Session 4&5 of the course of Internal combustion Engines.pptx

Design and calculation of ICE

1. Fuel systems – CI engines

2. Outline Objective of fuel systems Classification of fuel systems Evolution – powertrains, technology, fuel pressure, regulations Objectives and requirements of Diesel fuel injection systems Evolution of Diesel fuel injection systems Diesel fuel injection system – architecture/components In-line pump systems Distributor-type pump injection systems Unit-Injector injection systems Unit-Pump injection systems Common-rail systems Fuel Injectors Exhaust system

3. 27 de outubro de 2016 | 3 Objective of fuel injection systems To deliver fuel into the cylinders at proper timings (optimizing power, preventing pre-ignition) in accurate amounts (for optimal A/F ratio, function of load, RPM, engine temperature,…) in the right form (fuel atomization, for full combustion and lower emissions)

4. Classification of fuel systems (CI and SI) Op e r a ti n g principle ICE type single or multiple injectors di r e ct/indi r e ct injection technology Mechanical SI (single point) indirect Carburetor Diesel (multi-point) direct or indirect Injection Pump (in-line or rotary), few hundred bars Electronic SI SPI indirect in the throttle body, few bars MPI indirect Fuel rail, few bars direct Fuel rail, tens of bars Diesel (multi-point) direct Fuel-rail or pump/unit- injection, hundreds to thousands of bars

5. ubro de 2016 | 5 Evolution – market share (Europe and USA)

6. Evolution – light vehicles powertrain (current)

7. Evolution – light vehicles powertrain (forecast)

8. Evolution – European emission standards (Diesel)

9. Evolution – European emission standards

10. Evolution – emission reduction vs. technologies

11. Evolution – emission reduction vs. technologies

12. Evolution – emission reduction vs. technologies

13. Evolution – fuel pressure vs. models 1927: 100 bar 1 st series-production inline injection pump ; MAN truck 1975: 300 bar 1 st VE distributor injection pump (VW Golf D) 1989: 900 bar Axial-piston pump (Audi 100 TDI) 1995: 1 st Diesel common-rail system for trucks ( by Denso ) 1997: 1,350 bar 1 st common rail system for light-duty (Bosch/fiat, Alfa-Romeo 156 2.4 JTD) 1998: 1,500 – 1,750 bar VP 44 radial-piston pump (Opel Vectra, Audi A6 2.5 TDI, 1996; BMW 320d) 1998: 2,050 bar 1 st unit injector system (VW Passat TDI, 1998) 2003: > 2,000 bar Bosch common rail with piezo injector (first deployed in the Audi A6 3.0 TDI, 2003/4) 2013/14: 2,500 bar Denso releases 1 st common-rail system with 2500 bar (2013) Bosch releases CRS3-25 common-rail system with 2500 bar (2014)

14. de outubro de 2016 | 14 Evolution – supercharging/injection pressures

15. Evolution – production of different Diesel technologies Light vehicles ( by Bosch )

16. Evolution – production of different Diesel technologies Commercial and heavy-duty vehicles ( by Bosch )

17. Classification of CI fuel systems Class. according to when/how high fuel-pressure is produced High pressure is generated when injection occurs (dependent on RPM) In-line pump systems ( PE by Bosch ) Distributor-pump systems ( VE by Bosch ) axial-piston radial piston Unit-Injector Systems ( UIS by Bosch ) Unit-Pump Systems ( UPS by Bosch ) High pressure is always available (independent of RPM) Accumulator-type = Common-Rail Systems ( CRS by Bosch )

18. Classification of CI fuel systems Distributor pump Co m m o n - rail Unit- Injector Unit- pu m p

19. 016 | 19 Classification of CI fuel systems CI fuel systems can be classified according to where the fuel is injected Indirect injection (right) Direct injection (left)

20. 27 de outubro de 2016 | 20 Classification of CI fuel systems Direct Injection Indirect Injection

21. Requirements of CI injection systems Generic objectives of a fuel injection system Reduce emissions and fuel consumption Maximize engine power/performance Requirements atomize & pulverize fuel very finely (better combustion)  high pressure differential (btw fuel and combustion chamber) pressure inside cylinder  100 bar  high fuel pressure (> 300 bar)  optimal-spray injectors optimize injection timings and quantity (mass)  ECU-control (real-time, closed-loop)  fast-response injectors (piezo-electric) minimize pollutant emissions (according to regulations)  EGR, catalyst, SCR (Selective Catalytic Reduction) , particulate filters

22. Diesel fuel injection system – architecture/components Major component groups Low (fuel) pressure system deliver fuel from the tank to the fuel injection system fuel tank, fuel supply pump, fuel filter. High (fuel) pressure system create high pressure, measure, control and deliver the fuel to the combustion chamber high pressure pump, fuel injector; common-rail systems also include a high-pressure fuel accumulator (aka fuel rail ) Control system sensors, ECU, actuators in purely mechanical systems, control is performed by the high-pressure pump

23. Diesel fuel injection system – architecture/components Overall architecture and main components Common-rail type Injection-pump type

24. Diesel fuel injection system – low pressure circuit Main objective store fuel and feed the high-pressure circuit Main components Fuel tank store and cool the fuel Feed pump (aka fuel supply , low-pressure, transfer, lift or primary pump) not used in some fuel systems (high-pressure pump does the job) drag fuel from the tank and push it to the high-pressure pump usually includes a pre-filter Fuel filter filters impurities and purges water out of the fuel circuit prevents engine damage & improves its performance Fuel heater avoid the forming of paraffin wax, in case of low temperatures (which can stop the fuel flow) can be embedded into the fuel filter Charcoal (carbon) canister transforms evaporated fuel into liquid fuel Pipes fuel feed/return

25. Diesel fuel injection system – low pressure circuit Fuel tank main objectives store the fuel receive the fuel return (backflow) from the high-pressure components host other components, e.g. feed pump and fuel level gauge Must feature optimal volume, shape and location robustness to prevent spillage and leakage, even in case of an accident, e.g. rollover; must also be fire-proof fuel overheating and overpressure detection and mitigation, via ventilation and safety valves fuel level gauge electrical harness for feed pump (if located inside the tank)

26. Diesel fuel injection system – low pressure circuit Tank + canister example (Mercedes SLK320)

27. Diesel fuel injection system – low pressure circuit Feed pump (mechanically-driven) driven by camshaft, outside the tank

28. Diesel fuel injection system – low pressure circuit Feed pump (electrically-driven) ECU-controlled, inside the tank produces a few bars

29. Diesel fuel injection system – low pressure circuit Fuel filters remove  m particles water (manual or automatic draining) Water sensor signals full water chamber

30. Diesel fuel injection system – low pressure circuit Fuel heater avoids wax forming for low temperatures upstream the filter inside/outside filter casing

31. Diesel fuel injection system – in-line pump systems One pump element for each engine cylinder elements arranged in a row activated by a camshaft in the in-line pump driven by the combustion engine via control wheels or chains Each pump element is connected via a high-pressure line to an injection nozzle installed in the cylinder head by means of a nozzle holder nowadays, the amount of fuel injected, and the start of delivery are controlled by ECU. In-line fuel-injection pumps achieve injection pressures of up to 1,300 bar

32. v eis Diesel fuel injection system – in-line pump systems Amount of injected fuel depends on factory settings, manual adjustments, RPM, coolant temperature, barometric pressure, accelerator position, start & stop solenoids

33. Diesel fuel injection system – in-line pump systems

34. Diesel fuel injection system – in-line pump systems

35. Diesel fuel injection system – distributor-pump systems Distributor pumps classification axial piston or radial piston purely mechanically-controlled or ECU-controlled

36. Diesel fuel injection system – distributor-pump systems Axial-piston pump basics pistons attached to a cylindrical block which move in the same direction as the block's centerline (axially) reliable operation and simple design

37. Diesel fuel injection system – distributor-pump systems Radial-piston pump basics pistons arranged like wheel spokes around a cylindrical block. drive shaft rotates this cylindrical block which pushes or slings the pistons, causing compression and expansion eccentricity between the piston housing and cylinder block centerlines determines the piston stroke low noise level and high efficiency http://www.globalspec.com/learnmore/flow_transfer_ control/pumps/piston_plunger_pumps

38. Diesel fuel injection system – distributor-pump systems Mechanically-controlled (governed) axial-piston distributor fuel-injection pump (VE by Bosch ) typically, up to 1100 bar; up to 1200 bar (SOTA VE-EDC)

39. Diesel fuel injection system – distributor-pump systems VE pump

40. 7 de outubro de 2016 | 39 Diesel fuel injection system – distributor-pump systems VE pump

41. Diesel fuel injection system – distributor-pump systems Feed pump (aka vane pump) draws fuel through the filter from the tank and supplies it to the distributor plunger as the rotor spins, centrifugal force holds the vanes against the walls of the pressure chamber off-center (eccentric layout) of the rotor and pressure chamber "squeezes" fuel trapped between the vanes and forces it out the delivery port delivery pressure 3-7 bar, depending on RPM

42. tubro de 2016 | 41 Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution injection pump driveshaft turns vane pump, distributor plunger, and cam plate (as a unit) springs hold the cam plate and distributor plunger against stationary rollers  the plunger moves back and forth as it turns

43. tubro de 2016 | 42 Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution whenever an intake port on the plunger is in line with the filling port in the pump body, fuel from the vane pump fills the high-pressure chamber.

44. 27 de outubro de 2016 | 43 Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution as the plunger continues to turn, the outlet port lines up with the injection ports in the pump body the cam plate pushes the plunger to “squeeze” the fuel in the high-pressure chamber

45. 27 de outubro de 2016 | 44 Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution the delivery valve opens under pressure and high-pressure fuel is supplied to the injector The ports in the pump are arranged so that the injectors receive fuel in the cylinder firing sequence

46. Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution Complete sequence A – suction B – delivery

47. Diesel fuel injection system – distributor-pump systems High-pressure compression and distribution Complete sequence

48. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity amount of fuel injected is controlled by a governor injection cut-off point depends on RPM & engine load controlled by the metering sleeve on the distributor plunger metering sleeve covers and uncovers a relief port in the plunger – uncovering the relief port stops injection

49. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity – engine start when engine is not running, starting spring presses the starting lever to the left so that the metering sleeve moves to the right. distributor plunger must move further to expose the relief port injection lasts longer so that more fuel is supplied during starting

50. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity – idle speed flyweights partially expanded  governor sleeve moves right starting lever pushes control lever  metering sleeve moves left distributor plunger now moves less to expose the relief port. injection lasts shorter so that less fuel is supplied at idle

51. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity – acceleration control lever is pulled to the left by the accelerator lever metering sleeve is moved to the right (fuel is injected before relief port is uncovered) RPM increases until governor movement “neutralizes” effect of pedal linkage

52. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity – max RPM accelerator lever at “full load”  maximum RPM flyweights stretch governor spring  control lever moves right metering sleeve moves left (uncovers relief port at the beginning of the distribution plunger stroke) LESS fuel injected and top speed is limited.

53. Diesel fuel injection system – distributor-pump systems Governing the fuel injection quantity – 4 states S T A R TI N G I D LE A C CEL E R A TION MAX RPM

54. Diesel fuel injection system – distributor-pump systems Governing the fuel injection timing (advance) as RPM increases, stroke timing becomes shorter and injection timing becomes longer burning must begin sooner to ensure that peak combustion pressures still occur at the most efficient point after TDC injection timing is advanced by hydraulic piston in injection pump

55. Diesel fuel injection system – distributor-pump systems Governing the fuel injection timing (advance) > RPM  fuel pressure from the vane pump vane pump pressure pushes the injection advance piston to the left against the spring so that the roller housing turns slightly distributor plunger beings injection sooner

56. Diesel fuel injection system – distributor-pump systems Governing the fuel injection timing/quantity

57. Diesel fuel injection system – distributor-pump systems Bosch VP44 radial-piston injection pump introduced in 1998 to meet emissions standards (before common rail fuel systems were available, in the 2000s) and to reduce fuel consumption direct-injection system for small to medium-size engines 2 ECUs control fuel injection quantity/timing injection pressures up to 1600 bar

58. 27 de outubro de 2016 | 56 Diesel fuel injection system – distributor-pump systems Bosch VP44 radial-piston injection pump Engine Control Unit – ECU (aka ECM ) receives and processes data from sensors commands FPCM (via CAN) for target fueling and timing Fuel Pump Control Module – FPCM embedded in the injection pump contains fueling, timing and diagnostic data. responds to ECM commands according to fueling data and timing in its memory and actuates fueling+timing solenoids

59. e 2016 | 57 Diesel fuel injection system – distributor-pump systems Bosch VP44 radial-piston injection pump section of the circuit diagram & sensors

60. Diesel fuel injection system – distributor-pump systems Bosch VP44 radial-piston injection pump fuel injection flow and fuel injection timing (advance) control

61. Diesel fuel injection system – unit-injector systems Unit Injector (UIS) and Unit Pump (UPS) systems each cylinder is served by a separate injection pumping element or injection pump in close proximity to the cylinder Unit Pump (UP) systems enable short high pressure fuel lines (pump close to injector) Unit injector (UI) systems combine the pumping element and the injector into one assembly eliminates high pressure lines  < line dynamics problems (e.g. delay) > injection pressures (up to 2500 bar)

62. Diesel fuel injection system – unit-injector systems Unit Injector Systems (UIS) pressure generation unit camshaft rocker arm (roller type) electromagnetic valve injection nozzle

63. Diesel fuel injection system – unit-injector systems UIS camshaft and basic control diagram engine camshaft has 3 cams (lobes) per cylinder ECU controls fuel injection quantity/timing Admission & Exhaust cams Unit injector cam

64. Diesel fuel injection system – unit-injector systems Unit injector components Electromagnetic (solenoid) valve Pump tappet Pump piston ( plunger ) High pressure chamber ( barrel ) Nozzle assembly spring nozzle check nozzle tip

65. Diesel fuel injection system – unit-injector systems Fuel injection cycle Filling admission of fuel into the (high-pressure) fuel chamber Pre-injection preparation for the injection phase Injection high-pressure fuel injection into the combustion chamber End of injection

66. Sis t emas Aut o mó v eis Diesel fuel injection system – unit-injector systems Filling phase rocker arm releases tappet (tappet spring pushes it upwards) plunger is pulled up by the tappet and the tappet spring upward movement of the plunger causes the pressure in the plunger cavity to drop below fuel supply pressure Fuel flows from the fuel supply passage (via open poppet valve) into the plunger cavity, until as the plunger travels upward when plunger reaches top of stroke, plunger cavity is full of fuel and fuel flow stops this is the beginning of pre-injection Mechanical movement Moving parts Fuel movement

67. Sis t emas Aut o mó v eis Diesel fuel injection system – unit-injector systems Pre-injection phase pre-injection starts with injector tappet/plunger at the top of the fuel injection stroke plunger cavity full of fuel poppet valve opened nozzle closed rocker arm starts pushing tappet/plunger downwards fuel leaves the plunger cavity, flowing through the open poppet valve to the fuel supply passage in the cylinder head pre-injection continues until solenoid is energized, closing the poppet valve and triggering injection (next) Fuel supply pressure Injection pressure Moving parts Mechanical movement Fuel movement

68. Sis t emas Aut o mó v eis Diesel fuel injection system – unit-injector systems Injection phase (rocker arm keeps pushing tappet/plunger down) ECU sends a current to the electromagnetic valve solenoid, attracting the armature poppet valve closes, blocking flow path for the fuel that was leaving the high pressure chamber (fuel return line to the tank) plunger continues its downward movement, compressing fuel in the high-pressure chamber when fuel pressure reaches threshold, high pressure fuel force overcomes spring force high-pressure fuel flows out of the injector nozzle (start of injection) injection continues while plunger moves downwards and energized solenoid holds the poppet valve closed Fuel supply pressure Injection pressure Moving parts Mechanical movement Fuel movement

69. Sis t emas Aut o mó v eis Diesel fuel injection system – unit-injector systems End of injection phase ECU stops current flow to the solenoid, releasing the armature poppet valve opens, unblocking flow path for the fuel to leave the high pressure chamber this results in a rapid drop in injection pressure when injection pressure drops below a certain threshold, the force of the nozzle spring overcomes the force of the fuel pressure injection nozzle closes and fuel injection stops Fuel supply pressure Moving parts

70. Diesel fuel injecti on syste m – uni t - inj e ctor system s Sis t emas Aut o mó v eis UIS diagram (detailed) Accelerator position (APP) sensor Battery Crankshaft position (CKP) sensor Engine control module (ECM) Engine control relay Engine coolant temperature (ECT) sensor Exhaust gas recirculation (EGR) solenoid Fuel cooler Fuel filter Unit injector Fuel lift pump Fuel lift pump relay Fuel pressure regulator Fuel tank Fuel temperature sensor Glow plug relay Glow plug Glow plug warning lamp Ignition switch Intake air temperature (IAT) sensor Malfunction indicator lamp (MIL) Manifold absolute pressure (MAP) sensor Mass air flow (MAF) sensor Turbocharger wastegate regulating valve Vehicle speed sensor (VSS)

71. Diesel fuel injection system – unit-pump injection systems One pump per cylinder ( unit-pump ), directly driven by engine camshaft Unit-pump connected to injector via short high-pressure line. For medium to heavy-duty diesel engines (up to 80 kW per cylinder) Fuel-injection pressures of up to 2,200 bar Injection quantity/timing Purely Mechanically-controlled ECU-controlled

72. 27 de outubro de 2016 | 70 Diesel fuel injection system – unit-pump injection systems System schematics (ECU-controlled system)

73. Sis t emas Aut o mó v eis Diesel fuel injection system – unit-pump injection systems Unit-pump and fuel injector detail

74. Diesel fuel injection system – common-rail systems High-pressure fuel accumulator feeds all injectors usually known as common-rail High pressure fuel pump feeds fuel rail pressure is independent of RPM ECU controls fuel pressure and injection quantity/timing First series-production systems Denso, 1995, heavy-duty trucks Hino Rising Ranger Bosch/Fiat, 1997, passenger cars Alfa Romeo 156 2.4 JTD Mercedes-Benz C 220 CDI

75. Diesel fuel injection system – common-rail systems Main components (high-pressure circuit) Damping case, fuel return High pressure accumulator Fuel Pressure sensor High pressure line (accumulator to injector) Fuel return line Injector High-pressure pump Pressure regulator (pump) High pressure line (to rail) Pressure regulator (rail)

76. eis Diesel fuel injection system – common-rail systems System diagram Feed pump (not in all systems) Filter Overflow valve Fuel return manifold High Pressure pump Pressure control valve (not in all systems) Rail pressure sensor Fuel rail Injectors ECU Fuel temperature sensor Other sensors

77. Diesel fuel injection system – common-rail systems Example of control diagram

78. Diesel fuel injection system – common-rail systems Main manufacturers Denso HP2, HP3, HP4 Bosch CRS1/CP1, CRS2/CP2, CRS3/CP3, CRS4/CP4 Delphi Multec/DFP6 Other Caterpillar Siemens

79. Diesel fuel injection system – common-rail systems Bosch CRS1/CP1

80. Diesel fuel injection system – common-rail systems Bosch CRS3/CP3 EDC16 – fuel circuits

81. Diesel fuel injection system – common-rail systems Bosch CRS3/CP3 EDC16 – components overview

82. Diesel fuel injection system – common-rail systems Bosch CRS3/CP3 EDC16 – electromechanical diagram

83. Diesel fuel injection system – common-rail systems Bosch CRS3/CP3 EDC16 – ECU input/output diagram

84. Diesel fuel injection system – common-rail systems Bosch CP3 – main components (V8) high-pressure pump, fuel rails, injectors and fuel lines

85. Diesel fuel injection system – common-rail systems Bosch CP3 – low-pressure circuit Feed pump Flow rate limiter throttle overflow valve Fuel metering unit (fuel pressure regulator) zero delivery throttle

86. Diesel fuel injection system – common-rail systems Bosch CP3 – high-pressure circuit Suction valves Plungers (B) High-pressure valves

87. Diesel fuel injection system – common-rail systems Bosch CP3 – high-pressure pump overview

88. de outubro de 2016 | 86 Diesel fuel injection system – common-rail systems Bosch CP3 – high-pressure pump front/side views

89. Diesel fuel injection system – common-rail systems Bosch CP3 – high-pressure pump component list Flange Shaft Polygonal ring Housing Gear pump Overflow valve Low-pressure inlet Fuel metering unit Backflow connector High-pressure connector Plunger Bucket Suction valve High-pressure valve (out to rail)

90. Diesel fuel injection system – common-rail systems Unit-Pump common rail systems ( by Delphi ) Low-cost, small engines (India market)

91. Fuel injectors Fuel injectors are important to improve engine performance/power reduce fuel consumption mitigate exhaust gas emissions Injector malfunctioning leads to: high exhaust emissions (particularly unburnt hydrocarbons) increased fuel consumption erratic idling poor cold starting engine knocking engine hesitation reduced engine horsepower

92. Fuel injectors Injectors can be classified according to: Type of ICE and fuel SI or CI Function (what are aimed at) single-point (indirect) injection, multi-point indirect injection, direct injection, cold-start injection Working principle (purelly) mechanical, electromagnetic, piezoelectric Nozzle type Single/multiple hole nozzle, pintle nozzle, pintaux nozzle

93. Fuel injectors Nozzle types

94. Fuel injectors Injector working principle Mechanical Electromagnetic Piezoelectric

95. Fuel injectors Injection has greatly evolved more fuel pressure multiple jets Leads to better fuel atomization less engine noise less exhaust emissions

96. Recommended references https://www.dieselnet.com/ http://www.appropedia.org/Engine_components http://www.trucktrend.com/how-to/expert-advice/0904dp-diesel-injection-pumps/ http://auto.howstuffworks.com/diesel.htm http://www.tb-training.co.uk/CIsys.htm http://www.slideshare.net/amgadradhihadi/common-rail-diesel-fuel-systems http://pt.slideshare.net/KamalVora1/dr-vora-ppt-chapter-6-crs http://www.walshcarlines.com/pdf/Impact%20of%20Diesel%20Fuel%20Injection%20SIAT%202005.pdf https://www.researchgate.net/publication/260643808_Particulate_emissions_from_dies el_engines_Correlation_between_engine_technology_and_emissions