Before we can get into a discussion about fuel mathematical function , you have to have to know a bit about electronicfuel injection(EFI ) . What ’s that ? To put it simply , it ’s acomputerized systemthat takes over where your oldcarburetorleft off , regulate the mixing of strain and fuel in yourengineto keep it running swimmingly . Too much fuel , and you ’re wasting gas . Too slight , and you could damage your engine .
For decades , fuel regulation was manage by the carburettor . In the late 1950s , car with optional electronic fuel injection came on the setting , and by the 1990s , EFI was uncouth . Today , almost all new cable car have EFI systems instead of carburetors .
The fuel map is the EFI system ’s determine for regulating the air / fuel commixture . The map has three goals:
Optimize performance– for better speed and acceleration
Optimize fuel economy– to get the bestgas gas mileage
Optimize emissions– to winnow out as many waste speck from the tailpipe as potential
Next , we ’ll represent out the part that make up this intricate computerized system .
Parts of the EFI System
sympathise fuel mapping technology is much easy if you know the soil . The centre of the whole EFI system , which control the fuel map , is the engine restraint unit ( ECU ) . Think of this component as the railroad car ’s brain . Sensors located in the engine and throughout the rest of the vehicle send info to the ECU . The ECU interprets this data and uses it to keep thecarworking at its best .
The ECU looks like a black plastic box with the electronic brains at heart . Its location diverge wildly by manufacturer . Some put the ECU in the engine compartment near thebattery , some put it near the glove box or guidance pillar in the rider compartment . Some even put it under one of the seat .
The ECU , though , is useless without its sensing element , just likeour brainswouldn’t be much good at interpreting the creation around us without our senses . While there are wads of sensors in a car that feed information to the ECU like the one that triggers that annoying " Check Engine " luminousness , we ’ll just number the ones that create the fuel map .
These are the role , but where is the map ? That ’s what we ’re going to blab out about next , so get out your graph paper .
The Fuel Map
While the automobile ’s ECU does n’t necessitate to visualize the fuel mapping , it ’s helpful for us humans to depict how this computer comes to its conclusion . You do n’t need a physical piece of graph paper , but imagining one will make it easier . The fuel map looks a lot like something you ’d learn in a third-year gamy school math class .
Imagine that piece of graphical record paper and quarter a simple cristal - Y axis on it : one line go across ( the X ) and one line rifle up and down ( the Y ) . The numbers along the 10 axis typify the engine ’s rotation per instant ( rpm ) . That ’s how tight the locomotive engine ’s interior element are turning to do whatever the driver needs – speeding up , slowing down , expect at ared lightor eventowing a gravy boat . The Y axis defend the load on the engine , or the zip required by the locomotive engine to do the job at hand .
Now imagine tip scattered all along that graph paper that represent different drive situations . That ’s the fuel function . At each point in time – and there are hundreds of possible combinations – the ECU decide what to tell the fuel injectors to do .
Pulling afifth - wheelcamperup the Rocky Mountains at main road focal ratio , for exercise , puts the railway locomotive under a Brobdingnagian burden and requires a quite a little of energy . The ECU gets input from all of the detector on fomite speed , air intake , pressure , and temperature and plot a specific point on the imaginary graphical record . The data processor is programmed to tell the fuel injectors what to do at that very point on the fuel map , and it send out the appropriate message – without any more input from the driver .
Once the ECU has received the information from the sensor and figured out what to do based on the fuel mapping , it can change three basic things to make the engine run at its best – the fuel flowing charge per unit , spark timing , and idle speed .
But what can you , the cable car owner , do to change these thing ? exchange the ECU and detector , of row . We ’ll look at improvements and troubleshooting for the fuel mapping system on the next varlet .
Changing the Fuel Map
There are essentially two case of people who ’d want to make change to the fuel map : Performance hounds and fuel misers .
Performance - minded hoi polloi who are concerned in eking every last hundredth of a moment from their cars can reprogram the ECU ’s fuel mathematical function to deliver more fuel . There may be some fuel ravage and a lot more unburned fuel in the exhaust , but that ’s the price you pay for a profits at the Saturday night retarding force races .
On the polar terminal of the scale of measurement are those drivers who are willing to sacrifice performance for fuel economy. A leaner fuel / airwave mixture is blend in to sap some power from the engine , but burn less fuel intend high miles per gallon and less fuel run off in the process . There are even adjustable MAP sensors on the mart specifically aimed at thefuel - savingcrowd .
Which brings us to one last point : You must retrieve that the information in the vehicle ’s brain is only as good as what the sensors are state it . If a sensing element is bad and sending faulty information , the ECU will not align the fuel injector correctly . unsuccessful person ordinarily come about due to a dusty sensor or a corroded or loose electrical connection . Occasionally , the sensor itself will just go forged and broadcast incorrect signals .
To stick with our earlier example of an locomotive under very grueling payload – the camper on the highway in the Rockies – let ’s suppose about what would happen if one of those sensors were unsound . If the Mass Air Flow ( MAF ) detector , for exercise , was n’t working right , it might secernate the ECU that there was n’t a lot of atmosphere move into the engine . This would move the point on the fuel mathematical function , and the ECU would n’t love to send a signal to the fuel injector to increase the amount of fuel in the mix to make up for all that atmosphere . The engine would seem sluggish , since it was n’t getting the energy it needed to do such a difficult business .
The fuel map inside the ECU is able-bodied to adjust the air / fuel mix for maximum efficiency and performance in any precondition - that is , as long as the sensors are giving it the good selective information .
