Method and device for preventing engine knock during engine off-idle

A device for preventing knock in an engine having a combustion chamber and first and second airflow passages leading to the combustion chamber, comprising:

• a detector constructed and arranged to detect whether the engine is or is not in an off-idle state and to generate a detection signal corresponding to said detection of said off-idle state;
• a controller constructed and arranged to receive said detection signal from said detector and to generate a controlling signal corresponding to receipt of said detection signal;
• a solenoid valve constructed and arranged to receive said controlling signal from said controller, said controlling signal determining an ON/OFF state of said solenoid valve;
• an actuator connected to said solenoid valve, wherein said actuator operates in accordance with said ON/OFF state of said solenoid valve, said actuator having an open first end and a closed second end opposite said first end;
• a first throttle assembly comprising:
• a throttle shaft having an end slidably and rotatably disposed in said actuator via said open first end thereof;
• first and second rotatable members mounted on said throttle shaft;
• a second throttle assembly comprising a third rotatable member, wherein said second and third rotatable members are each constructed and arranged so as to be selectively engageable with each other, whereby a rotation of said second member causes said third member to rotate;
• a throttle body defining the first airflow passage;
• a throttle valve located in said throttle body and being constructed and arranged to control air flow to the combustion chamber via the first airflow passage, said second throttle being operationally connected to said throttle valve;
• and
• an idle speed actuator unit located in the second airflow passage and constructed and arranged to control air flow to the combustion chamber via the second airflow passage.

A method of preventing knock in an engine having a combustion chamber and first and second airflow passages leading to the combustion chamber, comprising:

• controlling air flow to the combustion chamber of the engine via the first air flow passage using a throttle valve;
• detecting an off-idle state of the engine;
• excluding said controlling step from controlling the throttle valve when said detecting step detects said off-idle state;
• and
• controlling air flow to said combustion chamber of the engine via the second air flow passage.