An air amount calculation device is configured to receive a detection signal from an air amount sensor provided in an intake air passage of an engine and to calculate an air amount of air flowing through the intake air passage based on the detection signal. The air amount calculation device includes: an acquisition unit configured to acquire an air amount calculation parameter using a detection point within an intermediate range intermediate between a maximum value and a minimum value in the detection signal; and an air amount calculation unit configured to calculate the air amount based on the air amount calculation parameter.

An intake pressure sensor is provided in an intake path of a single cylinder engine and detects an intake pressure. A crank angle sensor detects a crank angle of the single cylinder engine. A sampling unit samples the intake pressure detected by the intake pressure sensor when the crank angle detected by the crank angle sensor becomes a sampling start angle. A calculation unit extracts M intake pressures of relatively small values of N intake pressures sampled by the sampling unit. The calculation unit acquires, as a bottom pressure, an average value of P intake pressures remaining after several intake pressures of relatively large values and several intake pressures of relatively small values of the M intake pressures are excluded.

In order to adequately suppress both an increase in NOx emission amount and deterioration of fuel consumption rate, the present invention provides a fuel injection control information generation device equipped with: a test point information storage unit for holding test point information including a plurality of test points constituted by sets of engine speed, fuel injection amount, and oxygen concentration; and a control information generation unit for generating, for each test point included in the test point information, fuel injection control information in which the engine speed, fuel injection amount, and oxygen concentration of the test point are associated with an optimum fuel injection timing at which an index pertaining to the total of a fuel consumption rate and an NOx emission amount in the test point becomes the smallest.

Please substitute the new Abstract submitted herewith for the original Abstract: A method for determining a fresh-air-mass parameter in a cylinder of an internal combustion engine in a motor vehicle includes identifying a cylinder which is at the end of an intake stroke or at the beginning of a compression stroke during operation of the motor vehicle, determining a diagnosis time window which lasts for a period of time after closing of the inlet valves of the identified cylinder within a region of low torque of the internal combustion engine, ascertaining a development in the speed of the internal combustion engine during the diagnosis time window, and determining the fresh-air-mass parameter in the identified cylinder.

A physical quantity measurement device is configured to seal a cavity portion on a back surface side of a diaphragm of a thermal air flow rate sensor while improving measurement accuracy. The device may include a lead frame having a mounting surface on which a flow rate sensor which is the thermal air flow rate sensor is mounted, and a flow passage forming member disposed on a back surface opposite to the mounting surface of the lead frame. A ventilation flow path is formed by a first through hole in communication with a cavity portion of the flow rate sensor, a second through hole provided in the lead frame and opened in the mounting surface, and a connection flow path that is defined between the lead frame and the flow passage forming member and connecting the first through hole and the second through hole.

A method for adjusting a fuel mass to be injected into an internal combustion engine. The internal combustion engine including an intake tract, at least one cylinder, and an exhaust tract. In the method, an air mass introduced into the internal combustion engine is ascertained and a fuel mass to be injected into the internal combustion engine is determined. An air-fuel ratio in the exhaust tract of the internal combustion engine is determined which is adjusted in time. Based on the time-adjusted air-fuel ratio and the calculated fuel mass to be injected, a first wall film fuel mass is calculated and the fuel mass to be injected is adjusted based on the first wall film fuel mass.

A controller for an electronic fuel injection system for an internal combustion engine includes: a plurality of analog-to-digital (A/D) converters; a memory; and a processor communicatively coupled to the A/D converters and the memory. The A/D converters are configured to receive analog electrical signals representing pressures generated by a plurality of pressure sensors disposed at different locations along an air intake path and output corresponding digital signals representing the pressures, one or more of the pressure sensors are disposed in a body of a carburetor rendered permanently inoperable to mix fuel with air flowing in the air intake path, and the processor is configured to receive the digital signals representing the pressures output from the A/D converters and output a mass air flow signal representing a mass air flow rate as to an engine management system to control the electronic fuel injection system based on the received pressure signals.

Provided are a control device for an internal combustion engine, wherein the internal combustion engine is provided with a crank mechanism for converting a reciprocating motion of a piston into a rotating motion of a crankshaft, a cylinder accommodating the piston, and an intake valve capable of opening and closing an inlet for sucking gas into the cylinder, and the control device is provided with: a volumetric efficiency calculating unit for calculating a volumetric efficiency representing a suction efficiency when gas is sucked into the cylinder, on the basis of a cylinder capacity when the intake valve is closed; a gas suction amount calculating unit for calculating a gas suction amount sucked into the cylinder, by means of a predetermined formula, on the basis of the calculated volumetric efficiency; and a control unit for controlling the internal combustion engine on the basis of the calculated gas suction amount.

A cold air intake system is provided for actively controlling airflow based upon user input and/or demand conditions. Two air inlets are provided into a sealed air box with the secondary air intake including an air control valve for modulating intrusion of intake air. The valve has a valve seat formed the housing sidewall and a flap door valve member actively actuated via a controller. The mass air flow sensor indicates total demand. A pressure sensor and a temperature sensor provide additional input from the airbox. The controller modifies the valve position based upon pressure, temperature and mass air flow. Control is biased to increase secondary air intake when airbox pressure decreases and biased to decrease secondary air intake when airbox temperature increases. Controller biasing occurs between 30 F. to 160 F. and over pressure ranges between 0.01 H.sub.2O to 5 H.sub.2O.

A port injection valve injects fuel into an intake passage. A controller increases a base injection amount over a predetermined period after the internal combustion engine is started and gradually decreases an increase correction ratio of the base injection amount. One of two processes, a multiple injection process and a single injection process, is selected in order to inject the increased base injection amount of fuel. The increase correction ratio is set to be a smaller value in the multiple injection process than in the single injection process.