Power steering (power steering) versus electric power steering (EPS). We weigh all the pros and cons

You can determine which unit is installed on the selected brand of car without the help of the seller. To do this, you need to look under the hood of the car. If you find a tank there with a corresponding pictogram depicting a steering wheel, it means that in front of you is a car with power steering. It is into this tank that the power steering fluid is poured. If there is no reservoir, and the steering wheel turns freely, then this means that the car has an ESD installed.

Healthy! In some cars, the power steering fluid reservoir is located in the bumper and the device is a hybrid of electric and hydraulic power steering. But such cars can be counted on one hand. For example, several Opel Zafira models are equipped with just such “hidden” power steering units.

To figure out whether electric power steering or hydraulic power steering is better, it’s first worth talking about the features and differences of each of these systems separately.

Power steering

Power steering is more common today, unlike the electrical system, which is just gaining momentum. The hydraulic booster consists of complex components - low and high pressure pipelines, belts and other elements through which fluid circulates, poured into a special tank connected to pumping equipment. As soon as the driver turns the steering wheel, a number of processes occur. First, high-pressure fluid is supplied through the distributor into the steering mechanism, after which it is pumped into the hydraulic cylinder, thereby creating pressure that affects the piston. As a result of the displacement of the latter, the degree of effort that the driver applies to turn the steering wheel is reduced. When moving along a straight path, the power steering fluid flows back into the reservoir. As you can see, this is a rather complex closed fluid circulation system, in which many elements are involved, each of which can fail over time.

Electric power steering

The design of the electric power steering is much simpler than that of a hydraulic booster. By and large, this is a small electric motor, a control unit and two sensors: torque and angle of rotation. A device mounted on the steering rack or column itself reads information about which driver is transmitting the steering angle. In this case, torque is transmitted using a torsion shaft, which is built into the steering unit.

If we talk about how power steering differs from electric power steering, then in the first case, the force applied to the steering wheel is reduced due to pressure and circulating fluid, in the second, the information is converted thanks to electrics, as a result of which the wheels turn slightly. In this case, the electronic power steering unit analyzes the data and, based on it, calculates how much current the electric motor will require. Thanks to this, when parking or sharp maneuvers, the greatest effort is produced from the EUR. During slow turns, the electric power steering reduces torque and is practically not used.

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If we talk about the advantages of electric power steering over power steering, then it is worth noting the following advantages of the electric amplifier:

It takes up minimal space.
During operation, the EUR consumes energy only at those moments when it is in use. The power steering works constantly as soon as you start the engine.
The electric booster operates uninterruptedly both in severe frosts and in hot weather.
Since the EUR consists of fewer elements, it is more reliable, since it does not require constant maintenance and repair.

However, electric boosters have their own characteristics that confuse some drivers. Therefore, let’s try to figure out which system performs better in management.

Characteristics of power steering

This type of amplifier appeared much earlier than the electric one. Power steering is a vehicle steering element that operates using a liquid drive. Despite the growing popularity of electric power steering (VAZ is also equipped with it), power steering is the most common amplifier. Structurally, this unit contains a hydraulic pump. It is driven by the crankshaft via a belt drive. The reader can see what it looks like in the photo below.

Below we will consider the algorithm of operation of this system.

Signs of power steering wear

Power steering is not only comfort, but also additional safety (especially if emergency steering is necessary in an emergency situation). Therefore, you should pay close attention to the first signs of a faulty power steering:

Vibrations appeared on the steering wheel;
The steering wheel began to turn with difficulty;
After completing a turn, the steering wheel is in no hurry to return to “zero”;
The power steering pump hums when the steering wheel is turned;
Fogging (traces of oil) on the power steering reservoir;
Traces of hydraulic oil after parking;

How does power steering work?

As we noted earlier, this unit operates on the basis of hydraulic fluid. So, during rectilinear motion, the fluid circulates in a circle. That is, it passes through the channels from the pump to the tank. However, as soon as the trajectory of movement changes (the driver turns the steering wheel), the liquid enters one of the cavities of the distribution sleeve. Depending on the rotation of the steering wheel, it goes to the left or right side. From another cavity, the liquid is drained into the tank. Thus, the piston ensures the movement of the steering rack mechanism. The force from turning is transmitted to the rods.

This is how the direction of movement of the car changes. The highest pump performance is observed when the steering wheel is turned in place (that is, when parking in a limited area). However, the system is driven by a belt drive from the crankshaft. But its speed during parking is minimal and close to idle. Accordingly, the force generated by the pump is insufficient to turn the steering wheel. What to do? Shouldn't you apply gas until the cut-off? The manufacturer took this point into account. Therefore, in such situations, the electronic control unit sends a signal to additionally open the valves. So, a larger amount of fluid enters the power cylinder of the steering rack. Therefore, “on the spot” it will be very easy to rotate the steering wheel. But don’t get carried away - remember that at this moment the pump is working at full capacity. Frequently turning the steering wheel all the way while parking reduces its service life.

Overview of the ESD system

Younger, in comparison with the power steering, is the electric power steering. The main difference between the EUR and its predecessor is the absence of liquid, which takes on the main working role. Owners of cars with electric power steering now do not need to monitor the oil level in the system and do not need to worry about replacing it. Instead of working fluid, the electronic power steering control unit takes on all the responsibility. Thanks to the built-in sensors and presets in the ESD system, the driver can set the steering “stiffness” he needs for the most comfortable ride. So, you can set the steering wheel to rotate softly when driving at low speeds, and a little harder at high speeds, so that the car is more stable on the highway and does not “walk” from side to side. It is quite difficult and not cheap to install something like this on power steering. In addition, unlike the power steering, which consumes energy constantly, the electric steering wastes electricity only when the steering wheel rotates.

Summarizing the advantages of EUR, the following points can be highlighted:

easy adjustment of the EUR for a specific vehicle speed;
reliability of the system, due to the absence of liquids and rubber pipes that are destroyed by temperature changes;
lower maintenance and repair costs compared to power steering.

Among the shortcomings of the ESD, the only thing that can be noted is the occurrence of sensor malfunctions, which, fortunately, happen extremely rarely.

Thus, we can summarize that now the EUR is less common than the power steering. However, the fact that the electric booster is more advanced than the power steering is an indisputable fact. Therefore, if you have the opportunity to choose between power steering and electric steering, choose the latter.

Design features, operating principle

Today, there are two types of layout of this unit. In the first case, the force of the electric motor is transmitted to the rack. In the second - on the steering wheel shaft. The most popular is the first type of electric amplifiers. It is also called electromechanical. The design uses two gears with parallel drive.

The EUR is combined in one block with the steering mechanism. Electric motor type – asynchronous. How does this mechanism work? Torque is transmitted directly to the rack from the electric motor. There are also two sections of teeth on the rack and pinion mechanism.

The EUR system consists of many sensors. These include a steering angle element, a torque sensor, crankshaft speed and the speed of the vehicle itself. The mechanism closely interacts with the ABS control unit and the vehicle's ECU.

After processing information from the above sensors, the embedded program generates a corresponding signal to the actuator. It is an asynchronous electric motor.

Electric amplifier operating modes

The steering can operate in several modes:

Active return of the steering wheel to the middle position.
Turning the car at high and low speed.
Supports mid-position steering wheel.
Turning the car under normal conditions.

As in the case of power steering, the wheels are controlled by the steering wheel. However, here the force is transmitted through the torsion bar. The twist of the latter is measured by the corresponding sensors (angle of rotation, torque, etc.). So, the force from the engine is transmitted to the rack. Then, through the steering rods, the drive wheels turn in the desired direction. The operation of the unit does not depend on the position and speed of the crankshaft.

Electric power steering

Electric power steering circuit

In electric power steering (EPS), additional force when turning the steering wheel is created by an electric motor.

Design and principle of operation of electric power steering

The main elements of the electric amplifier include:

electric motor
torsion bar and steering column shaft
steering mechanism (gearbox)
steering wheel position sensor
torque sensor
electronic control unit

When the driver turns the steering wheel, the torsion bar begins to twist. The torque sensor measures this twisting, determines the torque value from it and transmits this information to the control unit. The latter processes data from the power steering sensors and correlates them with the readings of other vehicle sensors (speed, crankshaft revolutions, etc.).

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The control unit calculates the force that must be applied to help the driver turn the steering wheel and gives the appropriate command to the electric motor. The latter acts on the steering column shaft or steering rack, thereby facilitating rotation of the steering wheel.

Advantages and disadvantages of EUR

Electric power steering rack

The main advantages of an electric amplifier include:

fuel efficiency - the EUR does not take power away from the engine and turns on only when the steering wheel is turned
reliability due to the absence of a hydraulic system
compactness and ease of maintenance
ability to adjust steering characteristics and settings
possibility of implementing automatic vehicle control

Despite numerous advantages, EUR also has some disadvantages. These include:

low power while maintaining minimal overall dimensions and cost
possibility of overheating and temporary failure under unfavorable driving conditions
expensive repairs

However, it should be noted that in the design of modern cars, the electric power steering is gradually taking first place, displacing the power steering.

Today, electric power steering is actively replacing hydraulics, as they have much better characteristics and relieve drivers from such manipulations as replacing power steering fluid. In addition, they perform better on the road and have excellent performance. Therefore, if you are purchasing a new foreign car, then preference should be given to electronics; in the case of a VAZ, you should really evaluate the capabilities of the car; perhaps it is better to use hydraulics.

Advantages of power steering

So, which is better - power steering or electric power steering? Both of these nodes have their pros and cons. But first, let's look at a hydraulic drive system. Power steering is a cheaper mechanism to manufacture. Accordingly, the cost of the car is an order of magnitude lower.

Plus, cheap power steering repairs (if the issue does not concern the rack). When disassembled, the power steering pump for the ninth Lancer costs 2-3 thousand rubles. Moreover, it is sold already assembled, with a pulley (but without a belt).

Cons of hydraulic booster

When considering the question: which is better - power steering or electric power steering, it is worth mentioning the disadvantages. There are many more of them. The first disadvantage is the size of the structure. Power steering is a rather cumbersome thing. The pump, pulleys, reservoir and belt take up a lot of free space. Plus, it’s difficult to repair the timing belt. To replace the belt on it, you first need to remove the pulley from the power steering. Fortunately, the power steering pump remains in place.

If you choose between what is better - power steering or electric steering for your car, it is worth considering the issue of servicing this unit. And there are some nuances here. The power steering system requires periodic maintenance. If you do not change the fluid or belt on time, the power steering will require repair.

It is also unacceptable to use the mechanism for a long time at high loads. Because of this, the liquid boils quickly. The steering wheel should be turned all the way for no more than five seconds.

The next drawback is the dependence of the system on engine performance. The unit conceals the engine power because it takes part of the force from the crankshaft through a belt drive. The same can be said about the air conditioner, which also operates from this pulley. Therefore, due to the bulkiness of the design and other shortcomings, power steering can now only be found on SUVs and commercial vehicles. But why can’t EUR be installed in trucks? You will find out this a little later.

Pros and cons of EUR

In a hurry to answer the above question, let us immediately note the shortcomings of the EUR. “Kalina” is equipped with such a mechanism due to its small wheels. What's all this for? The fact is that the electric amplifier is not capable of generating the required torque to turn large wheels (especially under a load above). Because of this, the unit is not used on trucks and vehicles weighing more than two tons.

This is the main drawback of the EUR. Which is better - power steering or electric power steering? To answer this question, consider the advantages of the latter. There are an order of magnitude more of them than shortcomings. So, the mechanism does not take power away from the engine. At high speeds the steering wheel is quite informative with it. The system does not require periodic maintenance, because there is no liquid or pumps. The only thing that fails over time is the rolling bearings in the electric motor. But in order to get them out of working order, you need to operate the EUR for a long time and diligently. A VAZ equipped with such an amplifier responds to the steering wheel much faster. After all, the signal from the sensors is transmitted at lightning speed. And the pump needs time to generate the necessary pressure and transfer liquid from one circuit to another.

Also, answering the question: “Which is better – power steering or electric power steering?”, it is worth noting the compactness of the latter. The EUR does not take up much space in the engine compartment (since it is mostly hidden in the cabin). Accordingly, getting to any node will be much easier. And through the computer you can configure the operating mode of the amplifier. Also, the system does not boil if you hold the steering wheel in the extreme position for a long time.

Which is better, power steering or electric power steering?

Among modern cars, it has long been impossible to find those that are not equipped with various types of power steering.

All cars are equipped with power steering or electric power steering . Many drivers, especially beginners, at the stage of choosing a car, often wonder what is better: electric or power steering .

And to answer it, you need to know the difference between power steering and electric power steering .

First of all, you need to understand that any type of power steering is installed for the purpose of making it easier to maneuver the car.