Primer on Automobile Fuel Efficiency and Emissions - Pollution Probe

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Vehicle Weight, Safety and Fuel Efficiency The view that heavier automobiles are always a safer choice has persisted for many years, despite recent analyses of highway fatality statistics in the U.S. demonstrating this is not the case. Decades ago, safety was not a primary design feature of automobiles. Seatbelts were not mandated in Canadian cars until 1976 and vehicles of that era were not designed to strategically distribute the force of a collision to protect the occupants. All else held equal, in a collision between two vehicles of unequal weight, the heavier vehicle will decelerate more slowly. The change in momentum experienced by the occupants is thus greater in the lighter vehicle, which increases the potential for injury. Thus, heavier vehicles were safer for the occupants, but such vehicles imposed greater risk on occupants of other, lighter vehicles in the event of a collision (not to mention pedestrians, cyclists and others that share the road). COMBINED RISK ** The situation is different today. The materials that vehicles are built with vary from model to model; therefore, size is not always an accurate indication of weight. Engine and drivetrain technologies are also more diverse, so small vehicles are not always the most fuel efficient. The greatest change in modern vehicle design is in the priority placed on occupant safety. Vehicles today are much better equipped to protect their occupants in the event of a collision. Most vehicles incorporate structural components that are designed to collapse and absorb the GRAPH 3-1 Safety Risks of Vehicles with energy of an impact, which is complemented by passenger compartments designed to resist deformation. Together with passenger restraint systems, such High and Low Fuel Economy as seatbelts and airbags, raw weight is not necessarily (Source: Wenzel and Ross 2006) 250 the determining factor in survival rates for collisions. Recent studies (Wenzel & Ross, 2006, Joksch, 1998, 200 150 100 in a collision than some heavier, less fuel efficient vehicles – and in some cases the lighter car may be the Risk-to-others Ahmad & Greene, 2004) demonstrate that some more Risk-to-drivers fuel efficient vehicles present no higher risk of fatality safer choice (see Graph 3-1). The prevalent view today 50 is that reducing vehicle weight while maintaining vehicle 0 size (width and length) can help to reduce highway more fuel efficient models less efficient vehicle models fatalities. This thinking has informed policy in the U.S.; new federal fuel economy regulations in the U.S. do not promote vehicle downsizing, but do reward vehicle lightweighting as a strategy to comply with higher fuel efficiency performance. Lexus RS300* Honda CRV Ford Escape* Honda Civic* Chevy Suburban Hyundai Elantra Ford Focus Chevy Tahoe Ford Explorer Chevy Trailblazer Dodge Dakota Dodge Ram 1500 * Hybrid model available ** Combined risk includes the risks to own driver and to other drivers Ford F-150 Ford Ranger
Did you know? For every 10 per cent reduction in vehicle mass, fuel consumption can be reduced by 5 to 7 per cent. (roughly 540 kg from an average mid-sized sedan). For example, the Acura NSX sports car manufactured by Honda between 1990 and 2005 had a lightweight aluminum body, which made it 40 per cent lighter than a comparable steel body. One of the most fuel efficient cars ever massproduced was the Audi A2 (sold in Europe from 1999-2002), a small sedan seating five that incorporated an innovative, lightweight aluminum space frame design (a forerunner to one used in today’s Audi R8, named Canadian Car of the Year by the Automobile Journalists Association of Canada in 2008). Transport Canada road-tested the Audi A2 in Canada for two years and recorded an average fuel consumption performance of 2.7 L/100km. That’s roughly a quarter of the fuel consumed by the average Canadian vehicle. While these are higher-priced examples, they nonetheless illustrate that reducing a vehicle’s weight can make a big difference in fuel consumption. Audi A2. (Source: www.audi.com) Reducing Engine Size The size of an engine is a factor in its peak power output and fuel consumption. Engine size is measured by the total volume displaced by the pistons in the cylinders as they move from their furthest point up to their furthest point down. Thus, engine size is also referred to as displacement and is measured in litres or cubic inches. In general, the larger the engine and the more cylinders it has (smaller engines usually have four cylinders, larger engines have six or eight – or more), the greater its fuel consumption (see Table 3-1). Smaller engines tend to operate closer to their optimal efficiency levels under typical driving conditions, meaning more of the energy from the fuel is converted into work at the crankshaft, whereas in larger engines more of the available energy in the fuel consumed (under similar driving conditions) is lost to heat and friction. <strong>Primer</strong> on Automobile Fuel Efficiency & Emissions 44
Page 1 and 2: PRIMER ON AUTOMOBILE FUEL EFFICIENC
Page 3 and 4: POLLUTION PROBE’S PRIMER SERIES P
Page 5 and 6: JUNE 2009 Pollution Probe is please
Page 7 and 8: D R A F T C O P Y D R A F T C O P Y
Page 9 and 10: Chapter 5 BACKGROUND ON FUEL EFFICI
Page 11 and 12: CHAPTER 1 | EMISSIONS FROM AUTOMOBI
Page 13 and 14: ways to power automobiles, such as
Page 15 and 16: In the real world, however, combust
Page 17 and 18: TABLE 1-1, CONTINUED OXIDES OF NITR
Page 19 and 20: TABLE 1-1, CONTINUED OXIDES OF SULP
Page 21 and 22: This “enhanced greenhouse effect
Page 24 and 25: CHAPTER Chapter 2 TWO D R A F T C O
Page 26 and 27: BOX 2-1 Fuel economy improvements v
Page 28 and 29: Five Automobile Subsystems, continu
Page 30 and 31: Five Automobile Subsystems, continu
Page 32 and 33: % Energy Flow Within A Vehicle (val
Page 34 and 35: % % % % How an Internal Combustion
Page 36 and 37: The higher the compression ratio of
Page 38 and 39: Major forces on an automobile in mo
Page 40 and 41: Inertia To increase speed, the engi
Page 42 and 43: CHAPTER THREE INCREASING Chapter 3
Page 46 and 47: FIGURE 3-1 Engine Size: Power versu
Page 48 and 49: Turbocharging and Supercharging Mos
Page 50 and 51: Table 3-2: Engine Technology and Fu
Page 52 and 53: Gasoline versus Diesel engines: Gas
Page 54 and 55: Reducing Drivetrain losses The Tran
Page 56 and 57: call parasitic loads on the cranksh
Page 58: Hybrid Electric Vehicles Today, the
Page 61 and 62: Parallel Architecture Internal Comb
Page 63 and 64: these battery options is expected t
Page 65 and 66: CHAPTER 4 | WHAT YOU CAN DO TO MAXI
Page 67 and 68: A poorly operating Emission Control
Page 69 and 70: Table 4-2: Aerodynamics and Roof Ra
Page 71 and 72: Plan trips wisely. When doing erran
Page 73 and 74: Consider your fuel options. Unless
Page 76 and 77: Purchasing a Vehicle When it comes
Page 78 and 79: A fuel consumption gauge is an inst
Page 80 and 81: CHAPTER FIVE BACKGROUND ON FUEL EFF
Page 82 and 83: and heavy. On average, the 1974 mod
Page 84 and 85: Fuel Efficiency Trends As discussed
Page 86 and 87: Table 5-1: CAFC Targets CAFC Standa
Page 88 and 89: egulations have been implemented wi
Page 90 and 91: U.S Federal Tier 1 Emissions Standa
Page 92: Table 5-3: California LEV II Emissi
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CHAPTER 6 | WHAT IS BEING DONE BY G
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Table 6-1: Green Levy Tax Rates Com
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ONTARIO Sales Tax Rebate — People
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sideration that will force automake
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of about €5,000 (CA$8,400) for th
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CHAPTER 7 | WHAT NEEDS TO BE DONE E
Page 107 and 108:
EcoMobility for a Cleaner Environme
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This should also benefit automakers
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TORONTO OFFICE: 625 Church Street S
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