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How Power Steering Works

How Power Steering Works

The electric steering is an independent electric motor system, which is designed to assist the driver, reducing the effort and providing greater comfort for the drivers and more precision in the maneuvers.

The electric steering is an independent electric motor system, which is designed to assist the driver, reducing the effort and providing greater comfort for the drivers and more precision in the maneuvers.

A car with electric steering can have a fuel economy of up to 5%, this because it does not consume the direct power of the engine and is not connected directly to it by the belt.

How Power Steering Works

More modern vehicles are already equipped with electric steering, which has sensors that inform the speed of the vehicle and the rotation applied by the driver at the wheel to a control center (ECU).

The electric steering was launched in 99 and in the early years, the electric assistance system already represented 4% of sales, compared to 30% in 2011. The projection is that cars with this type of direction surpass 50% in 2015, much on account of legislation to reduce greenhouse gas emissions worldwide. It was for Italy that the use of the new system began in practice, in 2001, an innovation that landed in Brazil in 2003 with Fiat Stilo.

By Nexteer’s calculations, approximately 5 billion liters of fuel were saved by cars equipped with this type of steering. As a result, it began to equip even larger vehicles, such as the Ford F-150 pickup in the United States.


How Electric Steering Works

The operation of the electric steering is independent of the engine and dispenses all belts that make the oil pump work, common in cars with power steering.

The driver applies a torque to the steering wheel in the direction of turn it and a special optical sensor stores the purpose of the driver in making a curve, the angular speed of rotation of the steering wheel angle, the direction of rotation and communicates with the electronic central of the system.

How Power Steering Works

The system searches internally for its operating temperature since the support torque will vary with its temperature. The system will work 100% efficiency while the working temperature is below 60 ° C, with 75% at 80 ° C. The maximum operating temperature of the plant is 85 ° C.

All the operation of the electric motor is controlled by the control module called MC which, because it is not coupled to the motor, has a functional independence and operates in several different modes selected automatically by the module.

When the vehicle is moving in a straight line, the system operates in “standby” mode or in standby mode. The control module identifies that no hydraulic assistance is required and the electric motor operates at a nominal speed of 2333 revolutions per minute, which reduces power consumption.

With a continuous movement of the steering wheel, the electronic system registers a certain resistance to the steer ship and promptly sends a signal to the electric motor raising the rotation levels from 2333 to about 3300 per minute. At this point, the equipment controls the maximum assistance mode, causing the hydraulic pressure and flow necessary for the balanced operation of the system, giving a more precise and immediate aid to the driver.

If maximum temperature and current levels are reached, the MC activates the survival mode and continuously reduces the hydraulic power available to the driver to the limit of the standby mode.

If it reaches 130ºC temperature or a battery voltage greater than 16 volts or the electric current reaches 75 amperes for more than one second, the module begins to operate manually, completely stopping the hydraulic assistance, all to protect the electrical system.

If the battery voltage drops to 9 volts or the alternator signal drops for more than 0.1 seconds, the MC also completely resets the hydraulic system assist in a decreasing ramp mode of approximately 26 seconds.
In operation of this system does not compromise the drivability of the vehicle, but the driver will have to apply a greater force on the steering wheel to continue travel.


Torque sensor

This sensor is a very simplified start-up optical device. Basically, it is an LED that emits a light signal that will be picked up by the detector between the two reference disks with a series of standardized holes.

The first disc rotates integrally with the input shaft derived from the steering wheel and the second rotates integrally with the output shaft.

The movement of the discs creates a series of pulses by the suspension or not of the light sent to the detector. These pulses of light are altered by the detector in a series of electrical pulses. The number of pulses is directly proportional to the angle of rotation and the frequency of the pulses at the angular velocity of the axis.

A second transceiver assembly is inserted into the system in order to identify the direction of rotation of the steering wheel and check the plausibility of the previous sensor signal – angle and speed.

The steering effort and the intention of the driver to make a maneuver are created from the angular deflection of the torsion bar that connects the input shaft (steering wheel) to the output shaft (steering column).

The “zero” reference is defined in programming via specific diagnostic equipment (scanner).


Hydraulic steering

The main objective of this steering is to facilitate the driving of the vehicle, allowing the driver a reduction in the force applied on the steering wheel, which starts to command the mechanical part with greater ease, since the greater work is done hydraulically.

This reduction makes the driver save about 80% of the energy he would use to drive the car. In this way, driving the car becomes something safer in critical situations, such as tire overflow, sharp gradients in the runway and detour of obstacles, and enable more precise maneuvers.

The main problems that the steering system can present are:

  • Leakage
  • Damaged seal
  • Constant acute wheezing
  • Noise in the pump
  • Fluid level below specified
  • Steering wheel return with difficulty
  • Worn or loose bus items
  • Loose steering mechanism
  • Steering column without lubrication
  • Offset wheels
  • Heavy Steering
  • Suspension terminals and pivots worn or damaged Steering column interference
  • Loose system belt
  • Hydraulic Hose Obstruction
  • Internal leakage Air in hydraulic system
  • Directional Rotary Valve Damaged or Restricted
  • Hydraulic noise
  • Pressure hose outside specified
  • Fluid level
  • Connecting tubes
  • Pump relief valve or defective steering mechanism


How to Change Power Steering Fluid

The fluid used in the hydraulic steering is a type of lubricant whose characteristic is not consumable, so it should not lower its indicated level in the tank next to the engine.

If this happens it is because something is wrong with the direction of your car. So the best thing to do is take him to a workshop to make an inquiry.

The most recommended is to do an annual inspection and change it as soon as it completes more than 50 thousand kilometers. If you do not use your car extensively, the oil can be changed every 2 years.

To check that the oil is at normal levels in the tank, just take a closer look at the engine of the car. Normally, the tank has an external indication of the level.

The function of the hydraulic oil / hydraulic fluid is the transmission of force. It is also essential to lubricate the internal parts of the system, avoiding premature wear.

In order to obtain a good oil, it is necessary to be aware of certain requirements, such as resistance to water contamination, resistance to oxidation, a good performance against wear, good anti-foaming behavior, viscosity index IV: minimum 100, cannot attack the hydraulic system and have good anti-corrosion additive.
It is possible to find oils in the mineral type, treated and synthetic mineral. The first is the most common because the vast majority of hydraulic oils are made from mineral oils.

The treated mineral oils are mineral oils made by a special process of hydrocracking. The difference from this with the aforementioned is the high resistance to oxidation and aging.

Synthetics, in turn, are generally non-toxic and can be used in hydraulic systems that require low fluidity and high flash point. The service life of these lubricants reduces consumption and maintenance cost.


EHPS system

The system electro-hydraulic power steering (EHPS – Electric Hydraulic Power Steering) is a new and advanced design, which has been supplying conventional power steering system in order to make a minimum energy consumption of the vehicle and adjust it to better driving.

This innovation will bring some advantages over the conventional power steering system, and it may be noted that the high electrical and mechanical efficiency results in a low power consumption of the engine.
In addition, it has several modes of operation, with the standby mode, which enable the reduction of energy consumption; and every electro-hydraulic steering system is supplied by a single company, which makes the system more optimized with a high degree of reliability.

Also be reduce the duration of removal and installation of the component, since there are few interconnected components and the degree of difficulty of performing this operation is minimal. The latest advantage is the complete electronic management, which allows the use of protection strategies against high temperatures, pressure, voltage spikes and current.


The advantages of electric steering

Accuracy in the maneuvers and reduction of the physical effort, these are the main advantages that the driver can have with the use of the direction with electric assistance. Among the advantages is the reduction in car maintenance and the ease of extending the assistance to the manufacturer when desired, as can be seen in the Dual Drive system in the Fiat Stilo model. In this model, a button on the console activates the City function and makes the steering 50% lighter.

This type of steering offers, with the car, stopped greater lightness in the maneuvers, and more safety when the car reaches higher speeds.

Electric steering has better efficiency in the use of engine compartment space, offers less damage to the environment, greater design flexibility and greater fuel economy, all due to the reduction of engine power losses.

This design eliminates pumps and hoses and reduces manual working time in assembly. Through this information, the control unit determines the direction and the intensity of the assistance and controls an electric motor that acts on the steering column.

This motor has a torque that changes according to the need for the assistance calculated by the control panel. Control centers, also known as UCE, have self-diagnostics that confirm all functions, monitoring any problem.


Normal, hydraulic or electric steering?

In modern times, vehicle buyers look for items that offer greater comfort while driving, as well as looking for those that best suit their needs. To make a good choice, experts give some tips:

  • For beginner drivers, the most indicated direction is the normal one, because with it there is control both in fast maneuvers as in beacons;
  • When compared to hydraulics, electric steering significantly reduces the power consumption of the vehicle;
  • Some of the so-called electrical directions can be more or less “light” according to the speed of the car. This feature is called progressive.
  • If the price is a differential to be considered, normally the cheapest system order for the least account is a normal; the hydraulic and the electric.
  • The power steering is ideal for making beacon maneuvers, due to its quick response when starting the vehicle.
  • Regardless of type: normal, hydraulic or electric, the steering system has long since left the hall of luxury items. Now it is seen as a safety component, so keep an eye on maintenance to avoid accidents and headaches.