CH35 fuels and other energy sources STUDENT VERSION rev

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Chapter 35

Fuels and Other Energy Sources

• Separates the hydrocarbons into useful

substances by fractional distillation

• Very few of the fractions are usable without treating and cleaning

• Some fractions are altered to be used for a specific application

• Major factors affecting fuel performance:

– Antiknock quality, volatility, sulfur content, and deposit control

Antiknock Quality

• Represented by the octane number

• Two methods used to determine octane

number:

– Motor octane number (MON)

– Research octane number (RON)

• A test sample of fuel is used in a laboratory engine

Factors That Affect

• Air inlet temperature

• Combustion chamber shape

• Octane number

• Readily evaporates so gas vapor adequately mixes with air for combustion

• Gasoline volatility affects:

– Cold starting and warm-up

– High altitude operation

– Crankcase oil dilution

Basic Gasoline Additives

• Anti-icing or deicer

• Metal deactivators and rust inhibitors

• Gum or oxidation inhibitors

Gasoline Quality Testing

• Reid Vapor Pressure

– Measures the volatility of the fuel.

– Affects how an engine runs in cold weather.

Alternatives to Gasoline

• Renewable fuels are derived from non-fossil sources

• Biomass fuels can be used in internal

combustion engines and tend to be neutral

carbon-• Ethanol and methanol fuels, such as E85

• Already used as oxygenates in gasoline

• High quality, low cost, high octane fuel

• Burns cleaner than gasoline

• Produced from corn, sugar cane, grains, and other biomass waste

• Commonly used in E10 and E85 blends

• Most vehicles can use E10

• A clean burning alcohol fuel

• Often made from natural gas but can be made from coal and biomass

• Used in blends of M15 and M85

• Blending with gasoline improves cold weather starting ability

Flexible Fuel Vehicles (FFV)

• Can use ethanol and/or gasoline or a

mixture of the two

• Stored in the same fuel tank

• Some vehicles use a sensor that detects the fuel blend

• Others use the HO2S readings to virtually determine fuel composition

Propane (LP-gas)

• Liquefied petroleum gas is used by many

fleets

• Stored as a liquid at about 200 psi

• Produces less HC, CO2, and CO

• Slight engine power reduction from reduced cylinder filling

Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG)

• Abundant and less expensive than gasoline

• Clean burning with 25% less CO2 emitted

• Stored at 2400, 3000, or 3600 psi

• Requires large storage tanks

• LNG requires less space but must be stored and dispensed at very low temperatures

• Can be extracted from many sources

• Currently has a negative energy balance

• Liquefied hydrogen stored at -423ºF (-253ºC)

• Hydrogen fuel engines typically produce less power

• Very little infrastructure

Diesel Fuel

• Has about 15% more energy than gasoline

• Small, high speed diesel engines require high quality, high volatility fuel

• Diesel volatility measured by a cetane

rating

• Two grades of diesel fuel, Number 1 and 2

• Number 2 is most popular and available

Diesel Fuel (cont’d)

• Is a high sulfur content fuel

• Diesel engines emit particulates, called soot

• High combustion temperatures produce

high NOx emissions

• Diesel fuel prone to waxing or solidifying in cold weather

Low Sulfur Diesel Fuel

• Available due to mandates

• Previous standard allowed up to 500 PPM

• New standard is 15 PPM

• Allows diesels to emit less NOx, soot, and other sulfur compounds

Electric Vehicles (EVs)

• Used in manufacturing, shipping, and other industrial plants and on golf courses

• Electric motors powered by batteries

• Batteries must be recharged

• EVs emit zero emissions but are responsible for the pollution generated to produce the electricity to charge the batteries

Hybrid Electric Vehicles (HEVs)

• Combines two or more sources of power

• Current HEVs use an internal combustion engine and one or more electric motors

Series Hybrids

• The engine is used to drive a generator that charges the battery

• The battery powers the electric motor

• The computer monitors battery voltage and starts the engine as needed

• No series hybrids in production at this time

Parallel Hybrids

• The engine may power the vehicle and/or the generator

• Driving conditions and battery power

determine if either the engine or motor or both are used to propel the vehicle

• Since the engine can power the generator, these are also called series-parallel hybrids

Hybrid Vehicle Designs (cont’d)

• A full hybrid can run on just the engine or

just the batteries:

– Toyota Prius, Ford Escape, Honda Civic

• An assist hybrid cannot be power by the

• Consume less fuel

• Far fewer emissions due to smaller and more efficient engine and stop/start technology

• Many accessories and systems are

electrically operated which reduces fuel use

• Voltage depends on the vehicle, the system, and manufacturer

• Can range from 42 – 330 volts

• Most hybrids have a 12 volt battery for

conventional electrical items

• Most hybrid electronics are housed in a air

or water cooled assembly

• May also contain an inverter, DC-DC

converter, boost converter, and air

conditioning converter

• An inverter converts high DC voltage to high AC voltage

Belt Alternator Starter (BAS)

• Replaces traditional starter and generator

• Capable of stop/start, regenerative braking, and high-voltage generation

• May offer a small amount of engine assist

Integrated Starter Alternator Damper

• Replaces starter, generator, and flywheel

• Uses a compact AC induction motor

• Typically housed in bell housing

Honda’s Integrated Motor Assist System

Power-Split System

• Used by many series-parallel hybrids

• Instantaneously switches power sources

• Functions as a continuously variable

transaxle

• Does not use a torque converter or clutch

• Comprised of a planetary gear set and two electric motors

Two-Mode Transmission

• Uses two planetary gear sets and two electric motors:

– Results in a continuously variable transmission

• One operating mode is during low speed and low load

• The second mode is during highway cruising speeds

Plug-In Hybrid Electric Vehicles

(PHEVs)

• Full hybrids with larger batteries and can

recharge from the electric power grid

• Can charge overnight on standard 120 volt outlet

• Typical range on battery power alone is

about 60 miles before the gas engine starts

Hydraulic Hybrids

• Energy is stored in tanks of hydraulic fluid under pressure

• Stores energy when braking and uses it

when accelerating from a stop

• Also used to slow the vehicle for stopping

• May allow for 60 – 70% fuel savings in

large vehicles

Hybrid Service

• Hybrids use very high voltages

• HV cables covered in orange

• Refer to service procedures for depowering

HV system before all service work

• A/C, engine, transmission, and bodywork require work around the HV system

Maintenance and Service

• Non-hybrid components maintained and serviced in same way as conventional

vehicles.

• Awareness and understanding of the

stop/start feature necessary for safety

reasons.

• If not shut down correctly, the engine can start on its own.

Toyota Prius Ready Light

• HEVs have unique systems that require

special tools and procedures

• Some hybrids allow the disabling of the

hybrid electric drive system for diagnosis

• A manufacturers scan tool may be necessary

to provide complete diagnostic access

Fuel Cell Electric Vehicles

• FCEVs have electric motors

• A fuel cell generates electricity for the

motor and/or battery

• May use hydrogen or other fuel as the

energy source

• Pure water and heat are the only emissions