Combustion control system
AssigneeThe Foxboro Company
InventorsJames E. Shriver, David P. Dickhaut
Life of this patent
Estimating the term…
Abstract
In a combustion system, the economic optimum efficiency is achieved by periodically computing a relative index of combustion efficiency using the combustion chamber as a real-time, on-line calorimeter. This is accomplished by first determining the combustion chamber inputs and outputs required to calculate a relative index of performance (including measuring the amount of heat released or work performed at the present air/fuel ratio including the stack losses, without oxygen and/or carbon monoxide sensors), sequentially comparing the latest relative index value with the previous value, then adjusting the air/fuel ratio to achieve an improved index value.
Claims30
In a combustion system having a combustion chamber, controllable fuel inputs and/or air inputs, an exhaust outlet path, heat absorbing means, and means for measuring the temperature of combustion products in the exhaust outlet path, the method of controlling the air/fuel ratio input to the combustion system without measuring the oxygen or carbon monoxide in the exhaust outlet path, comprising the steps of:
- (a) determining, as the absorbed net heat released, the total heat release which is absorbed by the heat absorbing means;
- (b) determining the stack heat losses as measured by said means for measuring the temperature of combustion products in the exhaust outlet;
- (c) determining the net heat released by the combustion process by summing the absorbed net heat release and the stack heat losses;
- (d) calculating a first and at least one successive relative index value related to the absorbed net heat release from the combustion system;
- (e) identifying from comparison of each successive index value with the previous index value the relative index value having the greatest magnitude;
- and
- (f) adjusting the air/fuel input ratio to the combustion system in an amount to optimize the combustion process according to the relative index value of greatest magnitude.
A combustion system having a combustion chamber, controllable fuel inputs and/or air inputs, an exhaust outlet path, heat absorbing means, and means for measuring the temperature of combustion products in the exhaust outlet path, apparatus for controlling the air/fuel ratio input to the combustion system without measuring the oxygen or carbon monoxide in the exhaust outlet path, comprising:
- (a) means for determining, as the absorbed net heat release, the total heat release whcih is absorbed by the heat absorbing means;
- (b) means for determining the stack heat losses as measured by said means for measuring the temperature of combustion products in the exhaust outlet;
- (c) means for determining the net heat released by the combustion process including the absorbed net heat release and the stack heat losses as measured by said means for measuring the temperature of combustion products in the exhaust outlet;
- (d) means for calculating a first, relative index value related to the absorbed net heat release from the combustion system and successive relative index values;
- (e) means for identifying from comparison of each successive index value with the previous index value the relative index value having the greatest magnitude;
- and
- (f) means for adjusting the air/fuel input ratio to the combustion system in an amount to optimize the combustion process according to the relative index value of greatest magnitude.
A combustion system having a combustion chamber, controllable fuel inputs and/or air inputs, an exhaust outlet path, heat absorbing means, and means for measuring the temperature of combustion products in the exhaust outlet path, apparatus for controlling the air/fuel ratio input to the combustion system without measuring the oxygen or carbon monoxide in the exhaust outlet path, comprising:
- (a) means for determining the net heat inputs to the combustion chamber;
- (b) means for determining, as the absorbed net heat release, the total heat release which is absorbed by the objective process;
- (c) means for determining the stack heat losses as measured by said means for measuring the temperature of combustion products in the exhaust outlet;
- (d) means for determining the net heat released by the combustion process by summing the net heat inputs to the combustion chamber, the absorbed net heat release, and the stack heat losses as measured by said means for measuring the temperature of combustion products in the exhaust outlet;
- (e) means for calculating a first, relative index input related to the absorbed net heat release from the combustion system and successive relative index values;
- (f) means for identifying from comparison of each successive index value with the previous index value the relative index value having the greatest magnitude;
- and
- (g) means for adjusting the air/fuel input ratio to the combustion system in an amount to optimize the combustion process according to the relative value of greatest magnitude.
Dependencies are inferred from the claim text.