Valve freeze control apparatus and sensor element breakage control apparatus for internal combustion engine

A valve freeze control apparatus for an internal combustion engine comprising:

• a concentration sensor adapted to detect an alcohol concentration of fuel supplied to the internal combustion engine;
• a valve that is provided in one of an intake passage and an exhaust passage of the internal combustion engine, wherein the valve controls flow of air that passes through the one of the intake and exhaust passages;
• a passage configured to supply a part of exhaust gas to the intake passage;
• a freeze control device adapted to limit malfunction of the valve caused by freeze of water in the exhaust gas, the water having been attached to the valve;
• and
• limitation level setting means for changing a limitation level for limiting the freeze of water by controlling the freeze control device, wherein:
• the limitation level setting means increases the limitation level of the freeze more as the alcohol concentration detected by the concentration sensor indicates a higher concentration.

A sensor element breakage control apparatus for an internal combustion engine comprising:

• a concentration sensor adapted to detect an alcohol concentration of fuel supplied to the internal combustion engine;
• an exhaust gas sensor device that is provided in an exhaust passage of the internal combustion engine, wherein the exhaust gas sensor device includes:
• a sensor element adapted to sense a concentration of a specific component in exhaust gas;
• and
• an element heating device adapted to heat the sensor element;
• a breakage limiting device adapted to limit breakage of the sensor element when the element heating device is heated while water in exhaust gas is attached to the sensor element;
• and
• start determination means for determining to start the breakage limiting device when the alcohol concentration detected by the concentration sensor is equal to or greater than a reference value.

A sensor element breakage control apparatus for an internal combustion engine comprising:

• a concentration sensor adapted to detect an alcohol concentration of fuel supplied to the internal combustion engine;
• an exhaust gas sensor device that is provided in an exhaust passage of the internal combustion engine, wherein the exhaust gas sensor device includes:
• a sensor element adapted to sense a concentration of a specific component in exhaust gas;
• and
• an element heating device adapted to heat the sensor element;
• a breakage limiting device adapted to limit breakage of the sensor element when the element heating device is heated while water in exhaust gas has been attached to the sensor element;
• and
• limitation level setting means for changing a limitation level for limiting the breakage of the sensor element by controlling the breakage limiting device, wherein:
• the limitation level setting means increases the limitation level of the breakage more as the alcohol concentration detected by the concentration sensor indicates a higher concentration.