KNOW WHY DEPRESSION IS PROVIDED ON PISTON HEAD !!

At the end of compression stroke the piston is at the top dead center.During 
compression and power stroke both valves are closed.But in exhaust stroke exhaust valve is opened and piston moves from Bottom Dead Center to Top Dead Center.Similarly,in suction stroke intake valve is opened and piston moves from Top Dead Center to Bottom Dead Center.
To maintain high compression ratio, very less space is left on the top of the piston when it is on the top dead centre. 

So when valves open they can actually hit the piston if depression is not there. That cut in picture is called valve relief pocket that prevents valve from hitting piston.

INTAKE VALVE BIGGER,EXHAUST VALVE SMALLER !! KNOW THE REASON !!

In internal combustion engines, intake valve is used to introduce fresh charge to the cylinder and exhaust valve is used to expel burnt gases from cylinder.

Generally,intake valve is bigger than exhaust valve.The reason is explained below :

1.)The intake valve is bigger in size so that sufficient amount of charge can enter into cylinder as pressure outside is low.

2.)As the pressure after power stroke is high enough to push exhaust gases outside.So in the case of exhaust valve small opening is given.

3.)Being smaller also assists exhaust valves with keeping them cool which is important as exhaust valves often give rise to thermal problems.  

DIFFERENCE BETWEEN GRINDING AND POLISHING EXPLAINED !!

Grinding is an abrasive cutting action to meet dimensional accuracy and at same time smoother surface.Grinding removes saw marks and levels and cleans the specimen surface.Grinding uses fixed abrasives—the abrasive particles are bonded to the paper or platen—for fast stock removal.

The main purpose of the grinding step is to remove damage from cutting and to remove material approaching the area of interest.

Polishing is an super finishing operation which uses very fine abrasive just to improve roughness .Polishing removes the artifacts of grinding but very little stock.Polishing uses free abrasives on a cloth; that is, the abrasive particles are suspended in a lubricant and can roll or slide across the cloth and specimen.

The main purpose of polishing is to prepare specimen for microstructural analysis. It is the step which is required to completely eliminate previous damage.

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%. 

AERODYNAMICS AND ITS IMPORTANCE : EXPLAINED IN SIMPLE TERMS !!

Ever wondered why a Sportsbike can carry insane speeds than any of the other bikes you have seen/known? Is it because of the extra Horse Power that they carry? That actually might be one of the reasons that enables them to carry their speeds, for the rest there is an uncommon term in motorcycles known as Aerodynamics.

So, what is Aerodynamics? In simple terms Aerodynamics is a branch of dynamics concerned with studying the motion of Air, when interacting with a solid object. So, what is Automotive Aerodynamics? It is nothing but the study of the aerodynamics of road borne vehicles.

Why are Sportsbikes getting faster than the speed that they’ve established already a few years back in spite of added Horsepower and weight reduction? The reason is simply because of Aerodynamics. Sportsbikes manufacturers find serious difficulty in overcoming the tremendous drag forces generated by a bike that can touch insane speeds.

Why is that so?

The drag created by a solid object, which is a Motorcycle in this case, passing through the air is related to the square of its speed. So, as speed doubles, the drag would increase four folds. Since power is an end product of force and speed, the power requirement increases as the cube of the speed.

An Example

As an understanding example, let us consider an 8 HP scooter which could reach 50 kmph as it’s top speed. If you need to double it’s top speed to 100 kmph, the power it should carry should be 64 HP – Eight times it’s original power.

How is it the MotoGP bikes are getting there faster? The answer lies in their design they carry.

The Race Fairing design, the reduction in weight using Carbon Fibre parts, absence of rear view mirrors, blinkers and licence plates etc. It should also be kept in mind that, over high speed runs, the amount of extra power required to overcome the drag and to make it even faster increases by a huge amount.

What is Drag and how can it be reduced?

Drag is nothing but the wind resistance that slows you down. The first and foremost thing to know is that the aerodynamic drag isn’t just one type to overcome. There are other types of drag that keeps working on a Motorcycle besides the simpler Wind Resistance. The force used to distort working tyres into two flat contact patches creates a much bigger problem of rolling resistance, typically slowing you down. The more the tires deform from its actual shape, the greater the drag created, which is why it is very difficult to roll a Motorbike that has flat tyres than a normal bike with inflated tyres.

The amount of drag an object is subjected to comes from two things; the frontal area of the Motorbike and what’s called its drag co-efficient. There is also a mathematical figure that represents the aerodynamic efficiency of the object. In simple words, an extremely well streamlined object such as a Missile will have a much lower drag co-efficient than a blocky object like a truck or a Van (for example Maruti Omni). To sum this up, if one needs to increase the top speed of their Motorcycle, they need to carry out either of the two things; Make it smaller in size or reduce its drag co-efficient.

Improving Drag Co-Efficient

Improving drag co-efficient is all about keeping airflow smooth over an object. A teardrop design which is currently followed by majority of the Motorcycle manufacturers is a highly recommended shape because of its smooth, rounded front with a gradually reducing tail. In this design, the air is simply pushed out of its way as the teardrop moves. There are no low-pressure areas or turbulent vertices swirling behind which suck the object back and increase drag.

Aerodynamics in Bikes?

As with their advantages in mind making automotive objects faster, they have huge disadvantages when it comes to Motorbikes. The completely exposed nature of the design they carry is one. The biggest among all is the rider sitting high on the Motorbike creating a huge resistance. Keeping the airflow smooth around a rider and then re-attaching it behind the bike like a teardrop is the most difficult part.

With Spinning alloy wheels, the huge front forks and the massive flat radiator makes the flow of airflow a complete mess. To be also considered the rear alloy wheel, exhaust mufflers, swingarm and the back of the rider which makes for an irregular shaped teardrop tail.

It’s very hard to overcome such problems in conventional designs, that is why Motorcycle manufacturers go in for the Wind Tunnel testing of their Motorbike’s Aerodynamics to make their bikes much efficient and faster when it comes to reducing its drag levels. A few such examples are Honda’s CBR 1000RR and BMW’s S1000RR. In smaller Indian bikes it is the R15, R3 etc that have undergone the wind tunnel testing for the lowest drag co-efficient values, making them faster.

In these designs a large front fender sends the air out to the wide fairing sides, which smoothens the air over the rider’s legs and then back to their wide smooth tail sections that aim to re-attach the turbulent airflow at the rear side of the bike.

Drag

When it comes to talking about Top-Speed, the dominant type of drag is pressure drag. This Pressure drag is a force generated by the difference in pressure between the front and back of an object travelling at high speed. This can often be experienced by sticking out your hand in a moving car. The front of the hand creates a high pressure area and behind your hand is a low pressure area that gets created by the wind blowing on either side of your hand. The simple difference in the high and low pressure pushes your hand backwards and that’s how the drag force is created.

When it comes to production bike-based speed records, Suzuki Hayabusa is an all time favourite and then we have the more modern machines like the R1, S1000RR, ZX-14R etc.

The answer lies in their superior aerodynamic designs that make them easy to go fast.

Summing it up

As much as aerodynamics is important in a Motorbike design, letting aside the bike for now, the most important aerodynamic package to tune is your body. It is extremely important to work on the riding positions if someone needs to go extra fast than the rest. This can simply be achieved by tucking yourself behind the bubble screen that would gain you some more kmph on a critical situation in a race or a trackday.

If the rider is huge and well built, finding him tucked behind that small fairing is harder which explains why little shorter-built guys have an advantage in professional racing.

MARUTI BALENO MODIFIED TO LOOK LIKE MERCEDES A-CLASS AND SOLD !!

At first glance, it was a stylish Mercedes A-Class, and no one had any reason to doubt that the new red car racing through the roads of Northern Kerala was anything else.

But it turns out to be a Maruti Baleno, a wannabe Mercedes, which was heavily modified to look like the luxury car.

The Regional Transport Officer (RTO) of  Tirur in Malappuram District has confiscated the car in question which was illegally modified.

According to authorities the original owner of the car had modified it, replaced the bumper, with a Mercedes Diamond grille, alloy wheels, head and tail lamps and sporty air vents and logo to the point that even Mercedes dealers found it difficult to identify it as an imposture.

The RTO began the investigation after the state transport commissioner received a complaint.

But it took the authorities nearly two weeks to nab the imposture Merc which was hidden in the showroom of a second-hand car dealer.

According to authorities, the owner had put up the car for sale after he got into trouble with the law for the illegal modification.

Finally, with the help of police, the RTO managed to seize the Baleno and issued a show cause notice to the owner who is said to have spent up to Rs 3 lakhs to make the alterations in which was done in a local workshop.

Tirur RTO told a local TV channel that the car's registered owner who had purchased it had sold it to a friend without changing the registration. The friend who bought the car and modified it to look like Merc.

It was later sold to a third party who was using the Baleno at the time when it ran into trouble. It was a fight between the registered owner and the modified owner which alerted the authorities leading to the confiscation.

After the owner agreed to remove the modification, the authorities have decided not to deregister the car and let him off with a fine.

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TECHNICAL TERMS OF HEAT TRANSFER EXPLAINED !!!

1.)CONDENSATION – The change of state of a substance from the gaseous to the liquid form.

2.)CONDENSING – The process of giving up latent heat of vapourization in order to liquefy a vapour.

3.)CONDUCTION – Transfer of heat from one part of a material to another or to a material with which it is in contact.

4.)CONDUCTIVITY – The relative value of a material, as compared with a standard, in affording a passage through itself or over its surface for heat.

5.)CONSTANT VOLUME PROCESS– is one wherein a gas is heated (or cooled) in a fixed enclosed space (no change in volume occupied by the gas). There will be no workdone by the gas. The whole heat supplied will be stored in the form of internal energy.

6.)EQUIVALENT EVAPORATION – Amount of water in kg. that would be evaporated from water at 100°C into steam at 100°C and 1.03 kscm, by the heat put into steam actually evaporated in one hour by 1 kg of fuel.

7.)EXTRINSIC PROPERTIES– Also called extensive properties, are those properties which are dependent on the mass of the system. Examples are volume, weight and total energy.

8.)FACTOR OF EVAPORATION – A quantity which when multiplied by the amount of steam generated at a given pressure from water at a given temperature, gives the equivalent evaporation from and at 100°C.

9.)FREE EXPANSION– is a process wherein a fluid from a pressure chamber expands into a vacuum chamber through an orifice of large dimensions.

10.)FREE EXPANSION– is a process wherein a fluid from a pressure chamber expands into a vacuum chamber through an orifice of large dimensions.

REAR WHEELS IN TRACTOR ARE BIGGER THAN FRONT WHEELS !! WHY??

The word “tractor” is related to words like “traction” and “tractive,” from the Latin word “tractus” meaning drawing (pulling): a tractor is essentially a machine designed to pull things along, usually very slowly and surely.

Reasons for having big wheel at rear and small ones at front:

1.Grip or Traction

Farm tractors spend a lot of their life working in muddy, bumpy fields. If you’ve ever been in car that has driven over a muddy field, you will know that the car slips around on the surface of the mud, or it gets stuck. A large tyre on a tractor has much better grip pads that can ‘bite’ into the ground, as well as a large surface area that distributes weight more evenly which means the traction is a lot better. 

2.Steering

The two smaller wheels at the front have a much better steering radius which means it’s easier to turn sharp corners. This is really important to cover the maximum area of the field while carrying out different jobs like ploughing, sowing and harvesting. Being light weight and small is also really beneficial for ease of control.

3.Visibility

The large rear wheels of the tractor fix the driver’s seat at a higher elevation which ensures good visibility of the nose of the tractor and the corners of the field it ploughs.

4.Cost

Small tyres cost less than larger tyres, and therefore it is much cheaper to replace small tyres that the very expensive big ones! It’s worth noting that because the rear tyres have a much thicker tread that they don’t need to be replaced as often as the front ones.

5.Weight distribution

Having the driving axle higher above the ground means the tractor can pull more weight without the front of the tractor rising up. It works like a lever, where twice the height means twice the maximum pulling force before the tractor tips over.

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MONO SHOCK ABSORBER AND DUAL SHOCK ABSORBER : WHICH ONE IS GOOD ?

A motorcycle's suspension serves a dual purpose: contributing to the vehicle's handling and braking, and providing safety and comfort by keeping the vehicle's passengers comfortably isolated from road noise, bumps and vibrations.

The typical motorcycle has a pair of fork tubes for the front suspension, and a swingarm with one or two shock absorbers for the rear suspension.

The hydraulic shock absorbers used on the rear suspensions of motorcycles are essentially the same as those used in other vehicle applications.

There are two broad classification of suspension system :

a.)Dual shock absorber 
b.)Mono shock absorber

Dual shock refers to motorcycles that have two shock absorbers. Generally, this term is used to denote a particular era of motorcycles, and is most frequently used when describing off-road motorcycles.

On a motorcycle with a mono shock absorber rear suspension, a single shock absorber connects the rear swingarm to the motorcycle's frame. Typically this lone shock absorber is in front of the rear wheel, and uses a linkage to connect to the swing arm.

In this video a simplified comparison between both suspension is shown.Check it out :

5 AMAZING FACTS ABOUT TVS APACHE RR310 !!

TVS Motor has finally launched the Apache RR 310. It is the first motorcycle as part of TVS Motor's partnership with BMW Motorrad, co-developed alongside the BMW G310R. 

Number-5 The Apache RR 310 uses the same liquid-cooled, 313cc single-cylinder engine as the BMW G310R.

Number-4  Outputs are identical as of BMW G310R, at 34PS and 27.5Nm though one major difference is that TVS Motor is using its own custom ECU.

Number-3 The engine cylinder is inclined towards the rear of the motorcycle and has its intake towards the front and the exhaust towards the rear, as opposed to the other way round .

Number-2 The Apache RR 310 uses a 110/70 tyre at the front and a 150/60 tyre at the rear.

Number 1 -The Apache RR310 is also TVS Motor's first ever fully-faired sportsbike.

Interesting,Here is the full specifications of the bike:

DIFFERENCE BETWEEN REFRIGERATION AND AIR CONDITIONING EXPLAINED !!

Air conditioners and refrigerators are devices used to keep a space at a colder temperature than its surroundings. The main difference between refrigeration and air conditioning is that refrigeration, in general, refers to any process where thermal energy is taken away from a place and transferred to a place with a higher temperature. Air conditioning is a type of refrigeration where thermal energy is taken away from the air (typically in a room or a vehicle) in order to keep the air cooler. 

What is Refrigeration:

Refrigeration refers to processes that take thermal energy away from a place and gives off that energy to a place with a higher temperature. Naturally, thermal energy flows from a place with a higher temperature to a place with a lower temperature. Therefore, refrigeration runs against the natural heat flow and so it requires work to be done. Refrigerator is a name that we use for devices that are used to keep food at low temperatures. 

What is Air Conditioning:

Air conditioning is a type of refrigeration where thermal energy is taken away from the air in a large space such as a room or a vehicle. Air conditioners are fitted into rooms so that they cool the air inside them. Air conditioners also reduce humidity in rooms, because the water vapour in the room can condense around the colder parts of the air conditioner. The condensed water can be then drained off.

Difference Between Refrigeration and Air Conditioning:

Process

>Refrigeration is a process where thermal energy is transferred from a place with lower temperature to a place with  higher temperature using energy, against he natural flow of heat.

>Air conditioning is a type of refrigeration which is used to cool large volumes inhabited by people.

Functions

>Refrigeration is concerned only with regulating the temperature of a volume of air.

>Air conditioning is concerned with not only maintaining the temperature of a volume of air, but also maintaining he humidity and purity.

TOP 4 REASONS OF ENGINE SEIZE EXPLAINED !!

Engine seize is a condition when engine stops working due to some external or internal cause.In other words,engine seize is when some portion of the engine has lost lubrication and the moving parts have started to abrade each other, either from friction, heat or mechanical failure (example: broken piston ring) to the point that the engine stops turning.Unusual engine noises, low oil pressure, engine overheating, loss of power, misfiring, hard starting and similar driveability and performance complaints can all be indications of problems that need attention.

Causes of Engine Seize :

The major causes of engine failures can be lumped into four basic categories:

• Overheating (excessive heat)
• Lubrication (or the lack thereof)
• Detonation (Spark Knock )(Detonation)
• Misassembly

1.Overheating:

Overheating can be caused by any number of things. It is often the result of coolant loss or a low coolant level, which is turn may be due to leaks in hoses, the radiator or the engine itself. A weak radiator cap that leaks pressure can allow coolant to escape from the system. Not getting the cooling system completely filled after changing the antifreeze can allow steam pockets to form that make the engine overheat or run hot. An electric cooling fan that fails to come on due to a faulty thermostat, relay, wiring or motor may be an overlooked cause of overheating. So too can a slipping fan clutch. Even a missing fan shroud that reduces the fan's effectiveness may be a contributing factor.

Too much heat in an engine can cause serious problems because heat causes metal to expand. The hotter the engine gets, the tighter clearances become until there are no more clearances left. Overheating can cause valve stems to gall and stick, and pistons to scuff and seize. So if you see either of these conditions when you tear the engine down, it is a pretty good clue that overheating caused the engine to fail.

2.Lubrication:

Every engine needs oil between its moving parts not only to reduce friction but also to carry away heat. Oil is the primary means by which the rod and main bearings are cooled, as well as the pistons. So any reduction in oil flow may cause these parts to run hot, gall and seize.Overhead cam engines are even more vulnerable to oil starvation and low oil pressure problems than pushrod engines because the cam and valvetrain are farther from the pump. When an OHC engine is first started, it takes awhile for oil pressure to reach the cam bearings.

If you suspect engine damage may have been caused by a low oil level, check the dipstick to see how much oil is in the pan. A low oil level may be the result of neglect, oil leakage and/or oil burning.

3.Detonation:

Detonation (Spark Knock ) is a form of abnormal combustion that results from too much heat and pressure in the combustion chamber. The fuel ignites spontaneously causing a sudden rise in cylinder pressure. The result is a sharp hammer-like blow on the piston that produces a metallic knocking or pinging noise. Light detonation is considered normal and should not cause any damage, but heavy or prolonged detonation can crack rings, pound out piston ring grooves, punch holes through the tops of pistons, smash rod bearings and blow head gaskets.

Causes of detonation include excessive compression, elevated engine operating temperature, preignition, overadvanced ignition timing (spark knock), lean fuel mixture, spark plugs that have too hot a heat range for the application, low octane fuel, and even bad driving habits such as lugging the engine excessively with a manual transmission.

4. Misassembly:

You can probably ignore misassembly as a factor in a high mileage engine failure. But in a newly rebuilt engine or a low mileage failure, it should certainly be considered as a possibility. Some common mistakes to look for:

• Incorrect engine bearing clearances (too tight or too loose). Galling or seizure would tell you bearing clearances were too tight, while fatigue failure would point to excessive clearances.

• Insufficient Valve-to-Piston Clearance, or Piston-to-Cylinder clearance. Not checking clearances may result in valves hitting pistons (especially with high lift cams or rocker arms) or pistons sticking in cylinders.
• Misalignment. If the center main bearings show much greater wear than the end bearings, the crankshaft may be bent or the main bores may be misaligned. The underlying condition must be corrected by straightening or replacing the crank and/or align boring the block. The same applies to camshafts and cam bearings (pushrod & OHC).
• Failure to clean parts properly during engine assembly (not scrubbing out the cylinder bores with soap and water to remove debris and honing residue after they have been bored or honed, for example). Any junk that is left in the engine can scour bearings and wear surfaces.

STEEL WHEELS ARE USED IN TRUCKS AND BUSES RATHER THAN ALLOY WHEELS.WHY ???

Steel wheels are commonly used in trucks and buses rather than alloy wheels.Although alloy wheels are light in weight but steel wheels are preferred.This Video will give you a clear explanation of reason behind this.

KNOCKING : REASON AND SOLUTION EXPLAINED !!!

Knocking is a phenomenon of generating unwanted pressure wave which create unpleasant sound and can damage engine wall during combustion in engines. Knocking is largely associated with SI engines. It occurs due to self-ignition of unburned charge into combustion chamber.

When two flame fronts in SI engines collide, they produce an unwanted pressure wave which generates unpleasant sound (knock-knock) and can damage engine wall. Learn more about how Engine knocking works in this article.

Engine Knocking : 

Process:

Knocking is mainly associated with SI engines. It depends on auto ignition quality of fuel. The higher auto ignition temperature causes lower down knocking tendency. To understand whole concept of knocking let’s look out the combustion process.

When the piston reaches at TDC after compression, the spark plug produces spark which ignite the compressed mixture and starts the combustion process. It ignites only those part of mixture witch is in contact with spark plug and generates a main flame front which further ignites the whole mixture. This will generate a high temperature and pressure force inside the cylinder. This burnt part of mixture (combustion products) separate the fresh mixture from spark plug to the other end of the cylinder. As this flame front expands, it compressed the unburned part of the charge. This compression increases the temperature and pressure of unburned part of mixture. If the temperature of this part reaches its auto ignition temperature, it will ignite from other end and a new flame front starts moving towards opposite direction of main flame. When both of these flame fronts collide, it will generate a high pressure wave which produces an unpleasant sound and also damage the cylinder wall.

Factor affecting knocking:

Any factor which tends to decrease auto ignition temperature of charge or tends to ignite the charge except spark plug will affect knocking. Main affecting factor are given below.

Density factor:

The lower dense charge generates low energy and lower rise in temperature thus avoid knocking. If the density of charge decrease, will decreases the knocking tendency. The factors which affect the density of charge are as follows:

Compression Ratio

Increase in compression ratio will increase density of charge thus increase knocking tendency.

Mass of the charge induced:

The mass of charge depends on throttling or supercharging. A reduction in mass of induced charge, reduce the knocking tendency.

Time Factor:

The lower the time available to auto ignition will decrease the knocking tendency. The most affecting time factors are:

Engine Turbulence:

Turbulence reduces the ignition lag or time available for auto ignition. So increase in turbulence will increase the main flame speed and reduce ignition lag, thus reduces knocking tendency.

Spark Plug Location:

To reduce time available for auto ignition, spark plug should locate in order to have minimum flame travel for proper combustion. Generally spark plug located at center to reduce the tendency of knocking.

Engine Size:

As the engine size increase will increase the flame travel thus increases knocking tendency.

Combustion Chamber:

Combustion chamber design play main role in flame travel. The more compact the combustion chamber has minimum flame travel distance thus reduce knocking tendency. Also, the hot spot in combustion chamber should be avoided which can ignite the charge.

Temperature Factor:

Any factor which increases the temperature of inside gases will increase the knocking tendency. These are

Inlet Temperature of Mixture:

More the inlet temperature of mixture, increase tendency of auto ignition thus increase knocking tendency.  

Supercharging:

Supercharging increase both mass and temperature of inside the cylinder thus increases tendency of knocking.

Temperature of Combustion Wall

It will play main role in knocking. The higher the temperature of wall, more chance of auto ignition, thus more chance of knocking.

How to fix knocking:

We have known about knocking phenomenon and factor affecting it. The most methods are used to avoid knock are as follows.

• Spark plug location should select to minimize the flame travel distance.
• By proper cooling of Engine wall.
• Combustion chamber is so design which has less hot spot and higher turbulence.
• Uses higher auto ignition temperature fuels or add additive in gasoline to increase its knocking temperature.
• Higher engine speed will reduce knocking.
• Reduce compression ratio.
• Reduce supercharging to avoid knocking.