The Effect of Fuel Properties on Low and High Temperature Heat Release and Resulting Performance of an HCCI Engine

(1)

The Effect of Fuel Properties on Low and High Temperature Heat Release and Resulting

Performance of an HCCI Engine

著者（英） Gen Shibata, Koji Oyama, Tomonori Urushihara, Tsuyoshi Nakano

journal or

publication title

第2回技術セミナー : 国際セミナー「エンジンシステムの燃焼過程」

page range 1‑27

year 2004‑05‑28

権利（英） Research Center for Energy Conversion System of Doshisha University

URL http://doi.org/10.14988/re.2017.0000015729

(2)

2004-01-0553

Gen Shibata and Koji Oyama

Central Technical Research Laboratory Nippon Oil Corporation

Tomonori Urushihara and Tsuyoshi Nakano

Nissan Research Center Nissan Motor Co., Ltd

The Effect of Fuel Properties on Low and High Temperature Heat Release and

Resulting Performance of an HCCI Engine

What Influences HCCI Operation?

• Engine side

– Intake Air Conditions

• Temperature and Pressure

• Fuel Side

– Fuel Properties

• Chemical Component ignition properties

• Fuel Vaporization Characteristics

(3)

Experimental Schematic

O2 Sensor Laminar Air

Flow Meter

OUT AC

Dynamometer IN

20C 60%

Humidity Air

Rotary Encoder HCCI Engine

Supercharger Pressure Transducers

for 4 Cylinders Fuel Injection and Spark

Ignition Controller for 4 Cylinders

Pressure Data T

T,P

THC, NOx, CO, CO2

Fuel Cooler

Fuel Consumption Meter

Data Output T,P

Engine Specification

Engine type 4 cylinder MPI

Compression ratio 15

Bore 86mm

Stroke 86mm

Displacement 1998cc

Exhaust valve open 53°CA BBDC

Exhaust valve close 7°CA ATDC

Intake valve open 1°CA ATDC

Intake valve close 19°CA ABDC

(4)

The Boiling Point-RON map of the Fuel Components

0 40 80 120 160

0 20 40 60 80 100 120 140

RON

B o il in g P o in t ° C

n-Pentane

iso-Pentane

Isoprene

2Methylpentane 4Methyl1pentene

Cyclohexane Cyclohexene

n-Hexane

n-Heptane 2.2.4 Trimethylpentane

(iso-Octane) C9 iso-Paraffin

m-Xylene

Area A

Area B Area C

Area D Area E

RON 70 RON 80 RON 92

Description of Test Fuels

RON70 RON80 RON92 Regular Gas

70.0 80.0 92.0 90.0

68.5 68.0 67.8 76.0

15.0 6.0 4.5 3.5

Density g/cm3 0.6965 0.7076 0.724 0.7306

Reid Vapour Pressure kPa 45.0 43.5 44.0 73.5

Distillation °C 0% 42.0 45.5 44.0 29.0

10% 59.0 61.5 60.5 45.5

30% 68.0 69.5 69.0 62.0

50% 80.5 81.5 81.5 83.5

70% 97.5 98.5 99.0 112.5

90% 129.0 129.0 128.5 139.0

95% 134.0 133.5 133.0 150.5

EP 143.0 138.5 141.5 171.5

vol%

11.5 0 0 -

8.5 15.7 12.7 -

0 4.3 7.3 -

1.5 6.9 12.4 -

18.5 13.1 7.6 -

5.3 2.0 0 -

14.7 18.0 0 -

0 0 20.0 -

6.0 4.0 1.6 -

14.0 16.0 18.4 -

1.4 4.7 7.9 -

18.6 15.3 12.1 -

m-Xylene C9 iso-paraffin Area A

Isoprene

n-Heptane 2.2.4Trimethylpentane Octane Number RON

Cetane Number Octane Number MON

Fuel Composition

iso-Pentane n-Pentane

Area D

Area E

2Methylpentane n-Hexane Cyclohexane Cyclohexene Area B

Area C

4Methyl1pentene

(5)

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

(6)

HCCI Engine Performance Test (1)

• Engine Speed Test

Fuel: RON70

Engine Speed: 1200, 1400, 1600rpm Intake Manifold Pressure: +41.3kPa(gage) Intake Manifold Temp: 55-60℃

Air/Fuel Ratio: 40.5 constant Water & Oil Temp: 80 ℃

• Engine Load Test

The Effect of Engine Speed on RHR

-10 10 30 50 70

-40 -20 0 20 40

Crank Angle deg

R H R J / C A d e g

Fuel: RON70 A/F: 40.5 Intake Manifold Temp.: 55-69°C Press.: 41.3kPa gage

LTHR*

HTHR*

1200rpm

1400rpm

1600rpm

LTHR*--- Low Temperature Heat Release HTHR*---High Temperature Heat Release

Crank Angle Data

(7)

The Effect of Engine Speed on RHR

-100 0 100 200 300 400

-4 -2 0 2 4 6 8

Time ms

J / m s

Fuel: RON70 A/F: 40.5 Intake Manifold Temp.: 55-69°C Press.: 41.3kPa gage

1200rpm 1400rpm

1600rpm Time Data

HCCI Engine Performance Test (2)

• Engine Speed Test

• Engine Load Test

Fuel: Regular Gasoline (Japan Market)

Engine Speed: 1200rpm

Intake Manifold Pressure: +41.3kPa(gage) Intake Manifold Temp: 62-63 ℃

Air/Fuel Ratio: 28, 29, and 30

Water & Oil Temp: 80℃

(8)

The air-fuel Ratio was changed by holding the air quantity constant and changing the injected fuel quantity.

A/F Change = Load Change

HCCI Engine Performance Test (2)

• Engine Speed Test

• Engine Load Test

Fuel: Regular Gasoline (Japan Market)

Engine Speed: 1200rpm

Intake Manifold Pressure: +41.3kPa(gage) Intake Manifold Temp: 62-63 ℃

Air/Fuel Ratio: 28, 29, and 30 Water & Oil Temp: 80℃

HCCI Engine Performance

Test (2)

(9)

The Effect of Engine Load on RHR

-10 40 90

-40 -20 0 20 40

Crank Angle deg

R H R J / C A d e g

Fuel: Regular

Engine Speed: 1200rpm Intake Manifold Temp.: 62-63°C Press.: 41.3kPa gage

A/F=28 A/F=29

A/F=30

No Change

The Effect of Engine Load on RHR

0 500 1000 1500 2000

-40 -20 0 20 40

Crank Angle deg

A ve . G as T e m p. K

Fuel: Regular

Engine Speed: 1200rpm Intake Manifold

Temp.: 62-63°C Press.: 41.3kPa gage

A/F=28 A/F=29

A/F=30

Gas Temperature Histories

of HTHR are changed

HTHR start

(10)

Overview

• Engine Speed affects HCCI combustion, which also differs according to load condition

(Engine operating range is restricted)

Fuel volatility and composition also affect the HCCI combustion to the same degree as engine speed and load changes (⇒Octane Number Test)

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

(11)

Pre-Ignition Vaporized Fraction for In-Cylinder Hydrocarbons

High Speed In-cylinder Gas Sampling Schematic Gas Sampling Valve Timing Chart

<SAE 952521>

Pre-Ignition Vaporized Fraction for In-Cylinder Hydrocarbons

0 10 20 30 40 50 60 70 80 90 100

0 50 100 150 200

Hydrocarbon Component Boiling Temperature ℃

Vaporization Fraction in the Cylinder %

Engine Oil & Water Temperature 40 ℃

Engine Oil & Water Temperature 80℃

Sampling Period:

59-32BTDC

(12)

<SAE 952521>

Pre-Ignition Vaporized Fraction for In-Cylinder Hydrocarbons

0 10 20 30 40 50 60 70 80 90 100

0 50 100 150 200

Hydrocarbon Component Boiling Temperature ℃

Vaporization Fraction in the Cylinder %

2 Methylbutane

M-Xylene

Sampling Period:

59-32BTDC

• RON distribution against distillation is important

• RON70, RON80 and RON92 fuels were selected to keep the same distillation and same RON distribution against distillation

Pre-Ignition Vaporized Fraction for In-Cylinder Hydrocarbons

•The mole fraction distribution in the vaporized fuel changes with crank angle and depends on the fuel even for a warmed up engine

•If the RON distribution against distillation is different,

the vaporized fuel RON history during combustion changes

(13)

Engine Speed-Torque Map

RON 92

RON 80

RON 70

Knock Limit Misfire Limit

Engine Speed rpm

E n g in e T o rq u e N m

Knocking Intensity*

650kPa/deg CA 430kPa/deg CA 200kPa/deg CA

1000rpm

Regular

*Knocking Intensity is defined as the 400cycle average of the Maximum rate of pressure increase.

Octane Number Test

• Test Conditions

Fuel: RON70, RON80, RON92,

Regular

Engine Speed: 1000rpm

Intake Manifold Pressure: +26.7kPa(gage) Intake Manifold Temp: 47-50℃

Knocking Intensity: 430kPa/deg CA

Water & Oil Temp: 80 ℃

(14)

RHR data of Octane Number Test

-10 20 50 80

-40 -20 0 20 40

Crank Angle deg

R H R J /C A d e g

Engine Speed: 1000rpm Intake Manifold

Temp.: 47-50°C Press.: 26.7kPa gage

RHR data of Octane Number Test

28.7 30

33.8 42.5

Air/Fuel Ratio

41.40 40.08

38.25 36.11

% Thermal Efficiency

654.7 586.2

452.5 373.4

kPa IMEP

47.8 50.2

47.1 47.0

°C Intake Air Temperature

12.6 10.3

6.3 2.2

Crank Angle of 50% Burned ATDC

6.0 6.5

6.5 8.0

Crank Angle BTDC

925.1 935.9

968.5 989.9

°K Temperature Star

t

608.6 528.9

407.3 332.8

J Heat Value High

Temperature Heat Release

16.5 17.5

18.0 18.5

853.7 832.3

855.9 859.3

t

2.8 11.2

16.7 23.8

J Heat Value Low

RON92 Regular

RON80 RON70

Unit

(15)

RHR data of Octane Number Test

28.7 30

33.8 42.5

Air/Fuel Ratio

41.40 40.08

38.25 36.11

654.7 586.2

452.5 373.4

kPa IMEP

47.8 50.2

47.1 47.0

12.6 10.3

6.3 2.2

6.0 6.5

6.5 8.0

925.1 935.9

968.5 989.9

t

608.6 528.9

407.3 332.8

16.5 17.5

18.0 18.5

853.7 832.3

855.9 859.3

t

2.8 11.2

16.7 23.8

RON80 RON70

Unit

RON70 fuel has larger LTHR than RON92

RHR data of Octane Number Test

28.7 30

33.8 42.5

Air/Fuel Ratio

41.40 40.08

38.25 36.11

654.7 586.2

452.5 373.4

kPa IMEP

47.8 50.2

47.1 47.0

12.6 10.3

6.3 2.2

6.0 6.5

6.5 8.0

925.1 935.9

968.5 989.9

t

608.6 528.9

407.3 332.8

16.5 17.5

18.0 18.5

853.7 832.3

855.9 859.3

t

2.8 11.2

16.7 23.8

RON80 RON70

Unit

RON70 fuel has a margin for high speed operation!

(16)

Temperature History of Octane Number Test

-0.2 0 0.2 0.4 0.6 0.8 1

0 500 1000 1500 2000

Ave. Gas Temperature K

J/(ms IMEP)

Engine Speed: 1000rpm Intake Manifold Temp.: 47-50°C Press.: 26.7kPa gage

6.0 6.5

6.5 8.0

925.1 935.9

968.5 989.9

°K Temperature Start

High Temperature Heat Release

RON80 RON70

Unit

LTHR

HTHR

RON70

Regular RON80

RON92

Temperature History of Octane Number Test

-0.2 0 0.2 0.4 0.6 0.8 1

0 500 1000 1500 2000

Ave. Gas Temperature K

J/(ms IMEP)

Engine Speed: 1000rpm Intake Manifold Temp.: 47-50°C Press.: 26.7kPa gage

6.0 6.5

6.5 8.0

925.1 935.9

968.5 989.9

°K Temperature Start

High Temperature Heat Release

RON80 RON70

Unit

RON70

Regular RON80

RON92

(17)

Low Temperature Heat Release and Engine Performance at Constant Knocking Intensity

@ same knocking intensity…

0 5 10 15 20 25

RON92 Regular RON80 RON70

Low Temperature Heat Release J

0 200 400 600 800

RON92 Regular RON80 RON70

IMEP kPa

Engine Speed: 1000rpm Intake Manifold Temp.: 47-50°C Press.: 26.7kPa gage

η＝41.4%

A/F=28.7% η＝40.1%

A/F=30.0%

η＝38.3%

A/F=33.8% η＝36.1%

A/F=42.5%

The Relation Between the Starting Temperature of High Temperature

Heat Release and CA50

0 5 10 15

900 920 940 960 980 1000

Starting Temperature of High Temp. Heat Release K

C A 50 A T D C de g

Engine Speed: 1000rpm Intake Manifold

Temp.: 47-50°C Press.: 26.7kPa gage

RON70 Regular

RON80

RON92

(18)

The Relation between fuel Types and Engine

Performances

High Good

Narrow Rich Side

Large Small LTHR

Fuel

Low Poor

Wide Lean Side

Small Large LTHR

Fuel

Thermal Efficiency Anti-Knocking

Performance Engine Speed

Range Air Fuel Ratio

Range Engine

Torque Fuel Type

Large LTHR fuel Easy Knock, High Speed, Low Torque Fuel

Small LTHR fuel Difficult knock, low Speed, High Torque Fuel

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

(19)

N-Heptane and Toluene Test

• Test Conditions

Fuel: Base, MC7, MC10

Engine Speed: 900rpm

Intake Manifold Pressure: +50.7kPa(gage) Intake Manifold Temp: 53-54 ℃

IMEP: 470kPa

Water & Oil Temp: 80 ℃

Description of the Three Test Fuels for N-Heptane and

Toluene Test

BASE MC7 MC10

Octane Number RON 87.5 83.5 90

MON 68 64.5 66.5

Density g/cm3 0.7292 0.7264 0.7384

Reid Vapour Pressure kPa 38.0 36.5 36.0

J/g 43487 43556 43260

Distillation °C 0% 51.5 51.5 52.0

10% 67.0 69.0 69.0

30% 73.5 75.5 76.0

50% 82.5 85.0 85.5

70% 96.5 97.0 98.5

90% 114.5 113.0 114.5

95% 128.5 127.0 125.5

EP 143.5 142.5 144.0

Remarks - BASE+6.5%

n-Heptane

BASE+6.5%

Toluene Lower Heating Value

(20)

Heat Release Data of BASE, MC7 and MC10

-20 0 20 40 60 80 100 120

-40 -30 -20 -10 0 10 20 30 40

Crank Angle deg

RHR J/CA deg

Engine Speed: 900rpm IMEP: 470kPa Intake Manifold

Temp.: 53-54°C Press.: 50.7kPa

MC7

BASE

MC7

LTHR and HTHR Data of N- Heptane and Toluene Test

41.5 41.7

41.5 Air/Fuel Ratio (Exhaust O2 Sensor)

37.03 38.48

39.97

470.0 473.6

468.4 kPa

IMEP

54.0 54.0

52.8

6.6 6.6

6.7 kW

Engine Power

70.2 70.2

71.1 Nm

Engine Torque

7 8.5

9.5 BTDC Crank Angle

Start

462.8 442.6

416.0 J

Heat Value High Temperature

Heat Release

16.5 16.5

18.5 BTDC

Crank Angle Start

13.1 14.5

23.0 J

Heat Value Low Temperature

Heat Release

MC10 BASE

MC7 Unit

(21)

LTHR and HTHR Data of N- Heptane and Toluene Test

41.5 41.7

37.03 38.48

39.97

470.0 473.6

468.4 kPa

IMEP

54.0 54.0

52.8

6.6 6.6

6.7 kW

Engine Power

70.2 70.2

71.1 Nm

Engine Torque

7 8.5

Start

462.8 442.6

416.0 J

Heat Release

16.5 16.5

18.5 BTDC

13.1 14.5

23.0 J

Heat Release

MC10 BASE

MC7 Unit

• Chemistry changes the start crank angle of LTHR

• The temperature range of LTHR is dependent on the chemical components

LTHR and HTHR Data of N- Heptane and Toluene Test

41.5 41.7

37.03 38.48

39.97

470.0 473.6

468.4 kPa

IMEP

54.0 54.0

52.8

6.6 6.6

6.7 kW

Engine Power

70.2 70.2

71.1 Nm

Engine Torque

7 8.5

Start

462.8 442.6

416.0 J

Heat Release

16.5 16.5

18.5 BTDC

13.1 14.5

23.0 J

Heat Release

MC10 BASE

MC7 Unit

Heating Value of LTHR → MC10≒0.9×BASE MC10 is a mixture of 93.5% BASE and 6.5% Toluene

Toluene does not exhibit LTHR

(22)

LTHR and HTHR Data of N- Heptane and Toluene Test

41.5 41.7

37.03 38.48

39.97

470.0 473.6

468.4 kPa

IMEP

54.0 54.0

52.8

6.6 6.6

6.7 kW

Engine Power

70.2 70.2

71.1 Nm

Engine Torque

7 8.5

Start

462.8 442.6

416.0 J

Heat Release

16.5 16.5

18.5 BTDC

13.1 14.5

23.0 J

Heat Release

MC10 BASE

MC7 Unit

The LTHR of MC10 is initiated by the chemical components of BASE

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

(23)

Octane Index

OI=RON-K*(RON-MON)

(K depends on engine operating conditions) SAE 2001-01-3584

In this test… K=-0.365

RON had a much stronger influence on the octane number test results than MON

-2.00 0.00 2.00 4.00 6.00 8.00 10.00

60 65 70 75 80 85 90 95

RON

CA10 ATDC deg CA10=4.022E-1*RON-2.8863E1 (R^2=0.9818)

-2.00 0.00 2.00 4.00 6.00 8.00 10.00

65.0 75.0 85.0 95.0 105.0

OI (K=-0.365)

CA10 ATDC deg

CA10=3.074E-1*OI-2.2443E1 (R^2=0.997)

Topics in this Presentation

• HCCI Engine Performance Test

– Engine Speed Test – Engine Load Test

• Octane Number Test

• N-Heptane and Toluene Test

• Correlation of HCCI Operation to Octane Sensitivity

• What are RON and MON?

(24)

RON-MON Distribution Map for General Chemicals in Gasoline

60 70 80 90 100 110 120

60 80 100 120

RON

M O N

Paraffins

Aromatics Naphthenes and Olefins

The Change of the LTHR Grade on RON and MON

Conditions

• HCCI combustion is a “slow and mild knocking phenomenon of SI engines

<Assumption>

LTHR Magnitude Grade 0 No LTHR

･･･

Grade 4 Large LTHR

Grade 0 Grade 0

Toluene

iso-Octane

Inlet Air Temp. 142C Inlet Air Temp. 52C

MON Condition RON Condition

(25)

The Change of the LTHR Grade on RON and MON

Conditions

• HCCI combustion is a “slow and mild knocking phenomenon of SI engines

<Assumption>

LTHR Magnitude Grade 0 No LTHR

･･･

Grade 4 Large LTHR

Toluene

iso-Octane

Inlet Air Temp. 142C Inlet Air Temp. 52C

MON Condition RON Condition

What are RON and MON?

I’m 100!

RON

The size of faces refers to the size of LTHR Mr. Iso-Octane Ms. Toluene

RON 100 RON

120

_{I’m 125.}

(26)

What are RON and MON?

Inlet air heating made me smaller, but I’m

still 100!

MON

The size of faces refers to the size of LTHR

I became

103, because of

your diet!

MON 100 MON

120 Ms. Toluene Mr. Iso-Octane

What are RON and MON?

• From the point of view of iso-octane, toluene approaches iso-octane behavior with inlet air heating

• The difference in grade for the MON condition is 2-levels in contrast to 3-levels for the RON condition

RON is larger than MON for aromatic fuels, and the

same reasoning may be applied to olefins and

naphthenes

(27)

Conclusions

1. The reaction time period from LTHR start to HTHR finish is constant for a given fuel and independent of engine speed. As the engine speed increases, the period in crank angles is simply elongated. This effectively restricts the engine speed range where HCCI combustion is practical.

Conclusions

2. A fuel with a large heating value of LTHR is an

“Easy Knock, High Speed & Low Torque” fuel, and a fuel with a small heating value of LTHR is a “Difficult Knock, Low Speed &High Torque”

fuel. These tendencies were consistent for the

fuels with the same distillation and same RON

distribution against distillation .

(28)

Conclusions

3. A small change in chemical composition can change the HCCI combustion characteristics, including the amount and the phasing of LTHR that significantly affect the HTHR. To develop and test HCCI engines, knowing the effects of fuel characteristics on HCCI combustion is very important.