Apparatus for and method of controlling internal combustion engines

In an apparatus for controlling an engine including a key switch connected to a voltage source, a starter for starting the engine, an intake manifold for supplying a mixed gas of sucked air and fuel and a throttle valve for limiting the rate of suction of air, a fuel supply control apparatus for the engine comprising:

• pressure detecting means provided at a suction passage downstream of said throttle valve for detecting the intake manifold pressure in the form of the absolute pressure;
• cranking detecting means for detecting whether said starter is in the ON condition or not;
• pressure change detecting means for detecting that the amount of change in pressure detected by said pressure detecting means is equal to or less than a first predetermined value during a predetermined period of time within the period from the time when said voltage source is turned on to the time when said cranking detecting means detects that the starter is on;
• memory means responsive to a detection signal from said pressure change detecting means for storing a pressure signal from said pressure detecting means as an atmospheric pressure detection value;
• and
• enrich control means which decides that said engine is in the enrich mode to allow the rate of fuel supply to be increased if a pressure signal of said pressure detecting means is equal to or larger than the difference between the atmospheric pressure detection value and a second predetermined value when said engine is in a driving mode other than the start mode.

In an apparatus for controlling an engine including a key switch connected to a voltage source, a starter for starting the engine, an intake manifold for supplying a mixed gas of sucked air and fuel and a throttle valve for limiting the rate of suction of air, an idling control apparatus for the engine comprising:

• bypass passage means for bypassing said throttle valve;
• first means for opening and closing said bypass passage means;
• pressure detecting means provided at a suction passage downstream of said bypass passage for detecting the intake manifold pressure in the absolute pressure;
• cranking detecting means for detecting whether said starter is in the ON condition or not;
• second means for storing a pressure signal of said pressure detecting means as an atmospheric pressure detection value if the amount of pressure change detected by said pressure detecting means is equal to or less than a first predetermined value during a predetermined period of time within the period from the time when said voltage source is turned on to the time when said cranking detecting means detects that said starter is on;
• and
• control means for controlling said first means to be opened or closed in accordance with the result of comparison between said atmospheric pressure detection value and a second predetermined value.

A method of controlling an engine comprising the steps of:

• detecting and storing the pressure in an intake manifold at a suction passage downstream of a throttle valve during a predetermined period within the period from the time when a voltage source is turned on to the time when a starter is on;
• obtaining the amount of change in said pressure;
• comparing said amount of change in said pressure with a predetermined value;
• reading said stored pressure as an atmospheric pressure detection value in the case where said amount of change is equal to or less than said predetermined value;
• and
• controlling said engine in accordance with said atmospheric pressure detection value.

A method of controlling a fuel supply for an engine comprising the steps of:

• detecting and storing the pressure in an intake manifold at a suction passage downstream of a throttle valve during a predetermined period within the period from the time when a voltage source is turned on to the time when a starter is on;
• obtaining the amount of change in said pressure;
• comparing said amount of change in said pressure with a first predetermined value;
• reading said stored pressure as an atmospheric pressure detection value if said amount of change is equal to or less than said first predetermined value;
• deciding whether said engine is in the start mode or not so as to obtain the difference between said atmospheric pressure detection value and a second predetermined value if said engine is not in the start mode;
• and
• controlling the rate of fuel supply if the pressure in said intake manifold is equal to or larger than said difference.

A method of controlling the idling of an engine comprising the steps of:

• providing a passage for bypassing a throttle valve;
• detecting and storing the pressure in an intake manifold at a suction passage downstream of said throttle valve during a predetermined period within the period from the time when a voltage source is turned on to the time when a starter is on;
• obtaining the amount of change in said pressure;
• comparing said amount of change in said pressure with a first predetermined value;
• reading said stored pressure as an atmospheric pressure detection value if said amount of change is equal to or less than said first predetermined value;
• comparing said atmospheric pressure detection value with a second predetermined value;
• and
• controlling said passage to be opened and closed in accordance with the result of such comparison.