Search results
Results from the WOW.Com Content Network
The efficiency of internal combustion engines depends on several factors, the most important of which is the expansion ratio. For any heat engine the work which can be extracted from it is proportional to the difference between the starting pressure and the ending pressure during the expansion phase.
English: US DOE car efficiency by loss. FIGURE 3-1 Example energy flows for a late-model midsize passenger car: (a) urban driving; (b) highway driving. [SOURCE: U.S. Department of Energy
Because of their light weight and small motors, they are extremely energy-efficient with a typical energy efficiency of 1.1 kWh (4.0 MJ) per 100 km [56] (1904 MPGe 810 km/L 0.124 L/100 km), even more efficient than bicycles and walking. However, as they must be recharged frequently, they are often collected overnight with motor vehicles ...
The Nissan Sentra proves that affordable and efficient cars don't have to look dorky. It's powered by a 149-hp 2.0-liter inline-four and continuously variable automatic transmission (CVT).
The transfer of energy amounts to an efficiency improvement and the resulting power density of the engine is also improved. The intake air is typically cooled so as to reduce its volume as the work produced per stroke is a direct function of the amount of mass taken into the cylinder; denser air will produce more work per cycle.
Example energy flows for a late-model (pre-2009) midsize passenger car: (a) urban driving; (b) highway driving. Source: U.S. Department of Energy [4] [5] Most of the fuel energy loss in cars occurs in the thermodynamic losses of the engine. Specifically, for driving at an average of 60 kilometres per hour (37 mph), approximately 33% of the ...
Input energy is the energy stored in the fuel. According to the U.S. Department of Energy, fuel cells are generally between 40 and 60% energy efficient. [62] This is higher than some other systems for energy generation. For example, the internal combustion engine of a car can be about 43% energy efficient.
Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier into kinetic energy or work.