The Advantages and Disadvantages of a Common Rail Diesel Engine

Common rail diesel engines are the modern version of diesel engines. Most of the diesel-powered vehicles you see today will have common rail technology in it. If you’re unfamiliar with common rail, it is a term that defines the fuel injection system used for these engines. Common rail uses a high-pressure rail to deliver fuel to each solenoid valve. This is opposed to the traditional direct fuel injection system of using low-pressure pump nozzles to deliver fuel while producing more emissions.

The Top 5 Advantages

The common rail diesel engine allows for better emission control and consumption of fuel and power. In other words, common rail diesel engines can deliver more power to the vehicle while consuming less fuel and producing fewer emissions. For these reasons, it complies with government regulators who want to put a cap on the volume of carbon emissions produced by a vehicle.

Below is a list of the 5 main advantages.

  1. Lower Emissions – One of the reasons that common rail diesel engines were invented by vehicle manufacturers was because the government created stricter regulations on carbon emissions. Remember when big diesel trucks used to release a lot of black smoke into the air? You hardly see that anymore because the common rail diesel engine is designed to reduce those emissions. This is better for the environment and is one step closer to fighting global warming.
  2. More Power – Studies have shown that vehicles with a common rail diesel engine will produce 25% more power than a traditional diesel engine. This means the overall performance of the diesel engine will be improved.
  3. Less Noise – Direct fuel injection systems were known for being noisy while driving. The common rail will reduce a lot of the noise that you might remember hearing. This makes it a more pleasant driving experience for you and those around you on the road.
  4. Fewer Vibrations – There used to be a lot of vibrations felt in traditional direct fuel diesel engines. Now those vibrations have been reduced with the common rail direct injection system.
  5. Better Mileage – Since the common rail diesel engine provides more power, that means you will get better mileage on your fuel. As a result, your fuel economy will be better as well. This means less money spent on fuel when you’re on the road.

The Top 3 Disadvantages

With all the advantages of the common rail diesel engine, there are some disadvantages as well. Although there are fewer disadvantages, they may affect your decision of whether to purchase a common rail diesel engine-powered vehicle or not.

Below are the top 3 disadvantages.

  1. Expensive Vehicle – Vehicles with a common rail diesel engine are going to be more expensive than those with the traditional diesel engine. If you’re working for a company that supplies you with the vehicle, then it is no sweat. But if it is a personal vehicle, then you may not want to spend the extra money.
  2. Expensive Parts – Since the common rail vehicles are more expensive, you can expect that replacement parts are going to be expensive as well.
  3. More Maintenance – Common rail diesel engines will need more maintenance than a traditional diesel engine. Even if you do the maintenance yourself, it still takes more time, effort, and possibly expense.

Read also: Full Floating Axle Working Principle, Advantages and Disadvantages


The common rail diesel engine is certainly an advancement in diesel technology that will eventually replace the traditional direct injection system altogether. Perhaps when this new technology becomes more common in every diesel-powered vehicle, then it will become less expensive. Until then, you will be making an investment into an engine that gives you better performance, better mileage, better driving experience, and promotes an environmentally friendlier agenda.

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