Mazda CX-5 Service & Repair Manual: Oil Control Valve (OCV)

Purpose, Function

• The OCV switches the oil passage to the hydraulic variable valve timing actuator to control the opening/closing period of the exhaust valve.

Construction

• The OCV is installed to the exhaust camshaft cap (No.1).

• The OCV consists of a spool valve which switches the engine oil passage and a plunger, coil, and return spring which operate the spool valve.

  

  
  

Operation

At retard

• The spool valve is moved to the retard side by the signal from the PCM and engine oil is lead to the retard oil passage of the exhaust camshaft.

  

  
  

At advance

• The spool valve is moved to the advance side by the signal from the PCM and engine oil is lead to the advance oil passage of the exhaust camshaft.

  

  
  

Middle point maintenance

• The spool valve is moved to the closed position of the oil passage to the exhaust camshaft by the signal from the PCM.

• The construction is designed to supply a small amount of oil to the advance oil passage even while the middle point is maintained, improving holding stability while at low oil pressure.

Fail-safe