Automotive Systems course (Module 05) - Preheating Systems for vehicles with Internal Combustion...
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Transcript of Automotive Systems course (Module 05) - Preheating Systems for vehicles with Internal Combustion...
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ICE (pre)Heating Systems
Mário Alves ([email protected])
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Outline
• Classification of (pre)heating systems
• Combustion chamber preheating
• Intake air heating
• Fuel & exhaust system heating
• Glossary
• Recommended references
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Classification of (pre)heating systems
• Combustion chamber preheating
• Intake air heating
• Fuel & exhaust system heating
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Combustion chamber preheating
• In CI engines, air/fuel mix ignition results from compression and temperature • for cold engine (specially in cold weather), the inertial mass of
engine cylinders/block absorb the heat of compression, preventing ignition
• glow-plugs are used to aid the engine
• cranking (helps vaporizing the fuel)
• warming up (reduces smoke and engine knocking)
• Glow-plugs • long-shaped electric heaters
• reach ≈1000 ºC in a couple of seconds
• glow-plug tip pointed to
• pre-chamber indirect injection
• combustion chamber direct injection
http://www.eurotechmotors.com/lit-up-like-a-christmas-tree/
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Combustion chamber preheating
https://www.ngk.de/en/technology-in-detail/glow-plugs/glow-plugs-basic-principles/
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Combustion chamber preheating
https://www.quora.com/What-is-the-difference-between-direct-and-
indirect-fuel-injection
Glow-plug location in direct injection
Glow-plug location in indirect injection
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Combustion chamber preheating
• Glow-plug
• pencil-shaped device with heating element at tip
• Construction
• metal sheathing – metallic heating coil
• ceramic sheathing
http://www.ngkntk.co.uk/index.php/technical-centre/glow-plugs/
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Combustion chamber preheating
• Metal sheathed glow-plug
• glow tube filled with magnesium oxide powder:.
(electrical insulator, heat conductor and
vibration/impact absorber)
http://www.ngk.com.au/glow-plugs/technical-information/glow-plug-types
https://www.ngk.de/en/technology-in-detail/glow-plugs/design-of-a-glow-plug/design-of-a-metal-glow-plug/
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Combustion chamber preheating
• Ceramic (silicon nitrite) sheathed glow plug
• compact design, good thermal conductivity
• higher glow temperatures and faster heating
http://www.ngk.com.au/glow-plugs/technical-information/glow-plug-types
https://www.ngk.de/en/technology-in-detail/glow-plugs/design-of-a-glow-plug/design-of-a-ceramic-glow-plug/
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Combustion chamber preheating
• States of a glow-plug
• <80s several tens of seconds to reach max temperature
• >80s few seconds to reach max temperature
https://www.ngk.de/en/technology-in-detail/glow-plugs/glow-plugs-basic-principles/
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Combustion chamber preheating
• Self-regulating glow-plugs
• auto-protection against overheating, by
limiting the current from the battery
• why? to prevent glow-plugs from burning out
• due to the heating of the glow-plug itself
• due to sudden rise in charging system
voltage (when alternator starts
generating)
• due to the heating of the engine warming-
up
• regulator coil
• resistance grows with temperature
• inserted in series with the heating coil
http://www.google.gg/patents/US5132516
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Combustion chamber preheating
• Self-regulating glow-plug (example by Bosch)
http://www.ebay.com/itm/4-x-BOSCH-Duraterm-Glow-Plug-SET-TOYOTA-
1AZ-FSE-2RZ-FE-2KD-FTV-KZ-Diesel-Engines-/171077062129
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Combustion chamber preheating
• Self-regulating glow-plug (example by NGK)
http://www.ngk.com.au/glow-plugs/technical-information/glow-plug-types
https://www.ngkntk.in/ngk-glow-plugs/
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Combustion chamber preheating
• Self-regulating glow-plug (example by Brisk)
http://www.brisk.biz/catalogues/glow-plugs/tube-glow-plugs-for-diesel-engines
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Combustion chamber preheating
• Glow-plug control
• “old” systems used dedicated hardware
• current systems are controlled by the engine ECU
• may feature a separated glow-plug controller/power unit
• Preheating phases
• pre-glowing
• starts at ignition ON (until engine cranking)
• glow plugs at full power
• cranking (starting)
• starts at ignition STA (until cranking ends)
• glow-plugs at full power
• after-glowing
• starts when cranking ends (engine running autonomously)
• for improved combustion, reduced exhaust gas emissions and smoother engine operation
• duration may depend on coolant temperature
http://www.brisk.biz/catalogues/glow-plugs/tube-glow-plugs-for-diesel-engines
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Combustion chamber preheating
• Glow-plug control (typical timing/state diagram)
http://www.brisk.biz/catalogues/glow-plugs/tube-glow-plugs-for-diesel-engines
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Combustion chamber preheating
• Glow-plug control
• Inputs (sensors)
• ignition switch position (OFF, ON, STA)
• coolant (or oil) temperature (for controlling glow timing)
• alternator charging signal (for signaling engine running)
• (glow plug current sensor (via low resistor voltage))
• (intake air pressure)
• (glow-plug voltage)
• Outputs (actuators)
• relay(s) (or electronic switches) glow plugs (1 per cylinder)
• main relay (pre-glow)
• secondary relay (after-glow)
• glow plugs indicator light (instrument panel)
• (intake air preheater – for heavy-duty engines)
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Combustion chamber preheating
• Glow-plug control
• relay(s) glow plugs (1 per cylinder)
• main relay (pre-glow) full power/voltage
• secondary relay (after-glow) reduced power (voltage
divider)
http://www.tb-training.co.uk/MarineE07.html
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Combustion chamber preheating
http://www.moranbahweather.com/toyota/hilux/repair2/html/frame_rm000000wrb001x.html
• Glow-plug control (example 1)
http://www.moranbahweather.com/toyota/hilux/repair2/html/frame_rm000000w0b003x.html
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Combustion chamber preheating
• Glow-plug control (example 2)
http://forum.ih8mud.com/threads/12v-super-glow-experts.537246/
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Combustion chamber preheating
• Glow-plug control (example 3)
http://www.ford-trucks.com/forums/1034500-cold-start-issue.html
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Combustion chamber preheating
• Glow-plug control
(example 4)
http://www.moranbahweather.com/toyota/hilux/repair2/html/frame_rm000000wrb001x.html
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Intake air heating
• Heating intake air (specially in cold weather conditions)
• improves engine cranking
• smoothens cold-start engine operation (warm-up phase)
• helps reducing exhaust gas emissions (specially HC)
• Available technologies
• filament glow plugs
• simple to apply, proven design, long service intervals
• heating flange
• fast heating up, long life, very effective lowering emissions
• flame (combustion) start systems
• high heating, low electrical energy consumption, mitigates
white smoke
http://www.brisk.biz/catalogues/glow-plugs/tube-glow-plugs-for-diesel-engines
http://www.phillipsandtemro.com/heating_technology/air_intake_heaters.asp
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Intake air heating
• Flame Start Systems (based on a “flame” glow plug)
• once the heating temperature has been reached, fuel enters the evaporator in the flame glow plug via a solenoid valve
• then, a flame is produced that heats the intake air
• Example (by BERU) 1. Electrical connection
2. Insulation
3. Plug housing
4. Fuel connection
5. Fuel feed
6. Metering device
7. Evaporator sieve
8. Evaporator pipe
9. Electrically heated heater rod
10. Protective tube
11. Flame sleeve
http://beru.federalmogul.com/diesel-cold-start-technology/product-
description/diesel-cold-start-technology
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Intake air heating
• Heating flange systems
• electrical heating output is transmitted to the ambient or through-
flowing air via a heating coil
• heating coil consists of highly corrosion-resistant flat wires
• special form of the heating coil add to its vibration resistance,
guaranteeing play-free expansion during temperature increase
• Example (by DBK)
• voltage range: 12V / 24V
• power range: up to 7 kW
• Heating time: 3 s
http://www.dbk-group.com/us/195/dbk-solutions/automotive-%2B-power-applications/intake-air-preheating.html
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Intake air heating
• Filament glow plug
• for older heavy-duty diesel vehicles (tractors, tow trucks and
construction machines), as well as stationary engines
• wire filament is the heating element
https://www.rpmoutlet.com/diaafe222a.htm
http://www.brisk.biz/catalogues/glow-plugs/intake-air-heaters
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Intake air heating
• Example (2000 Ford F250/350 series)
http://www.justanswer.com/ford/4epb5-ford-f350-superduty-pickup-4x4-
2000-ford-f350-7-3-diesel.html
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Fuel & exhaust system heating
• Heating Diesel fuel may be needed because
• at low temperatures, diesel fuel forms paraffin crystals (suspended in the liquid)
• as the concentration increases, the fuel filter may become blocked
• the engine could stall (diesel waxing)
• so fuel is preheated in the fuel line, where it melts the paraffin crystals before they reach the primary filter
• Types
• in-line fuel heaters
• found in most Diesel vehicles, usually located upstream (attached to) the main filter
• in-tank fuel heaters
• only in heavy-duty vehicles and extreme weather conditions
http://www.brisk.biz/catalogues/glow-plugs/tube-glow-plugs-for-diesel-engines
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Fuel & exhaust system heating
• In-line fuel heaters
• Electrical heater
• in the fuel filter
• inside fuel line
http://www.arctic-fox.com/products/arctic-fox174-in-tank-fuel-warmers
http://www.autozone.com/repairguides/Ford-Tempo-Topaz-1984-1994-Repair-Guide/ROUTINE-MAINTENANCE/Fuel-Filter/_/P-0900c1528005d3e0
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Fuel & exhaust system heating
• In-tank fuel heaters
• maintains fuel temperature levels recommended by engine
manufacturers for electronic fuel systems
• uses coolant fluid heat to warm-up the fuel
• optional integrated mechanical thermostat to by-pass fuel
warming loop when fuel temperature reaches optimum
http://www.arctic-fox.com/products/arctic-fox174-in-tank-fuel-warmers
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Fuel & exhaust system heating
• Diesel Exhaust Fluid (DEF, aka as AdBlue)
• solution composed of urea (32,5%) and deionized water (67.5%)
• used in Selective Catalytic Reduction (SCR) systems to reduce
NOx concentration in Diesel exhaust emissions
• this solution (adBlue; a consumable) must be heated and injected
into the exhaust system
• DEF is a consumable (2% of fuel consumption), thus vehicles
using these catalytic converters have a specific tank for DEF
• DEF tank/injector heaters
• DEF cannot freeze (< 11º C; ideal = -5º to 30º C)
• heating for the DEF tank and supply lines must be provided
• DEF heating can be electrical and/or engine coolant-based
http://www.arctic-fox.com/products/arctic-fox174-in-tank-fuel-warmers
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Fuel & exhaust system heating
• DEF heating (Example 1 – Isuzu)
http://collision.enterprise.alldata.com/online2help/techRef/Diesel_Car_and_Truck_Visual_In
spections/Isuzu.htm
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Fuel & exhaust system heating
• DEF heating (Example 2 – Bosch)
http://www.technology.matthey.com/article/59/3/221-232/
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Fuel & exhaust system heating
• DEF heating (Example 3 – Delphi)
http://www.delphi.com/manufacturers/auto/powertrain/diesel/em-tech/scrds
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Fuel & exhaust system heating
• SCR heating
• SCR needs exhaust gas temperature > 200°C to ensure a complete
decomposition and hydrolysis of urea to ammonia
• typically depends on engine/exhaust gas temperatures to reach its
operating temperature
• electrically heated catalyst minimizes cold start emissions by
reducing SCR heating time: Emicat
http://www.emitec.com/en/technology/catalyst-substrates/emicat/
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Fuel & exhaust system heating
• Emicat
http://www.car-engineer.com/emitecs-e-scr-system-for-nox-reduction/
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Fuel & exhaust system heating
• Oxygen sensors
• oxygen (aka O2 or lambda) sensors monitor the amount of
unburned oxygen is in the exhaust system
• informs ECU about (burned) A/F mixture oxygen content – rich
(less oxygen) or lean (more oxygen)
• currently two O2 sensors per exhaust manifold (upstream &
downstream the catalyst) for testing catalyst malfunctioning
• O2 sensors preheating
• O2 sensors only operate above 600º C
• cold-start A/F mixture is computed without
feedback from O2 sensors (open-loop)
• electrical heating helps reaching
operating temperature more quickly
http://www.autocodes.com/articles/oxygen_sensor_location.php
https://www.volvoclub.org.uk/faq/EngineSensors.html
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Fuel & exhaust system heating
• O2 sensors components/wiring
• unheated: 1-2 wires (obsolete)
• heated: 3-4 wires
http://www.autozone.com/repairguides/Acura-Coupes-and-Sedans-1994-2000-Repair-Information/Electronic-Engine-Controls/Oxygen-Sensor/_/P-0900c1528008be6b
http://www.lambdapower.co.uk/TechNotes/Tech-6.asp
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Glossary (English/Portuguese)
• …
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Recommended references
• https://aa-boschap-
uk.resource.bosch.com/media/parts/engine_systems__auto_parts_1/diesel__engine_syst
ems_1/glow_plugs/pia_glow_plugs_en_58333.pdf
• https://suw.biblos.pk.edu.pl/resources/i9/i9/i4/r994/IdziorM_ProblemsStarting.pdf
• http://www.beru.com/download/produkte/TI01_en.pdf
• http://emissions.borgwarner.com/download/produkte/whitepaper_iss_en.pdf
• M. N. Azpiazu, C. Bustamante, J. M. Morquillasz, “Effect of air preheating on
automotive emissions”, Springer journal of Water, Air, and Soil Pollution, Volume 51,
Issue 3, June 1990, pp 231-237. DOI: 10.1007/BF00158221
• http://www.lambdapower.co.uk/
• …