Modern car driving cannot be imagined without the comfortable control provided by the steering system. Unlike older models, where turning the wheels required significant physical effort, today even massive SUVs can be controlled with one finger. Special mechanisms known as power steering are responsible for this comfort. Understanding what types of these devices exist helps not only in choosing a car, but also in proper operation and timely diagnosis of faults.
The evolution of steering systems has gone from the simplest mechanical racks to complex electronic systems with adaptive control. Power steering is a device that reduces the force required by the driver to turn the steering wheel using power from the vehicle's engine or electrical current. There are several main types of such systems, and each of them has its own unique characteristics that affect the behavior of the car on the road. Understanding their differences is useful for every car owner who wants to understand the technical part of their vehicle.
In this article we will take a detailed look at what power steering there are, how they work and how they differ from each other. We will analyze the advantages and disadvantages of each design and discuss reliability and maintenance issues. Whether you own a classic sedan with hydraulics or a modern electric car, knowing about the types of boosters will help you feel better about your car and avoid costly breakdowns.
Hydraulic power steering (power steering)
The most common and historically first mass system is hydraulic power steering (Power steering). The principle of its operation is based on the circulation of liquid under high pressure, which is created by a special pump. This pump is driven by a belt from the engine's crankshaft, which means it constantly consumes some of the engine's power, even when the car is moving in a straight line and no power is required. The main elements of the system are a fluid reservoir, a high-pressure pump, a distributor and a hydraulic cylinder.
The key advantage of power steering is its ability to absorb impacts transmitted from the wheels to the steering wheel when hitting uneven roads. Hydraulic system Provides excellent feedback and smooth operation, which is highly appreciated by drivers of large cars and SUVs. In addition, the design of such amplifiers is quite simple and repairable: most components can be restored or replaced separately without changing the entire assembly. The fluid in the system not only performs a transmitting function, but also lubricates the rubbing pairs, extending the life of the mechanism.
However, hydraulics also have significant disadvantages. Constant operation of the pump increases fuel consumption, albeit slightly, but over long-term operation this is noticeable. The driver also needs to regularly monitor the level and condition of hydraulic fluid, since its leakage can lead to rapid failure of the pump and loss of control. In winter, thickening fluid may temporarily increase steering effort until the engine is fully warmed up.
Always use only the brand of power steering fluid recommended by the vehicle manufacturer. Mixing different types of oils (for example, ATF and specialized hydraulic oils) can lead to swelling of the rubber seals and system failure.
It is important to remember the temperature conditions of hydraulics. When the steering wheel is held in the extreme position for a long time (for example, when parking), the pressure in the system reaches a maximum, which can lead to overheating of the fluid and damage to the seals. Therefore, it is not recommended to keep the steering wheel turned all the way for more than 5-7 seconds.
Electrohydraulic booster (EGUR)
An intermediate link in the evolution between classical hydraulics and full electrification was electrohydraulic power steering (EGUR). Visually and structurally, it is very similar to a conventional power steering: it also uses fluid, a pump and a hydraulic cylinder. The main difference is the pump drive. Instead of being mechanically connected to the engine via a belt, the pump is driven by a separate electric motor. This allows the system to operate independently of the crankshaft speed of the internal combustion engine.
The main goal of introducing electric power steering was to improve fuel efficiency. Since the electric pump is turned on only when the steering wheel is turned, the constant load on the engine, characteristic of classic power steering, disappears. Electrohydraulic mechanism retains all the advantages of hydraulics: good information content of the steering wheel and the ability to dampen vibrations from the road surface. Such systems can often be found on cars of the Volkswagen Group, Ford and some Peugeot models of previous generations.
Despite the improved efficiency, the power steering retained the main disadvantage of hydraulic systems - the presence of fluid, hoses and seals, which over time can lose their tightness. In addition, the addition of the electrical part (pump with motor and control unit) complicates the diagnosis. If in a conventional power steering there is practically nothing to break, then in an electric power steering there may be problems both mechanical and electrical in nature.
Why is electric power steering installed on electric cars?
On electric vehicles, using an electrically driven pump (EGUR) instead of a mechanical pump from an internal combustion engine was a logical step, since there is simply no internal combustion engine. However, now manufacturers are increasingly switching to a pure electric power steering (EP) even in electric cars, in order to eliminate fluid and hydraulics completely.
Maintenance of electrohydraulics requires attention to the condition of the electrical contacts of the pump. Oxidation of connectors or moisture ingress into the wiring can cause system failure, even if the mechanical part is fully operational. When replacing fluid in such systems, a pumping and adaptation procedure is often required through a diagnostic scanner.
Electric power steering (EPS)
The most modern and common type today is electric power steering (EUR). This system is completely free of hydraulics: there is no fluid, pumps, hoses or cylinders. The force is created by an electric motor that acts directly on the steering shaft or rack. The operation of the motor is controlled by an electronic control unit (ECU), which reads data from the steering angle sensor, vehicle speed sensor and torque sensor.
The advantages of the electric power steering are obvious: high energy efficiency, since electricity is consumed only at the moment of turning, no need for regular maintenance (changing fluid, belts), and compactness. Electric drive allows you to easily implement complex functions such as automatic parking, lane keeping and variable steering ratio (Active Steering) depending on speed. At low speeds the steering becomes very light, and on the highway it becomes heavy and stable.
However, EUR also has its critics. Many drivers complain about the lack of information content and “artificial” sensations compared to hydraulics. The electric motor cannot completely smooth out small vibrations from the road, so some of the shock is transferred to the driver’s hands. In addition, electronic control unit sensitive to overheating during intensive operation (for example, frequent parking maneuvers), after which the system may temporarily limit the force or turn off.
ESD is the future of the automotive industry, providing maximum efficiency and integration with autopilot systems, but losing to hydraulics in tactile feedback and service life under extreme loads.
EUR repair often involves replacing the assembly or an expensive overhaul with reprogramming. If an electric motor winding burns out or a torsion sensor fails, simply replacing parts can rarely be done. Accurate zero position calibration and testing of all electrical circuits is required.
Comparison of amplifier types: characteristics table
To finally understand what kind of power steering there are and how they differ in operation, it is convenient to summarize their main parameters in a single table. This will help you quickly evaluate the pros and cons of each system when choosing a car or diagnosing problems.
| Characteristics | Power Steering (Hydraulics) | EGUR (Electrohydraulics) | EUR (Electric amplifier) |
|---|---|---|---|
| Energy source | Engine (belt) | Car electrical system | Car electrical system |
| Fuel consumption | Higher (constant load) | Medium (works as needed) | Minimum |
| Service | Replacing fluid, belt | Fluid replacement, electrical inspection | Not required |
| Information content | High | High | Medium/Low |
| Reliability | High (mechanical) | Medium (hybrid) | Depends on electronics |
Analyzing the table, we can conclude that the choice of system often depends on the class of the car. For heavy SUVs and trucks, hydraulics or electro-hydraulics remain preferred due to their ability to withstand heavy loads. For compact city cars and the budget segment, it becomes the uncontested leader electric amplifier.
It is also worth noting that modern electric power steering systems are becoming more and more advanced. Engineers are implementing algorithms that simulate hydraulic behavior and improving gearbox designs to reduce backlash and improve durability. Therefore, the gap in sensations between types of systems is gradually closing.
Typical faults and diagnostics
No matter what type of amplifier is installed in your car, the system is subject to wear and tear. Understanding the symptoms of a malfunction will help you avoid an emergency on the road. For hydraulic systems, the most common problem is fluid leakage from the pump seals or rack. The first sign is a drop in the level in the tank and the appearance of oil spots under the car.
In electric amplifiers, the torque sensors or the electric motor itself most often fail. Symptoms may include jerking of the steering wheel, spontaneous steering, or the illumination of a malfunction lamp on the dashboard. Diagnostics of EUR is impossible without connecting a scanner that reads error codes from the control unit’s memory.
- 🚗 Humming when turning - a classic sign of problems with the power steering pump or low fluid level.
- ⚡ The steering wheel light came on - indicates an error in the power steering system; adaptation or replacement of the sensor may be required.
- 💧 Oily stains on the steering rack elements - a signal about the need to replace the seals or repair kit.
Particular attention should be paid to extraneous sounds. A knock in the steering rack may indicate wear and tear in the mechanical part, which is typical for all types of amplifiers. If the knocking sound is accompanied by heavy rotation of the steering wheel, the problem may lie in a jammed distributor spool (in the power steering) or a malfunction of the worm gear (in the power steering).
⚠️ Attention: Operating a vehicle with a faulty power steering is dangerous! If the system fails, the force on the steering wheel increases significantly, which can lead to loss of control, especially at low speeds or when maneuvering. When the first symptoms appear, contact service immediately.
Maintenance and service life extension
In order for the steering system to serve for a long time, you must follow simple operating rules. For owners of cars with power steering and electric steering, it is critical to monitor the quality and level of the fluid. It is recommended to replace it every 60-80 thousand kilometers, even if the manufacturer claims “fluid for the entire service life”. The old fluid loses its properties, becomes saturated with moisture and metal shavings, killing the pump from the inside.
EUR owners should protect the system from overheating. Do not keep the steering wheel turned to the extreme position for a long time. It is also important to monitor the condition of the electrical connectors under the hood: they should be dry and tightly closed. Contact corrosion is a common cause of glitches in an electronic amplifier.
☑️ Steering check-up
Regularly checking the integrity of the steering rack protective boots is another important point. The entry of dirt and water into the mechanism due to a torn boot leads to accelerated wear of the rubbing pairs and corrosion of the rod. Replacing the boot is inexpensive, but saves you from expensive repairs to the entire rack.
Frequently asked questions (FAQ)
Is it possible to convert power steering to electric power steering?
This is theoretically possible, but in practice it is extremely difficult and expensive. You will need to replace the steering rack, install an electric motor, control unit, wiring and integration with the vehicle's CAN bus. Often the cost of such modifications exceeds the cost of the car itself. It is easier and more reliable to repair the standard system.
Why is it hard to turn the steering wheel when it's cold?
In systems with power steering, this may be due to thickening of the fluid in the cold. In the ESD, a heavy steering wheel when cold may indicate a malfunction of the temperature sensor or the motor itself, which does not reach operating mode. If after warming up the problem disappears, this is normal operation of the viscosity properties of the liquid.
What is the service life of electric power steering?
The resource of the EUR directly depends on the operating conditions. In the urban cycle with frequent turns and parking, the electric motor can run 150-200 thousand km. On the highway, where the steering wheel is rarely turned, the system lasts almost the entire life of the car. The main enemy is overheating and vibration.
Is it necessary to warm up the power steering in winter?
Yes, it is desirable. After starting the engine in severe frost, let the car idle for 1-2 minutes so that the fluid in the reservoir warms up a little and becomes less viscous. Sharp turns of the steering wheel on thickened liquid can damage the pump seals.