Which is better, power steering or electric power steering?
What are the main differences between a GUR and an EPS
In modern cars, turning the steering wheel is done with maximum ease. In vehicles that were manufactured before 1950, this was not provided. Therefore, drivers had to exert some effort to make the wheels of the car turn in a particular direction.
Which unit is used to make the car steer comfortably? Different car models use one of two types of units: the GUR and the EPS. These are specific mechanisms that have certain technical characteristics but differ in their operating principle.
Which unit provides comfortable driving?
Principles of EPS
First let's understand what is meant by the GUR. It is a power steering system, with the help of which the steering of the car is greatly facilitated.
The GUR is a closed hydraulic system that consists of several important elements. These include a hydraulic pump of gear or gate (vane) design, which includes a pressure reducing valve, a reservoir for hydraulic fluid and a steering rack. In addition, a power hydraulic cylinder is used. It transmits force to the steering rack. The hydraulic cylinder can be designed either in the rack housing itself or as a separate device that transmits the force to the steering rod, as for example on the CitroenSaxo or Peugeot106.
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All elements of the mechanism are connected by rubber reinforced high-pressure tubes. They contain hydraulic fluid. It is usually ordinary mineral oil ATFATF (AutomaticTransmissionFluid).When the driver turns the steering wheel in any direction, a certain line opens. The hydraulic fluid pressurises and helps the piston to move and push the steering rack. In this way, the force required to turn the steering wheel is reduced many times over.
In the past, GURs were installed exclusively on lorries. Later, the mechanisms began to be placed on passenger cars, because with power steering the driver does not get tired even during a long journey.
The driver is not tired even when travelling for long periods of time.
Principles of EPS
What is electric power steering? It is a unique system that does a great job of reducing steering effort. It consists of a steering shaft, a motor, an electronic unit and sensors for steering torque and steering wheel speed.
The operation of electric power steering is quite simple. It consists in the fact that during the rotation of the steering wheel torsion of the torsion shaft is performed. It fulfils the role of a tracking device. This action is instantly recorded by a non-contact sensor. On the basis of this information, the intelligent electronic unit makes the necessary calculations. It determines the optimum compensating force and signals the electric motor to turn the steering shaft in the same direction as the driver.
GPS and EPS
Till recently there was a tendency that motorists when buying a car favoured a car with hydraulic power steering. Allegedly a real «masculine» car should work only with a GUR. In fact, this is a stereotype, which has absolutely no grounds. The EPS system is not worse than the hydraulic power steering system in terms of the quality of its tasks, and in some aspects (fuel economy, diagnostics capability, etc.) it even surpasses it.
Hydro power steering is a time-tested system. It has significant advantages. It is a reliable design that meets strict quality standards. The hydraulic system is characterised by versatility. It is used with equal success on passenger cars, on lorries, on minibuses.
The electromechanical system also has good features:
- compact dimensions;
- ease of use;
- only switching on when the steering wheel is turned;
- simplicity of construction.
Also the main advantage of EPS is its excellent compatibility with the electronic systems of the car. Given the popularity of electric cars, it is safe to say that electric power steering is the future.
Minuses of GPS and EPS
Even the most perfect mechanisms have disadvantages. This also applies to the auxiliaries under consideration. The key disadvantage of GUR is that the system uses hydraulic fluid. It is necessary to control its level and replace it in time. Unfortunately, official representatives do not always share information about the frequency of oil replacement in the hydraulic system, but as our experience shows, you should change the oil in the hydraulic system at least every 50 thousand kilometres of mileage. Moreover, it is not too costly operation – the total amount of oil in the hydraulic system is about 1 litre. Another disadvantage is that the GUR operates in a constant mode. This contributes to increased fuel consumption.
What can be said about EPS? The minus of the electromechanical system is obvious:how to check the EPS without installing it on the car? This is due to the fact that the system consists of complex elements. To exclude breakdowns, you need periodic diagnostics of the electric power steering. So you can avoid unpleasant situations. Another disadvantage of EPS is the small power of the mechanism. Therefore, it is not used in the production of off-road vehicles and lorries.
There is no unambiguous answer to what system is better. Both types of auxiliary systems are characterised by reliability in operation. It is up to the driver to decide which one to favour.