Abstract: A semi-closed type of breathing apparatus includes an air exhaling duct for guiding breathing air exhaled from a mouthpiece to a canister filled with a carbon dioxide remover, and an air inhaling duct for guiding the breathing air, from which carbon dioxide has been removed, to the mouthpiece. The air inhaling duct and the air exhaling duct are designed in a double-duct structure such that the air inhaling duct is surrounded by the air exhaling duct. That is, the ducts are formed in a single hose. Therefore, detachment of the breathing apparatus from a user is easily performed, the overall appearance of the apparatus is not marred, and the entire construction of the apparatus is simplified.

Abstract: For supplying fuel from a fuel tank to an internal combustion engine by a fuel supply pump, a fuel delivery pressure of the fuel supply pump is regulated by a pressure regulating valve so as to maintain the difference between the fuel delivery pressure of the pump and an inner pressure of an intake manifold of the engine at a prescribed constant value, and the delivery volume of fuel from the pump is controlled in response to the fuel delivery pressure so as to minimize the amount of surplus fuel produced by the pressure regulating operation of the pressure regulating valve.

Abstract: In the closed-loop control system responsive to an average speed of a multi-cylinder internal combustion engine for obtaining a target idling engine speed, there is provided an optically activatable individual cylinder control system for eliminating the difference between the outputs of the respective cylinders. The closed-loop control system has a data processing circuit for processing control data for the closed-loop control system and enabling the use of the closed-loop control system for at least proportional and integral control, and the control constant used in the data processing circuit is changed depending upon whether or not the individual cylinder control system is used, whereby stable individual cylinder control can be realized.

Abstract: In an idling operation controlling apparatus for performing an individual cylinder control of a multi-cylinder internal combustion engine, individual cylinder control data is corrected only during a predetermined period in accordance with a predetermined parameter relating to the state of the control of the amount of fuel injection of the internal combustion engine, in such a way that the time period required for the regulation of the injection quantity for each cylinder to reach a desired state is shortened, thus the response characteristic of the individual cylinder control system can be improved.

Abstract: In an individual cylinder control apparatus having a closed-loop control system for controlling an average speed of an internal combustion engine, the operation timing of the engine is detected and a timing signal for each cylinder, showing a predetermined measurement period determined to include at least that part of the period during which torque is produced due to fuel combustion in the cylinder concerned during which no influence arises because of torque produced in cylinders other than the cylinder concerned, is output in response to the result of the detection. In response to the timing signal, difference data representing the difference between the output from each cylinder and that from a predetermined reference cylinder among the cylinders is calculated.

Abstract: An idling operation control apparatus consists of a closed-loop control system responsive to an average speed of a multi-cylinder internal combustion engine for obtaining a target idling engine speed. In the closed-loop control system, there is provided an individual cylinder control system in which a first data relating to outputs of respective cylinders of the engine is produced in response to an operation timing of the engine and the differential data showing the difference between the output of the respective cylinder and the output of a reference cylinder is calculated on the basis of the first data. A second control data relating to the fuel amount necessary for nullifying the difference indicated by the differential data is also produced in the latter system and the second data is supplied to the closed-loop control system, whereby the difference among the outputs of the cylinder is reduced.

Abstract: In an control apparatus for controlling a timing of injection of fuel to be injected into an internal combustion engine, the apparatus comprises a closed loop system in which the data showing the actual timing of injection of of fuel is fed back. When the condition of the operation of the engine becomes a predetermined state, the control system is changed from the closed loop system to another system in which an adjusting member for adjusting the timing of injection of fuel is controlled by a signal which is not related to the actual timing of injection. As a result, the stability of the operation in low engine speed zone is remarkably improved.

Abstract: A circuit for generating a position signal has a detector having a detecting coil whose inductance varies in accordance with the position of an object which generates a first pulse response signal relating to the inductance of the detecting coil in response to the pulse signal, another detector having a constant inductance coil which generates a second pulse response signal relating to the inductance of the constant inductance coil in response to the pulse signal, and a circuit for producing a digital signal showing the ratio of the inductances of the detecting coil and the constant inductance coil as position data in response to at least the first and the second pulse response signals. The position signal can be directly obtained in digital form and the change in the inductances due to temperature change can be canceled out to obtain position data with high accuracy.

Abstract: In an apparatus for controlling the fuel injection advance angle of a fuel injection pump having a hydraulic type timer with a solenoid valve, the apparatus has a closed-loop control system in which the solenoid valve is controlled so as to be closed or opened in accordance with a first control signal produced in response to a feedback signal showing the actual injection advance angle so that the actual injection advance angle is made to coincide with a desired target injection advance angle when the feedback signal is in a predetermined condition, and the solenoid valve is controlled by a second control signal in the open-loop control mode so as to be continuously closed/opened whereby to regulate the average opening degree of the solenoid valve in order to obtain the optimum injection advance angle when the feedback signal is not in the predetermined normal condition.

Abstract: In a fuel injection advance angle measuring apparatus, in which the advance angle is measured on the basis of an injection timing signal produced from, such as, a needle valve lift sensor and a reference timing signal indicative of the reference timing of the engine rotation, in order to remove the noise signal from the signal from the sensor, a masking signal indicating a predetermined period in which the desired component of the injection timing signal is not to be produced, is generated in response to the injection timing signal and the reference timing signal whereby to eliminate the undesired components of the injection timing signal for the measurement of the fuel injection advance angle and to obtain the fuel injection advance angle with high accuracy in measurement.

Abstract: In a characteristic signal generator for producing a characteristic signal determined from a characteristic curve for the maximum amount of fuel to be injected into an internal combustion engine from an electronically controlled fuel injection pump, the generator has a memory in which a plurality of sets of characteristic data each representing a characteristic curve for the maximum amount of fuel to be injected are stored, and the necessary data is read out from the memory in response to the data relating to the engine speed at each instant.

Abstract: In an electronically controlled fuel injection apparatus which is controlled in accordance with the signal from a sensor for providing a signal concerning the operational condition of the associated engine, there are provided a generator for generating a stand-by signal by which the apparatus is able to continue the control operation thereof without the normal output signal from the sensor and a switching circuit for applying the stand-by signal instead of the signal from the sensor to a control section for electronically controlling the apparatus in response to detecting the occurrence of trouble in the sensor.

Abstract: In a timing control device of a fuel injection pump which is so arranged that the fuel injection timing is adjusted in accordance with the duty ratio of a driving pulse signal applied to a timing valve, the frequency of the driving pulse signal is controlled in response to data showing the rotational speed of the fuel injection pump in such a way that the resonating phenomenon does not occur whereby the timer can be actuated smoothly without resonation of the timer.

Abstract: In a method for detecting the occurrence of a fault in a first sensor for producing first pulses of a repetitive time period related to a first condition to be detected or the occurrence of fault in a second sensor for producing second pulses indicative of a second condition to be detected at a ratio of one pulse to the production of N first pulses, the first pulses and the second pulses are used for monitoring each other and the detection of the occurrence of trouble in these sensors can be carried out with high reliability.