oxygen sensors

Automotive oxygen sensors, colloquially known as O2 sensors, make modern electronic fuel injection and emission control possible. They help determine, in real time, if the air–fuel ratio of a combustion engine is rich or lean. Since oxygen sensors are located in the exhaust stream, they do not directly measure the air or the fuel entering the engine. But when information from oxygen sensors is coupled with information from other sources, it can be used to indirectly determine the air-fuel ratio. Closed loop feedback-controlled fuel injection varies the fuel injector output according to real-time sensor data rather than operating with a predetermined (open-loop) fuel map. In addition to enabling electronic fuel injection to work efficiently, this emissions control technique can reduce the amounts of both unburnt fuel and oxides of nitrogen entering the atmosphere. Unburnt fuel is pollution in the form of air-borne hydrocarbons, while oxides of nitrogen (NOx gases) are a result of combustion chamber temperatures exceeding 1,300 kelvin due to excess air in the fuel mixture and contribute to smog and acid rain. Volvo was the first automobile manufacturer to employ this technology in the late 1970s, along with the three-way catalyst used in the catalytic converter.

The sensor does not actually measure oxygen concentration, but rather the difference between the amount of oxygen in the exhaust gas and the amount of oxygen in air. Rich mixture causes an oxygen demand. This demand causes a voltage to build up, due to transportation of oxygen ions through the sensor layer. Lean mixture causes low voltage, since there is an oxygen excess. Modern spark-ignited combustion engines use oxygen sensors and catalytic converters in order to reduce exhaust emissions. Information on oxygen concentration is sent to the engine management computer or ECU, which adjusts the amount of fuel injected into the engine to compensate for excess air or excess fuel. The ECU attempts to maintain, on average, a certain air–fuel ratio by interpreting the information it gains from the oxygen sensor. The primary goal is a compromise between power, fuel economy, and emissions, and in most cases is achieved by an air-fuel-ratio close to stoichiometric. For spark-ignition engines (such as those that burn gasoline, as opposed to diesel), the three types of emissions modern systems are concerned with are: hydrocarbons (which are released when the fuel is not burnt completely, such as when misfiring or running rich), carbon monoxide (which is the result of running slightly rich) and NOx (which dominate when the mixture is lean). Failure of these sensors, either through normal aging, the use of leaded fuels, or fuel contaminated with silicones or silicates, for example, can lead to damage of an automobile's catalytic converter and expensive repairs. Tampering with or modifying the signal that the oxygen sensor sends to the engine computer can be detrimental to emissions control and can even damage the vehicle. When the engine is under low-load conditions (such as when accelerating very gently, or maintaining a constant speed), it is operating in "closed-loop mode." This refers to a feedback loop between the ECU and the oxygen sensor(s) in which the ECU adjusts the quantity of fuel and expects to see a resulting change in the response of the oxygen sensor. This loop forces the engine to operate both slightly lean and slightly rich on successive loops, as it attempts to maintain a mostly stoichiometric ratio on average. If modifications cause the engine to run moderately lean, there will be a slight increase in fuel economy, sometimes at the expense of increased NOx emissions, much higher exhaust gas temperatures, and sometimes a slight increase in power that can quickly turn into misfires and a drastic loss of power, as well as potential engine damage, at ultra-lean air-to-fuel ratios. If modifications cause the engine to run rich, then there will be a slight increase in power to a point (after which the engine starts flooding from too much unburned fuel), but at the cost of decreased fuel economy, and an increase in unburned hydrocarbons in the exhaust which causes overheating of the catalytic converter. Prolonged operation at rich mixtures can cause catastrophic failure of the catalytic converter (see backfire). The ECU also controls the spark engine timing along with the fuel injector pulse width, so modifications which alter the engine to operate either too lean or too rich may result in inefficient fuel consumption whenever fuel is ignited too soon or too late in the combustion cycle. When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensor is ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage. This is referred to as an engine running in 'open-loop mode'. Any changes in the sensor output will be ignored in this state. In many cars (with the exception of some turbocharged models), inputs from the air flow meter are also ignored, as they might otherwise lower engine performance due to the mixture being too rich or too lean, and increase the risk of engine damage due to detonation if the mixture is too lean. source

Inilah Sensor Gerak untuk PC Pertama di Dunia

Asus memperkenalkan cara baru menikmati hiburan di televisi dan PC. Jika Anda biasa menggunakan remote control atau controller nirkabel, Asus WAVI Xtion (baca: way-vee action) justru mengadopsi teknologi sensor gerak pertama di dunia.

Ya, dengan teknologi anyar itu, penggunanya dapat memainkan game di PC, memutar hiburan multimedia di rumah hanya dengan input gestur tubuh yang intuitif pada layar Full HD.

Asus WAVI Xtion terdiri dari dua komponen, yaitu perangkat media streaming nirkabel WAVI, dan sensor gerak Xtion.

WAVI mampu menampilkan media high definition secara nirkabel dari sebuah PC ke TV di ruangan yang berbeda. Ia juga menandai munculnya antarmuka sensor gerak untuk memutar multimedia, bermain game, dan aplikasi lain berbasis gestur.

Sementara WAVI Xtion memadukan teknologi sensor gerak dari PrimeSense dengan antarmuka pengguna ASUS Xtion Portal melalui interaksi aplikasi yang intuitif.

Anda tahu konsol Nintendo Wii? Cara kerja WAVI Xtion kurang lebih sama dengannya. Hanya saja jika Wii menggunakan controller nirkabel, WAVI Xtion tidak sama sekali. Benar-benar berdasarkan gerak gestur tubuh gerak yang tertangkap sensor kamera.

Sementara itu koneksi PC dan TV menggunakan HDMI nirkabel (teknologi WHDMI), yang memberikan transfer data untuk menampilkan konten high definition seperti film, game, dan foto pada frekuensi 5 GHz dengan jangkauan mencapai 25 meter.

Berikut ini video singkat tentang Asus WAVI Xtion yang diunggah Network World

Komputer 3 In 1 Pertama Di Dunia Dari Gigabyte

Kebayang nggak kalo kamu punya notebook, tablet PC dan sebuah Desktop PC digabung menjadi satu? Gigabyte merealisasikan penggabungan tiga perangkat tersebut dan diberi nama Gigabyte Booktop T1125. Dan perangkat 3-in-1 ini diklaim sebagai yang pertama di dunia. Bentuk dasar Booktop T1125 ini merupakan sebuah notebook berlayar 11,6 inci dan memiliki swivel, yang artinya layarnya bisa diputar dan bisa berubah bentuk menjadi sebuah tablet PC. Nah, dengan bantuan Docking system, Booktop T1125 bisa berubah menjadi Desktop PC. Meski dengan bantuan docking sistem bisa menjadi Desktop PC, kamu tetap membutuhkan piranti pendukung seperti keyboard dan mouse. Tapi, kalau kamu ingin pergi ke kampus tapi ingin bawa notebook, nggak perlu lagi kamu matikan dan tinggal cabut saja dari docking system tersebut. Gigabyte T1125 memiliki spesfikasi seperti port USB 3.0 & HDMI serta eSATA, Prosesor Intel Core i5/ i3, Sistim operasi Windows 7, memory RAM 2 GB, kapasitas penyimpanan 320 GB dan webcam 1,3 MP. Menurut kabar yang beredar, Gigabyte Booktop T1125 akan beredar akhir November ini dengan harga sekitar USD. 1.299.

Intel Quad Core Desktop

Keluarga prosesor terbaru dari Intel Penryn yang di keluarkan pada November 12 kemarin, telah di perkecil ukuranya menjadi 45 nanometers atau bisa di bandingkan dengan 1/18000 dari lebar rambut manusia. penurunan dari proses manufaktur 65nm Intel mengembangkan dari Core line sebelumnya 90nm process yang digunakan pada pentium 4. selain itu Intel juga telah mempublikasikan teknologi yang akan dikembangkan di 2 tahun mendatang yaitu 32nm, sehingga dengan memperkecil ukuran transistor ini CPU intel akan memiliki sedikit ruang yang baru untuk menambahkan sistem baru di silikon processornya.
Seperti hal nya dengan produk Dual core yang sebelumnya produk terbaru dari Intel ini tetap akan mempublish 2 dual-core CPUs yang akan dipasangkan pada silikon tunggal dengan bus yang di pisah berjalan pada 1333 MHz. Masing-masing dari dual-core CPUs ini membawa 6MB cache dan untuk (L2) cache sampai 4MB pada masing masing core pada QX6850 chip, hingga CPU ini memiliki cache total 12MB.
QX9650 yang merupakan Penryn chip pertama yang akan digunakan pada desktop mengusung teknologi quad core CPU yang di targetkan untuk para enthusiasts dan yang memerlukan processor dengan kinerja tinggi selain itu Intel juga tidak mengunci prosesornya, sehingga siapapun dapat meng over-clock processor tersebut ( sebuah tantangan baru bagi AMD ) untuk beberapa bagian penting lainya, processor ini lebih terasa pada beberapa high end games dan high-end audio atau video yang mampu mengambil manfaat dari 4 core ini.