Ada satu sistem dalam kereta anda yang di kawal oleh ‘kumpuer kecil’ yang di pasang bagi mengawal ‘fuel injector’ supaya ia dapat mengimbangi campuran minyak dan udara sewaktu pembakaran. Apabila anda laju, udara masuk banyak maka ‘kumpuer’ ini akan mengarahkan fuel masuk banyak seimbang dgnnya. Jadi apabila kereta anda dipasang dgn hydrogen booster, tentulah gas hydrogen dan udara itu akan masuk banyak, maka ‘kumputer’ ini pun akan mengarahkan fuel masuk banyak sama – sudah tentunya penjimatan tidak berlaku. Oleh itu apabila alat EFIE/MAP ini di pasang, ianya berfungsi ‘menipu’ signal yang sampai ke’kumputer’ itu mengatakan gas dan udara tak masuk banyak pun….jadi ‘kumputer’ itu pun tidaklah mengarahkan fuel masuk banyak, dengan demikian baru lah berlaku penjimatan !!!
Cara lain ‘menipu’ ‘kumputer’ ni ada di buat oleh backyard engineer seperti di sebutkan dalam tajuk: PERTANYAN LAZIM.
MAP & EFIE.
Some cars use map. A manifold absolute pressure sensor (MAP) is one of the sensors used in an internal combustion engine‘s electronic control system. Engines that use a MAP sensor are typically fuel injected. The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine’s electronic control unit (ECU). This is necessary to calculate air density and determine the engine’s air mass flow rate, which in turn is used to calculate the appropriate fuel flow. (See stoichiometry.)
An engine control system that uses manifold absolute pressure to calculate air mass, is using the speed-density method. Engine speed (RPM) and air temperature are also necessary to complete the speed-density calculation. Not all fuel injected engines use a MAP sensor to infer mass air flow, some use a MAF sensor (mass air flow). Several makes use the MAP sensor in OBD II applications to test the EGR valve for functionality. Most notably General Motors uses this approach.
Some use EFIE.
Almost all modern vehicles, either fuel injected or carbureted, employ oxygen sensors to tell the vehicle’s computer if the air/fuel mixture is too rich or too lean. The computer uses the information from the 02 sensor to determine if more or less fuel should be added to the mix in order to maintain the correct proportion.
Most vehicles are designed to operate at an air/fuel ratio of 14.7 to 1. When these proportions are being supplied to the engine, a certain amount of oxygen will be detected in the exhaust by the 02 sensor, and this information is fed into the vehicle’s computer. If more oxygen is sensed, the computer thinks the mixture is too lean (not enough fuel), and adds fuel to the mix. Likewise, if less oxygen is sensed, the computer thinks the mixture is too rich (too much fuel) and cuts back on the fuel fed to the engine. This is actually an artificial relationship, but has been found to be workable with the existing techniques of burning fuel in your car’s engine.
There’s a big problem with this scenario as soon as you start adding a workable fuel efficiency device. For any given air/fuel ratio, burned more efficiently, the oxygen content in the exhaust will rise. If you have two or more efficiency devices installed, even more oxygen will be present in the exhaust. The oxygen content rises as the fuel is burned more efficiently for a number of reasons. Chief amongst these are a) less fuel is being used to produce an equivalent amount of horsepower, and b) less oxygen is being consumed to create carbon monoxide in the exhaust. The bottom line is there is more oxygen in the exhaust as the fuel burning efficiency is increased.
So, now that we have spent time and money to install a fuel efficiency device or two, and we are getting a more efficient fuel burn, what does the vehicle’s computer do? It dumps gas into the mix in an attempt to get an oxygen reading in the exhaust equal to it’s earlier, inefficient setup. This will then negate the fuel savings of just about any efficiency device, and in some cases will actually cause an increase in fuel consumption, despite having a workable fuel efficiency device.
The handling for this situation is simple. The signal coming from the 02 sensor needs to be adjusted to compensate for the increased fuel efficiency being achieved. Basically we need to fool the computer into thinking that the engine is still burning gas inefficiently, by making it think there is less oxygen in the exhaust than there actually is. The amount of change to the signal has to be easily adjustable to accommodate different amounts of efficiency increase from the varying types of efficiency devices that are available.
It should be noted that an oxygen sensor handling device, by itself, is not a fuel efficiency device. It possibly could be used to control the vehicle’s computer, and make the engine burn a little leaner, and this could possibly give a small increase in gas mileage. But this is not what it was designed to do. It was designed to complement, and in some cases make possible, increased gas mileage using other fuel efficiency devices.
In the past, fuel savers would not work when applied to fuel injection because those systems are actually designed to prevent efficient combustion!
Increasing the combustion efficiency of an engine increases the exhaust oxygen percentage. Most fuel injection engines use an oxygen sensor to infer the air/fuel ratio of the engine, the increased oxygen content in the exhaust is ‘read’ by the computer to be a lean mixture in the engine. The computer then adds extra fuel to bring the pollution back to ‘normal’.
This problem led to the development of the Electronic Fuel Injection Enhancer (EFIE, pronounced Ee-Fy). The EFIE allows you to apply an offset to the voltage coming from the oxygen sensor, so your vehicle’s computer is completely unaware that the oxygen content of the exhaust has increased.
The EFIE Manual explains exactly How to build an EFIE, using parts from a electronic store. The manual also completely details oxygen sensor function and why the EFIE
An Electronic Fuel Injection Enhancer is used to adjust the signal from the oxygen sensor(s) before they get to the engine’s computer to compensate for an increase in fuel efficiency brought about by another fuel efficiency device. The single version handles one oxygen sensor. The EFIE is not intended to be a fuel saver by itself. You should install a device that is designed to get more energy out of the same fuel, such as a hydrogen gas electrolyzer, a fuel vapor production unit, or other device that gets more power out of the same fuel by increasing the efficiency of the burn.
Although all cars sold today have electronic fuel injection systems, earlier automobiles had carburetors, which were less efficient. Some other types of small engines, such as lawnmowers or rototillers, still use carburetors. Both the carburetor and the electronic fuel injection system are mechanisms that supply fuel to the engine.
The first fuel injection systems were throttle body fuel injection systems, or single point systems, which had an electrically controlled fuel injector valve. Later, these were replaced by more efficient multi-port fuel injection systems, which have a separate fuel injector for each cylinder. The latter design is better at metering out fuel accurately to each cylinder, and also provides for a faster response.
Although electronic fuel injection is much more complicated than a carburetor, it is much more efficient. The injector is a type of valve that is controlled electronically, which opens and closes and supplies atomized fuel to the engine. It sprays fuel into the intake valves directly in the form of a fine mist. The injector opens and closes rapidly, and the pulse width, or the amount of time it stays open, determines how much fuel goes into the valve. Fuel is supplied to the injectors by a fuel rail.
Several sensors are included as part of the system, to ensure that the correct amount of fuel is delivered to the injectors, and then to the intake valves. These sensors include an engine speed sensor, voltage sensor, coolant temperature sensor, throttle position sensor, oxygen sensor, and airflow sensor. In addition, a manifold absolute pressure sensor monitors the air pressure in the intake manifold to determine the amount of power being generated.
In a sequential fuel injection system, the injectors open one at a time, in conjunction with the opening of each cylinder. Some other injection systems may open all injectors simultaneously. The sequential option is advantageous because it allows for faster response when the driver makes a rapid change.
The entire injection system is controlled by an electronic control unit (ECU), which functions as a central exchange for information coming in from all the various sensors. The ECU uses this information to determine the length of pulse, spark advance, and other elements. The ECU has several safety features built in, including a fuel cut parameter and top speed parameter.
Fuel injection is a system for mixing fuel with air in an internal combustion engine. It has become the primary system used in automotive engines, having almost completely replaced carburetors in the late 1980s.
A fuel injection system is designed and calibrated specifically for the type(s) of fuel it will handle: gasoline (petrol), Autogas (LPG, also known as propane), ethanol, methanol, methane (natural gas), hydrogen or diesel. The majority of fuel injection systems are for gasoline or diesel applications. With the advent of electronic fuel injection (EFI), the diesel and gasoline hardware has become similar. EFI’s programmable firmware has permitted common hardware to be used with multiple different fuels. For gasoline engines, carburetors were the predominant method to meter fuel before the widespread use of fuel injection. However, a wide variety of injection systems have existed since the earliest usage of the internal combustion engine.
The primary functional difference between carburetors and fuel injection is that fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure, while a carburetor relies on the vacuum created by intake air rushing through it to add the fuel to the airstream.
The fuel injector is only a nozzle and a valve: the power to inject the fuel comes from farther back in the fuel supply, from a pump or a pressure container.
The open loop fuel injection systems had already improved cylinder-to-cylinder fuel distribution and engine operation over a wide temperature range, but did not offer sufficient fuel/air mixture control to enable effective exhaust catalysis. Closed loop fuel injection systems improved the air/fuel mixture control with an exhaust gas oxygen sensor. The O2 sensor is mounted in the exhaust system upstream of the catalytic converter, and enables the engine management computer to determine and adjust the air/fuel ratio precisely and quickly.
An engine’s air/fuel ratio must be accurately controlled under all operating conditions to achieve the desired engine performance, emissions, driveability, and fuel economy. Modern electronic fuel-injection systems meter fuel very accurately and precisely, and use closed loop fuel-injection quantity-control based on feedback from an oxygen sensor (or “O2 sensor”). This enables fuel-injected engines to produce less air pollutants than comparable carbureted engines. Properly-designed fuel injection systems can react rapidly to changing inputs such as sudden throttle movements, and will control the amount of fuel injected to match the engine’s needs across a wide range of operating conditions such as engine load, ambient air temperature, engine temperature, fuel octane level, and prevailing barometric pressure.