1 / 78

OBJECTIVES

OBJECTIVES. After studying Chapter 10, the reader will be able to: Describe how the proper grade of gasoline affects engine performance. List gasoline purchasing hints. Discuss how volatility affects driveability. Explain how oxygenated fuels can reduce CO exhaust emissions.

terah
Download Presentation

OBJECTIVES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. OBJECTIVES After studying Chapter 10, the reader will be able to: • Describe how the proper grade of gasoline affects engine performance. • List gasoline purchasing hints. • Discuss how volatility affects driveability. • Explain how oxygenated fuels can reduce CO exhaust emissions. • Discuss the advantages and disadvantages of various alternative fuels.

  2. AUTOMOTIVE FUEL REFINING • As it comes out of the ground, petroleum (meaning “rock oil”) crude can be as thin and light colored as apple cider or as thick and black as melted tar. • Thin crude oil has a high American Petroleum • Institute (API) gravity, and therefore is called highgravity crude, and thick crude oil is called low-gravity crude. • Processes • Distillation • Cracking • Shipping

  3. AUTOMOTIVE FUEL REFINING FIGURE 10-1 The crude oil refining process showing most of the major steps and processes.

  4. GASOLINE • Gasoline is a term used to describe a complex mixture of various hydrocarbons refined from crude petroleum oil for use as a fuel in spark-ignition engines. • Most gasoline is “blended” to meet the needs of the local climates and altitudes.

  5. VOLATILITY • Volatility describes how easily the gasoline evaporates (forms a vapor). • Winter Blend • Summer Blend • Volatility Problems

  6. WHAT IS A CALIFORNIA GAS CAN? FIGURE 10-2 A gas can that meets the California Resources Board (CARB) approval uses a spring-loaded sealed nozzle that eliminates gasoline spillage and leaks into the atmosphere.

  7. VOLATILITY FIGURE 10-3 A gasoline testing kit. Included is an insulated container where water at 100°F is used to heat a container holding a small sample of gasoline. The reading on the pressure gauge is the Reid vapor pressure (RVP).

  8. DISTILLATION CURVE FIGURE 10-4 A typical distillation curve. Heavier molecules evaporate at higher temperatures and contain more heat energy for power, whereas the lighter molecules evaporate easier for starting.

  9. DRIVEABILITY INDEX • A distillation curve shows how much of a gasoline evaporates at what temperature range. • To predict cold-weather driveability, an index was created called the driveability index, also called the distillation index, and abbreviated DI.

  10. NORMAL AND ABNORMAL COMBUSTION • The octane rating of gasoline is the measure of its antiknock properties. • Engine knock (also called detonation, spark knock, or ping) is a metallic noise an engine makes, usually during acceleration, resulting from abnormal or uncontrolled combustion inside the cylinder. FIGURE 10-5 Normal combustion is a smooth, controlled burning of the air-fuel mixture.

  11. NORMAL AND ABNORMAL COMBUSTION FIGURE 10-6 Detonation is a secondary ignition of the air-fuel mixture.It is also called spark knock or pinging.

  12. OCTANE RATING • The two basic methods used to rate gasoline for antiknock properties (octane rating) are the research method and the motor method. • The pump octane is called the antiknock index (AKI).

  13. GASOLINE GRADES AND OCTANE NUMBER • The posted octane rating on gasoline pumps is the rating achieved by the average of the research and the motor methods. FIGURE 10-7 A typical fuel pump showing regular (87 octane), midgrade (89 octane), and premium (92 octane). These ratings can vary with brand as well as in different parts of the country, especially in high-altitude areas where the ratings are lower.

  14. OCTANE IMPROVERS • Octane improvers (enhancers) can be grouped into three broad categories: • Aromatic hydrocarbons (hydrocarbons containing the benzene ring) such as xylene and toluene • Alcohols such as ethanol (ethyl alcohol), methanol (methyl alcohol), and tertiary butyl alcohol (TBA) • Metallic compounds such as methylcyclopentadienyl manganese tricarbonyl (MMT)

  15. OXYGENATED FUELS • Oxygenated fuels contain oxygen in the molecule of the fuel itself. • Oxygenated fuels are commonly used in high-altitude areas to reduce carbon monoxide (CO) emissions. • Methyl Tertiary Butyl Ether (MTBE) • Tertiary-Amyl Methyl Ether • Ethyl Tertiary Butyl Ether • Ethanol • Methanol

  16. OXYGENATED FUELS FIGURE 10-8 This fuel pump indicates that the gasoline is blended with 10% ethanol (ethyl alcohol) and can be used in any gasoline vehicle. E85 contains 85% ethanol and can only be used in vehicles specifically designed to use it.

  17. OXYGENATED FUELS FIGURE 10-9 A container with gasoline containing alcohol. Notice the separation line where the alcohol/water mixture separated from the gasoline and sank to the bottom.

  18. ALCOHOL ADDITIVES—ADVANTAGES AND DISADVANTAGES • The advantages and disadvantages of using alcohol as an additive to gasoline can be summarized as follows: • Advantages • Alcohol absorbs moisture in the fuel tank. • Ten percent alcohol added to gasoline raises the octane rating, (R M) 2, by three points. • Alcohol cleans the fuel system. • Alcohol reduces CO emissions because it contains oxygen.

  19. ALCOHOL ADDITIVES—ADVANTAGES AND DISADVANTAGES • Disadvantages • The use of alcohol can result in the clogging of fuel filters with dirt and other debris cleaned from the fuel tank, pump, and lines. • Alcohol raises the volatility of fuel about 0.5 PSI; this can cause hot-weather driveability problems. • Alcohol reduces the heat content of the resulting fuel mixture (it has about one-half of the energy content of gasoline)—60,000 to 75,000 British thermal units (BTUs) per gallon for alcohol versus about 130,000 BTUs per gallon for gasoline. • Alcohol absorbs water and then separates from the gasoline, especially as temperature drops.

  20. TESTING GASOLINE FOR ALCOHOL CONTENT • Take the following steps when testing gasoline for alcohol content. • Pour suspect gasoline into a small clean beaker or glass container. • Carefully fill the graduated cylinder to the 10-mL mark. • Add 2 mL of water to the graduated cylinder by counting the number of drops from an eyedropper. • Put the stopper in the cylinder and shake vigorously for 1 minute. Relieve built-up pressure by occasionally removing the stopper. • Place the cylinder on a flat surface and let it stand for 2 minutes. • Take a reading near the bottom of the cylinder at the boundary between the two liquids. • For percent of alcohol in gasoline, subtract 2 from the reading and multiply by 10.

  21. COMBUSTION CHEMISTRY • The combustion process involves the chemical combination of oxygen (O2) from the air (about 21% of the atmosphere) with the hydrogen and carbon from the fuel.

  22. AIR-FUEL RATIOS • The air-fuel ratio is the proportion by weight of air and gasoline that the injection system mixes as needed for engine combustion. FIGURE 10-10 An engine will not run if the air-fuel mixture is either too rich or too lean.

  23. AIR-FUEL RATIOS • Stoichiometric Air-Fuel Ratio • Stoichiometric Air-Fuel Ratio for Various Fuels FIGURE 10-11 With a three-way catalytic converter, emission control is most efficient with an air-fuel ratio between 14.65:1 and 14.75:1.

  24. HIGH-ALTITUDE OCTANE REQUIREMENTS • As the altitude increases, atmospheric pressure drops. • The air is less dense because a pound of air takes more volume. • The octane rating of fuel does not need to be as high because the engine cannot take in as much air. FIGURE 10-12 Photo of gasoline pump taken in a high-altitude area. Note the lower-than-normal octane ratings. The “ethanol” sticker reads that all grades contain 10% ethanol from November 1 through February 28 each year to help reduce CO exhaust emissions.

  25. REFORMULATED GASOLINE • Reformulated gasoline (RFG) is manufactured by refiners to help reduce emissions. • The gasoline refiners reformulate gasoline by using additives that contain at least 2% oxygen by weight and reducing the additive benzene to a maximum of 1% by volume. • Two other major changes done at the refineries are as follows: • Reduce light compounds. • Reduce heavy compounds.

  26. WHAT IS “TOP-TIER”GASOLINE? FIGURE 10-13 The gas cap on a Ford vehicle notes that BP fuel is recommended.

  27. GENERAL GASOLINE RECOMMENDATIONS • The fuel used by an engine is a major expense in the operation cost of the vehicle. • The proper operation of the engine depends on clean fuel of the proper octane rating and vapor pressure for the atmospheric conditions.

  28. GENERAL GASOLINE RECOMMENDATIONS FIGURE 10-14 Many gasoline service stations have signs posted warning customers to place plastic fuel containers on the ground while filling. If placed in a trunk or pickup truck bed equipped with a plastic liner, static electricity could build up during fueling and discharge from the container to the metal nozzle, creating a spark and possible explosion. Some service stations have warning signs not to use cell phones while fueling to help avoid the possibility of an accidental spark creating a fire hazard.

  29. ALTERNATIVE FUELS FIGURE 10-15 Some retail stations offer a variety of fuel choices, such as this station in Ohio where biodiesel, E10, and E85 are available.

  30. ALTERNATIVE FUELS • Ethanol • E85 • Flex Fuel Vehicles • How to Read a Vehicle Identification Number • Methanol • M85 • Propane • Compressed Natural Gas (CNG)

  31. ALTERNATIVE FUELS FIGURE 10-16 The ethanol molecule showing two carbon atoms, six hydrogen atoms, and one oxygen atom.

  32. ALTERNATIVE FUELS FIGURE 10-17 A vehicle emission control information (VECI) sticker on a flexible fuel vehicle indicating the percentage of ethanol with which it is able to operate.

  33. ALTERNATIVE FUELS FIGURE 10-18 The location of the variable fuel sensor can vary, depending on the make and model of vehicle, but it is always in the fuel line between the fuel tank and the fuel injectors.

  34. ALTERNATIVE FUELS FIGURE 10-19 A cutaway view of a typical variable fuel sensor.

  35. ALTERNATIVE FUELS FIGURE 10-20 A pump for E85 (85% ethanol and 15% gasoline). There are few, if any, of these pumps in many states.

  36. ALTERNATIVE FUELS FIGURE 10-21 The molecular structure of methanol showing the one carbon atom, four hydrogen atoms, and one oxygen atom.

  37. ALTERNATIVE FUELS FIGURE 10-22 Sign on methanol pump shows that methyl alcohol is a poison and can cause skin irritation and other personal injury. Methanol is used in industry as well as a fuel source.

  38. ALTERNATIVE FUELS FIGURE 10-23 Propane fuel storage tank in the trunk of a Ford taxi.

  39. ALTERNATIVE FUELS FIGURE 10-24 The blue sticker on the rear of this vehicle indicates that it is designed to use compressed natural gas.

  40. ALTERNATIVE FUELS FIGURE 10-25 The fuel injectors used on this Honda Civic GX CNG engine are designed to flow gaseous fuel instead of liquid fuel and cannot be interchanged with any other type of injector.

  41. ALTERNATIVE FUELS FIGURE 10-26 A CNG storage tank from a Honda Civic GX shown with the fixture used to support it while it is being removed or installed in the vehicle. Honda specifies that three technicians be used to remove or install the tank through the rear door of the vehicle due to the size and weight of the tank.

  42. P-SERIES FUELS • P-series alternative fuel is patented by Princeton University and is a non-petroleum-based fuel suitable for use in flexible fuel vehicles or any vehicle designed to operate on E85 (85% ethanol, 15% gasoline). • P-series fuels are blends of the following: • Ethanol (ethyl alcohol) • Methyltetrahydrofuron, abbreviated MTHF • Natural gas liquids, such as pentanes • Butane

  43. DIESEL FUEL • The fuel in a diesel engine is not ignited with a spark, but is ignited by the heat generated by high compression. • All diesel fuel must be clean, be able to flow at low temperatures, and be of the proper cetane rating. • Cleanliness. • Low-temperature fluidity. • Cetane number

  44. DIESEL FUEL • Diesel Fuel Specific Gravity Testing • Diesel Fuel Heaters • Ultra-Low-Sulfur Diesel Fuel FIGURE 10-27 Testing the API viscosity of a diesel fuel sample using a hydrometer.

  45. DIESEL FUEL FIGURE 10-28 A pump decal indicating that the diesel fuel is ultra-low-sulfur diesel (ULSD) and must be used in 2007 and newer diesel vehicles.

  46. BIODIESEL • Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant greases. • Biodiesel is safe, biodegradable, and reduces serious air pollutants such as particulate matter (PM), carbon monoxide, and hydrocarbons.

  47. BIODIESEL FIGURE 10-29 Biodiesel is available at few locations.

  48. E-DIESEL FUEL • E-diesel, also called diesohol outside of the United States, is standard No. 2 diesel fuel that contains up to 15% ethanol. • While E-diesel can have up to 15% ethanol by volume, typical blend levels are from 8% to 10%. • Cetane Rating

  49. SYNTHETIC FUELS • Synthetic fuels were first developed using the Fischer-Tropsch method and have been in use since the 1920s to convert coal, natural gas, and other fossil fuel products into a fuel that is high in quality and clean-burning. • Coal to Liquid (CTL) • Methanol to Gasoline • Future of Synthetic Fuels

More Related