Abstract:
A power module is connected to the starter, alternator, and battery for an internal combustion engine. The power module includes one or more capacitors and delay timer. When the ignition switch closes, the battery of the starting system provides current to the starter motor, causing the starter solenoid to close the starter contacts, and bring a starter pinion gear into engagement with a flywheel ring gear. The delay timer does not allow the capacitor to immediately deliver current to the starter motor, but implements a short delay before the capacitor&#39;s current is released to the starter motor. This short delay increases the chance for full engagement between the starter pinion and the flywheel ring gear, thereby reducing the likelihood of milling when the starter motor provides torque to the starter pinion.

Description:
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/519,052, filed Nov. 11, 2003, the disclosure of which is incorporated by reference. 
    
    
     BACKGROUND 
     In a typical motor vehicle having an internal combustion engine and an electric starter motor according to the prior art, the operator of the vehicle cranks the engine by turning a key or pressing a button that closes an ignition switch. When the ignition switch closes, electric current is provided to the windings of an electric starter motor solenoid. Upon excitation of the solenoid, a plunger rod carried within the solenoid is caused to move in a linear direction. A linking rod connects one end of the plunger rod to the starter motor&#39;s pinion gear drive shaft. As the plunger rod moves, it causes the linking rod to rotate about a pivot point. Rotation of the linking rod about the pivot point moves the pinion gear drive shaft in a linear direction toward the flywheel ring gear of the motor vehicle engine. 
     Upon reaching the ring gear, the teeth of the pinion gear are designed to mesh with the teeth of the ring gear. To encourage full engagement of the pinion gear teeth and the ring gear, a small amount of axial rotation may be provided to the pinion gear as it moves toward the ring gear. Such rotation may be imparted, for example, with a helical spline gear positioned on the drive shaft of the electrical motor. The starter motor contacts then are closed and electric current is provided to the windings of the electric motor, causing the drive shaft of the electric motor to rotate the pinion gear. If the pinion gear teeth are engaged with the ring gear, rotation of the drive shaft and pinion gear causes the ring gear to rotate and crank the automobile engine. 
     A problem exists in with such a prior art starter motor. When the starter motor contacts are closed, a high inrush current from the battery or other power storage device causes the rotation of the starter motor drive shaft and pinion gear to accelerate rapidly. If there is any misalignment between the teeth of the pinion gear and the teeth of the ring gear, the pinion gear and ring gear may abut instead of meshing together. The rotation of the pinion gear may encourage the teeth to engage, but this too often is not the case if the pinion gear immediately begins rotating at a high rate. Instead, if the pinion gear teeth and the ring gear teeth are not enmeshed deeply enough when the electric motor transmits torque through the starter motor drive shaft, the pinion gear teeth can mill against the ring gear teeth rather than starting the engine. This also can cause damage to the starter motor and the ring gear. 
     Accordingly, it would be desirable to provide an anti-milling system for automotive starters. Such a system will promote the full engagement of the teeth of the starter motor pinion gear and the teeth of the ring gear prior to the acceleration of the starter motor drive shaft. 
     SUMMARY 
     In an embodiment, the present invention comprises a starting system for an internal combustion engine. The starting system of this embodiment comprises a battery, an electric starter motor, a first switch operable to make and break an electrical connection between the battery and the electric starter motor, means for storing an electric charge, a second switch operable to make and break an electrical connection between the electric starter motor and the means for storing an electric charge, and a sensor operable to detect a predetermined electrical parameter in the electrical connection between the battery and the electric starter motor and to transmit a signal actuating the second switch. In an aspect of this embodiment, the signal actuating the second switch comprises a control signal causing the second switch to make an electrical connection between the electric starter motor and the means for storing an electric charge, where the control signal is transmitted a predetermined time after the predetermined electrical parameter is detected. In an aspect of this embodiment, the signal actuating the second switch comprises a control signal causing the second switch to break an electrical connection between the electric starter motor and the means for storing an electric charge, where the control signal is transmitted a predetermined time after the predetermined electrical parameter is detected. In an aspect of this embodiment, the means for storing an electric charge is one or more capacitors and/or one or more batteries. 
     In an embodiment, the present invention comprises a starting system for an internal combustion engine. The starting system for an internal combustion engine of this embodiment comprises an electric starter motor, a battery electrically connected to the electric starter motor via a switched connected, and a unitary control module. The unitary control module of this embodiment comprises a housing, means for storing an electric charge disposed within the housing, a sensor disposed within the housing, and a switch disposed within the housing. The sensor is operable to detect a predetermined electrical parameter in the switched electrical connection between the electric starter motor and the battery. The switch is operable to make and break an electrical connection between the means for storing an electric charge and the starter motor in response to a signal from the sensor. In an aspect of this embodiment, the signal comprises a control signal causing the switch to make an electrical connection between the starter motor and the means for storing an electric charge, where the control signal is transmitted a predetermined time after the predetermined electrical parameter is detected. In an aspect of this embodiment, the signal comprises a control signal causing the switch to break an electrical connection between the electric starter motor and the means for storing an electric charge, where the control signal is transmitted a predetermined time after the predetermined electrical parameter is detected. In an aspect of this embodiment, the means for storing an electric charge is one or more capacitors and/or one or more batteries. 
     In an embodiment, the present invention comprises a starting system for an internal combustion engine. The starting system of this embodiment comprises a battery having a positive terminal and a negative terminal, an electric starter motor, a first switch operable to make and break a electrical connection between the battery and the electric starter motor, means for storing an electric charge having a positive lead and a negative lead, and a current limiting device. The current limiting device is electrically connected between the positive lead of the means for storing an electric charge and the electric starter motor. The current limiting device is operable to permit pulses of direct current to flow from the positive lead of the means for storing an electric charge to the electric starter motor. In an aspect of this embodiment, the means for storing an electric charge is one or more capacitors and/or one or more batteries. 
     In an embodiment, the present invention comprises a starting system for an internal combustion engine. The starting system of this embodiment comprises a battery, an electric starter motor comprising a moveable pinion gear drive shaft, a first switch operable to make and break an electrical connection between the battery and the electric starter motor, means for storing an electric charge, a second switch operable to make and break an electrical connection between the electric starter motor and the means for storing an electric charge, and a sensor operable to actuate the second switch upon detecting that the moveable pinion gear drive shaft is in a predetermined position. In an aspect of this embodiment, the means for storing an electric charge is one or more capacitors and/or one or more batteries. 
     In an embodiment, the present invention comprises a starting system for an internal combustion engine. The starting system of this embodiment comprises a battery having a positive terminal and a negative terminal, an electric starter motor, a first switch operable to make and break a electrical connection between the battery and the electric starter motor, and a current boosting device electrically connected between the positive terminal of the battery and the electric starter motor. The current boosting device of this embodiment is operable to enhance the cranking current provided to the electric starter motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of this invention, and the methods of obtaining them, will be more apparent and better understood by reference to the following descriptions of embodiments of the invention, taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic diagram showing an engine starting motor anti-milling device according to an embodiment of the present invention connected to other components of an internal combustion engine starting circuit; 
         FIG. 2  is a schematic diagram showing an engine starting motor anti-milling device according to an embodiment of the present invention connected to other components of an internal combustion engine starting circuit; and 
         FIG. 3  is a schematic diagram showing an engine starting motor anti-milling device according to an embodiment of the present invention connected to other components of an internal combustion engine starting circuit. 
         FIG. 4  is a schematic diagram showing an engine starting motor anti-milling device according to an embodiment of the present invention connected to other components of an internal combustion engine starting circuit. 
     
    
    
     DESCRIPTION 
       FIG. 1  shows a schematic diagram of an internal combustion engine starting system  10  according to an embodiment of the present invention. Starting system  10  of  FIG. 1  comprises starter motor  14 , alternator  16 , battery  18 , power module  20 , solenoid  32 , and switch  40 . 
     Starter motor  14  is an internal combustion engine starter motor comprising a pinion gear (not shown). Starter motor  14  is installed in a typical arrangement with an internal combustion engine (not shown), where the pinion gear of starter motor  14  drives a flywheel ring gear (not shown) on the internal combustion engine in order to crank the internal combustion engine. Solenoid  32  is an internal combustion engine starter motor solenoid comprising pull-in coil  31 , hold-in coil  33 , and contacts  34 . 
     Alternator  16  is an internal combustion engine alternator. After the internal combustion engine has started, the alternator  16  is mechanically driven by the internal combustion engine and provides electric current to recharge battery  18 , and to fulfill the electrical needs of the vehicle or apparatus in which the internal combustion engine is installed. 
     Battery  18  is a battery, such as an automotive battery, comprising negative terminal  17  and positive terminal  19 . Battery  18  is connected to alternator  16  such that battery  18  can be charged by the electrical current delivered from alternator  16 . Switch  40  is an ignition switch of a type known in the art. 
     Power module  20  comprises M(+) terminal  22 , B(+) terminal  24 , Neg(−) terminal  26 , C terminal  28 , capacitor  30 , relay  42 , relay  44 , control logic device  46 , and, optionally, diode  52 . Relay  42  is an electrical relay comprising terminals  41 ,  43 , and  45 . Relay  42  is shown in  FIG. 1  as an electromechanical relay, however it is within the scope of the present invention to deploy a solid state relay as relay  42 . Relay  44  is an electrical relay comprising terminals  47 ,  49 , and  51 . Relay  44  is shown in  FIG. 1  as a solid state relay, however it is within the scope of the present invention to deploy an electromechanical relay as relay  44 . Terminal  45  of relay  42  is electrically connected to terminal  49  of relay  44 . 
     In an embodiment, capacitor  30  is an electric double layer capacitor of the type referred to as a “super capacitor” or an “ultra capacitor.” In an alternative embodiment, capacitor  30  may comprise a bank of capacitors. As shown  FIG. 1 , the positive lead of capacitor  30  is connected to terminal  43  of relay  42 . The negative lead of capacitor  30  is connected to Neg(−) terminal  26  and to terminal  47  of relay  44 . 
     Control logic device  46  is electrically connected to C terminal  28  and to terminal  51  of relay  44 . The function of control logic device  46  according to the present invention is discussed hereinafter. The function of control logic device  46  may be deployed in a number of different physical forms as may occur to one of skill in the art. For example, control logic device  46  may be comprised of electronic logic devices or may comprise a microprocessor and associated software. 
     B(+) terminal  24  is electrically connected to the positive terminal  19  of the battery  18 . C terminal  28  is electrically connected to node  50 , which is in the electrical path between the starter switch  40  and the solenoid  32 . The M(+) terminal  22  is electrically connected to B(+) terminal  24 , to terminal  41  of relay  42 , and to contacts  34 . Diode  52  may be included between the M(+) terminal  22  and B(+) terminal  24  to prevent discharging of capacitor  30  into battery  18 . When relay  42  is closed, M(+) terminal  22  is electrically connected to capacitor  30 . When contacts  34  are closed, M(+) terminal  22  is electrically connected to starter motor  14 . Neg(−) terminal  26  is electrically connected to ground. 
     In an embodiment, power module  20  comprises an insulated casing with capacitor  30 , relay  42 , relay  44 , and control logic  46  contained inside the insulated casing, and M(+) terminal  22 , B(+) terminal  24 , Neg(−) terminal  26 , and C terminal  28  protruding through the insulated case to electrically connect capacitor  30 , relay  42 , relay  44 , and control logic  46  to other components of the electrical system. 
     In the embodiment of starting system  10  shown in  FIG. 1 , battery  18  and capacitor  30  are available to provide cranking current to starter motor  14 . When switch  40  is closed, current flows from battery  18  to pull-in coil  31  and hold-in coil  33  of solenoid  32 , causing the contacts  34  to close. Closing contacts  34  short-circuits pull-in coil  31 , and causes the pinion gear of starter motor  14  to engage the flywheel ring gear of the internal combustion engine. 
     When switch  40  is closed, the current flow/voltage change is detected by control logic device  46  at node  50 . Upon sensing of this current/voltage change, control logic device  46  implements a short delay (e.g., less than one second) before providing a control signal to relay  44 . When this control signal is applied to relay  44 , a path is established between the windings of relay  42  and ground. Current flows through the windings of relay  42 , closing the relay contacts and establishing an electrical connection between capacitor  30  and M(+) terminal  22 . This allows the current from capacitor  30  to be delivered to starter motor  14  through closed contacts  34 . Because of the delay implemented by control logic device  46 , the current from capacitor  30  is not delivered to starter motor  14  until the pinion gear of starter motor  14  has been given the opportunity to fully engage the flywheel ring gear of the internal combustion engine. 
     In an embodiment of the present invention, control logic device  46  is designed to close relay  44  two-tenths (0.2) of a second after switch  40  is closed, and to open relay  44  thirty (30) seconds later or twenty-five (25) seconds after sensing a condition of greater than 14 volts at node  50 . Other timing parameters may be selected according to the needs of a practitioner of the present invention, with each selected parameter falling within the scope of the present invention. 
     Because relay  44  is closed for a period of time after the internal combustion engine is started, capacitor  30  is allowed to be recharged by alternator  16 . Once capacitor  30  is recharged, it must be prevented from discharging back into the battery. Thus, relay  44  is opened after a pre-determined period of time, or upon the sensing of certain conditions. In an embodiment, control logic device  46  also is designed to open relay  44  if a voltage of less than six volts is sensed at node  50 . 
       FIG. 2  shows a schematic diagram of another embodiment of internal combustion engine starting system  10  according to the present invention. The embodiment of starting system  10  of  FIG. 2  comprises many of the same elements shown in  FIG. 1 . However, in the embodiment of starting system  10  of  FIG. 2 , relay  42  and relay  44  are replaced by a single relay  54 . In the embodiment shown in  FIG. 2 , relay  54  is a solid state relay comprising terminals  56 ,  58 , and  59 , however it is within the scope of the present invention to use an electromechanical relay as relay  54 . Terminal  56  of relay  54  is electrically connected to the positive lead of capacitor  30 . Terminal  58  of relay  54  is electrically connected to M(+) terminal  22 . Terminal  59  of relay  54  is electrically connected to control logic device  46 . 
     In the embodiment of starting system  10  shown in  FIG. 2 , when switch  40  is closed, the current flow/voltage change is detected by control logic device  46  at node  50 . Upon sensing of this current/voltage change, control logic device  46  implements a short delay (e.g., less than one second) before providing a control signal to relay  54 . When this control signal is applied to relay  54 , relay  54  establishes an electrical connection between capacitor  30  and M(+) terminal  22 . This allows the current from capacitor  30  to be delivered to starter motor  14  through closed contacts  34 . Because of the delay implemented by control logic device  46 , the current from capacitor  30  is not delivered to starter motor  14  until the pinion gear of starter motor  14  has been given the opportunity to fully engage the flywheel ring gear of the internal combustion engine. 
     In an embodiment of the present invention, control logic device  46  is designed to close relay  54  two-tenths (0.2) of a second after switch  40  is closed, and to open relay  54  thirty (30) seconds later or twenty-five (25) seconds after sensing a condition of greater than 14 volts at node  50 . Other timing parameters may be selected according to the needs of a practitioner of the present invention, with each selected parameter falling within the scope of the present invention. 
     Because relay  54  is closed for a period or time after the internal combustion engine is started, capacitor  30  is allowed to be recharged by alternator  16 . Once the capacitor is recharged, it must be prevented from discharging back into the battery. Thus, relay  54  is opened after a pre-determined period of time, or upon the sensing of certain conditions. In an embodiment, control logic device  46  also is designed to open relay  54  if a voltage of less than six volts is sensed at node  50 . 
     As described above, power module  20  not only provides an additional power source for cranking an internal combustion engine, but also implements a delay between the time the ignition switch is closed and the time when the additional power source is called upon to provide cranking power for the internal combustion engine. In particular, power module  20  allows only one power source (e.g., a standard battery) to be used when the pinion gear is moved into engagement with the flywheel ring gear, thereby limiting the rotational speed and force of the pinion gear as it moves into engagement with the flywheel ring gear. This reduces the chance for less than full engagement between the pinion gear and flywheel ring gear as they are moved together, and reduces the chance for milling between the pinion gear and ring gear once the drive shaft of the starter motor transmits torque to the pinion gear. 
       FIG. 3  shows a schematic diagram of a internal combustion engine starting system  10  according to another embodiment of the present invention. Starting system  10  of  FIG. 3  comprises starter motor  14 , alternator  16 , battery  18 , capacitor  30 , solenoid  32 , switch  40 , optional diode  52 , and current limiting device  60 . Starter motor  14 , alternator  16 , battery  18 , capacitor  30 , solenoid  32 , switch  40 , and optional diode  52  are described above in reference to  FIGS. 1 and 2 . Current limiting device  60  comprises a pulse width modulation circuit designed to interrupt direct current at predetermined intervals, thereby producing pulses of direct current. In an embodiment, current limiting device  60  comprises a DC chopper device. 
     In the embodiment of starting system  10  shown in  FIG. 3 , when switch  40  is closed, current flows from battery  18  to pull-in coil  31  and hold-in coil  33  of solenoid  32 , causing contacts  34  to close. Closing contacts  34  short-circuits pull-in coil  31 , and causes the pinion gear (not shown) of starter motor  14  to engage the flywheel ring gear of the motor vehicle engine. The current flow/voltage change through switch  40  is detected by current limiting device  60  at node  50 . Upon sensing of this current/voltage change, current limiting device  60  operates to interrupt direct current from battery  18  and capacitor  30  at predetermined intervals. Pulses of direct current are thereby delivered to motor  14 . After a predetermined period of time, current limiting device  60  ceases its direct current pulsing effect, and uninterrupted direct current from battery  18  and capacitor  30  then is delivered to motor  14 . The effect of the temporary direct current pulsing created by current limiting device  60  is to reduce the rotational acceleration of starter motor  14 , thus enhancing the probability of proper engagement between the pinion gear and the flywheel ring gear before the full current from battery  18  and capacitor  30  is delivered to starter motor  14 . 
     In the embodiments shown in  FIGS. 1–3 , an electric double layer capacitor is deployed as an additional voltage source for providing internal combustion engine cranking current. However, any number of voltage sources can be used, such as one or more additional batteries. These additional voltage sources enhance battery  18  during engine cranking, and help maintain battery  18  at a higher state of charge, thereby extending the life of battery  18 . 
     In yet another embodiment, starting system  10  is adapted to include a sensor (not shown) that provides positional information about the pinion gear of motor  14 . In the embodiment of starting system  10  shown in  FIGS. 1 and 2 , such a sensor may be used in lieu of control logic device  46 . In operation, the sensor is operable to detect when the pinion gear of motor  14  has moved to a point where it necessarily must be engaged with the internal combustion engine ring gear. When this degree of movement is detected, the sensor is operable to actuate relay  44  (in the embodiment of  FIG. 1 ) or relay  54  (in the embodiment of  FIG. 2 ), thereby making the electrical connection between capacitor  30  and motor  14 . In the context of the embodiment shown in  FIG. 3 , when this degree of movement of the pinion gear is detected, the sensor is operable to cause current limiting device  60  to permit uninterrupted direct current from battery  18  and capacitor  30  to be delivered to motor  14 . 
       FIG. 4  shows a schematic diagram of a internal combustion engine starting system  10  according to another embodiment of the present invention. Starting system  10  of  FIG. 4  comprises starter motor  14 , alternator  16 , battery  18 , capacitor  30 , solenoid  32 , switch  40 , and current booster  70 . Starter motor  14 , alternator  16 , battery  18 , capacitor  30 , solenoid  32 , and switch  40  are described above in reference to  FIGS. 1 and 2 . Current booster  70  is operable to enhance the current delivered from battery  18  to starter motor  14 . In an embodiment, current booster  70  comprises a DC-to-DC converter circuit operable to boost the voltage of battery  18 , thereby delivering additional cranking current to starter motor  14 . 
     In the embodiment of starting system  10  shown in  FIG. 4 , when switch  40  is closed, current flows from battery  18  to pull-in coil  31  and hold-in coil  33  of solenoid  32 , causing contacts  34  to close. Closing contacts  34  short-circuits pull-in coil  31 , and current flows from battery  18  to starter motor  14  causing the pinion gear (not shown) of starter motor  14  to engage the flywheel ring gear of the motor vehicle engine. The current flow/voltage change through switch  40  is detected by current booster  70  at node  50 . Current booster  70  then is activated a predetermined period of time after the current flow/voltage change is detected at node  50 . When activated, current booster  70  boosts the voltage of battery  18 , thereby delivering additional cranking current to starter motor  14 . Because of the delay implemented by current booster  70 , the stepped up current is not delivered to starter motor  14  until the pinion gear of starter motor  14  has been given the opportunity to fully engage the flywheel ring gear of the internal combustion engine. 
     In an embodiment of the present invention, current booster  70  is activated two-tenths (0.2) of a second after switch  40  is closed, and deactivates thirty (30) seconds later or twenty-five (25) seconds after sensing a condition of greater than 14 volts at node  50 . Other timing parameters may be selected according to the needs of a practitioner of the present invention, with each selected parameter falling within the scope of the present invention. 
     While this invention has been described as having a preferred design, the present invention can be further modified within the scope and spirit of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Each such implementation falls within the scope of the present invention as disclosed herein and in the appended claims. Furthermore, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.