What is a valid indicator of an engine? What are the main ones?

The performance index of the engine is used to characterize the performance characteristics of the engine and as the basis for evaluating the performance of various engines. Generally, there are power indicators, economic indicators, strengthening indicators, compact indicators, environmental indicators, reliability indicators, durability indicators, manufacturability indicators, internal combustion engine speed characteristics, etc.

The dynamic index is an index that characterizes the functional force of the engine, and the effective torque, effective power, speed and average effective pressure of the engine are generally used as indicators to evaluate the power of the engine.

The torque output from the engine is called the effective torque, which is the torque of the engine. Generally, the larger the bore of the engine, the longer the piston stroke, the greater the torque of the engine, and the stronger the acceleration ability and climbing ability.

Engine economy indicators include effective thermal efficiency and effective fuel consumption rate. The strengthening index refers to the evaluation index of the engine's ability to withstand thermal load and mechanical load, generally including liter power and strengthening coefficient. The compactness index is used to characterize the overall compactness of the engine, which is usually measured in terms of specific volume and specific mass.

Environmental indicators are used to evaluate engine exhaust quality and noise levels, which are related to human health and the environment on which they live. Each country** has established strict control regulations to reduce the environmental pollution caused by engine exhaust and noise. China implemented the China VI standard in 2020.

The reliability index is an index that characterizes the ability of the engine to work normally and continuously under the specified use conditions. The indicators to evaluate reliability include mileage of the first failure, mileage between failures, and damage rate of major parts.

The durability index refers to the extreme time that the main parts of the engine are worn to the point where they can no longer continue to work properly. It is usually measured in terms of the engine's overhaul mileage, which is the number of miles the car travels between the time the engine leaves the factory and the first overhaul. The vast majority of engines now have an overhaul mileage of more than 200,000 kilometers.

Manufacturability index refers to the index to evaluate the quality of engine manufacturing manufacturability and maintenance process. If the engine structure is well processed, it is easy to manufacture and maintain, which can reduce production costs and maintenance costs.

The engine indication index is used to evaluate the perfection of its internal circulation, reflecting the work of the working fluid in the cylinder on the piston. It is the basis of effective indicators, but it cannot comprehensively reflect the performance of the whole engine; The performance of the engine is based on the work output of the crankshaft, but it cannot accurately indicate the perfection of the internal processes of the engine.

Effective power, effective torque and other dynamic indicators.

There are mainly power indicators, emission indicators and economic indicators. Hope it works for you.

Indication index of the engine: indication work (or cycle indication work): the work done by the working fluid on the piston after the cylinder completes a cycle, expressed by WCI (J).

wci=∮pdv。Average indication pressure pi: the indicated work done per cycle of the working volume of the engine per unit cylinder; Unit:

kpa。Indication power ni: the indicated work done per unit of time, unit:

Indicated fuel consumption rate GI: The amount of fuel consumed per unit of indicated work, expressed by GI, GI (1000 gf Ni) [G kw·h].

Indication thermal efficiency I: the ratio of the actual cycle indication work WCI to the calorific value Q1 of the fuel used, expressed by i, gi — [g kw·h. Valid Indicators:

Mechanical loss power nm: The amount of power consumed due to mechanical loss. Effective power ne:

The power output of the crankshaft to the outside world, unit: [kw]; Effective torque me: is the average torque output of the crankshaft when the engine is working.

Unit:Mean effective pressure pe:

The circulating effective work per unit cylinder working volume. Unit: KPA.

Power per litre nl: The effective power emitted by the engine per litre of working volume. Unit:

kw/l]。Specific weight: the ratio of the net weight g of the engine to the power emitted ne.

ge＝g/ne 。Effective Fuel Consumption Rate: The amount of fuel consumed per unit of effective work.

ge＝1000×gf/ne [g/kw·h]。Effective thermal efficiency: The ratio of the effective power of the engine to the heat Q1 emitted by the fuel consumed.

Power index: characterizes the size of the engine's workmanship ability, economic index: engineThermal efficiencyand fuel consumption rate, environmental performance indicators:

Refers to the quality of engine emissions and noise levels.

Reliability index: the ability to work normally and continuously under specified conditions, and the manufacturability index: the convenience of manufacturing and maintenance.

Compactness index: the degree of compactness of the engine structure, strengthening index: evaluation of the heat load of the engine.

and the capacity of mechanical loads.

The index based on the output work of the crankshaft is called the effective performance index. Mainly: 1) engine dynamics indicators, including effective work and effective power.

Effective torque. Average effective pressure. rpm n and piston average speed; 2) Engine economy indicators, including effective thermal efficiency.

effective fuel consumption rate; 3) Engine enhancement indicators, including liter power plthan the quality of me. Reinforcement coefficient pmecm

Indicator index: the dynamic and economic indicators obtained according to the dynamometer diagram. It is a performance index based on the work done by the working fluid on the piston in the cylinder.

Significance: It is used to evaluate the quality of the working cycle and study the working process of the engine. Valid Indicators:

Taking into account the indicators of mechanical losses. Less than the indicator is indicated. It is a performance index based on the work output from the crankshaft.

Significance: It is used to evaluate the performance of the engine.

Indicators and their significance:The dynamic and economic indicators obtained according to the dynamometer diagram. It is a performance index based on the work done by the working fluid on the piston in the cylinder.

It is used to evaluate the quality of the working cycle and study the working process of the engine.

Effective indicators and their significance:Taking into account the indicators of mechanical losses. Less than the indicator is indicated. It is a performance index based on the work output from the crankshaft. It is used to evaluate the performance of the engine.

An engine is a machine that can convert other forms of energy into mechanical energy, including internal combustion engines (gasoline engines, etc.), external combustion engines (Stirling engines, steam engines, etc.), electric motors, etc., such as internal combustion engines, which usually convert chemical energy into mechanical energy.

1. Engine application:

The engine is applied to both the power generation unit and the entire machine including the power unit (e.g., gasoline engine, aero engine).

2. The birth of the engine

The engine was first born in England, so the concept of the engine also originated from the English language, and its original meaning refers to the "mechanical device that produces power".

3. Classification of engines:

Automobile engines can be divided into two categories: gasoline engine and diesel engine, their basic structure is the same, are composed of two major institutions and five systems, namely crank connecting rod mechanism, valve mechanism, fuel supply system, lubrication system, cooling system, ignition system and starting system.

4. The working principle of the engine:

The engine does not turn on its own for no reason, there must be an external force to give it the original power, and this external force is provided by the engine's starting system. When the engine is in normal operation, its duty cycle consists of four piston strokes: intake, compression, work and exhaust.

1. Effective torque, the torque output of the engine is called effective torque, that is, the torque of the engine. Generally, the greater the torque of the engine, the stronger its acceleration ability and climbing ability. Generally, the larger the bore of the engine, the longer the piston stroke, and the greater the torque of the engine.

This is also one of the reasons why large displacement engines have more torque.

2. Effective power, the effective work output of the engine per unit time is called effective power, that is, the power of the engine, which is equal to the product of the effective torque and the angular velocity of the crankshaft. Engine power is the most important indicator of engine performance, and the top speed of a car is determined by engine power.

3. Engine speed, the number of revolutions per minute of the engine crankshaft is called engine speed. The speed of the engine is related to the number of work times per unit time or the effective power of the engine, that is, the effective power of the engine changes with the different speeds. Therefore, when indicating the effective power of the engine, its corresponding speed must also be indicated.

4. The average effective pressure, the effective work emitted by the working volume of the unit cylinder is called the average effective pressure, the greater the average effective pressure, the stronger the working force of the engine. Many engines are turbocharged today, and the average effective pressure is higher than that of naturally aspirated engines.

The effective performance index of the engine is obtained by the engine laboratory test.

In the engine laboratory, the actual performance of the engine in terms of fuel economy, power output, and reliability can be obtained through a series of tests and data collection. These indicators can be used as effective performance indicators of the engine to facilitate the user's comparison and selection. The effective performance indicators of the engine include:

Maximum power, maximum torque, fuel consumption, emissions, etc. Through the comparison of these parameters, it can help people choose the engine that suits their own needs and improve the efficiency of the engine.

There are other engine performance metrics that are also very important, such as the compression ratio of the engine, the efficiency of the cooling unit, the efficiency of the air intake system, and so on. These metrics can have a big impact on engine performance in different usage scenarios and different vehicle configurations. The effective performance indicators of the engine are obtained by the engine manufacturer through experiments under laboratory control conditions, and these indicators are important criteria for judging the quality of the engine, and other factors need to be considered comprehensively to choose the engine that suits their needs.

The importance of the engine

1. Provide driving power: the engine is the core of the car to provide driving power, the stronger it is, the more smoothly the vehicle will be able to drive, the quieter and more comfortable, enough to meet people's various needs for driving.

2. Complex structure and high technical difficulty: As the core index of the vehicle, the engine involves complex devices such as cylinders, crankshafts, gas distribution, and engine control, which require the application of advanced materials, manufacturing technology and reliable control systems, and has considerable technical content and difficulty.

3. Affect fuel economy performance: The design and manufacturing level of the engine directly affects the fuel economy, and a good engine can maximize fuel utilization, reduce fuel consumption, and prolong the running time and service life of the vehicle.

4. Environmental performance: With the popularization of the concept of environmental protection, the environmental performance of the engine has attracted more and more attention. In the process of working, the engine produces exhaust gas and noise, which poses a threat to the environment and human health, and an excellent engine should have the characteristics of low carbon emissions, low noise and high efficiency.