TECHNICAL UNIVERSITY OF RADOM

TECHNICAL UNIVERSITY OF RADOM Dr Grzegorz Pawlak Combustion of Alternative Fuels in IC Engines Ecology and Safety as a Driving Force in the Development of Vehicles

Challenge 120 g/km emission of CO2

New Rules

Fuels Energy Content and Costs for Emission

How to control combustion?

Engine Development The Idea CO2 emission Fuel consumption Nitrogen oxides

Combustion in Compression Ignition Engine

What parameters can be used to control combustion proces in CI engine?

Creation of Combustion Products Concentration of soot, NO and other combustion products in combustion chamber of DI diesel engine [3]

NOx creation

Fuel Characteristics [2], [3] Natural Gas Carbon content [mass %] 73,3 85,9 Hydrogen content [mass %] 23,9 14,0 Oxygen content [mass %] 0,4 0,05 Carbon-to-hydrogen ratio 0,25-0.33 0,16 Diesel Oil Relative molar mass 17-20 ~170 Density at 0 oc and 1,013 bar [kg/m3] ~0,83 840 Boiling temperature [ C / 1 bar] -162 from 170 to 380 Autoignition temperature [ C] 540-560 320 330 Octane number 120-130 - Cetane number - 52-56 Methane number 69-99 -

Fuel Characteristics [2], [3] Natural Gas Diesel Oil Stoichiometric air/fuel ratio [mass] 17,2 14,5 Vapour flammability limits [Volume %] 5-15 - Flammability limits [lambda] 0,7 2,1 0,19-0,98 Lower heating/calorific value [MJ/kg] 38-50 42,6 Methane concentration [Volume %] 80-99 - Ethane concentration [Volume %] 2,7 4.6 - Nitrogen concentration [Volume %] 0,1-15 - Carbon dioxide concentration [Volume %] 1 5 - Sulphur concentration [ppm, mass] < 5 < 50 Specific CO2 formation [g/mj] 38-50 72

Combustion in Dual Fuel Engine The scheme of gas and diesel oil combustion [5]

Droplets Distribution 100 100 80 60 R i 40 20 0 0 0 0.03 0.06 0.09 0.12 0.15 0 d i 0.15 Rosin Rammler formula: R i 100 exp d i dm n R distribution of droplets in spray dm diameter of average droplet di diamenter of each droplet

Mixture Creation and Combustion Model (a) (b) Concentration of gas (a) and diesel oil (b) in the combustion chamber KIVA2R3

Droplet Mass and Heat Transfers Qd total heat flow rate from the ambient gas Ql heat flow rate used to increase the droplet temperature m mass Lvap- latent heat of vaporization [17]

Fuel Vapour Concentration Around the Droplet 0.838 1 0.8 Yr i 0.6 Yr_a i u_ch4 0.4 0.2 3.909 10 3 0 0 2 10 5 4 10 5 6 10 5 8 10 5 1 10 4 1.2 10 4 1.4 10 4 1.6 10 4 1.8 10 4 2 10 4 2.2 10 4 2.4 10 4 2.6 10 4 2.8 10 4 3 10 4 0 r i 2.99 10 4

Mixture Composition Around the Droplet Air Concentration and Flameability Limits of the Mixture 1 1 0.994 0.934 0.9 0.8 0.7 air_mix i air_mix_a i gg_pal_ch4 dg_pal_ch4 0.6 0.5 0.4 0.3 0.2 0.1 0 0 0 2 10 5 4 10 5 6 10 5 8 10 5 1 10 4 1.2 10 4 1.4 10 4 1.6 10 4 1.8 10 4 2 10 4 2.2 10 4 2.4 10 4 2.6 10 4 2.8 10 4 3 10 4 0 r i 2.99 10 4

Droplet Live din initial droplet diameter d diameter of droplet after time t t time β fuel parameter (constant) ρ mixture (air+fuel in gas state)density ρl density of the liquid fuel B transfer number D diffusion coefficient Yfu mass fraction of the fuel

Evaporation Time Evaporation time will be shorter when: the diffusion coefficient is high the initial diameter is small the transfer number is large

Mixture Formation and Combustion in Compression Ignition Engine Ignition delay [ms]: i n 6 1 ( 0.36 0.22 S) exp E i R T 1 17190 21.2 p 12.4 0.63 where: E i 618480 CN i 25 30 E - activation energy [J/mol] s i n engine speed [rpm] T temperature [K] p pressure [bar] S mean piston speed [m/s] R universal gas constant 8,3143 J/(mol K) CN cetane number 0 1 CN i 60

Burning Velocity Laminar burning velocity for different fuels as a function of equivalence ratio [3]

Mixture Formation and Combustion in Compression Ignition Engine Pressure Diagram P [MPa] 8 7 6 5 4 3 2 1 diesel oil gas + diesel oil 0 240 270 300 330 360 390 420 450 480 [ o OWK] Comparison of pressure diagrams for engine fuelled with diesel oil and with diesel oil with gas together

Combustion Parameters Changes in Pressure Diagram

Combustion Parameters Maximum combustion pressure as function of natural gas mass ratio at 2000 rpm for various engine loads [13] Ignition delay and combustion duration as a function of natural gas mass ratio at 2000 rpm for various engine loads [13]

Emission Soot opacity and nitric oxide as function of natural gas mass ratio at 2000 rpm for various engine loads [13] Unburned hydrocarbon and carbon monoxide as function of natural gas mass ratio at 2000 rpm for various engine loads [13]

Concepts of Mixture Formation Concept of biform mixture formation in different piston cavity space in a dual-fuel engine [6]

Shape of Combustion Chamber Combustion chamber configuration [6] In-cylinder temperature and ROHR for the dual-fuel diesel combustion with conventional toroidal and divided cavities (Fgas = 88%, IMEP=0,57 MPa) [6]

Regulating Parameters 1. CNG-diesel oil ratio (pilot dose mass or air throttling) 2. Injection timing of diesel oil pilot dose 3. % EGR

Fuels characteristic Ethanol Diesel Oil Carbon content [mass %] 52,2 85,9 Hydrogen content [mass %] 13 14,0 Oxygen content [mass %] 34,8 0,05 Density at 0 oc and 1,013 bar [kg/m3] 785 840 Boiling temperature [ C / 1 bar] -162 from 170 to 380 Autoignition temperature [ C] 665 320 330 Octane number 107 - Cetane number - 52-56 Stoichiometric air/fuel ratio [mass] 9,5 14,5 Flammability limits [lambda] 0,3 2,06 0,19-0,98 Lower heating/calorific value [MJ/kg] 26,9 42,6

V_wd [1/st] cisnienie [MPa] X Dual Fuel Engine (diesel oil + alkohol) 5 GMP 1 0.9 4 czysty olej napędowy (ON), =0 E ON + dawka etanolu 0,099 kj/cykl, =0,111 E ON + dawka etanolu 0,240 kj/cykl, =0,270 E ON + dawka etanolu 0,520 kj/cykl, =0,503 E 0.8 0.7 0.6 0.5 3 0.4 0.3 2 0.2 0.1 0 czysty olej napędowy (ON), E =0 ON + dawka etanolu 0,099kJ/cykl;, E =0,111 ON + dawka etanolu 0,240 kj/cykl;, E =0,270 ON + dawka etanolu 0,520 kj/cykl, E =0,503 340 350 360 370 380 390 400 410 KOWK [st] 1 0 210 260 310 360 410 460 510 KOWK [st] 0.09 0.08 0.07 0.06 0.05 czysty olej napędowy (ON), =0 E ON + dawka etanolu 0,099 kj/cykl; =0,112 E ON + dawka etanolu 0,240 kj/cykl; =0,270 E ON + dawka etanolu 0,520 kj/cykl; =0,503 E 0.04 n=2200 rpm, T = 20 Nm α = 30 deg BTDC 0.03 0.02 0.01 0 340 350 360 370 380 390 400 410 KOWK [st]

NOx emission NO x [ppm] 325 300 275 Stezenie NO x przy M = 10 N m i n = 2200 obr/min Alfa ON 25 o przed GMP Alfa ON 30 o przed GMP Alfa ON 35 o przed GMP 250 225 200 175 150 125 n = 2200 rpm, T = 20 Nm α = 30 deg BTDC 100 75 50 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 E

HC [ppm] Hydrocarbon emission 200 180 160 Stezenie HC przy M = 20 N m i n = 2200 obr/min Alfa ON 25 o przed GMP Alfa ON 30 o przed GMP Alfa ON 35 o przed GMP n=2200 rpm, T = 20 N m α = 30 deg BTDC 140 120 100 80 60 40 0 0.1 0.2 0.3 0.4 0.5 0.6 E

Zadymienie D [%] Soot emission 90 80 70 60 Zadymienie spalin przy M=20Nm i n=2200obr/min Alfa ON 25 o przed GMP Alfa ON 30 o przed GMP Alfa ON 35 o przed GMP n=2200 rpm, T = 20 N m α = 30 deg BTDC 50 40 30 20 10 0 0 0.1 0.2 0.3 0.4 0.5 0.6 E

Regulating Parameters 1. Ethanol-diesel oil ratio (pilot dose mass or air throttling) 2. Injection timing of diesel oil pilot dose

Practical solutions CI Engine fuelled with: 1. CNG + Diesel Oil 2. Ethanol + Ingredients

Dual Fuel Combustion Systems Combustion system of dual fuel engine with direct gas injection [8]

Direct Injection of Gas and Diesel Oil How does the system work? In this system, natural gas injected at the end of the compression stroke. The injection contains a pilot of 3 to 15 percent diesel fuel depending on the load characteristics of the application. The diesel fuel is injected milliseconds before the natural gas fuel, which instantaneously ignites the mixture. The system uses on dual fuel injector per cylinder that contains two needles (a needle within a needle with separate injector holes for each fuel). The diesel fuel also lubricates the injector and other moving parts [8].

Dual Fuel Engine Performance CATERPILLAR C-10 DFNG ENGINE [9]

Benefits of Dual Fuellig of CI Engine with Diesel Oil and CNG Lower cost of exploitation (about 65% of transport company cost in Poland is a fuel) Possibility of decreasing of engine emission Application of alternative fuel Possibility of adaptation of older generation of CI engines High engine torque for low engine speed Flexibility (it is possible to run the engine only on diesel oil or CNG-diesel oil mixture)

Ethanol Bus Scania with DSI9E engine (V=8,9 l, compression ratio=24) fuelled with ethanol E95 Ethanol E95 : ethanol 92,2-95 % autoignition activator 5 % ether 2,3 % isobuthanol 0,5 % inhibitor of corrosion 90 ppm

Application of new fuels pushes forward automotive development

Homogeneous Charge Compression Ignition The Idea How does HCCI work? 1. A homogeneous mixture of fuel, air, and EGR is fed into the combustion chamber. 2. The mixture is compressed so that it spontaneously starts to react throughout the cylinder. 3. The combustion of the lean or diluted mixture occurs at a temperature low enough... 4. to avoid NOx-formation.

HCCI Control

HCCI Control What is controlled: Maximum pressure (possibly knock) Angle of peak pressure Cycle by cycle variation It could be changed by: amount of fuel and air (variable valve actuation) EGR (temperature and composition of the mixture)

Idea how to organise combustion process?

TECHNICAL UNIVERSITY OF RADOM Thank you for attention Ecology and Safety as a Driving Force in the Development of Vehicles