10 mech seminars

By FaaDoOEngineers.com 1- Four wheel steering system

Four-wheel steering, 4WS, also called rear-wheel steering or all-wheel steering, provides a

means to actively steer the rear wheels during turning maneuvers. It should not be confused

with four-wheel drive in which all four wheels of a vehicle are powered. It improves handling

and helps the vehicle make tighter turns. Production-built cars tend to understeer or, in few

instances, oversteer. If a car could automatically compensate for an understeer /oversteer

problem, the driver would enjoy nearly neutral steering under varying conditions. 4WS is a

serious effort on the part of automotive design engineers to provide near-neutral

steering. The front wheels do most of the steering. Rear wheel turning is generally limited to

half during an opposite direction turn. When both the front and rear wheels steer toward the

same direction, they are said to be in-phase and this produces a kind of sideways movement

of the car at low speeds. When the front and rear wheels are steered in opposite direction, this

is called anti-phase, counter-phase or opposite-phase and it produces a sharper, tighter turn.

ADVANTAGES OF 4WS

1. The vehicle‟s cornering behavior becomes more stable and controllable at high speeds

as well as on wet or slippery road surfaces.

2. The vehicle‟s response to steering input becomes quicker and more precise

throughout the vehicle‟s entire speed range.

3. The vehicle‟s straight-line stability at high speeds is improved. Negative effects of

road irregularities and crosswinds on the vehicle‟s stability are minimized.

By FaaDoOEngineers.com 4. Stability in lane changing at high speeds is improved. The vehicle is less likely to go

into a spin even in situations in which the driver must make a sudden and relatively

large change of direction.

5. By steering the rear wheels in the direction opposite the front wheels at low speeds,

the vehicle‟s turning circle is greatly reduced. Therefore, vehicle maneuvering on

narrow roads and during parking becomes easier.

By FaaDoOEngineers.com 2- Catalytic converter for cars

Millions of cars or the road means only one thing, an excellent source for air pollution. The

amount of pollution that all cars produce together can create big problems. The amount of

pollution that all cars produce together can cause big problems. Government created laws that

restrict the amount of pollution that cars produce to solve it. Auto makers have made many

improvements to car engines and fuel systems to keep up with these laws. In 1975, an

interesting device called catalytic converter was created. The device, converts harmful

pollutants into less harmful emissions before they ever leave the car‟s exhaust system.

The exhaust from the combustion in a car engine is comprised of six main ingredients:

1. Nitrogen gas, Carbon dioxide and water vapor are the three of the main emissions.

These gases do not cause damage to the atmosphere.

2. Carbon Monoxide, other hydrocarbons and Nitrogen Oxides result in a majority of the

pollution caused by cars.

Carbon monoxide is a colorless and odorless gas that can kill you if too much is

inhaled

Hydrocarbons are produced during incomplete combustion and these hydrocarbons

can be broken down by the sun, creating ground level Ozone, also known as smog.

Nitrogen Oxides can cause acid rains.

Catalytic convertors are designed to reduce these last three emissions.

Construction:

The core is often a ceramic/stainless steel foil honeycomb.

- Increases the amount of surface area

- Support the catalyst. Also called “catalyst support”.

By FaaDoOEngineers.com

A wash coat is used to make converters more efficient because a mixture of silica and

alumina will form a rough and irregular surface which leads to more surface area. Therefore,

more places for active precious metal sites. The catalyst is added to the wash coat before

applied to the core.

Platinum is the most active catalyst and is widely used. Other materials such as palladium and

rhodium have also been used.

By FaaDoOEngineers.com 3-Hybrid vehicles

The dictionary defines hybrid as something of mixed origin. A hybrid vehicle is one that

combines a smaller than normal internal combustion gasoline engine with an electric motor.

An engine that combines two or more sources of power is called a hybrid engine.

Typical features in a hybrid include the following:

• Produces much less power than an average

• Produces much less pollution than standard gasoline cars

• Usually constructed of ultra light weight materials like carbon fiber or aluminum to

overcome the power gap.

• Generally designed to be more aerodynamic than most cars, allowing them to “slice”

through the air instead of pushing it out of the way

• A process called regenerative braking is employed to store the kinetic energy generated by

brake use in the batteries, which in turn will power the electric motor.

Power usage:

• Electric power is used at starts and stops, low speeds (generally below 25 km/hr)

• Gasoline engine comes to play at cruising or highway speeds

There are two types of gasoline-electric hybrids:

• Parallel hybrid:

Gasoline engine and electric motor work together to move the car forward

• Series hybrid

Gasoline engine either directly powers an electric motor that powers the vehicle, or changes

batteries.

Hybrids achieve improved efficiencies using several approaches:

• Employ regenerative braking to recover energy and downsize or right size the engine or

primary power source.

• Control the engine or primary power source to operate more efficiently and/or work more

often in a more efficient range.

By FaaDoOEngineers.com 4- Electronic fuel injection (EFI)

Electronic Fuel Injection (EFI) is a substitute for the conventional metering system which

mixes the air and fuel in the correct ratio before feeding it down to the main cylinder to

power the vehicle.

Usually in a bike a carburetor is responsible for carrying out this task. But, the downside of

using a carburetor is that it has fixed settings and it has certain limitations. To overcome this

negative aspect of a new system has been introduced. However, for this brand new system to

work, it needs data from several sensors. These sensors include an engine speed sensor,

temperature sensor, voltage sensor, throttle position sensor, oxygen sensor and an air flow

sensor. The data collected from the various sensors are send to the Electronic control unit

(ECU). The ECU makes use of the data provided from the sensors to determine the spark

advance, the length of spark and other parameters. Then the exact air fuel mixture for that

particular instant is fed into the cylinder which in turn delivers optimum power and clean

exhaust. All this process is done continuously and happens many times in every second.

A cross section of a fuel injector is shown below:

Typical EFI components:

1) Injectors

2) Electronic control module (ECU)

3) Fuel pressure regulator

4) Fuel pump

5) Wiring harness

6) Sensors

Advantage:

1) Although the electronic fuel injection is much more complicated than a carburetor, it

is much more efficient.

By FaaDoOEngineers.com 2) Fault finding is easy with the right tools

Disadvantage:

1) Higher cost than carburetor.

By FaaDoOEngineers.com 5-Water powered vehicle

Not a Gimmick! Finally the science of Hydrogen automotive power has been made a reality!

Technically a device that converts the energy stored in hydrogen into motion can be called a

Hydrogen engine. Hydrogen would make a great fuel for the environment since burning

Hydrogen produces nothing but water!

Hydrogen Powered vehicle essentially consists of the following

1) Fuel tank

Liquid hydrogen is stored in a tank at the rear of the car and is pumped forward to the fuel

cell stack as and when required.

2) Fuel Cell Stack

When Hydrogen is combined with Oxygen in a fuel cell a chemical reaction creates

electricity.

1) Battery Pack

The battery pack is periodically recharged by the fuel cell. The power from the battery pack

is used to provide rapid acceleration.

2) Electric Motor

The stack provides electricity for the electric motor that powers the vehicle

Right from the year 1625, when Johann Baptista van Helmont discovered the gas, Hydrogen;

people were curious enough to find the uses of the new found gas. It nearly took a mind

boggling 181 years to develop an internal combustion engine which runs on a mixture of

hydrogen and water by the icon of 18th

century who is none other than, Francois Issac de

Rivaz. The Swiss inventor, is credited with the development and construction of the world‟s

By FaaDoOEngineers.com first IC engine back in 1806. From then onwards, it was always a challenge to develop the

best IC engine. This has lead to developing different varieties of engines.

A pictorial representation of the Hydrogen powered vehicle is shown below.

By FaaDoOEngineers.com 6- Remote controlled material handling equipment

Prior to the introduction of the so called “Material handling equipment” humans had to

perform physical labor to carry out heavy duty tasks. This could be made possible by

employing a huge number of workers. However, when the goods came in bulk unloading and

loading turned out to be a very time consuming affair. The use of Material handling

equipment in logistics has played a significant role in making the loading and unloading

activities easier and faster.

Ask yourself the question “Why are „Remote controlled’ material handling equipment

used?” and almost instantly you arrive at the logical answer that the chief benefit would be

allowing personal to control their machine from a safe distance.

Remote control can be achieved by two different modes:

1) Radio frequency (RF) Signals

RF signals are further divided into two categories.

a) Narrow-band system b) Spread spectrum system.

2) Infrared light

Infrared method works by transmitting a beam of light

Infrared mode of radio control is preferred over RF signals because of the safety and

precision that it offers. Since the infrared method works by transmitting a beam of light, once

the beam is out of sight, the beam is obstructed and the controls turn off. That is, the operator

must always be in view of the RCMHE, which in turns aids safety as the full visibility of the

operator over the machine is critical. Precise, in the sense that with the use of RF technology

there is always a chance of interference with other signals and might lead to accidents,

Infrared remote control makes this type of mistake impossible.

Applications:

1) Transfer of components from one container to another especially fragile objects

2) Transfer of hazardous/explosive objects

3) Operation in high temperature environment

Although it is advantages to use RCMHE, proper training for the staff handling the RCMHE

is a prerequisite to ensure safe working.

By FaaDoOEngineers.com 7- Fire fighting robot

A robot system for fire fighting in tunnels

Different kinds of accidents are possible in a tunnel but, accidents involving fire are the most

dangerous of all. If it is not possible to extinguish the fire in minutes, it would be so hot that

human life will be at risk. But, one of the biggest fears among emergency personnel who

should respond to tunnel fires is the possibility of finding hazardous material fueling fire!

That was exactly what happened on the 13th

of May,1949 which resulted in the Holland

tunnel fire. When something as grave as that happens, there is threat to life not only because

of the rampaging fire but also because of the toxic materials. In such a situation it is best to

leave the job to robots! A device that can detect and extinguish fire on its own.

Protection of life and reduction of property loss is what everyone has in mind when it comes

to fire fighting. But, how does one achieve this in practice? To make this possible we should

first ask ourselves 2 simple questions:

Question 1) What are the factors affecting tunnel fire size and spread?

Question 2) What is the best tunnel fire suppression system?

Answers, to those questions would give you an idea of how to tackle the fire effectively.

Reference:

1) The Handbook of Tunnel Fire Safety by Alan Beard and Richard Carvel

2) International Tunnel Fire-Safety Design Practices

By FaaDoOEngineers.com 8- Over speed indicator and Accident Avoidance systems in a four

wheeler

Except for the Autobahn in Germany, almost all roads have specific speed limits. And it is

difficult for the driver to always look out for speed limits signs and adjust his speed

accordingly. Over speed indicator is a device that tells the driver if he is exceeding the

particular speed limit. With the over speed indicator in your car you can be sure that you are

not going get yourself booked for over speeding. The system has a computer which stores the

speed limits of different areas. The GPS in the system feeds the exact location of the car to

the computer which looks up in its database to determine the permissible speed for the area

and limits the car within the allowable speed.

Accident Avoidance systems in a four wheeler is a cocktail of several technological marvels.

1. Emergency Brake Assist (EBA)

In an emergency, many people do not depress the brake pedal hard enough. EBA senses an

emergency braking situation and helps the driver to reduce speed in the shortest distance

possible.

2. Dynamic Stability and traction Control (DSTC)

DSTC makes driving on twisty and slippery road conditions safer, by using sensors to detect

whether any of the wheels is losing traction. DSTC has the ability to cut power in a flash,

helping the car to regain its grip. If in any case the car shows a tendency to skid the system

automatically slows the particular wheels to help maintain control.

By FaaDoOEngineers.com

3. Electronic Brake Distribution (EBD)

EBD makes sure that the braking forces of the car are distributed between the front and the

rear brakes in order to optimize braking efficiency.

4. Anti-Lock braking system (ABS)

With ABS you can brake as hard as you can and steer yourself to safety without the fear of

wheels locking up and skidding.

By FaaDoOEngineers.com 5. Blind Spot information system (BSIS)

Using cameras set just below the outer rear view mirrors the BSDS tell you if there is any

vehicle in your blind spot.

6. Night Vision

Driving during the night becomes safe than ever with the night vision where one can see

clearly on the control display even in pitch black. Thanks to infra red technology.

By FaaDoOEngineers.com 9- Wall climbing robot

You would rather hesitate to do the inspection and maintenance in a typically dangerous

environment like the exterior of a tall building or a nuclear facility and pray to God to

provide for someone else to do the same. Well, consider your prayers answered! A wall

climbing Robot is willing to go through the trouble so that you can still keep smiling!

But, the idea of developing a wall climbing robot is always held back by the mighty force of

GRAVITY!

And BEWARE. This won‟t be an Easy Project for you. But this definitely is a fantastic

Mechanical Engineering Seminar Topic, especially if you can demonstrate how it defies

gravity.

You need to move against gravity to accomplish the task. Adhesion is what is required

primarily, to help keep the robot firmly on to the wall. Reliable adhesion is a major factor in

developing a WCR. Once a proper suction is obtained, locomotion is the next step. It is also

equally important to keep the weight as low as possible so that the effort to stick on to the

wall is quite low.

Adhesion is achieved by making use of

1. Suction cups

Suction cups offer excellent grip (almost upto 1 atm). But, the negative aspect of using a

suction cup is that it needs a vacuum pump. Since the vacuum pump is bulky and has high

By FaaDoOEngineers.com power consumption it is rather difficult to accommodate one in a WCR. Moreover, a suction

cup would find itself useless when trying to stick to a rough surface.

2. Electrostatic chuck (ESC)

ESC achieves controlled adhesion by means of electrostatic forces.

Mobility is achieved by making use of an electric motor.

With these things in mind, I hope you would have got an insight of the Wall Climbing Robot.

Ref: http://spectrum.ieee.org/robotics/robotics-software/wallclimbing-robot-spies

By FaaDoOEngineers.com 10- Adaptive cruise control system

There is no denying the convenience of cruise control. Conventional cruise control systems

however, are not always practical when it comes to driving in moderate traffic. Whenever the

vehicle in front of you is moving slower than you are, you need to depress the brakes and de-

activate the system. When traffic clears you need to press the accelerator, return to the

desired speed and reset the cruise control.

Not very convenient, huh?

Imagine a cruise control system that not only controls your speed, to match the cars ahead of

you but also controls the braking as well. Car companies like Daimler Chrysler, BMW,

Jaguar, Nissan, Toyota, Honda, Volvo and Ford have found the technology!

Using advanced Radar technology, Adaptive cruise control automatically scans the driving

environment for slower vehicles ahead and can slower the vehicle to adapt, to current traffic

conditions. Once traffic clears, the system will automatically return to the cruise set speed.

Another advantage of this radar system is it actually helps you brake more smoothly in an

emergency. Assume the car upfront suddenly stops. Most people apply the brake too lightly

at first and when they realize they are not going to stop, they suddenly slam them on! Well,

that is where the radar can fix things. It knows exactly how far the car in front of you and also

how fast you are travelling. So, it calculates how hard the brakes need be applied. If you are

not pushing hard enough, it automatically takes over.

Setting the adaptive cruise control is just like setting the conventional cruise control system.

First, while driving, press the “ON” control on the steering wheel. Accelerate to the desired

speed, press and release the “SET +” control on the steering wheel and take your foot off the

accelerator pedal. You can increase (“+” button) or decrease (“-“ button) the speed by using

the buttons on the steering wheel. Pressing the brake pedal deactivates the system.

Put it in cruise control and when it is a situation to slow down, the car does that

automatically! You don‟t have to put your foot on the brake at all. The system does it by

itself. And with a flick of the button and with no foot on the pedals the car speeds up by itself

to the pre-set speed

The key difference between Conventional cruise control and Adaptive Cruise control is being

able to adjust the Gap distance. When a vehicle ahead of you enters your lane or a slower

vehicle is on the same lane, vehicle speed will adjust automatically to maintain a pre-set gap

distance.

One thing to remember, is that you, the driver are always in control of the system and it is

your responsibility to ensure the safe operation of your vehicle.

Reference: http://sunnyday.mit.edu/safety-

club/workshop5/Adaptive_Cruise_Control_Sys_Overview.pdf

By FaaDoOEngineers.com