speedometer

The dashboard instrument cluster in your car organizes a variety of sensors and gauges, including the oil pressure gauge, coolant temperature gauge, fuel level gauge, tachometer and more. But the most prominent gauge -- and perhaps the most important, at least in terms of how many times you look at it while you're driving -- is the speedometer. The job of the speedometer is to indicate the speed of your car in miles per hour, kilometers per hour or both. Even in late-model cars, it's an analog device that uses a needle to point to a specific speed, which the driver reads as a number printed on a dial.

Photo courtesy of Dreamstime A modern speedometer

As with any emerging technology, the first speedometers were expensive and available only as options. It wasn't until 1910 that automobile manufacturers began to include the speedometer as standard equipment. One of the first speedometer suppliers was Otto Schulze Autometer (OSA), a legacy company of Siemens VDO Automotive AG, one of the leading developers of modern instrument clusters. The first OSA speedometer was built in 1923 and its basic design didn't change significantly for 60 years. In this article, we're going to look at the history of speedometers, how they work and what the future may hold for speedometer design.

Types of Speedometers

Photo courtesy of Siemens VDO Automotive The speedometer has gone through many changes in the last century.

There are two types of speedometers: electronic and mechanical. Because the electronic speedometer is actually a relatively new invention -- the first all-electronic speedometer didn't appear until 1993 -- this article will focus primarily on the mechanical speedometer, or the eddy-current speedometer.

Otto Schulze, an inventor from Strasbourg, filed the first patent for the eddy-current speedometer in 1902. Schulze conceived of the revolutionary device as a solution to a growing problem. Cars weren't only becoming more popular, they were also traveling faster. The average automobile's top speed just after the turn of the 20th century was 30 miles per hour, slow by today's standards but sizzling fast at a time when much of the world still moved at the leisurely pace of a horse-drawn carriage. As a result, serious accidents began to increase dramatically.

Schulze's invention allowed drivers to see exactly how fast they were traveling and to make adjustments accordingly. At the same time, many countries established speed limits and used police officers to enforce them. Early solutions required automobiles to have speedometers with two dials -- a small dial for the driver and a much larger dial mounted so police could read it from a distance.

How an Eddy-Current Speedometer Works

Photo courtesy of Dreamstime An eddy current speedometer

Let's say a car is traveling along the highway at a constant speed. That means its transmission and driveshaft are rotating at a speed that corresponds to the vehicle speed. It also means that the mandrel in the speedometer's drive cable -- because it's connected to the transmission via a set of gears -- is also rotating at the same speed. And, finally, the permanent magnet at the other end of the drive cable is rotating.

As the magnet spins, it sets up a rotating magnetic field, creating forces that act on the speedcup. These forces cause electrical current to flow in the cup in small rotating eddies, known as eddy currents. In some applications, eddy currents represent lost power and are therefore undesirable. But in the case of a speedometer, the eddy currents create a drag torque that does work on the speedcup. The cup and its attached needle turn in the same direction that the magnetic field is turning -- but only as far as the hairspring will allow it. The needle on the speedcup comes to a rest where the opposing force of the hairspring balances the force created by the revolving magnet.

What if the car increases or decreases its speed? If the car travels faster, the permanent magnet inside the speedcup will rotate faster, which creates a stronger magnetic field, larger eddy currents and a greater deflection of the speedometer needle. If the car slows down, the magnet inside the cup rotates more slowly, which reduces the strength of the magnetic field, resulting in smaller eddy currents and less deflection of the needle. When a car is stopped, the hairspring holds the needle at zero.

reference from howstuffworks.com.thanz for information

Oxygen Sensor

Every new car, and most cars produced after 1980, have an oxygen sensor. The sensor is part of the emissions control system and feeds data to the engine management computer. The goal of the sensor is to help the engine run as efficiently as possible and also to produce as few emissions as possible.

Rob Bouwman/Getty Images The amount of oxygen the engine can pull in depends on factors such as the altitude and the temperature of the air and engine.

A gasoline engine burns gasoline in the presence of oxygen (see How Car Engines Work for complete details). It turns out that there is a particular ratio of air and gasoline that is "perfect," and that ratio is 14.7:1 (different fuels have different perfect ratios -- the ratio depends on the amount of hydrogen and carbon found in a given amount of fuel). If there is less air than this perfect ratio, then there will be fuel left over after combustion. This is called a rich mixture. Rich mixtures are bad because the unburned fuel creates pollution. If there is more air than this perfect ratio, then there is excess oxygen. This is called a lean mixture. A lean mixture tends to produce more nitrogen-oxide pollutants, and, in some cases, it can cause poor performance and even engine damage.

The oxygen sensor is positioned in the exhaust pipe and can detect rich and lean mixtures. The mechanism in most sensors involves a chemical reaction that generates a voltage (see the patents below for details). The engine's computer looks at the voltage to determine if the mixture is rich or lean, and adjusts the amount of fuel entering the engine accordingly.

The reason why the engine needs the oxygen sensor is because the amount of oxygen that the engine can pull in depends on all sorts of things, such as the altitude, the temperature of the air, the temperature of the engine, the barometric pressure, the load on the engine, etc.

When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Your car performs poorly and uses more fuel than it needs to.

reference from howstuffworks.com

Tips Menjaga Keselamatan Tayar, memanjangkan j/hayat tayar anda

SELAIN enjin dan brek, tayar adalah antara komponen terpenting dalam sesebuah kenderaan. Kedegilan dan kecuaian menjaga dan menukar tayar yang tidak berbunga boleh mengundang masalah di jalan raya.

Tayar memainkan peranan penting ketika membrek dan mesti tahan lasak untuk menangani tekanan itu serta permukaan jalan yang ada kalanya tidak rata. Tayar juga mesti memberi keselesaan ketika mengambil selekoh dan kawalan stereng dalam apa juga keadaan.

Lazimnya, pengeluar tayar utama di negara ini sentiasa menyediakan tips keselamatan tayar kepada pemandu.

Berikut adalah antara beberapa panduan berguna:

# Segera tukar tayar jika bunganya sudah haus. Tayar begini mudah tergelincir, terjejas akibat kesan membrek dan kurang sensitif dari segi cengkaman. Dalam keadaan jalan basah, kenderaan mungkin terbabas dan menyukarkan kawalan pemandu.

# Pemilihan tayar memang penting untuk keselamatan, keselesaan, kawalan dan ekonomi.

Membrek dengan mengejut boleh menyebabkan tayar tergelincir. Periksa tekanan tayar sekurang-kurangnya dua kali sebulan, ketika tayar dalam keadaan sejuk. Pengeluar juga menekankan keutamaan mengekalkan tekanan tayar.

# Jangan memandu dalam keadaan tayar rosak. Tukar atau perbaikinya secepat mungkin.

# Segera baiki tayar tidak normal. Biasakan memeriksa tekanan, penjajaran dan pusingan tayar. Elakkan tabiat buruk ketika memandu seperti memandu terlalu laju, membrek secara mengejut dan mengambil selekoh secara berbahaya.

# Pastikan tayar gantian sentiasa dalam keadaan baik dan boleh digunakan serta memiliki tekanan angin mencukupi.

# Jangan gabungkan tayar dengan jejari dan tayar tanpa jejari. Pada kelajuan tinggi, keadaan itu menyebabkan gangguan kestabilan kenderaan yang mengakibatkan hilang kawalan serta kecederaan serius.

# Sentiasa pastikan skru tayar dipasang dengan betul dan tidak terlalu ketat. Mustahil dapat membuka skru tayar dengan pembuka tayar biasa sekiranya ia terlalu diketatkan dengan mesin pembuka tayar udara.

# Jangan biarkan tayar lebih muatan. Carta berat dan tekanan angin biasanya terpapar di tempat mengisi angin di mana-mana stesen minyak. Tayar hanya mampu menampung muatan maksimum jika ia memiliki tekanan angin maksimum.

# Jangan pasang tayar yang sudah digunakan sesuka hati melainkan anda tahu sejarahnya. Ia bermakna, anda bertuah sekiranya kakak anda menghadiahkan satu set tayar kerana beliau ingin membeli tayar baru.

What is natural gas

What is natural gas?
Natural gas is a mixture of hydrocarbons found in the ground independently or together with crude oil. Its composition varies (depending on where it is found), but its main component is "Methane"(CH4}. The rest of the gas is made up of varying amounts of other gases like ethane, propane, butane, and heavier hydrocarbons, plus Carbon Dioxide, Nitrogen, water and traces of other substances. Natural gas is a by-product of decaying vegetable matter in underground strata. Natural gas is the cleanest burning fossil fuel; it can help improve the quality of air and water,especially when used in highly polluted places.

Malaysia is blessed with abundant natural gas reserves. At 82.5 trillion cubic feet, these reserves are two times the amount of oil, thus there is opportunity to promote and diversify the use of the natural gas not just as a power source in the industrial and utilities sector; but also as an alternative fuel for vehicles. PETRONAS, through its wholly, owned subsidiary, PETRONAS NGV Sdn Bhd , have been making NGV available to Malaysian motorists through its expanding chain of NGV outlets in the Klang Valley and other major urban areas in the country.

FAQ's at bottom of this page. For more info on NGV visit: IANGV or Green Car Congress

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What is NGV ?
NGV stands for Natural Gas Vehicle. They operate similarly to traditional vehicles, but they use natural gas as fuel. Natural gas can power existing cars and trucks by converting the engines to a bi-fuel capability. To convert vehicles to natural gas requires installing a tank, fuel pressure regulators, and fuel lines. Most systems incorporate an electronic module which adjusts the engine to maintain comparable performance levels with either fuel. Limited production of dedicated natural gas engines and vehicles is under way at motor vehicle manufacturers. Refueling stations use the same natural gas as commercial facilities and residences. These stations now provide compressed natural gas for quick-fill.

FAQ's at bottom of this page

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How a Natural Gas Vehicle Work ?
1. Natural gas is compressed and enters the vehicle through the natural gas fill valve (receptacle).
2. It flows into high-pressure cylinders located in or under the vehicle.
3. In a bi-fuel NGV, a fuel selector on the dashboard permits selection of natural gas or gasoline to act as the fuel for the vehicle. A dedicated NGV operates solely on natural gas.
4. When natural gas is needed by the engine, it leaves the cylinders and passes through the master manual shut-off valve.
5. The gas goes through the high-pressure fuel line and enters the engine compartment.
6. Gas enters the regulator, which reduces pressure from up to 3,600 psi to near atmospheric pressure.
7. The natural gas solenoid valve allows natural gas to pass from the regulator into the gas mixer or natural gas fuel injectors. (Or, it shuts off the natural gas when the engine is not running or when, in the case of a bi-fuel vehicle, gasoline is selected).
8. In a bi-fuel NGV, natural gas mixed with air flows down through the gasoline carburetor or fuel injection system and enters the engine's combustion chambers. In a dedicated NGV, natural gas is injected into the engine's combustion chamber via specially designed natural gas fuel injectors.
9. In a bi-fuel NGV, when the driver selects gasoline, the conventional gasoline system is activated and the natural gas system is automatically shut off.

FAQ's at bottom of this page

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Why NGV?
Presented below is an outline of the benefits that CNG offers:

Green fuel - Commonly referred to as the green fuel because of its lead and sulphur free character, CNG reduces harmful emissions. Being non-corrosive, it enhances the longevity of spark plugs. Due to the absence of any lead or benzene content in CNG, the lead fouling of spark plugs, and lead or benzene pollution are eliminated.

Increased life of oils - Another practical advantage observed is the increased life of lubricating oils, as CNG does not contaminate and dilute the crankcase oil.

Mixes evenly in air - Being a gaseous fuel CNG mixes in the air easily and evenly.

Safety - CNG is less likely to auto-ignite on hot surfaces, since it has a high auto-ignition temperature (540 degrees entigrade) and a narrow range (5%-15%) of inflammability. It means that if CNG concentration in the air is below 5% or above 15%, it will not burn. This high ignition temperature and limited flammability range makes accidental ignition or combustion very unlikely.
Properties

Low operational cost - The operational cost of vehicles running on CNG, as compared to those running on other fuels, is significantly low.At the prevailing price of fuel ,operational cost of CNG vehicles is 68% lower than petrol and 36% lower than diesel.

FAQ's at bottom of this page

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Government Incentives & Legislations To Encourage Use of NGV

NGV is supported by the government of Malaysia with incentives and legislation to encourage vehicles owner to use NGV. NGV price is only 68 cent/litre equivalent of petrol, is cheaper than other fuels. NGV conversion kits are exempted from import duty and sales tax.
Reduction of road tax from existing levels:

* Monogas vehicle (NGV only) - 50% off
* Bi-fuel vehicle (Petrol & NGV) - 25% off
* Dual-fuel vehicle (Diesel & NGV) - 25% off

All these are major factors for potential owners to consider when making their vehicle fuel choices. However, what many owners may not be aware of is the safety record of NGV vehicles. NGV vehicles safety record compares favourably to other traditional fuels or alternative fuels available today. This is due to the superior (and still improving) technology, higher safety standards and the physical properties of NGV itself which makes it as safe or safer to use than petroleum-based fuels.

Cleaning and Repairing Radiator Fins

A radiator-fin comb is a specialized tool designed to straighten out bent radiator fins. Individual comb segments have different widths between teeth, since spacing between fins can vary among different radiators.



It's important to keep the radiator fins and AC condenser free of dust buildup, insects and other debris that can restrict airflow and thus diminish the overall effectiveness of the cooling system.

Figure A

A brush is one fairly effective means of cleaning debris from the intricate network of aluminum fins (figure A). Gently brush in one direction and dislodge any debris that's stuck between the fins. An easier and more effective technique is to use a burst of air from an air compressor.

Figure B

In order to prevent insects from clogging the fins in the first place, you may want to install a bug net (figure B). These mount on your front grill and are particularly beneficial in the spring and summer or if you live in a region of the country that's especially "buggy."

Figure C

Another condition that can impede airflow is bent radiator fins. Fins can become damaged by being struck by rocks during highway driving or by careless handling of the radiator during engine repairs. You can straighten out bent fins with a fine, sharp object such as an icepick (figure C), or you can use a specialized tool designed specifically for the job -- a radiator comb (figure D).

Figure D

Careful use of a radiator comb will help return bent fins to their proper shape and position. Be careful when using the comb, as the thin walls of the fins are delicate. This is a tedious job, so take your time and be patient.

RESOURCES :

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896

Safety Tips in the Car Park

Car parks are often regarded as high crime areas, with car thefts, window break-ins, and even abductions.

People usually blame a crime on the lack of security at the car park but there are times when such a case happens because of the people’s own carelessness.

Here are a few tips to be safe in the car park.

1. Be aware of suspicious characters loitering around before you enter your car.

2. If you sense something wrong while you are inside your car, sound the horn to grab attention.

3. Always make sure your car is locked and the windows are wound up.

4. Do not leave the ticket or coin chip in your car.

5. Never leave your valuable belongings in your car.

6. Do not park at an empty car park.

7. Take a picture of the pillar number where you park, in case you forget the location later.

8. Alternatively, store the pillar number as SMS in your cell phone.

9. You can always ask a security guard to accompany you to your car.

Cara menghidupkan kereta apabila bateri lemah

Pemilik kereta akan berasa gelabah apabila keretanya tidak boleh dihidupkan kerana bateri lemah atau ada masalah lain pada enjin. Kegelisahan bertambah ketara apabila masalah itu berlaku ketika anda terburu-buru untuk ke pejabat, hospital atau memenuhi temu janji.
Ada sebab mengapa enjin jika tidak dapat dihidupkan walau pun kunci sudah diputar ke arah ‘start’. Apabila enjin tidak dapat dihidupkan dengan mudah kerana bateri dan/atau motor starter dalam keadaan rosak, biasanya enjin dapat start dengan prosedur berikut:

1: Menghidupkan enjin dengan menolak kenderaan bagi kereta manual. Meskipun bateri dalam keadaan lemah, enjin akan dapat dihidupkan dengan cara menolak kenderaan apabila bateri sekurang-kurangnya masih dapat dapat menerangkan lampu besar.
Pertama, nyalakan suis kemudian mintalah bantuan dua atau tiga orang untuk menolak kenderaan anda ke depan. Apabila kenderaan sudah berjalan cukup cepat, maka lepaskan pedal. Apabila enjin sudah dapat berfungsi, pijaklah segera pedal sementara itu pijaklah pedal minyak untuk meninggikan putaran enjin. Menggunakan prosedur yang sama, kereta juga dapat dihidupkan dengan cara ditarik kenderaan lain. Apapun, prosedur kedua-dua teknik itu tidak dapat digunakan untuk kereta automatik.

2: Satu lagi cara ialah dengan menghidupkan enjin dengan pertolongan bateri dari kenderaan lain. Jika ada kenderaan lain dengan bateri yang baik dan tersedia kabel yang cukup panjang, maka enjin dapat dihidupkan dengan menghubungkan terminal positif dengan positif dan negatif dengan negatif dari kedua-dua kenderaan itu. Kaedah ini dapat dilakukan apabila kedua-dua bateri mempunyai kuasa yang sama. Ketika suis kontak starter diputar, lazimnya motor starter berfungsi tetapi ada ketikanya gandar enjin tidak berputar. Dan dalam keadaan lain pula, ketika suis kontak starter diputar, enjin dapat berfungsi tetapi tidak berjalan dengan baik dan kemudian mati dengan tiba-tiba. Dalam keadaan itu, antara kerosakan yang mungkin berlaku adalah kerosakan pada motor starter, gigi motor starter atau roda daya rosak. Kejadian itu bukan kali pertama terjadi. Dalam keadaan lain ketika suis kontak diputar, motor starter berfungsi dan gandar enjin berputar cepat tetapi enjin tidak dapat berfungsi atau ketika suis kontak starter diputar, enjin dapat berfungsi tidak berjalan dengan baik dan kemudian mati dengan tiba-tiba.

Dalam kedua-dua kes itu mereka mungkin berhadapan dengan kerosakan pada sistem penyaluran bahan bakar (sistem petrol) atau sistem penyalaan. Apabila motor starter berfungsi dan dapat memutar gandar enjin dengan baik, tetapi enjin tidak dapat berfungsi, maka hal itu menunjukkan kerosakan tidak berlaku pada bateri dan peralatan start. Biasanya, apabila proses mampatan dapat berjalan lancar, enjin tidak akan secara tiba-tiba rosak. Justeru, kerosakan harus dicari pada sistem penyaluran petrol dan sistem penyalaannya.

Bila keadaan itu terjadi, perkara yang harus diperiksa adalah: adakah minyak dalam tangki, adakah minyak dalam karburetor cukup? Jika cukup, ini bermakna kerosakan mungkin terletak pada sistem penyalaan.

Jika melimpah pula (karburator basah), enjin sukar dihidupkan kerana minyak yang masuk dalam ruang pembakaran terlalu banyak. Minyak melimpah biasanya terjadi kerana tutup jarum yang mengendalikan kemasukan minyak ke ruang pelampung (dalam karburator) tidak berfungsi, mungkin kerana tersekat habuk. Jika melimpah adalah sebab kegagalan enjin dihidupkan, keluarkan minyak daripada karburator, bersihkan kotoran di tutup jarum dan masuk semula minyak.

Enjin yang karburetor melimpah boleh dihidupkan dengan cara berikut. Pijak pedal petrol sepenuhnya, jalankan motor starter. Minyak yang masuk dari karburetor ke silinder melalui saluran isap dapat dihilangkan dan selepas itu enjin dapat berfungsi. Kawal injak minyak sedemikian sehingga putaran enjin terlalu tinggi. Meskipun demikian, ada kemungkinan enjin tidak dapat berfungsi, sedangkan karburetor tetap melimpah. Dalam hal ini, bawalah ke mekanik anda untuk dibaiki.

Penyerap Hentakan Rosak Boleh Menyebabkan Kemalangan Dan Kehausan Pada Tayar

Ketika memandu, pernahkah anda mengalami kereta melantun terlalu kuat apabila termasuk ke dalam lubang atau bonggol jalan? Kereta akan terasa melantun-lantun lebih daripada sekali sebelum kembali ke posisi yang asal.

Ada ketikanya kereta terasa membuai-buai dan sukar dikawal pada kelajuan tinggi di lebuh raya. Pemandu akan sering membetulkan posisi stereng ketika sedang mengambil selekoh. Situasi ini ada kaitan dengan penyerap hentakan atau ‘shock absorber’. Apa yang pasti ia adalah salah satu kompenan terpenting kenderaan yang membabitkan keselamatan dan keselesaan memandu. Penyerap hentakan yang rosak boleh menyebabkan kerosakan lain pada kenderaan dan di dalam kes yang lebih serius, mampu menyebabkan kemalangan. Pada kelajuan tinggi, kereta akan terasa bergerak tidak lurus dan anda terpaksa membetulkan kedudukan stereng terlalu kerap (OVER-CORRECT). Kereta juga akan terasa seperti “terapung” di atas jalan raya. Ini bermakna penyerap hentakan telah rosak dan perlu diganti dengan segera.

Cara mengenal pasti kerosakan penyerap hentakan kereta anda.

1. Tekan dengan kuat pada setiap sudut yang mempunyai penyerap hentakan dan lepaskan. Jika ia tidak kembali ke kedudukan asal ataupun ia tidak turun sewaktu ditekan, ini bermakna penyerap hentkan telah menjadi terlalu keras atau telah tersekat akibat tiada atau kurang pergerakan pada piston rod di dalam penyerap.

2. Anda juga boleh memeriksa secara visual pada penyerap hentak sehinggalah ke tapak pegas. Jika anda gunakan penyerap hentakan gas, ia masih akan mengeluarkan minyak jka bocor kerana penyerap hentakan jenis ini menggunakan minyak sebagai pelincir.

a. Yang paling penting adalah untuk membezakan lelehan minyak dengan wap gas yang mengumpul habuk pada penyerap hentakan kerana wap gas tersebut adalah normal dan bukannya tanda kerosakan.

3. Tayar yang kelihatan tidak rata dan berbonggol, membuktikan bahawa tayar kereta anda mendapat sentuhan pada jalan raya dengan tidak sekata. Ini juga bermakna bahawa system penyerap hentakan kereta anda (damper) telah gagal menolak atau menampung sentuhan tayar (contact-patch) secara sekata.

a. Oleh yang demikian, anda dinasihatkan untuk menukar penyerap hentakan kereta anda dan menggantikan tayar yang telah rosak demi keselamatan anda

Article contributed by AAM

Tyre Safety

Tyre Maintenance - Your Most Important Safety Item

Your tyres are the only contact between you and the road and, like your vehicle, they too require regular maintenance.

Tips

Check your tyre pressures regularly, once a fortnight is recommended and ideally when your tyres are cold. Inspect tread and sidewalls for cuts and abrasions, bulges, unusual wear and road damage.

If the tyre receives a severe impact, ask your tyre retailer to check for internal damage. Do not repair cuts in sidewalls of radial ply tyres.

Avoid using 'sealants' or other liquid preparations to prevent deflation. These may cause the valve to stick open slightly, causing pressure loss and indirectly causing corrosion of steel belts.
Driving on under inflated tyres is almost certain to cause serious damage, always inflate tyres to the suggested pressure.

Take action immediately to rectify any unusual sounds or vibrations. Tyre balance and vehicle wheel alignment should be checked regularly, (ie every 10,000km), especially if your tyres are subjected to rough roads or aggressive driving.

Tyre wear on front wheel drive vehicles is a little higher and therefore, attention to tyre pressures as well as rotation should be made on a regular basis.

Suspension

Suspension ialah asas mekanisme system hidraulik yang mengawal getaran spring, ia sebenar bukan menanggung keseluruhan bebanan atau mengembalikan kedudukan asal selepas pergerakan ke atas dan ke bawah, pembalikan Cuma boleh dibuat oleh spring sahaja. Oleh itu badan kenderaan “body” terletak diatas spring dan “suspension” yang mengawal pergerakan apabila spring menerima tekanan disebabkan oleh bonggol yang menyebabkan ia bergetar. “Suspension” mengawal pergerakan spring dalam kesemua arah ketika spring termampat atau ketika spring mengembang dan jumlah rintangan yang diperlukan dalam tiap-tiap arah “up-down” ditentukan oleh jenis dan saiz kenderaan tersebut.

Mengesan Kerosakan Pada Suspension

• Ketika anda sedang memandu kenderaan dan melanggar lopak atau bonggol, kenderaan anda akan bergegar dan kurang selesa. Ia adalah kerana “suspension” sudah tidak berfungsi (hilang keanjalan).
  

• Jika anda sedang memandu sambil mengambil selekoh tiba-tiba terasa kenderaan anda hilang kawalan dan tidak stabil, ini kerana “suspension” tersebut terlalu lembut, ini adalah kerana spring telah hilang keanjalan.
  

• Sekiranya anda mendapati tayar kenderaan anda menjadi tidak rata serta cepat haus ia adalah kerana ‘absorder’ dan spring tidak berfungsi dan menyebabkan segala gegaran akan diserap oleh tayar.
  

• Sekiranya terdapat bunyi seperti belagar (besi) ia adalah berkemungkinan “bush absorber” dan spring tidak menyerap gegaran antara casis dan spring.
  

• Sekiranya terdapat kerosakan berikut sila rujuk pada bengkel berdaftar atau pusat servis yang berdaftar.

Cara-Cara Penjagaan “Suspension”

• Untuk menjaga “suspension” anda tidak membawa bebanan yang berlebihan mengikut saiz dan jenis kenderaan.
  

• Sekiranya anda kerap membawa muatan pastikan anada membuat pemeriksaan pada “suspension” dan menggunakan “absorber” serta spring yang bersesuaian untuk tugas tersebut.
  

• Untuk menjaga “suspension” serta rim dan tayar, elakkan daripada melanggar lopak dan lubang serta tidak melalui jalan yang tidak rata.
  

• Sentiasa memastikan penjajaran tayar kenderaan di dalam keadaan baik
  

Article contributed by AAM

Intercoolers

Front mount intercooler

An intercooler’s purpose is to cool air that has compressed in either a turbo or supercharger. When air is compressed its temperature rises drastically, upwards of 300 degrees Fahrenheit, and becomes less dense and less oxygen rich. An intercooler is an essence a heat exchanger, like your radiator.
There are 2 main types of intercoolers air to air and air to water. An air to air intercooler uses outside air to transfer heat, while a air to water uses water to transfer heat.

In an air to air intercooler cool air passes through the intercooler tubes heating both the tubes and eventually the cooling fins. At the same time air from the outside passes through the fins of the intercooler, the heat from the tubes and fins is transferred to the air passing by on the outside. When it comes to an air to air intercooler setup there are different locations setups, different inlet and outlet configurations and different sizes. Locations for a front mount intercooler include, side mount intercooler and top mount intercooler. The location of the intercooler is key when determining how effectively it will transfer heat. The optimal location is a spot where the intercooler will have forced outside air blowing directly on it without any interference. This is why front mount intercoolers are very effective at transferring heat. They sit directly at the front of the car so they constantly have air from the outside blowing through the intercooler fins. Usually the only negative argument for a front mount intercooler is pressure drop. Pressure drop occurs because the route the air has to take to make it from the turbo to the front mount intercooler to the engine is long and not direct. Many front mount intercoolers today have been designed to help air flow and decrease pressure drop almost to a non-issue.

Top mount intercooler

Another cool setup I like is the hood scoop scooping in air directly to a top mount intercooler, like a Subaru Wrx. A major disadvantage to this is that your intercooler sits close to your engine which heats up your intercooler drastically reducing its efficiency for heat transfer. An advantage to this setup is that the air flow route from the turbo to intercooler to engine is short creating a more responsive setup.

A water to air intercooler is much like an air to air intercooler but this setup uses water to transfer heat instead of air. Since water is much better at transferring heat than air, you can have a smaller cooler which makes installing and finding an optimal location/setup much easier. In this setup water is pumped through the air/water unit where it meets the compressed air. Here the heat from the air is exchanged to the water. After the water has been heated it follows a path to a heat exchanger, like an intercooler or radiator where the heat is then transferred out of the water. Some obvious disadvantages that are inherent to a water-to-air setup are weight and mechanical malfunctions.

How Car Cooling Systems Work

Diagram of a cooling system: how the plumbing is connected

Although gasoline engines have improved a lot, they are still not very efficient at turning chemical energy into mechanical power. Most of the energy in the gasoline (perhaps 70%) is converted into heat, and it is the job of the cooling system to take care of that heat. In fact, the cooling system on a car driving down the freeway dissipates enough heat to heat two average-sized houses! The primary job of the cooling system is to keep the engine from overheating by transferring this heat to the air, but the cooling system also has several other important jobs.

The engine in your car runs best at a fairly high temperature. When the engine is cold, components wear out faster, and the engine is less efficient and emits more pollution. So another important job of the cooling system is to allow the engine to heat up as quickly as possible, and then to keep the engine at a constant temperature.

The Basics

Inside your car's engine, fuel is constantly burning. A lot of the heat from this combustion goes right out the exhaust system, but some of it soaks into the engine, heating it up. The engine runs best when its coolant is about 200 degrees Fahrenheit (93 degrees Celsius). At this temperature:

• The combustion chamber is hot enough to completely vaporize the fuel, providing better combustion and reducing emissions.
• The oil used to lubricate the engine has a lower viscosity (it is thinner), so the engine parts move more freely and the engine wastes less power moving its own components around.
• Metal parts wear less.

There are two types of cooling systems found on cars: liquid-cooled and air-cooled.

Liquid Cooling
The cooling system on liquid-cooled cars circulates a fluid through pipes and passageways in the engine. As this liquid passes through the hot engine it absorbs heat, cooling the engine. After the fluid leaves the engine, it passes through a heat exchanger, or radiator, which transfers the heat from the fluid to the air blowing through the exchanger.

Air Cooling
Some older cars, and very few modern cars, are air-cooled. Instead of circulating fluid through the engine, the engine block is covered in aluminum fins that conduct the heat away from the cylinder. A powerful fan forces air over these fins, which cools the engine by transferring the heat to the air.

Blow Off Valve - HKS Super Sequential

Ever wonder why rally cars make that sound you hear when you open a bottle of pop? Well, maybe not exactly like that but more or less similar to the sound of air being released (air, not gas!). You usually hear this when you let off the throttle, sorta sounds like a woosh!. In effect, what you are hearing is the sound of built up boost pressure being released from the intake system. The reason for this is that the turbocharger will keep spinning even after you let off the gas. So as you close the throttle plate, allot of pressure builds up in the intake system. This becomes problematic in that this excess pressure can cause the turbines to seize. Ultimately, this would destroy the turbo unit. For this reason, we incorporate BOV's, bypass or diverter valves. These mechanism work because on the other side of the throttle plate, vacuum gets built up in the intake manifold. Blow off valves, diverter and bypass valves all work by detecting this vacuum. Having done so, they use this vacuum to mechanically open a valve in order to relieve unnecessary boost from the other side of the throttle plate.

Forge Diverter/Dump Valve

Now let us differentiate BOV's, diverter and bypass valves. First, a blow off valve (seen top ) is common to high performance applications in that it provides the least bit of compromise. A BOV essentially releases this pressure straight out into the atmosphere. Quite often you will find that these units take on particular shapes, making them resemble musical instruments. I guess some people out there really like to flaunt their gadgets. Just wait ti'll you see how much they impress the ol' 5-0. Aside from this legal dilemma, the second problem you encounter with BOV's is that the mass air flow sensor will cause the engine management system to "think" that the air will go into the engine and in turn will release an appropriate amount of fuel for it. However, a BOV system will vent this air out before it gets to the injectors causing your mixture to run lean. In turn, this will result in unburned fuel to escape into the exhaust system. This is why you often see flames and hear those "pop's" in rally cars. It is unburned fuel exploding in the exhaust system. Doesn't take a genius to figure out that this is not the smartest application for the day to day car. For this reason, reasonable tuners will usually employ a bypass or a diverter valve (see left). These units essentially redirect this pressure back behind the compressor causing the net flow of air to remain constant. This in turn slows the turbine down gradually and allows the air flow sensor to work appropriately.

Working principle

A turbocharger consists of a turbine and a compressor linked by a shared axle. The turbine inlet receives exhaust gases from the engine exhaust manifold causing the turbine wheel to rotate. This rotation drives the compressor, compressing ambient air and delivering it to the air intake of the engine, resulting in a greater amount of the air/fuel mixture to enter into the cylinder. The objective of a turbocharger is the same as a normal supercharger; to improve upon the size-to-output efficiency of an engine by solving one of its cardinal limitations. A naturally aspirated automobile engine uses only the downward stroke of a piston to create an area of low pressure in order to draw air into the cylinder. Because the number of air and fuel molecules determine the potential energy available to force the piston down on the combustion stroke, and because of the relatively constant pressure of the atmosphere, there ultimately will be a limit to the amount of air and consequently fuel filling the combustion chamber. This ability to fill the cylinder with air is its volumetric efficiency. Because the turbocharger increases the pressure at the point where air is entering the cylinder, and the amount of air brought into the cylinder is largely a function of time and pressure, more air will be drawn in as the pressure increases. The additional air makes it possible to add more fuel, increasing the output of the engine. Also, the intake pressure can be controlled by a wastegate, which controls boost by routing some of the exhaust flow away from the exhaust side turbine. This controls shaft speed and regulates boost pressure in the inlet tract.

The application of a compressor to increase pressure at the point of cylinder air intake is often referred to as forced induction. Centrifugal superchargers operate in the same fashion as a turbo; however, the energy to spin the compressor is taken from the rotating output energy of the engine's crankshaft as opposed to exhaust gas. For this reason turbochargers are ideally more efficient, since their turbines are actually heat engines, converting some of the thermal energy from the exhaust gas that would otherwise be wasted, into useful work. Contrary to popular belief, this is not totally "free energy," as it always creates some amount of exhaust backpressure which the engine must overcome. Superchargers use output energy from an engine to achieve a net gain, which must be provided from some of the engine's total output; either directly or from a separate smaller engine, perhaps electrically driven from the main engine's generator.

Enter the dragon

Now we're torn. Yesterday we saw the Aston DBR9 Le Mans racer in Gulf livery and were certain we'd found the coolest racing car of the year.

But now Nissan has gone and taken the wraps off the awesome GT500 GT-R, in Tokyo, and we're all torn.

Because, well, just look at it. The GT500 is, as you might have guessed, a racing version of the GT-R (Top Gear's Supercar of the Year, no less), set to compete in Japan's Super GT Championship.

It'll race in the top category, the GT500 - quite possibly the fastest GT series in the world thanks to a list of regulations that reads something like: 'Do more or less whatever you want, so long as you keep under 500bhp.'

As the road-going GT-R puts out some 480bhp, that means it won't be much more powerful on paper. But, as a quick look at (and, more important, a quick listen to) this video of the car in testing reveals, there has been some pretty serious work put into the GT-R's 3.8-litre twin-turbo V6. What a noise.

Watch the GT500 on YouTube

Nissan hasn't released any technical details on the GT500 yet, but we do know that it won't be allowed traction control, ABS or stability control. Whoever takes control of that thing needs cojones of carbon fibre.

The organisers of the Super GT confidently assert that over the past few years, they've introduced more stringent regulations regarding aerodynamics, aiming to bring GT500 cars in line with GT1 cars. By the looks of the rear end of the GT500, those regulations aren't too strict yet: look at the size of that rear wing and diffuser.

The GT500 also shows off Nissan's new works livery, which owes much to the paintjob on the current Fairlady Z race car. According to the Nissan spiel, 'the red symbolises the passion for racing, while the black signifies the high performance of the new GT-R'.

Even if you painted the GT500 pink and plastered it in fluffy bunny decals, it'd still look scary enough to make Ross Kemp weep. We'll find out more about the GT500 GT-R at the end of this month.

How to Save Money on Fuel

Step

1. Don't drive. Don't drive a car when you don't have to. Ridesearch or Carpool, walk, take the bike, or take a bus. These will not only save gas, but also will help save our environment and may be better for your health. Do you really need to drive to the store that is only a couple of blocks down the street?
2. Get a credit card. Some right credit cards offer gas savings when you use the card for purchases. This works in much the same way that some credit card companies allow you to earn frequent flyer miles when you use their card for purchases. But watch for interest rate charges. However, some stations still charge a higher rate for using a credit card.
3. Get a better air filter. More efficient brands of air filters cost a little more but will pay for themselves in most vehicles in fuel savings.
4. Get Low Resistance Tires. Some tires, such as Michelin Energy MX 4 Plus are supposed to increase gas mileage.
5. Give your car a tune up. While properly maintaining your car won't actually save you money at the pump, it will save you gas. Using less gas saves you money. Have the oil changed, and have a certified mechanic give your engine a look over.
6. Buy a hybrid car. Not only do hybrid cars give you immediate savings at the pump, the U.S. government and your local state offer tax breaks for people who use gas-saving cars. Federal deductions for using gas-saving cars can be as high as $2,000.00, but check before buying to see if they're still in effect. If you can't afford the growing number of hybrid cars out there, consider getting a regular car with good MPG (miles per gallon). In general, the smaller the car, the better the mileage.
7. Reduce your commute. Move closer to work, work closer to home, or take public transportation to your job. While you're considering spending all that money on a new hybrid or diesel vehicle to 'save money', you could move closer to your job, or get a job closer to your home. Then you will be able to walk or ride a bike on nice days, and spend a lot less time in the car when the weather isn't so nice. You may even be able to get rid of one family car. If you walk or ride almost all the time, it doesn't matter what sort of mileage your current car gets while it collects dust in the driveway.
8. Avoid idling. While idling, your car gets exactly 0 miles per gallon. Although starting the car used to use a lot of gas, it's now the same as idling for about 30 seconds. Idling to warm up is particularly bad, as the engine needs extra fuel to warm up. After start up, allow your car to idle 15-30 seconds, then drive conservatively until it reaches normal operating temperature. Park your car and go into the restaurant rather than idling in the drive-through. Idling with the air conditioning on also uses extra fuel.
   • Stopping and starting the engine frequently will cause extra wear. Don't stop the engine if you are going to idle for less than a minute.
   • In very cold environments, it is recommended to allow the vehicle to idle and warm up, rather than just start it and take off. You might save gas, but your engine oil won't do its job until it's fully liquid, so you'll spend more money on overhauls.
9. Plan your trips in advance. This can prevent wasting fuel and wasting time. Plan to use alternative routes. Often back roads can prevent you from stopping at traffic lights and more importantly sitting in traffic jams.
10. Check the tire air pressures weekly. Buy an inexpensive air pump and an accurate tire gauge (not a pencil gauge as they are not accurate). Keep all tires inflated to the pressure as recommended for your car. Go by the tire wall; the sticker on the door frame, fuel filler flap, or manual is for comfort, not fuel efficiency. Generally speaking, a slightly higher pressure will improve fuel mileage and handling, but too high will degrade traction and wear the tires rapidly.
11. Drive at a consistent speed. Avoid high acceleration and hard braking. Use cruise control when you can.
12. Clean out any unnecessary items in your car. If you have heavy objects in your car that you don't need, remove them. If your car is lighter, it will use less fuel to get where you're going.
13. Slow down. Air resistance goes up as the square of velocity. The power consumed to overcome that air resistance goes up as the cube of the velocity. Rolling resistance is the dominant force below about 40 mph. Above that, every mph costs you mileage. Go as slow as traffic and your schedule will allow. Drive under 60-65 since air grows exponentially denser, in the aerodynamic sense, the faster we drive. To be precise, the most efficient speed is your car's minimum speed in it's highest gear, since this provides the best "speed per RPM" ratio.