IMRC (Intake Manifold Runner Control) System Description

• The IMRC (Intake Manifold Runner Control) system reduces fuel consumption and exhaust emission by producing the tumble air flow which makes A/F leaner when the engine is idling at low temperature.
• The tumble air flow is generated by opening/closing the IMRC valve located between the intake manifold and the cylinder head.
• The IMRC system consists of the following items.
  • IMRC valve (1)
  • IMRC valve actuator (2) (including in the IMRC valve motor and the IMRC valve position sensor)
    Fig 1: Identifying Intake Manifold Runner Control Component Location

    Courtesy of SUZUKI OF AMERICA CORP.
• The ECM drives the IMRC valve motor which is included in the IMRC valve actuator according to a vehicle speed, an engine speed, a coolant temperature and an accelerator pedal position.
• When the IMRC valve (1) driving conditions are met, the ECM sends "closing" signal to the IMRC valve motor. The IMRC valve motor closes the IMRC valve to create the tumble air flow (2).
• When the IMRC valve driving conditions are not met, The ECM sends "opening" signal to the IMRC valve motor. The IMRC valve motor opens the IMRC valve.
• The ECM detects an IMRC valve position by a non-contact type IMRC valve position sensor.

IMRC valve closing condition 

• Vehicle speed: Stop 
• Engine speed: Idling speed 
• Engine coolant temperature: Low 
• Accelerator position: Fully released 

Fig 2: Identifying IMRC Valve Close And IMRC Valve Open

Courtesy of SUZUKI OF AMERICA CORP.