Tag Archives: turbo engines

How does a Turbocharger work anyway?

Sometimes at Western Turbo, we get so wrapped up in helping our customers get back on the road that we forget that education is one of the best things that we can do to help our customers understand when they need to call the best diesel service centre in Manitoba.

Below is a short article on how a turbocharger works and why this is such a key component to the performance of your diesel engine.

The purpose of a turbocharger is to compress the air flowing into the diesel engine, this lets the engine squeeze more air into a cylinder and more air means that more fuel can be added. The engine burns air and fuel to create mechanical power, the more air and fuel it can burn the more powerful it is. In simple terms, a turbocharger comprises a turbine and a compressor connected by a common shaft supported on a bearing system. The turbocharger converts waste energy from an engine’s exhaust gases into compressed air, which it pushes into the engine. This allows the engine to burn more fuel producing more power and improve the overall efficiency of the combustion process. The turbine consists of two components; the turbine wheel and the collector, commonly referred to as the turbine housing. The exhaust gas is guided into the turbine wheel by the housing. The energy in the exhaust gas turns the turbine. Once the gas has passed through the blades of the wheel it leaves the turbine housing via the exhaust outlet area.

Compressors are the opposite of turbines. They consist of two sections; the impeller or compressor wheel and the compressor housing. The compressor wheel is connected to the turbine by a forged steel shaft. As the compressor wheel spins, air is drawn in and is compressed as the blades spin at a high velocity. The housing is designed to convert the high velocity, low pressure air stream, into a high pressure low velocity air stream, through a process called diffusion. In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) that is about 30 times faster than most car engines can go. Since it is connected to the exhaust, the temperatures in the turbine are also very high. Air enters the compressor at a temperature compression causes the temperature of the air to rise it leaves the compressor cover at temperatures up to 200°C. The turbocharger bearing system is lubricated by oil from the engine. The oil is fed under pressure into the bearing housing, through to the journal bearings and thrust system. The oil also acts as a coolant taking away heat generated by the turbine. The journal bearings are a free floating rotational type.

To perform correctly, the journal bearings should float between a film of oil. The bearing clearances are very small, less than the width of a human hair. Dirty oil or blockages in the oil supply holes can cause serious damage to the turbocharger.

Western Turbo repairs turbochargers

Now that you know how a turbocharger works, we will look at some of the reasons in our next blog why turbochargers fail and how Western Turbo diagnoses the problem and decides whether to rebuild or replace.

Insist on OEM

It has been said that stock runs best. Simply put, low grade aftermarket parts are no particular bargain if they don’t perform properly or possess the same degree of longevity that original equipment manufacturer (OEM) parts provide. When it comes to your livelihood, as it pertains to your turbochargers, insist on OEM replacement parts purchased through a reputable source.

Most modern diesel engines are turbocharged. A turbocharger allows the engine’s horsepower and torque to be multiplied through forced air induction. Inside the turbocharger housing is both a turbine and an air pump. Both are driven using the same shaft. Spent exhaust gases, escaping the compression chamber, are used to drive a turbine at very high RPM. As the exhaust turns the turbine, the air pump impeller draws high-volume, low-pressure ambient air into the engine. The ambient air is drawn in through the front air-dam and the intercooler, in order to ensure that a steady source of cooler, denser air is available to the air pump. This additional air induction allows the engine to burn an increased amount of fuel, resulting in more horsepower and torque.

Why buy OEM Turbochargers?

Aftermarket turbochargers aren’t manufactured to the same stringent specifications as OEM one, neither are they made from the same top-quality steel and components. Turbochargers are by nature very powerful, yet they operate under very delicate circumstances. The turbine wheel and housing must be meticulously machined and assembled; tolerances between the impeller and housing can be well under several thousandths of an inch. Extreme temperatures from the exhaust, which drives the air pump, coupled with these very close tolerances demand that the turbocharger be designed, engineered, and manufactured to the most rigid guidelines. You just don’t get that type of quality anywhere but OEM for turbochargers.

The next time that you have a problem with your turbo diesel, trust the professionals at Western Turbo to provide you with quality parts and experienced, courteous service.

North America’s Turbo ‘Revolution’

The change in the market in North America – led by Ford – is particularly remarkable; in 2008, there were no turbocharged petrol engines made in North America, all previous turbo-fitted engines having been imported.

The first North American built turbocharged petrol engine was fitted to the Lincoln MKS which used the first North American EcoBoost engine. This engine has since been fitted to the Ford Flex, Explorer and most significantly the F-series pick-up trucks.

“GM has been somewhat behind Ford in terms of the fitment of turbochargers, but it is slowly going down the same route,” said Ian Henry. “It has already started on this journey – the 2012 Cadillac XTS had a turbo option on the 3.6 litre V6 engine. GM is however also working on improving the fuel efficiency of its naturally aspirated engines and has claimed that it can achieve similar fuel efficiencies gains to those available with turbochargers through other means.”

“The impetus at Chrysler will come from Fiat’s MultiAir programme,” adds Henry.

The CAFE rules announced in 2012 will force GM and Chrysler to accelerate their use of fuel saving technologies such as turbochargers and a large part of the increased volumes which will be seen in the next few years and into the 2020s come from the widening take-up across these VMs, Ford having led the way.

According to just-auto’s QUBE data, North America currently has a turbo fitment rate below 20% but by the late 2020s, if not before, its fitment rate will be much closer to that of Europe, at close to 75%.

How a Turbo Works

Diesel engines are frequently equipped with turbochargers in order to increase their horsepower output, but exactly how is that accomplished? The technology behind turbo charging is known as forced induction. In a forced induction system, the exhaust gas is collected, compressed, and fed back into the engine. This highly compressed air allows for more fuel to be fed into the cylinder as well, resulting in greater power output with each explosion within the engine’s cylinders. As such, turbochargers offer a more compact and efficient alternative for increasing power output as opposed to adding cylinders, which would also increase size and fuel consumption.

Engine exhaust gas spins the turbocharger’s turbine, which then spins an air pump at speeds many times faster than a car engine can rotate, in fact well over 100,000 rpm. Since the air is recovered from the engine exhaust, it is already extremely hot, making for a more efficient burn as well. Normal air pressure at sea level is around 14 psi. A turbo can boost that pressure by as much as 8 additional psi, meaning a potential 50% gain in power, but more typically in the range of 30 to 40 per cent.

Mounted to the exhaust manifold of the engine, the turbocharger is connected to an air compressor via a common shaft, where the exhaust air is compressed before being channelled into the engine cylinders. As the air passes through the turbine, it is moving at a high velocity, but the relative air pressure is low. The compressor then converts this into high pressure, low velocity air. This is what makes it possible for a larger fuel and air mixture to burn at once within the cylinder, versus non-turbocharged engines of similar size. Because the air is converted from exhaust gas that would otherwise have been wasted energy, and is then burned more efficiently in the cylinders, greater engine output is coupled with improved fuel efficiency as well.