CRUISE CONTROL AND ADAPTIVE CRUISE CONTROL EXPLAINED !!

In 1945 a blind yet prolific inventor, Mr. Ralph Teetor invented a system which is now one of the most important features of any good car globally, the Cruise Control. The system was first introduced in 1958 with Chrysler models such as Imperial, New Yorker and Windsor and by 1960 all Cadillacs were offered with Cruise Control.

Presently most of the global automobile giants like Volvo, Mercedes-Benz, BMW, Audi, Nissan, Kia, Honda, Nissan, etc. offer this feature with most of their cars.

What Is Cruise Control?

Cruise Control is a system which is capable of maintaining the speed of a car at a desired level. The conventional or I would say the basic systems are capable of taking over the throttle once the driver activates Cruise Control and sets the desired speed. In most of the cars, the cruise control buttons are mounted on the steering wheel, just like the audio control buttons, whereas in older car models a separate lever is provided similar to the ones used for windscreen wipers and headlights.

Once enabled the new ones only ask the driver to set the maximum and minimum cruising speeds after which it takes over the controls and the same gets disabled as soon as the driver presses the throttle, brake or clutch pedal.This feature is very useful for long drives where the roads are fairly good and high speed cruising is possible. The driver can set the car’s cruise control system close to the speed limit of the road and just relax with his foot off from the accelerator and brakes, the car will maintain the speed set on the cruise control system using the arrangements (car’s computers, activators etc.) which are provided in the car.

What Is Adaptive Cruise Control Systems? How Is It Different?

Adaptive Cruise Control or ACC is an advanced type of cruise control system and is the most widely used one. The system is capable of adjusting the speed of the vehicle depending on various factors influencing it. In simple language, if your car’s cruise control is set to a speed of 80 KMPH and the car in front of you is going slower than 80 KMPH, your car will slow down automatically to maintain a safe distance from car in front of you. Once the car in front goes 80 KMPH or faster or gets out of the way, the cruise control system again speeds up to initially set 80 KMPH without any manual intervention ! Isn’t it useful for a long highway journey.

Behind the grille of a vehicle, radars or lasers are installed that track the distance and speed of the vehicle ahead. This information is sent to the main ECU or the computer and together they help the car to reduce speed or re-accelerate depending on the position and speed of the car in front. This way, Adaptive cruise control is a more refined version of the cruise control system and is a very nice feature for even the city driving conditions with slow moving traffic.

MEANING OF GRADE WRITTEN ON BOLT HEAD EXPLAINED !!

A fastener is a device that mechanically joint two or more objects together. In general, fasteners are used to create non-permanent joints. That is, joints that can be removed or dismantled without damaging the joining components.

Before starting we need to clear some basic mechanical engineering concept.

Proof Load:  It is defined as the maximum tensile force that can be applied to a bolt that will not result in plastic deformation. In other words, the material must remain in its elastic region when loaded up to its proof load.

Yield Strength: Maximum load at which a material exhibits a specific permanent deformation or plastic deformation.

Tensile Strength: Tensile strength is a measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. The tensile strength of a material is the maximum amount of tensile stress that it can take before failure.

In simple words “ digit written on bolt head is indicate its grade”

 Now let’s explore all thing in deeply.

What Does a Grade Mean?

The grade of your industrial fasteners not only determines how much stress they are able to stand, but also why type of tool must be used to tighten them. For a grade 8.8, you must use the part turn method of tightening with a torque wrench; this is where the fold is fit snug tight with your fingers and then advanced up to three turns, depending on length and size. Indicating washers may also be used in the part turn method, and added security of the joint can be accomplished by using other fasteners and fixings, such as spring washers, wired heads, nuts, and split pins. 

What’s the difference between 10.9 and 8.8 bolts?

The first digit relates to the ultimate strength of the material, while the second is the ratio of yield stress to ultimate strength. Thus grade 10.9 bolts have an ultimate material tensile strength of 1000N/mm2 and the yield (or proof) stress is 90% of the ultimate strength. Similarly grade 8.8 bolts have an ultimate strength of 800 N/mm2 and a ratio of yield/proof stress to ultimate strength of 80%. 

DIFFERENCE BETWEEN HOT SPARK PLUG AND COLD SPARK PLUG EXPLAINED !!

Introduction:

In order to ignite air fuel mixture we need heat.In case of diesel engines (compression ignition engines) this head is achieved by the compression of gases.But in case of spark ignition engines we need to have an external source to ignite air fuel mixture because compression is not enough to ignite the mixture.

A spark plug is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark, while containing combustion pressure within the engine.

There are two types of spark plug :

• Hot Spark Plug
• Cold Spark Plug

“Cold” spark plugs normally have a short heat flow path. This results in a very quick rate of heat transfer. Additionally, the short insulator nose found on cold spark plugs has a small surface area, which does not allow for a massive amount of heat absorption.

On the other hand, “hot” spark plugs feature a longer insulator nose as well as a longer heat transfer path. This results in a much slower rate of heat transfer to the surrounding cylinder head.

The heat range of the spark plug must be carefully selected in order to create an optimal thermal performance. If the heat range is not correct, you can expect serious trouble. Typically, the appropriate firing end temperature is  900-1,450 degrees. Below 900 degrees, carbon fouling is possible. Above it, overheating becomes an issue.