Testing of various fuel and additive

options in a compression-ignited

heavy-duty alcohol engine

2015 Polttomoottori- ja turboteknologian seminaari

Espoo, 7.5.2015

Timo Murtonen, Nils-Olof Nylund,

Mårten Westerholm & Christer Söderström (VTT)

Timo Huhtisaari (NEOT)

Gurpreet Singh (DTU)

2 2

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3 3

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1. Renewable Energy Sources

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platform; gasification and pyrolysis

technologies

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for new biobased value chains

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solar energy

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of FOUR technology

platforms

4 4

Background of the project

The International Energy Agency Implementing Agreement on Advanced

Motor Fuels has initiated an activity, Annex 46, on alcohols fuels for diesel

engines

The goal is to report the best possibilities for implementation of alcohols in

diesel engines

Two research partners, DTU Technical University of Denmark and VTT of

Finland teamed up in this activity, with technical support from Scania

DTU and VTT have their respective research agendas:

DTU is carrying out work with an experimental engine

VTT has conducted work using a commercial Scania heavy-duty

ethanol engine

5 5

Motivation

Especially in Europe, there is a shortage of middle distillates

The commercial vehicles are in practise running on diesel fuel only,

and diesel fuelled passenger cars have become increasingly popular

The demand of aviation kerosene is increasing, as well as the demand

of distillate fuels in the marine sector, due to the new limits on sulphur

dioxide emissions

Currently the greater part of the ethanol is used for low-level blending

into petrol

Using ethanol in diesel engines would bring about two major benefits:

Alleviate the shortage of middle distillates

Enable the use of ethanol with high engine efficiency

6 6

Scania ethanol engine

Scania DC9 E02 270 EEV

Model year 2011

5 cylinders

Displacement: 8.9 dm3

Compression ratio 28:1

(corresponding diesel engine 18:1)

Power: 198 kW / 1900 rpm

Torque: 1200 Nm / 1100-1400 rpm

Unit injectors, EGR, oxidation catalyst

However, the engine was tested w/o catalyst

Emission level Euro5/EEV

Additional fuel injectors were installed into the intake manifold

7 7

Instrumentation

For emission measurements, the apparatus corresponds to the

requirements of the European Directive 1999/96/EC on emission

measurements of heavy-duty engines

However, as a steady-state engine dynamometer was used, the

measurements were basically carried out using the European Steady

Cycle (ESC) procedure

Emissions of unburned alcohol and aldehydes were measured using

an FTIR instrument.

8 8

Test programme

The objectives of the test programme were to test:

Three alternative additive packages, all approved by Scania

Three different ethanol water concentrations (appr. 0, 5 and 10 %

water by weight)

Two fuels containing methanol; one blend of ethanol and methanol

and neat methanol

Whether injection of fuel into the manifold would facilitate ignition

on the main fuel shot

It must be pointed out that Scania doesn’t approve the use of methanol

containing fuels in its ethanol engine.

9 9

Test programme

Performance indicators monitored included, among other things:

Energy consumption

Carbon dioxide (CO2) emission

Regulated emissions (carbon monoxide CO, unburned

hydrocarbons HC*, nitrogen oxides NOx, particulate matter PM)

Unregulated emissions (unburned alcohol, aldehydes)

Ignition delay and heat release

*When running on alcohols, the hydrocarbon result is not accurate. However, the

HC values can with caution be used for fuel to fuel comparisons.

10 10

Test fuels

Density Ethanol H2O Methanol Carbon Hydrogen LHV

kg/m3 mass-% mass-% mass-% mass-% mass-% MJ/kg

Fuel 1 818,50 88,90 5,70 0,10 48,80 13,10 24,90

Fuel 2 813,90 90,50 5,52 0,50 47,80 13,30 24,70

Fuel 3 819,10 88,70 5,80 0,50 47,20 12,60 25,00

Fuel 4 804,40 92,30 0,44 0,10 49,60 12,50 26,80

Fuel 5 831,80 84,00 10,09 0,10 45,10 12,40 23,90

Fuel 6 819,50 57,00 5,14 28,70 43,20 12,30 23,20

Fuel 7 807,90 3,20 0,32 87,90 37,70 12,10 20,40

11 11

Differences in energy consumption within the measurement accuracy

Energy consumptions has been calculated using the analysed LHVs

(lower heating values)

0% 1% 2% 1% 1% -1 %

0,01,02,03,04,05,06,07,08,09,0

10,0C

on

sum

pti

on

, [M

J/kW

h]

Energy consumption, ESC test cycleFuels 4-7 with additive 1

12 12

0% 0% 0% 0% -1%-2 %

0

100

200

300

400

500

600

700

800Em

issi

on

, [g/

kWh

]

CO2 emission, ESC test cycleFuels 4-7 with additive 1

13 13

EEV emission limit for CO emission is 1.5 g/kWh (ESC test cycle)

Engine was measured without catalyst

-8% -6%+10%

-7%

-24%

-54%

0,0

0,2

0,4

0,6

0,8

1,0Em

issi

on

, [g/

kWh

]

CO emission, ESC test cycleFuels 4-7 with additive 1

14 14

EEV emission limit for HC emission is 0.25 g/kWh (ESC test cycle)

Engine was measured without catalyst

0% -1% -6% 2-6%

-29 %

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8Em

issi

on

, [g/

kWh

]

HC emission, ESC test cycleFuels 4-7 with additive 1

15 15

EEV emission limit for NOx emission is 2.0 g/kWh (ESC test cycle)

NOx emission with Fuel 7 is most likely affected by the extended injection times

+2% +4% +10% -3% -2%

+23 %

0,0

0,5

1,0

1,5

2,0

2,5

3,0Em

issi

on

, [g/

kWh

]

NOx emission, ESC test cycle

Fuels 4-7 with additive 1

16 16

EEV emission limit for PM emission is 20 mg/kWh (ESC test cycle)

PM emission with methanol fuels is high

No visible soot on the filters so the result must be an indication

of semivolatile components or artifacts

-4 -9% -4% 0 +16%

+67 %

05

101520253035404550

Emis

sio

n, [

mg/

kWh

]

PM emission, ESC test cycleFuels 4-7 with additive 1

17 17

Summary of fuel comparison

Engine operated “equally and normally” with fuels 1-6

Equal energy consumption with all fuels

No real differences between additive packages could be found

The normal dosing of ignition improver additive is sufficient for stable engine

operation in all conditions

Leaving out the water increases both CO and NOx emissions, whereas adding

water reduces both these emissions marginally (in the case of ethanol)

Some effects of methanol on emissions and cylinder pressure

All in all the testing shows that the direct injection ethanol engine concept has

some built-in multifuel capabilities

18

Can the need for

additive be reduced?

19 19

Intake manifold injection & amount of ignition

additive

VTT tested an idea for enhancing the start of combustion

A small amount of ethanol is injected into intake manifold for

shortening the ignition delay

Would it be possible to decrease the amount of ignition additive?

A sequential 5-point injection system was added to Scania engine for

injecting fuel to the intake manifold

The system would not require an additional fluid, just a relatively simple

low-pressure injection system

20 20

Implementation of the idea

A sequential 5-point injection system was added to Scania engine for

injecting fuel to the intake manifold

Commercial “open” ECU was used to control the system

21 21

Measurements with the intake manifold injection

Test runs with fuels having a different additive levels were performed with

and without intake manifold fuel injection

When additive level was decreased to ¼ compared to commercial ED95

fuel, a clear difference with and w/o intake manifold injection was found out

Without intake manifold injection

1800 rpm / 25% load With intake manifold injection

1800 rpm / 25% load

22 22

Measurements with the intake manifold injection

Crank angle location for 10% heat release value indicates the differences in

start of combustion

23 23

Conclusions – intake manifold injection

Intake manifold injection was tested at high rpm and low load, the

conditions most critical for ignition

Intake manifold injection did indeed facilitate ignition of the fuel

In the preliminary tests using intake manifold injection increased overall

fuel consumption

Further testing to optimise, e.g., amount of pilot fuel and timing of main

fuel injection, is needed to really show the potential of the concept

In a common-rail engine pre-injection could be realised without

additional hardware

24 24

Acknowledgements

DTU Technical University of Denmark serves as operating agent and

coordinator of the IEA Advanced Motor Fuels project “Annex 46:

Alcohols fuels for diesel engines”

The work reported here is Finland’s contribution to this project

VTT received technical support from Scania and financial support from

North European Oil Trade NEOT and St1.