Autonomous Glow Driver For Radio Controlled Engines

• US 20160305394A1
• Filed: 04/14/2015
• Published: 10/20/2016
• Est. Priority Date: 04/14/2015
• Status: Active Grant

• Current Assignee: Sheldon J. Demmons
• Original Assignee: Sheldon J. Demmons
• Inventors: Demmons, Sheldon J.
• Granted Patent: US 9,657,707 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02B 75/34 Ultra-small engines, e.g. for driving models
• CPC Class Codes: F02N 11/0807 Remote means
• CPC Class Codes: F02N 19/04 by heating of fluids used in engines
• CPC Class Codes: F02N 2300/306 with external senders or receivers, e.g. receiving signals from traffic lights, other vehicles or base stations
• CPC Class Codes: F02P 19/023 Individual control of the glow plugs
• CPC Class Codes: F02P 19/025 with means for determining glow plug temperature or glow plug resistance
• CPC Class Codes: F02P 19/026 Glow plug actuation during engine operation

Abstract

An autonomous glow driver system for radio controlled (RC) engines. Aspects of the system include a connector that securely attaches to the glow plug to maintain good electrical contact with the glow plug and reduce signal noise and using a current and differential amplifiers to determine the temperature of the glow element and the RPMs of the glow engine from a voltage signal (obtained via the connector) that varies with the temperature as induced changes in the resistance of the glow element occur. Using the data of temperature, non-running RPM, and running RPM to control operation of the glow driver leads to a very reliable approach to automatically activating the glow driver to maintain the combustion chamber temperature of the glow engine at a selected level because RPM is indicative of a rotating engine whereas temperature is not.

Claims

1. An autonomous glow driver system for use with an engine having a glow plug, the glow plug having a prong, a body, and a glow element, wherein the glow element has a resistance that changes in response to temperature variations, the autonomous glow driver system comprising:

a temperature signal processor in electrical communication with the glow element, the temperature signal processor monitoring a glow element voltage corresponding to the temperature at the glow element and producing a temperature signal;

an RPM signal processor in electrical communication with the glow element and the temperature signal processor, the RPM signal processor producing an RPM signal based on a comparison of an amplified glow element voltage corresponding to the glow element voltage and a varying reference voltage;

a glow driver in electrical communication with the glow element and selectively supplying an activation voltage to the glow plug via the glow element in response to a control signal; and

a controller in electrical communication with the glow driver, the controller receiving the temperature signal and the RPM signal and producing the control signal when the temperature signal reaches a threshold value corresponding to a selected temperature.

2. The autonomous glow driver system of claim 1 wherein the RPM signal comprises a series of pulses where the amplified glow element voltage has a magnitude exceeding the varying reference voltage.

3. The autonomous glow driver system of claim 1 wherein the RPM signal processor applies an AC gain to the glow element voltage to produce the amplified glow element voltage.

4. The autonomous glow driver system of claim 1 wherein the temperature signal processor applies a DC gain to the temperature signal to produce the varying reference voltage.

5. The autonomous glow driver system of claim 1 further comprising a current source in electrical communication with the glow element, the current source supplying a constant current passing through the glow element to establish a linear relationship between the resistance of the glow element and the glow element voltage.

6. The autonomous glow driver system of claim 5 wherein the amplified glow element voltage is biased back to the voltage at the output of the current source.

7. The autonomous glow driver system of claim 1 wherein the glow element maintains a secure physical and electrical connection with the glow plug to reduce electrical noise when measuring the glow element voltage.

8. The autonomous glow driver system of claim 1 wherein the varying reference voltage is equal to the glow element voltage plus a fixed offset voltage.

9. The autonomous glow driver system of claim 1 wherein the controller produces the control signal when the temperature signal reaches a threshold value and the RPM signal has pulses at a frequency corresponding to one of a non-running RPM and a running RPM.

10. The autonomous glow driver system of claim 1 wherein the controller includes a safety preventing the controller from producing the control signal when RPM signal has pulses occurring at a frequency below a minimum threshold RPM corresponding to an attempt to hand start the glow engine.

11. The autonomous glow driver system of claim 10 wherein the minimum threshold RPM is approximately 10 Hz.

12. The autonomous glow driver system of claim 10 further comprising a manual switch in communication with the controller, activation of the manual switch temporarily overriding the safety and allowing the controller to generate the control signal during an attempt to hand start the glow engine.

13. A method of operating a glow driver for a glow plug in a system comprising a connector secured to the glow plug, a temperature signal processor in electrical communication with the connector, an RPM signal processor in electrical communication with the connector and the temperature signal processor, the glow driver in electrical communication with the connector, and a controller in electrical communication with the glow driver, the method comprising the acts of:

monitoring a glow element voltage corresponding to the temperature at the glow element via an electrical connection to the glow plug;

producing a temperature voltage corresponding to the glow element voltage;

amplifying the temperature voltage to produce a varying reference voltage;

producing an RPM signal based on a comparison of an amplified glow element voltage corresponding to the glow element voltage and the varying reference voltage via the RPM signal processor;

automatically producing a control signal when the temperature voltage reaches an autoglow threshold value corresponding to a selected temperature; and

selectively activating the glow plug via the glow element in response to the control signal.

14. The method of claim 13 further comprising the act of setting the autoglow threshold value to the temperature voltage present while the glow engine is operating at a selected RPM level.

15. The method of claim 13 wherein the control signal is produced when the temperature voltage drops below the autoglow threshold value while the glow engine is operating.

16. The method of claim 13 further comprising the act of determining if the glow engine is operating at a running RPM level or a non-running RPM based on the RPM signal.

17. The method of claim 16 wherein the control signal is produced when the temperature voltage drops below the autoglow threshold value while the glow engine is operating at a running RPM level.

18. The method of claim 16 further comprising the act of automatically setting an autostart threshold value to a voltage corresponding to the glow element temperature present when the controller is initialized plus a selected temperature offset.

19. The method of claim 18 wherein the control signal is produced when the autoglow threshold value is not set and the temperature voltage drops below the autostart threshold value while the glow engine is operating at a running RPM.

20. The method of claim 18 wherein the control signal is produced when the temperature voltage is below the autostart threshold value and the glow engine is operating at a non-running RPM.