Microprocessor controller for diesel fuel fired heater

In a diesel heater including a combustion chamber, fuel pumping means for pumping diesel fuel to said combustion chamber, combustion air supplying means;

• for supplying combustion air to said combustion chamber, igniting means for igniting said diesel fuel to generate combustion heat, a heat exchanger for receiving the heated combustion air and having coolant flowing therethrough in heat exchange relationship with the heated combustion air, a coolant system connected to said heat exchanger for providing coolant thereto, coolant pumping means for pumping said coolant through said heat exchanger and said coolant system, a thermal sensor in contact with said coolant, and flame detecting means for detecting an ignited flame and for generating a flame signal in response thereto, an improvement comprising:
• a microprocessor including a memory and a plurality of input/output ports wherein said input/output ports are connected to said thermal sensor, said fuel pumping means, said coolant pumping means, said igniting means, said combustion air supplying means, and said flame detecting means, and wherein said memory stores a start-up sequence;
• and
• input means for entering a low temperature setpoint for said coolant into said microprocessor memory,
• wherein said microprocessor activates said coolant pumping means for a first period when said coolant temperature falls below said low temperature setpoint before initiating said start-up sequence to ensure uniform temperature of the coolant in the heat exchanger and the coolant system, and
• wherein said microprocessor initiates said start-up sequence if said coolant temperature is below said low temperature setpoint after said coolant pumping means was activated for said first period.

In a diesel heater including a combustion chamber, fuel pumping means for pumping diesel fuel to said combustion chamber, combustion air supplying means for supplying combustion air to said combustion chamber, igniting means for igniting said diesel fuel to generate combustion heat, heat exchange fluid pumping means for pumping a fluid in heat exchange relationship with said combustion heat, an engine including a battery and a heat exchange system in fluid communication with said heat exchange fluid pumping means, a thermal sensor in contact with said heat exchange fluid for generating a temperature signal proportional to a temperature of said heat exchange fluid, and flame detecting means for detecting an ignited flame and for generating a flame signal in response thereto, an improvement comprising:

• a microprocessor including a memory, a plurality of input/output ports, and a display,
• wherein said input/output ports are connected to said thermal sensor, said fuel pump means, said heat transfer fluid pumping means, said igniting means, said combustion air supplying means, and said flame detecting means,
• wherein said memory stores a normal operating sequence, and a start-up sequence, and
• wherein said microprocessor memory stores a purge sequence and said microprocessor executes said purge sequence when said microprocessor detects a voltage input from the battery less than an operating voltage threshold during said normal operating sequence.

In a diesel heater connected to a cooling system of a diesel engine of a vehicle including a passenger cab, the diesel heater including a combustion chamber, fuel pumping means for pumping diesel fuel to said combustion chamber, combustion air supplying means for supplying combustion air to said combustion chamber, igniting means for igniting said diesel fuel to generate combustion heat, heat exchange fluid supplying means for supplying a fluid from the cooling system of the diesel engine in heat exchange relationship with the combustion heat, a thermal sensor in contact with said heat exchange fluid for generating a temperature signal proportional to a temperature of said heat exchange fluid, and flame detecting means for detecting an ignited diesel fuel flame and for generating a flame signal in response thereto, an improvement comprising:

• a microprocessor including a memory and a plurality of input/output ports wherein said input/output ports are electrically connected to said thermal sensor, said fuel pump means, said heat transfer fluid supplying means, said igniting means, said combustion air supply means, and said flame detecting means and wherein said memory stores a normal operating sequence and a start up sequence;
• cab temperature sensing means for sensing temperature in said passenger cab;
• cab heating means connected to said heat exchange fluid supplying means for actuating a fan to direct air into heat exchange relationship with said heated fluid from said heat exchange fluid supplying means;
• and
• input means for setting a cab temperature setpoint in said microprocessor memory, wherein said microprocessor is connected to said cab temperature sensing means and said cab heating means, and
• wherein said microprocessor actuates said cab heating means during said normal operating mode to maintain said cab temperature at said cab temperature setpoint.

A method of starting a diesel fuel fired heater comprising the steps of:

• a) starting a first timing means for timing first, second, third and fourth periods;
• b) energizing an igniting means for igniting diesel fuel supplied to a combustion chamber and starting said timing means;
• c) energizing a combustion air supply means for supplying combustion air to said combustion chamber after said first period:
• d) operating a fuel pumping means for pumping diesel fuel to said combustion chamber at a first frequency after said second period;
• e) starting a second timing means for timing a fifth period and stopping said fuel pump means;
• f) operating said fuel pumping means at a second frequency after said third period;
• g) starting a third timing means for timing a sixth period after said fifth period;
• h) stopping said fuel pumping means after said sixth period;
• i) starting a fourth timing means for timing a seventh period;
• j) operating said fuel pumping means after said seventh period;
• and
• k) starting said third timing means.