Patent ID: 7615725
Filing Date: 2009-11-10
Classification: F02D,G01N

Abstract:
1. A heater controlling apparatus for controlling an electric heater that heats a sensing element of a gas sensor provided in an exhaust system of a diesel engine, the heater controlling apparatus comprising: information obtaining means for obtaining information used for obtaining an operational state of the exhaust system of the engine; and reference condition changing means for changing a reference condition of the electric heater in a current engine operation based on the operational state in a previous engine operation obtained before turning off of the engine in the previous engine operation; wherein the information obtaining means is temperature sensing means for sensing a temperature in the exhaust system of the engine, which temperature serves as the information used for obtaining the operational state of the exhaust system of the engine, the heater controlling apparatus further comprising: temperature increase determining means for determining whether the temperature in the exhaust system is equal to or larger than a predetermined reference temperature; high-temperature time integrating means for measuring a high-temperature integrated time in the current engine operation, the high-temperature integrated time being an integrated time, during which the temperature increase determining means determines that the temperature in the exhaust system is equal to or larger than the predetermined reference temperature; heater energization determining means for determining whether the high-temperature integrated time measured in the current engine operation is equal to or larger than a predetermined reference time; and heater energization controlling means for starting energization of the electric heater when the heater energization determining means determines that the high-temperature integrated time is equal to or larger than the predetermined reference time; and wherein the reference condition changing means changes at least one of the predetermined reference temperature and the predetermined reference time based on the operational state in the previous engine operation.