Abstract: An apparatus for controlling ignition timing in an internal combustion engine determines the amount of adjustment of ignition timing for preventing knocking with reference to the engine operating state. The amount of adjustment of the ignition timing carried out upon the detection of knocking is varied depending on the engine speed. Specifically, it is made large in the low speed region where the interval between successive firings is relatively long, thus increasing the speed with which knocking can be prevented and enhancing the protection of the engine from damage in this operating region. Also, rapid acceleration and other transient engine operating states are detected and a transient state adjustment is calculated separately of the adjustment amount for knocking prevention. The transient state adjustment is added to the knocking prevention adjustment and the result is used for retarding the ignition timing, whereby knocking can be effectively prevented during rapid acceleration.

Abstract: A variable air induction control system for an internal combustion engine. The engine intake passage is divided into a long and small diameter main passage and a short and large diameter auxiliary passage. The auxiliary passage is provided with a valve which is opened and closed to adjust the air flow rate. The system is arranged such that, in accordance with the cylinder pressure, the intake air passes through the main intake passage during low speed engine operation and through both the main and auxiliary passages during high speed engine operation, whereby the air induction efficiency (charging efficiency) is enhanced and the engine output increased. As knocking is more likely to occur when the air induction efficiency is high, the opening/closing of the valve is controlled depending on whether or not knocking occurs. Moreover, it may be arranged such that when knocking does occur, it is first coped with by retarding the ignition and if knocking cannot be eliminated in this way, the air intake is adjusted.

Abstract: A method of and an apparatus for controlling ignition timing in an internal combustion engine. When the ignition timing has been retarded for preventing knocking and the engine operation thereafter moves into a region of operation where knocking control is unnecessary with the retardation of the ignition timing still in effect, the ignition timing is slightly advanced once per predetermined number of firings. Since the ignition timing is gradually restored, engine output hunting is prevented. The advancement of the ignition timing is determined whether or not a prescribed wait period has passed. The period varies depending on an engine speed.

Abstract: A method of and an apparatus for controlling ignition timing in an internal combustion engine, which determines the ignition timing on the basis of the engine speed and load state, discriminates whether or not knocking has occurred on the basis of the output of a knocking detection circuit, retards the so-determined ignition timing by a predetermined amount when knocking occurs, and advances the ignition timing by a predetermined amount after knocking has been avoided. The maximum amount of retardation and advancement carried out upon occurrence of knocking is varied depending on one or more engine operating conditions, enabling the ignition timing to be controlled to near MBT and the engine output to be the maximum possible. The said engine operating condition or conditions include an engine speed in the case of compensation in the direction of ignition retardation and include an engine speed and a load state in the case of compensation in the direction of ignition advance.

Abstract: A method of and an apparatus for controlling boost pressure in a turbocharged internal combustion engine. A turbine disposed in the engine exhaust passage is driven by exhaust gas and in turn drives a compressor disposed in the engine air intake passage, thus boosts the engine combustion chamber by delivering pressurized air thereto. The boost pressure is reduced when the actual ignition timing becomes more retarded than a reference ignition timing. The reference ignition timing is varied in proportion to an engine speed and/or an intake air pressure. Since the decision whether or not to reduce the boost pressure is based on the ignition timing actually being applied to the engine, no risk of damage to the engine arises and unnecessary reduction of engine output can be reliably prevented, enabling the engine to operate with optimum performance.

Abstract: Creep rupture strength of austenitic heat resisting steel containing chromium and nickel is improved by adding to the steel small amounts of niobium, a niobium-tantalum or a niobium-tantalum-titanium mixture, and maintaining a Nb/C ratio of less than 3.5.