Patent Application
20070278990
The invention will now be described with reference to the drawings, wherein like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a method of boosting a vehicle battery by supplying a current to the battery, detecting an engine crank event, and, upon detecting the engine crank event, dynamically adjusting (i.e., first substantially increasing, and then decreasing) the current in response to battery voltage.
The method may also include verifying a crank-ready condition in the battery by comparing one or more of battery voltage, battery current, and battery charge accumulation to respective crank thresholds. In certain embodiments, this verification step occurs only after a minimum charging time has elapsed, ensuring that the battery has at least a minimum level of charge before cranking. Similarly, the verification process may time out after a maximum charging time, after which the operator may conclude that the battery is not efficiently or economically boostable and should be replaced rather than recharged and boosted. Once the crank ready condition is detected, the operator may be so signaled.
By supplying a baseline current to the battery, the present invention rapidly brings a battery to a crank-ready state (or, alternatively, rapidly determines that the battery will not achieve a crank-ready state and should be replaced). Further, by dynamically adjusting current to the battery in response to battery voltage, the present invention substantially reduces the risk of damage to or destruction of the battery during the boosting and cranking process.
An embodiment of the present inventive apparatus is illustrated in
A power transformer 116 is provided to step down both the voltage and current to a level that enables the charger 100 to charge and/or test a battery. In some embodiments, the power source 110 supplies the charger 100 with 120V AC. The power transformer 116 reduces the 120V AC to approximately 20-25V AC, which is optimal for charging the battery. Two lines 118, 120 from the power transformer 116 are inputted into a rectifier 124, while a third line 122 is directly coupled to a negative battery clamp 238. The lines 118, 120 pulse alternately through a full-wave rectifier 124 at a 60 Hz cycle. The diodes of the rectifier 124 convert the positive AC voltage to DC power supply. The third line 122 provides a return path for the negative voltage of outputs 118, 120 to return to the transformer 116.
A silicon control rectifier (“SCR”) 126 or thyristor is included in some embodiments to regulate the output from the rectifier 124 to the battery. A pulsed positive sine waveform with peak voltages and current exits from the rectifier 124. The sine waveform results in varying voltages and current being outputted from the rectifier 124. The SCR 126 operates as a switch allowing certain voltages and/or currents to pass to the battery.
The operator can choose a voltage, a current, or both to charge the battery. This selection is called a set-point. The set-point is transmitted to a field programmable gate array (“FPGA”) 142, discussed below, which then determines at which point in the sine wave to allow voltage to pass through to the battery. This point in the sine wave is related to the set-point as chosen by the operator. The set-point, depending on the selection of the operator, is situated on the sine wave by starting from the end of the sine wave and working in a rearward direction. Once the set-point is located on the sine wave, the voltage underneath the sine wave is allowed to pass through. Therefore, the set-point voltage is a mean value of a range of voltages.
For example, if the operator decides to charge the battery at 12V, this set-point of 12V is entered into the charger 100. The set-point is transmitted to the FPGA 142, which then determines at which point in the sine wave to allow the voltage or current to pass through to the battery. The 12V set-point in this example permits voltages larger than and less than 12V to pass through to the battery. The mean of the voltages distributed to the battery will approximately equal twelve volts.
SCR 126 is normally switched off until it receives a signal from an I/O control (input/output) 134. The voltage or current exiting from the rectifier 124 is transmitted to an analog-to-digital converter (“ADC”) 136. The ADC 136 in turn transmits the voltage or current information to a linked computer programmable logic device (“CPLD”) 140, which is linked to the FPGA 142. The FPGA 142, simulating a processor, determines the operability of the SCR 126 by comparing the previously programmed set-point value with the output value of the rectifier 124. If the output value of the rectifier 124 is equal or greater than the set-point of the SCR 126, then the FPGA 142 instructs the input/output (“I/O”) control 134 to send a signal to the SCR 126 to allow the output voltage or current to pass to the battery. For example, if the operator desires a minimum current of 20 amps, the SCR 126 will allow a current equal to or exceeding 20 amps to pass to the battery.
A current sensor 128 is provided at the output of the SCR 126 to monitor or sense the current exiting from the rectifier 124 and the SCR 126. The current from the rectifier 124 is relayed to the ADC 136, which like the voltage is fed to the CPLD 140 and then onto the FPGA 142. The FPGA 142 verifies if the current from the rectifier 124 is equal to or exceeds the current set-point value. The output from the current sensor 128 is connected to the battery clamps 238, 240.
In some embodiments of the present invention, a conventional processor is replaced by a dynamic FPGA 142. The use of the FPGA 142 allows a designer to make changes to the charger 100 without having to replace the processor. Changes to a mounted conventional processor requires remounting and reconfiguration of the charger 100 design, which in turn requires more design hours. With the use of the FPGA 142, the designer is allowed to make changes and additional costs on the fly without remounting or tiresome reconfiguration of the initial design.
The FPGA 142 is configured and arranged to operate as a conventional processor. In some embodiments of the invention, the FPGA 142 controls and processes a number of different functions of the charger 100, such as the intelligent boost function described herein. These functions are downloaded and stored into a memory device 144. It can also be stored in a RAM device 146. Once stored in these memory devices 144, 146, the code is downloaded into the FPGA 142 and executed. Upon execution of the code, the FPGA 142 begins to operate various controls of the charger 100, such as the SCR 126 for current and voltage control. Additionally, data can be inputted into the FPGA 142 through the input device 148, such as a keypad. The FPGA 142 can transmit to and receive information from an output display 150, a serial port 154, such as a printer port, a second serial port 152, such as an infrared bar code reader, a module port 156 that can accept various communication modules, or any other device that can communicate with the FPGA.
Upon start-up or boot-up of the charger 100, an image of a soft-core microprocessor is loaded from the memory (i.e. flash 144, RAM 146, etc.) into the FPGA 142. Therefore, there is an image of the FPGA 142 resident in the memory. Additionally, upon start-up, the CPLD 140 takes control of the data and address bus and clocks the FPGA 142 image from memory into the FPGA 142. As stated previously, this allows for redesign of the processor and the board without the need for remounting a processor. All that is necessary for a design change is to upload a new FPGA image into the memory device. Additionally, any new tests or operating parameters required by the operator can be easily upload into the FPGA 142 and executed. The preferred embodiment uses flash memory 144 to accomplish this function.
The output display 150 can be an integrated display or a remote display that relays information, such as data gathered from the charging and testing of the battery, and menu information. Additionally, the display 150 can notify the operator of any problems that have been detected. The serial port 154 may be a standard RS-232serial port for connecting a device such as a printer. One of ordinary skill in the art will recognize that the RS-232can be replaced with an RS-432, an infrared serial port or a wireless radio frequency port, such as BLUETOOTH™, or any other similar device.
In some embodiments of the current invention, a bar code port 152 is provided. The bar code port 152 may serve to operably connect a bar code reader (not shown) to the FPGA 142 or a microprocessor. In some embodiments, the bar code port 152 may be a conventional component, such as an RS-232. The bar code reader may be, for example, a conventional optical bar code reader, such as a gun or a wand type reader.
Battery tester charger 200 includes an intelligent boost function, controlled by a current source management module and, in certain embodiments, a battery monitoring module, to assist in starting the engine of a disabled vehicle. The intelligent boost function will be described with reference to the flowchart of
Referring now to
Battery tester charger 200 then begins to supply battery 202 with a relatively constant pre-charge current in step 304. In certain embodiments of the invention, for example as illustrated in
In step 308, battery tester charger 200 monitors battery 202 for a crank-ready condition. Monitoring of battery voltage, battery current, and/or battery charge accumulation may be accomplished, for example, via a battery monitoring software module loaded into battery tester charger 200 (i.e., loaded into FPGA 142 from memory 144, 146). In some embodiments of the invention, a crank-ready condition exists when the battery voltage exceeds a crank voltage threshold, the battery current exceeds a crank current threshold, and the battery charge accumulation exceeds a crank charge accumulation threshold. One skilled in the art will recognize that any or all of these factors may be used, either singly or in combination, to verify a crank-ready condition in the battery 202. By way of example only, the crank voltage threshold may be about 10.5 volts, the crank current threshold may be about 10 amps, and the crank charge accumulation threshold may be about 800 coulombs. That is, in this example, a crank-ready condition will not exist until the battery voltage exceeds 10.5 volts, the battery current exceeds 10 amps, and the battery charge accumulation exceeds 800 coulombs. It should be understood, however, that other thresholds may be set without departing from the spirit and scope of the present invention.
In some embodiments of the invention, battery tester charger 200 will not proceed to monitoring step 308 until a minimum charging time, (that is, a minimum duration of pre-charging step 304, such as about 20 seconds) has elapsed. This waiting period helps to ensure at least a minimum level of charge accumulation in battery 202, such that the operator does not attempt to crank a completely discharged battery 202, which could have undesirable consequences, including, but not limited to, permanently damaging or destroying the battery 202. It should be understood that, since charge accumulation within battery 202 is a function of both the pre-charge current and the duration of the pre-charge step 304, an increase in one may be accompanied by a decrease in the other and vice versa. That is, a shorter minimum charging time coupled with a higher pre-charge current is regarded as within the scope of the present invention, as is a longer minimum charging time coupled with a lower pre-charge current.
Similarly, monitoring step 308 may time out after a maximum charging time, such as 120 seconds, as shown in step 310. If the crank-ready condition is not verified within the window of the maximum charging time, boosting will cease in step 312. The operator may then properly conclude that it would be more economical to replace the battery 202 than to continue to attempt to boost it. One skilled in the art will recognize that the maximum charging time may be adjusted upwards or downwards without departing from the spirit and scope of the present invention.
If the crank-ready condition is verified in step 310, the operator may be so notified in step 314. For example, the LED may begin to flash or a tone may sound to alert the operator to crank the engine. While awaiting the crank event, battery tester charger 200 continues to pre-charge battery 202. Since pre-charging occurs at a relatively low current that is unlikely to adversely affect the vehicle's electrical system, it is not imperative to immediately crank the engine upon receiving notification.
Once the crank-ready condition has been verified and the operator so notified, battery tester charger 200 monitors the voltage of the battery 202 in order to detect an engine crank event in step 316. As shown in
Once battery tester charger 200 detects the voltage drop corresponding to a crank event, it begins to dynamically adjust the current to the battery 202 in response to the battery voltage. Dynamic adjustment may be accomplished, for example, via a current source management software module loaded into battery tester charger 200 (i.e., loaded in FPGA 142 from memory 144, 146). The battery voltage at the time of the crank event is stored in step 318 for subsequent use in determining whether the engine has started or not. A signal may also be provided to the operator to indicate that boost cycle is (i.e., dynamic current adjustment) is occurring; in certain embodiments, this signal is a flashing LED.
Dynamic current adjustment occurs in at least two phases: a peaking phase in step 320 and a recovery phase in step 322. Initially, battery tester charger 200 rapidly increases the current from the pre-charge amperage 404 to boost amperage 408, which may be over about 200 amps, in step 320. The boost amperage 408 provided in step 320, though helpful in overcoming the inertia of the dip in voltage profile 400 caused by cranking the engine, is potentially high enough to adversely affect the vehicle's electrical system, for example by blowing fuses or tripping circuit breakers. Thus, once the battery voltage profile 400 begins to recover, as shown in
In some embodiments, dynamic current reduction step 322 is a multi-stage process including: supplying about 180 amps for about 130 milliseconds in step 322a, supplying about 130 amps for about 400 milliseconds in step 322b, supplying about 100 amps for about 800 milliseconds in step 322c, and supplying about 60 amps for about 3 seconds in step 322d. One skilled in the art will recognize, however, that the duration and amperage in any particular stage of dynamic current reduction step 322 may vary without departing from the spirit and scope of the present invention. Similarly, it is contemplated that additional or fewer stages may comprise dynamic current reduction step 322. In short, dynamic current reduction step 322 is constrained by the input power supply (i.e., the maximum capacity of the power line), circuit breaker, and SCR limits, and, as discussed above, is governed by the battery voltage 414.
Once the current has been reduced in step 322, battery tester charger 200 halts the flow of current to battery 202 in step 324. A waiting period, such as 2.5 seconds, then ensues to permit vehicle systems to stabilize. At the conclusion of the waiting period, in step 326, battery tester charger 200 detects whether the engine has started or not. The engine status is determined by comparing a measured battery voltage to a reference voltage, where the reference voltage is derived from the voltage stored in step 318 by subtracting about one volt therefrom. If the measured battery voltage exceeds the reference voltage, battery tester charger 200 concludes that the engine has started, and the boost process will stop in step 312. The operator may then be notified that the boost cycle has completed successfully, for example by turning off the LED indicator or sounding a tone.
If, however, the measured battery voltage does not exceed the reference voltage, battery tester charger 200 concludes that the engine has not started. In this case, the process repeats from step 306 (that is, battery tester charger 200 returns to the pre-charge process and once again awaits a crank-ready condition).
An error monitoring step 328, further illustrated in
For example, in some embodiments of the invention, the battery tester/charger 200 can determine whether the connections between the battery 202 and the clamps 238, 240 are acceptable in step 334. A connection test may be performed at either the positive 240 or the negative clamp 238 connection by applying the connection test to the positive components 230, 240 or negative components 232, 238 of the battery tester charger 200. The connection test may equally be applied to both components. The connection test may be performed by comparing the voltage in the battery cables 230, 232 upstream from the connection of the clamps 238, 240, and the voltage at the connection of the clamps 238, 240. Voltage loss due to cable resistances 208, 210 may be considered and subtracted from the difference in voltage at the clamps 238, 240 and the upstream position. Additional differences in voltage between the upstream position and the connections of the clamps 238, 240 may be caused by clamp connection resistances 206, 204.
A portion 237, 239 (
The battery connections may be tested to determine the resistances 206, 204 associated with the connection when the battery 202 is charged by a current source 110 or exposed to a heavy load 144. Whether the battery 202 is charging or in use, large current will flow through the cables 230, 232 and clamps 240, 238. A sensor 220, 222 in the battery charger tester 200 senses the voltage upstream from the clamps 240, 238 and the battery terminals 234, 236 connections and inputs a signal representative of the voltage to opp amps 214, 212 or optionally to the ADC 136. For example, in some optional embodiments of the invention, the voltage may be sensed upstream from the current sense 128 in both cables 230, 232 as shown in
The resistance of the connections 206, 204 can be analyzed using Ohm's law, V=I·R, where V stands for voltage, I stands for current, and R stands for resistance. Simple algebraic manipulation yields R=V/I. The unknown connection resistances 206, 204 associated with the connection can be expressed in terms of known parameters of current and voltage, thus the resistances 206, 204 can be determined.
Once the connection resistances 206, 204 are determined, each connection can be evaluated to determine whether the connection is acceptable or not. In one embodiment, a method is provided and compares the connection resistances 206, 204 against a predetermined acceptable and non-acceptable range of connection resistance. Based on the comparison, the operator can determine whether the connection is acceptable or not.
In an alternative embodiment, a method is provided to compare the voltage differences between the isolated portions 237, 239 and the voltage in the cables 230, 232 at the upstream positions. If the difference in voltage between the two locations is negligible, then the connection is likely to be acceptable. Optionally, the difference in voltage due to cable resistances 208, 210 may be subtracted from the voltage difference or otherwise accounted for in determining whether the connections are acceptable or not. If the voltage difference is higher than a predetermined maximum amount, then the connection between the battery terminal 234 and the clamp 140 will likely be unacceptable.
If the connection is not acceptable, the battery tester charger 200 can alert or notify the operator in step 332, wherein the battery tester charger 200 also may stop the boost process. In some embodiments, the battery tester charger 200 may alert the operator as to which connection (positive or negative) is unacceptable or whether both are unacceptable. In some embodiments, the battery tester charger 200 may alert the operator that the connection(s) are acceptable. The operator may be alerted by a variety of ways, such as an indicator light, a message on a display screen, an audible signal, or other ways that are disclosed herein. Because the operator is warned that a connection is not acceptable, the operator may take corrective measures to improve the connection, such as cleaning or replacing the terminals 234, 236 or clamps 240, 238.
Referring to
Heavy load tests are highly accurate for testing charged batteries. If the battery to be tested is partially charged, then the test accurately determines whether the battery is defective. A person skilled in the art will recognize that any heavy load test procedure that is suitable for testing the condition of the battery may be used. Additionally, load as used herein can also be a charge.
Some embodiments of the present invention also include an infrared temperature sensor 164, which aids in monitoring both the charger 100 and the battery being charged. The infrared temperature sensor 164 ensures that both the battery and charger 100 are maintained at safe temperature levels. The infrared sensor 164 may be contained within a housing. The housing is placed over the charging battery for safety reasons especially in the instance that, while charging, the battery unexpectedly explodes. The housing aids in containing the surrounding areas from the contaminants of the exploded battery.
The infrared temperature sensor 164 is placed within the housing to monitor the temperature of a charging battery. While charging a battery, heat is discharged or dissipated from the battery. However, excessive heat is an indication that the battery is being charged at an excessive rate. In some embodiments, the infrared temperature sensor 164 is linked to the ADC 136, essentially an input to the ADC 136, which relays the information to the CPLD 140, which then relays it to the FPGA 142. The FPGA 142, with the help of the infrared temperature sensor 164, can monitor the temperature of the battery and relay the information, including any problems, to the operator. The infrared temperature sensor 164 is aimed at the battery to ensure that the temperature of the battery is being monitored throughout the charging process. For example, if the battery being charged contains a short, the battery will heat excessively in a short period of time. The feedback from the infrared temperature sensor 164 can be used to alert the operator of the problem so that the operator can take the appropriate action.
In other embodiments, the infrared temperature sensor 164 can be aimed at the charger 100 only or in combination with the battery. By monitoring the charger 100, any excessive temperature generated by the charger can be relayed to the operator, thus appropriate actions can be taken to avoid overheating and damaging the charger. One of ordinary skill in the art will further recognize that the temperature sensor 164 can be located in a number of different locations in the charger 100 or linked to the charger 100. The location of the infrared temperature sensor 164 is not limited to a housing. Additionally, temperature sensors are needed most when the battery is charging. Therefore, monitoring the temperature of the battery and/or the charger can help to prevent battery explosions.
As further illustrated in
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
