We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Automotive

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is the Use of Urea in Diesel?

By Paul Scott
Updated: May 23, 2024
Views: 38,446
Share

Urea is used in several new diesel powered vehicle models as a post-combustion emission suppressant. The rationale behind the technology is the control of nitrogen oxide (NOx) concentrations in the exhaust gases of compression ignition (CI) engines. NOx is a natural byproduct of CI systems and a major contributor to air pollution. The value of using urea in diesel powered vehicles exhaust systems stems from the chemical's ability to convert the majority of the NOx component in the gases to harmless nitrogen and water. This use of urea in diesel vehicles is typically achieved by injecting a fine spray of urea into the exhaust catalyst, thereby effectively neutralizing a substantial percentage of the harmful NOx content of the exhaust emissions.

Compressive ignition systems produce temperatures and pressures far higher than those in spark ignition gasoline engines. These conditions produce high levels of nitrogen oxide in the exhaust gases of diesel engines. Global concerns regarding the growing negative impact NOx emissions have as air pollutants have lead many countries to introduce stringent NOx control measures pertaining to new diesel powered vehicles. These controls have seen an increasing use of urea in diesel engine systems; several top automobile manufacturers include urea injection as a standard feature in their new diesel models.

The use of urea in diesel engines centers around the chemical's natural breakdown of hazardous NOx into harmless water and nitrogen. Most new diesel burning cars feature multistage exhaust emission management systems which separate soot and NOx from exhaust gas progressively and with the urea injection phase being one of the last steps. The urea introduction takes place in the system's selective catalytic converter (SCR) section where a thin jet linked to a separate urea tank sprays a fine mist of the liquid into the NOx rich exhaust gas. The exhaust gas then released into the atmosphere is almost completely soot and NOx free.

At present, several automobile manufacturers are claiming NOx conversion rates of 80% or more using urea in diesel vehicles. These reductions will certainly have a positive environmental impact but may add significantly to the cost of driving a diesel vehicle. These systems may also add inconvenience to the diesel driving experience because many new diesel vehicles only allow a limited number of starts if the urea tank is depleted before cutting out completely and stranding the motorist. Fortunately, most new urea injection diesel models feature notification and warning systems which flag the driver if the urea level becomes low.

Share
WikiMotors is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon287579 — On Aug 26, 2012

@anon287406: You must have visited your friendly German auto dealer. They are notorious for unearthly overcharging customers for simple maintenance items. I once got charged $75 for rotating the tires when it was in their shop under the frequent warranty work required.

By anon287406 — On Aug 25, 2012

The total bill just for adding AdBlue? A stunning $316.99. We were down to 18 percent full on the additive at 16,566 miles. It took 7.5 gallons to fill the tank, costing an eye-opening $241.50 for the fluid alone. The labor to add the fluid plus tax accounted for the rest. None of this was covered by the warranty… At the current rate and cost of consumption, just the AdBlue itself (without the labor, which would probably be included as part of the routine service) would cost $1,457.80 for 100,000 miles of driving. That's a lot of money, knocking about a third off of your fuel savings vs. buying a GL450 V8.

By anon205088 — On Aug 11, 2011

I've been driving a new diesel that uses Urea and it does not add significantly to the cost of driving. It uses about 2 gallons per 5,000 miles, and costs about $3.00 per gallon.

Share
https://www.wikimotors.org/what-is-the-use-of-urea-in-diesel.htm
Copy this link
WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.

WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.