VEHICLE HEATERS AND CONTROLS THEREFOR

• US 20100170954A1
• Filed: 09/07/2009
• Published: 07/08/2010
• Est. Priority Date: 07/15/2002
• Status: Active Grant

• Current Assignee: TM Canada Acquisation Corp.
• Original Assignee: TM Canada Acquisation Corp.
• Inventors: Young, Jonathan, Paul, Douglas Thompson, Faccone, Angelo
• Granted Patent: US 9,428,036 B2
• Time in Patent Office: Days
• US Class Current: 237/12.30C
• CPC Class Codes: B60H 1/2206 controlling the operation of burners control of burners in general F23N5/00
• CPC Class Codes: B60H 1/2209 arrangements of burners for heating an intermediate liquid B60H1/032 takes precedence
• CPC Class Codes: F23N 2223/04 Memory
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 2227/10 Sequential burner running
• CPC Class Codes: F23N 2231/10 for component failures
• CPC Class Codes: F23N 2233/08 with variable speed
• CPC Class Codes: F23N 2241/14 Vehicle heating, the heat being derived otherwise than from the propulsion plant
• CPC Class Codes: F23N 3/082 using electronic means
• CPC Class Codes: F23N 5/203 using electronic means

Abstract

A heater for a liquid has a combustion chamber, a jacket for the liquid extending about the combustion chamber and a burner head assembly connected to the combustion chamber. The burner head assembly includes a housing having a burner mounted thereon and a hollow interior. A control module and a fan are mounted in the hollow interior, the fan being connected to an electric motor. A compressor and a fuel pump are mounted on the housing and are operatively connected to the electric motor. The control module may include controls for exercising components of the heater prior to combustion, thereby verifying operation of these components. Preferably there is a speed control for the motor, such as a closed loop speed control which regulates motor speed and accordingly output of the heater. Preferably there is a backup system using a lookup table in the event that the closed loop speed control fails. Also preferably there is provision for monitoring flame sensor functionality by providing an indicator light which mirrors operation of the flame sensor. The heater may have a selective soft start for the coolant pump which operates only when required so as to reduce unnecessary chatter on the motor relay. A system is also provided for distinguishing true overcurrent faults from overcurrents arising from voltage changes during starting of the vehicle engine. Reignition algorithms are provided to restart the burner in the event of flame sputters caused, for example, by fuel bubbles, but shut off the heater in the event that the fuel is truly cut off.

Claims

1. A heater for a liquid, the heater having a combustion chamber, a jacket for the liquid extending about the combustion chamber and a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior, a control module and a fan being mounted in the hollow interior, the fan being connected to an electric motor, a compressor and a fuel pump being mounted on the housing, the compressor and the fuel pump being operatively connected to the electric motor, the control module including a speed control for the motor which maintains the heater at a specified level of operation.

2. The heater as claimed in claim 1, wherein the speed control is a closed loop feedback control.

3. The heater as claimed in claim 1, wherein the speed control includes a sensor in the interior of the housing which is responsive to rotational speeds of the fan.

4. The heater as claimed in claim 3, wherein the fan includes a fan blade assembly rotated by the motor, a device being mounted on the fan blade assembly which triggers the sensor on each rotation of the fan blade assembly, thereby indicating rotational speeds of the fan.

5. The heater as claimed in claim 4, wherein the sensor is a Hall effect sensor and the device is a magnet.

6. The heater as claimed in claim 5, wherein the sensor is mounted on the control module.

7. The heater as claimed in claim 2, wherein the control module determines and stores values for the speed control relative to voltage supplied to the heater, whereby, if the closed loop feedback control fails, proper speed control is maintained by selecting a value stored for the speed control related to a particular voltage supplied to the heater.

8. The heater as claimed in claim 7, wherein the values for the speed control are continuously updated when the closed loop feedback control is operational.

9. The heater as claimed in claim 7, wherein the controller includes a pulse width modulator for controlling speed of the motor.

10. The heater as claimed in claim 1, wherein the control module includes a voltage modulator for power supply to the heater, whereby the heater operates correctly for a range of voltages supplied to the heater.

11. The heater as claimed in claim 10, wherein the voltage modulator is a pulse width modulator.

12. The heater as claimed in claim 10, wherein voltages are modulated by the modulator to a fixed voltage when the power supply to the heater is within a given voltage range.

13. The heater as claimed in claim 12, wherein the voltage range is 12-24 volts.

14. The heater as claimed in claim 13, wherein the voltage is modulated to 9 volts.

15. The heater as claimed in claim 1, wherein the speed of the motor can be adjusted, thereby adjusting the amount of heat produced by the heater.

16. The heater as claimed in claim 15, wherein the means includes a personal computer and a data link connecting the computer to the heater.

17. A heater for a liquid, the heater having a combustion chamber, a jacket for the liquid extending about the combustion chamber and a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior, a control module and a fan being mounted in the hollow interior, the fan being connected to an electric motor, a compressor and a fuel pump being mounted on the housing, the fuel pump and the compressor being operatively connected to the electric motor, the control module including controls for exercising components of the heater prior to combustion, thereby verifying operation of these components.

18. The heater as claimed in claim 17 including an ignitor for the burner, the controls operating the ignitor for a specified period of time prior to combustion.

19. A heater for a liquid, the heater having a combustion chamber, a jacket for the liquid extending about the combustion chamber and a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior, a control module and a fan being mounted in the hollow interior, the fan being connected to an electric motor, a compressor and a fuel pump being mounted on the housing, the compressor and the fuel pump being operatively connected to the electric motor, a flame sensor positioned in the housing to sense combustion in the combustion chamber, and an indicator mounted on the housing and operatively connected to the flame sensor to indicate when the flame sensor is sensing light.

20. The heater as claimed in claim 19, wherein the indicator is a light.

21. A heater for a liquid, the heater having a combustion chamber, a jacket for the liquid extending about the combustion chamber and a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior, a control module and a fan being mounted in the hollow interior, the fan being connected to an electric motor, a compressor and a fuel pump being mounted on the housing, the compressor and the fuel pump being operatively connected to the electric motor, a electric coolant pump connected to the jacket and a pump current modulator which modulates current supplied to the pump when current supply to the modulator is above a specified current and supplying an unmodulated current to the pump when current supplied to the modulator is below the specified current.

22. The heater as claimed in claim 21, wherein the modulator is a pulse width modulator.

23. The heater as claimed in claim 22, wherein the modulator modulates the current supplied to the pump to a current which is below the specified current.

24. The heater as claimed in claim 21, wherein the modulator initially supplies current to the pump for a first specified period of time, then measures the current and, if the current is above a specified level, shuts off current to the pump for a second specified period of time, then supplies current to the pump again for the first specified period of time, the modulator continuing to modulate the current in a cyclic fashion until the current is below the specified level, thereby operating as a pulse width modulator.

25. The heater as claimed in claim 22, wherein the modulator measures the current for a third specified period of time which is greater than the first and second periods of time, the controller deeming the pump to have successfully started if the current does not exceed the specified level after the third specified period of time.

26. The heater as claimed in claim 25, wherein the controller deems a pump fault to have occurred where the current exceeds the specified level after a fourth specified period of time.

27. The heater as claimed in claim 25, where the fourth period of time is greater than the third period of time.

28. A method of differentiating overcurrent faults from normal current conditions in an apparatus intended to be mounted to a vehicle and connected to the electrical system thereof, the method comprising monitoring for an overcurrent condition, monitoring voltage levels and determining whether there is a decrease in voltage relative to time exceeding a first specified value of dV/dT, or whether there is an increase in voltage relative to time exceeding a second specified value of dV/dT, declaring no overcurrent fault where there is said decrease in voltage exceeding the first specified value within a first specified time prior to an overcurrent condition or if there is an increase in voltage exceeding the second specified value within a second specified time of the overcurrent condition, and declaring an overcurrent fault where there is an overcurrent condition, but no such decrease in voltage or increase in voltage within the specified times.

29. The method as claimed in claimed 28 wherein the apparatus is a heater and the method differentiates overcurrent events resulting from the vehicle being started from overcurrent events indicating a fault.

30. An apparatus for differentiating overcurrent faults from normal current conditions in a device intended to be mounted to a vehicle and connected to the electrical system thereof, the apparatus comprising controls which monitor for overcurrent conditions, monitor voltage levels and determine whether there is a decrease in voltage relative to time exceeding a first specified value of dV/dT, or whether there is an increase in voltage relative to time exceeding a second specified value of dV/dT, declaring no overcurrent fault where there is said decrease in voltage exceeding the first specified value within a first specified time prior to an overcurrent condition or if there is an increase in voltage exceeding the second specified value within a second specified time of the overcurrent condition, and declaring an overcurrent fault where there is no such decrease in voltage or increase in voltage within the specified times.

31. The apparatus as claimed in claim 30 wherein the device is a heater and the controls differentiate overcurrent events resulting from the vehicle being started from overcurrent events indicating a fault.

32. A vehicle fitted with a fuel-powered heater for coolant, the heater having a combustion chamber, a jacket for the coolant extending about the combustion chamber and a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior, a control module and a fan being mounted in the hollow interior, the fan being connected to an electric motor, a compressor and a fuel pump being mounted on the housing, the control module including controls for differentiating overcurrent faults from normal current conditions, the controls monitoring for overcurrent conditions and voltage levels and determining whether there is a decrease in voltage relative to time exceeding a first specified value of dV/dT, or whether there is an increase in voltage relative to time exceeding a second specified value of dV/dT, declaring no overcurrent fault where there is said decrease in voltage exceeding the first specified value within a first specified time prior to an overcurrent condition or if there is an increase in voltage exceeding the second specified value within a second specified time of the overcurrent condition, and declaring an overcurrent fault where there is an overcurrent condition, but no such decrease in voltage or increase in voltage within the specified times.

33. The vehicle as claimed in claimed 30 wherein the controls differentiate overcurrent events resulting from the vehicle being started from overcurrent events indicating a fault.

34. A method for determining whether a fault has occurred in a device having a fuel burning with a flame and an ignitor for igniting the flame, the method comprising the steps of:

sensing periodically whether or not a flame is present;

registering a flame on event if the flame is present;

actuating the ignitor if no flame is present;

registering a flame out event if no flame is present after the ignitor is actuated; and

indicating that a fault has occurred when a first plurality of flame out events occurs before a second plurality of flame on events occurs.

35. The method as claimed in claim 34, wherein the method is repeated cyclically, a new cycle beginning when the second plurality of flame on events occurs before the first plurality of flame out events occurs.

36. The method as claimed in claim 35, wherein the presence of a flame is sensed once per second

37. The method as claimed in claim 36, wherein the first plurality is 10 and the second plurality is 15.

38. An apparatus for determining whether a fault has occurred in a device having a fuel burning with a flame and an ignitor for igniting the flame, the apparatus comprising:

a flame sensor which periodically senses whether or not a flame is present;

a first memory which stores a flame on event if the flame is present;

means for actuating the ignitor if no flame is present;

a second memory which stores a flame out event if no flame is present after the ignitor is actuated; and

a control device which indicates that a fault has occurred when a first plurality of flame out events occurs before a second plurality of flame on events occurs.

39. The apparatus as claimed in claim 38, wherein the sensor senses for a flame cyclically, a new cycle beginning when the second plurality of flame on events occurs before the first plurality of flame out events occurs.

40. The apparatus as claimed in claim 39, wherein the presence of a flame is sensed once per second

41. The apparatus as claimed in claim 39, wherein the first plurality is 10 and the second plurality is 15.

42. A heater for a liquid, the heater comprising a combustion chamber;

a jacket for the liquid extending about the combustion chamber;

a burner head assembly connected to the combustion chamber, the burner head assembly including a housing having a burner mounted thereon and a hollow interior;

a control module; and

a fan mounted in the hollow interior, the fan being connected to an electric motor, a compressor being mounted on the housing and operatively connected to the electric motor; and

a flame sensor for sensing the presence or absence of a flame in the combustion chamber, the control module including controls for determining whether a fault has occurred, the controls periodically checking the flame sensor to determine whether or not a flame is present, a first memory which registers a flame on event if the flame is present, the controls actuating the ignitor if no flame is present, a second memory which registers a flame out event if no flame is present after the ignitor is actuated, and the control module indicating that a fault has occurred when a first plurality of flame out events occurs before a second plurality of flame on events occurs.

43. The heater as claimed in claim 42, wherein the sensor senses for a flame cyclically, a new cycle beginning when the second plurality of flame on events occurs before the first plurality of flame out events occurs.

44. The heater as claimed in claim 43, wherein the presence of a flame is sensed once per second

45. The heater as claimed in claim 44, wherein the first plurality is 10 and the second plurality is 15.