And where previously, the precision of the settings of the sensitive mechanisms in variable nozzle (or variable geometry) turbochargers was important, it is now absolutely paramount to be accurate.

If you want a turbo to operate efficiently, or in fact at all, you cannot guess at the vane setting position for air flow, or risk catastrophic vibrations with an unbalanced core assembly.

The Australian Mining Review spoke to GCG Turbos director Brett Lloyd to get the lowdown on building and maintaining these highly sensitive set-ups.

According to Brett, the average turbo repair facility will use static rotor balancing, but this fails to pick up the minute sonic imbalances that can happen between the turbine and compressor ends of the turbocharger.

But there is technology available that is so precise it can produce a balance that is comparable to the original manufacturer’s settings.

GCG operates the most technologically advanced turbocharger service facility in Australia, looking after everything from motorbikes right through to 250 tonne dump trucks.

“This technology has really only become available to us in the last 10 years,” Brett said.

“Prior to that everyone was doing the same sort of rotor balancing and field gauge measurements and all that sort of thing, but it’s much more technical than that now.

“If you don’t have this sort of equipment, you’re not really doing justice to a turbocharger rebuild.”

The Right Balance

All objects that rotate around a centre axis have a certain amount of unbalance which creates a resonant frequency (natural frequency of vibration) at a specific rpm.

Traditionally, turbo rotors were balanced at lower speeds, like a tyre shop balances a car wheel.

At low speed, you can achieve a level of balance accuracy because the resonant frequency of the rotor is higher than the operating speed of the turbo.

But as turbos became smaller, rotational speed increased significantly.

A turbo core assembly can reach rotational speeds of more than 230,000rpm (3800 revolutions per second), which means it passes through resonant frequencies within its operating range.

These vibrations, however small, can be magnified enough to damage a turbo or cause catastrophic failure.

To ensure the core assemblies of modern turbochargers do not vibrate excessively, they need to be balanced on a high speed machine which accelerates the core assembly through its full operating speed and measures the vibration as the rotor passes through resonant frequencies.

“A turbo VSR, or vibration sorting rig, basically takes the centre core of the turbocharger, the assembled middle section which includes both impellers, and using a simulated exhaust and compressor housing and sensing, spins the turbocharger at the operational RPM with the oil pressure passing through it,” Brett said.

“It uses exactly the same software, exactly the same parameters, as the manufacturers use.

“Once we’ve finitely balanced it, we take the turbocharger core assembly off the rig and the information is all documented and traceable.”

Brett said supplying each turbocharger’s reports to validate its VSR balance was particularly useful to the mining industry where documentation and accountability is imperative.

Going With The Flow

It takes more than a good balance for a turbocharger to operate at its best.

A turbo needs to be set correctly so that it produces the correct boost pressure as the engine speed and power demand changes.

Variable Nozzle Turbochargers are great at reducing the effects of turbo lag, resulting in better torque and more responsive acceleration especially at low speed.

They work by changing the speed and direction of the exhaust gases onto the turbine wheel.

But when the boost pressure is wrong, both engine performance and emissions suffer, and the OBD (On-Board Diagnostic) system might detect a problem that results in an ECU (Engine Control Unit) shutdown putting the vehicle into limp-home mode.

Flow tests measure and adjust the mass air flow through a turbo.

At GCG, after balancing, the core assembly is put together with its two housings and the turbocharger goes onto a flow bench.

“The turbocharger flow bench can actually measure exhaust pressures, exhaust flow, compressor pressures, and compressor flow, and will allow us to, in the case of an electronically actuated turbo, set the boost pressures, versus the turbo RPM,” Brett said.

“And for a variable vane turbo, you can set the vane into the same position as it would have been when it left the factory.

“Again, the data that’s stored inside our flow rig is the same data that the manufacturers use when they’re building these things in a production facility.”

Pressure Test

The final process finds the turbocharger on a static oil pressure test rig facing seven bar oil pressure to make sure that it’s sealed on both ends and there are no leaks.

“When the turbocharger goes back to the customer, either repaired or a new build, to OEM spec, it meets all the criteria of the manufacturer,” Brett said.

GCG has invested heavily in service technology, installing vibration sorting rigs, turbo flow, benches, oil pressure tests, and numerous electronic turbocharger actuation testing and setting machinery.

And ever-evolving, the company is expanding its DPF (Diesel Particulate Filter) cleaning offering with the addition of ultrasonic and hydrocarbon cleaning machines.

“We’ve identified DPF in the last five years as a definite growth opportunity, with a lot of the current fleet on the road, be it commercial or passenger cars running DPS, and in the next generation GPFs (Gasoline Particulate Filters),” Brett said.

Meeting Demand

There are seven major turbocharger manufacturers in the world, servicing almost 100 per cent of the demand.

Brett said all turbochargers were made by a third party, not the actual vehicle or engine manufacturers.

“We’re representing those manufacturers of turbochargers here in Australia as their authorised distributor and their authorised service centre, which is a little bit different because some people are authorised distributors, but not authorised service centres,” he said.

Providing both sales and service was key to GCG’s success during the uncertainty of the last 18 months.

In fact a major gamble at the beginning of the COVID-19 outbreak paid off for the company, which is now reaping the benefits of being able to supply Australia’s growing demand for turbochargers and parts.

“One of the things we did, rightly or wrongly – my accountant hated me – when COVID first started back in, 2019 and early 2020, was that we actually ramped up inventory,” Brett said.

“We actually said. Well. the world’s going to hurt from this and we’re not going to be able to get anything, so we will ramp up.

“We put about $1.8m worth of additional stock on the shelf just to try to see us through the first part of COVID . . . and it’s probably paid dividends in the fact the market in Australia hasn’t slowed down, it’s actually sped up.

“We found ourselves with good inventories and being able to meet, I would say, 80% of customer demands.”

Keep On Trucking

Although executing deliveries across the country is a little technically challenging at the moment, GCG is still able to manage next day delivery on most items from its two warehouses in Sydney, and is actively looking for a facility in Melbourne.

Fast turnaround is vital for the mining industry, but exchange programs make life easier when breakdowns happen.

GCG has generic exchange programs for common turbos like those in the CAT 15 diesel engine, but also does in-house programs for specific fleet requirements where the customer carries some shelf stock and GCG backs them up with support stock.

Delays are kept to a minimum and the trucks keep trucking.

“They call on their shelf stock, we replenish ours, and everyone is happy, the job gets done as quickly as possible at their time of need,” Brett said.

From the mining industry to the military, from small transport companies to Sydney Ferries, GCG Turbos has been selling and servicing Australia’s turbochargers since 1979.

Family Values

GCG was a family-owned business, founded by Brett’s father Colin.

“We started as a repair facility for turbochargers but back in the late 70s the business evolved from there to being a distribution hub for all manufacturers,” Brett said.

And the company has expanded overseas with a sales and service hub in Japan and recently stepping into Korea with sales; and as soon as restrictions allow, Brett will be there to set up the service division.

“We supply the genuine product, from the same places that supply vehicle and engine manufacturers, but we provide an aftermarket route to trade here in Australia,” Brett said.

“The beauty of it is that we sell the highway product, we have direct access to the manufacturer, we get the best price and you make savings.”

The philosophy of the company is simple, it exists to solve customers’ problems.

“A customer rings us because they need a solution and we need to give them a solution,” Brett said.

“Some things are so old, or something is so unique that we don’t have a new one to sell to them, but our aim is to give the customer a solution and that might be that we need to repair the turbocharger instead.

“Basically we’re available to help any customer that rings us.”

That’s a lot of customers, and a lot of turbos, with GCG supplying and servicing Australia’s mining giants and many capital city transport services. All the busses in Sydney for example, have turbochargers.

“We’re always getting customer feedback, people taking the time to write me an email and thank us for the service we’ve given them,” Brett said.

SOURCE
GCG Turbochargers
P: 1300 TURBOS (1300 887 267); Int: +61 2 9708 2122
E: Sales/Technical – online@gcg.com.au
    Customer Support – online@gcg.com.au
    Workshop/Service – workshop@gcg.com.au
W: gcg.com.au

The post Turbocharged Technology appeared first on The Australian Mining Review.

The report goes on to mention that 20% of all reportable incidents were fire related, and that fire comprised about 25% of all reportable incidents regarding mechanical plant.

Of these, 18% were reported as resulting in damage to plant. Thankfully, there was only one fire-related injury during this period.

The report also highlighted that the most common heat sources for fires are the exhaust system, engine surfaces and turbochargers, while the most common fuel source is hydraulic oil, lubricating oil, fuel and grease.

This reflects a common scenario in mining whereby a combustible oil leaks from a hose or fitting onto or near a hot surface in the engine compartment causing it to ignite.

The report goes on to make several recommendations, specifically that ‘consideration should be given to the consequences of oil and fuel coming into contact with hot engine components as part of a fire risk assessment. Where reasonably practicable, consider shielding to prevent that contact’.

Kool Wrap is a company with a range of products that helps equipment owners adhere to the recommendation made above.

Its products are designed to significantly reduce the incidence of mechanical equipment fires by providing a physical, fire-resistant barrier between the combustible fluids and the hot surfaces by mitigating against various types of heat transfer including convection (where heat is carried by a liquid from one part to another), conduction (where heat is transferred through the object itself), and radiation (where heat is emitted as through the air).

Kool Wrap’s products are made from various types of heat-resistant materials including heat-treated fibreglass as well as new materials such as basalt fibres (known as ‘lava wrap’), which comes with a higher heat rating than fibreglass and has various applications such as inside turbo blankets, heat sleeves, and reflective wrapping.

What Makes Kool Wrap Cool?

The products are hand-tailored and are offered as off-the-shelf items for many common applications or can be customised to suit any application.

The typical composition begins with a stainless steel mesh, followed by a 10-20mm thick section of silicon or needle-felt wool (which provides air pockets responsible for the insulation) held in place by a fibreglass outer layer.

The fibreglass layer is then coated in silicon or teflon (which prevents oil or fuel soaking into the fibreglass) and then it is finally stitched together with Kevlar or fibreglass thread, resulting in a durable, reliable and safe product.

Turbo Blanket Advantages

During the combustion phase of an engine cycle, rapidly expanding exhaust gas is pushed out of the combustion chamber by the upward movement of the piston. The hotter the gas, the faster it expands.

Likewise, if it is allowed to cool (i.e. dissipate heat) then the expansion slows.

It is the rapid expansion of gas that turns the compressor wheel in a turbocharger. The faster the gas expands, the faster the turbo spins.

Normally, heat is dissipated into the turbo exhaust housing and then transferred into the air in the engine compartment, which provides an element of cooling.

However, a turbocharger housing operating under load can exceed 1000°C, which is enough to instantly heat most flammable liquids to flash point, creating an engine bay fire.

By installing a turbo blanket, not only does the insulating properties of the blanket protect other components in the engine bay from the heat emitted by the turbo, but it actually improves the performance of the turbo by ensuring the gas inside the turbo remains hot for as long as possible.

By wrapping the turbo in a Kool Wrap exhaust blanket, the heat is kept inside the compressor housing where it belongs, improving the overall performance.

From a safety perspective, the turbo blanket can prevent serious burns and keep maintenance personnel from contacting these dangerously hot surfaces.

Heat Trick Up The Sleeve

The residual heat emitted from engines, turbos, exhaust manifolds and exhaust pipes can cause damage to pipes and hoses not designed to withstand high temperatures – for example, flexible hydraulic and fuel lines.

By wrapping these lines in Kool Wrap heat sleeves, they are insulated from any conduction or convection within the engine compartment.

Since the heat sleeves are often lined in reflecting aluminium foil (which can handle up to 600°C), radiant heat is also deflected.  Protecting flexible lines in this way not only prevents them from melting and releasing fluid onto hot surfaces but it also delays the rate at which they degrade, for longer service life.

About Kool Wrap

Kool Wrap has been a successful Australian supplier of heat protection products since 1995, originally providing heat sleeves and exhaust lagging to the high-performance car racing industry and then later moving into heavy industries such as the marine sector, farming and mining.

The product range not only includes turbo blankets and heat sleeves but other products such as embossed aluminium heat shield panels, heat reflective tape and other forms of heat protection available on their website.

Fire is one of the greatest hazards in the mining industry, causing substantial damage to plant and equipment, creating significant costs to operators and potentially life-threatening risks to personnel.

It is for this reason that appropriate, fit-for-purpose heat protection devices must be fitted to not only comply with statutory regulations but also to avert the hazards of onsite fire.

More information
Kool Wrap
1300 44 33 34
www.KoolWrap.com.au

The post Keeping Fire Under Wraps appeared first on The Australian Mining Review.

Diesel particulates are associated with a number of serious health conditions and diesel engine manufacturers are required to contain and eliminate those particles in the interests of worker safety and environmental responsibility.

Inside the housing of the filter is a substrate comprising thousands of tiny cells that allow exhaust gases to pass through them but trap the diesel particulate matter.  At various stages of the driving cycle, the on-board computer initiates a regeneration sequence that increases the temperature inside the DPF to 600°C, which converts the diesel particulates to ash.

This non-toxic ash is then small enough to pass through the wall of the filter and out the exhaust system.

These DPFs work well – until they don’t!  Under certain operating conditions and if other engine faults occur, they can become blocked – choking the exhaust system and significantly decreasing engine power and efficiency, while simultaneously sending diesel consumption skyward.

Faults and Failures

DPF Regen is a well established company in Sydney set up to clean, repair and diagnose faults arising with and surrounding DPFs in everything from light vehicles to the largest mining equipment.

The AMR interviewed DPF Regen’s founder and CEO, Frank Spiteri, to shed some light on this very topical issue. Frank has decades of experience with diesel diagnostics and says that the DPF Regen business grew out of necessity from diagnosing and repairing numerous upstream faults that resulted in blocked DPFs.

“Particulate filters block for a number of reasons, most of which stem from upstream issues that corrupt the combustion process and lead to over-rich fuel mixtures that clog the intake, EGR and exhaust systems,” Frank explained.
“You can’t just look at the DPF blockage in isolation, it takes time and knowledge to look at what caused the fouling or damage and repair the original source of the problem or else the filter might block again in a very short period of time.”

One of the most common causes of DPF clogging is a split intercooler pipe or another leak in the intake system of a turbocharged diesel.  An undetected split will often only be visible under boost.  In operation, the escaping intake air does not find its way into the cylinder to match the fuel injected by the ECU.

This results in an overly rich mixture which quickly carbons up the exhaust system, EGR valve and the intake manifold.  The DPF does not fare well either.

Frank can examine the quantity, texture and colour of the soot in the DPF and determine the upstream culprit in most cases.  By alerting the vehicle’s maintenance staff about the problem, they can look for and repair what may seem like an unrelated failure and ultimately save their operation tens of thousands of dollars in repeated unscheduled downtime.

It is not just air leaks that cause DPF clogging.  Over time, intake manifolds become blocked as do the Exhaust Gas Recirculation (EGR) valves that divert soot-laden gases back into the engine as part of their emission control cycle.  Eventually the walls of the valve and the intake manifold runners build p with choking carbon that inhibits the flow of air into each cylinder.

Once again, the ECU cannot measure or counteract this loss of air flow, so it continues to deliver what it calculates to be the correct mass of fuel to each cylinder.  However, because the air flow is reduced, an over-rich mixture is created that leads to DPF blockages.

It is therefore essential to regularly inspect and clean not only the DPF but also the intake manifold and EGR valve to ensure they are not responsible for rapid re-blocking of the filter.

Another cause of DPF blockage is stop/start driving.  Most manufacturers rely on a period of sustained highway (higher speed) driving in order for the ECU to trigger a regen cycle to clean the DPF.  If a vehicle is constantly stopping, starting and operating at low speeds (ie: in town or the CBD) the ECU may never see the correct conditions to initiate the regen, hence the DPF will begin to block and need cleaning more regularly.

Inspection and Cleaning

According to Frank, the first step in any cleaning process is visual inspection.  As mentioned, the state of the DPF’s substrate and the type and quantity of trapped soot can give he and his technicians a very clear picture of why the filter is blocked in the first place.

It is also important to inspect the diesel oxidation catalyst (DOC) which sits inline before the DPF in the exhaust system. This is similar to a CAT for a petrol engine and also helps to reduce the number of particles in the exhaust, before they reach the DPF filter. In most cases, the DOC can be cleaned and restored to full functionality, just like a DPF.

In extreme instances, they DPF can become so blocked that only a small path remains for normal exhaust gas flow.  As all the exhaust is passing through a much-reduced aperture, the associated heat in that area builds rapidly.  At 1200°C the DPF substrate itself starts to melt and once this occurs it is time to replace the unit as it is damaged beyond cleaning or repair.

Allowing a DPF to go uncleaned to the point were temperatures soar to this level can result in catastrophic damage to the entire vehicle from resultant exhaust rupture and fire.  Factory exhaust components are not built to withstand 1200°C.

The cleaning process varies subtly for each application.  DPF Regen use a range of two-part, biodegradable solutions and a specially designed ultrasonic cleaner to break down the carbon and flush intakes, EGR valves, DOCs and DPFs clean – restoring their original flow.  Each solution is designed to tackle a different application and each works at a particular sweet spot of temperature and vibration frequency for optimum cleaning.

Training Centre

Due to the enormous cost of vehicle and machine downtime, Frank recognised that the industry could benefit from education in this area.  Diesel mechanics needed to know how to correctly diagnose the cause of the faults they were seeing, so that the original issue could be repaired once and correctly.

This process of correcting upstream issues ensures the DOCs and DPFs do not become blocked prematurely, leading to costly unscheduled downtime. To that end, DPF Regen also have a training centre for mining staff and other technicians to learn more about diagnosing and fixing engine faults – despite what the scan tool might tell them. Courses are available for all diesel technicians.

The moral of the story is simple: keep diesel particulate filters clean in the interest of worker health and safety, machine uptime, cost minimisation and to prevent total asset loss by fire.  The best way to do that is speak to an expert in the field.

More information:
DPF Regen
02 9774 4142
frank@dpfregen.com.au
www.dpfregen.com.au

The post Regeneration Station appeared first on The Australian Mining Review.