How a car engine works

In this article we will discuss very briefly how a typical car engine works in terms of generating power required to move the vehicle.

The most common type of car engine is an internal combustion gasoline engine working on the principal of the Otto cycle. The simple animation below provides a rough illustration of what is happening in the 4 cylinders of a standard gas motor.



If you analyze the animation then you will see the basic principle of operation which consists of 4 steps performed in each of the cylinders. These are:

1. A fuel air mixture is pulled into a cylinder (where fuel usually enters through a special fuel injector). In the illustration above, the mixture enters through the blue intake valve.

2. The cylinder is then sealed off with both the intake and outlet valves closed and the piston moves upward to compress the mixture required for effective combustion.

3. A spark is then generated by a special spark plug and the mixture is ignited with the burning gas pressure pushing the piston down. This generates power to rotate the crankshaft inside the engine block.

4. Finally, the exhaust valve opens and the piston moves upward to release the exhaust gasses.

This process is continuously repeated in all 4 cylinders while the engine is running. The 4 stokes are also known as: 1. Intake stroke. 2. Compression stroke. 3. Power stroke. 4. Exhaust stroke.

Below is a more detailed animation of a cylinder/valve/piston operation:



Depending on the particular engine design there can be several cylinders-pistons in a car engine (usually there are 4-12). A special connecting rod links the pistons to a crankshaft which is rotated inside the engine block. The crank is used to convert the linear piston motion to rotation.

The following video provides a very good explanation to some of the basics behind the car engine operating principles:




http://www.carsensation.com

Pembakaran Sempurna dan Tidak Sempurna

Pembakaran bahan bakar dalam mesin kendaraan atau dalam industri tidak terbakar sempurna. Pembakaran sempurna senyawa hidrokarbon (bahan bakar fosil) membentuk karbon dioksida dan uap air. Sedangkan pembakaran tak sempurna membentuk karbon monoksida dan uap air. Misalnya:

a. Pembakaran sempurna isooktana:

C8H18 (l) +12 ½ O2 (g) –> 8 CO2 (g) + 9 H2O (g) ΔH = -5460 kJ

b. Pembakaran tak sempurna isooktana:

C8H18 (l) + 8 ½ O2 (g) -> 8 CO (g) + 9 H2O (g) ΔH = -2924,4 kJ

Dampak Pembakaran tak Sempurna

Sebagaimana terlihat pada contoh di atas, pembakaran tak sempurna menghasilkan lebih sedikit kalor. Jadi, pembakaran tak sempurna mengurangi efisiensi bahan bakar. kerugian lain dari pembakaran tak sempurna adalah dihasilkannya gas karbon monoksida (CO), yang bersifat racun. Oleh karena itu, pembakaran tak sempurna akan mencemari udara.


Bambang Sugianto

Nilai Panas Busi

• Nilai panas adalah kemampuan meradiasikan sejumlah panas oleh busi.
• Busi yang meradiasikan panas lebih banyak disebut "busi dingin". Sebaliknya yang meradiasikan panas sedikit disebut "busi panas".
• Busi akan maksimum bila elektroda tengahnya mempunyai temperatur antara 4500C dan 9500C.
• Batas operasional terendah dari husi disebut self cleaning temperatur. Sedangkan batas tertinggi disebut preignition temperatur.
• Untuk membedakan antara busi dingin dan busi panas dapat dilihat dari panjang ujung insulator.
• Busi dingin mempunyai ujung insulator yang lebih pendek sedangkan busi panas ujung insulatornya panjang.

Few basics of car care and maintenance...

Most of us know the agony of having your car break down in the middle of nowhere or on the way to work. You have gone through it and so have I, and let me tell you it was one painful and long day. However, an auto repair shop was nearby and that sort of came to the rescue. I say ’sort of’ because for basic auto repair they charged me a bundle. Not many will tell you this but as important as knowing a family doctor is, I feel it is equally important to know professional auto repair services.

Now, I am not suggesting you start building new relationships immediately, but you definitely need to know the basics on the mechanism, and working of your automobile. Listed below are necessary pointers, to give you an idea of the basics of car care and maintenance, that will boost and improve your auto repair IQ while also helping you make better choices about your car.


* Synthetic Oil is just a poorer alternative and not always better. If your car has been functioning smoothly with regular oil, and your car’s manual doesnt suggest a change, stick to regular oil for all your oil change requirements. The main reason why auto shops ask you to change is to only make quick money.

* Get a new timing belt on recommended intervals. A timing belt does not have warnings or symptoms but when it breaks, and depending on the kind of engine your car runs on, it can cause substantial internal wreckage. This results in your car’s pistons crashing into valves.

* While changing your timing belt, switch your serpentine belt or drive belts too as it can save all your future labor charges. Serpentine or drive belts should be taken out in order to complete the timing belt’s replacement.

* Want long lasting and long performing windshield wipers? Use alcohol and a soft rag while cleaning your windshield wipers to improve its performance and also to extend its life.

* Know how to check all the fluid levels in your car Engine coolant, engine oil, power steering fluid, transmission fluid, washer solvent and brake fluid, all show fluid levels. An indicator of forthcoming problems is dropping fluid levels.

* Regularly check your brake pad’s life. Switch the pads before they are exhausted and begin to grind into your vehicle’s brake rotors which will further increase price of brake repair.

* Always clean your car’s battery posts.

* Know that every different automobile has a different duration for the change of the cars spark plugs. Read your vehicles manual to know about your cars interval time. To make extra money, deceitful auto mechanics may suggest switching spark plugs after every 30,000 miles even if your car’s spark plugs’ life expectancy may be 100,000 miles.

* Check the pressure of your tires frequently. If your tyres are inflated to the right pressure, it saves fuel and also lengthens the tire longevity. On the other hand, lessening tyre air pressure means a leak that needs immediate repair.

* Regularly check your air filters. Filthy air filters reduce fuel economy and functioning. A high-pressure hose can be used to blow-out dirty air filters instead of getting new ones.

* Keep an eye on your engine oil. Check your engine oil regularly. Older automobiles may start to burn oil. Sometimes, cars can run dangerously low on engine oil and not show any warning of a leak.

To be realistic, many of us will never make efforts to learn how to work on our own cars. Most of the cars that came out within the last decade are run by a variety of electronic sensors and computers. The positive bit about this is that the auto industry is always making changes to improve fuel economy, lessen pollution, and provide optimum performance all by itself. On the other hand, vehicles need regular specialized training, and exorbitant testing equipments in order to flawlessly determine problems and repair cars.

Without this necessary training and contribution in specialized car tools, the DIY car owner, (and even smaller auto repair shops) has no other option but to throw parts at cars until the warning signs disappear. In some situations, auto shops replace a certain part, and later also suggest after the installation that another part too requires changing. If it was never mentioned in the beginning, this is an alarm bell that the mechanic isnt accomplished enough to recognize the problem effectively. With a bad mechanic, you might have just replaced parts that were working perfectly well.

This is the main reason we state that the most crucial choice you make in getting your car fixed is which auto repair shop you take your car to. As many honest and skilled mechanics there are, also present are deceptive and dishonest mechanics too. We suggest you ask your friends and neighbors to recommend you a mechanic, else use a 3rd party service like AAA, the Better Business Bureau, or CompareAutoCare.com to provide you with information on shops in your local area, so that you have an idea of what youre stepping into before you actually bring in your vehicle for service.

Mostly, enjoy your ride.

Author: Curry Jasper
Article Source: EzineArticles.com

Mesin Masih Hidup Walaupun Kunci Kontak sudah "OFF"

Mencegah dieseling pada mesin bensin Coba perhatikan berapa lama waktu yang dibutuhkan mesin mobil Anda untuk benar-benar mati? Mestinya, begitu kunci kontak kita putar ke posisi OFF, putaran mesin tak dengar lagi. Kalaupun berputar, cukup 1 sampai 2 putaran saja. Bila mesin masih berputar lebih lama dari itu, harap sedikit waspada. Barangkali mobil Anda mengalami dieseling.

Dieseling adalah masih berputarnya mesin secara berlebihan setelah kunci kontak diposisikan off. Kasus ini terjadi pada mesin berbahan bakar bensin. Gejala ini tergolong kondisi yang tidak normal. Secara teknis, mesin seharusnya langsung mati ketika kunci kontak kita posisikan OFF. Sebab, pada saat itu supply bensin terputus dan percikan api dari busi padam. Artinya, pembakaran di ruang bakar terhenti dan mesin tak mendapat energi untuk berputar.

Selama ini banyak pengendara yang menganggap ringan bila mendapati mesin bensin yang masih berputar meskipun telah dimatikan. Seolah, kasus semacam ini tidak terlalu berpengaruh pada kenyamanan dan keselamatan berkendara. Padahal, kalau kita perhatikan baik-baik, dampak-dampak dieseling sebenarnya sangat banyak.

Memperpendek usia busi. Ini akan terjadi karena busi mobil yang mengalami dieseling cenderung basah. Kondisi yang basah ini memudahkan terjadinya hubungan singkat (korsleting) pada busi. Bila sudah seperti ini, busi akan cepat panas yang kemudian akan mempercepat retaknya busi atau putusnya resistant (tahanan) pada busi.

Dieseling juga menunjukkan bahwa pembakaran tidak sempurna. Ini berarti dieseling akan dapat mempercepat timbulnya kerak karbon pada ruang bakar.

Efek berikutnya, mesin ngelitik dan mempercepat keausan pada mesin (piston, silinder mesin, ring piston). Mesin yang mengalami dieseling pada umumnya akan lebih susah dihidupkan. Sebab, pada ruang bakar biasanya terdapat terlalu banyak bahan bakar. Lama kelamaan ini akan membuat aki soak.

Berikutnya adalah efek pada engine mounting. Dieseling indentik dengan putaran mesin yang tidak stabil. Dengan ketidakstabilan putaran mesin maka mounting akan meredam getaran mesin secara tidak stabil pula. Ini yang akan mempercepat retak atau kerasnya mounting mesin.

Secara teknis, beberapa hal yang menjadi pemicu dieseling, diantaranya adalah: Pertama, sistem cut-off bahan bakar tidak berfungsi dengan baik; Kedua, kerak karbon pada ruang bakar yang berlebihan sehingga menimbulkan bara pada ruang mesin; dan Ketiga, (yang berasal dari unsur perilaku pengendara) dieseling muncul karena saat mematikan mesin pengendara terbiasa menginjak pedal gas.

Dari tiga penyebab itu, kita dapat mengetahui apa-apa saja yang dapat kita lakukan agar mesin mobil kita tidak mengalami dieseling. Hindari menginjak pedal gas saat mematikan mesin. Periksa sistem cut-off bahan bakar. Perbaiki bila masih terjadi kebocoran aliran bahan bakar. Bersihkan kerak ruang bakar mesin secara periodik, alangkah baik setiap 80.000 km atau dengan menggunakan bahan additive pembersih ruang bakar yang banyak dijual di bengkel-bengkel.

Sumber : Tabloid Otomotif