Abstract: A flow rate control system for controlling the idling rpm of an engine of a vehicle to a predetermined level in accordance with the temperature of cooling water or outdoor air, so as to eliminate hunting occurring in the flow rate of air supplied to the engine at engine startup the system includes a first valve seat, adapted to come into and out of engagement with a first valve body of a flow rate control valve assembly, and an annular protrusion located on a portion of an inner peripheral surface on an inlet side of the first valve seat. A conical surface portion is located downstream of the annular protrusion on an outlet side of the inner peripheral surface and divergingly tapers in a direction toward a downstream side of the first valve seat.

Abstract: Automotive engine idle speed control device meters the flow rate of air supplied to the engine bypassing an intake pipe thereof during engine idle operation to thereby control the engine idle speed. An actuating vacuum is produced in accordance with an electrical signal and acts on a diaphragm fixed to a valve movable with the diaphragm to meter the bypass air flow. To cancel any external force acting on the valve, adjusting means is provided to control the vacuum on the diaphragm independently of the electrical signal to displace the diaphragm in a direction opposite to the direction of action of the external force on the valve.

Abstract: An idle speed control device has an electromagnetic driving portion and a flow rate controlling portion disposed in a bypass passage formed in a throttle chamber such as to bypass a throttle valve. The flow rate controlling portion has a body defining a passage for the fluid to be controlled, a seal formed in an intermediate portion of the passage, a first valve driven by the plunger of the electromagnetic driving portion through a rod such as to be brought into and out of contact with the seat, a sleeve disposed in the body, and a second valve connected through a rod to the downstream side of the first valve such as to produce a vacuum force which acts in the opposite direction to the vacuum force produced on the first valve thereby to absorb any fluctuation in the intake pressure in cooperation with the first valve, the second valve being loosely received by the sleeve.

Abstract: A proportional type electromagnetic valve comprises a flow rate control valve secured to a movable core which moves a stroke in proportion to the input current, and a valve seat portion cooperative with the flow rate control valve to control the flow rate. In addition to a bias spring providing for urging the flow rate control valve toward the valve seat portion, a second spring is disposed on the movable core for urging the flow rate control valve to release it from the valve seat portion. The resultant force of the two springs makes the stroke of the flow rate control valve proportional to the input current.

Abstract: A solenoid valve for controlling a flow of fluid, the valve includes valve body having a path for fluid, a valve seat disposed in the path, a first cylindrical bore and a second cylindrical bore opposite thereto with respect to the valve seat. A valve guide is fitted into the second cylindrical bore and a rod of a valve member is inserted into the valve guide. An annular projection of an electromagnetic driver is inserted into the second cylindrical bore and an output shaft extending through the annular projection is engaged with the valve member.

Abstract: A current-stroke proportional type solenoid valve has a movable plunger disposed around the inner peripheral wall of a bobbin with a coil therearound, a stator core disposed face to face with the movable plunger and forming the magnetic circuit, a bias spring for always biasing the movable plunger in one direction and the stroke of the movable plunger being determined by magnitude of the current flowing through the coil. In the solenoid valve, the output rod is axially supported by a first lubricant resin and the movable plunger also by a second lubricant resin.

Abstract: An exhaust gas recirculation control system for controlling the amount of exhaust gas subjected to recirculation to the air inlet depending on the amount of inlet air of an internal combustion engine. This system comprises a control valve disposed in an exhaust gas recirculation passage, for controlling the amount of exhaust gas recirculation, an orifice disposed in the recirculation passage, for creating a negative pressure upstream of the control valve, and a solenoid valve for generating a pressure which controls the control valve.

Abstract: A car exhaust gas purification device controlling circuit wherein a deviation between an output of an exhaust gas sensor and a set value is converted into a time-width signal and a proportional electromagnetic valve is controlled by an integrated output of the time-width signal to control the air-fuel ratio around a theoretical air-fuel ratio, whereby an offset of air-fuel ratio due to hysteresis of such as the proportional electromagnetic valve used for controlling the air-fuel ratio is eliminated.

Abstract: An air-fuel ratio control apparatus for use in a motor vehicle having an internal combustion engine provided with a carburetor including a main fuel supply system and a low speed fuel supply system for supplying fuel to the engine. The apparatus includes an electromagnetic valve for controlling the volume of air flowing through the air bleed of the main fuel supply system, an electromagnetic valve for controlling the volume of air flowing through the air bleed of the low speed fuel supply system, an O.sub.2 sensor for detecting the concentration of O.sub.2 in exhaust emissions, and a control circuit for producing as an output a control signal in accordance with a signal from the O.sub.2 sensor. The two electromagnetic valves are controlled by the same signal from the control circuit.

Abstract: An apparatus for purifying an exhaust gas on the basis of a single three-functional catalyst capable of oxidizing hydrocarbons and carbon monoxide, and simultaneously reducing nitrogen oxides, where a fuel-controlling means is provided for dividing driving conditions into an accelerating stage as zone I, a steady running stage as zone II, and a slowing-down and idling stage as zone III, and controlling an air-fuel mixture to be fed from a carburetor to a reducing state of the three-functional catalyst in zone I, a three-functional state in zone II, and an oxidizing state in zone III.

Abstract: The output of an oxygen concentration detector monitoring the conditions of exhaust gases from an internal-combustion engine is not a linear function of the concentration but varies widely. When feeding this output back to control the air-fuel ratio of the mixture being fed to the engine, the feed back system having the small time constant (small delay time in operation) becomes unstable due to the nonlinear output of the oxygen concentration detector. In order to stabilize the operation of the system the output of the oxygen concentration detector is input to compensating circuit which outputs the voltage being proportioned to the oxygen concentration of the exhaust gas and the output is used as the feedback signal.

Abstract: An apparatus which comprises a detector for detecting the density of one component (oxygen, for example) of exhaust gases from an internal combustion engine for regulating the ratio of air to fuel based on the detected value of the component in such a manner that the air-fuel ratio can be made approximate to the theoretical air-fuel ratio. The apparatus further comprises a first comparator having a hysteresis range and a second comparator having no hysteresis range for detecting the output of the detector for detecting the density of one component of exhaust gases, in order that variations in the characteristics of the detector or changes in its characteristics with time can be compensated for.

Abstract: A control system for controlling the ignition of fuel in an internal combustion engine with differential ignition timing comprising a first and a second ignition plug disposed in each combustion chamber of the engine, and a first and a second ignition system associated with the first and second ignition plugs respectively. A pulse delay circuit is provided in the second ignition system and the time constant thereof is varied depending on the operating condition of the engine for varying the rate of delay of the ignition timing of the second ignition plug in the second ignition system relative to the ignition timing of the first ignition plug in the first ignition system. This delay time is reduced in an operating range requiring a high engine output so that the demand for purificaton of exhaust gases and the demand for desired operating performance of the engine which are contradictory to each other can be satisfied.

Abstract: A dilute air-fuel mixture operation as a method for purifying exhaust gas is effective for reducing simultaneously carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in the engine exhaust. However, such operation reduces engine power remarkably. Though a reciprocating internal combustion engine having first and second spark plugs has been introduced to compensate this disadvantage, it has in turn brought about the problem that there is a tendency of increasing quantities of nitrogen oxides. While an increase of the interval between the firing of the two plugs may control an increase of nitrogen oxides, this results in a reduction of engine power. A most effective method of exhaust purification is to control an ignition system such that the interval between the firing of two plugs is made short only when high engine power is required, and the firing interval is made comparatively long in the normal operation of the engine.