Vehicle heater and controls therefor

a technology for heaters and vehicles, applied in the field of heaters, can solve the problems of insufficient speed control of motors, difficult starting, and inability to provide a comfortable interior temperatur

Inactive Publication Date: 2005-02-24
TELEFLEX CANADA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0028] A closed loop control system can provide the type the speed control described above. However the invention advantageously has a backup system utilizing a lookup table which is utilized if the closed loop system becomes dysfunctional. This provides an extra degree of reliability and safety.
[0030] Also the invention permits the control module to exercise selective heater components prior to combustion. This allows a service technician to directly observe and verify operation of these loads. This facilitates troubleshooting and eliminates the requirement for special test tools.
[0032] The invention also protects the coolant pump from overcurrents without unnecessarily using soft starts. Soft starts may cause chatter of the motor relay and lessen relay life. The invention is capable of selectively using soft starts only when required, thus lengthening relay life.
[0033] The invention reduces the possibility of false overcurrent faults being indicated. In general all circuits have current limits for protecting components such as the motor. However false overcurrent readings can be triggered by rapid voltage changes when the engine of the vehicle is cranked and subsequently when the engine starts and the alternator commences operation. The invention is able to distinguish between the engine starting scenario and a true overcurrent fault.

Problems solved by technology

This is particularly important for diesel-powered vehicles which are often difficult to start due to low volatility of the fuel.
Heaters relying solely on the engine coolant as heated by the engine may be insufficient to provide a comfortable interior temperature.
Typical prior art vehicle heaters employ fans with motors which lack speed control.
Thus a steady output from the heater is not assured.
Manufacturers have had to supply completely different heaters for these different heating requirements and this increases the cost of manufacture as well as the complexity and cost of warehousing and handling different models of heaters.
Another problem associated with prior art vehicle heaters is troubleshooting techniques.
These heaters do not allow for easily testing and diagnosing of problems arising with various components of the heater.
One problem encountered with prior art heaters is ascertaining whether or not proper combustion is occurring.
It is desirable to remove the sight glass in order to simplify the construction of the heater, but this leaves a problem of how to properly check the flame.
However such a soft start may cause chattering of the relay associated with the motor.
Eventually such a relay fails.
However false error readings can result from starting the vehicle.
When the ignition of the vehicle is first engaged, the starter motor starts and causes a voltage drop.
This causes a sharp voltage rise.
The result can be a false indication that an overcurrent fault has occurred.
Another associated problem relating to prior art vehicle heaters is flame sputtering.
As a certain point, however, the lack of fuel may indicate a fuel leak or other fault in the fuel system requiring the heater to be shut down.
Some prior art heaters do not have adequate means for distinguishing between occasional bubbles in the fuel and more serious problems.

Method used

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  • Vehicle heater and controls therefor

Examples

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Embodiment Construction

[0065] Referring to the drawings, and first to FIG. 1, this shows a transit heater 30 according to an embodiment of the invention. The heater includes a heat exchanger 32 equipped with a primary temperature sensor 34 and a secondary temperature sensor 36. The latter is optional as described below. There are fittings 40 and 42 which serve as inlets and outlets for liquid, a mixture of water and anti-freeze being the usual liquid for a transit vehicle heater. Mounting brackets 44 and 46 are connected to the heat exchanger for mounting the heater on a transit vehicle or similar application. A combustion tube 48 fits within the heat exchanger and a burner head assembly 50 fits over the combustion tube. The assembly is secured to the heat exchanger by bolts 52 and 54.

[0066] The burner head assembly is shown in better detail in FIGS. 2 and 3. The assembly includes a burner head assembly housing 51, cylindrical in this example, having two portions, a blower housing 56 and a head flange as...

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PUM

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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.

Description

BACKGROUND OF THE INVENTION [0001] This invention relates to heaters, in particular to heaters for heating the coolant of vehicles and to controls therefor. [0002] Fuel-powered vehicle heaters are used for two main purposes. The first purpose is to heat the coolant of the vehicle so the vehicle is easier to start in cold climates. This is particularly important for diesel-powered vehicles which are often difficult to start due to low volatility of the fuel. However these heaters have a second important function, particularly for transit vehicles such as buses. Heaters relying solely on the engine coolant as heated by the engine may be insufficient to provide a comfortable interior temperature. Accordingly, fuel-powered heaters may be used to supplement the heat by providing additional heat to the coolant. [0003] Fuel-powered vehicle heaters conventionally include a combustion chamber surrounded by a coolant jacket where the coolant is heated by combustion of fuel in the combustion c...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): F27D99/00F23N3/08
CPCB60H1/2206B60H1/2209F23N3/082F23N2041/14F23N2023/08F23N2031/10F23N2033/08F23N2023/04F23N2223/04F23N2223/08F23N2231/10F23N2233/08F23N2241/14F23N5/203F23N2227/10
InventorYOUNG, JONATHANPAUL, DOUGLAS THOMPSONFACCONE, ANGELO
OwnerTELEFLEX CANADA