System and method for avoiding compressor surge during cylinder deactivation of a diesel engine

Patent metadata

Field	Value
Publication number	US-11454181-B2
Application number	US-202017000416-A
Country	US
Kind code	B2
Filing date	Aug 24, 2020
Priority date	Feb 26, 2018
Publication date	Sep 27, 2022
Grant date	Sep 27, 2022

Abstract

A system and method for improving the functioning of a turbocharged diesel engine equipped with a cylinder deactivation system includes detecting when the turbocharged diesel engine is at risk of compressor surge, and then delaying the implementation of the cylinder deactivation. The delay may be a set period of time, or it may be determined by performing a set of instructions effective for estimating changes in intake manifold pressures over time if cylinders are deactivated, and then comparing the intake manifold pressure estimates to acceptable intake manifold pressure information. A formula for performing the required estimates is provided.

First claim

The invention claimed is:

1. A method for improving the functioning of a turbocharged diesel engine equipped with a cylinder deactivation system, the method comprising detecting when the turbocharged diesel engine is at risk of compressor surge, and then delaying part or all of the cylinder deactivation until risk of compressor surge is not indicated;
wherein said detecting is accomplished by calculating estimates of changes in intake manifold pressure (IMP) for specific cylinder deactivation (CDA) conditions, and then comparing those estimates to the compressor surge line for the engine to determine whether deactivation of one or more cylinders will avoid compressor surge;
wherein said estimates are calculated by a set of steps comprising:
a) measuring or estimating the mass flow rate of fresh air leaving the compressor of a turbocharged diesel engine having n cylinders;
b) measuring or estimating the intake manifold pressure of said engine;
c) providing information indicating the displacement of the engine, the future number of active cylinders, and the volumetric efficiency of the engine;
d) using the mass flow rate information, the intake manifold pressure information, the engine displacement information, and the volumetric efficiency information to estimate changes in intake manifold pressures over time if some or all engine cylinders are deactivated;
e) comparing the intake manifold pressure estimates to acceptable intake manifold pressure information to determine whether deactivating cylinders would be expected to produce an unacceptable intake manifold pressure at any relevant time subsequent to a cylinder deactivation; and
f) if the comparison of step (e) indicates that one or more cylinders could be deactivated without being expected to produce an unacceptable intake manifold pressure at any relevant time, deactivating the greatest number of cylinders that may be deactivated without producing an unacceptable intake manifold pressure.

2. A method according to claim 1 wherein the method further includes moving into cylinder deactivation as quickly as possible while avoiding compressor surge.

3. A method according to claim 1 wherein said estimates are calculated by a set of steps comprising:
a) measuring, or calculating from known parameters, the mass flow rate of fresh air leaving the compressor of the engine;
b) measuring the intake manifold pressure of the engine;
c) measuring the engine speed of the engine;
d) measuring the exhaust gas recirculation fraction of the engine; and
e) measuring the intake manifold temperature of the engine;
f) providing information indicating the displacement of the engine, the future number of active cylinders, the volumetric efficiency of the engine, and the volume of the intake tract;
g) using the mass flow rate information, the intake manifold pressure information, the engine speed information, the exhaust gas recirculation fraction information, the intake manifold temperature information, the engine displacement information, the volumetric efficiency information, and the intake tract volume information to estimate changes in intake manifold pressures over time if some or all engine cylinders are deactivated;
h) comparing the intake manifold pressure estimates to acceptable intake manifold pressure information to determine whether deactivating cylinders would be expected to produce an unacceptable intake manifold pressure at any relevant time subsequent to a cylinder deactivation; and
i) if the comparison of step (h) indicates that one or more cylinders could be deactivated without being expected to produce an unacceptable intake manifold pressure at any relevant time, deactivating the greatest number of cylinders that may be deactivated without producing an unacceptable intake manifold pressure;
wherein each of said estimates of the change in expected intake manifold pressure over time is determined using the formula:

P
i

+
1

=

m
in

+

P
i

⁢

V
intake

RT
⁢

⁢
Δ
⁢

⁢
t

V
disp

⁢

num
cyc

⁢

η
vol

⁢

RPM
⁡

(

1
-

EGR
frac

)

120
⁢

⁢
RT

+

V
intake

RT
⁢

⁢
Δ
⁢

⁢
T

where:

Symbol
Description

m in
Mass flow rate of fresh air leaving the compressor

P i
Intake Manifold Pressure at instant i

V disp
Displacement of the Engine

num cyl
Future Number of Active Cylinders

η vol
Volumetric Efficiency

RPM
Engine Speed

Assignees

• Purdue Research Foundation
• Eaton Intelligent Power Ltd

Inventors

• Taylor Alexander H
• Odstrcil Troy E
• Shaver Gregory M
• Mccarthy Jr James E

Classifications

• F02D2200/0414

  Air temperature · CPC title

• F02D13/06

  Cutting-out cylinders · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02D2200/0406

  Intake manifold pressure · CPC title

• F02B2039/166

  the fluid pressure in the pump or exhaust drive being limited · CPC title