The present invention relates to the field of motor vehicles, and particularly to electrical power systems for motor vehicles.
During normal operation of a motor vehicle, the battery is used to provide electric current to crank the engine during starting. Once the engine starts and begins running at increased speeds, the vehicle alternator re-charges the battery so the battery will have plenty of charge for the next start. However, in situations where the engine starts and stop many times over a short period of time, drained batteries are often encountered because the alternator does not have sufficient opportunity to re-charge the battery. Drained batteries not only result in the need for jump starts, but also tend to shorten battery life.
Delivery vehicles are particularly susceptible to drained batteries since the nature of activities associated with delivery vehicles involves repeated stopping and re-starting the vehicle as numerous deliveries are made with only short distances between each stop. As discussed above, the repeated starting and stopping of the delivery vehicle engine subjects the vehicle battery to an unusually high number of discharge cycles. Because the driving time between stops is typically short, there is little time to re-charge the battery during those driving times. Near the end of the day, once a delivery vehicle has made numerous starts and stops, the battery in the vehicle is often drained and cannot provide the current required to crank the engine. The result is that the operator of the delivery vehicle must have the vehicle jump-started or towed to a maintenance facility. Accordingly, it would be advantageous to provide a system that supplements a traditional battery in an automotive vehicle (delivery vehicle or otherwise) so the vehicle battery does not have to provide all the energy for starting the engine.
In an embodiment, the present invention comprises an electrically conductive isolation device, the electrically conductive isolation device comprising a first connection point and a second connection point, wherein flow of electric current from the first connection point to the second connection point is permitted, and flow of electric current from the second connection point to the first connection point is resisted; means for storing an electric charge, the means for storing an electric charge comprising a positive lead and a negative lead, the means for storing an electric charge having a capacitance of less than 321 farads, the positive lead electrically connected to the second connection point of the electrically conductive isolation device; means for electrically connecting the positive lead to an external electric load; means for electrically connecting the negative lead to ground; and means for electrically connecting the first connection point of the electrically conductive isolation device to a positive terminal of an external DC voltage source.
In an embodiment, the present invention comprises a starter motor; a generator; a battery, the battery having a positive terminal and a negative terminal, the positive terminal electrically connected to the generator; an electrically conductive isolation device, the electrically conductive isolation device comprising a first connection point and a second connection point, wherein flow of electric current from the first connection point to the second connection point is permitted, and flow of electric current from the second connection point to the first connection point is resisted, the first connection point of the electrically conductive isolation device electrically connected to the positive terminal of the battery, the first connection point of the electrically conductive isolation device electrically connected to the generator; means for storing an electric charge, the means for storing an electric charge comprising a positive lead and a negative lead, the means for storing an electric charge having a capacitance of less than 321 farads, the positive lead electrically connected to the second connection point of the electrically conductive isolation device, the negative lead electrically connected to ground; and means for electrically connecting the positive lead to the starter motor.
In an embodiment, the present invention comprises means for storing an electric charge, the means for storing an electric charge comprising a positive lead and a negative lead, the negative lead electrically connected to ground; and a rechargeable DC voltage source comprising a positive terminal and a negative terminal, the negative terminal electrically connected to the negative lead, the rechargeable DC voltage source connected in parallel with the means for storing an electric charge, wherein the means for storing an electric charge and the rechargeable DC voltage source are contained in unitary package.
In an embodiment, the present invention comprises means for storing an electric charge, the means for storing an electric charge comprising a positive lead and a negative lead, the negative lead electrically connected to ground; a rechargeable DC voltage source comprising a positive terminal and a negative terminal, the negative terminal electrically connected to the negative lead; and an electrically conductive isolation device, the electrically conductive isolation device comprising a first connection point and a second connection point, wherein flow of electric current from the first connection point to the second connection point is permitted, and flow of electric current from the second connection point to the first connection point is resisted, the first connection point electrically connected to the positive terminal, the second connection point electrically connected to the positive lead, wherein the means for storing an electric charge, the electrically conductive isolation device, and the rechargeable DC voltage source are contained in unitary package.
In an embodiment, the present invention comprises a starter motor; a generator; and a unitary power module, the unitary power module comprising (i) an electrically conductive isolation device, the electrically conductive isolation device comprising a first connection point and a second connection point, wherein flow of electric current from the first connection point to the second connection point is permitted, and flow of electric current from the second connection point to the first connection point is resisted, the first connection point of the electrically conductive isolation device electrically connected to the generator, (ii) means for storing an electric charge, the means for storing an electric charge comprising a positive lead and a negative lead, the positive lead electrically connected to the second connection point of the electrically conductive isolation device, the negative lead electrically connected to ground, and (iii) a first battery, the first battery comprising a first positive terminal and a first negative terminal, the first negative terminal electrically connected to the negative lead, the first positive terminal electrically connected to the first connection point of the electrically conductive isolation device.
In aspects of the foregoing embodiments of the present invention, the electrically conductive isolation device comprises a diode. In aspects of the foregoing embodiments of the present invention, the electrically conductive isolation device comprises an arrangement of electrically interconnected active components. In aspects of the foregoing embodiments of the present invention, the means for storing an electric charge comprises at least one electric double layer capacitor. In aspects of the foregoing embodiments of the present invention further comprises a voltage booster connected in parallel with the electrically conductive isolation device.
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:
As shown in
An arrangement of electrical components within an embodiment of the power module 20 is shown in
An isolation circuit (represented by dotted lines 32) is also positioned within the housing that contains power module 20. The isolation circuit 32 comprises a diode 34 connected in series with a fuse 36. Fuse 36 is optional in this arrangement. The isolation circuit connects the B(+) terminal 24 to the M(+) terminal 22 within the housing of the module 20. The positioning of the diode 34 in the isolation circuit allows current to flow from the B(+) terminal 24 to the M(+) terminal 22, but prevents current flow in the opposite direction. This isolates the capacitor 30 from the vehicle battery 18, and prevents the capacitor 30 from discharging into the vehicle battery 18.
An alternative arrangement for the electrical components in the module 20 is shown in
Another alternative arrangement for the electrical components in the module 20 is shown in
Another alternative arrangement for the electrical components in the module 20 is shown in
Another alternative arrangement for the electrical components in the module 20 is shown in
Another alternative arrangement for the electrical components in the module 20 is shown in
Another alternative arrangement for the electrical components in the module 20 is shown in
In operation, the module is first connected to a vehicle's electrical system, as described above with reference to
Once the engine starts following cranking, a substantial amount of energy has been drained from the capacitor, and the capacitor is ready for recharge. However, when the engine first starts, and is running at idle speed, there is typically not enough current generated from the charging system (i.e., alternator/generator) to completely re-charge the capacitor. If the vehicle's standard vehicle battery 18 and/or the power module battery 42 of the module are sufficiently charged, they may provide some immediate current for re-charging the capacitor. Alternatively, once the engine is operated at an increased speed above idle speed, the generator will provide current for recharging the battery (or batteries) and the capacitor. Because the capacitor 30 is an energy storing device that is capable of fast charge and discharge cycles, operation of the engine for only a short amount of time at speeds above idle speed (e.g., 20 seconds) will fully re-charge the capacitor 30.
During charging of the capacitor 30, energy flows through the fuse 36 and a diode 34 acting as the isolation circuit. During and after re-charging of the capacitor 30, the diode 34 of the isolation circuit 32 provides one-way flow of energy from the charging system to the capacitor 30 in the module. By providing isolation from the charging system, the module's energy cannot be drained back to the vehicle battery 18 while the vehicle is idling at a stop or if the engine is not running and there is an electrical load on the vehicle (flashers, radio, lighting, etc.). The fuse 36 protects the diode 34 and also serves as a safety device to disconnect the vehicle battery 18 from the starter 14 in the event of stuck contacts on the starting motor solenoid.
In an alternative embodiment shown in
As described above, the power module according to the present invention features short re-charge times which are particularly valuable in the delivery vehicle market. Because of low internal resistance, the capacitor banks are also capable of providing cranking current at a lower voltage than the battery. In addition, the module is continuously connected to the charging system of the vehicle, which makes implementation of the module in a vehicle relatively simple with no switching. The module may also take advantage of the presence of the secondary battery during starting, thereby allowing the module to be designed with smaller banks of capacitors. The module with a secondary battery is sized such that it can be used in place of a vehicle's standard battery, or it can be used to supplement the vehicle's standard battery. Furthermore, the existence of the module provides for longer battery life, as less reliance on the battery helps avoid extremely deep battery discharge.
Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other versions are possible. For example, to protect the generator from the requirement of immediately operating at full load upon engine fire the until the capacitor has re-charged, the charge current to the capacitor may be limited by electronic means or by simply introducing some resistance to the isolation circuit (e.g., simply adding a resistor or choosing a diode with a ‘slow response’). As another example, if milling issues are noticed between the starter motor and flywheel due to the higher energy available from the use of capacitors as an energy storage device, resistance may be added to the lead/cable connecting the starter motor to the module (e.g., by making the leads longer, thus increasing the resistance in the connection and reducing the initial current the starting motor solenoid receives). Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/484,719, filed Jul. 3, 2003, the disclosure of which is incorporated by reference.
Number | Date | Country | |
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60484719 | Jul 2003 | US |