Automatic combustion control method and apparatus

A method of combustion control in a combustion system, comprising

• a combustion chamber,
• combustion means for causing the combustion of fuel in said chamber,
• a heat exchanger connecting with said combustion chamber,
• an exhaust passage connected with said heat exchanger,
• and fuel supply means for supplying fuel to said combustion means,
• said method comprising measuring the combustion temperature in said combustion chamber and producing a first quantity corresponding in magnitude with said combustion temperature,
• measuring the exhaust temperature in said exhaust passage and producing a second quantity corresponding in magnitude with said exhaust temperature,
• producing a summation of said first and second quantities and thereby producing a summation quantity,
• and varying the supply of air to said combustion means in such manner as to maximize said summation quantity,
• whereby the combustion efficiency is also maximized.

In a combustion system comprising

• combustion chamber means having a combustion chamber therein,
• heat exchanger means for deriving useful heat from said combustion chamber,
• exhaust means including an exhaust passage for removing the waste products of combustion from said combustion chamber,
• combustion means for producing a combustion of fuel in said combustion chamber,
• and fuel supply means for supplying fuel to said combustion means,
• the improvement comprising combustion temperature measuring means for measuring the combustion temperature in said combustion chamber and for producing a first quantity corresponding in magnitude with said combustion temperature,
• exhaust temperature measuring means for measuring the exhaust temperature in said exhaust passage and for producing a second quantity corresponding in magnitude with said exhaust temperature,
• summation means for producing a summation of said first and second quantities and thereby producing a summation quantity,
• a variable air valve for supplying a variable quantity of air to said combustion means to support the combustion of the fuel,
• and control means for operating said variable air valve in such a manner as to maximize said summation quantity,
• whereby the combustion efficiency is also maximized.

In a combustion system comprising combustion chamber means having a combustion chamber therein,

• exhaust means including an exhaust passage for removing the waste products of combustion from said combustion chamber, combustion means for producing a combustion of fuel in said combustion chamber,
• and fuel supply means for supplying fuel to said combustion means,
• the improvement comprising combustion temperature measuring means for measuring the combustion temperature in said combustion chamber and for producing a first quantity corresponding in magnitude with said combustion temperature,
• exhaust temperature measuring means for measuring the exhaust temperature in said exhaust passage and for producing a second quantity corresponding in magnitude with said exhaust temperature.
• summation means for producing summation of said first and second quantities and thereby producing a summation quantity,
• a variable air valve for supplying a variable quantity of air to said combustion means to support the combustion of the fuel,
• reversible power means for moving said air valve in one direction or the other to open or close said air valve,
• startup means for causing said power means to open said air valve under cold conditions while causing said power means to partially close said air valve to a startup position in response to at least one of said first and second quantities upon the attainment of a predetermined temperature level,
• operational control means for thereafter sampling said summation quantity at sampling intervals,
• storage means for storing each sampled summation quantity to provide a reference quantity,
• stepping means for causing said power means to move said air valve through a step in one direction or the other during each sampling interval to open or close the air valve by such step,
• comparison means for comparing each current summation quantity with the previous reference quantity to determine whether the current summation quantity is greater or less than the previous reference quantity,
• and direction determining means for causing said stepping means to produce movement of said air valve in the same direction as during the previous interval if the current summation quantity is greater than the previous reference quantity while causing said stepping means to move the air valve in the opposite direction relative to the preceding interval if the current summation quantity is less than the previous reference quantity,
• whereby the summation quantity and the combustion efficiency are maximized.