Internal combustion engine coolant flow control

Patent metadata

Field	Value
Publication number	US-11365672-B2
Application number	US-201916707290-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Dec 9, 2019
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

An internal combustion engine includes an engine block, a combustion cylinder including a cylinder wall, engine oil and engine coolant. Control of the internal combustion engine includes estimating the cylinder wall temperature in a temperature state estimator, comparing the estimated cylinder wall temperature to a predetermined temperature threshold, and circulating the engine coolant in the engine when the estimated cylinder wall temperature exceeds the predetermined temperature threshold.

First claim

What is claimed is:

1. A method for controlling an internal combustion engine including an engine block, a combustion cylinder including a cylinder wall, engine oil and a coolant pump for controllably circulating engine coolant, comprising:
estimating, while the engine is operating and the coolant pump is disabled to establish static coolant flow conditions, the cylinder wall temperature with a thermal state model including a temperature state estimator, the temperature state estimator comprising a plurality of temperature state equations based upon modeled heat transfers within the internal combustion engine, the plurality of temperature state equations comprising:
a cylinder wall temperature state equation comprising a combustion gas to cylinder wall heat transfer term based upon a fraction of an adiabatic temperature increase within the cylinder contributing to a combustion gas temperature increase within the cylinder wherein the cylinder wall temperature state equation comprises:
m w eng c pw eng {dot over (T)} w eng =−{dot over (Q)} w,c eng −{dot over (Q)} w,o eoh +{dot over (Q)} g,w eng

wherein m w eng comprises the mass of the cylinder wall,
c pw eng comprises the specific heat of the cylinder wall,
{dot over (T)} w eng comprises cylinder wall temperature,
{dot over (Q)} w,c eng comprises heat transfer from the cylinder wall to the engine coolant,
{dot over (Q)} w,o eoh comprises heat transfer from the cylinder wall to the engine oil, and
{dot over (Q)} g,w eng comprises heat transfer from combustion gas to the cylinder wall determined in accordance with the following relationship:

π
⁢
B
⁢

k
g

4

⁢
a
⁢

Re
b

⁡

(

T

g
,
corr

-

T
w

e
⁢
n
⁢
g

)

wherein B comprises the cylinder bore diameter,
k g comprises the thermal conductivity of the cylinder wall,
Re comprises the Reynolds number,
a and b comprise engine specific parameters, and
T g,corr comprises a combustion gas temperature correction term based in part upon the fraction of the adiabatic temperature increase within the cylinder contributing to the combustion gas temperature increase within the cylinder; and

an engine coolant out temperature state equation based upon static coolant flow conditions;

comparing the estimated cylinder wall temperature to a predetermined temperature threshold; and
enabling the coolant pump for circulating the engine coolant in the engine when the estimated cylinder wall temperature exceeds the predetermined temperature threshold.

2. The method of claim 1 , wherein the engine coolant out temperature state equation assuming no coolant flow comprises:
m c eng c pc eng {dot over (T)} c,out eng ={dot over (Q)} w,c eng −{dot over (Q)} c,b eng

wherein m c eng comprises the mass of the engine coolant surrounding the cylinder wall,
C pc eng comprises the specific heat of the engine coolant,
{dot over (T)} c,out eng comprises engine coolant out temperature change,
{dot over (Q)} w,c eng comprises heat transfer from the cylinder wall to the engine coolant, and
{dot over (Q)} c,b eng comprises heat transfer from the engine coolant to the engine block.

3. The method of claim 1 , wherein the plurality of temperature state equations further comprises:
an engine block temperature state equation
m b eng c pb eng {dot over (T)} b eng ={dot over (Q)} c,b eng +{dot over (Q)} o,b eoh −{dot over (Q)} b,a eng

wherein m b eng comprises the mass of the engine block,
c pb eng comprises the specific heat of the engine block,
{dot over (T)} b eng comprises engine block temperature change,
{dot over (Q)} c,b eng comprises heat transfer from the engine coolant to the engine block,
{dot over (Q)} o,b eoh comprises heat transfer from the engine oil to the engine block, and
{dot over (Q)} b,a eng comprises heat transfer from the engine block to ambient air.

4. The method of claim 1 , wherein the plurality of temperature state equations further comprises:
an engine oil temperature dynamics relationship
m o eoh c po eng {dot over (T)} o eoh ={dot over (Q)} w,o eoh +{dot over (Q)} c,o eoh +{dot over (Q)} b,o eoh+S fric

wherein m o eoh comprises the mass of the engine oil,
c po eng comprises the specific heat of the engine oil,
{dot over (T)} o eoh comprises engine oil temperature change,
{dot over (Q)} w,o eoh comprises heat transfer from cylinder wall to engine oil,
{dot over (Q)} c,o eng comprises heat transfer from engine coolant to engine oil,
{dot over (Q)} b,o eoh comprises heat transfer from engine block to engine oil, and
S fric comprises heat from mechanical friction imparted to the engine oil.

5. A method for controlling an internal combustion engine including an engine block, a combustion cylinder including a cylinder wall, engine oil and a coolant pump for controllably circulating engine coolant, comprising:
modeling the internal combustion engine as a plurality of heat transfers;
defining a plurality of temperature state equations based upon the plurality of heat transfers;
measuring a plurality of temperature state variables;
implementing, within a controller while the engine is operating and the coolant pump is disabled to establish static coolant flow conditions, a thermal state model providing an estimated cylinder wall temperature, the thermal state model comprising the plurality of temperature state equations including receiving the plurality of temperature state variables, the plurality of temperature state equations comprising:
a cylinder wall temperature state equation comprising a combustion gas to cylinder wall heat transfer term based upon a fraction of an adiabatic temperature increase within the cylinder contributing to a combustion gas temperature increase within the cylinder wherein the cylinder wall temperature state equation comprises:
m w eng c pw eng {dot over (T)} w eng =−{dot over (Q)} w,c eng −{dot over (Q)} w,o eoh +{dot over (Q)} g,w eng

wherein m w eng comprises the mass of the cylinder wall,
c pw eng comprises the specific heat of the cylinder wall,
{dot over (T)} w eng comprises cylinder wall temperature,
{dot over (Q)} w,c eng comprises heat transfer from the cylinder wall to the engine coolant,
{dot over (Q)} w,o eoh comprises heat transfer from the cylinder wall to an engine oil, and
{dot over (Q)} g,w eng comprises heat transfer from combustion gas to the cylinder wall determined in accordance with the foll

Assignees

• Gm Global Tech Operations Llc

Inventors

• Chang Insu
• Sun Min
• Edwards David E

Classifications

• F01P2025/32

  Engine outcoming fluid temperature · CPC title

• F01P2025/31

  Cylinder temperature · CPC title

• F01M5/002

  Cooling · CPC title

• F01P7/16 Primary

  by thermostatic control · CPC title

• F02F1/02

  having cooling means (cylinder heads F02F1/26) · CPC title