Background information Fuel Economy

2. Background information

1. Fuel Economy

Fuel consumption is the mathematical reciprocal of fuel economy. It is a measure of the amount of fuel consumed covering a given distance. It is measured in liters per 100 km in Europe and most of the world. In the United States it is measured in gallons per 100 miles. Being the reciprocal of fuel economy necessarily entails that for fuel consumption the relation. This in turn renders more instrumental in communicating the fuel savings, from improving fuel economy, in absolute terms to lay consumers. This is because the amount of fuel saved in improving fuel economy in the lower ranges of mpg is significantly higher than those at the higher ranges. Hence the benefits accrued from improving the fuel consumption of vehicles become more comprehensible to the average consumer.

2. Factors Affecting Fuel/Consumption Economy

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  Engine: The engine output power varies with its torque and speed. For each engine there is three dimensional curves plotting the output power against both Torque and speed. From this curve an optimum zone is located where the engine’s energy efficiency is maximized. In reality the vehicles runs through various driving ranges and modes at points outside the energy efficient zone. Using turbo charging, smaller engines all drive engine towards operation at the maximum efficiency zone (Institute of Mechanical engineers, 2011).
  
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    Combustion interval: short combustion interval allows for more of the generated heat to be used in driving the pistons
    
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    Higher compression ratio and optimized exhaust valve opening: Compression ratio is the volume between the volumes of the combustion chamber when the cylinder is at the bottom stroke to that when the cylinder is at top stroke. Better control of exhaust valve opening improves the energy efficiency of engine (Institute of Mechanical Engineers, 2011).
    
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  Pump losses: The pump losses result from pressure gradients along the piston, so it is the extra work required to suck air in and out of inlets (Chiaberge, 2011).
  
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  Friction losses: Friction losses result from piston and crank shaft mechanical connections. Improving precision of cylinder dimensions minimizes piston friction losses. Crank shaft bearing design and features have a straightforward impact on the associated friction losses (Institute of Mechanical engineers, 2011).
  
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  Oil and coolant pumps: following the wide-spread recommendations for reducing energy consumption of pumps are applicable for automotive engines.
  
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  Power steering: using electric drives for power steering reduces fuel consumption
  
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  Aerodynamics: air resistance to a vehicle’s traction, termed drag force is dependent on a factor called the drag coefficient. Reducing drag coefficient reduces fuel consumption
  
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  Tire resistance: the mass of the car putting pressure on tires leads to energy losses. This resistance is a function of tire design and air pressure. Design options that reduce tire resistance may weigh on safety and levels of wear and tear. Optimum trade-offs must be reached.
  
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  Transmission terrain: increasing the number of gear ratios reduces the losses in the transmission terrain. Several transmission technologies, such as planetary (differential gearboxes) and dual-clutch transmission, are commercially available to date
  
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  Stroke-To-Bore Ratio: This is the ratio between the length of the stroke and the diameter of the cylinder. As the stroke to bore ratio increases, air into the cylinder travels a longer distance reducing losses. As stroke to bore ratio decreases the surface area of piston decreases which leads to lesser friction losses for the crankshaft bearings (Institute of mechanical Engineers, 2011)
  
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  Number of balancing shafts: Those are shafts used for countering the vibration effects of cylinders. They have weight and inertia which consume energy thus reducing efficiency. Different engine classes use different number of balancing shafts (Stone, 1999).
  
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  Vehicle Weight: Vehicle mass has a profound impact on vehicle’s fuel consumption. Replacing steel with the lighter aluminum in alternative body structures, such as space frame is an approach. Another is the use of composite and carbon fiber materials which can be introduced into the mainstream body design. A combination of material availability, cost consideration and a downgrade of structural performance in aluminum based structures limit these approaches. Another less radical approach involves using thinner steel, sandwiched steel (layers of aluminum and steel), or new steel designs. The downside of the said conventional approaches is jeopardizing stiffness, or increased costs (Institute of Mechanical Engineers, 2011).
  
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  Fuel: The energy content per liter of diesel is higher than petrol and accordingly have a lower fuel consumption. Diesel’s carbon content is higher and so it emits more greenhouse gases on per liter basis. However, the lower fuel consumption leads to diesel fuelled vehicles, generally, emitting less greenhouse gases than petrol fuelled ones on kilometer basis.
  

3. Fuel Economy Standards

In response, fuel economy standards have been on debate, being variably adopted by different nations and transnational bodies, since the oil crisis of the seventies.

The European Union has set its fuel consumption/economy standards where manufacturers have to meet average fuel economy levels for their entire fleets (GFEI, 2014). The assigned value to each manufacturer is calculated on the basis of the mass of a vehicle giving manufacturers a level of flexibility to increase and decrease the fuel economy of their different models. It also allows higher values for heavier vehicles through what is termed a limit curve (Automobile Fuel Economy standards, 2010). Penalties are applied using a sliding scale. The fuel economy limits continue to increase in response to regulation (Automobile Fuel Economy standards, 2010).

In a European context, the standards are realistic meeting lesser resistance from concerned civil society portions due to the predominance of small cars, efficient and widely-spread public transportation and the proliferation of the more efficient diesel vehicles.

Japan followed in the footsteps of the EU with its own stringent weight-based standards (IPCC, 2007)

The USA has been adopting fuel economy standards since the seventies which have been slightly waxing and waning over time for light trucks, and constant for passenger cars since 1990 (GFEI, 2014). Light Duty Vehicles were regulated using different standards for passenger cars and light trucks. The US standards count on fuel economy, unlike which target fuel consumption. The same average fuel efficiency was required from each manufacturer regardless of vehicle attributes. It was calculated by the following formula

(Source: Centre for Climate and Energy solutions, 2014)

The downside of this approach is that the playfield is not level for large vehicle segments since compliance is easier for smaller ones. The standards were assessed by experts to have led to fuel savings of billions of barrels of oil over the years (Government Accountability Office, 2008).

With the support of the Obama administration, the US Environmental Protection Agency jointly with the National highway Traffic Safety administration has set fuel economy standards for 2017-2025 vehicles. Vehicles are classified on size basis for two broad categories: passenger cars and light trucks. Vehicle size (footprint) which is determined in a standardized way enters a formula that accounts as well for a manufacturer’s production or sales level. The standards are designed to accomplish a US fleet average fuel economy, by 2016, of at least 35.5 (GFEI, 2014). The target for 2025 is 54.5 mpg (New York Times, 2012). A shortcoming of that standards is restricting classifications of vehicles to size, which in light of the earlier discussion on the factors affecting energy efficiency of vehicles, is a factor among many.

4. Driving Cycles

For the driving cycles to be fully representative, they need extensive detailed data about characteristics of driving in locations where they are applied. Also, the vehicles used for designing the cycle must match the running models. Other factors, such as roads elevation, air and wind need to be accounted for. Some claim that manufacturers design vehicles to match the driving cycle at the destination market’s cycle, if there is one.

3. Morocco in a North African context

Morocco entertains levels of GDP per capita, at purchasing power parity, lower than Egypt’s, and considerably lower than Tunisia’s. It figured to 5,200, 5,300 and 5,500 for 2011, 2012 and 2013, respectively (CIA, 2014). Egypt, on the other hand, had a GDP per capita remaining constant at $6,600 over the period from 2011 to 2013 (CIA, 2014).

Morocco had a GINI index rounding up to 40 over the entire last decade (IMF, 2013). It was narrowly close to Tunisia’s and higher than Egypt’s, indicating a relatively more equitable distribution of income in Egypt.

Motorization rates in Morocco were 81 and 84 per one thousand inhabitants for the years 2011 and 2012, respectively- higher than the 50-odd rates of Egypt, but considerably lower than those of Tunisia standing in the range of one hundred and twenties. The higher motorization rates in Morocco despite Egypt’s better GINI coefficient, higher GDP per capita and cheaper highly subsidized motor fuel can be attributed to two factors. First, there is the higher rate of urbanization in Morocco where urban population makes up 57.77% of total population, whereas Egypt’s rate is 43.7 (Quandl, 2014). Cities of Casablanca, Rabat, Fes, Meknes and Agadir are highly urbanized and the levels of commuting are quite high (Focal Points, 2014). In Egypt, relatively high levels of urbanization and commuting are confined to Cairo. Tunisia, on the other hand, has a high level of urban population of 66.75% (Quandl, 2014).

Figure 1: Total Vehicles on the road. (OICA 2014)

Figure 2: Sales of new LDVs in Tunisia and Egypt. (Matthias Gasnier 2014)

Figure 3: Sales of new LDVs in Morocco. (Matthias Gasnier 2014)

The total number of vehicles on the road, shown in Figure1, reflects the difference in population sizes and growth rates. Tunisia’s population has remained around 10 million since 2006; Morocco’s population has increased by about 2 million to around 32 million from 2006; Tunisia’s population has remained around 10 million since 2006 while Egypt increased by 12 million to around 82 million over the same period (Quandl, 2014). Moroccan population growth rate in 2014 has been 1.02%

GDP growth in Morocco has averaged 4.43 from 1999 to 2014 with only two incidences of sharp fluctuations (tradingeconomics.com, 2014). The steady GDP growth and the low population growth rates compared to Arab countries are concomitant with a constant steady increase of total vehicles on the road of 2.36 million, 2.45 million, 2.6million and 2.72 million for 2009, 2010, 2011 and 2012, respectively (OICA, 2012).

Sales of new LDVs, on the other hand, were 64,517, 79,627, 82,294 vehicles for 2009, 2012 and 2013, respectively. The increase in sales can be attributed to elements of the Moroccan policy environment, which are discussed in the next section.

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