Abstract: When differential pressure between fuel flowing into a fuel control valve and fuel flowing out of the valve reaches a predetermined value, the biasing force of a compressed coil spring is countered and a shaft in the valve moves to the fuel upstream side so that a valve member is seated to terminate communication between the fuel inlet passage and the fuel outlet passage. This maintains fuel pressure at the fuel inlet passage and at the fuel outlet passage at different levels so that the fuel supply system maintains a high fuel pressure in the fuel rail to suppress fuel vapor generation during engine stoppage while also yet still providing an appropriate fuel injection pressure during rapid deceleration of the vehicle.

Abstract: An antidissipation apparatus for evaporated fuel vapor for an internal combustion engine. A purge passage connects the intake manifold and the fuel tank. A canister is installed in the purge passage and adsorbs evaporated fuel vapor generated in the fuel tank. A purge pump is installed in the purge passage and delivers the adsorbed evaporated fuel vapor to the intake manifold. Since the purge pump is driven by at least a part of a fuel flow in the fuel passage, the purge pump can change its discharge amount of the adsorbed evaporated fuel vapor to the intake manifold according to an amount of the fuel flow in the fuel passage. Therefore, the evaporated fuel vapor which is adsorbed at the canister can be supplied (purged) to the intake manifold by the purge pump forcibly even if the engine is a lean-burn type which can not employ large negative pressure of the intake manifold.

Abstract: In a fuel pump control, until a rotational speed of an electrically-driven fuel pump rises to a predetermined speed, an electric current supplied to the fuel pump at an engine starting is increased higher than that normally supplied after engine starting thereby causing fast build-up of the fuel pressure. After the fuel pump reaches the predetermined speed, the electric current is decreased to a normal after-start current thereby suppressing a fuel pressure overshoot and resulting overrich mixture. Alternatively, a fuel pump speed is raised by the voltage control first at an engine starting operation, while switching the voltage control to the current control intermittently to detect the voltage applied to the fuel pump. When the detected voltage reaches a first predetermined voltage, the fuel pump speed is controlled exclusively by the current control.

Abstract: A pressure control valve includes a downstream pressure control valve disposed between a fuel pipe and a fuel rail. An opening-closing valve can be integrally formed with the downstream pressure control valve. A relief valve can be disposed to bypass the downstream pressure control valve. The downstream pressure control valve opens or closes the fuel passage leading to the fuel rail so that fuel pressure in the fuel rail is maintained at a predetermined value. When the engine is stopped, the fuel passage is closed to decrease leakage of fuel from the fuel injector. When the fuel pump is again operated, the by-pass relief valve is opened by the pressure of fuel in the fuel pipe. Thus, fuel is supplied from an upstream side to a downstream side and fuel pressure in the fuel rail is increased rapidly for engine re-start.

Abstract: A fuel filter having a filter element and fuel pump in a housing is disposed in a fuel tank. The filter element has a partition in contact with the fuel outlet side of the element. Fuel filtered by the element is divided into two stream passages, one of which is a return passage to the fuel tank and the other is a supply passage to fuel injectors of a common rail mounted on an engine. The amount of the stream returning to the tank is larger than the amount of the other stream so that a substantial amount of foreign particles in the fuel tank are carried by the returning stream and filtered. As a result, foreign particles may not so thickly accumulate on the filter portion in the supply passage.

Abstract: A fuel supply system for an engine having no fuel return pipe is disclosed. In steps target fuel is set according to an engine operating state. Thereafter, a target current value to be supplied to the motor of a fuel pump according to the target fuel pressure is obtained. In the succeeding step, an actual motor current is detected and, then, the target current value and the detcted current are compared. Thereafter, the supply current is controlled by feedback based upon the difference obtained by comparison between the target current value and the detected current value to eliminate the difference.

Abstract: A fuel pump is driven by a variable, constant current, control circuit. A pressure control valve disposed between the fuel pump and a fuel rail includes a downstream pressure control valve and a bypass valve bypassing the downstream pressure control valve. The downstream pressure control valve sets the fuel pressure in the fuel rail to a predetermined value by opening or closing a passage from a fuel pipe to the fuel rail. If the fuel pump discharge pressure is sufficiently increased, the bypass valve is opened when the upstream fuel pressure is larger than the downstream fuel pressure by at least a predetermined differential pressure. In this way, fuel is supplied to raise the fuel rail fuel pressure. Therefore, it is possible during other times to reduce the consumed electric power of the fuel pump and thus prolong its life.

Abstract: In a fuel supply system of an internal combustion engine, an actual fuel pressure Pf is measured by a differential pressure sensor and the actual fuel pressure Pf is averaged in a different degree to determine two kinds of values Pfs and Pft. The value Pfs is used to control the fuel pressure, while the value Pft is used to correct a pulse width. Then, a correction value Vfpci is determined according to the load applied to the engine and used in a feedback control to adjust a fuel discharge pressure of a fuel pump.

Abstract: According to the present invention, a fuel supply apparatus includes a fuel pump, a delivery pipe to distribute the fuel to each injector of the engine by receiving fuel supply by the fuel pump, a pressure sensor to detect the fuel pressure supplied to the delivery pipe, and a check valve disposed in the fuel discharge pipe of the fuel pump to prevent counterflow of the fuel from the delivery pipe. The amount of fuel discharged from the fuel pump is controlled to maintain the fuel pressure in the delivery pipe at a set value during fuel injection. At the stop of the engine, the amount of fuel discharged from the fuel pump is substantially reduced to zero, and the pressure of the fuel from the fuel pump is gradually reduced. After the pressure of the fuel discharged from the fuel pump reaches a predetermined value, the fuel pump stops. In this way the internal pressure of the delivery pipe is prevented from excessively rising without exterior parts such as a relief valve disposed outside of the fuel pump.

Abstract: A simple and compact fuel supply system which prevents generation of fuel vapor in a delivery pipe of an engine includes a check valve is disposed at a down stream portion of a fuel pressure relieving member or a fuel pressure regulator to seal the fuel delivery pipe when the engine stops so that the pressure in the delivery pipe increases as fuel vapor is generated and, consequently, generation of the fuel vapor is automatically suppressed. Transmission of a pressure wave from the delivery pipe caused while injectors are operating is prevented by the check valve so that harsh noise, which is otherwise caused by resonant vibration of fuel supply pipes and related members, is suppressed.

Abstract: A fuel supplying apparatus controls fuel pressure according to engine operating conditions to prevent blow-through of injected fuel into the exhaust system and hyper-vaporization of fuel. When the engine is being started and the fuel temperature is high, or when the engine has just started and the fuel temperature is high, a target fuel pressure is determined according to the fuel temperature. When a predetermined time has elapsed following the starting of the engine, or when the fuel temperature is not high (even if the predetermined time has not elapsed), it is determined whether fuel vapor is being purged from a canister into an intake pipe. The canister traps fuel vapor from a fuel tank. If the fuel purging is being performed, the apparatus determines whether the current engine operation is in a low-load region. If the fuel purging is being performed and the engine operation is in the low-load region, the apparatus computes a target fuel pressure according to the fuel purging conditions.

Abstract: A fuel supply system for an engine comprises a fuel pump for supplying fuel to fuel injectors, a pump controller which increases the fuel delivery flow rate from the fuel pump during hot restarting or high load running of the engine and a pressure regulator disposed in a fuel supply passage between the fuel pump and the injectors for adjusting the fuel supply pressure at which fuel is supplied to the injectors. The pressure regulator adjusts the fuel supply pressure according to an excess fuel flow rate of fuel returned to the fuel tank from the pressure regulator to a low-pressure side control pressure region over a first excess fuel flow rate range and to a high-pressure side control pressure region over a second excess fuel flow rate range.

Abstract: An apparatus for controlling intake air flow rate in an internal combustion engine comprises a throttle valve disposed in intake air passage for swing movement to change a flow rate of air to be supplied to combustion chambers of the engine, a stopper portion to which the throttle valve is abutted so as to stop swinging thereof in a full closed portion thereof, a spring for continually urging the throttle valve towards the full closed position, a control unit for determining a desired opening degree of the throttle valve in accordance with requirements on the engine, an actuator for generating a driving force for swinging the throttle valve to the desired opening degree in accordance with a command signal from the control unit, and geared mechanism for transmitting the driving force from the actuator to the throttle valve. The geared mechanism includes a pair of gears, each having a gear tooth portion. The gears are able to engage with each other exclusively at such gear tooth portions.

Abstract: The throttle valve position detecting device includes a metal fitting having a projection. This fitting is fixed to a throttle shaft, and a throttle position sensor is provided for detecting the position of a throttle valve by detecting the rotary position of the projection. The throttle position sensor includes a rotary shaft having the same rotary axis as the throttle shaft, a rotary element fixed to the rotary shaft and engaged with the projection of the metal fitting to be rotated thereby, a coil spring to press the rotary element against the projection, and a detecting circuit for electrically detecting the position of the throttle valve from rotation of the rotary shaft. The throttle shaft is supported relative to a throttle body through a bearing. Clearance between the throttle shaft and the bearing permits the throttle shaft to move while the automotive engine is idling.