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Submitted To:Submitted To: Engr.Hafiz Khuram AliEngr.Hafiz Khuram Ali

Submitted By:Submitted By: M. Faheem Asif 07-MCT-22M. Faheem Asif 07-MCT-22

Sultan Fateh Ali Khan 07-MCT-27Sultan Fateh Ali Khan 07-MCT-27

AHSAN ULLAH SHAH 07-MCT37AHSAN ULLAH SHAH 07-MCT37

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How Power How Power Steering worksSteering works

Topic of Presentation:Topic of Presentation:

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Objective:Objective:

Study of Mechatronics viewing Power Study of Mechatronics viewing Power Steering.Steering.

What is Mechatronics and its role in What is Mechatronics and its role in Power Steering.Power Steering.

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Overview Overview

Mechatronics is actually overlapping of Mechatronics is actually overlapping of Mechanical,Electronic and Control Mechanical,Electronic and Control (Computer) systems(Computer) systems

Control MechanicalElectrical

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What is Power Steering?What is Power Steering?

You know that when you turn the steering wheel in You know that when you turn the steering wheel in your car, the wheels turn. Cause and effect, right? But your car, the wheels turn. Cause and effect, right? But a lot of interesting stuff goes on between the steering a lot of interesting stuff goes on between the steering wheel and the tires to make this happenwheel and the tires to make this happen

We'll see how the most common types of car steering We'll see how the most common types of car steering systems work. Then we'll examine power steering and systems work. Then we'll examine power steering and find out about some interesting future developments in find out about some interesting future developments in steering systems steering systems

Power steeringPower steering is a system for reducing the steering is a system for reducing the steering effort on cars by using an external power source to effort on cars by using an external power source to assist in turning the wheels. assist in turning the wheels.

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History of Power SteeringHistory of Power Steering

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Types of Power Steering:Types of Power Steering:

There are many types of Power Steering likeThere are many types of Power Steering like Hydraulic Power Steering.Hydraulic Power Steering. Electrohydraulic Power Steering.Electrohydraulic Power Steering. Electric Power steering.Electric Power steering.

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Hydraulic Power SteeringHydraulic Power Steering

Hydraulic Power Steering systems work by using a belt driven pump to provide hydraulic pressure to the system

This hydraulic pressure is generated by rotary pump which is driven by engine

As the Engine speed increases the pressure in hydraulic fluid also increases

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Hydraulic Power SteeringHydraulic Power Steering

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Working – Hydraulic Power Working – Hydraulic Power SteeringSteering There are following key components in hydraulic power steering Rotary-Vane Pump The hydraulic power for the steering is provided by a Rotary-Vane

Pump (see diagram below). This pump is driven by the car's engine via a belt and pulley. It contains a set of retractable vanes that spin inside an oval chamber.

Rotary-Vane Pump

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Working – Hydraulic Power Working – Hydraulic Power SteeringSteering As the vanes spin, they pull hydraulic fluid from the return line at low

pressure and force it into the outlet at high pressure. The amount of flow provided by the pump depends on the car's engine speed. The pump must be designed to provide adequate flow when the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is running at faster speeds

Rotary-Vane Pump

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Working – Hydraulic Power Working – Hydraulic Power SteeringSteering The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at high engine speeds when so much fluid is being pumped.

Rotary-Vane Pump

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Working – Hydraulic Power Working – Hydraulic Power SteeringSteering Rotary-Valve A power-steering system should assist the driver only when he is exerting force on the steering wheel (such as when starting a turn). When the driver is not exerting force (such as when driving in a straight line), the system shouldn't provide any assist. The device that senses the force on the steering wheel is called the rotary valve.

Rotary-Valve

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Working – Hydraulic Power Working – Hydraulic Power SteeringSteering The key to the rotary valve is a torsion bar. The torsion bar is a thin rod

of metal that twists when torque is applied to it. The top of the bar is connected to the steering wheel, and the bottom of the bar is

connected to the pinion or worm gear (which turns the wheels), so the amount of torque in the torsion bar is equal to the amount of torque the driver is using to turn the wheels. The more torque the driver uses to turn the wheels, the more the bar twists

Rotary-Valve

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Advantages – Hydraulic Power Advantages – Hydraulic Power SteeringSteering

Hydraulic power system (HPS) has no steering wheel torque as compared to mechanical system

In HPS no freezing of steering systems is caused by dried up grease and corrosion in the steering tube of the motor

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Disadvantages – Hydraulic Power Disadvantages – Hydraulic Power SteeringSteering

Hydraulic Power Steering systems are less efficienct in following areas as compared to most modern Electric Power steering

systems:- Engine efficiency Space efficiency Environmental compatibility

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Electro-hydraulic systems Electro-hydraulic systems ::

Electro-hydraulic power steering Electro-hydraulic power steering systems, sometimes abbreviated EHPS, systems, sometimes abbreviated EHPS, and also sometimes called "hybrid" and also sometimes called "hybrid" systems, use the same hydraulic assist systems, use the same hydraulic assist technology as standard systems, but the technology as standard systems, but the hydraulic pressure is provided by a pump hydraulic pressure is provided by a pump driven by an electric motor instead of driven by an electric motor instead of being belt-driven by the engine. being belt-driven by the engine.

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Electric systems:Electric systems:

Electric Power Steering systems use Electric Power Steering systems use electric components with no hydraulic electric components with no hydraulic systems at all. Sensors detect the motion systems at all. Sensors detect the motion and torque of the steering column and a and torque of the steering column and a computer module applies assistive power computer module applies assistive power via an electric motor coupled directly to via an electric motor coupled directly to either the steering gear or steering either the steering gear or steering column.column.

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EPS or Electronic Power EPS or Electronic Power SteeringSteering

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MicroprocessorMicroprocessor MotorMotor

SensorsSensors

Output TorqueOutput Torque

Steering Torque

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Electric Power Steering Electric Power Steering EPS in Honda NSXEPS in Honda NSX

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The NSX SystemThe NSX System

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Construction of NSXConstruction of NSX

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Basic WorkingBasic Working

The NSX system consists of a rack-and-The NSX system consists of a rack-and-pinion steering gear with an electric motor pinion steering gear with an electric motor installed concentrically around the rack installed concentrically around the rack

Transmission of Motor power through a Transmission of Motor power through a recirculating ball drive mechanism recirculating ball drive mechanism

Steering sensors are located on the input Steering sensors are located on the input shaft and consist of:shaft and consist of:

Torque sensor & rotation sensor Torque sensor & rotation sensor

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An "interface" circuit digitise the signals An "interface" circuit digitise the signals from the torque sensor and rotation from the torque sensor and rotation sensor into signals the control electronics sensor into signals the control electronics can process.can process.

Inputs from the “steering sensor” & Inputs from the “steering sensor” & “vehicle's speed sensor” are sent to “vehicle's speed sensor” are sent to microprocessor control unit. The sensor microprocessor control unit. The sensor inputs are then compared to determine inputs are then compared to determine power required according to a power required according to a preprogrammed "force map". The control preprogrammed "force map". The control unit then sends out the appropriate unit then sends out the appropriate command to the "power unit" which then command to the "power unit" which then supplies the electric motor with current.supplies the electric motor with current.

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The Microprocessor Control The Microprocessor Control UnitUnit

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Operating modes of EPS: Operating modes of EPS:

““Normal Mode" Normal Mode" ““Return Mode“Return Mode“ “ “Damper Mode" Damper Mode"

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Basic Features:Basic Features:

(1) It's compact and light and (2) it's not (1) It's compact and light and (2) it's not parasitic (robbing power from the engine) parasitic (robbing power from the engine) since it only draws electric power on since it only draws electric power on demand. But it also provides precise demand. But it also provides precise control and is easy to vary the amount of control and is easy to vary the amount of assistance with an electric unit. Plus it's assistance with an electric unit. Plus it's simpler to install (especially in a mid- or simpler to install (especially in a mid- or rear-engined car), there are no hydraulic rear-engined car), there are no hydraulic lines to break, and it's quieter lines to break, and it's quieter

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Advantages:Advantages:

Constant Feed-back Constant Feed-back Less Consumption of powerLess Consumption of power Different operating modesDifferent operating modes Self-diagnosing faults by monitoring the Self-diagnosing faults by monitoring the

system's inputs and outputs system's inputs and outputs

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DisadvantagesDisadvantages

One of the disadvantage of EPS is that it One of the disadvantage of EPS is that it cannot be used in big vehicles.cannot be used in big vehicles.

It reduces the feel of steering.It reduces the feel of steering. Electronic components failure can occur.Electronic components failure can occur.

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Thanks a lotThanks a lot