Abstract: A gas ventilation system for an internal combustion engine is provided which includes a downstream intake pipe communicating with cylinders of the engine, an upstream intake pipe communicating with the downstream intake pipe through a throttle valve, and a gas ventilation pipe for recirculating a given gas to the engine. The system also has an inner hollow cylinder connected to the upstream intake pipe, disposed within the downstream intake pipe to define a gas passage between the periphery of the inner cylinder and an inner wall of the downstream intake pipe. The gas passage communicates with the gas ventilation pipe and serves as an isolating member for isolating flow of the gas entering the downstream intake pipe through the gas ventilation pipe from swirls produced by intake air flowing downstream of the throttle valve from the upstream intake pipe.

Abstract: An air-fuel ratio control device for an internal combustion engine controls an air-fuel ratio to the lean side rather than to a stoichiometric air-fuel ratio by the use of a factor determined in accordance with inlet pipe pressure and engine speed. A throttle opening degree sensor is provided to detect a degree of throttle opening, and on the basis of the degree of throttle opening, the factor determined in accordance with the inlet pipe pressure and the engine speed is corrected in a high load range of the engine. Since the output of the throttle opening degree sensor in the high load range of the engine is more accurate than the output of a pressure sensor for detecting the inlet pipe pressure, the air-fuel ratio can be controlled accurately in the high load range by correcting the factor in accordance with the degree of throttle opening.

Abstract: A fuel injection valve includes an injector body having a fuel injection hole and an adapter having a fuel collision surface, two air injection holes and two injected fuel paths. The fuel injected from the fuel injection hole flows in a slug-like pattern and collides with the fuel collision surface where the fuel is atomized a first time. Then, the fuel flows in a direction away from an axis of the adapter in a membrane-like pattern getting thinner in thickness to be finally broken to pieces, that is, to be atomized a second time. The air injected from the air injection holes collides with the membrane-like pattern of fuel to be atomized a third time before the fuel goes out of the injected fuel paths.

Abstract: A fuel injection valve for an internal combustion engine includes an injector body and an adapter. The injector body includes a single fuel injection hole and the adapter includes a concave portion defining a dead volume portion and a pillar extending from a bottom surface of the concave portion toward the fuel injection hole formed in the injector body. Fuel injected through the fuel injection hole into the dead volume portion collides with a top surface of the pillar to form a cone-like fuel flow pattern and a large portion of the fuel can directly flow into injected fuel paths formed in the adapted without attaching to and collecting on surfaces of various portions of the adapter. Thus, stable fuel injection from the injected fuel paths can be obtained.

Abstract: An internal combustion engine having two intake valves arranged in respective intake passages for each cylinder, wherein, a first intake passage is arranged to cause a swirl of intake air in the combustion chamber and a fuel injector is arranged in this intake passage, and a flow control valve is arranged in the second intake passage to close same when the engine load is low. An EGR passage is provided with an outlet in the second intake passage at a position between the second intake valve and the flow control valve, and the EGR gas is thus delivered to a volume enclosed in the second intake passage between the second intake valve and the flow control valve and remains there while these valves are closed. Then, when the second intake valve is open, the EGR gas slowly flows into the combustion chamber and floats toward and is collected at the upper region in the combustion chamber, while fuel flows smoothly into the combustion chamber, together with intake air, through the first intake passage.

Abstract: An internal combustion engine comprising three intake valves. The first intake valve and the second intake valve open at a crank angle near to the top dead center of the intake stroke. The third intake valve opens approximately at the center of the intake stroke. An air control valve is arranged in the second intake passage connected to the combustion chamber via the second intake valve. The air control valve is closed when the engine is operating under a partial load. A fuel injector is arranged in the third intake passage connected to the combustion chamber via the third intake valve. The injecting operation of the fuel injector is stopped during the intake stroke.

Abstract: An engine with three intake ports and three intake valves for each cylinder. The first intake port is a helical port. The remaining two intake ports have intake control valves, which open when the engine speed and the engine load are large and close when the engine speed and the engine are small. Air thus is introduced alternatively from the first port only or from all the ports. Fuel is injected in the third port between the corresponding intake valve and intake control valve.

Abstract: A shift indication apparatus having an engine rotation sensor, a throttle valve sensor, and a shift position sensor, a microcomputer having a ROM and RAM for storing data corresponding to the engine speed, throttle valve openings, and the shift positions therein, and an indicator for indicating preferable shift positions to be performed by a driver in which a torque data map and a fuel consumption rate data map have stored in the ROM for calculating various torque and fuel consumption rates so as to obtain preferable shift positions relating to optimum fuel consumption rate in accordance with said data detected. With this construction, it becomes possible for a driver to run his car in accordance with the indications of the shift operation on the indicator so as to enable the economical running of the car to be realized.

Abstract: An internal combustion engine provided with a first port of a helical shape and second port of a straight shape opened to the combustion chamber. The first port provides a swirl motion in the cylinder, while the second port is opened to the combustion chamber at a position near the spark electrodes located at the upper portion of the combustion chamber in the center thereof. An intake control valve selectively opens or closes the second intake port in accordance with operating conditions of the engine. A main injector is arranged in the second port downstream of the intake control valve. The injector is so controlled that it opens substantially during the intake stroke when the intake control valve is closed. The injector is controlled to inject at the period substantially not located in the intake stroke.

Abstract: A basic injection timing (InjO) is set, and an intermediate time (.DELTA.Inj) is set based on rotational speed of an engine and fuel injection pulse time in a fuel injector. A fuel injection starting timing (.theta.) is set according to the sum or difference of the basic injection timing and the intermediate time. As a result, mixture is introduced into a vortex controlled combustion chamber so that a rich mixture is distributed to the upper portion of the combustion chamber near the ignition plug to provide satisfactory stratified combustion.