Kia Niro: Intake And Exhaust System / Exhaust Heat Recovery System(EHRS) Description and operation

During cold start or in winter, the fuel efficiency can be improved by heating up the coolant with the exhaust gas heat discharged after combusting the engine. When the engine has been sufficiently warmed up, the valve on the passage of exhaust gas is opened to block the heat exchange of exhaust gas and coolant, thus to prevent overheating of coolant. The valve of the exhaust gas passage is opened and closed by the operation of wax actuator according to the temperature of coolant. To monitor the temperature of coolant, a separate water temperature sensor (WTS) is installed, and in the event of overheated coolant [over 120°C (248°F], the engine overheating warning lamp in the cluster is illuminated.

[Coolant Flow Chart]