Auto Service Professional

DEC 2018

Magazine for the auto service professional

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Page 17 of 61

16 A S P D e c e m b e r 2 018 T e c h s H e l p i n g T e c h s ECOBOOST THERMOSTAT If you're not already familiar with the Ford Eco- Boost engine, the use of an electrically controlled thermostat is not the only way that the cooling system can be mapped or controlled for better overall efficiency. Ford uses an arrangement of control valves to control coolant flow on their 1.6L EcoBoost en- gines. e idea is to warm up the engine as fast as possible, reduce the internal engine operating friction and in turn lower emissions, and aid in heating the passenger compartment faster. is engine still uses a conventional wax pellet designed thermostat and thermo-syphon cooling to cool the turbo when the engine is shut off, but fine-tuning of the cooling system incor- porates a coolant shutoff solenoid valve, and a coolant bypass solenoid valve. ese valves are controlled by the PCM using a low side driver and allow the PCM to calibrate and tailor the coolant flow in four distinct operating modes, or "phases" as Ford calls them. With an ambient temperature of 60-75 de- grees Fahrenheit (16-24 degrees Celsius) or above (this temperature range can be customized by the engineers), both the coolant shutoff and the cool- ant bypass solenoid valves are closed. e coolant does not circulate in the engine or through any other cooling circuits. is lack of flow signifi- cantly reduces the warm-up time of the engine, and reduces start up emissions and lowers fuel economy during warm-up. With an ambient temperature of 60-75 de- grees F (16-24 degrees C) or below (again, this temperature range can be customized by the engineers), the coolant shutoff valve is opened; this allows coolant to circulate through the en- gine into the heater core, engine oil cooler, trans- mission oil cooler and around the bottom of the thermostat housing to warm the thermostat. When the coolant reaches 158 degrees F (70 degrees C) and the engine load is greater than 70% or the engine is revving greater than 4,000 rpm, the coolant bypass solenoid will open. is allows more coolant to flow from the engine to the thermostat housing, increasing the coolant The Ford EcoBoost features an electronically controlled thermostat.

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