Post on 10-Jan-2022
2004-01-0933
U.S. Environmental Protection AgencyRuonan Sun • Rick Thomas • Charles L. Gray, Jr.
Clean Automotive Technology…Clean Automotive Technology…Innovation that WorksInnovation that Works
An HCCI EnginePower Plant for a Hybrid Vehicle
www.epa.gov/otaq/technology
22004-01-0933
Benefits of HCCI Engines
High thermal efficiency Low NOx and PM emissions Potentially low incremental cost
32004-01-0933
Challenges of HCCI
Controlling Ignition and CombustionExpending Useful Operating Range Managing Transient OperationReducing HC and CO emissionsFinding Real World Applications
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Program Objectives
Explore operating range and performance of a multi-cylinder HCCI engineStudy transient operation capabilities
Determine if an HCCI engine can be a suitable power plant for a hydraulic hybrid drivetrain
(or any series hybrid)
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Laboratory Setup of Test Engine
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Control Strategy
Primary parameters were adjusted by the engine controller to maintain a single target combustion parameter.
Primary parameters included the fueling rate, boost level, EGR, intake charge and coolant temperatures.
Target combustion parameter was the maximum rate of pressure rise.
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Control Strategy (continued)
Primary parameters mapped to yield/keep: Best efficiencyStable operation(COV of IMEP < 3%) Combustion noise not too high(MRPR ~ 6 bar/deg)Low NOx emissions (NOx < 0.2 g/kWh)
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Steady State – Combustion StabilityHCCI Closed Loop Response (Cylinder 1)
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000
Cycle Number
Max
. Rat
e of
Pre
ssur
e Ri
se
(bar
/deg
)
MRPRDesired MRPR
HCCI Closed Loop Response (Cylinder 2)
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000
Cycle Number
Max
. Rat
e of
Pre
ssur
e R
ise
(bar
/deg
)
MRPR
Desired MRPR
HCCI Closed Loop Response (Cylinder 3)
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000
Cycle Number
Max
. Rat
e of
Pre
ssur
e R
ise
(bar
/deg
)
MRPR
Desired MRPR
HCCI Closed Loop Response (Cylinder 4)
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000
Cycle Number
Max
. Rat
e of
Pre
ssur
e R
ise
(bar
/deg
)
MRPR
Desired MRPR
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Steady State – Intake Temperature
406080
100
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
Intake Temperature (deg C)
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20
2040
40 60
60
80
80
100
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
Intake Pressure (kPa, Gage)
Steady State – Intake Pressure
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10152025
30
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
EGR (%)
Steady State – EGR Rate
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Steady State – Combustion Phasing
34
56
78
8
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
Max Rate of Pressure Rise (bar/deg)
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Steady State – Engine Efficiency
510152025
30
35
00
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
Brake Thermal Efficiency (%)
Hybrid Vehicle Operation
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Steady State – NOx Emissions
0.1
0.1
0.20.2
0.2
00
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP (b
ar)
Engine Speed (rpm)
NOx (g/kWhr)(0.15 g/hph)
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Steady State – HC Emissions
1020
20
304050
50
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BME
P (b
ar)
Engine Speed (rpm)
HC (g/kWhr)
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Steady State – CO Emissions
20
20
406080 100
100
0
2
4
6
8
10
500 1000 1500 2000 2500 3000 3500 4000 4500
BM
EP
(bar
)
Engine Speed (rpm)
CO (g/kWhr)
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Transient Operation
0
5
10
15
20
25
30
35
40
500 1500 2500 3500Engine Speed (RPM)
Shaf
t Pow
er (k
W)
Ramp down in 1 secondRamp up in 5 seconds
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Conventional Vehicle Power Demand (kW)
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
DrivePower
Drive Power (kW)
0 50 100 150 200 250 300 (seconds)
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-10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
DrivePower Full Hybrid
Series Hydraulic Hybrid VehiclePower Demand (kW)
Drive Power (kW)
0 50 100 150 200 250 300 (seconds)
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Conclusions1. An HCCI engine with mostly current
production components can operate over a wide range of conditions with low NOx emissions and good thermal efficiencies.
2. The engine can make transitions along a preset power curve.
3. The engine shows potential as a power plant for a hybrid vehicle.
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Future TasksDeveloping a better matched boost system to improve power density and efficiency
Improving the control logic for better transient response
Reducing engine out HC and CO and testing aftertreatment devices
Starting directly in HCCI mode when engine is cold
Testing the engine in a hybrid vehicle
2004-01-0933
U.S. Environmental Protection AgencyRuonan Sun • Rick Thomas • Charles L. Gray, Jr.
Clean Automotive Technology…Clean Automotive Technology…Innovation that WorksInnovation that Works
An HCCI EnginePower Plant for a Hybrid Vehicle
www.epa.gov/otaq/technology