Abstract: A throttle valve switch unit for use with a throttle valve situated in an internal combustion engine. A mobile contact is drivingly connected to the throttle valve for movement with rotation of the throttle valve. The mobile contact is engageable with at least two fixed contacts. The first fixed contact is placed for engagement with the mobile contact when the throttle valve occupies a first predetermined position. The second fixed contact is placed for engagement with the mobile contact when the throttle valve occupies a second predetermined position. The first fixed contact is connected through a first resistance element to one of a first terminal for connection to the ground and a second terminal for connection with a source, of voltage. The second fixed contact is connected to the one terminal through a second resistance element having a resistance value different from that of the first resistance element. The mobile contact is connected to the other terminal through a third resistance element.

Abstract: With engine control apparatus for controlling a throttle opening and fuel injection quantity in order to realize a target engine torque according to the present invention, in the case where a target air-fuel ratio is changed in accordance with a change in the target engine torque, erroneous control of the fuel injection quantity is prevented.To achieve this, a target fuel quantity and a target air-fuel ratio are set based on the target engine torque, and a target air quantity is computed from the target fuel quantity and the target air fuel ratio. A target throttle opening is then computed based on the target air quantity, to control an electrically controlled throttle valve. Meanwhile, an actual air quantity detected by an air flow meter is smoothed, and a cylinder charge air quantity computed. The target air-fuel ratio is then corrected using a ratio of the cylinder charge air quantity to the target air quantity.

Abstract: A pull-down resistor is connected to a power source line between power source connectors and a detector circuit in an apparatus in which a power source is connected via the power source connectors to the detector circuit, which includes a temperature-sensitive resistor and which outputs a voltage signal to a control unit via signal connectors. The pull-down resistor increases current flow to the power source connectors thus to suppress oxide formation thereon. A pull-up resistor or a pull-down resistor is connected to a signal line between the signal connectors and a filter circuit in the control unit, in order to increase an electric current that flows into the signal connector terminals thereby to prevent the formation of an oxide film on the signal connector terminals.

Abstract: The invention relates to technology for avoiding the influence of intake air volumetric flow rate changing due to contamination of a throttle valve opening. When the opening of the throttle valve of an internal combustion engine is large, the atmospheric pressure is estimated based on, the intake air volumetric flow rate which is estimated based on the throttle valve opening, and on a separately detected intake air mass flow rate. After this, within a predetermined time for example, when the opening of the throttle valve changes to a small opening while the atmospheric pressure is virtually constant, the atmospheric pressure is similarly estimated based on the estimated intake air volumetric flow rate and on the detected intake air mass flow rate.

Abstract: A fuel injection control system for an internal combustion engine equipped with a fuel injection system includes fuel injector valves. The fuel injection control system comprises a control unit for controlling fuel injection for each fuel injector valve. The control unit has a function to control the fuel injection in accordance with a first characteristic required for engine starting before occurrence of an initial explosion in an engine cylinder, and in accordance with a second characteristic required for normal engine operation after occurrence of the initial explosion.