Fuel injector heater element control via single data line
View Patent ↗A system, heated fuel injector, and controller for closed-loop temperature control of a heated fuel injector having simultaneous two-way data communication over a single-line data connection. The system includes a voltage source to output a heater enable signal and a variable current sink configured to draw a current value indicative of a temperature value related to the heated fuel injector. The heater signal and the current value are simultaneously present on the single-line data connection. The configuration reduces the effect of ground shift on the accuracy of determining a feedback signal from the heated fuel injector. The feedback signal is a temperature value related to the heated fuel injector and is indicated by a current value. Because the feedback signal is a current value, the feedback signal is generally immune from being influenced by ground shift between the controller and the heated fuel injector.
1. A system for closed-loop temperature control of a heater element thermally coupled to a heated fuel injector, said system having two-way data communication via a single-line data connection, said system comprising:
a voltage source configured to output a heater enable signal on the single-line data connection, wherein said heater enable signal has a voltage value indicative of a heater enable state; and
a variable current sink configured to draw a current value from the single-line data connection, wherein said current value is indicative of a temperature value related to the heated fuel injector,
wherein the indications of the heater enable state and the temperature value are simultaneously present on the single-line data connection.
2. The system in accordance with claim 1 , wherein said voltage source is a weak voltage source such that the voltage value is influenced by the current value.
3. The system in accordance with claim 2 , wherein the weak voltage source comprises a series resistor.
4. The system in accordance with claim 1 , wherein said system further comprises a voltage detector configured to detect the voltage value.
5. The system in accordance with claim 1 , wherein said system further comprises a current detector configured to detect the current value.
6. The system in accordance with claim 1 , wherein said system further comprises a voltage detector configured to detect the voltage value; and a current detector configured to detect the current value.
7. The system in accordance with claim 1 , wherein said system further comprises a temperature limit control circuit configured to override the heater enable signal if the temperature value is greater than a temperature maximum.
8. The system in accordance with claim 7 , wherein said temperature limit control circuit is further configured to stop overriding the heater enable signal if the temperature value becomes less than a temperature minimum.
9. A heated fuel injector configured for closed-loop temperature control of a heater element thermally coupled to the heated fuel injector, said heated fuel injector having two-way data communication via a single-line data connection, said heated fuel injector comprising:
a voltage detector configured to detect a voltage value on the single-line data connection; and
a variable current sink configured to draw a current value from the single-line data connection, wherein said current value is indicative of a temperature value related to the heated fuel injector,
wherein the indications of the heater enable state and the temperature value are simultaneously present on the single-line data connection.
10. The heated fuel injector in accordance with claim 9 , wherein said heated fuel injector further comprises a temperature limit control circuit configured to override the heater enable signal if the temperature value is greater than a temperature maximum.
11. The heated fuel injector in accordance with claim 10 , wherein said temperature limit control circuit is further configured to stop overriding the heater enable signal if the temperature value becomes less than a temperature minimum.
12. A heated fuel injector controller for closed-loop temperature control of a heater element thermally coupled to a heated fuel injector, said heated fuel injector controller having two-way data communication via a single-line data connection, said heated fuel injector controller comprising:
a voltage source configured to output a heater enable signal on the single-line data connection, wherein said heater enable signal has a voltage value indicative of a heater enable state; and
a current detector configured to detect a current value on the single-line data connection, wherein said current value is indicative of a temperature value,
wherein the indications of the heater enable state and the temperature value are simultaneously present on the single-line data connection.
13. The system in accordance with claim 12 , wherein said voltage source is a weak voltage source such that the voltage value arising from the heater enable signal is dependent on a source current output by the weak voltage source.
14. The system in accordance with claim 13 , wherein said weak voltage source comprises a voltage source and a series resistor.