Partially Premixed Combustion, PPC – Why all diesel engines ...

Partially Premixed Combustion, PPC
– Why all diesel engines should be run on
gasoline
Bengt Johansson
Lund University

First a little statement:
Dual fuel is not needed!
And 100.000 diesel cars per year are
filled up with the wrong fuel in UK. Can
we expect an average US car owner to
put two correct fuels in two tanks?

But I still think a single
fuel is enough…

Gross Indicated Efficiency [%]
Scania diesel engine running on gasoline
Group 3, 1300 [rpm]
60
55
!
η i =57% 147 g/kWh (@43 MJ/kg heating value)
50
45
40
FR47333CVX
FR47334CVX
FR47336CVX
35
30
25
20
0 2 4 6 8 10 12 14
Gross IMEP [bar]
4

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

+ Clean with 3-way
Catalyst
- Poor low & part load
efficiency
Background
Combustion concepts
+ High efficiency
- Emissions of NO x and
soot
Spark Ignition (SI)
engine (Gasoline, Otto)
Compression Ignition
(CI) engine (Diesel)
+ High efficiency
Homogeneous Charge -Combustion control
+ Ultra low NO Compression Ignition
x -Power density
(HCCI)
Spark Assisted
Compression Ignition
(SACI)
Gasoline HCCI
+ Injection controlled
- Less emissions
advantage
Partially premixed
combustion (PPC)
Diesel HCCI

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

Partially Premixed Combustion, PPC
HC [ppm]
NOx [ppm]
Spridare 8x0.12x90 & 8x0.12x150, Iso-oktan, CR-tryck 750 bar, Duration 0,6 ms = 3.6 CAD
6000
1200
HCCI
PCCI
CI
5000
PPC
1000
4000
800
3000
600
2000
400
1000
200
-180 -160 -140 -120 -100 -80 -60 -40 -20
SOI [ATDC]
Def: region between truly homogeneous combustion, HCCI,
and diffusion controlled combustion, diesel
SAE 2004-01-2990
9

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

2006-01-3412
Characterization of Partially Premixed
Combustion (PPC)
Christof Noehre, Magnus Andersson, Bengt Johansson and
Anders Hultqvist
PPC with Diesel Fuel!

Experimental setup
Specifications of single cylinder engine:
Displacement Volume 1951 cm³
Swirl Ratio (standard) 1.7
Swirl Ratio (if modified) 2.9
Fuel
Swedish MK 1 Diesel, CN51
Injector holes 8
Injector hole diameter 0.18 mm
Spray umbrella angle 120
Compression ratios
A=12.4:1; B=14.3:1; C=17.1:1
SAE 2006-01-3412
12

Emissions at 8 bar IMEP
Load
Abs. Inlet Pressure
Engine Speed
Swirl Ratio 1.7
Compression Ratio
Inlet temp without
EGR
Inlet temp max
EGR
8 bar IMEP
2.5 bar
1090 rpm
12.4:1 (Low)
25 C
55 C
SAE 2006-01-3412
13

1
3
4
5
Injection virtually
finished before start of
combustion
14

Why is PPC not possible at highest
compression ratio?
- One reason: insufficient ignition delay
15

Effect of EGR and compression ratio at 8 bar IMEP
EGR sweep and compression ratio variation
Load
8 bar IMEP
Abs. Inlet Pressure 2.5 bar
Engine Speed 1090 rpm
Swirl Ratio 1.7
• PPC possible at 8 bar IMEP on
compression ratios 12.4:1 and
14.3:1.
• Narrower operating range with
increased compression ratio.
SAE 2006-01-3412
Increased EGR

Effect of EGR and compression ratio at 12 bar IMEP
Load
12 bar IMEP
Abs. Inlet Pressure 3.0 bar
Engine Speed 1090 rpm
Swirl Ratio 1.7
• PPC only possible at 12 bar IMEP with
lowest compression ratio (12.4:1).
• Soot emissions relatively high
(compared to 8 bar IMEP).
SAE 2006-01-3412
17

The effect of EGR (and swirl) at 15 bar IMEP
Increased EGR
Increased EGR
SAE 2006-01-3412
• Low soot/low NOx combustion possible.
• Increased swirl lowers soot emissions, but
primarily before soot hump.
18

6
3
4
19

Gasoline instead of diesel fuel
Lic. Thesis by Henrik Nordgren 2005 and presented at DEER2005
20

Gasoline instead of diesel fuel
Lic. Thesis by Henrik Nordgren 2005
21

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

Gasoline tests in Scania D12
Bosch Common Rail
Prail max
1600 [bar]
Orifices 8 [-]
Orifice Diameter 0.18 [mm]
Umbrella Angle 120 [deg]
Engine / Dyno Spec
BMEPmax 15 [bar]
Vd 1951 [cm3]
Swirl ratio 2.9 [-]
Dilution
Lambda 1.5
EGR 50 %
Fuel: Gasoline or Ethanol
SAE 2009-01-2668
23

NOx [g/kWh]
CO [g/kWh]
Soot [FSN]
HC [g/kWh]
Emissions – different fuels
0.5
0.45
0.4
0.35
0.3
0.25
Ethanol
FR47330CVX
FR47331CVX
FR47333CVX
FR47334CVX
FR47335CVX
FR47336CVX
FR47338CVX
2.5
2
1.5
Ethanol
FR47330CVX
FR47331CVX
FR47333CVX
FR47334CVX
FR47335CVX
FR47336CVX
FR47338CVX
0.2
1
0.15
0.1
0.5
0.05
0
2 4 6 8 10 12 14 16 18 20
Gross IMEP [bar]
0
2 4 6 8 10 12 14 16 18 20
Gross IMEP [bar]
12
10
8
6
Ethanol
FR47330CVX
FR47331CVX
FR47333CVX
FR47334CVX
FR47335CVX
FR47336CVX
FR47338CVX
10
9
8
7
6
5
Ethanol
FR47330CVX
FR47331CVX
FR47333CVX
FR47334CVX
FR47335CVX
FR47336CVX
FR47338CVX
4
2
SAE 2010-01-0871
0
2 4 6 8 10 12 14 16 18 20
Gross IMEP [bar]
4
3
2
1
24
0
2 4 6 8 10 12 14 16 18 20
Gross IMEP [bar]

Energy flow in an IC engine
Brake
Combustion
*
Thermodynamic
*
GasExchange
*
Mechanical
FuelMEP
Combustion efficiency
QemisMEP
QhrMEP
QhtMEP
Thermodynamic efficiency
QlossMEP
Gross Indicated efficiency
IMEPgross
QexhMEP
Gas exchange efficiency
PMEP
Net Indicated efficiency
lMEPnet
Mechanical efficiency
FMEP
Brake efficiency
BMEP
25

[%]
Efficiencies 17.1:1
100
95
90
85
80
75
70
65
60
55
Combustion Efficiency
Thermal Efficiency
Gas Exchange Efficiency
Mechanical Efficiency
50
4 5 6 7 8 9 10 11 12 13
Gross IMEP [bar]
SAE 2009-01-2668
26
26

[%]
Efficiencies 14.3:1
100
95
90
85
80
75
70
65
60
55
Combustion Efficiency
Thermal Efficiency
Gas Exchange Efficiency
Mechanical Efficiency
50
4 6 8 10 12 14 16 18
Gross IMEP [bar]
SAE 2010-01-0871
27
27

Experimental Apparatus, Scania D13
XPI Common Rail
Orifices 8 [-]
Orifice Diameter 0.19 [mm]
Umbrella Angle 148 [deg]
Engine / Dyno Spec
BMEPmax 25 [bar]
Vd 2124 [cm3]
Swirl ratio 2.095 [-]
SAE 2010-01-2198
28
Standard piston 28 bowl, rc: 17.3:1

IMEP gross [bar]
Tested Load Area
25
Stable operational load vs. fuel type
20
15
10
5
0
20 30 40 50 60 70 80 90 100
RON [-]
29
29

Brake Efficiency [%]
D13 Running on Diesel & Gasoline
52
50
48
D13 Gasoline
D13 Diesel
46
44
42
40
38
36
34
5 10 15 20 25 30
Gross IMEP [bar]
D13 Diesel was calibrated by Scania and the calibration was done
to meet EU V legislation.
Average improvement of 16.6% points @ high load!!!
30

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

2013-01-0277
Close to Stoichiometric Partially
Premixed Combustion
- the Benefit of Ethanol in
Comparison to Conventional Fuels
Mengqin Shen, Martin Tuner and Bengt Johansson
Lund University

Experimental System, Scania D13
Scania D13 engine
Engine Piston Model
33

Fuel Properties
Fuel RON MON CN H/C O/C LHV
[MJ/kg]
Stoichiometric
A/F Ratio
MK 1 - - 54 1.83 0 43.15 14.49
Gasoline 69 66 - 1.98 0 43.80 14.68
99.5% Ethanol 108 89 - 3 0.5 26.64 9
34

CA50 [CAD ATDC]
Gross Indicated Efficiency[%]
Optimized Combustion phasing
6
5.5
5
4.5
57
56
MK1
Gasoline
Ethanol
4
55
O
3.5
3
2.5
54
53
52
0 1 2 3 4 5 6 7
2
1 1.2 CA50 [CAD 1.4 ATDC] 1.6 1.8
Gross indicated efficiency as a function of combustion phasing
(gasoline fuel, IMEP gross 11bar, FuelMEP 20.5 bar, λ=1.85,EGR=38%).
Combustion phasing (CA50) as a function of λ (Fuel MEP 20.5 bar).
[-]
35

RoHR/10 [J/CAD] / Injector Current
PPC-RoHR-diesel
200
150
=1.74
=1.58
=1.16
=1.05
100
50
0
-20 -10 0 10 20
Crank Angle [CAD ATDC]
36

RoHR/10 [J/CAD] / Injector Current
PPC-RoHR-gasoline
200
150
=1.74
=1.58
=1.16
=1.05
100
50
0
-20 -10 0 10 20
Crank Angle [CAD ATDC]
37

RoHR/10 [J/CAD] / Injector Current
PPC-RoHR-ethanol
200
150
=1.74
=1.58
=1.16
=1.05
100
50
0
-20 -10 0 10 20
Crank Angle [CAD ATDC]
38

Combustion Efficiency [%]
Gross Indicated Efficiency [%]
PPC-Efficiency
FuelMEP ~20.5 bar EGR~38%
100 55
18%
9%
6%
99.5
50
99
45
98.5
MK1
MK1 Gasoline
Gasoline Ethanol
Ethanol
40
98
97.5 35
1 1.2 1.4 1.6 1.8
[-]
39

Combustion Loss [%]
Exhaust Loss [%]
Heat Transfer Loss [%]
Efficiency & Losses
2
1.5
MK1
Gasoline
Ethanol
50
45
MK1
Gasoline
Ethanol
1
0.5
40
35
30
0
1 1.2 1.4 1.6 1.8
[-]
22
20
18
16
14
12
MK1
Gasoline
Ethanol
25
1 1.2 1.4 1.6 1.8
[-]
• Relative combustion loss is between 0.2% and
1.7% in all cases.
• Less relative exhaust loss with lower λ .
• More heat transfer in stoichiometric PPC due
to higher combustion temperature .High heat
transfer loss is the main reason for low
efficiency of diesel.
10
1 1.2 1.4 1.6 1.8
[-]
40

Soot [FSN]
UHC/NOx [g/kWh]
CO [g/kWh]
PPC-Emissions
10 1.4
1.2
8
1
CO[g/kWh]
NOx[g/kWh]
UHC[g/kWh]
7
MK1
Gasoline 6
Ethanol
5
6
0.8
4
0.6
4
0.4
2
0.2
3
2
1
0
0
1 1.2 1.4 1.6 1.8 2
[-] [-]
UHC, CO and NOx Soot emissions as as a function a function of λ of (FuelMEP λ (FuelMEP 20.5 bar, 20.5 EGR bar, 38%, EGR gasoline 38%). fuel).
41

Observations
It is possible to operate PPC from lean conditions to close
to stoichiometric conditions.
Gross indicated efficiency decreased for all the fuels in
close to stoichiometric operation:
– Ethanol showed higher efficiency and less efficiency reduction than gasoline
and diesel fuel.
Pronounced soot emission increase for diesel and gasoline.
Ethanol showed very low soot in all conditions.
Ethanol - Clean Stoichiometric PPC (with TWC).
42

Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

PPC- LD
Comparison of Negative Valve Overlap (NVO)
and Rebreathing Valve Strategies on a Gasoline
PPC Engine at Low Load and Idle Operating
Conditions
SAE Paper 2013-01-0902
Patrick Borgqvist, Per Tunestål, Bengt Johansson
Lund University
44

IMEP gross [bar]
Introduction
Partially Premixed Combustion – Light Duty Engine
25
20
15
10
5
0
20 30 40 50 60 70 80 90 100
RON [-]
PPC Operating Region from Heavy Duty Experiments [1]
• Goal: Increase attainable
operating region
- Means to reduce minimum
load:
Injection strategies
- Advanced pilot strategies
- Split main
Trapping hot residuals
- Temperature increase
- Dilution
- Stratification
Glow plug
[1] Manente, V., et al. “An Advanced Internal Combustion Engine Concept for Low Emissions and High
Efficiency from Idle to Max Load Using Gasoline Partially Premixed Combustion”, SAE 2010.01-2198
45

Experimental Setup – Volvo D5
Engine
Displacement
Number of
cylinders
Bore
Stroke
Compression
ratio
Valve timings
480 cm 3 (1 cyl)
5 (1 used)
81 mm
93.2 mm
16.5:1
Fully flexible
Fuel Injector
Standard D5 piston
Nozzle Holes 5
Umbrella Angle 140 deg
Hole Size
0.159 mm
46

IMEP gross [bar]
Fuel Specification
25
20
15
10
5
0
20 30 40 50 60 70 80 90 100
RON [-]
Fuel RON MON LHV
[Mj/kg]
A/F stoich
Gasoline 87 81 43.50 14.60
47

Pressure [bar] / Valve Lift [a.u.]
Negative Valve Overlap (NVO)
55
50
45
40
35
Pressure
Intake Valve
Exhaust Valve
NVO
Trap hot residual gas
to elevate the initial
temperature of the
fresh charge of the
subsequent cycle
30
25
20
NVO
Disadvantage
Gas-exchange
efficiency penalty
15
10
5
0
-200 -100 0 100 200 300 400 500
Crank Angle [CAD]
48

Rebreathing
55
50
45
40
Pressure [bar]
Intake Valve [a.u.]
Exhaust Valve [a.u.]
Advantage:
Improved gasexchange
efficiency
35
30
25
20
Minimum
possible NVO
Disadvantage:
Lower temperature of
re-inducted residual
gases compared to
trapped residuals???
15
10
5
Second exhaust
valve opening
0
-200 -100 0 100 200 300 400 500
Crank Angle [CAD]
49

IMEPgross [bar]
IMEPgross [bar]
Combustion stability
3.4
3.2
Rebreathing: std IMEPnet [bar]
0.4
3.4
3.2
NVO: std IMEPnet [bar]
0.4
3
0.35
3
0.35
2.8
0.3
2.8
0.3
2.6
2.4
0.25
2.6
2.4
0.25
2.2
0.2
2.2
0.2
2
0.15
2
0.15
1.8
0 20 40 60 80 100
Rebreathing [CAD]
1.8
60 80 100 120 140 160 180 200 220
NVO [CAD]
Similar improvement on combustion stability
with Rebreathing compared to NVO
50

IMEPgross [bar]
IMEPgross [bar]
Unburned Hydrocarbons
Rebreathing: Unburned Hydro-Carbon Emissions [ppm]
3.4
3.2
3
500
450
400
3.4
3.2
3
NVO: Unburned Hydro-Carbon Emissions [ppm]
500
450
400
2.8
350
2.8
350
2.6
300
2.6
300
2.4
250
2.4
250
2.2
200
2.2
200
2
150
2
150
1.8
0 20 40 60 80 100
Rebreathing [CAD]
100
1.8
60 80 100 120 140 160 180 200 220
NVO [CAD]
100
Similar improvement in hydro-carbon emissions
reduction with Rebreathing compared to NVO
51

IMEPgross [bar]
IMEPgross [bar]
Gas exchange Efficiency
3.4
3.2
3
Rebreathing: Gas-Exchange Efficiency [%]
96
94
3.4
3.2
3
NVO: Gas-Exchange Efficiency [%]
96
94
2.8
92
2.8
92
2.6
90
2.6
90
2.4
2.2
88
2.4
2.2
88
2
86
2
86
1.8
0 20 40 60 80 100
Rebreathing [CAD]
84
1.8
60 80 100 120 140 160 180 200 220
NVO [CAD]
84
Gas-exchange efficiency is significantly higher
with the Rebreathing strategy compared to NVO
52

IMEPnet [bar]
IMEPnet [bar]
Net Indicated Efficiency
3.2
Rebreathing: Net Indicated Efficiency [%]
40
3.2
NVO: Net Indicated Efficiency [%]
40
3
3
2.8
2.6
35
2.8
2.6
35
2.4
2.4
2.2
2
30
2.2
2
30
1.8
1.8
1.6
0 20 40 60 80 100
Rebreathing [CAD]
25
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
25
The net indicated efficiency is higher with the Rebreathing case.
Note, shown against IMEPnet
53

NVO Injection
50
45
40
35
30
25
20
15
10
5
Pressure [bar]
Valve Lift [a.u.]
Fuel Indicator [a.u.]
NVO Injection
Glow plug: ON
Engine speed: 800 rpm
Fuel: 87 RON Gasoline
Idea: Fuel reformation
to improve the main
combustion event
0
-200 -100 0 100 200 300 400 500
Crank Angle [CAD]
54

Rate of Heat Release [J/CAD]
Rate of Heat Release [J/CAD]
Effect of NVO Injection Timing
Effect of NVO-Pilot Injection Timing
Effect of NVO-Pilot Injection Timing
25 NVO: 220 CAD
20
15
Fuel Distribution
NVO/Main: 50/50 %
Lambda: 1.08 - 1.42
-22 CAD
-15 CAD
-10 CAD
-5 CAD
0 CAD
25 NVO: 220 CAD
20
15
Fuel Distribution
NVO/Main: 50/50 %
Lambda: 1.08-1.42
-22 CAD
-15 CAD
-10 CAD
-5 CAD
0 CAD
10
10
5
5
0
0
-5
-40 -30 -20 -10 0 10 20 30 40
Crank Angle (Gas-Exchange TDC) [CAD]
-5
-40 -30 -20 -10 0 10 20 30 40
Crank Angle [CAD]
55

IMEPgross [bar]
NVO Injection – Ignition Delay
56
2.6
2.4
Ignition Delay (CA10-SOI) [CAD] (NVO Injection)
18
16
Significant effect on the
ignition delay when NVO
is sufficiently high, from
200 CAD NVO
2.2
14
2
12
1.8
10
1.6
8
60 80 100 120 140 160 180 200 220
NVO [CAD]

IMEPgross [bar]
NVO Injection – Combustion stability
2.6
2.4
std IMEPnet [bar] (NVO Injection)
0.3
0.25
Significant improvement
on combustion stability
with NVO injection and a
high setting of NVO
2.2
2
0.2
1.8
0.15
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
0.1
57

IMEPgross [bar]
NVO Injection - HC
Unburned Hydro-Carbon Emissions [ppm] (NVO Injection)
2.6
2.4
2.2
700
650
600
550
500
Significant reduction of
unburned hydrocarbon
emissions with NVO
injection and a high
setting of NVO
2
1.8
1.6
450
400
350
60 80 100 120 140 160 180 200 220
NVO [CAD]
58

IMEPgross [bar]
NVO Injection - NOx
2.6
2.4
2.2
NOx [ppm] (NVO Injection)
120
100
80
High NOx emissions in the
intermediate region
between too low and too
high NVO settings
Low NOx emissions when
engine load is low and NVO
is sufficiently high
2
60
1.8
40
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
20
59

IMEPgross [bar]
NVO Injection -Soot
2.6
2.4
2.2
soot [FSN] (NVO Injection)
0.8
0.7
0.6
0.5
0.4
Soot emissions are
much higher when
NVO injection is
used
2
1.8
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
0.3
0.2
0.1
0
60

IMEPgross [bar]
NVO Injection -Lambda
IMEPgross [bar]
IMEPgross [bar]
soot [FSN] (NVO Injection)
Lambda [-] (NVO Injection)
2.6
0.8
0.7
2.6
2.4
2.2
2
2.8
2.6
2.4
2.2
2
1.8
2.4
2.2
2
1.8
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
NOx [ppm] (NVO Injection)
0.6
0.5
0.4
0.3
0.2
0.1
0
1.8
1.6
1.4
2.6
2.4
120
100
1.6
1.2
2.2
80
60 80 100 120 140 160 180 200 220
NVO [CAD]
2
60
1.8
40
61
1.6
60 80 100 120 140 160 180 200 220
NVO [CAD]
20

Putting it all Together
Comparison of different valve strategies and fuel
injection strategies, with optimized settings, at low
engine speed and load operating conditions
1. NVO, single injection
2. NVO with NVO injection, 200 CAD NVO
3. NVO with NVO injection, 220 CAD NVO
4. Rebreathing, single injection
62

std IMEPnet [bar]
Putting it all Together
0.4
0.35
0.3
NVO, sing. inj.
NVO, NVO inj. 200 NVO
NVO, NVO inj. 220 NVO
Reb, sing. inj.
Highest combustion
stability with the NVO
injection strategy
0.25
0.2
0.15
0.1
0.05
1 1.5 2 2.5 3 3.5
IMEPgross [bar]
63

soot [FSN]
Putting it all Together
1
0.9
0.8
0.7
0.6
NVO, sing. inj.
NVO, NVO inj. 200 NVO
NVO, NVO inj. 220 NVO
Reb, sing. inj.
Soot emissions are
significantly higher with
the NVO injection
strategy depending on
NVO setting
0.5
0.4
Higher NVO gives a lower
global air-fuel ratio
0.3
0.2
0.1
0
1 1.5 2 2.5 3 3.5
IMEPgross [bar]
64

Net Indicated Efficiency [%]
Putting it all Together
42
40
38
36
NVO, sing. inj.
NVO, NVO inj. 200 NVO
NVO, NVO inj. 220 NVO
Reb, sing. inj.
Net indicated efficiency
is highest with the
Rebreathing strategies
34
32
30
28
26
24
1 1.5 2 2.5 3 3.5
IMEPgross [bar]
65

Low Load Operating Strategy
Summary
NVO
NVO injection
Rebreathing
+ Lowest std of
IMEP
- soot emissions
+ highest indicated efficiency
- Low load limitation
• Tradeoff between Nox and UHC emissions
Gradually replace hot residuals with EGR
to suppress NOx emissions
2.0
2.5
IMEPgross [bar]
3.0
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Outline
• Combustion concepts
• PPC – background
• PPC with diesel fuel
• PPC with gasoline
• Low dilution PPC with ethanol
• Too low load with too high octane number
• Summary

Partially Premixed Combustion, PPC
• Compression Ignition should use gasoline not diesel
• PPC is the most efficient of all processes known (using one fuel)!
– Combustion Efficiency >99.8%
– Thermodynamic Efficiency= 55-57%
– Gas exchange efficiency reasonable
– Mechanical efficiency high as load can be high
• Load range 1.5-26 (30) bar IMEP
• Low enough emissions
– NOx, HC and CO below legal limits without catalytic aftertreatment
– PM low enough using ethanol and low with gasoline
68

The End
Thank you
69

Partially Premixed Combustion, PPC
– Why all diesel engines should be run on
gasoline
Bengt Johansson
Lund University