or depressing a start button causing a battery to power a starter motor of snowmobile 50. Initiating the engine-start sequence causes pistons, crankshaft, magneto or alternator, of 2-stroke, internal-combustion engine 50 to rotate. As such, engine speed ES begins to increase at time T1.
At time T2, rotation of engine 50 generates sufficient power such that voltage V rises above 0 volts to a threshold voltage V1. In an embodiment, voltage V2 at time T3 is sufficient to turn on an H-bridge electronic circuit of the electrical-generation system of snowmobile 10, such that throttle-valve actuator 96 is sufficiently powered to begin opening throttle valves 94.
After time T2, and as time approaches T3, engine 50 rotation continues as a result of initiation of the engine start sequence. Voltage V rises above V1, while engine speed ES also continues to increase.
At time T3, the generated power and corresponding voltage is sufficient to allow normal electrical operations, such that ECU 128 commands throttle position TP to increase rapidly through TP1 up to TP2 at time T4.
At time T4, voltage V is near a maximum voltage V3 as engines speed increases. Throttle position TP is at TP2, which is above a necessary air flow for engine idle. Electronic throttle-control system 88 with ECU 128 initiates an idle control sequence to change throttle position TP to a position appropriate for engine idle. As such, electronic throttle-control system 88 with ECU 128 processes engine sensor inputs, such as those described above, and begins to close throttle valves 94. i.e., changes the throttle position to approach TP1 in the time interval of T4 to T5. Initially increasing throttle position TP to TP2 to allow for relatively high air flow, followed by reducing air flow at TP1, allows the engine speed to rise above idle speed and then settle to the target so that it can more effectively burn the fuel used for the starting event to reduce smoke, improve idle consistency and minimize spark plug fouling.
At time T5, engine speed ES is at a predetermined idle speed, which in an embodiment may be in a range of 1,000 RPM to 1.500 RPM. Voltage V is in a steady state at V3. From time T5 to T6, electronic throttle-control system 88 with ECU 128 holds throttle position TP at idle position TP1.
At time T6, electronic throttle-control system 88 with ECU 128 initializes an “idle” proportional-integral-derivative (PID) control loop, which is then actively executed starting at time T6 and extending thereafter to time T7 and beyond, and until an operator or ECU 128 calls for operation above engine idle.
Consequently.
Referring to
In an embodiment, throttle valves 94 may be held in throttle position TP2 by a biasing spring, then held in that position until time T4 when voltage V has surpassed threshold voltage V1, and initialization of the PID idle loop is initiated. At time T4, electronic throttle-valve control system 88 with ECU 128 commands actuation of throttle valves 94, which counters the spring bias, and actuates throttle valves 94 to an idle throttle position TP1, which is then maintained.
Referring to
The time period of T0 to T1 represents a star-up time period; time period T1 to T2 represents a first engine-idle state or control period; time period T2 to T3 represents a first position-based throttle control period, where an operator selects or inputs a throttle position and a throttle output or actual throttle position is determined by electronic throttle-control system 88 and ECU 128; time period T3 to T4 represents a fixed-state output; time period T4 to T5 represents a second position-based throttle control period; and time period T5 to T6 represents a second engine-idle control period.
The dashed line indicates throttle input, corresponding generally to an amount of throttle requested by an operator of snowmobile 10 operating throttle-input device 80. In an embodiment, throttle input corresponds to a selected position of throttle-input device 80, which also corresponds to a detected mechanical position of throttle-input device 80 as sensed or detected by throttle-input sensor 138. In one such embodiment, throttle input may range from a minimum input of zero, to a maximum requested throttle input of 100%. In an embodiment, and as depicted in
The solid line and the long-dash-short-dash line depicted in
The solid line represents a second set of throttle positions TP corresponding to a race throttle mode and a second throttle-control translation map, while the long-dash-short-dash line represents a third set of throttle positions TP corresponding to a limited throttle mode and a third throttle-control translation map. The second and third sets of throttle positions TP are determined, at least in part, by the throttle input. Generally, for the second set of throttle positions TP corresponding to a race throttle mode, each throttle position TP is equal to, or greater than a corresponding throttle input, and for the third set of throttle positions TP corresponding to the limited throttle mode, each throttle position TP is equal to, or less than, a corresponding throttle input.
In operation, and as will be described further below, ECU 128 receives throttle input in the form of data or a signal from throttle-input sensor 138, based on operator interaction with throttle-input device 80. ECU 128 then translates the received throttle input to a throttle body command through one of a plurality of throttle-control translation maps that are used to alter the performance characteristics of engine 50. In an embodiment, the plurality of translation maps are used to alter the feel of snowmobile 10 by controlling engine air flow through throttle valves 94 and/or controlling a rate at which throttle is applied relative to the operator's input. For example, a reduced maximum throttle opening with a slower ramp between input and output command can serve as an operational mode for entry level or experienced riders, such as the “limited” throttle mode depicted by the long-dash-short-dash line of
In the embodiment depicted, throttle input during the start-up period of T0 to T1 is relatively constant at TP0. During the first idle state period of time T1 to T2, throttle input is increased to TP1, which is an idle input. In an embodiment, during the start-up period and first idle period, throttle output may be predetermined, with little or no consideration of an actual throttle input so as to initialize operation of snowmobile 10 and engine 50 at start up. More specifically, and in this embodiment, from T0 to T2, all actual throttle positions TP for each available throttle mode may be substantially the same. In the embodiment of
After engine idle is established, and after time T2, throttle output is determined based on the position of throttle-input device 80 and a corresponding throttle-control translation map, e.g., the map for 1:1 map, or limited mode. As such, throttle output during time period T2 to T3 is referred to as “position-based” throttle control. Between time T2 and time T3, throttle input and throttle position TP corresponding to a 1:1 throttle-control translation map increases from throttle position TP1, to TP6 at time T3.
However, unlike the first set of throttle positions corresponding to selection of the 1:1 throttle map, when an operator selects the second or race map, electronic throttle-control system 88 and ECU 128 controls throttle valves 94 to exceed an operator-requested throttle input. For example, when throttle input is at approximately 50%, which in a 1:1 mapping would correspond to a 50% throttle output at throttle position TP4, the throttle output is approximately 75% at throttle position TP5. In other words, the throttle output at TP5 is 1.5 times the throttle input of TP4, i.e., a 1:1.5 translation. A difference between throttle outputs for throttle input/1:1 map as compared to the race map is measured as Δ1. In an embodiment, this throttle-output difference Δ1 may vary with throttle input, such that a non-linear relationship between throttle input and throttle output is defined by the second or race map, as depicted. As will be understood by those of ordinary skill, a relationship between throttle input and throttle output may be defined in many different ways by a throttle-control translational map.
Conversely, when an operator selects the third or limited map, electronic throttle-control system 88 and ECU 128 control throttle valves 94 to be below an operator-requested throttle input. For example, when throttle input is at approximately 50%, which in a 1:1 mapping would correspond to a 50% throttle output at throttle position TP4, the throttle output is approximately 35% at throttle position TP3. In other words, the throttle output at TP3 is 0.7 times the throttle input of TP4, i.e., a 1.33:1 translation. As can be seen by the long-dash-short-dash line corresponding to the third and limited translational map, throttle output is less than throttle input for most requested throttle inputs.
At time T3, throttle input is nearly at a maximum input, and throttle position demand is at TP6 for the given map selection. Shortly after time T3, throttle input is at maximum input, or 100%, and throttle-input device 80 is held by an operator at a mechanical stop. Throttle position TP is controlled by a fixed-duty cycle. From approximately time T3 to time T4, throttle control is no longer position based since the throttle input is at the maximum setting.
Rather, throttle control is now based on predetermined parameters saved in electronic throttle-control system 88, such as maximum throttle position TP7.
At time T4, throttle input is at a maximum and throttle position TP still at TP7. After time T4, throttle input decreases below a maximum throttle input based on operator control of throttle-input device 80, as sensed by throttle-input sensor 138, and as communicated to ECU 128. Consequently, from time T4 to time T5, throttle control is once again position based, i.e., based upon a position of throttle-input device 80.
At time T5, a second idle PID control loop is implemented, with throttle output TP being set to idle throttle output TP1.
Referring to the flow charts of
Referring specifically to the flow chart of
If generated voltage V is at or above the predetermined threshold voltage, then the power supplied by the stator is sufficiently high to provide the necessary current to throttle valve actuator 96 to ensure position accuracy and no loss of other vehicle function occurs due to voltage drops. Consequently, sufficient power will be available to continue the start-up process, then at step 206, actual engine speed ES, which may be measured in RPMs, is compared to a first predetermined engine-speed threshold, ES1. In an embodiment, engine speed is monitored by ECU 128, which receives input from engine-speed sensor 140 (see
If the engine speed ES is not above the predetermined engine-speed threshold ES1, then monitoring of engine speed ES continues.
After setting throttle position TP to a throttle start position, in an embodiment, electronic throttle-control system 88 initiates a timer hold sequence, such that at step 210 a timer is started. At step 212, if the tinier time is less than a predetermined hold time, then the timer hold sequence continues, then when the timer is equal to the predetermined hold time, at step 214, engine speed ES, which may be measured in RPM, is compared to a second predetermined engine-speed threshold, ES2. In an embodiment, second engine-speed threshold ES2 is greater than first engine-speed threshold ES1.
If engine speed ES is greater than second engine-speed threshold ES2, then at step 216, electronic throttle-control system 88 begins controlling throttle position TP in a “normal” operating mode, which may be a position-based operating mode as described above.
However, if engine speed ES is not greater than second engine-speed threshold ES2, then at step 218, electronic throttle-control system 88 decays or reduces that throttle position TP to close down valves 94 until engine speed ES increases, and electronic throttle-control system 88 begins controlling throttle position TP in a “normal” operating mode, which may be a position-based operating mode as described above.
Referring to the flow chart of
Referring specifically to
When the electronic throttle control (ETC) idle PID control loop is not enabled, then electronic throttle-control system 88 controls throttle valve actuator 96 and throttle valves 94 according to a fixed-state output based on a throttle-closed duty cycle. In other words, the throttle position is set to a fixed position which is substantially closed.
When the electronic throttle control (ETC) idle PID control loop is enabled, then after an idle control transition time, such as described at steps 210 and 212 of the method of
At step 246, when the ECU-demanded throttle position TP is not less than the predetermined idle throttle position and engine speed ES is not less than the predetermine engine-idle speed, then at 254, a throttle-control translation map (“throttle map”) is selected. As described above, a throttle map describes a relationship between a plurality of throttle-inputs and a plurality of corresponding throttle outputs. A throttle may be selected by an operator of snowmobile 10 interacting with operator inputs 120, which is them implemented by ECU 128, or may be selected by ECU 128 based on operator input, prior selected maps, a predetermined stored default throttle map, saved throttle-map selection history, and/or other factors.
At step 256, a throttle position TP1 is set by electronic throttle-control system 88 based at least in part on the selected throttle map.
At step 258, ECU 128 receives input from gear sensor 136 (see also,
At step 264, a series of faults are checked by ECU 128. If any faults are detected, then at step 266, throttle position TP is set to a predetermined throttle position setting based on the particular fault detected. ECU 128 may be configured to determine whether any of a number of faults relating to engine 50 or other snowmobile 10 systems have occurred. Such faults may include: low ECU voltage, low or high engine temperature, problematic spark/detonation, oil pump operation or pressure, unrealistic barometric pressure, unrealistic outside air temperature, high exhaust temperature, low fuel pressure, riding with brakes on, and other faults.
Referring also to
Otherwise, at step 272, ECU determines whether the vehicle ground speed is greater than a predetermined allowable ground speed. When the vehicle ground speed is greater than the predetermined allowable ground speed, then at step 274, ECU 128 and electronic throttle-control system 88 changes the throttle valve position to reduce air flow to achieve a target maximum allowable vehicle ground speed. In an embodiment, the target allowable vehicle ground speed may be controlled by an operator interacting with operator inputs 120, which may include gauge 166.
When the vehicle ground speed is not greater than the predetermined allowable ground speed, then at step 276, ECU 128 compares the current TPS Demand or throttle position TP to a throttle position maximum threshold. When the ECU demanded throttle position is greater than a maximum throttle position threshold. ECU 128 and electronic throttle-control system 88 controls the throttle according to a fixed state pout control based on a throttle-open duty cycle. In other words, when an operator actuates throttle-input device 80 to request maximum throttle, and ECU 128 determines a corresponding throttle position TP, if that demanded throttle position exceeds a predetermined maximum throttle position, then electronic throttle-control system 88 and ECU 128 set the throttle position according to a predetermined fixed position corresponding to an open position of throttle valves 94.
At step 280, when TPS Demand is not greater than the TPS Demand maximum threshold, then ECU 128 determines whether an actual throttle valve position detected by throttle-position sensor 142 is greater than the throttle position demanded or determined by ECU 128 plus a hysteresis factor, for a predetermined period of time, and also whether a throttle-safety switch is active for a predetermined period of time. If yes, this indicates a fault in engine throttle control, such as a throttle valve 94 being stuck in an open position, and fuel and engine ignition are cut so as to cease operation of engine 50.
Referring also to
When ECU 128 does not detect the safety switch conditions of step 284, then at step 288, another check by ECU 128 is conducted. At step 288, ECU 128 determines whether engine speed ES is above a predetermined maximum engine speed. If it is, then at step 290, ECU 128 and electronic throttle-control system 288 reduces throttle, i.e., changes a throttle position TP to reduce air flow, so as to achieve the predetermined target maximum engine speed.
When engine speed ES is not above the predetermined maximum engine speed, then at step 292, ECU 128 determines whether the demanded throttle position is greater than an allowable maximum throttle demand. If not, at step 296, the throttle demanded or throttle position TP determined by ECU 128 is left unchanged. However, if the demanded throttle position is above the maximum, then at step 294, electronic throttle-control system 88 controls and reduces the throttle position such that the throttle position corresponds to the predetermine maximum throttle position.
Following either of steps 294 or 296, the process reverts to step 256 (
Referring to
As will be understood by one of ordinary skill, engine-idle speed is the process variable to be measured and controlled. Consequently, engine-idle speed target or set-point value 356, which may be defined in engine RPM, is input into comparator 354. Actual or sensed engine-speed is also input into comparator 354, although initially, a first or initial engine-idle speed at step 358 is input for the first calculation. In an embodiment, sensed engine-idle speed at step 356 is transmitted from engine-speed sensor 140 and received by ECU 128 for processing as part of the idle PID control loop.
Comparator 354 compares sensed engine-idle speed with the target engine-idle speed 352, and outputs engine-idle speed error 360. The function of comparator 354 may be performed by a processor of ECU 128, as will be understood by one of ordinary skill in the art.
Proportional, integral and differential gains 362, 364 and 366 are determined based on the respective proportional, integral and differential components of error 360, then summed at step 368 to determine a corrected throttle position at step 370 which is intended to achieve the target engine-idle speed. At step 372, the corrected throttle position is compared to a maximum idle throttle position.
At step 374, when the corrected throttle position is greater than a predetermined throttle position that achieves a maximum engine-idle speed, then the throttle position is set to the throttle position to cause maximum engine-idle speed in ECU 128, and electronic throttle-control system 88 adjusts a throttle position to the throttle position to achieve maximum engine-idle speed.
At step 376, when the corrected throttle position is not greater than a predetermined throttle position that achieves a maximum engine-idle speed, then the throttle position remains set to the corrected throttle position and electronic throttle-control system 88 adjusts a throttle position to the corrected throttle position.
Engine-speed is checked again at step 356, and analyzed by comparator 354, and the loop analysis is repeated.
The following clauses illustrate the subject matter described herein.
Clause 1. An electronic throttle control system that includes: an electronic control unit (ECU) including a processor and a memory device storing at least one throttle-control translation map; a throttle-input sensor in electrical communication with the ECU and configured to sense an input from an operator-actuated throttle device; and a 2-stroke internal-combustion engine. The 2-stroke internal-combustion engine may include: an electronic throttle-valve actuator in electrical connection with the ECU and having an actuator motor and gear train; a throttle body for controlling airflow to one or more combustion chambers of the 2-stroke internal-combustion engine, the throttle body defining a first throttle bore and a second throttle bore; a first throttle valve in the first throttle bore and a second throttle valve in the second throttle bore; and a throttle valve control shaft coupled to the first throttle valve and the second throttle valve, and to the gear train, such that movement of the actuator motor and gear train causes the throttle valve control shaft to rotate and move the first and second throttle valves; a throttle-position sensor in electrical communication with the ECU and configured to sense an actual position of the first and second throttle valves. Further, the ECU may be configured to receive a signal representing a throttle-position input from the throttle-input sensor and to determine a throttle-demand position corresponding to a position of the first throttle valve in the first throttle bore and a position of the second throttle valve in the second throttle bore, based on the throttle-position input and throttle-control translation map.
Clause 2. The electronic throttle control system of clause 1, further comprising an engine-speed sensor in electrical communication with the ECU and configured to sense a speed of the 2-stroke internal-combustion engine.
Clause 3. The electronic throttle control system of clause 2, wherein the ECU is configured to control the actuator during a start mode to decrease the throttle output when a sensed speed of the 2-stroke internal-combustion engine is less than an engine-speed threshold.
Clause 4. The electronic throttle control system of clause 1, wherein the ECU is configured to limit a throttle-demand position based on ground speed, engine speed, and/or user-selected limit parameters or fault-state limit positions.
Clause 5. The electronic throttle control system of clause 1, wherein a bore diameter of the first throttle bore is substantially the same as a bore diameter of the second throttle bore and a throttle-bore pitch of the first throttle bore to the second throttle bore is greater than twice the bore diameter.
Clause 6. The electronic throttle control system of clause 5, wherein the bore pitch is in a range of 100 mm to 200 mm.
Clause 7. The electronic throttle control system of clause 6, wherein the bore pitch is in a range of 130 mm to 140 mm.
Clause 8. A snowmobile, comprising the electronic throttle control system of any of clauses 1-7.
Clause 9. Another embodiment of the disclosure is a method of controlling a starting mode of snowmobile having an electronic-control unit (ECU) with a processor, and a 2-stroke combustion engine with an electronic throttle body having a first throttle valve, a second throttle valve, a throttle-position sensor, and an actuator for actuating the first and second throttle valves. The method includes the steps of: determining whether an electronic throttle body drive-voltage generated by the 2-stroke combustion engine is above a threshold voltage; determining whether an engine speed of the 2-stroke combustion engine is above a first engine-speed threshold; when the generated voltage is at or above the critical threshold voltage and the speed of the 2-stroke combustion engine is above a threshold engine-speed threshold, setting a throttle position of the first throttle valve and the second throttle valve to a neutral-throttle position: after a predetermined period of time, determine whether the engine speed is greater than a second engine-speed threshold; and when the engine speed is greater than the second engine-speed threshold, changing a position of the first throttle valve and the second throttle valve from the neutral-throttle position to an initial throttle-operating position, by controlling the actuator with the processor of the ECU.
Clause 10. The method of clause 9, further comprising initializing the processor of the ECU.
Clause 11. The method of clause 9, wherein in the neutral-throttle position, an effective area of each of the first throttle valve and the second throttle valve is greater than a respective effective area of the first throttle valve and the second throttle valve in the initial throttle-operating position.
Clause 12. The method of clause 11, further comprising setting a position of the first throttle valve and the second throttle valve to the neutral-throttle position using a spring to bias the first and second throttle valves.
Clause 13. The method of clause 12, wherein changing a position of the first throttle valve and the second throttle valve from the neutral position to an initial throttle-operating position comprises the processor controlling the actuator to move the first throttle valve and the second throttle valve to the initial throttle-operating position in opposition to a force exerted by the biasing spring.
Clause 14. The method of clause 9, wherein in the neutral-throttle position, an effective area of each of the first throttle valve and the second throttle valve is less than a respective effective area of each of the first throttle valve and the second throttle valve in the initial throttle-operating position, and changing a position of the first throttle valve and the second throttle valve from the neutral-throttle position to the initial throttle-operating position includes further increasing the effective area of the first throttle valve and the second throttle valve while the voltage is increasing and below the critical voltage threshold.
Clause 15. Yet another embodiment of the disclosure includes a method of controlling a snowmobile having an electronic-control unit (ECU) with a processor, a memory storing one or more throttle-control translation maps, and a 2-stroke combustion engine with an electronic throttle body having a first throttle valve, a second throttle valve, a throttle-position sensor, an actuator for actuating the first and second throttle valves, and an engine-speed sensor. In this embodiment, the method includes: storing a predetermined idle-speed throttle-valve position and the one or more throttle-control translation maps in the memory; determining with the ECU a throttle-demand valve position, the throttle-demand valve position corresponding to a throttle-demand valve effective area of the first and second throttle valves; comparing the throttle-demand valve position to the predetermined idle-speed throttle-valve position; receiving at the ECU, an output of the engine-speed sensor indicating an actual engine speed of the 2-stroke internal-combustion engine; comparing the actual engine speed with a predetermined engine-idle speed; selecting a throttle-control translation map stored in the memory when the throttle-demand position effective flow area is greater than the predetermined idle-speed throttle position effective flow area and when the actual engine speed is greater than the predetermined idle engine speed; controlling the actuator using the ECU to set a first position of the first throttle valve in the first throttle bore and a first position of the second throttle valve in the second throttle bore based on the selected throttle-control translation map: determining whether an engine fault is present and controlling the actuator using the ECU to set a second position of the first throttle valve in the first throttle bore and a second position of the second throttle valve in the second throttle bore when a fault is present; and determining whether a ground speed or engine speed exceeds a maximum speed limit and controlling the actuator using the ECU to set a third position of the first throttle valve in the first throttle bore and a third position of the second throttle valve in the second throttle bore to reduce ground speed or engine speed to be less than the maximum speed limit.
Clause 16. The method of clause 15, further comprising controlling the first and second throttle valves to maintain an engine idle speed when the throttle-demand position effective flow area is less than the predetermined idle-speed throttle position effective flow area and when the actual engine speed is less than the predetermined idle engine speed.
Clause 17. The method of clause 15, further comprising determining whether a gear position of the snowmobile is a low-gear position, and setting a position of the first and second throttle valves to a low-gear throttle position when the gear position of the snowmobile is a low-gear position.
Clause 18. The method of clause 15, further comprising setting a position of the first and second throttle valves to a fixed-state throttle position when a throttle-demand effective flow area exceeds a throttle-demand maximum threshold.
Clause 19. The method of clause 15, further comprising comparing an actual throttle position of the first and second throttle valves as indicated by the throttle-position sensor to a throttle-demand position, and causing the ECU to cease engine fuel flow and/or ignition when the actual throttle position effective flow area is greater than the throttle-demand position effective flow area for a predetermined period of time.
Clause 20. The method of clause 15, further comprising determining, when the snowmobile includes a safety switch, that the safety switch is active for greater than a predetermined period of time, and in response, causing the ECU to cease engine fuel injection and/or ignition.
Clause 21. The electronic throttle control system of clause 1, wherein the bore diameter is in a range of about 40 mm to about 60 mm.
The embodiments above are intended to be illustrative and not limiting. Additional embodiments are within the claims. In addition, although aspects of the present invention have been described with reference to particular embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention, as defined by the claims.
Persons of ordinary skill in the relevant arts will recognize that the invention may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not meant to be an exhaustive presentation of the ways in which the various features of the invention may be combined. Accordingly, the embodiments are not mutually exclusive combinations of features; rather, the invention may comprise a combination of different individual features selected from different individual embodiments, as understood by persons of ordinary skill in the art.
Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.
For purposes of interpreting the claims for the present invention, it is expressly intended that the provisions of Section 112, sixth paragraph of 35 U.S.C. are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.
This application claims the benefit of U.S. Provisional Patent Application No. 63/583,312 filed Sep. 18, 2023, entitled ELECTRONIC THROTTLE CONTROL OF SNOWMOBILE WITH TWO-STROKE INTERNAL-COMBUSTION ENGINE, the contents of which are expressly incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63583312 | Sep 2023 | US |
