What is an actuator in a car, how to check and adjust it

Actuator in the car: what is it, how to check and adjust it

To increase the power of the motor without increasing its volume, the exhaust gas is actively used. It gives additional energy by directing it under pressure to the vane mechanism so that it spins out and captures more air.

The air flow is then fed into the engine cylinders and helps refine the fuel. One of the auxiliary parts in this process is the actuator. What it is and how to fix the various problems associated with it, we will discuss below.

How the turbine guard works

As we said before, the exhaust gas and air that the blade mechanism (or simply the turbine) captures is under pressure. Sometimes it gets too high, and it has to be reduced by discharging the excess gas through a special valve – that’s what an actuator is, and it’s just necessary in a car with a turbocharged engine.

The principle of the actuator is to react to an increase in the engine turbine speed – the valve opens and releases some of the exhaust gases, which, as you remember, help the blades to unwind. Thus, the turbine doesn’t get enough motive power, and the pressure is relieved without reaching the critical point.

All this happens automatically: the designers calculate at what intensity of gas force on the turbine, it is time to release the revolutions, and it is when the set value is reached that the valve is triggered. Now you understand how the actuator works and why it is called the turbine protector.

If you simply use your car without changing anything in it and have it serviced in time, you don’t have to worry – the actuator is already tuned and will work fine. For those who are keen on tuning, especially turbo and engine functionality, there are a number of risks that can be avoided by learning how to tune the westgate properly.

Common Westgate Malfunctions

The most common problems with the actuator are as follows:

The actuator gear lugs, which are responsible for activating the valve, break;
the electric motor with which the valve blades open fails to operate;
the diaphragm that keeps the westgate airtight gets worn out;
Electronic components which tell other parts that it is time to open the valve, malfunction;
Rust forms at the piston rod.

Signs of malfunction are quite diverse:

As the car accelerates, blue smoke can be observed coming from the exhaust pipe. As soon as the car begins to drive at a steady speed, the color of the exhaust gas changes to normal.
There is constant black or white smoke, regardless of whether the speed changes or not.
Car accelerates slower than before.
Oil consumption increases, its leakage can be seen on the turbine blades.
The engine is very noisy, and a grinding noise can be heard.

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How to check the turbine actuator

To check the actuator, it is best to remove the entire turbine and make sure there is no rust. Note the following:

The metal rod should move freely, deflecting no more than 10 mm and making no clangs or other strange noises.
The diaphragm should be resilient, intact and not deformed. Slide the rod all the way up, insert the plug into the hole associated with the cuff – if the seal is still intact, the rod will not move out of place. To be sure, it is better to wait a few seconds so as not to lose sight of even the smallest hole.
The electronic elements of the actuator are checked at the service station – this requires a number of special tests.

All defective parts are subject to mandatory replacement.

How to adjust the turbine actuator

Now let’s figure out how to adjust the actuator, so that the turbines work productively. This is worth resorting to if the compressor knocks when the engine stops or changes speed. Most likely, the metal rod is a little loose. Also, with adjustments, achieve more performance.

Before you tune the actuator or do any other manipulation of the turbine, think about whether you have a good enough understanding of their construction. If you have any doubts, it is better to ask an expert.

If you just want to increase the pressure, you can replace the spring or loosen the end of the regulator. In this case, the valve will open at higher revolutions than before, but you should not be overzealous.

Read also: What should be the pressure in the cooling system, how it is created and what to do in case of deviations from the norm

If the impact will be exorbitant and the actuator will not work, it can damage the engine and put it out of operation. A solenoid is also used to boost the pressure, which gives a false reading of the current airflow head. This is put in front of the westgate so that the air gets there first.

Adjusting the actuator starts with removing the turbine – you need an adjustment nut. There are also cars that provide access to it without removing it. If you screw it in a little tighter, you will adjust the stroke of the rod.

You need to do the following:

Remove the bracket from the metal rod and loosen the nut with a #10 wrench.
Counterclockwise tighten the adjusting screw – you can do this with something handy, such as a pair of pliers. The sash should close. Tap on it lightly – you should not hear a deep ringing sound.
Make a couple more turns counterclockwise.
Put the bracket back in place and tighten the adjusting nut back on.
After installing the turbine, start the car, try to accelerate and decelerate – you shouldn’t hear any knocking, clanking or grinding.

But this is not the end of the supercharger setup – you need to make calibration, that is, establish the dependencies between the readings of the device and the size of the input value.

This requires special programs like Cummins INSITE and diagnostic software. With their help you will make sure that you have done everything correctly.

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Why the actuator is the brain of the turbocharger and how it works

Turbo engines are becoming more and more popular today, which means it’s a good time to talk about how turbocharging works and what turbine actuators are, which are rightly called the brain of the turbocharger. And at the same time, it’s time to find out if actuators can and should be repaired.

How they came up with the idea to pump air into an internal combustion engine

As internal combustion engines have progressed, engineers asked themselves a question: how, without breaking the stoichiometric ratio of the air-fuel mixture, to burn more fuel at a time, thereby increasing the engine torque without increasing its displacement? And they formulated the answer: it is necessary to supply more air into the engine cylinders by increasing its density.

Initially, the Roots Brothers’ positive displacement superchargers were used for this purpose in automotive internal combustion engines. The principle of the volumetric blower, or compressor, is very simple: rotors driven by the engine crankshaft via a belt or gearing “scoop up” ambient air and supply it to the engine cylinders under excess pressure.

The main disadvantage of such a supercharger is the energy-consuming mechanical drive and, as a consequence, a significant loss of engine power and increased fuel consumption.

The first production cars with compressors were the Mercedes 10/40/65 hp (pictured) and Mercedes 6/25/40 hp (both 1921-1924). Source: János Tamás / Wikimedia Commons

An alternative in 1911 was offered by the Swiss Alfred Buchi, who patented a supercharger, driven by the engine exhaust, i.e. without using a mechanical drive. According to the patent, this device made it possible to increase the engine’s power by 120%. This was the beginning of the turbocharger era.

However, at first they were mainly used in ships and airplanes, but not in cars, because due to the massiveness of the turbines at low speeds, there was not enough exhaust gas flow to spin the heavy impeller to the required speed. In addition, there was a delay in turbine response at variable engine speeds (so-called turbolag).

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Gradually, these problems were solved. The first production turbocharged cars were the Oldsmobile Jetfire and Chevrolet Corvair Monza Spyder, produced in 1962. In the seventies, following the success of turbocharging in Formula 1, and the global oil crisis, the Porsche 911/930 followed, with the world’s first Twin Scroll turbine – with two radial channels for the exhaust gas flowing to the turbine. This solution helped to reduce the effect of turbo lag – the lack of a rush of traction at low revs.

In 1978, the first passenger car with a turbocharged diesel engine, the Mercedes-Benz 300 SD, was introduced. And in the following decades, turbocharging technology became truly mainstream, allowing for smaller, more powerful and simultaneously more fuel-efficient engines that emit less pollutants. Turbocharging systems have evolved to be more reliable, more compact, and with significantly reduced inertia.

Variable geometry turbochargers, also known as variable geometry turbochargers (VGTs), are becoming more common in turbo diesel designs – discussed below.

How a turbocharger works

Structurally, a turbocharger consists of a turbine, whose blades are spun by the flow of exhaust gases, and a centrifugal compressor, placed with it on a single shaft, which pumps air into the cylinders. The air flow is sucked in axially, accelerated to enormous speed, and then expelled radially through the spiral volute of the diffuser.

Sectional view of the turbocharger: the “hot” turbine part on the left and the “cold” compressor part on the right. Source: Quentin Schwinn (NASA) / Wikimedia Commons

In variable geometry turbocharger supercharger systems, it is possible to change the size of the exhaust gas channel cross-section as well as the angle of its entrance to the turbine wheel. This is necessary in order to regulate the speed of the compressor and to protect both the engine and the turbocharger itself against overloading, especially at high speeds.

For this purpose, a mechanism consisting of synchronously rotating blades (marked with number 1) is placed at the turbine inlet. Source: Ton1 / Wikimedia Commons

The PCA mechanism is actuated by an actuator – a pneumatic or servo actuator – on the commands of the engine control unit, which makes sure that in all driving modes the turbocharger works optimally.

Thus, it is the actuators that are the main protectors of the turbine and the engine.

What is an actuator and why is it the brain of the turbine

There are several basic types of actuators. Most of the current ones are electronically controlled. Not only do they function as pressure limiters, but they can also flexibly regulate the optimum pressure in part-load modes. For this purpose, readings from various sensors which monitor the engine operation are used. Electronic actuators also help to realize a short-term “overdrive” or “overboost” in hard acceleration mode.

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The electronic actuator consists of a servo drive with a gearbox and a position sensor as well as a programmer board, combined with a unit cover. Source: Sergey Samokhin / ABS-Auto

The design of a modern actuator includes a servo drive with a gearbox and a position sensor and a so-called programmer – the “brain” of the device. Such a complex design allows the actuator to respond to the engine ECU commands at lightning speed, flexibly regulating the work of the turbocharger, ensuring precise metering of air supplied to the engine cylinders and guaranteeing compliance with strict environmental standards.

Fix or replace?

Damage to the PSA mechanism that occurs during vehicle operation can also damage the actuator itself. Such causes include lever sticking, coking or other damage to the nozzle apparatus from particulate matter. This causes mechanical damage to the servo drive gearbox, which uses plastic gears in its worm mechanism. Jamming of the gears increases the current consumption and can damage the electric motor and the programmer as a result. Such problems cause incorrect operation of turbine components and appear in the form of errors, jerking when driving and engine switching to the emergency mode.

Most often, when such problems occur, the turbocharger is replaced as a complete unit. And this is not a cheap pleasure. Besides, the car “hangs up” in the service for a long time, which is expensive for both the client and the workshop – in fact, several other cars can be serviced for this time.

The solution is to replace the actuator, which is much less expensive for the car owner than buying a new turbocharger assembly. And from the workshop’s perspective, replacing the actuator offers the opportunity to increase the number of vehicles serviced per unit of time.

Wear and tear on actuator components. On the left, the plastic gears in the gearbox are chipped and frayed, as a result of the increased effort to move the blades of the PCA mechanism. On the right picture on the left you see the worn out programmer board, which shows signs of thermal stress through color changes and localized charring. On the right you see the new board. Source: Sergey Samokhin / ABS-Auto

Can a worn actuator be repaired? You will find many examples of repair on the Internet, including here on DRIVE2. It is not necessary to go far for examples: drivers suffered with actuators here, here, here, here, here, here and with a more professional approach – here. Amateurs open the body, change the pinions on non-original, soldered tracks … Unfortunately, most often such repairs leave without attention other components of this complex electromechanical device – O-rings, parts worm and spur gear, needle bearings and their seals, thrust washers, the output crank and connecting rod and so on. Recalibration of the actuator may also fail to meet factory specifications, causing increased fuel consumption and emissions. Thus, any such repair will only have a short-lived effect that will sooner or later lead to the replacement of the turbocharger assembly.

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The original dealer diagnostic equipment (left) has more capabilities to diagnose actuators compared to the “multi-brand” equipment (right). Source: Sergey Samokhin / ABS-Auto

That is why the optimal way is to replace the turbine actuator with a new one, moreover, taking into account the high complexity and importance of the device, from a large and well-known manufacturer.

It is recommended to replace the actuator after diagnosing the turbine itself for various defects.

What to replace?

A large number of state-of-the-art engines from various manufacturers already factory installed Hella actuators, regardless of the turbine manufacturer, which can be BorgWarner, Honeywell, MHI or IHI-CSI. Hella has been manufacturing actuators of various types since 1999 and is a leading European supplier of the said products. On the present moment more than 10 million Hella units have been produced. Now you can buy them at official dealers of Hella.

Among the widespread series of turbo engines in Russia originally equipped with Hella actuators we can single out the following modifications: – BMW: B47 TOP Long BG3. 3 LP GTD2, N57 TüTL R2S, N47 TUE OL, B47OL D EU-VI, N47 D20 T1, N47 C16, N57 TU, N47C20 IHI; – Nissan: X61B, YD25DDTi, X81C; – Hyundai / KIA: R2. 2L EU5, D4HB; – Ford / PSA: Puma 2.2, LYNX C1; – Audi: W36 EMC CyRc; – MB: OM642.

That is, if we talk about the most popular models, these are Peugeot Boxer, Citro¸n Jumper, Ford Transit Custom, BMW 1, 3, 5 series and X3, Nissan Navara (Frontier) and Pathfinder, Hyundai Santa Fe, Kia Sorento.

To correctly identify the actuator with the factory calibration corresponding to your engine, check the markings (as shown by user Yuriy39region ):