For passive regeneration to take place, the temperature in the DPF needs to reach approximately 300°C, which is only possible during relatively fast driving. Additionally, the injector cost is exponentially higher. Therefore, car manufacturers implemented a solution to force the exhaust temperature to rise to around 600ºC and clear out the DPF. Not to many around with the Diesel engine, here is a gorgeous one owner, no accidents really really clean GLK 250 AWD , comes very well equipped with panoramic sunroof, heated leather seats, winter and summer rims and tires, power seats, power tail gate, summer and winter matts, three key, manual and so much more. However, it is a permanent fix that has a minimal impact on the engine performance. Now, if you plan to keep the car for a few years and you’re not very lucky, you may need to replace all the components I mentioned in this article within the few years of owning the car. Everything is governed by computers more powerful than what was necessary to put people on the moon. The price above is what independent car repair shop will charge you. Another model from the Volkswagen Auto Group shows up here in the form of the Audi A3, and it bears the same 2.0-liter,… If you are doubtful, get expert advice. If you’re unlucky, or you didn’t do your research prior to buying the car, you may be looking at an additional £500 to deal with the swirl flaps. Other factors that are bad for the DMF is urban driving, jerky gear changes and aggressive takeoffs from a standstill. At some point, it will be so clogged that it will put the car into “Limp Home” mode and illuminate the “Check Engine” light. This website uses cookies to improve your experience while you navigate through the website. This is indicating your DPF is full and the engine computer was not able to complete the regeneration. The EGR in petrol cars is a good thing. How is it supposed to work reliably when it’s full of soot? Replacing the EGR valve costs somewhere between £300 and £600 at an independent repair shop. Swirl flaps are also used in petrol cars. For example, a compression ratio of 18:1 means that the volume of gas is reduced 18 times when the engine piston is at the top of its stroke. Ford Aspire. Affects: petrol and diesels - but more diesel cars will be affected (Euro 6 is the minimum standard for diesels; Euro 4 for petrol) 2023. Today, we’ve got fuel injection systems that run at pressures high enough to cut through things. These filters need to be unclogged … Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website. One could say that modern diesel engines are crippled by the emissions control devices. Swirl flaps live in the air intake manifold. And with many journeys limited to two kilometres at this time, it means many people are driving in exactly that way. As a car owner, it used to be the norm to schedule in an oil change every 3,000 miles. In some cars, the EGR valves are a recurring problem due to poor design and may need replacing every 50,000 miles. For the sake of example, let’s say that you bought one with 150,000 miles on the clock, and you are planning to keep it for three or four years. An example of unnecessary car maintenance for the low-mileage driver is changing the engine oil too often. Keep in mind that 100,000 miles is a very rough estimate. This creates a vacuum in the intake manifold because the engine is trying to suck in more air than it is allowed to. If you take the car to the dealership, you can add 50% or double those figures. This should prolong the EGR valve life expectancy noticeably. Passive regeneration is a slow oxidation process and it may not be enough to fully clear the soot, and not all cars are capable of passively regenerating anyway. CON: Although diesel fuel is considered more efficient because it converts heat into energy rather … The manufacturers have been struggling to meet them ever since, which made diesel engines less reliable and even more complex. Let’s say that the fuel injector can only fire 1000000000 times (I made this number up). This is the source of the higher maintenance cost of diesel engines, especially high-mileage engines. Also, the amount of exhaust fumes that gets recirculated is a lot smaller. At least as far as reducing throttling losses is concerned…. All modern petrol and diesel cars are fitted with an Exhaust Gas Recirculation (EGR) system. 24 kmpl. Also, a tightened NOx emissions limit meant that some cars had to be fitted with NOx traps, which proved to be not as effective as expected (VW emissions scandal). As you can see, it’s very important to know what to expect maintenance-wise when you buy a used diesel car. The EGR system in petrol cars is usually reliable because the exhaust gases contain a fraction of the particulate matter as compared to diesel engines. The vehicle's computer determines when to regenerate the DPF based on the amount of soot/particulate matter in the filter. The ones that don’t have springs, rely solely on the DMF for damping. These cookies will be stored in your browser only with your consent. A new one from a car manufacturer can cost £1,000 and £3,500, potentially wiping out the cost savings associated with driving a diesel. The mechanism that adjusts the swirl flaps may fail. If you drive well below the average mileage each year, then although the car may be above average at purchase, it could be considered below average at sale. However, if you drive a car with a DPF mostly in the city, well, you bought the wrong car. It’s not uncommon for a DPF to cost €1500 for the part alone excluding the labour for fitment.. © RTÉ 2021. The side effect of higher injection pressure and multiple-injection strategy is shorter fuel injector lifespan and lack of tolerance to poor fuel quality. Euro 5 (new cars registered from 1 January 2011) – the use of diesel particulate filters became mandatory. Its job is to smooth out the jerky nature of the engine’s power delivery. The other major improvement in diesel injector technology is the ability of piezoelectric and solenoid injectors to deliver multiple injections per combustion cycle. A forced regeneration is initiated through a diagnostic tool when the car is parked. Some of the components in these systems are not very reliable. It's also one of the easiest things to … In some cars, it is possible to convert from a dual-mass flywheel to a solid flywheel. The total cost of all this stuff would be close to £3500 using the average prices. The whole point of swirl flaps is to reduce emissions. Too much air won’t hurt (to a certain point at which the engine blows up). They may develop air leaks around the shaft that holds them (some designs only). Even when the engine is capable of running lean, the emissions of nitrogen oxides (NOx) can go through the roof. A butterfly valve called the throttle plate is used to control the amount of air entering the engine. Also, nitrogen oxides are linked to acid rain, while soot is linked to smog. Improvements in fuel injection technology are what made modern diesel cars less diesely (for a lack of a better word). Summary All of the above suggests that buying a diesel car for mainly city driving is not a great idea. Your email address will not be published. Yet, car manufacturers grab every advantage to get their cars through emissions testing. On a final note about compression, forced induction (turbocharging and supercharging) increases the effective compression ratio. If you drive primarily in the city without regular longer trips, the DPF lifespan can be halved. js = d.createElement(s); js.id = id; Pay for them in cash (if at all possible) to avoid incurring interest payments on a loan. There is also the option of injector reconditioning for about half the price of a new set. Trade-in, One Owner, Non-smoker, Local, Low Mileage! It’s cheaper and some people choose to do so to avoid recurring problems (popular decision among fleet owners). The particulate matter needs to be burned off before the DPF becomes full. High RPM torque and power output are not affected unless the swirl flaps don’t work properly or carbon build-up becomes severe. This category only includes cookies that ensures basic functionalities and security features of the website. If the DPF warning light does not go out or is accompanied by an Engine Management Light, bring the vehicle to your nearest main dealer immediately. If you liked this article, please share it with your friends! However, when they are designed well, they aren’t as problematic. And here’s more on the topic of progress. Ex Demo & Low Mileage Used Cars Browse fantastic deals on ex demo and low mileage used cars from a huge range of manufacturers and dealerships. Diesel cars are being demonised, but are they really as bad as they're being made to seem? The main problem with dual-mass flywheels is that the improvement in comfort and noise is often so small that it doesn’t justify the cost of the DMF and the reduction in reliability as compared to using a single-mass (solid) flywheel. Welcome to the space age. The need for regular regeneration cycles is precisely why particulate filters are a terrible idea in cars that are driven in cities. Unfortunately, I can’t say the same about the diesel injection system or the auxiliary parts that reduce emissions. If the car model you are looking to buy is fitted with “high risk” swirl flaps, you should take some precautions, like replacing the intake manifold with a new one. Its function is to feed the exhaust gases back into the engine to reduce emissions of nitrogen oxides. It’s a low mileage car, though. Nevertheless, diesel fuel injectors are precision devices, and they are not nearly as simple as they used to be. These cookies do not store any personal information. This raises the temperature in the DPF to circa 650c and burns the trapped soot/particulate matter to ash. If you look after your diesel car well, and 80% of your driving is on the motorway, there’s no reason why a DPF or other components should not last 200,000 miles. Basically, if you drive your diesel car primarily on the motorways, you should have no problems with the diesel particulate filter. By following this logic: Will an injector that fires 8 times per combustion cycle have a 4 times shorter lifespan than an injector that fires 2 times per cycle? Everything was purely mechanical and such engines were still used in passenger cars in the 1990s. They close at idle and low engine speeds to create a swirl in the air going into the cylinders. As you now know, diesel engines generate a lot of particulate matter, which isn’t friendly to moving parts like the EGR valve. Bought a new car, wondering why is the mileage so low in a Brand New Car as against claimed Mileage by Company in between 20 Kmpl to 25 Kmpl. This leads to a more complete combustion, more power, better efficiency and less smoke. Meáin Náisiúnta Seirbhíse Poiblí na hÉireann. Most diesel car owners are wasting money - because they don't do enough miles to get the benefit from their engine, according to … Explore Diesel cars for sale as well! Joking aside, if you buy a modern diesel car in poor condition or you’re simply unlucky, you may have to pay through the nose to keep the car going. Mileage is considered high or low relative to the car's age. The advantage of the FAP is that it handles city driving better than a typical DPF because it can regenerate at lower temperatures. In a way, actively regenerating the DPF is like bombing for peace (or f***ing for virginity). The main problem that can arise in these circumstances is usually with the diesel particulate filter (DPF). It may get technical at times. There is generally less wear and tear with low mileage cars, as long as the car has been cared for properly. Changing the DPF isn’t difficult or time-consuming, just the particulate filter itself can be quite expensive. Here’s a quick summary of what you should take away from all this: Modern diesel exhaust system is a sophisticated chemical reactor. The combustion in diesel engines occurs as soon as fuel is injected. I will explain in a moment. Essentially, petrol engines are constrained by the air-fuel ratio without employing clever injection strategies in direct-injection engines. Better solvent come at a cost at this point stuff would be surprised how much the gas, piston... Managed to survive this long being dangerous to the metal, you may get 150,000 miles out the! Better word ) tool when the DPF as soot trap between 100,000 150,000... Power and refinement made direct injection turbo-diesel cars more popular still has original... As dampers in cars with particulate filters are actually quite effective, and it is sensitive poor! Option is illegal because it increases emissions the topic of progress the atmosphere the manufacturer, bought! 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