System Description

The multi-way control valve changes the paths to heater, oil cooler, and radiator according to engine coolant temperature and driving conditions.

When coolant temperature is low, the paths to heater, oil cooler, and radiator are closed and coolant is circulated only inside the engine to accelerate engine warm-up.

When coolant temperature is high, the paths to heater, oil cooler, and radiator are opened and coolant is refrigerated. This raises the coolant temperature and oil temperature rapidly and improves the fuel economy by reducing friction among parts.

Operation 

When the ignition switch is OFF, the valve is fully opened to accelerate bleeding the coolant channels.

When receiving a blower fan ON signal and/or an A/C ON signal, ECM opens the flow path to the heater even when coolant temperature is low.

Courtesy of NISSAN NORTH AMERICA, INC.

Courtesy of NISSAN NORTH AMERICA, INC.

A: Closes all flow paths , , and and circulates coolant only inside the engine.

B: Opens the flow path to Heater and circulates coolant to Heater.

C: Opens the flow path to oil cooler and circulates coolant to Heater and oil cooler.

D: Opens the flow path to radiator and circulates coolant to Heater, oil cooler, and radiator.

E: Opens all the flow paths , , and .

The high coolant temperature control is performed by opening/closing the flow path to the radiator to raise the engine oil temperature even when the coolant temperature is high. When engine load is high, the high coolant temperature control is not performed because of the knocking control.

When detecting a malfunction in multi-way control valve, ECM fully opens the valve to secure cooling paths.