Fuel consumption has been shown to be the fundamental metric to judge fuel efficiency improvements from both an engineering and a regulatory viewpoint. Norgaard University of California, Berkeley Confronting Consumption provides a fresh new look at the systemic problems of consumption in the global economy. As engine speed increases, the combustion interval in the crank-angle domain also increases and thus delays the end of combustion. Hybrid systems also enable the engine to be downsized and to operate at more efficient operating points.


What has changed is the greater need to reduce fuel consumption and the developments in controls, batteries, and electric drives. Martin Cart Buying Options. It is measured in the United States in gallons per miles, and in liters per kilometers in Europe and elsewhere throughout the world. Implementing certain engine technologies may require changes in fuel properties, and vice versa.

U.S. Energy Information Administration (EIA) - Consumption & Efficiency

Low speeds in stop-and-go urban traffic. This is commonly called cracking.

The distinction between these two types of engines is changing with the development of engines having some of the characteristics of both the Otto and the diesel cycles. Also, you can type in a page number and press Enter to go directly to that page in the book. Women and the Environment A dynamic, vital book that takes your breath away!

Manufacturers self-certify their vehicles using preproduction prototypes representative of classes of vehicles and engines. These wide-ranging analyses of consumerism successfully bring together the cultural and the ecological, the structural and the symbolic, the local and the global.

Air conditioning use under hot ambient conditions. The large capital investment in manufacturing capacity, the motor vehicle fleet, and the associated fuel infrastructure all constrain the rate of transition to new technologies. This ultimately limits the power density i.

In contrast, fuel economy measures how far a vehicle will travel with a gallon of fuel. Vicki Robin Journal of Positive Futures The authors are to be commended for breaking the code of silence surrounding consumption and engaging the debate. Therefore, this type of engine tends to have high power density e. The high values are due to the many decelerations that the schedule contains. Consumption deserves serious attention.

Global Environmental Politics. To search the entire text of this book, type in your search term here and press Enter. It plots the engine efficiency as functions of torque and speed. Environmental Protection Agency. Early engines burned coal and vegetable oils, but their use was very limited until the discovery and exploitation of inexpensive petroleum.

Fuel consumption is also the appropriate metric for determining the yearly fuel savings if one goes from a vehicle with a given fuel consumption to one with a lower fuel consumption. Modern aeronautic engines. Air conditioning is turned off during the certification test. Engines became more powerful, and vehicles became heavier, bigger, and faster. The power delivered to the output shaft of the engine is termed the brake output power, and should not be confused with the braking energy mentioned in the previous section.

Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website. As a metric, fuel economy actually measures distance traveled per unit of fuel. Normally high octane enables increases in the compression ratio and hence efficiency. Throughout this report, fuel consumption is used as the metric owing to its fundamental characteristic and its suitability for judging fuel savings by consumers. Women and the Environment.

Confronting Consumption

Brake thermal efficiency is the ratio of brake power output to the energy rate into the system the mass flow rate of fuel times its energy density. The analysis focuses on test schedules and neglects the effects of wind and hill climbing. Thus converting the tractive energy into fuel consumption is best done using a detailed step-by-step simulation. This equation provides the means for relating pumping losses, engine friction, and auxiliary load to the overall engine efficiency. Search Advanced Search close Close.

The MIT PressCurrent Issues & TrendsConfronting Consumption

In cases where the committee has used fuel economy data from the. It is actually fuel consumption. Also shown in the figure is the decreasing influence on fuel savings that accompanies increasing the fuel economy of high-mpg vehicles. The unsteady driving characteristic of many drivers increases fuel consumption.

The issue of excessive, careless, heat exchanger.pdf and ignorant consumption has been conspicuously absent in all the talk about sustainability. The monitoring of engine and emission control parameters by the onboard diagnostic system identifies emission control system malfunctions. Fuel consumption is the inverse of fuel economy. These assumptions are very important.

Confronting Consumption

Ethanol has a higher octane rating than that of gasoline, and this is often cited as an advantage. Endorsements The issue of excessive, careless, and ignorant consumption has been conspicuously absent in all the talk about sustainability.

Also, the reduction of vehicle acceleration capability allows the use of a smaller, lower-power engine that operates closer to its best efficiency. The unit of total energy is used to allow for an easier comparison between the schedules on the basis of energy distribution.