Mapping and e-injection, three-dimensional lifespan

Carburizing machine, how does it work?

dosage

Dosing accuracy is the strength of the injection and what sets it apart from a carburetor. Indeed, it takes about 14,5 grams of air to burn one gram of gasoline, because unlike diesel fuel, a gasoline engine runs at constant wealth. This means that when the air flow increases or decreases, the gasoline flow must be adapted. Otherwise, the flammability conditions are not met and the spark plug will not ignite the mixture. Moreover, for the combustion to be complete, which reduces the emission of pollutants, it is necessary to remain very close to the proportion we have indicated. This is even more true of catalytic treatment, which only works in a very narrow range of richness, impossible to maintain with a carburetor, otherwise ineffective. All these reasons explain the disappearance of the carburetor in favor of the injection.

Open or closed loop?

Expressing the mass ratio of air / gasoline is hardly impressive, but if we consider that we have gas, on the one hand, liquid, on the other, and what we say by volume, then we find that we need 10 liters of air to burn liter of gasoline! In everyday life, this explains the importance of a clean air filter, which easily sees 000 liters of air passing through it to burn a full tank! But the air density is not constant. It varies when it is hot or cold, humid or dry, or when you are at altitude or sea level. To accommodate these differences, sensors are used that convert information into electrical signals ranging from 100 to 000 volts. This applies to air temperature, but also to coolant temperature, atmospheric pressure, or in the air box, etc. The sensors are also designed to communicate the pilot's needs, which he expresses through the accelerator handle. This role has been transferred to the famous TPS "(Throttle Position Sensor" or Moliere's butterfly position sensor).

Indeed, most injections today operate according to the "α / N" strategy, α is the butterfly opening angle and N is the engine speed. Thus, in every situation, the computer has in memory the amount of fuel that it must inject. It is this memory that is called mapping or mapping. The more powerful the computer, the more points it has in mapping and the more it is able to finely adapt to various situations (pressure, temperature fluctuations, etc.). Indeed, there is not one, but maps that register the injection time in accordance with the α / N parameters for engine temperature X, air temperature Y and pressure Z. Each time the parameter is changed, a new comparison or at least corrections must be established.

Under close supervision.

To ensure optimum carburation and within a range compatible with catalyst operation, lambda probes measure the oxygen level in the exhaust gas. If there is too much oxygen, it means that the mixture is too lean, and in fact the calculator should enrich the mixture. If there is no more oxygen, the mixture is too rich and the calculator is depleted. This post-run control system is called "closed loop". On heavily decontaminated (car) engines, we even check the correct functioning of the catalyst using a lambda probe at the inlet and another at the outlet, a kind of loop in the loop. But under certain conditions, the information about the probe is not used. Thus, cold, when the catalyst is not yet working and the mixture must be enriched in order to compensate for the condensation of gasoline on the cold walls of the engine, we are freed from lambda probes. Efforts are being made as part of emission control standards to minimize this transition period and even heat the probes with the built-in electrical resistance so that they respond faster and not slow down. But it is when driving at high loads (green gases) that you enter the "open loop", forgetting about the lambda probes. Indeed, under these conditions, which are beyond the control of standardized tests, both performance and engine retention are sought. In fact, the air / gasoline ratio is no longer 14,5 / 1, but rather drops to around 13/1. We enrich ourselves to win horses and also to cool the engine because we know that bad mixtures heat up the engines and risk damaging them. So when you drive fast, you consume more, but you also pollute more from a quality point of view.

Injectors and mechanics

For everything to work, it is not enough to have sensors and a calculator ... It also requires gasoline! Better than that, you need pressurized gasoline. Thus, the injection engine acquires an electric petrol pump, usually housed in a tank, with a calibration system. He supplies the injectors with fuel. They consist of a needle (needle) surrounded by an electric coil. As the calculator feeds the coil, the needle is lifted by the magnetic field, releasing pressurized gasoline, which is sprayed into the manifold. Indeed, on our bikes we use "indirect" injection into the manifold or air box. The car uses "direct" injection, where fuel is injected at a higher pressure into the combustion chamber. This reduces fuel consumption, but any medal has its drawback, direct injection succeeds in getting fine particles out into the gasoline engine. So as far as we can, let's continue with our good indirect injection. Moreover, the system can be improved, as demonstrated by our recent topic on OFF ON ...

Better but harder

Injectors, sensors, control units, gas pump, probes, injections make our motorcycles more expensive and heavier. But it also opens up many possibilities for us. In addition, we are talking about injections, but note that all of this is also combined with ignition, the progress of which also varies depending on the display associated with the injection.

Motorcycle performance is increasing, consumption is decreasing. No more tuning, bikes that do not support the mountain, etc. From now on everything is controlled automatically, without the intervention of the pilot or mechanic. This is a good thing, one might say, because you can no longer touch anything, or almost anything, without adequate electronic equipment. But above all, injection opens new doors for us, in particular the arrival of traction control. Modulating engine power is now child's play. Ask general practitioner drivers what they think and if they think “it was better before” !!