Patent Publication Number: US-2020300206-A1

Title: Outdoor power equipment with electronic start

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/574,167, filed Oct. 18, 2017, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     The present disclosure relates to outdoor power equipment with an electrical starting motor and associated controls. More specifically, the present disclosure relates to an internal combustion engine having an electrical starting motor for starting the internal combustion engine. 
     Presently, many different types of outdoor power equipment include electronic starting circuits that allow the user to start the internal combustion engine of the outdoor power equipment through either a key switch or a push button. However, this often requires additional wiring and/or controls to be added to the outdoor power equipment. This can create additional cost and complexity when adding an internal combustion motor with electronic start to various outdoor power equipment applications. 
     SUMMARY 
     The present disclosure relates to systems and methods for starting an internal combustion motor associated with outdoor power equipment, as described in the embodiments listed herein. 
     One embodiment of the invention relates to a lawn mower. The lawn mower includes an internal combustion engine, and an electric motor configured to start the internal combustion engine. The lawn mower further includes a brake mechanism and a release mechanism movable to an engaged position to release the brake mechanism. The lawn mower further includes a switch actuation by, the release mechanism, a pull rope, and a sensor configured to output a signal based on the pull rope being actuated. The lawn mower further includes a control module coupled to the switch and the sensor, wherein the switch is configured to provide inputs to the control module when the release mechanism is in the engaged position, and the sensor is configured to provide an input to the control module when the pull rope is actuated, and wherein the control module turns on the electric motor in response to the signals from the sensor and the switch. 
     Another embodiment of the invention relates to outdoor power equipment. The outdoor power equipment includes an internal combustion engine, an electric motor configured to start the internal combustion engine, and an implement driven by the internal combustion engine. The outdoor power equipment further includes a release mechanism movable to an engaged position to put the implement in a ready-to-run condition in which the implement is ready to be driven by the internal combustion engine. The outdoor power equipment further includes a switch actuated by the release mechanism and a sensor configured to detect actuation of a manual starting mechanism. The outdoor power equipment further includes a control module coupled to the switch and the sensor so that the switch provides a signal to the control module when release mechanism is in the engaged position, and the sensor provides a signal indicating actuation of the manual starting mechanism. The control module is further configured to turn on the electric motor to start the internal combustion engine in response to the signal from the switch and the sensor both being provided to the control module. 
     Another embodiment of the invention relates to a method of starting an internal combustion engine. The method includes receiving a first signal at a control module indicating that a release mechanism has been actuated and receiving a second signal at the control module indicating that a pull rope of the internal combustion engine has been pulled by at least a predetermined distance. The method further includes energizing an electric starting motor to start the internal combustion engine based on receiving the second signal after the first signal has been received, and where the first signal is still present at the control module when the second signal is received by the control module. 
     Another embodiment of the invention relates to a method of starting an internal combustion engine. The method includes detecting movement of a starter rope coupled to the internal combustion engine, detecting the status of an operator presence sensor, and activating an electric starter motor selectively coupled to the internal combustion engine based on receiving the second signal after the first signal has been received, and where the first signal is still present at the control module when the second signal is received by the control module. 
     Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, in which: 
         FIG. 1  illustrates a piece of outdoor power equipment in the form of a lawn mower, according to an exemplary embodiment; 
         FIG. 2  is a block diagram of a starting system associated with an internal combustion engine, according to some embodiments; 
         FIG. 3  is a top view of a rewind assembly including a pull rope sensor, according to some embodiments; 
         FIG. 4  is an electrical schematic illustrating a pull rope sensor latching circuit, according to some embodiments; 
         FIG. 5  is an electrical schematic illustrating a starting control system of an internal combustion engine, according to some embodiments; and 
         FIG. 6  is a flow chart illustrating a process for starting an internal combustion engine, according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to a starting system for an internal combustion engine used with various types of outdoor power equipment. The drawing figures depict the use of the intelligent battery pack with a lawn mower. However, it should be understood that the battery pack and starting system could be utilized with other types of outdoor power equipment such as riding tractors, snow throwers, pressure washers, tillers, log splitters, zero-turn radius mowers, walk-behind mowers, riding mowers, stand-on mowers, pavement surface preparation devices, industrial vehicles such as forklifts, utility vehicles, commercial turf equipment such as blowers, vacuums, debris loaders, over-seeders, power rakes, aerators, sod cutters, brush mowers, sprayers, spreaders, etc. 
       FIG. 1  illustrates a piece of outdoor power equipment, in the form of a lawn mower  110 , which includes an internal combustion engine  112  coupled to a rotary tool, such as the blade in a deck of the lawn mower  110 , an auger, a saw, tines, a drill, a pump, or other rotary tools. In some embodiments, the lawn mower  110  further includes wheels  116  and a rearward extending handle  118  designed to be pushed by an operator walking behind the lawnmower  110 . In other contemplated embodiments, the outdoor power equipment may be in the form of a rotary tiller, a pressure washer, a snow thrower, a lawn tractor or riding mower, an edger, a portable generator, or other equipment, with a corresponding powered tool, such as tines, a pump, an auger and impeller, an alternator, a drive train, or other tools. 
     Still referring to  FIG. 1 , the lawn mower  110  includes a starter system. According to one embodiment, the starter system includes an electric motor  120  that is selectively coupled to the engine  112  such that the electric motor  120  is configured to rotate the crankshaft of the engine  112  to start the engine  112  and is configured to disengage once the engine  112  is running (e.g. operating above a predetermined RPM). In some embodiments, the motor  120  is fastened to the engine  112 , such as being mounted on top of or to a side of the engine  112 . Gearing (e.g. gear reduction, transmission, etc.) may extend between the motor  120  and the crankshaft of the engine  112 , or the motor may be connected directly to the crankshaft of the engine  112 . The starter system may further include a battery and a control module, which will be described in more detail below. The lawnmower  110  may further include a pull rope  125 . The pull rope  125  may be coupled to a rewind assembly of the lawnmower  110 , which in turn may be coupled to crankshaft of the engine  110 , such that when an operator pulls the pull rope, motion is imparted to the crankshaft to facilitate starting of the engine  112 . 
     In some embodiments, the starter system is integrated with a bail  126  of the lawn mower  110 . A brake mechanism (e.g., friction brake, ignition interrupt switch or circuit, etc.) may be holding the blade or other tool, locking the crankshaft of the engine  112 , or otherwise preventing operation of the power equipment. As such, releasing of the brake mechanism eases operation of the lawn mower  110  or other outdoor power equipment by reducing the steps necessary for activation. Furthermore. and as will be discussed in more detail below, a second input, such as actuation of the pull rope  125  may further be used to start the engine  112 , in combination with the actuation of the bail 
     In general, integration of the starter system with a handle of outdoor power equipment allows the operator to start the engine from the rear of the outdoor power equipment, such as several feet from the powered tool of the outdoor power equipment (e.g. snow thrower auger, lawn mower blades). Further, the integration supports an electronic starting system for a walk behind mower that can be engage by a user without actuation of a key or push-button. 
     According to some embodiments, the starter system further includes an energy storage device  130  (e.g. a battery, capacitor, etc.) and a controller  132 , The energy storage device  130  may include one or more batteries (e.g. lead acid, NiCd, Li-Ion, etc.), capacitors (e.g. super capacitors), or other devices. The batteries may be removable batteries. In some embodiments, the batteries may be power tool batteries configured to be received in a receiver mounted to the internal combustion engine  112  or the lawn mower  110 . In one embodiment, the energy storage device  130  may be located on the internal combustion engine  112 . In other embodiments, the energy storage device  130  may be located on the lawn mower  110 . When the operator engages the starter system, the linkage  124  communicates one input to controller  132 , either directly or indirectly. Similarly, and as will be discussed in more detail below, a second input signal may be provided to the controller  132 , either directly or indirectly, when the user further engages the pull rope  125 . The controller may then electrically connect the energy storage device  130  to power the starter motor  120 . In some embodiments, the controller  132  is further coupled to one or more sensors within the engine  112  (e.g. a speed sensor, an ignition sensor, etc.), and may be configured to disengage the motor  120  (e.g. cuts power to the motor  120  via high-side switching of the electrical power source  130 , and/or low-side switching of the ground or common side of the electrical power source  130 ) when it is determined by the controller  132  that the engine  112  is running at a sufficient speed. 
     In some embodiments, the motor  120 , the energy storage device  130 , and the controller  132  are fastened directly to the engine  112 , which may be configured for efficient assembly of outdoor power equipment using the engine  112 . As such, the starter system in some embodiments may come fully assembled with the engine  112 , and ready for connection to a linkage configured to provide a signal from the handle (e.g., linkage  124 ). Accordingly, the manufacturer need only attach the engine  112  to the deck or corresponding feature and attach the tool to the power takeoff of the engine. In any such case, considerable time and effort may be saved during the manufacturing process and a potential source of manufacturing difficulty may be removed (i.e., that associated with the fastening and electrical connection of the components of the starter system during assembly of the outdoor power equipment). In still other embodiments, some or all of the starter assembly may be fastened to the deck of a lawn mower or corresponding feature of other power equipment. 
     Referring to  FIG. 2 , outdoor power equipment  200  (shown schematically) includes an engine  202  and a powered tool  204  (e.g. a rotary blade) driven by the engine  202 . In some embodiments, a motor  206  is coupled to the engine  202 , and the powered tool  204  is coupled to a power takeoff  208  of the engine. A speed sensor  210  (e.g., governor) may be coupled to the engine  202  to regulate the speed of the engine  202 . Also, a brake  212  may be coupled to a rotary member of the outdoor power equipment  200 , such as the flywheel of the engine  202 , the power takeoff  208  of the engine  202 , etc., to stop the engine as well as the associated power tool  204 . 
     In some embodiments, the outdoor power equipment  200  includes a handle  214  having a release mechanism  216 , where the release mechanism  216  is configured to allow a user to release the brake  212  from the handle  214 . The release mechanism  216  may allow a user to release the brake  212  by engaging the bail (or other element) with a linkage connected to the brake  212 , or by disengaging an element blocking movement of the bail. The handle  214  may be coupled to the engine  202  and tool  204  directly, or via an intermediary member (e.g., deck  114  as shown in  FIG. 1 ). The engine  202  may further include a battery  218  for powering the motor  206  and a control system  220  for operating the motor  206 . 
     According to one embodiment, the outdoor power equipment  200  may further include a pull rope sensor  222 . The pull rope sensor  222  is configured, to monitor a movement of the pull rope (e.g. pull rope  125  in  FIG. 1 ). The pull rope sensor  222  may further be configured to provide an input to the control system  220  indicating that the operator has actuated the pull rope. In some embodiments, the pull rope sensor  222  may be configured to provide an input to the control system  220  when the pull rope is actuated by a predetermined or minimal amount. For example, in some embodiments, the operator may only need to pull the pull rope approximately four inches for the pull rope sensor  222  to register movement of the pull rope and provide a signal to the control system  220 . However, other pull lengths of more than four inches or less than four inches are also contemplated. For example, other pull lengths may include a length of less than two feet, less than one foot, or less than six inches. However, other pull lengths are contemplated. By only requiring the operator to pull the pull rope a minimal fraction of a normal pull start engine, the operator is not required pull the pull rope as in a normal pull-start based engine. In some embodiments, a visual indicator, such as color stripes, tape, text or other visual markings may provide an indication to the operator as to the exact amount of pull of the pull rope needed to start the internal combustion engine  202 . 
     In some embodiments, the pull rope sensor  222  may be a hall effect sensor. The hall effect sensor may be configured to detect the passing of one or more magnets on a rewind assembly. Thus, when the operator pulls the pull rope, causing the rewind assembly to rotate, thereby passing the one or more magnets within the fixed position of the hall effect sensor. In some embodiments, the one or more magnets may be embedded into the rewind assembly. 
     Turning to  FIG. 3 , a photograph illustrating, an example implementation of the above hall effect sensor assembly is shown, according to some embodiments. Shown in  FIG. 3  is a rewind assembly  300  associated with a pull start mechanism of an internal combustion engine. A hall effect sensor  302  is attached in a stationary position on a housing  304  of the rewind assembly  300 . A magnet  306  is attached to a rotating portion  308  of the rewind assembly  300 . When an operator actuates (e.g. pulls) a pull rope  310 , the rotating portion  308  of the rewind assembly is caused to rotate, thereby passing the magnet  306  by the hall effect sensor  302 . The hall effect sensor  302  may then generate a signal which can be provide to a control system, such as control system  220 . While the system in  FIG. 3  is shown with only a single magnet  306 , it is contemplated that multiple magnets could be installed onto the rotating portion  308  of the rewind assembly  300  to reduce the amount that the operator would have to pull the pull rope  310 . In other embodiments, a magnet ring, having magnets of alternating polarity may be installed onto the rotating portion  308  of the rewind assembly  310 . The hall effect sensor  302  may then detect a change in polarity as the magnets pass by and send a corresponding signal to a control system. 
     While  FIG. 3  illustrates one embodiment wherein a magnet and hall effect sensor are used to generate a signal to the control system, other methods and system are also contemplated. For example, in one embodiment, one or more contact switches may be placed within the rewind assembly such that when the rotating portion moves due to an operator actuating the pull rope  310 . For example, contact sensors may be placed on one or more contact surfaces within the rewind assembly that come into contact during rotation of the rewind assembly. In other examples, an optical sensor may be used to determine that the pull rope has been actuated. For example, an optical sensor may be placed in a location similar to that of the hall effect sensor  302 . The optical sensor may then detect movement of the rotating portion  308  of the rewind assembly  300 . In some embodiments, optical markings, such as alternating black and white colors, may be located on the rotating portion  308  of the rewind assembly  300  to provide an indication to the optical sensor that the pull rope  310  has been actuated (e.g. the optical sensor can detect the change in colors as the rotating portion  308  rotates. 
     In other embodiments, an optical sensor may be positioned to detect a movement of the pull rope  310 . For example, the pull rope  310  may be configured to have an alternating color pattern which can be detected by the optical sensor. Optical sensors may include, photodiodes, photoelectric sensors, image sensors, optical switches, camera (e.g. CCD, CMOS, etc.) sensors, or other applicable optical sensors. In other embodiments, a magnet may be embedded in the pull rope  308 . The pull rope may then be configured to run through an aperture which can detect the magnetic field and provide a signal to the control system. Other sensors or devices, such as switches, pressure sensors, centrifugal motion sensors, infrared sensors, time of flight sensors, and/or other sensors which can detect a pull of the pull rope by the operator. 
     Returning now to  FIG. 2 , it is contemplated that in one embodiment, the control system  220  associated with the starter system is configured to receive inputs associated with the release mechanism  216  and the pull rope sensor  222 . In some embodiments, when the release mechanism  216  is actuated to release the brake  208 , the release mechanism  216  triggers a switch  224 , which provides an input to the control system  220  that is indicative of the release of the brake  212 , The signal may be provided via a mechanical linkage, wirelessly, a hardwired electrical connection, or otherwise. Once the operator has engaged the release mechanism  216 , the operator may then pull a pull rope by an amount such that the pull rope sensor  222  detects the actuation of the pull rope, as described above. The pull rope sensor may then provide an input to the control system  220  indicating that the operator has actuated the pull rope. In some embodiments, the control system  220  may then actuate the motor  206  to start the engine  202  or uses the information in control logic configured to start the engine as a function of the status of the release mechanism  216  and the pull rope sensor  222 . Thus, the operator may be able to start the engine  202  by actuating the release mechanism  216  and then pulling the pull rope by an amount to actuate the pull rope sensor  222 . 
     According to some embodiments, the control system  220  is configured to receive additional inputs from the speed sensor  210  or another component of the engine  112  (e.g., the ignition circuit). The speed sensor  210  or other component provides the control system  222  with information associated with the speed of the engine  112 . When the engine  112  is running at a sufficient speed, the control system  222  then disengages the motor  206  (e.g., turns off, disconnects, cuts power to, etc.). 
     In further embodiments, the control system  222  associated with the start system may receive additional or different inputs used to control starting of the engine, such as, input from a sensor configured to indicate whether the outdoor power equipment has moved recently. Movement of an axle or wheels of such outdoor power equipment may trigger a sensor that provides a signal to the control system. The signal, in combination with an electric timer providing time-related context for the movement, may serve as an additional indicator that the operator intends to activate the engine  202 . In other embodiments, the control system  222  in includes a tinier and is configured to deactivate the motor  206  if the engine has not started within a predetermined amount of time. In some contemplated embodiments, the control system  222  includes a temperature sensor and is configured to prime the engine with an automated primer pump or adjust the choke or throttle plate if ambient temperature is above or below a predetermined temperature, if a portion of the engine is above or below a predetermined temperature, or if the difference between ambient and engine temperature is above or below a predetermined, value. In still other embodiments, the control system  222  may also provide a signal output to the operator, such as a visible indicator on a display coupled to the handle or engine, or an audible alert. In some embodiments, the signal output may include an error message, a low-fuel message, a replace-oil message, or another such message. 
     In some embodiments, a motor, such as motor  206  may be configured to assist the operator in actuating the pull rope. For example, when actuation of the pull rope is detected, as described above, the motor  206  may be configured to actuate to provide additional force to the crank shaft, thereby reducing the effort required by the operator pulling the pull rope. This can allow for a smaller staring motor and associated battery to be used, while still increasing the ease of starting the outdoor equipment. 
     According to some embodiments, the circuits of  FIGS. 4 and 5  are contained on circuit boards that are integrated with the engine (see, e.g., controller  132  as shown in  FIG. 1 ), and may be fully powered by the battery or other on-board source. Accordingly, the circuits may require no electrical interface to components of the lawn mower or other outdoor power equipment aside from those carried by or integrated with the engine. No additional wiring or connections may be required. Accordingly, the assembly process for the associated outdoor power equipment may be improved, as discussed above. 
     Turning now to  FIG. 6 , a process  600  for starting an internal combustion engine coupled to an outdoor power equipment is shown, according to some embodiments. At process block  602 , an operator actuates a release mechanism (e.g. a bail) on the outdoor power equipment, at process block  604 , it is determined whether the release mechanism actuation signal is active (e.g. has the release mechanism been actuated). In some embodiments, the release mechanism actuation signal may be provided to a control system (e.g. control, system  222 ) as described above. If the release mechanism activation signal is not active, the process returns to process block  602  to await actuation of the release mechanism. If the release mechanism activation signal is active, the pull rope is actuated at process block  606 . For example, once an operator has actuated the release mechanism, the operator may then actuate (e.g. pull) the pull rope. The process then determines if the pull rope signal is received by the control system at process block  608 . The pull rope signal may be generated and provided to a control system as described above. If the pull rope signal is not received, the process returns to process step  606  to monitor for the pull rope signal to be received. If the pull rope signal is determined to be received at process block  608 , it is determined if the bail activation signal is still active at process block  610 . If the release mechanism activation signal is no longer active, the process returns to process block  602  to monitor for activation of the release mechanism. 
     If the release mechanism activation signal is determined to still be active at process block  610 , the starter motor is energized at process block  612 . At process block  614  the process determines if a minimum speed of the engine has been reached. In one embodiment, the minimum speed may be 1000 RPM. However, minimum speed values of more than 1000 RPM or less than 1000 RPM are also contemplated. If the minimum speeds have been reached, the starter motor is stopped at process block  616 , as described above. If the minimum speed is determined to not have been reached at process block  614 , the system then determines if a timer has expired at process block  618 . In one embodiment, the timer may be five seconds. However, in other embodiments, the timer may be more than five seconds or less than five seconds, as applicable. In some examples, the timer value is determined based on a rating of the starting motor and/or battery. If the timer is determined not to have expired, the process returns to process block  614 . 
     This written description uses examples to disclose the invention, including the best mode and to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 
     The construction and arrangement of the apparatus, systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, some elements shown as integrally formed may be constructed from multiple parts or elements, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.