Kwong Kee




Auto Environmental Protection:


What is automobile environmental protection?

Few People are clear on this concept. Please see below the contents and new trends of automobile environmental protection. The contents of automobile environmental protection are as follows:

  • Automobile Noise: Automobile Noise means mainly the noise including engine work noise and noise generated by vibration and transmission by automobile during running. The current methods of evaluation and testing are mainly outside noise and inside noise. The light automobiles are required to be less than 85db (A) to avoid noise pollution.
  • Automobile Exhaust Gas Pollution: Automobile Exhaust Gas Pollution means mainly the exhaust gas discharged from the exhaust tube of the automobile engine. The component of the contaminant depends on the type of the automobile engine. Automobile Exhaust Gas Pollution is the main pollutant source of the automobile as well as one essential item in automobile environmental protection.
  • Fuel Evaporation Pollution: Fuel Evaporation Pollution aims mainly at gasoline evaporation of gasoline vehicles. Since gasoline is a substance with extreme strong volatility and there are a large amount of components harmful to human body in its volatiles, the item of fuel volatiles control is added to the control of automobile environmental protection.
  • Crankcase Pollution: Crankcase Pollution means the inflammable gas that is leaked form piston ring opening of the engine and not completely burnt in the crankcase of the engine. Since it contains components harmful to human body such as carbonic oxide (CO), exhaust gas in the engine crankcase is not allowed to be discharged to atmospheric environment.

With continuous development in economy, automobile becomes increasingly important, but the traditional automobile on petroleum fuel destroys the environment. This issue brings about wide concern of many people.


How to cut down the emission of toxic gas from automobile?

This is a complicated technical and social issue. The methods to solve this problem are as follows: first, government law and regulation and policy; second, maintenance and supervision in the link of engine use; third, advanced control technology actively adopted by manufacturers to improve the emission of toxic gas.

The new trends emerged in automobile environmental protection at present that deserve our consideration. 

  1. Law and regulation on automobile emission become increasingly strict.
  2. The demand for environment from the society becomes higher and higher so that the associated effort from all works of life are required.
  3. Hydrogen-powered automobile is about to be popular.
  4. Emission control products are widely applied.
  5. Check and control on automobile pollution are enhanced.

These new trends raise higher requirement to our manufacturers and the society. We will make unremitting effort for this and return a fresh world to people.




What is Muffler?

A muffler is a unit that is mounted on the air duct or in the air intake/outtake system of aerodynamic equipment (e.g. air blower and air compressor) to reduce noise. Muffler is an effective tool to control noise since it can block the spread of sound wave and allow the airflow to pass through.


Types of Muffler.

Dissipative muffler, reactive muffler, dissipative and reactive compound muffler, micro-perforated panel muffler, micropore muffler and active muffler.


Why doe the Engine Muffler emit black smoke?

The reason for the above failure is higher blend gravity of inlet gas combustion. In case of this situation, clean or replace the air filter at first. If the problem is not solved, please adjust or clean the engine carburetor.


Why does the muffler emit blue smoke in the running of engine?

The reason for the above failure is that engine oil joins in combustion. After detecting this failure, check oil rule to see if engine oil is in excess at first. If so, run 10 minutes after draining the redundant engine oil. Inspection and repair of the engine are required if the problem is not solved.


How to evaluate the performance of muffler?

The performance of the muffler can be evaluated on the below three aspects:

  1. Noise Elimination Performance is the noise reduction and spectrum characteristic of the muffler. Noise reduction of the muffler is generally expressed with sound transmission loss and insertion loss as well as end sound level difference at air outtake (or air intake) in field test. The spectrum characteristic of the muffler is generally expressed with noise reduction of octave band of 1/3 octave band.
  2. Aerodynamic Performance is resistance loss or resistance coefficient. The resistance loss of the muffler is generally expressed with the full pressure difference between inlet and outlet of the muffler; the resistance coefficient can be worked out with dynamical pressure and resistance loss of the muffler. The aerodynamic performance of the equipment must be affected should the muffler is mounted on the air duct. If only the noise elimination performance of the muffler is concerned with the aerodynamic performance neglected, the efficiency of the equipment might be greatly reduced by the muffler or even the equipment does not work under some circumstances.
  3. Structure Performance: For the mufflers with the same noise elimination performance and aerodynamic performance, the smaller in geometrical size, the cheaper in price, the longer in service life, the better.


Dose the airflow have impact on the muffler?

When the airflow passes through the muffler, a new noise is superposed to the original pipe noise and thereby the real use effect of the muffler is affected. This noise is airflow-regenerated noise that is radiated as a result of local resistance force applied to airflow, turbulent flow generated by frictional resistance or vibration of muffler components activated by airflow, The value of the airflow-regenerated noise depends mainly on airflow speed and the structure of the muffler. In general, the higher the airflow speed or the more complicated (such as duct section mutation, bend or obstruction, etc.) the internal structure of the muffler, the bigger the noise generated.


Catalytic Converter


What is Three-Way Catalytic Converter?

Three-Way Catalytic Converter is a unit mounted in the exhaust system of the engine that converts simultaneously three major contaminants carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) into harmless water (H2O), carbon dioxide (CO2) and nitrogen gas (N2). As an active pollution control technology, it is widely applied in the automotive industry. 


The Operational Principle of Three-Way Catalytic Converter.

When high temperature exhaust gas passes through the three-way catalytic converter unit, the wash-coat in catalytic converter enhances the catalytic activity of the three gases CO, HC and NOx and oxidation-reduction chemical reaction occurs, in which most of the CO is oxidized to be colorless nontoxic carbon dioxide under high temperature; HC compound is oxidized to be water (H2O) and carbon dioxide; NOx is reduced into nitrogen gas and oxygen gas. The exhaust becomes less harmful and environmental friendly.


Failure Model of Three-Way Catalytic Converter?

  1. Three-Way Catalytic Converter generally fails in mechanical damage, high temperature aging, lead poisoning, chemical masking, etc. among which, high temperature aging and lead poisoning result in fatal damage to catalyst. Whatever form of failure will finally reduce the catalytic reaction of device. As a result, the chemical reactions don not work, exhaust contaminant increases rapidly and the atmospheric environment is polluted.
  2. The reason for overheating of Three-Way Catalytic Converter is caused by excessive heat from the exhaust gases, What the catalyst components including precious metals such as platinum, palladium and rhodium on substrate are at high temperature for over period of time, precious metals are sintered. The temperature usually exceeds 900°C.


How to Determine the Failure of Three-Way Catalytic Converter?

You can stop by any emission test center near you to have an emission specialist to emission test your vehicle. If it meets the standard, your converter most likely works. Also, if a converter stops working, you will notice a nuisance smell from the exhaust.


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