A year on from the Volkswagen emission scandal, speculation is growing about the life-span of diesel engines, fuelled by rumours that Norway is planning to ban all diesel engine passenger cars by 2025 – with other European countries potentially following suit. So do diesel passenger cars have a future? And how realistic is it to carry out such schemes? What impact will the elimination of diesel passenger cars have on the turbo aftermarket?

CO₂ emissions impact the atmosphere and are continuously reported as a key contributor to climate change. The more recent focus on passenger car emissions has been accelerated by the Volkswagen scandal of 2015. The aftermath revealed there was a huge difference between the results of OEM laboratory tests and real-world driving emissions.

As a result, New European Drive Cycle (NEDC) legislation has been revised in line with real-world driving conditions. This has highlighted that European institutions are trying to get a better understanding of emissions from diesel and petrol  cars.

Improving air quality

In a bid to improve air quality in Norway, leading political parties have called for a ban of the sale of all diesel passenger cars by 2025. In contrast, the UK government has set policies in place to push low emission vehicles – which includes diesel passenger cars. It would be much more difficult to implement an outright ban in the UK. The population is considerably larger, with a larger diesel passenger car parc.

Despite a push on low emission vehicles, air pollution remains a hot topic in the UK. As the country prepares to leave the European Union there needs to be clarity on what is going to happen to current air pollution policies.  When the government pushed diesel cars in the early 2000’s, they knew there would be a negative effect on air pollution. But, they believed it would be vastly outweighed by the reduction in greenhouse gas emissions.

As technology advances, zero air pollution and zero emissions should, in hindsight, become easier to achieve. The current political focus appears to be on rectifying the current situation through the regulation of existing technology such as diesel particulate filters (DPF) or selective catalyst reduction (SCR) technology.

Benefits

There are many benefits to diesel engines. It has been well publicised that today’s diesel passenger cars are the cleanest ever, with high tech filters capturing 99% of particulates. Since the introduction of the Euro emission regulations in 1992 diesel particulate matter has reduced significantly and is currently at the same level as petrol applications at 0.005 g/km. NOx emissions have also significantly reduced and are just 0.02 grams behind petrol passenger cars.

Overall, diesel engines are more efficient to run and contain more energy per litre than petrol engines. Diesels have led the way in turbocharger technology, with petrol applications now quickly following suit. Despite these positives, the Norwegian national parliaments are committed to the ban of diesel passenger cars. They currently lead the way in electric vehicle sales due to tax exemptions, free charging points and parking benefits.

The ‘demonisation’ of diesel

Since the Volkswagen scandal diesel passenger car sales have seen a downward trend; the Group’s Audi division has seen their market share drop from 69% to 67% in the first four months of 2016. Consumer research suggests the scandal has been a major contributing factor in this downturn. Buyers are seeking out petrol applications that match the performance and fuel efficiency of their diesel counterparts, as well as hybrid and electric vehicles.

Although diesel is often in the firing line, it isn’t just these cars that create the problems; it extends to vans, buses, taxis and petrol engines too. For example, diesel road traffic is responsible for about 40 per cent of London’s NOX emissions. Government policies to reduce carbon emissions have indirectly promoted and incentivised the use of diesel over petrol. Which as lead to an increase in the number of diesel cars on the road.

With this in mind, countries calling for a ban of diesel cars need to consider other contributors to vehicle air pollution which are varied. Any new policies should consider the impact to these groups and the effect they will have on the automotive industry as a whole.

In terms of the turbo aftermarket, there are still plenty of turbochargers that will need repair. Due to the adoption of turbos on petrol applications, this will continue for many years to come.

Küresel otomobil endüstrisi, Volkswagen emisyon skandalını takiben artan bir inceleme ile karşı karşıya olduğundan, bu vahiyin doğal olarak piyasamızda bir etkisi olacak, ancak ne ölçüde?
Okumaya devam et “The Future of Diesels”

Parts Design Improvements -There has been much discussion within the automotive repair industry about the differences between using OEM parts and the aftermarket equivalent repair parts. In this article, with a focus on turbochargers; we explore the benefits associated with using high quality repair parts and why such parts can actually improve a turbo repair.   Okumaya devam et “Melett Parts Design Improvements – Better than OE?”

Today’s automotive repair industry is faced with an overwhelming range of repair parts. Amid claims of exceptional quality at extraordinarily cheap prices, here Martyn Howorth, Sales Director, Melett Ltd., explores the reasons why some turbocharger components are offered at such low prices, and what the real cost of these low quality parts means to the repair industry.

Okumaya devam et “Is the Price Right?”

Air Flow Rig – There has been an ongoing debate for many years between the original turbocharger manufacturers and the turbocharger repair industry, over whether a turbo can be repaired.

This debate has been raging for over 10 years. Some OEM turbo manufacturers pulled out of the repair market around 2004; at this time their argument was that most repairers did not have the correct specialist balancing equipment for the new higher speed turbos.

Over the last decade, vehicle technology has continued to improve to reduce emission levels in order to meet the Euro 4, 5 then 6 regulations. As a result of these changes, engine and turbo technology has increased in complexity. As well as the settings and control of advancements, such as the Variable Nozzles, have become more critical to the correct operation of the turbo. This is now presenting new challenges to turbo repairers as the correct setting of the turbo on later models, now requires further specialist equipment in the form of an Air Flow Rig.

What is a Variable Nozzle Turbo?

When a turbocharger is matched to an engine, the Engineers have to balance the low speed response with high speed efficiency. The variable nozzle (also referred to as a variable geometry), is designed to change the exhaust gas inlet area with the engine speed to closely match the desired boost requirements of the engine. For low speed response, the nozzle vanes move to the ‘closed vane’ position to reduce the nozzle area – this increases gas speed through the turbo giving improved response at low engine speeds – similar to squeezing the end of a hose pipe to make the jet of water more powerful. As the engine speed increases, the actuator moves the nozzle vanes to the fully open position to maximize the exhaust gas flow.

Vane Setting Accuracy

When the first variable nozzle turbos were launched, it was a step change in turbocharging technology.  Air mass sensors and ECU’s were programmed to manage the whole engine system, however relative to the current engines, tolerances for acceptable air flow were set quite high. When setting up a new turbo, vane setting positions are set using accurate air flow equipment, which ensures that the ‘minimum vane opening’ position is set to allow a specific mass of air flow through the vanes. If the vanes are too closed, this can cause choking of the engine and overspeeding of the turbine. If it is set too large, the turbo will have too much ‘lag’ and not respond as well as it should.

Traditionally, turbo repair workshops did not use an air flow rigs to correctly set the flow. The actuator position was set based upon an accurate measured position of the actuator arm. This produced acceptable results and allowed the repairers to keep on repairing.

In reality, this method of setting the vanes can produce quite large inaccuracies in the flow of air. The actuator arm measurement is set against a cast finish on the bearing housing, the position of which is not accurately controlled during manufacture. However, as the engine would accept quite a large tolerance of air flow, the repaired turbo still performed well compared to the broken turbo which it replaced, so the vehicle owner was still happy with the results. On older turbo repairs, the variable nozzle position had to be a long way out before the performance was unacceptably affected or for the ECU to flag a problem.  From an OEM perspective, this is not acceptable and is the reason for their lack of support of repairing.

The need for accurate air flow setting of turbos was well understood by reputable repairers, and hence some quality repairers developed their own air flow equipment to accurately set their turbos, resulting in a reduction in warranties and the ability to build on their reputation as a quality repairer.

Today’s Turbos

In more recent years, as engines have improved to meet tighter Euro emission regulations, the control over the whole air / fuel system has improved dramatically. Many premium brand vehicles have moved to electronic actuation which gives positional feedback to the ECU. Some more advanced turbo controllers now sit within the CANbus talking directly to the injection system and air mass sensors, to respond more quickly to engine demands. For these turbos, the settings are either correct and accepted by the ECU –  or not which results in warning lights, limp home mode or refusal to start.

As more of the Euro 5 compliant vehicles enter the aftermarket, problems will arise and for some turbo models, we have already reached the point where flowing the turbo is a necessity and only possible by workshops who have the correct equipment. However, this will naturally mean that older turbos also become more widely repaired using air flow equipment, which will bring further improvements to the market.

Making the Right Choice

Traditionally, in the turbocharger aftermarket the customer had a choice between a new OE turbo and a remanufactured turbo. Over the past 10 years the turbo repair market has changed significantly with the number of new repairers entering the market and the number of suppliers of parts. What we now have is three tiers, a new OE turbo, a high quality remanufactured turbo repaired using quality parts and the correct equipment, and a poor quality repaired turbo, using inferior quality low cost parts. There will always be a market for all three options depending upon the vehicle owner’s requirements.

It is important that garages understand that there are different levels of quality for repaired turbos and therefore a different level of associated cost.  When outsourcing turbo repairs it is crucial to consider the real cost of replacing a turbo and to educate your customer about the different options and associated risks for going lowest cost vs paying a little more for quality, so they can make informed decisions. Who pays for the time to fit the second replacement? What if it damages other parts of the engine?

Many turbo specialists already have a flow rig and are repairing turbos to an excellent standard. It is a fact that warranties are reduced when turbos are repaired using quality parts as well as the correct repair equipment.

More Information

To request further details about Melett, including information about where you can find your local quality turbo repair specialist, email: [email protected]