Catalytic converters are known for their crucial role in reducing harmful exhaust emissions in petrol engines and are often the center of discussion. But do diesel engines have catalytic converters?
Yes, today’s diesel engine comes with catalytic converters. Even catalytic converters become a must-need for the vehicle. You can’t drive a car in the USA that doesn’t have these precious components.
Otherwise, doing so can cost you up to 1,000 dollars in fines. The catalytic converter comes in various types and works differently than those found on gasoline engines. Let’s get details!
Article Summary
- Do Diesel Engines Have Catalytic Converters?
- Where Are Catalytic Converters on Diesel Located?
- Types of Catalytic Converter That Diesel Engines Use
- Purpose of A Catalytic Converter on Diesel Engine
- Why Does A Car Have Multiple Catalytic Converters?
- How Does Catalytic Converters Work in A Diesel Car?
- Can Diesel Engines Run Without a Catalytic Converter?
- FAQs on Do Diesel Engines Have Catalytic Converters
Do Diesel Engines Have Catalytic Converters?
Yes, diesel engines have catalytic converters. The presence of a catalytic converter on a diesel engine depends on the engine’s model and manufacturing years.
Till 1970, there was no law on emission control system. So, the car manufacturer didn’t focus on the toxic emission issues.
In 1970, the Environmental Protection Agency (EPA) established the Clean Air Act to control air emissions from stationary and mobile sources.
In 1990, the authority made it mandatory for every car to pass emission tests to get a permit for driving on the road.
Since then, the manufacturer has started adding and fixing catalytic converters to diesel engines that help convert pollutants into harmless gasses.
So, the diesel engine made after 1990 should have a catalytic converter. Currently, all modern cars and all types of engines come with catalytic converters to pass the emission test.
Where Are Catalytic Converters on Diesel Located?
The location of catalytic converters on diesel engines depends on the model, manufacturing years, and brands.
A diesel engine’s first catalytic reduction system is the diesel oxidation catalyst (DOC), located downstream from the exhaust manifold.
In today’s cars, catalytic converters near the engine’s exhaust manifold. The catalytic converter exposes it to extremely hot exhaust gases and heats up quickly. Placing it near the engine allows it to reduce undesired emissions during its warm-up period.
The closer the catalytic converter is to the engine, the faster it can heat up and activate the catalyzation compounds.
You can also find a catalytic converter on the exhaust or between the mufflers. Catalytic converters are made of valuable metals, making them a special target for thieves.
Types of Catalytic Converter That Diesel Engines Use
The diesel engine usually has a two-way catalytic converter because vehicles have only oxidation reactions in the converter.
It oxidizes HC, NO, and CO to H2O, NO2, and CO2. The oxygen removal reaction reduces the NOx-related contaminants.
The low-pressure and high-pressure exhaust gas recirculation also helps clean the NOx-related pollutant. So, diesel engines don’t require a three-way catalytic converter.
In comparison, two-way catalytic converters depend on physical reactions to turn pollutants into risk-free gases, while three-way converters depend on chemical reactions.
Diesel engines also have more sulfur than gasoline engines. Sulfur participates in a chemical reaction inside the three-way catalytic converter. So, it can’t clean the exhaust fumes more effectively than the two-way type.
However, some of today’s diesel engines use ultra-low sulfur diesel (ULSD) fuel containing little sulfur. This type of engine can use the three-way catalytic converter. Compared to the USA, ULSD is normal in Europe.
So, most of the diesel engines in Europe have three-way catalytic converters. However, regular diesel fuel is normal in the USA; hence, a two-way catalytic converter is dominant here.
Purpose of A Catalytic Converter on Diesel Engine
A catalytic converter provides several benefits to the diesel engine. Firstly, it helps eliminate emissions of harmful pollutants to enhance air quality and public health.
The catalytic converter also improves the engine’s overall performance and fuel efficiency while helping pass the emissions test.
It can reduce engine noise and make driving comfortable. Another benefit is that the catalytic converter helps boost the engine’s longevity by protecting the engine parts from wearing out.
However, catalytic converters may become jammed over time and need maintenance to retain their functionality.
To avoid this problem, many diesel engines use a combination of DPFs and DOCs to reduce hydrocarbon emissions and capture particulate matter.
Why Does A Car Have Multiple Catalytic Converters?
A catalyst causes a chemical reaction inside the catalytic converter without being changed chemically.
This honeycomb-like object consists of various elements like platinum, rhodium, and cerium that turn into harmful emissions during the chemical reaction. Catalytic converters have two chambers: oxidation and reduction.
When the HC (hydrocarbons or fuel), CO (Carbon Monoxide), NOx (Oxides of Nitrogen), and O2 (oxygen) enter the converter, the reduction chamber converts them with its best effort.
Then, the oxidation chamber converts the CO, O2, and HC into CO2 and H20 and releases harmful emissions through the tailpipe.
Automakers are trying to increase compression while strictly maintaining the emission law. That’s why they add more catalytic converters in a vehicle to reduce emissions while increasing compression.
It’s a relatively new concept; you won’t find many vehicles with multiple catalytic converters. Toyota Camry has three inline catalytic converters, while Ford too.
How Does Catalytic Converters Work in A Diesel Car?
DOC is the most commonly used catalytic converter. The metal casing’s interior of the catalytic converter has two ceramic blocks and thousands of micro-cellular units.
The ceramic blocks are coated with palladium and platinum, which convert carbon monoxide and hydrocarbons into carbon dioxide and water.
It also heats the blocks and catalyzes the chemicals to convert them into nontoxic gasses. Compared to gasoline catalytic converters, diesel catalysts don’t use rhodium. It also has a diesel particulate filter to remove particular matter that may come from the engine.
However, catalysts can’t handle NOx. So, diesel engines use exhaust gas recirculation (EGR) to control NOx emissions.
Many manufacturers also use nitrogen injections that contain urea to create ammonia and convert the NOx into nitrogen and water.
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Can Diesel Engines Run Without a Catalytic Converter?
The catalytic converter isn’t compulsory for a diesel engine as it doesn’t participate in the vehicle’s locomotion process.
So, a diesel engine can run efficiently without a catalytic converter. Bad catalytic converters affect a car’s engine performance, and the car can make an irritating sound without using it.
If your vehicle doesn’t have a catalytic converter, it can also fail the emissions test. The reason is that driving a car without a catalytic converter or a bad catalytic converter in the USA is illegal.
A vehicle without a catalytic converter produces excessive emissions through the exhaust pipes that can harm the environment.
Hence, according to the 1970 Clean Air Act, the Environmental Protection Agency makes it compulsory for every vehicle to have a catalytic converter.
So, if you run a diesel engine car without a catalytic converter, you may charge a fine and fail the emissions test.
You might not want to pay a fine and hear annoying noises when you remove the catalytic converter. This component will not only help you pass the emission test but also help pollute the environment.
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FAQs on Do Diesel Engines Have Catalytic Converters
Is a Diesel Catalytic Converter Worth Anything?
The catalytic converter is a crucial component for diesel engines as it helps control the emission release and makes the vehicle legal for driving in the USA. Regarding price, diesel catalytic converters are fairly inexpensive compared to gasoline catalytic converters. Diesel catalytic converters are made of cheaper material, and their precious metals, platinum, and palladium, are also less dense.
Are Petrol and Diesel Catalytic Converters the Same?
The petrol and diesel catalytic converters are almost the same. Both converters come in the same shape, have the same components, and are used for the same purposes. However, the difference is that catalytic converters are placed on the spark-fired gasoline engine, while diesel engines have one downstream of the exhaust manifold.
Does Ford Diesel Have Catalytic Converters?
Yes, Ford has been using catalytic converters since 1976 to reduce air pollution and convert dangerous combustion into harmless chemicals.
What Happens If a Diesel Catalytic Converter Fails?
When it malfunctions, it can release more emissions, reduce the engine performance, and damage the car’s engine. A faulty diesel catalytic converter’s symptoms include poor response when accelerating, strange sounds, and a warning light on the dashboard warning of internal problems. Repair work and replacement are important for the system to operate normally and adhere to the emission standards laws.
How Do Catalytic Converters Improve Diesel Engine Performance?
Although direct engine performance benefits are not primary to its function, and one does not immediately lead to the other, the catalytic converter allows for a further increase in engine performance through more efficient combustion, which, in turn, generates less exhaust that decreases backpressure in the engine as well as maintaining proper flow and proportion of exhaust emissions.
Final Words
The catalytic converter is a blessing for today’s automobile, and thanks to the manufacturer, diesel engines have catalytic converters.
So, the diesel engine doesn’t pollute the atmosphere and damages public health as much as the gas-powered engine does.
Catalytic converters aren’t very expensive and last up to 10 years or over 160,000 km in driving, making those worthwhile components from all around. However, this component requires more maintenance and extra care as it’s attractive to thieves.
I wasn’t sure if diesel engines used them or not, and your post clarified that they do, especially in modern models. The information about how they work in conjunction with diesel particulate filters was particularly helpful. I’m interested in learning more about maintenance for these components.