Abstract:
A method for jump starting a vehicle comprising causing a control unit to set a reference voltage by choosing a point from a chart plotting voltage across a starting battery versus time during a vehicle start; determining whether the voltage across a starting battery of the vehicle is less than the reference voltage; closing a switch if the determination is positive, thereby causing an external power source to supply high current to the starting battery; adding the high current and current from the starting battery to obtain a total current; and supplying the total current to a starter motor of the vehicle so as to start the vehicle. An apparatus for thus jump starting a vehicle is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method for jump starting a vehicle disabled by a depleted starting battery by connecting an external power source to the disabled vehicle&#39;s battery to quickly supply sufficient current to the vehicle&#39;s battery which in turn supplies required power to a starter motor for starting the disabled vehicle. 
     2. Description of Related Art 
     It is typical to jump start a vehicle disabled due to a dead battery. Jump starting is a method of starting a vehicle powered by an internal combustion engine when the vehicle&#39;s battery has been discharged. A second battery (often in another vehicle) is temporarily connected to provide starting power to the disabled vehicle. Once the disabled vehicle&#39;s engine is running, its alternator or generator, should recharge the discharged battery, so the second battery can be disconnected. 
     However, it can be quite difficult for a motorist to find another motorist to provide a jump start especially when the problem occurs at night or in a remote area. Calling an automobile repair shop is a solution. But its cost is high. Emergency road servicing may not be available. To provide an effective, reliable emergency assistance kit to enable a motorist to deal with a dead battery is therefore an object of the invention. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the invention to provide a method of jump starting a vehicle comprising the steps of causing a control unit to set a reference voltage by choosing a point from a chart plotting voltage versus time during a starting process; determining whether the voltage across a starting battery of the vehicle is less than the reference voltage or not; closing a switch if the determination is positive, thereby causing an external power source to supply additional current to the vehicle&#39;s discharged starting battery for a predetermined period of time; adding the sufficient current and current from the discharged starting battery to obtain a total current; and supplying the total current to a starter motor of the vehicle so as to start the disabled vehicle. 
     It is another object of the invention to provide an apparatus for jump starting a vehicle having a starter motor and a starting battery connected to the starter motor, the apparatus of the invention comprising in combination a control unit; an external power source connected in parallel to the starting battery by a switch controlled by the control unit; wherein the control unit sets a reference voltage by choosing a point Q from a chart plotting voltage across the starting battery versus time for a curve representing a starting process; wherein the control unit determines whether the voltage across the starting battery is less than the reference voltage; wherein the switch is closed when the voltage across the starting battery is less than the reference voltage as determined by the control unit; wherein the external power source supplies a sufficient current to the starting battery, such that the current from the external power source and the current from the starting battery are added to obtain a total current; and wherein the total current is supplied to the starter motor so as to start the vehicle. 
     The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flow chart illustrating a method for jump starting a vehicle according to the invention; 
         FIG. 2  schematically depicts an apparatus for jump starting a vehicle according to a first preferred embodiment of the invention; 
         FIG. 2A  schematically depicts an apparatus for jump starting a vehicle according to a second preferred embodiment of the invention; 
         FIG. 2B  schematically depicts an apparatus for jump starting a vehicle according to a third preferred embodiment of the invention; 
         FIG. 2C  schematically depicts an apparatus for jump starting a vehicle according to a fourth preferred embodiment of the invention; 
         FIG. 3  schematically depicts an apparatus for jump starting a vehicle according to a fifth preferred embodiment of the invention; 
         FIG. 4  schematically depicts an apparatus for jump starting a vehicle according to a sixth preferred embodiment of the invention; and 
         FIG. 5  is a chart plotting voltage across a starting battery versus time during a vehicle start. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As mentioned,  FIG. 5  is a chart plotting voltage across a starting battery versus time during a vehicle starting operation. A similar curve is observed in both normal and jump starts, i.e., the sharp drop-off in battery voltage between points P 2 , the voltage across the battery prior to initiation of the starting operation, and P 3 , the minimum voltage measured during the starting operation, is due to the large initial current drawn by operation of the starter motor. Operation of the starter motor during cranking of the engine, is represented by section P 4  of the curve, and P 5  shows the voltage increase after the engine starts, when the alternator or generator provides recharging current to the battery. According to the invention, a reference voltage point Q is chosen from a point beginning at point P 2  and ending at point P 5  by referring to the specifications of an automobile starting battery, manufacturer, and type. More specifically, point Q is chosen such that if the starting battery&#39;s voltage is at least equal to Q, the battery will likely be able to start the vehicle; if not, a jump start or other assistance will likely be required. According to one aspect of the present invention, a method of providing additional power to the starter motor is provided, so that the vehicle engine can be started. 
     Referring to  FIG. 1 , a flow chart illustrating a method of jump starting a vehicle in accordance with the invention, the method comprising the following steps: 
     Step 1: A reference voltage point Q is set by a control unit. 
     Step 2: It is determined whether the voltage across the starting battery of the vehicle is less than a reference voltage point Q or not. If the determination is yes, the flow chart goes to next step 3. Otherwise, the flow chart returns to step 1. 
     Step 3: A switch  35  (discussed further below) is closed (i.e., ON) automatically, connecting an external power source to the vehicle&#39;s discharged battery. 
     Step 4: The external power source supplies additional current I 2  to the vehicle&#39;s discharged battery. 
     Step 5: Current I 2  and current I 1  from the vehicle&#39;s discharged battery are added to obtain a total current I (i.e., I= 1   1 +I 2 ). 
     Step 6: The total current I is supplied to a starter motor of the vehicle so that the disabled vehicle can be started successfully. 
     Referring to  FIG. 2 , an apparatus for jump starting a vehicle according to a first preferred embodiment of the invention comprises the following components, as discussed in detail below. 
     A starting battery  10  is connected to a starter motor  20 , through a conventional switched connection  33 . A control unit  30  is connected to the starting battery  10  through an analog to digital converter (A/D)  37  so as to be able to measure the voltage across the battery  10 . Control unit  30  controls operation of a switch  35  so as to connect an external power source  50  in parallel with the starting battery  10 . An input and output device (e.g., audible and light device, a video display, or a voltage or current value display)  31  may be provided and is connected electrically to the control unit  30 , e.g., for display of the status of the external power source and associated components, 
     The control unit  30  can set a reference voltage Q and determine whether an output voltage of the starting battery  10  of a disabled vehicle is less than the reference voltage Q (e.g., a point between P 2  and P 5  in  FIG. 5 ) employing an analog to digital converter (A/D)  37  which uses sampling to convert a continuous quantity (i.e., the voltage across the starting battery  10 ) to a discrete time representation in digital form. That is, the control unit  30  can monitor the voltage across the starting battery  10  during a normal start, effectively generating the data shown in  FIG. 5 , and can then select the point Q between points P 2  and P 5 , more typically between P 2  and P 3 . A second A/D  34  can be provided to monitor the voltage of the external power source  50 . 
     Preferably, the control unit  30  is an electronic control unit, as detailed further below. 
     The external power source  50  is implemented as one or more cells of a mobile phone, a battery of a laptop computer, one or more cells of an iPad, one or more cells of an iPhone, or one or more cells of other types of portable electronic device. Experiment shows that the relatively small batteries of these devices can in fact provide sufficient additional current for a short time to serve as auxiliary power sources for jump starting vehicles. Alternatively, a dedicated external power source assembly (not shown) can be implemented as a plurality of series and/or parallel-connected cells. 
     The switch  35  is closed (ON) automatically by control unit  30 , connecting the external power source  50  to the starting battery  10 , when the output voltage of the starting battery  10  of the disabled vehicle is less than the reference voltage Q as determined by the control unit  30 . When the vehicle&#39;s starting circuit  33  is then activated, the external power source  50  supplies high current I 2  to the vehicle&#39;s discharged starting battery  10 . Current I 2  and current I 1  from the vehicle&#39;s discharged starting battery  10  are added to obtain a total current I (i.e., I=I 1 +I 2 ). The total current I is supplied to the starter motor  20  of the vehicle so that the disabled vehicle can be started successfully. 
     Preferably, the external power source  50  can supply high current I 2  (e.g., 0.1A to 550A) of low voltage (e.g., 0.5V to 12V). More preferably, the high current I 2  is 1A to 50A. The typical period of application of this current is between 0.001 second and 30 seconds; more preferably, between 0.001 second and 5 seconds. 
     In one embodiment, the control unit, switch  35 , and A/Ds  34  and  37  could be provided as a unit adapted to be connected between the vehicle&#39;s electrical system (e.g., by plug-in connection to an auxiliary jack) and a portable electronic device such as a mobile phone. In this way power from the battery of the mobile phone could conveniently be added to that of the vehicle starting battery as needed to start a disabled vehicle. The control unit  30  could also be provided with a pair of spring clamps, or the like, for direct connection to the terminals of the starting battery  10 . 
     Referring to  FIG. 2A , an apparatus for jump starting a vehicle in accordance with a second preferred embodiment of the invention is shown. The characteristics of the second preferred embodiment are substantially the same as that of the first preferred embodiment of  FIG. 2 , except the following: 
     A first capacitor  60  is provided in parallel to the external power source  50  for storing electrical energy supplied therefrom. The first capacitor  60  can store output current from the external power source  50  so as to supply high current I 2  of required voltage to the starter motor  20 . 
     As above, the switch  35  is closed (ON) automatically by control unit  30  when the output voltage of the starting battery  10  of the disabled vehicle is less than the reference voltage Q as determined by the control unit  30 . The external power source  50  and the first capacitor  60  then together supply high current I 2  to the vehicle&#39;s discharged starting battery  10 . Current I 2  and current I 1  from the vehicle&#39;s discharged starting battery  10  are added to obtain a total current I (i.e., I=I 1 +I 2 ). The high current I is supplied to the starter motor  20  of the vehicle when the primary starting circuit  33  is closed, so that the disabled vehicle can be started successfully. 
     Referring to  FIG. 2B , an apparatus for jump starting a vehicle in accordance with a third preferred embodiment of the invention is shown. The characteristics of the third preferred embodiment are substantially the same as that of the second preferred embodiment of  FIG. 2A , except the following: 
     A direct current to direct current (DC/DC) converter  40  is provided to interconnect the external power source  50  and the control unit  30 . DC/DC converter  40  is provided to raise the voltage from the battery of the external power source 50 (e.g., 6 volts) to a higher voltage (e.g., 12 volts) for supply to the starter motor  20 . A first capacitor  60  is provided in parallel to the DC/DC converter  40  for storing electrical energy supplied therefrom. The first capacitor  60  can store output current from the external power source  50  to high current I 2  of required voltage. 
     Again, the switch  35  is closed (ON) automatically by control unit  30  when the output voltage of the starting battery  10  of the disabled vehicle is less than the reference voltage Q as determined by the control unit  30 . The DC/DC converter  40  and the first capacitor  60  then together supply high current I 2  to the vehicle&#39;s discharged starting battery  10 . Current I 2  and current I 1  from the vehicle&#39;s discharged starting battery  10  are added to obtain a total current I (i.e., I=I 1 +I 2 ). The high current I is supplied to the starter motor  20  of the vehicle so that the disabled vehicle can be started successfully. 
     Referring to  FIG. 2C , an apparatus for jump starting a vehicle in accordance with a fourth preferred embodiment of the invention is shown. The characteristics of the fourth preferred embodiment are substantially the same as that of the second preferred embodiment of  FIG. 2A  except the following: 
     In addition to the first capacitor  60  provided in parallel to the external power source  50  for storing electrical energy supplied therefrom, a second capacitor  61  is provided in parallel to the starting battery  10  for storing electrical energy supplied therefrom. The first capacitor  60  can store output current from the external power source  50  to high current I 2  of required voltage and the second capacitor  61  can similarly store output current from the starting battery  10  to high current I 1  of required voltage. 
     Preferably, the capacitance of each of the first capacitor  60  and the second capacitor  61  is in the range of 0.01F to 1,000F depending on the capacity of the external power source  50 . 
     As above, the switch  35  is closed (ON) automatically by control unit  30  when the output voltage of the starting battery  10  of the disabled vehicle is less than the reference voltage Q, as determined by the control unit  30 . The external power source  50 , the first capacitor  60 , and the second capacitor  61  then together supply high current I 2  to the vehicle&#39;s discharged starting battery  10 . Current I 2  and current I 1  from the vehicle&#39;s discharged starting battery  10  are added to obtain a total current I (i.e., I=I 1 +I 2 ). The high current I is supplied to the starter motor  20  of the vehicle so that the disabled vehicle can be started successfully. 
     Referring to  FIG. 3 , an apparatus of jump starting a vehicle in accordance with a fifth preferred embodiment of the invention is shown. The characteristics of the fifth preferred embodiment are substantially the same as that of the third preferred embodiment of  FIG. 2B  except the following: 
     A voltage comparator  30 A is provided to replace the control unit  30  and the two A/Ds  34  and  37 . The voltage comparator  30 A compares the output voltage of the starting battery  10  of the disabled vehicle with the reference voltage Q. The switch  35  is closed (ON) automatically when the output voltage of the starting battery  10  of the disabled vehicle is less than reference voltage Q as a result of the comparison made by the voltage comparator  30 A. As in the embodiment of  FIG. 2B , a DC/DC converter  40  is provided in series with the external power source  50  and a first capacitor  60  is provided in parallel to the DC/DC converter  40  for storing electrical energy supplied therefrom. The first capacitor  60  can store output current of the external power source  50  to provide high current I 2 . 
     Referring to  FIG. 4 , an apparatus for jump starting a vehicle in accordance with a sixth preferred embodiment of the invention is shown. The characteristics of the sixth preferred embodiment are substantially the same as that of the third preferred embodiment of  FIG. 2B  except the following: 
     The control unit  30  is replaced by a microcontroller unit (MCU)  30 B which is a single chip that contains a processor, RAM, ROM, clock and I/O control unit. The MCU  30 B can determine whether the input voltage from the starting battery  10  of the disabled vehicle is less than reference voltage point Q by cooperating with the two A/Ds  34  and  37 . The switch  35  is closed (ON) automatically when the input voltage from the starting battery  10  of the disabled vehicle is less than the reference voltage point Q as a result of the determination made by the MCU  30 B. As above, the current I 2  from the external power source  50  and the current I 1  from the vehicle&#39;s discharged starting battery  10  are added to obtain a total current I (i.e., I=I 1 +I 2 ). The high current I is supplied to the starter motor  20  of the vehicle so that the disabled vehicle can be started successfully. 
     As above,  FIG. 5  is a chart plotting voltage across the starting battery  10  versus time during a starting process of an operable vehicle according to the first, second, third, fourth, fifth or sixth preferred embodiment of the invention. A similar Figure is shown in U.S. Pat. No. 6,791,464. As indicated above, a reference voltage point Q to which the voltage across the starting battery  10  is compared is chosen from a point beginning at point P 2  and ending at point P 5  by referring to the specifications of an automobile starting battery, manufacturer, performance and type thereof. In general, the reference voltage point Q is selected such that the method of the invention will be implemented when the voltage across the starting battery  10  has fallen to a point where it is unlikely that the starting battery will be unable to start the engine. 
     While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.