System and method of thermal management for an engine

Patent metadata

Field	Value
Publication number	US-2016201548-A1
Application number	US-201514593414-A
Country	US
Kind code	A1
Filing date	Jan 9, 2015
Priority date	Jan 9, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A system and method of thermal management for an engine are provided. The system includes an engine, an electrical water pump, and a controller. The controller has a processor and tangible, non-transitory memory on which is recorded instructions. Executing the recorded instructions causes the processor to continuously monitor the temperature of the cylinder head and the temperature of the coolant. If the monitored temperatures of the cylinder head and the coolant are below predetermined thresholds, the processor executes a first control action, in which the pump remains off and the coolant remains stagnant. If either of the monitored temperatures of the cylinder head or coolant reaches the respective predetermined threshold, the controller initiates a second control action, which requires the controller to signal the pump to turn on and circulate coolant. The controller then determines the desired operating speed of the electrical water pump based on engine load.

First claim

1 . An engine thermal management system for a vehicle comprising:
an engine having an engine block and an engine cylinder head; an engine temperature sensor configured to monitor the temperature of the engine cylinder head; an electrical water pump configured to circulate a coolant through the engine; an engine water jacket having a coolant inlet and at least one coolant outlet, the engine water jacket configured to receive coolant from the electrical water pump at the coolant inlet; a first coolant temperature sensor configured to monitor the temperature of the coolant at the coolant inlet and a second temperature sensor configured to monitor the temperature of the coolant the at least one coolant outlet; a controller having a processor and tangible, non-transitory memory on which is recorded instructions, wherein executing the recorded instructions causes the processor to:
repeatedly monitor the temperature of the cylinder head via the engine temperature sensor and repeatedly monitor the temperature of the coolant via the second coolant temperature sensor;
compare the monitored temperature of the cylinder head to a predetermined cylinder head temperature threshold and compare the monitored temperature of the coolant to a predetermined coolant temperature threshold; and
execute one of a first control action and a second control action, such that the processor executes the first control action when the monitored temperature of the cylinder head is below the predetermined cylinder head temperature threshold and the monitored temperature of the coolant is below the predetermined coolant temperature threshold, and such that the processor executes the second control action when at least one of the temperature of the cylinder head exceeds the predetermined cylinder head temperature threshold and the temperature of the coolant exceeds the predetermined coolant temperature threshold, wherein:
the first control action includes repeatedly comparing the monitored temperature of the cylinder head to the predetermined cylinder head temperature threshold and repeatedly comparing the monitored temperature of the coolant to the predetermined coolant temperature threshold; and
the second control action includes:
signaling the electrical water pump to turn-on and circulate coolant;
determining a desired speed of the electrical water pump; and
adjusting the speed of the water pump to the desired speed.

2 . The engine thermal management system of claim 1 wherein determining the desired speed of the electrical water pump further includes:
determining an engine power of the engine;
determining an absolute heat rejection of the engine;
determining a desired coolant temperature delta between the coolant inlet and the coolant outlet;
determining a volumetric flow rate of the coolant; and
selecting a desired speed of the electrical water pump based on the determined volumetric flow rate of the coolant.

3 . The engine thermal management system of claim 2 wherein determining the engine power further includes:
determining an engine speed via the crankshaft sensor;
selecting a desired air mass per cylinder from a first look-up table written on the tangible non-transitory memory of the controller, wherein the first look-up table is a one-dimensional look-up table containing a set of desired air mass per cylinder values which correspond to a set of engine speed values;
determining maximum brake torque for the engine from a second look-up table written on the tangible non-transitory memory of the controller, wherein the second look-up table is a two-dimensional look-up table containing a set of maximum brake torque values for the engine based on the engine speed and the desired air mass per cylinder; and
calculating a determined engine power based on the determined maximum brake torque and the engine speed by multiplying the determined maximum bake torque by the determined engine speed.

4 . The engine thermal management system of claim 3 wherein determining the absolute heat rejection of the engine further includes:
determining a brake specific heat rejection for the engine from a third look-up table written on the tangible non-transitory memory of the controller, wherein the third look-up table is a two-dimensional look-up table containing a set of brake specific heat rejection values for the engine based on the engine speed and the desired air mass per cylinder; and
calculating a determined absolute heat rejection of the engine based on the determined brake specific heat rejection and the determined engine power by multiplying the determined brake specific heat rejection by the determined engine power.

5 . The engine thermal management system of claim 4 wherein determining the desired coolant temperature delta between the coolant inlet and the coolant outlet includes selecting a desired coolant temperature delta from a fourth look-up table, written on the tangible non-transitory memory of the controller, wherein the fourth look-up table is a two-dimensional look-up table containing a set of desired coolant temperature delta values for the engine based on the engine speed and the desired air mass per cylinder.

6 . The engine thermal management system of claim 5 wherein determining the volumetric flow rate of the coolant further includes:
multiplying the desired coolant temperature delta by a specific heat of the coolant to produce an evaluation element;
dividing the determined absolute heat rejection by the evaluation element to determine a mass flow rate of the coolant; and
dividing the mass flow rate of the coolant by a coolant density.

7 . The engine thermal management system of claim 6 wherein selecting a desired speed of the electrical water pump based on the determined volumetric flow rate of the coolant includes selecting a desired speed for the electrical water pump from a fifth look-up table written on the tangible non-transitory memory of the controller, wherein the fifth look-up table is a two-dimensional look-up table containing a set of desired speed values for the electrical water pump based on the volumetric flow rate of the coolant.

8 . The engine thermal management system of claim 1 wherein the predetermined coolant temperature threshold is the boiling point of the coolant.

9 . The engine thermal management system of claim 1 wherein the engine cylinder head is composed of a first material; and wherein the predetermined cylinder head temperature threshold is the deformation temperature of the first material.

10 . The engine thermal management system of claim 1 further including:
a plurality of flow control valves configured to receive coolant from at least one of the coolant pump and the engine water jacket;
a heater core configured to receive coolant from at least one of the plurality of flow control valves;
a transmission heat exchanger configured to receive coolant from at least one of the coolant pump and the engine water jacket via at least one of the plurality of flow control valves;
an engine oil heat exchanger configured to receive coolant from at least one of the coolant pump and the engine water jacket via at least one of the plurality of flow control valves;
a radiator configured to receive coolant from at least one of the plurality of flow control valves, the transmission heat exchanger, and the engine oil heat exchanger; and
wherein the controller is further configured to actuate the plurality of control valves to a selected actuation position and selectively distribute coolant to at least one of the heater core, the radiator, the transmission oil heat exchanger, and the engine oil heat exchanger based on the selected actuation position of the plurality of flow con

Assignees

• Gm Global Tech Operations Inc

Inventors

• Moscherosch Ben W
• Zahdeh Akram R

Classifications

• F01P2003/024

  Cooling cylinder heads · CPC title

• F01P2025/08

  Temperature · CPC title

• F01P7/162

  by cutting in and out of pumps · CPC title

• F01P7/164 Primary

  by varying pump speed · CPC title

• F01P2025/64

  Number of revolutions · CPC title