The role and working principle of three-way catalytic converter

In recent years, environmental protection standards have become increasingly strict across the country, and three-way catalytic converters have become a standard component in modern vehicles. While many experienced drivers are familiar with this device, not everyone understands its function or how it works. **The Function of a Three-Way Catalytic Converter – Exhaust Gas Purification** The three-way catalytic converter is one of the most important devices used to clean exhaust emissions from vehicles. It converts harmful gases such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) into harmless substances like carbon dioxide (CO₂), water (H₂O), and nitrogen through oxidation and reduction reactions. This process helps reduce the environmental impact of vehicle emissions. As environmental regulations continue to tighten, more and more cars are equipped with catalytic converters and oxygen sensors. These devices are installed in the exhaust system and are also known as ternary catalytic converters due to their ability to handle all three main pollutants simultaneously.  The primary purpose of a three-way catalytic converter is to purify the exhaust gas before it is released into the atmosphere. When high-temperature exhaust gases pass through the converter, the catalyst inside enhances the activity of CO, HC, and NOx, triggering chemical reactions that transform them into less harmful substances. For example, CO is converted into CO₂, which is non-toxic. Hydrocarbons are oxidized into water and CO₂, while NOx is reduced into nitrogen and oxygen. This process ensures cleaner emissions and plays a key role in reducing air pollution.  **How the Three-Way Catalytic Converter Works** When hot exhaust gases enter the catalytic converter, they come into contact with the catalyst material. The converter contains a porous ceramic carrier coated with precious metals like platinum, rhodium, and palladium. These materials act as catalysts, accelerating the chemical reactions needed to break down harmful gases. At high temperatures, CO is oxidized into CO₂, HC compounds are turned into water and CO₂, and NOx is broken down into nitrogen and oxygen. This transformation reduces the toxicity of the exhaust and makes it much safer for the environment. The converter is typically made of two layers of stainless steel with an insulating layer in between. The middle section holds the catalytic material, which is essential for the conversion process. **Tips for Proper Use of the Three-Way Catalytic Converter** 1. Avoid sudden fluctuations in engine speed. 2. Do not use leaded gasoline, as it can damage the catalyst. 3. Avoid prolonged high-speed driving. 4. Ensure the ignition timing is set correctly. 5. Limit long periods of idling. 6. Do not remove the high-voltage wire for testing. 7. If there is a misfire or cylinder malfunction, stop and check immediately. 8. Under normal conditions, the catalytic converter should not be removed unless necessary. **Performance Characteristics** The three-way catalytic converter is known for its stability, reliability, and long lifespan. It is widely used in various car models, including Toyota, Honda, Buick, Audi, Volkswagen, Hyundai, Suzuki, and Changhe. The converter uses a ceramic carrier coated with precious metals. The carrier itself does not participate in the reaction but provides a surface for the catalyst to work on. The catalyst then transforms harmful gases into safe byproducts. This technology has proven to be highly effective in reducing emissions. At optimal temperatures (around 400°C to 800°C), the converter performs at its best. However, if the temperature is too low, the efficiency drops significantly. Similarly, excessive heat can cause the catalyst to degrade over time. Maintaining the correct air-fuel ratio (14.7:1) is crucial for the converter to function efficiently. Overall, the three-way catalytic converter is a vital component in modern vehicles, helping to protect both the environment and public health.

Piezoelectric Material

Yuhai piezo materials include : hard piezo material, soft piezo material and lead free piezo material

Soft piezo material exhibits: larger piezoelectric constants, higher permittivity, larger dielectric constants, higher dielectric losses, larger electromechanical coupling factors, low mechanical quality factors, a lower coercive field, poor linearity, and is easier to depolarize. The ideal application of soft piezo materials is sensing needs. Yuhai soft pizeo materials are PZT-5, PZT-5H, PSnN-5 and PLiS-51.

Hard piezo material exhibits: smaller piezoelectric constants, lower permittivity, smaller dielectric constants, lower dielectric losses, smaller electromechanical coupling factors, high mechanical quality factors, a higher coercive field, better linearity, and is harder to depolarize. The ideal application of hard piezo materials is high power transducer needs. Yuhai hard pizeo materials are PZT-4, PZT-8, PCrN-4 and PBaS-4.

Yuhai company developped lead free piezo material BaTiO3 and apply for the Chinese Patent in 2011, to meet the needs of environmental protection in today's society.

Piezoelectric ceramic material

Properties and Classification

General description of material properties	Material Code	Properties	Application
Soft PZT ceramic	PZT-51	Characteristics: larger piezoelectric constants, higher permittivity, larger dielectric constants, higher dielectric losses, larger electromechanical coupling factors, low mechanical quality factors, a lower coercive field, poor linearity, and is easier to depolarize.	low-power ultrasonic transducers
	PZT-52		low-frequency sound transducers
	PZT-53		applications with high g coefficient, for example,
	PZT-5H		microphones,vibration pickups with preamplifier
	PLiS-51		low-frequency vibration measurements
	PMgN-51		Hydrophones, transducers in medical diagnostics
	PSnN-5		Actuators
Hard PZT ceramic	PZT-41	Characteristics: smaller piezoelectric constants, lower permittivity, smaller dielectric constants, lower dielectric losses, smaller electromechanical coupling factors, high mechanical quality factors, a higher coercive field, better linearity, and is harder to depolarize.
	PZT-42		High-power acoustic applications
	PZT-43		Hydroacoustics, sonar technology
	PZT-82		piezomotor
	PCrN-4
	PBaS-4
Lead free piezo ceramic	BaTiO3	Characteristics: Low density, low curie temperature, lead free.	Ultrasonic transducers suitable for low-temperature underwater, for example ultrasonic transducer in fishfinder

Piezoelectric Material,Piezo Ceramic Element,Piezo Electric Cylinder ,Piezo Sphere

Zibo Yuhai Electronic Ceramic Co., Ltd. , https://www.yhpiezo.com