B-MAX 2012 – Engine Cooling – 1.0L EcoBoost (74kW/100PS)/1.0L EcoBoost (90kW/120PS)/1.0L EcoBoost (103kW/140PS) (YY) – Engine Cooling – System Operation and Component Description – Description and Operation

Engine Cooling - 1.0L EcoBoost (74kW/100PS)/1.0L EcoBoost (90kW/120PS)/1.0L EcoBoost (103kW/140PS) (YY) - Engine Cooling - System Operation and Component DescriptionB-MAX 2012.75 (01/2012-)
Description and Operation

System Diagram

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Item
Description
1
Reservoir
2
Heat exchanger
3
Oil cooler
4
Thermostat housing – small/large coolant circuit and bypass valve
5
Cylinder head – exhaust side
6
Short block thermostat
7
Cylinder block and cylinder head – intake side
8
Mechanical coolant pump
9
Electric coolant pump
10
Turbocharger
11
Radiator

System Operation

Cooling system function

The cooling system is controlled in 3 phases.

Phase 1

When the engine is cold, the small/large coolant circuit thermostat and the short block thermostat are closed.

The mechanical coolant pump delivers the coolant only to the exhaust-side part of the cylinder head. In this phase, the coolant in the coolant jacket around the cylinder and in the intake-side part of the cylinder head remains motionless.

Below a coolant temperature of approximately 50°C and below an engine speed of approximately 3000 rpm, only the exhaust-side part of the cylinder head is cooled.

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Item
Description
1
Reservoir
2
Heat exchanger
3
Oil cooler
4
Casing – Thermostat – Small/large coolant circuit and bypass valve
5
Cylinder head – exhaust side
6
Short block thermostat
7
Cylinder block and cylinder head – intake side
8
Mechanical coolant pump
9
Electric coolant pump
10
Turbocharger
11
Radiator

The coolant flows from the part of the cylinder head on the exhaust side into the thermostat housing in the small/large coolant circuit and bypass valve and, from there, via the heater core to the oil cooler and then back to the coolant pump.

In addition, part of the coolant flows from the short block through the electrical coolant pump and, from there, on past the exhaust gas turbocharger to the coolant expansion tank and then back to the coolant pump.

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Below a coolant temperature of approximately 50°C and below an engine speed of approximately 3000 rpm, the small/large coolant circuit thermostat and the bypass valve are closed.

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Item
Description
1
Coolant flow from oil cooler
2
Coolant flow to heat exchanger
3
Small/large coolant circuit thermostat
4
Bypass valve
5
Coolant flow to mechanical coolant pump
6
Excessive coolant flow from exhaust-side part of the cylinder head

If the engine speed exceeds approximately 3000 rpm, the bypass valve opens. The now increased coolant pressure from the engine opens the bypass valve so that the increase pressure can escape directly to the intake side of the coolant pump.

Phase 2

The short block thermostat opens at a coolant temperature of 50 °C and is completely open at 85 °C.

As with a conventional system, this opens the small coolant circuit.

The coolant pump now also delivers the coolant to the cooling jacket around the cylinder, washes around it and enters the entire cylinder head via the bore holes.

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Item
Description
1
Reservoir
2
Heat exchanger
3
Oil cooler
4
Thermostat housing – small/large coolant circuit and bypass valve
5
Cylinder head – exhaust side
6
Short block thermostat
7
Cylinder block and cylinder head – intake side
8
Mechanical coolant pump
9
Electric coolant pump
10
Turbocharger
11
Radiator

Phase 3

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Item
Description
3
Small/large coolant circuit thermostat
4
Bypass valve
7
Coolant flow to the radiator

The small/large coolant circuit thermostat opens at a coolant temperature of 92 °C and is completely open at 106 °C. At the same time, the bypass valve thermostat closes. This ensures that the entire coolant flow, regardless of the coolant pressure, is always routed via the radiator.

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Item
Description
1
Reservoir
2
Heat exchanger
3
Oil cooler
4
Casing – Thermostat – Small/large coolant circuit and bypass valve
5
Cylinder head – exhaust side
6
Short block thermostat
7
Cylinder block and cylinder head – intake side
8
Mechanical coolant pump
9
Electric coolant pump
10
Turbocharger
11
Radiator

Component Description

Electric coolant pump

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With this engine, in addition to the usual mechanical coolant pump, an electric coolant pump is installed in the coolant circuit.

The pump is secured onto the cooling fan housing via a retaining device.

The coolant pump is only activated whenever the coolant temperatures exceeds a critical value. This can occur in particular if the engine has been operated at a high load for a long time and is then parked immediately afterwards. For example, after a long motorway journey at high speed, with subsequent parking at a service station. This can lead to an excessive build-up of heat around the engine after the engine has been switched off.

The null (powertrain control module) activates the electric coolant pump to prevent any damage due to this build-up of heat.

It can therefore be the case that the electrical coolant pump continues to run for a certain period of time.

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Item
Description
1
Reservoir
2
Heat exchanger
3
Oil cooler
4
Thermostat housing – small/large coolant circuit and bypass valve
5
Cylinder head – exhaust side
6
Short block thermostat
7
Cylinder block and cylinder head – intake side
8
Mechanical coolant pump
9
Electric coolant pump
10
Turbocharger
11
Radiator

With the electrical coolant pump activated, the coolant flows through the exhaust gas turbocharger to the coolant expansion tank and from there through the mechanical coolant pump in the short block to the electrical coolant pump.

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