Abstract: Disclosed herein is an evaporative emission control system which can prevent changes in fuel component in the fuel tank and vacuum boiling in the fuel pump to thereby accurately control the air-fuel ratio to a desired value and ensure smooth supply of the fuel. The control system includes an evaporative fuel passage for connecting a fuel tank and an intake system of an internal combustion engine, and a control valve is provided in the evaporative fuel passage for opening and closing the evaporative fuel passage. It is determined whether or not a fuel temperature is higher than or equal to a predetermined fuel temperature. If the fuel temperature is higher than or equal to the predetermined fuel temperature, the opening operation of the control valve is disabled.

Abstract: Disclosed herein is an evaporative emission control system which can prevent changes in fuel component in the fuel tank and vacuum boiling in the fuel pump to thereby accurately control the air-fuel ratio to a desired value and ensure smooth supply of the fuel. The control system includes an evaporative fuel passage for connecting a fuel tank and an intake system of an internal combustion engine, and a control valve is provided in the evaporative fuel passage for opening and closing the evaporative fuel passage. It is determined whether or not a pressure in the tank is higher than or equal to a pressure value obtained by adding a pressure in the intake system. If the pressure in the tank is higher than or equal to the pressure value, the opening operation of the control valve is enabled.

Abstract: Disclosed herein is an evaporative emission control system which can properly control the ratio between a tank purge amount and a canister purge amount to realize quick pressure reduction in a fuel tank and ensuring the storage capacity of a canister in a well balanced fashion. A target pressure in controlling the pressure in the fuel tank at a negative pressure and a detected pressure in the fuel tank are compared with each other. When the difference between the target pressure and the detected pressure is large, tank purge is preferentially carried out to open a tank pressure control valve. When the detected pressure is in the vicinity of the target pressure, canister purge is preferentially carried out to purge the evaporative fuel stored in the canister.

Abstract: A control device for controlling an air-to-fuel ratio when fuel is injected in an internal combustion engine, comprises: a state detecting unit for detecting parameters representing operating states of the internal combustion engine; a counting unit for counting the number of times of explosion in a cylinder just after the engine starts; and a unit for estimating an air-to-fuel ratio just after the engine starts from the operating state parameters and the number of times of explosion.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor for detecting the air-fuel ratio of exhaust gases from the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer based on a model representative of the behavior of the exhaust system. Cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders are calculated for carrying out feedback control of the air-fuel ratio of the mixture such that each of the estimated air-fuel ratio is converged to a desired value.

Abstract: An air-fuel ratio control system for an internal combustion engine has a sensor which detects the air-fuel ratio of exhaust gases in an exhaust passage of the engine emitted from a plurality of cylinders. An air-fuel ratio of a mixture supplied to each of a plurality of cylinders is estimated, based on the detected air-fuel ratio and a model representative of a behavior of the exhaust passage. A cylinder-by-cylinder air-fuel ratio control amount is calculated for use in controlling the air-fuel ratio of the mixture supplied to the each of the cylinders in a feedback manner responsive to the estimated air-fuel ratio of the mixture such that the estimated air-fuel ratio of the mixture supplied to the each of the cylinders is converged to a desired air-fuel ratio. A learned value of the cylinder-by-cylinder air-fuel ratio control amount is calculated.

Abstract: A programmable controller comprises an input circuit including a plurality of signal input terminals which receive signals from a plurality of external input devices, and a power feed terminal and a ground terminal which are respectively exposed in order to supply a power source voltage from outside the programmable controller. Also, current regulator elements are respectively located between the power feed terminal or the ground terminal and the plurality of signal input terminals. Owing to this construction, the range of power source voltages to be supplied to the input circuit can be widened, and various external input devices can be connected without altering internal circuitry. A plurality of power sources of fixed voltages which are generally used are built in, whereby a user need not especially prepare a power source and can be freed from the labors of wiring etc.

Abstract: Disclosed herein is a programmable controller comprising a central processing unit (CPU) and a delay element. The CPU operates on simulated input information in accordance with a sequence program. The result of the operation by the CPU is sent to the delay element. The delay element in turn supplies the operational result with a delay time setting and feeds the result back to the CPU as simulated input information. The delay element is also capable of setting any delay time for simulation as desired.

Abstract: In processing a sequence program for a normally closed contact, the input signal is logically inverted before processing, inversion not being required for a normally open contact. A logical inversion circuit is provided for logically inverting an input signal corresponding to the normally closed contact designation of the sequence program before the input signal is fed to a central processing unit, so that inversion processing in the central processing unit can be dispensed with and the operation speed can be increased. The application of a logical inversion signal to the logical inversion circuit can readily be effected by utilizing an address line of the central processing unit.

Abstract: Machine language instructions corresponding to sequence instructions that are stored in a first memory are stored at addresses of a second memory corresponding to operating codes of the sequence instructions, and a processing unit executes a sequence control by the instructions fetched from the second memory. A jump instruction with non-designated jump-to address is stored in the second memory. Following fetching of the jump instruction from the second memory, the processing unit fetches the sequence instruction to be next executed from the first memory, and the operation code of that sequence instruction is transferred to the processing unit as a jump-to address of the jump instruction.

Abstract: In a sequence controller, a sequence program store device includes an instruction store unit for writing a specific instruction dedicated to the sequential control and a plurality of latch circuits respectively associated with the outputs from an output unit. The latch circuits are controlled by a signal from a processing device which periodically calls and processes the program from the store device and executes a specific output processing when external input signals satisfy a logical state set by the program; the latch circuits, if a transition condition of the program is satisfied when the specific instruction is processed, retain an output state of the output unit until the next transition condition is satisfied, and release the state retaining the output state before the next transition condition is satisfied.

Abstract: Each of a plurality of input/output units (2, 3) connected to an arithmetic control unit (1) is provided with a selection latch circuit (23, 33). The selection latch circuits are connected in series in such a manner that the output (25) of the selection circuit of a certain input/output unit (2) is connected to the input of the selection circuit (33) of the succeeding-stage unit (3). When a selection signal is sent to the input/output unit arranged near to the arithmetic control unit (1), the input/output unit is addressed by the output of the selection latch circuit, and simultaneously, the signal is transmitted to the selection latch circuits provided in the succeeding-stage input/output circuits.