The automobile industry is nothing if not filled with plenty of choices for buyers. Today, we have the luxury of choice for our next car to run on petrol, diesel, CNG, or even electricity. However, a Diesel engine is something many people feel very attached to and comfortable with. That’s because today’s diesel engines are not like the ones we used to see in the past. We commonly associate diesel engines with explosive but clunky performance, high running noise, plenty of vibrations, and questionable environmental impact. However, today’s diesel engines have something called Common Rail Direct Injection (CRDi). This fuel injection method changed how Diesel engines behave, and we’re here to unmask the magic behind such a revolutionary system. Here’s everything you need to know about CRDi Diesel engines.
What is a CRDI (Common Rail Direct Injection) Engine?
Despite what the name might suggest, a CRDi engine is not necessarily a different kind of engine. The denotation of CRDi in an engine’s name simply states that the engine in question uses the CRDi fuel injection system to send fuel, in this case, diesel, into the pistons for combustion. Components like a common rail, an injector, and an ECU (Electronic Control Unit) are some of the key components in a CRDi diesel engine. Also, a CRDi Diesel engine features a high-pressure fuel pump, as opposed to a low-pressure fuel pump found in older diesel engines without the CRDi fuel injection method. Much like how the use of turbochargers in cars originated from aircraft engines, the CRDi also first saw deployment in a different class of vehicle.
British engineering company Vickers first developed a common rail injection system. It pioneered the use of common rail in various submarine engines. Although Germany first attempted to use a CRDi engine for road vehicles, Japan put the first mass-produced CRDi engine to use for road vehicles, in this case, heavy-duty trucks, in the mid-1990s. However, today, anyone can have a slice of that pie since there is a plethora of consumer cars with diesel engines that use modern CRDi methods, albeit sharing the same principle.
How does a CRDI Engine work?
Collecting Fuel Inside The Common Rail
As we mentioned, a regular diesel engine uses a low-pressure fuel pump, while a CRDi diesel engine houses a high-pressure fuel pump, which is controlled by the ECU. The fuel pump then takes diesel from the fuel tank and stores it in the common rail at a very high pressure. The pressure inside the common rail ranges from 1,000 to 2,500 bar (14,500 to 36,250 psi). Once the diesel is inside the common rail, that is when the Electronic Control Unit’s (ECU) functionality comes in.
Dynamic Fuel Injection
The optimal amount of diesel to inject inside the cylinder varies with various scenarios. The engine’s RPM, throttle position, heaviness of the load, the density of the air, and the required power by the car all factor in when trying to determine the correct value of diesel to inject into the chamber. Hence, the ECU takes these factors into account and controls the flow of the diesel to mix with the air. Since the common rail holds pressurized fuel inside it, the engine gets a lot of smaller droplets inside the cylinder rather than a few big ones.
Optimized Combustion
These small droplets of diesel then explode with the help of compression, or sometimes a glow plug, to give the engine the desired power. It is easier for the refined fuel spray to mix well with the air for a better, more efficient explosion. Compared to that, the older diesel engines have had to deal with a slightly lumpy fuel. This would cause the engine to either run rich or lean randomly depending on the fuel-to-air ratio, which results in some of the undesirable traits of a diesel engine, such as rough power delivery and high noise levels.
Advantages of CRDI Engine
Since the CRDi Diesel engines are more popular now compared to regular ones from the past, it is clear that there are plenty of reasons why engine makers switched to the common rail injection method. Here are some advantages of using a CRDi diesel engine over other diesel engine options.
Better Performance
As we mentioned above, the older diesel engines had to deal with lumps in the fuel, or rather chunky fuel, now and then. Such a condition resulted in the engine delivering an inconsistent performance up to some degree. It was not a deal breaker, but once you experience the stable performance of a diesel engine that uses a common rail injection method, it’s hard to knowingly go back to the old ways.
Enhanced Fuel Efficiency
The steady power delivery also meant it would be easier for the car’s ECU and transmission to turn the wheels more efficiently. Rather than the ECU having to treat each cycle as a worst-case scenario, it can better manage the power coming out of a CRDi diesel engine through the transmission, depending on the throttle and current speed. And as we all know, better management leads to better efficiency.
Refinement
Not having to deal with an inconsistent power delivery is something the ECU is grateful for, but it’s not the only one that benefits from it. The constant power delivery also helps keep the engine running in a more refined manner. Such refinement then helps the driver and passengers inside the car feel more comfortable and, in some cases, even luxurious while the car is running. An unrefined engine may be tolerable for short rounds inside the city, but it can make a big difference in longer road trips with fewer breaks.
Engine Durability
The aforementioned increased refinement of the engine, thanks to the stable fuel spray, would also help the engine increase its lifespan. The engine is a mechanical component, first and foremost, and it suffers from wear and tear like all other mechanical parts. The increase in refinement means a smoother operation and less wear and tear on the engine’s body. As a result, CRDi engines can claim higher durability over older ones in the long run.
Lower Emissions
The people outside the car benefit from a CRDi diesel engine just as much as the people inside it, though indirectly. A diesel engine is famous (or rather infamous) for it’s not-so-great emissions and a cloud of black smoke coming out of the tailpipe. What a common rail does is make sure that the diesel engine’s operation is smoother than ever, which leads to better atomization of fuel and better air-fuel mixing to efficiently burn fuel. This helps it spew out fewer emissions than before. Not only better for the driver but better for the environment as well!
Disadvantages of CRDI Engine
Like all good things, the CRDi diesel engine isn’t perfect either. For all the advantages it provides, it has some flaws as well, which should not go unnoticed. The advanced tech, use of an ECU, and having a high-pressure fuel box linked to the engine give it an upper hand in terms of performance and efficiency. However, it’s a double-edged sword, and the other side contains some complexities and obstacles both before and after a common rail injection diesel engine is made. Here are some disadvantages of a CRDi diesel engine.
Higher Production Cost
Building a simpler diesel engine may not yield as good a result as a CRDi diesel engine in terms of performance, but at least it does not dig too deep into the pockets of both the engine makers and consumers. A CRDi engine requires more parts to run compared to a regular diesel engine. Moreover, some of those parts include the likes of computer chips and pressure sensors. As a result, the production cost of a CRDi engine is higher when compared to a regular one. A costlier engine means a costlier car, and that’s not exactly a tempting situation for people.
Complicated Assembly And Repairs
The more advanced a piece of machine gets, the more complicated it gets to build, manage, and repair it in the long run. Apart from resources, a CRDi engine extracts a heavier toll on the manufacturers in the assembly line, especially when mass-producing such engines for consumer cars. Moreover, if some fault or issue occurs on a CRDi engine, it takes a highly skilled or specialized worker to be able to properly diagnose it and take the necessary steps to resolve it. Finding such a mechanic can be troublesome if one is in a remote location.
Louder Noise At Higher RPMs And Not As Eco-Friendly As You Think
No matter what technology one uses to smoothen or refine a diesel engine, it is, at the end of the day, a diesel engine, after all. So, there are bound to be some primary characteristics still attached to it. One of them is a louder engine noise as the RPMs climb up. Furthermore, the implementation of CRDi and its refinement causes the diesel engine to achieve the high rpm even faster and produce the noise even further. The emissions are not as high as a regular diesel engine, but it still exhales some harmful stuff like NOx (Nitrogen Oxide) and PM (Particulate Matter).
Popular CRDI Diesel Cars
If you prefer a Diesel car and like what the CRDi engine offers, here are some cars that come with such an engine.
Name | Price |
Kia Sonet | Rs. 9.95 to 14.89 Lakh |
Mahindra Scorpio N | Rs. 13.76 to 24.54 Lakh |
Hyundai Venue | Rs. 10.59 to 13.34 Lakh |
Mahindra XUV700 | Rs. 14.47 to 26.57 Lakh |
Hyundai Creta | Rs. 12.45 to 20.15 Lakh |
Tata Nexon | Rs. 10.99 to 15.49 Lakh |
Tata Harrier | Rs. 15.49 to 26.44 Lakh |
Mercedes-Benz GLE | Rs. 90 Lakh to 1.08 Crore |
The automobile industry has seen the implementation of CRDi in diesel engines for a while now. The application of such technology ranges from passenger cars, commercial cars, and off-road vehicles to marine vessels.
Hyundai is one of the most popular car manufacturers in the country, and one of the reasons behind it is the impressive fuel economy its cars deliver, even with the Diesel engine. The Hyundai Venue and Creta come with the 1.5-litre U2 CRDi diesel engine. The same goes for the Kia Sonet and Seltos since they share most mechanical components, including the engine with their Hyundai counterparts. Unfortunately, Hyundai and, by extension, Kia, have discontinued the diesel engine options for their cars this year, so you will have to make do with the ones that were sold up until now.
Tata, on the other hand, continues to sell cars like the Altroz and Nexon with CRDi-equipped Diesel engines as an option. The Harrier and Safari are available only with a Diesel motor right now, and they use CRDi as well. Some of Mahindra’s most popular cars, like the Scorpio N, XUV700, and Thar, use a CRDi diesel as well. Even German automaker Mercedes-Benz made sure to give the GLE’s diesel engine a CRDi treatment as well. It goes to show how popular and beneficial a CRDi diesel engine can be in certain situations.
Summary
So there you have it, a complete guide on that is a CRDi diesel engine and how it works. CRDi is an evolutionary step in the diesel engine’s history, and a lot of people can enjoy optimal and efficient performance from their diesel cars thanks to it. Although it comes with its complexities, and maintenance and treatment might be more difficult than a regular diesel engine, a CRDi ensures that the engine is overall a better option in the long run. Perhaps that is why many popular car manufacturers in the country and all over the world opt to use a CRDi system for their diesel engines.
FAQs about CRDI Diesel Engines
Is the maintenance for CRDi diesel engines more expensive?
Yes, the complex mechanism of the CRDi engines requires specialized components and skilled mechanics to work on them. These factors can lead to an increase in the bill.
Is there a difference between CRDi and Direct Injection(DI)?
Yes, a direct injection fuel system sends the fuel directly into the engine’s ignition chamber without any middle component (hence the name). A CRDi system sends the fuel to a pressurized common rail first, which then sends the appropriate amount of fuel into the chamber.
Are CRDi diesel engines common these days?
Yes, you will find that a majority of modern diesel engines use the CRDi fuel injection system, including some of the most popular cars like the Hyundai Creta, Mahindra XUV700, and Tata Nexon.
Are CRDi diesel engines more eco-friendly?
Yes and no. Compared to a traditional diesel engine, a CRDi diesel engine produces fewer emissions. However, it still produces some harmful substances like NOx (nitrogen oxides) and PM (particulate matter).
What are the main components of a CRDi diesel engine?
Some of the main components of a CRDi engine include a fuel injection pump, a high-pressure pipe, an injection nozzle, and an ECU.
