Have you ever wondered what makes your car respond effortlessly to your slightest touch on the steering wheel? It’s all thanks to the ingenious invention known as power steering. From nimble city driving to effortless highway cruising, power steering plays a pivotal role in enhancing your driving experience.
Power steering is a mechanical or hydraulic system designed to aid the driver in turning the wheels with minimal effort. It utilizes various components to reduce the physical exertion required to steer, allowing for precise control and smoother handling.
This technological advancement has revolutionized the automotive industry, making driving more comfortable, convenient, and accessible to a wider range of individuals. In this article we’ll explore how power steering works, different types of power steering systems available on the market, and how to troubleshoot a faulty power steering system.
What is Power Steering?
A power steering is a mechanical device equipped on a motor vehicle that helps drivers steer the vehicle by augmenting the steering effort needed to turn the steering wheel, making it easier for the vehicle to turn or maneuver at lower speeds.
Hydraulic or electric actuators add controlled energy to the steering mechanism, so the driver can provide less effort to turn the steered wheels when driving at typical speeds, and reduce considerably the physical effort necessary to turn the wheels when a vehicle is stopped or moving slowly.
Power steering can also be engineered to provide some artificial feedback of forces acting on the steered wheels.
Hydraulic power steering systems for cars augment steering effort via an actuator, a hydraulic cylinder that is part of a servo system. These systems have a direct mechanical connection between the steering wheel and the linkage that steers the wheels.
This means that power-steering system failure (to augment effort) still permits the vehicle to be steered using manual effort alone.
Electric power steering systems use electric motors to provide assistance instead of hydraulic systems. As with hydraulic types, power to the actuator (motor, in this case) is controlled by the rest of the power steering system.
Other power steering systems have no direct mechanical connection to the steering linkage; they require electrical power. Systems of this kind, with no mechanical connection, are sometimes called “drive by wire” or “steer by wire”, by analogy with aviation’s “fly-by-wire”.
In this context, “wire” refers to electrical cables that carry power and data, not thin wire rope mechanical control cables.
Manual Steering vs. Power Steering Systems
In manual steering systems, the driver relies solely on mechanical force to turn the wheels. This type of steering can be physically demanding, especially in larger or heavier vehicles. Mechanical steering racks work fine when the vehicle is moving at any kind of speed.
However, once the vehicle is static, turning the wheels in place becomes a tug of war with the steering wheel.
This is where power steering systems come into play. They utilize various mechanisms to amplify the driver’s steering input, resulting in smoother and more manageable steering.
History
The first power-steering system fitted to a production car debuted in the 1951 Chrysler Imperial, and the competition quickly followed suit.
Not only did power steering do the obvious allow the driver to steer a heavy vehicle with much less effort and greater comfort but it also allowed engineers to improve steering response, which is how quickly the car changes direction when the driver turns the wheel.
Before power assist became available, cars’ steering systems had been geared so that it took many turns of the wheel to negotiate tight turns or to park.
This slow gearing gave drivers more leverage against the high effort required to steer the front wheels. But the advent of power steering allowed engineers to quicken the steering ratio.
How much the steering wheel has to be turned relative to how much the angle of the front wheels changes because the additional steering effort could now be offset by the new system. In fact, it was more than just offset; steering a car became nearly effortless.
Hydraulic and Electric Power Steering Systems
There are two primary types of power steering systems: hydraulic power steering (HPS) and electric power steering (EPS).
Hydraulic Power Steering System
Hydraulic power steering systems have been widely used in vehicles for several decades. These systems rely on hydraulic pressure generated by a power steering pump to assist the driver’s steering effort.
The power steering pump is driven by the engine and pressurizes hydraulic fluid, which is then transmitted to the steering gear or rack and pinion assembly. The hydraulic pressure assists in turning the wheels, making steering easier for the driver.
Components of a Hydraulic Power Steering System
A hydraulic power steering system comprises several key components:
- Power Steering Pump – The power steering pump is typically driven by the vehicle’s engine via a belt. Its primary function is to pressurize the power steering fluid, creating the necessary hydraulic force to assist with steering. The pump draws fluid from the reservoir and circulates it through the system.
- Power Steering Fluid and Reservoir – Power steering fluid serves as the hydraulic medium within the system. It provides lubrication, cooling, and hydraulic pressure for smooth steering operation. The power steering fluid reservoir stores an adequate supply of fluid and allows for fluid expansion and contraction.
- Steering Gear or Rack and Pinion – The steering gear, also known as the rack and pinion assembly, converts the rotational motion of the steering wheel into lateral movement, turning the vehicle’s wheels. It contains a gear mechanism and a rack that engages with the steering linkage, allowing for precise control over the direction of the wheels.
- Power Steering Hoses and Hydraulic Lines – Power steering hoses and hydraulic lines transport pressurized fluid between the power steering pump, steering gear, and other relevant components. These hoses and lines are designed to withstand high-pressure conditions and ensure the proper flow of fluid throughout the system.
Functioning of a Hydraulic Power Steering System
When the driver turns the steering wheel, a series of events occur within a hydraulic power steering system:
- Steering Wheel Input – The driver applies force to the steering wheel, initiating a rotational movement.
- Power Steering Pump Activation – As the driver turns the steering wheel, a valve mechanism within the steering gear detects the movement and signals the power steering pump to activate.
- Fluid Pressure Generation – The power steering pump pressurizes the power steering fluid and sends it through the hoses or hydraulic lines to the steering gear.
- Steering Assistance – The pressurized fluid enters the steering gear, exerting force on the rack and pinion mechanism. This force assists in moving the wheels according to the driver’s steering input, reducing the effort required.
- Return of Fluid – After assisting with steering, the fluid returns to the power steering pump and gets recirculated through the system. The power steering pump continues to provide assistance as long as the steering wheel is being turned.
Electric Power Steering System
Electric power steering systems have gained popularity in recent years due to their efficiency and versatility. Instead of hydraulic pressure, these systems employ an electric motor to assist the driver’s steering inputs.
The electric power steering motor is connected to the steering column and can adjust the steering assistance based on various factors such as vehicle speed and driving conditions.
Electric power steering systems are generally lighter, more fuel-efficient, and offer greater flexibility in terms of customization and integration with other vehicle systems.
Components of an Electric Power Steering System
An electric power steering system consists of several key components:
- Electric Power Steering Motor – The electric power steering motor is the heart of the system. It is typically located on the steering column or the steering rack. The motor generates torque based on the driver’s steering input and provides the necessary assistance for turning the wheels.
- Power Steering Controller – The power steering controller, often integrated into the vehicle’s electronic control unit (ECU), acts as the brain of the EPS system. It receives inputs from various sensors and the steering column torque sensor to determine the required level of assistance from the electric power steering motor.
- Steering Column Torque Sensor – The steering column torque sensor detects the amount of torque or rotational force applied to the steering column by the driver. This information is sent to the power steering controller, which adjusts the assistance provided by the electric power steering motor accordingly.
- Vehicle Speed Sensor – The vehicle speed sensor measures the speed of the vehicle. It provides input to the power steering controller to modulate the level of assistance based on the driving conditions. Higher assistance may be provided at lower speeds for easy maneuverability, while lower assistance may be given at higher speeds for better road feel.
Benefits of Electric Power Steering
Electric power steering systems offer several advantages over hydraulic power steering systems, including:
- Improved Fuel Efficiency – Electric power steering systems are more energy-efficient compared to hydraulic systems since the electric motor only consumes power when assistance is required. This efficiency leads to improved fuel economy and reduced emissions.
- Customization and Control – EPS systems provide greater flexibility in adjusting the steering feel and response. The power steering controller can be programmed to offer different levels of assistance, allowing for customization based on the vehicle’s characteristics or driver preferences.
- Integration with Vehicle Systems – Electric power steering systems can be seamlessly integrated with other vehicle systems, such as driver-assistance features and stability control systems. This integration allows for improved coordination and enhanced overall vehicle performance.
Different Types of Electric Power Steering Systems:
There are various types of electric power steering systems:
- Column-Assist Electric Power Steering – In this type of EPS system, the electric motor is mounted on the steering column, assisting the driver’s steering efforts directly.
- Rack-Assist Electric Power Steering – In a rack-assist EPS system, the electric motor is integrated into the steering rack assembly. This design provides a more direct and precise steering response.
- Pinion-Assist Electric Power Steering – Pinion-assist EPS systems feature the electric motor located on the steering gear pinion. This design offers a compact and lightweight solution.
Understanding the components and functioning of an electric power steering system provides insights into its advantages and various configurations.
In the subsequent sections, we will explore common causes of electric power steering failures, symptoms of issues, and essential maintenance practices for optimal performance.
Causes of Power Steering Failure
Power steering failures can occur in both hydraulic and electric power steering systems. Understanding the common causes of power steering failures is essential for diagnosing and addressing issues promptly. Let’s explore some of the primary reasons why power steering systems can fail.
Lack of Power Steering Fluid
In hydraulic power steering systems, a common cause of failure is a low or inadequate level of power steering fluid. Insufficient fluid can result from leaks, improper maintenance, or a worn-out power steering pump.
When the fluid level is low, the system may not generate enough hydraulic pressure to provide the necessary assistance, leading to stiff or difficult steering.
Worn-out or Damaged Power Steering Belts and Pulleys
In hydraulic power steering systems, power is transferred from the engine to the power steering pump via a belt. Over time, these belts can become worn, loose, or damaged, affecting the pump’s performance.
Similarly, damaged or misaligned power steering pump pulleys can lead to belt slippage, reducing the power steering pump’s efficiency and causing steering issues.
Issues with the Power Steering Pump or Motor
Both hydraulic and electric power steering systems can experience problems with their respective pumps or motors. In hydraulic systems, a failing power steering pump may struggle to generate adequate pressure, resulting in diminished steering assistance.
Electric power steering motors can encounter electrical or mechanical faults, leading to a complete loss of steering assistance or intermittent operation.
Leaking Power Steering Hoses and Seals
Power steering systems utilize hoses and seals to transport pressurized fluid. Over time, these components can develop leaks due to wear, aging, or damage.
Leaking hoses or seals result in a loss of power steering fluid, which reduces the system’s hydraulic pressure and affects steering performance.
Faulty Sensors or Control Modules
In electric power steering systems, issues can arise from faulty sensors or control modules.
Malfunctioning sensors, such as the steering column torque sensor or vehicle speed sensor, may provide inaccurate information to the power steering controller, leading to improper steering assistance.
Additionally, problems with the power steering controller itself can disrupt the system’s functionality.
Symptoms of Power Steering Failure
Recognizing the symptoms of power steering failure is vital for addressing issues promptly and preventing further damage to the system. Here are some common indicators that suggest problems with the power steering system:
Difficulty in Turning the Steering Wheel
One of the primary signs of power steering failure is an increased effort required to turn the steering wheel.
You may experience stiffness or resistance when attempting to steer the vehicle, particularly at lower speeds or during parking maneuvers. This can make it challenging to maneuver the vehicle effectively.
Unusual Noises When Steering
Power steering problems can produce abnormal noises. If you hear a squealing, whining, or groaning sound when turning the steering wheel, it may indicate a worn-out or failing power steering pump or belt.
Additionally, air trapped in the power steering system can cause a bubbling or gurgling noise.
Vibration or Jerking Sensations While Driving
A malfunctioning power steering system can cause vibrations or jerking sensations in the steering wheel while driving.
These vibrations may be accompanied by an inconsistent or unpredictable steering feel, making it challenging to maintain a steady course.
Warning Lights Related to Power Steering
Some vehicles are equipped with warning lights specifically designed to indicate power steering issues.
If you see a power steering warning light illuminated on your dashboard, it is essential to have the system inspected as soon as possible.
Gradual Loss of Power Steering Assistance
In certain cases, power steering failure may occur gradually rather than abruptly. You may notice a progressive decrease in the amount of steering assistance provided by the system. This loss of assistance can make steering increasingly difficult and should be addressed as soon as possible.
It’s important to note that these symptoms can also be indicative of other underlying problems with the steering or suspension systems. If you experience any of these signs, it is advisable to consult a qualified mechanic or service professional for a comprehensive diagnosis and appropriate repairs.
In the next section, we will discuss troubleshooting techniques and steps to identify and resolve power steering issues effectively.
Troubleshooting Power Steering Issues
When faced with power steering problems, it’s essential to follow a systematic troubleshooting approach to identify and resolve the underlying issues. Here are some steps you can take to troubleshoot power steering problems:
- Step 1: Check Power Steering Fluid Levels – Begin by checking the power steering fluid reservoir. Ensure that the fluid level is within the recommended range. If the fluid level is low, it may indicate a leak or other issues within the system. Top up the fluid if necessary, but also be mindful of addressing any underlying leaks.
- Step 2: Inspect Power Steering Belts, Pulleys, and Hoses – Examine the condition of the power steering belts, pulleys, and hoses. Look for signs of wear, damage, or looseness. Tighten or replace loose or worn-out belts, and repair or replace damaged hoses or pulleys as needed. Ensure proper alignment and tension of the belts.
- Step 3: Assess Power Steering Pump or Motor Functionality – For hydraulic power steering systems, listen for unusual noises coming from the power steering pump when the engine is running. If the pump is excessively noisy or fails to provide adequate assistance, it may need to be repaired or replaced. In electric power steering systems, check for proper operation of the electric power steering motor and control modules.
- Step 4: Look for Leaks – Inspect the power steering system for any visible leaks. Check the power steering hoses, seals, and connections for signs of fluid leakage. Address any leaks by repairing or replacing the affected components.
It’s important to remember that power steering systems can be complex, and attempting extensive repairs without the necessary knowledge and expertise may cause further damage. When in doubt or when faced with challenging issues, it is advisable to seek the assistance of a qualified mechanic or automotive service professional.
Advantages of Power Steering
Following are the advantages of power steering:
- It prevents the wheel from transferring the loading to the steering column.
- Power steering reduces driver fatigue.
- It lowers the input torque and continuous steering function.
- In power steering, the oil output is directly proportional to steer speed.
Disadvantages of Power Steering
Following are the disadvantages of power steering
- The design of the power steering is complicated.
- Power steering is costly than the manual steering
- It has a fluid leakage problem.