Continuing just-auto’s top-level interviews with the component supply base, Matthew Beecham talked with Mark Whitehead, product marketing director engine and sealing, EMEA, Federal-Mogul, about the company’s spark and glow plug developments.
just-auto: Could we start by asking if you could summarize the factors which influence the design of a glow plug?
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Mark Whitehead: When a diesel engine is cold, glow plugs are the first thing that must work. They have to be able to get very hot and survive inside the engine’s corrosive environment for its entire life without loss of performance. And, because drivers want diesel economy, but will not tolerate poor cold-start performance, today’s systems must help to start the engine faster.
For ultra-modern diesels with low compression and high-specific power, heating power is particularly critical. Federal-Mogul’s Champion glow-plugs reach their top temperature of around 1100°C in less than two seconds, making them among the fastest on the market.
Glow-plug design is also important from an emissions perspective. Having a long post-glow time helps to reduce emissions during the powertrain’s warm-up phase.
What challenges can direct injection diesel systems pose for glow plugs?
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By GlobalDataWhen direct injection diesel systems were first introduced, they presented fresh challenges in terms of packaging: engine designers needed to place the injector in the middle and the glow plug needed to get it out of the way. These days, most diesels are direct injection and the industry is relatively comfortable with the solutions. As direct diesel engines develop further, injection and cylinder pressures are on the rise, moving from 180bar towards 230bar in some applications.
We’ve seen rapid start glow plugs emerge on the market. How do you see that technology evolving?
Whereas standard sheath glow plugs have a heating coil whose resistance does not alter even as temperatures increase, quick-start glow plugs’ heating curve does change with temperature. You can use this to reduce the preheating time and to reduce the current as temperatures rise.
To produce even shorter preheating times, you can add further heating and control coils that can produce very short preheating times, but is it the solution for everybody? The answer lies in finding a balance between how rapid customers want the start to be and the price customers are willing to pay. For many mass-market applications, the technology’s additional cost is difficult to justify and the perceived value it creates for customers is harder to define.
In terms of technical specification of glow plugs, what else do you see happening? i.e. longer and thinner plugs?
As diesel engines continue to develop, it’s clear that glow plugs will have to endure higher and higher in-cylinder pressures and this will undoubtedly influence technical specifications.
And, as diesels downsize, it is clear that glow-plugs will have to also. Cylinder head packaging is a real issue in smaller engines.
The big difference will be in the energy-efficiency of powertrain components. Lower-voltage designs that place less demand on the vehicle’s electrical system and battery will contribute to fuel savings. There has been some talk in the industry of integrating glow plugs’ control units into the powertrain management system more closely, but the benefits are relatively slim. Consequently, optimising the mass and the friction between moving parts in the engine is a higher priority for powertrain component suppliers.
What are the factors pushing innovations in spark plugs?
New emissions compliance, fuel economy and CO2 reduction are a major focus for Federal-Mogul in terms of technology developments. In this area, our most important projects are focused on new high performing material and design concepts that support higher specific loads and combustion temperature.
We’ve heard a lot about precious metal spark plugs becoming increasingly popular in Europe, though technically speaking, what are you seeing in terms of copper core technologies?
Precious metal spark plugs have been in the market for many years now, with many OEMs specifying either Platinum or Iridium as the spark surface material. We currently market Single Platinum, Double Platinum and Iridium designs for meeting these extended life requirements.
The duty cycle of engines in Europe is more rigorous than in the North American or Asian markets. OEMs in Europe are now becoming more comfortable with these designs to meet these needs.
New nickel alloys and new copper alloys are all part of a trend to perfect the copper coring of ground electrodes that Champion popularized in the 1990s. As fuel types have changed to include more oxygenated fuel, this has caused an increase in oxidation rates and severity under the most demanding testing. New nickel alloys with higher amounts of Chromium or with Rare Earth additions are being used to control this effect.
In addition, the use of direct injection also has increased the thermal impact on the spark plug. In the past, the fuel was well atomized as a vapour but with direct injection, the heavier concentration of fuel in the spark region has a cooling effect at injection and, in some cases, a hotter burn during combustion. This pushes the thermal envelope in which the spark plug is expected to operate.
Typically the copper core is made of OFC – or oxygen free copper. This is a very “clean” non-alloyed version of copper. Copper is a difficult material to alloy; in most cases, addition of an alloying material has an adverse impact on its properties. Federal-Mogul is seeking materials that would increase its temperature resistance without adversely affecting its thermal conductivity.
What other trends are you seeing in the evolution of spark plugs?
Federal-Mogul is developing high energy spark-plug technologies and enabling advanced combustion concepts like stratified charge, lean burn and diluted charge; and we see significant opportunities in this area.
Direct injection engine designs are requiring new designs to deal with the change in thermal cycle imposed on those spark plugs.
Direct injection and the general downsizing of the automotive engine have a side effect on all components on or within the engine. Engine size and weight reduction will continue to force the reduction in size of spark plugs. Most new engine designs are with M12 thread diameter, replacing the M14 of the last decade. We can expect M10 to supplant M12 in the not too distant future.
Even though spark plug technology is improving, can it really catch-up with engine life? i.e. is a ‘life of engine’ spark plug a possibility?
Engine life has been a moving target for many years, and today’s engine has possibly twice the life of an engine from 25 years ago before it would require major servicing. Spark plugs of today can come very close to meeting this need, however there is no consensus as to whether or not this is a good idea as other engine component failure (such as a fuel injector) can adversely impact the function of the spark plug. Serviceability is still a major requirement for today’s designs. Ultimately, though, the spark plug needs to be part of the cylinder head design for space and packaging efficiencies.
With longer life spark plugs, what is the impact on the aftermarket?
The aftermarket is seeing an impact as more vehicles on the road are using precious metal plugs that last up to 100,000 miles. Due to the longer lasting plugs, the unit volume of plug sales is decreasing in the aftermarket. As the average age of vehicles on the road has been decreasing, so too has the demand for copper spark plugs while the need for iridium spark plugs has been increasing. As a precious metal spark plug, iridium plugs are more expensive to manufacture than copper plugs. Consequently, overall spark plug market sales have decreased somewhat.
Looking at the distribution channels in Europe, what are the big changes you are seeing at the moment? Is there anything in particular in the change or structure that is driving that? How do you see these channels developing?
The Block Exemption Regulation in the European Union has a certain impact on the overall market environment in the automotive industry, allowing suppliers like Federal-Mogul to distribute their own parts into the market. As a result, the vehicle manufacturers implement strategies and operations to enter the independent sector of the automotive aftermarket to gain back market share, especially on older models and fleets.
Within the independent aftermarket, Federal-Mogul recognizes a general trend in the structure of the wholesale sector to consolidate purchase in co operations or through mergers and acquisitions to generate higher volumes and more purchase power versus the parts industry. These co operations or acquisitions are taking place on an international level, which has a certain effect on tactics and strategies on the industry side.
In satisfied markets like the main Western European markets, the traditional distribution (wholesaler) is seeking to grow and to generate additional market share. Two trends that Federal-Mogul recognizes are that traditional distributors are trying to enter the end-consumer market through acquisition of service centers or by implementing their own workshop systems. They also try to introduce their own private labels as mid-range or entry-level offerings to become more competitive and to be independent from industry brands.
As a supplier to these distributors, Champion offers a variety of packaging (trade packs, volume packs, 2-packs, 4-packs) to meet the varied market demands. In addition, Federal-Mogul has introduced and will continue to introduce innovative products, such as our compact spark plugs, to extend the Champion brand and increase its recognition in the market.
What’s happening to brand names in the market place? Is the power of brands increasing or diminishing with the changes? Anything in particular in the change or structure that is driving that?
Federal-Mogul markets a broad portfolio of leading brands that are designed to solve problems, facilitate installation and improve safety, durability and vehicle performance. Our brands are well respected and carry tremendous value for Federal-Mogul and its customers. Through global market insight, supply chain expertise and world-wide brand and product line management, aftermarket customers worldwide benefit from our extensive OE technology and manufacturing expertise.
