Abstract: An intake air temperature detected by an airflow sensor is corrected based on a rotation speed of an engine and a fuel supply amount to thereby estimate an atmospheric temperature. The atmospheric temperature is estimated by calculating a dynamic temperature error caused by heat generated around an engine and a correction factor in regard to thermal influence which changes according to the flow rate of an intake air, and correcting the intake air temperature detected by the airflow sensor with the temperature error corrected with the correction factor. On the basis of the atmospheric temperature, an electric heater is controlled, which is provided on at least a part of a system of supplying a reducing agent or its precursor, for example, a supply pipe mutually communicating a reducing agent container with a reducing agent supplying apparatus.

Abstract: In a flow quantity measuring device, each of upstream side and downstream side sensing resistors, which are placed on an upstream side and a downstream side, respectively, of a heating resistor, includes resistor elements, each of which forms a folded path. The folded path has a generally constant width along an entire extent thereof and is returned at each of first and second longitudinal end edges of a sensing area. The heating resistor forms a folded path, which has a generally constant width along an entire extent thereof and is returned at the second longitudinal end edge of the heat generating area. First and second ends of the folded path of the heating resistor projects beyond the first longitudinal end edge of the sensing area on a first side of the flow quantity measuring device.

Abstract: To reduce power consumption by a thermal flowmeter while good flow-rate detection sensitivity is maintained, it is only necessary to reduce power consumption by a heat resistor under predetermined conditions. Specifically, provided that a width Wh of the heat resistor is between 100 micrometers and 400 micrometers inclusive (100?Wh?400), it is only necessary that a relationship among the length Lh of the heat resistor, a temperature increase ?Th for the heat resistor, and a maximum permissible power Phmax to be supplied to the heat resistor be set so as to satisfy a formula 1.4??Th·Lh/Phmax?2.8 in order to maintain good flow-rate detection sensitivity. Accordingly, the length of the heat resistor and the temperature increase in the heat resistor are set so that the maximum power consumption can be reduced within a range in which the formula is satisfied.

Abstract: When it is predicted that an engine is going to be started in the near future, a heater portion of an air flow meter is energized so as to be heated in advance. Prior to the pre-heating, an intake air temperature is sensed by a temperature sensing portion of the air flow meter. After completion of start-up of an intake air temperature sensor, a difference between the intake air temperature sensed by the intake air temperature sensor and the previously sensed intake air temperature is obtained. When the difference is above a predetermined value, it is judged that the intake air temperature sensor or the air flow meter is in an abnormal condition.

Abstract: A method for operating an internal combustion engine, in which an engine temperature and an intake air temperature are ascertained. In the operating method described, a plausibility check of the engine temperature is performed using the intake air temperature and/or a plausibility check of the intake air temperature is performed using the engine temperature. Furthermore, a control unit for an internal combustion engine as well as a computer program for a control unit of an internal combustion engine and an internal combustion engine are described.