Patent Publication Number: US-8111036-B2

Title: System for electrically connecting and disconnecting a vehicle generator from a vehicle storage unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority to U.S. provisional patent application Ser. No. 60/785,810 filed 27 Mar. 2006, which is hereby incorporated by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     REFERENCE TO SEQUENCE LISTING 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to energy recovery systems, and particularly to systems that recover a vehicle&#39;s excess kinetic energy and convert it into stored electrical energy. The present invention also relates to a vehicle energy recovery system which can be retrofitted to a variety of vehicles including, but not limited to, cars, buses, trucks, aircraft, boats, trains and trailers and does not require computer control or programming to operate. 
     BACKGROUND OF THE INVENTION 
     Ever since the automobile was invented people have been working to make it more efficient. Obtaining the maximum energy out of the fuel that propels a vehicle is an age old problem which has been tackled in a number of manners. Recently, people have been improving vehicles&#39; efficiencies by recovering the excess kinetic energy that is transformed into heat when a vehicle brakes or decelerates. Modern systems rely upon computer control to detect operating states of the vehicle, such as using the output from an engine control unit. Other systems are directed towards making hybrid vehicles—that is vehicles with both an electric motor and an on-board fueled electricity generator—more efficient by using the electric motor to recover and convert kinetic energy into stored electrical energy. 
     A major disadvantage of the modern systems is that they require modern automobiles. Computer controlled engines have been around for several years, but there are a great many automobiles being driven that do not have complex electronic controllers in them. These older automobiles are not able to take advantage of the fuel savings modern technology can offer. 
     Another drawback of many of the modern systems is that they are expensive and complex. Greater reliance upon computer control to operate a system increases the complexity of the system as well as the likelihood that something will malfunction. 
     BRIEF SUMMARY OF THE INVENTION 
     There is a need to provide an energy recovery system that is simple and can be installed in any vehicle. There is also a need for an inexpensive energy recovery system that can pay for itself through fuel savings in a short period of time. The present invention overcomes the inability of prior energy recovery systems by abandoning the reliance upon computer controlled operations. 
     Embodiments of the present invention meet the above needs, and others, by using simple switches to detect operating states of a vehicle and using the simple switches to electrically connect and disconnect a vehicle&#39;s existing electric generator to an electric storage unit. Embodiments of the present invention can be used to recover and convert kinetic energy into stored electrical energy on a range of vehicles including, without limitation, automobiles, trucks, trains, aircraft and trailers pulled by other vehicles. Embodiments of the inventive energy recovery system are formed from a few switches electrically connected between an electric generator and an electric storage unit to selectively connect and disconnect the electric generator and the electric storage unit depending upon certain velocity states of a vehicle. 
     The present invention has advantages over the prior art and makes a technical contribution by providing a simple energy recovery system for a vehicle that does not rely upon complex electronics and can be mounted in almost any vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example, and not by way of limitation in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which: 
         FIG. 1  is a schematic diagram of a first embodiment of the present invention. 
         FIG. 2  is a schematic diagram of a second embodiment of the present invention. 
         FIG. 3  is a schematic diagram of a third embodiment of the present invention. 
         FIG. 4  is a schematic diagram of a fourth embodiment of the present invention. 
         FIG. 5  is a schematic diagram of a fifth embodiment of the present invention. 
         FIG. 6  is a schematic diagram of a sixth embodiment of the present invention. 
         FIG. 7  is a schematic diagram of a seventh embodiment of the present invention showing multiple switches and supplying stored electrical energy outside the vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention addresses and solves problems related to providing a reliable, inexpensive energy recovery system for a vehicle. The present invention also addresses and solves problems related to providing an energy recovery system that does not require complex electronic control and can be placed into a variety of vehicles. 
     The present invention solves the above problems by providing a switch operated energy recovery system as discussed below. One of ordinary skill in the art will realize that the following discussion is illustrative and intended to describe preferred embodiments of the present invention and is not intended to limit the present invention to the embodiments discussed. The present invention has numerous applications where kinetic energy can be recovered and converted into stored electrical energy. The present invention may be scaled and adapted to many applications and is defined by the claims, which set forth the metes and bounds of the present invention. 
     Referring now to the drawings, and initially to  FIG. 1 , an improved energy recovery system is described. An electrical generator  10  is mechanically linked to a vehicle&#39;s engine as is well known in the art. In alternate embodiments, electrical generator  10  is linked to a vehicle&#39;s wheels—for example when the vehicle is a trailer and has no engine. Electrical generators  10  are commonly alternators, however other electrical generators such as DC motors for example, are within the scope of the present invention. 
     In most prior art vehicles, the electric generator  10  is constantly connected to a vehicle&#39;s battery which is connected to a vehicle&#39;s electric load  40 . The prior art vehicles thus constantly generate electricity using the engine which consumes the engine&#39;s fuel to provide electricity for the vehicle. 
     Referring again to  FIG. 1 , the present invention selectively connects and disconnects a vehicle&#39;s electric generator  10  to and from an electric storage unit  30  to reduce the amount of fuel that is consumed to provide electricity for the vehicle. The present invention thereby increases a vehicle&#39;s fuel efficiency and also reduces wear on the brake systems. 
     The electric generator  10 , which in many instances is an alternator, is electrically connected to a reference load  15 . Other generators  10  which are not alternators do not require the reference load  15  as they do not experience the burnout problems alternators have. The reference load  15  provides a constant 12 volt source for the electric generator  10  to prevent the electric generator  10  from burning out. If some electric generators  10 , such as an alternator, are operated without being connected to a 12 volt load the electric generator  10  cannot determine how much current to generate and ends up burning out. To prevent this, a reference load  15  is provided. The reference load  15  is sized according to the electric generator&#39;s  10  output and according to whether the reference load  15  will perform duties such as providing a current to start a vehicle. In the preferred embodiment, the reference load  15  is a 12 volt motorcycle battery. 
     The present invention takes advantage of the fact that electric generators  10 , namely alternators, detect when a load cannot accept any more current and enter an idle mode. This happens when a voltage regulator in the electric generator  10  detects a predetermined voltage and electrically disconnects the rotor which then shuts down the stator current flow. By utilizing a relatively small reference load  15 , the electric generator  10  constantly “sees” a 12 volt potential. This causes the electric generator  10  to essentially freewheel and not produce a significant electric current when the electric generator  10  is electrically disconnected from the electric storage unit  30 . When this happens, the electric generator  10  is not producing a noticeable electric load with its attendant mechanical resistance and therefore does not require a significant amount of energy from the engine—which increases the vehicle&#39;s fuel efficiency. 
     In the embodiment depicted in  FIG. 1 , first switch  20  is normally open and prevents the electric generator  10  from electrically connecting to the electric storage unit  30 . For example, when a vehicle starts the starter motor draws current from either the reference load  15  or from the electric storage unit  30  as is well known in the art. Second switch  25  is open at vehicle start as is first switch  20  so there is no electrical connection between the electric generator  10  and the electric storage unit  30 . 
     Electric storage unit  30  is preferably a battery, including, but not limited to lead acid, nickel cadmium, lithium ion, gel, absorbed glass mat, or other battery type. Other electric storage devices, such as capacitors or fuel cells, are within the scope of the present invention. 
     Second switch  25  remains open during normal driving conditions, but is closed when the vehicle decelerates. When second switch  25  closes it sends a signal to first switch  20  causing first switch  20  to close. Once first switch  20  closes an electrical connection between the electric generator  10  and the electric storage unit  30  is made. Because the electric generator  10  is connected to the vehicle&#39;s engine, which is in turn connected to the vehicle&#39;s drive train, and the vehicle is decelerating, the electric generator  10  is being run predominantly by excess kinetic energy transferred from the drive train through the engine—not by fuel supplied to the engine. This excess kinetic energy is used to operate the electric generator  10  to create electricity which is supplied to the electric storage unit  30  through the closed first switch  20 . Operating the electric generator  10  in this manner causes resistance due to creating electricity and causes the vehicle to further decelerate. In embodiments without an engine, such as a trailer, the present invention links to the wheels and acts as a brake while it is generating electricity from the excess kinetic energy. 
     When the vehicle stops decelerating second switch  25  opens and stops sending the signal to first switch  20  to close, thereby opening first switch  20 . This causes the electric generator  10  to become electrically disconnected from the electric storage unit  30  and thus the electric generator  10  returns to an idle mode where it requires very little energy. The vehicle&#39;s electric load  40 —including for example, lights, radios and other electric devices—is operated by the current supplied from electric storage unit  30  regardless of whether electric storage unit  30  is connected to or disconnected from the electric generator  10 . 
     During the deceleration period electric storage unit  30  received an electric charge. For example, the electric charge is approximately 14 volts produced by the electric generator  10  which is ideal for charging a 12 volt source. The charging voltage will vary depending upon the needs of electric storage unit  30  as is well known in the art. As described in relation to  FIG. 7 , the electric current from electric storage unit  30  can also be transferred through items such as a transformer to supply electric power outside the vehicle. 
     First switch  20  is preferably an electronically controlled relay. For example, an L-Series ACR with Coil Economizer electronic relay manufactured by Blue Seas Systems™ is a durable switch for reliably connecting and disconnecting the electric generator  10  and the electric storage unit  30 . Other types of switches can be used for first switch  20  as long as they disconnect and connect the electric generator  10  and the electric storage unit  30  in response to the presence or absence of an electric signal generated by another switch, such as second switch  25 . 
     Second switch  25  can be any of a number of switches which are activated due to a change in the vehicle&#39;s velocity state. For example, second switch  25  can be a simple electric switch connected to a vehicle&#39;s brake light wires. When current flows through the brake light wires it activates second switch  25  to close, which in turn activates first switch  20  to close. With both first switch  20  and second switch  25  closed the electric generator  10  is producing electricity, as described above, which acts as a brake to further decelerate the vehicle. 
     The driver can maintain deceleration due to electric drag created by the electric generator  10  by lightly pressing on the vehicle&#39;s brake pedal. This prevents the mechanical brakes from contacting the rotors or drums and transforms excess kinetic energy into stored electric energy. If the user desires to stop the vehicle faster, then the brake pedal is depressed more to engage the mechanical brakes. If the user desires to stop decelerating, or accelerate, the brake pedal is returned to its non-depressed position which cuts off the electric current to the brake lights. Second switch  25  then deactivates and opens which causes first switch  20  to deactivate and open as well. 
     Second switch  25  can also be an accelerometer, a vacuum switch connected to a vacuum source in the engine, a pressure switch connected to a pressure source in the engine, an inertia switch, a switch measuring the rotational velocity of the vehicle&#39;s wheels or any other of a number of switches capable of detecting when a vehicle is decelerating. Second switch  25  can also be operated based upon mechanical conditions of the vehicle, for example second switch  25  could be activated when a vehicle&#39;s clutch is at a resting position and deactivates when the vehicle&#39;s clutch is activated, that is moved from its rest position, or vice versa. 
     An example of a vacuum switch is one that operates by detecting an increase in the manifold vacuum in a normally aspirated (non turbo or supercharged) engine. Preferably, the vacuum switch is a non-bouncing switch with a noticed hysteresis of about 4 inches of mercury to allow for activation at, for example, 25 inches of mercury and deactivation at, for example, 21 inches of mercury, to prevent the constant cycling of the switch on and off during moderate variations in vacuum. The vacuum increase causes second switch  25  to activate and operate the inventive system as described above. When the engine has more fuel and air supplied to it the manifold vacuum decreases—which occurs during vehicle acceleration. For example, a 4 inch of mercury decrease in the vacuum would deactivate second switch  25  and disconnect the electric generator  10  from the electric storage unit  30  as described above. Instead of detecting vacuum changes, a pressure switch could be used and the inventive system would then open and close the switches  25  and  20  accordingly. 
     Referring now to  FIG. 2 , a second embodiment of the present invention is described. The embodiment of  FIG. 2  is substantially the same as that depicted in  FIG. 1 . A third switch  26  is included in parallel with the second switch  25  and can be any of a number of switches which activates upon a change in the vehicle&#39;s acceleration state, including, but not limited to, vacuum switches, pressure switches, accelerometers, inertia switches and rotational velocity measuring switches, as described above. By connecting the second switch  25  and the third switch  26  in parallel the inventive system can have better automatic operating characteristics. 
     An exemplary system has a brake light activated switch as second switch  25  and a vacuum switch as third switch  26 . When a vehicle descends a hill the driver may press the brake pedal which activates the inventive system as described above. However, the driver may not want to constantly maintain recharging electric storage unit  30  through brake manipulation—especially when the electric drag created by the electric generator  10  is sufficient to keep the vehicle at an appropriate speed while descending the hill. Without the third switch  26 , if the driver releases the brake pedal the inventive system would disconnect and stop generating electricity from the excess kinetic energy. But, with the third switch  26 —which could be a vacuum switch for example—when the driver releases the brake pedal and opens second switch  25  the third switch  26  remains activated and closed which keeps the first switch  20  activated and closed. Therefore, the vehicle can descend the hill and convert excess kinetic energy into stored electric energy without requiring the driver to depress the brake pedal slightly during the entire descent of the hill. 
     Referring now to  FIG. 3 , a third embodiment of the present invention is described. The embodiment of  FIG. 3  is substantially the same as that depicted in  FIG. 2 . A fourth switch  27  is included in parallel with the second switch  25  and the third switch  26  and can be any of a number of switches which activate upon a change in the vehicle&#39;s velocity state, including, but not limited to, vacuum switches, pressure switches, accelerometers, inertia switches and rotational velocity measuring switches, as described above. By connecting the second switch  25 , the third switch  26  and the fourth switch  27  in parallel the inventive system can have better automatic operating characteristics. 
     Additional switches measuring different acceleration conditions of the vehicle are within the scope of the present invention. There is no limit to the number of switches that can be employed. Additionally, switches are not limited to being placed in parallel, but can be serially connected depending upon the system performance desired. One such example is described in relation to  FIG. 5 . 
     Referring now to  FIG. 4 , a fourth embodiment of the present invention is described. In addition to the arrangement depicted in  FIG. 1 , a charge sensor  50  is electrically connected between the first switch  20  and the electric storage unit  30 . The charge sensor  50  monitors the charge level of the electric storage unit  30  and activates upon detecting that the charge level of the electric storage unit  30  is at or below a predetermined level. For example, if the electric storage unit  30  has a 12 volt potential, but is drained to the point where only 10.5 volts remains, the charge sensor  50  sends a signal to the first switch  20  to close. An electrical connection is thus made between the electric generator  10  and the electric storage unit  30  causing electric storage unit  30  to be recharged. This may happen while the vehicle is driving at a constant velocity, accelerating or decelerating as it is dependent upon the charge level in the electric storage unit  30 , not the vehicle&#39;s velocity state. The charge sensor  50  will then send a second signal to the first switch  20  to open the first switch  20  upon reaching a predetermined condition, such as the passage of a set amount of time or the charge level of the electric storage unit  30  reaching a predetermined level. 
     Referring now to  FIG. 5 , a fifth embodiment of the present invention is described. The embodiment depicted in  FIG. 5  is substantially the same as the embodiment depicted in  FIG. 2 , but with the addition of a gate switch  60  connected between the second and third switches  25 ,  26  and the first switch  20 . Including a gate switch  60  improves the operation of the inventive system by permitting more control over when the electric generator  10  is electrically connected or disconnected from the electric storage unit  30 . 
     Using the configuration of  FIG. 2  as an example, the second switch  25  is activated by the electric current flowing to a vehicle&#39;s brake lights and the third switch  26  is activated by a vacuum increase in the engine. Gate switch  60 , for example, is an accelerometer, position or inertia switch which activates when the vehicle is decelerating. Gate switch  60  could also be activated when a vehicle&#39;s clutch is at a resting position and deactivates when the vehicle&#39;s clutch is activated, that is moved from its rest position, or vice versa. 
     When the vehicle decelerates either, or both, second switch  25  and third switch  26  activate as described above. However, no signal is input into first switch  20  until the gate switch  60  activates. Thus, gate switch  60  can be used to refine the sensitivity of the inventive system—for example by setting a threshold level of detected deceleration before gate switch  60  activates. 
     Another advantage is when the vehicle is stopped, but running. Most drivers depress the brake pedal when a vehicle is stopped. Without the gate switch  60  the activation signal from the second switch  25  would cause the first switch  20  to activate and connect the electric generator  10  to the electric storage unit  30  while the vehicle idles. Since an engine&#39;s efficiency and horsepower are low at idle, and an engine&#39;s fuel burn percentage is also low at idle, this is an undesirable time to have the electric generator  10  connected to the electric storage unit  30 . Since the gate switch  60  would not detect any deceleration while the vehicle is stopped it will deactivate and prevent the signal from the second switch  25  from reaching the first switch  20 . Because gate switch  60  is deactivated while the vehicle is stopped, gate switch  60  also prevents any signal from the third switch  26  reaching the first switch  20 . Thus, the electric generator  10  is not electrically connected to the electric storage unit  30  while the vehicle is stopped and idling. 
     Referring now to  FIG. 6 , a sixth embodiment of the present invention is described. The embodiment depicted in  FIG. 6  is substantially the same as the embodiment depicted in  FIG. 5  with the addition of a passive electricity generator  70 . Passive electricity generator  70  is, for example, a solar panel, wind turbine, thermal diodes, or other item capable of generating electricity using environmental inputs. As is well known in the art, passive electricity generator  70  can have a blocking diode  72  connected between the passive electricity generator  70  and the electric storage unit  30  to prevent reverse current flow. Other items such as a PV charge controller can be utilized instead of or in conjunction with blocking diode  72  as is well known in the art. Passive electricity generator  70  supplements the recharging of electric storage unit  30  and is sized to keep the electric storage unit  30  at a nearly full charge when the vehicle is not running. This prevents degradation of electric storage unit  30 &#39;s performance and helps to extend its useful lifetime. 
     Referring now to  FIG. 7 , a seventh embodiment of the present invention is described. In  FIG. 7  a plurality of switches  25 ,  26 ,  27  and  28  are connected in parallel to detect different conditions which indicate whether the vehicle is decelerating or not. A gate switch  60  is connected in series with the plurality of switches  25 ,  26 ,  27  and  28 . In this embodiment, gate switch  60  is an optical sensor that detects the rotational velocity of the vehicle&#39;s wheels. Operation of gate switch  60  and the plurality of switches  25 ,  26 ,  27  and  28  is similar to operation of the embodiment described in relation to  FIG. 5 . 
     Charge sensor  50  is electrically connected between the first switch  20  and the electric storage unit  30  and operates as described in relation to  FIG. 4 . 
     An output device  80  is electrically connected to electric storage unit  30 . For example, output device  80  is an inverter which changes the DC current from electric storage unit  30  into AC current suitable for household use, sale to an electric grid or other uses. Other devices for extracting the electric energy stored in electric storage unit  30  are well known and within the scope of the present invention and include DC as well as AC devices. Addition of an output device  80  allows a vehicle to carry a large capacity electric storage unit  30  which can then be used to provide power to non-vehicle related applications. Such an arrangement is especially useful in a vehicle, such as a trailer, that consumes very little electric power. 
     While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the described embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.