Abstract: A control system in an automobile has a controller to provide an air-to-fuel ratio leaner than an ideally combustible air-to-fuel ratio when a lean control range of engine operating conditions is detected, and a controller to increase an air flow rate so as to enrich a fuel mixture when an engine operating condition is transitional to the lean control range. The control system conducts sequentially the lean control and the enrich control according to transitional patterns to the lean control range.

Abstract: An internal combustion engine is provided with a fuel injection valve. The fuel injection valve is actuated so that fuel injected therefrom reaches the combustion chamber in the latter half of the intake stroke, thereby accomplishing stratified charge. The timing at which blow-back of intake gas occurs is detected and the timing for terminating fuel injection is advanced as the timing at which blow-back of intake gas occurs becomes earlier.

Abstract: An intake system for a rotary piston engine having a plurality of engine sections, each engine section being separated by an intermediate housing. In the intake system, there are provided communicating passages for communicating the engine sections so that intake air can be transferred between working chambers formed in the engine sections in accordance with a difference in rotor phase between the engine sections. The communicating passage is located so as to be closed after an intake port is closed in each engine section and positioned so that there remains a larger amount of intake air in each of the working chambers than the minimum amount of intake air required for ensuring idling rotation speed under idling engine operating condition when the communicating passage is closed. This intake system makes it possible to obtain a rotary piston engine which can remarkably reduce pumping loss and desirably control the amount of intake air in accordance with an engine operating condition.

Abstract: An intake system for an internal combustion engine comprises a first valve provided to open and close an intake passage leading to each combustion chamber, a bypass passage for introducing intake air into each combustion chamber bypassing the first valve, and a second valve provided to open and close each of the bypass passages. The first valves are operated to close the respective intake passages in a light load range and to open the same in a heavy load range. The second valve is operated to close the bypass passage in the middle of each intake stroke. The first valves are controlled so that the opening of the intake passages is increased as the engine load increases after exceeding a predetermined value, and the second valve is controlled to delay the time the bypass passage is closed with increase in the engine load so that the time the bypass passage is opened overlaps with the time the intake valve is opened when the engine load reaches the predetermined value.

Abstract: An internal combustion engine is provided with a separately formed intake passage for each cylinder. Each intake passage is provided with a fuel injection valve. The fuel injection valve is controlled to inject fuel in the latter half of the intake stroke of the corresponding cylinder. The amount of fuel injected from the fuel injection valve is increased upon acceleration of the engine by an amount which is separately determined for each cylinder and is generally reduced in the order of the firing order.

Abstract: An engine intake system includes a combustion chamber, a first intake port opening to the combustion chamber, and a second intake port opening to the combustion chamber. A shut-off valve is provided for blocking intake gas flow to the combustion chamber through the second intake port in a first engine operating region wherein engine load is relatively small, and allowing the intake gas to flow to the combustion chamber through the second intake port in a second engine operating region wherein the engine load is relatively large. A first valve actuating mechanism is provided for opening the first intake valve at a first timing, and a second valve actuating mechanism is provided for opening the second intake valve at a second timing.

Abstract: A dual induction type intake system for an internal combustion engine has a primary intake passageway for light load operation of the engine and a secondary intake passageway for heavy load operation of the engine. The downstream side open end of each intake passageway opens toward the intake port of the cylinder of the engine. The secondary intake passageway is provided with a controllable valve therein. The load on the engine is detected and the controllable valve is opened when the load on the engine is heavier than a predetermined value so that the intake gas is introduced into the combustion chamber through both the primary and secondary intake passageways, while otherwise the controllable valve is closed so that the intake gas is introduced into the combustion chamber only through the primary intake passageway.