Warm up control system for an internal combustion engine

An electronic warm up control system for an automotive vehicle for controlling an idle air flowing through an auxiliary air intake passage bypassing a throttle chamber of a primary air intake passage, and a spark ignition timing and a spark advance corresponding to the engine operating condition, which control system including an idle air control valve means operable in response to a control signal fed from a controller,

• wherein said control system comprising:
• an engine temperature sensor for determining the engine temperature and generating an engine temperature signal indicative of the determined engine temperature;
• a crank angle sensor for detecting crank standard angle and crank refrence angle and generating a crank standard angle signal and reference crank angle signal;
• a controller receiving said engine temperature signal, crank standard angle signal and the reference crank angle signal and determining engine speed, said controller determining a target engine speed and a maximum engine warm up rate corresponding to the engine temperature signal by looking up tables respectively storing the target engine speed and the maximum engine warm up rate in relation to the engine temperature and feedback controlling the engine speed based on the difference between the determined actual engine speed and the target engine speed and controlling the spark advance and spark ignition timing in relation to the maximum engine warm up rate so that the engine warm up efficiency is increased with a suitable engine operating condition corresponding to the engine condition.

In a warm up control system for an internal combustion engine for effective start up characteristics of the engine, a method for controlling the engine operation comprising:

• determining an engine temperature and generating a first signal indicative of the determined engine temperature;
• detecting a crank revolution angle and generating a second signal per each predetermined crank revolution angle;
• determining a target engine speed based on the engine temperature represented by said first signal;
• determining a required maximum engine warm up rate based on the engine temperature represented by said first signal;
• feedback controlling the engine speed by controlling an idle air flow rate corresponding to a difference between the target engine speed and the actual engine speed represented by the second signal in order to reduce the difference to zero;
• and
• controlling a spark ignition timing and a spark advance so that the engine warm up rate is kept at the determined maximum warm up rate