Coefficient of efficiency - is everything right?


No action is performed withoutlosses - they are always there. The result is always less than the effort required to achieve it. About how large the losses are in the performance of work, and indicates the efficiency (EFFICIENCY).

What is hidden behind this abbreviation?In fact, this is the efficiency factor of the mechanism or the indicator of rational energy use. The magnitude of the efficiency does not have any units of measurement, it is expressed as a percentage. This coefficient is defined as the ratio of the useful work of the device to the expenditure on its functioning. To calculate the efficiency, the calculation formula will look like this:

Efficiency = 100 * (useful work performed / work expended)

In various devices to calculate thisrelationship, different values ​​are used. For electric motors, the efficiency will look like the ratio of the useful work done to the electrical energy received from the grid. For thermal machines, the efficiency will be determined as the ratio of the useful work done to the amount of heat expended.

To determine the efficiency, it is necessary that alltypes of energy and work were expressed in one unit. Then it will be possible to compare any objects, for example nuclear power plants, power generators and biological objects, in terms of efficiency.

As already noted, due to the inevitable losses atthe efficiency coefficient is always less than 1. Thus, the efficiency of thermal plants reaches 90%, the efficiency of internal combustion engines is less than 30%, the efficiency of an electrical transformer is 98%. The concept of EFFICIENCY can be applied both to the mechanism as a whole, and to its separate nodes. At the general estimation of efficiency of the mechanism as a whole (its EFFICIENCY) the product of efficiency of separate components of this device is taken.

The problem of efficient use of fuelappeared not today. With the continuous increase in the cost of energy resources, the issue of increasing the efficiency of mechanisms is transformed from a purely theoretical one into a practical question. If the efficiency of an ordinary car does not exceed 30%, then we simply throw out 70% of our money spent for fueling cars.

Considering the efficiency of the engine (engineinternal combustion) shows that losses occur at all stages of its operation. So, only 75% of incoming fuel burns in the cylinders of the engine, and 25% is released into the atmosphere. Of all the burnt fuel, only 30-35% of the heat released is spent to perform useful work, the rest is lost or lost with the exhaust gases, or remains in the cooling system of the car. Of the received power, about 80% is used for useful work, the remaining power is spent on overcoming frictional forces and is used by the auxiliary mechanisms of the car.

Even with such a simple example, analysiseffectiveness of the mechanism allows you to determine the direction in which work is to be carried out to reduce losses. So, one of the priority areas is ensuring complete combustion of fuel. This is achieved by additional spraying of fuel and increased pressure, so engines with direct injection and turbocharging become so popular. The heat removed from the engine is used to heat the fuel in order to better evaporate it, and the mechanical losses are reduced by using modern types of synthetic oil.

Here we have considered such a concept asefficiency, describes what it is and what it affects. The efficiency of its operation is considered on the example of ICE and directions and ways of increasing the capabilities of this device are determined, and, consequently, efficiency.

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