In the maintenance of the vehicles, there has to be a presented knowledge of all the filters that are related with the operation of the car, especially those that work directly with the engine. Have said this, in Ecuador, one of the filters that the users of cars less have present when it makes maintenance of the same, is the filter of air. In the present article it will give knowledge which is the effects of an obstruction of air in the admission. The obstruction in the filters of air gives by the accumulation of dirt and impurities that there is in the air, especially in the roads of ballast that still are many in the Ecuador. The effect that has this tamponade of the filter sees reflected directly with the voltage of the signal that issues the sensor MAP to the ECU, and this relates over time of injection and therefore the power in the wheels, the broadcasts of gases, temperature of operation, etc. Although it exists sensors and actuators for example the sensor of oxygen, that treat to correct this bad operation in the entrance of air balancing mixes it air-fuel until it arrive to a mix stoichiometry, however if the damage reaches 25%, 50% or 75% that they are the values of obstruction that used for this investigation, the operation of the car sees affected in his whole until that point.

For the development of the project where looks for analyses the power and broadcasts of gases by means of the variation of the entrance of air to the manifold of admission simulating an obturation to the filter of air, makes the proofs to 3 different diets of twist, to 2000 rpm, 3000 rpm and 4000 rpm.

In all the proofs in normal conditions of operation of the engine the temperature of work is of 90 ± 5°C this saw affected directly when they made the proofs with the obstruction of the entrance of air. The petrol used in the proofs is the same stops of this form avoid that it produce errors of measurement during the proof.

Characteristics of the vehicle

In the Table 1 presents the characteristics of the vehicle..

Table 1: Characteristics of the vehicle.

Method for the taking of data

To obtain the data, situated to the vehicle in the bank dynamometric for of this form measure the power that delivers to the wheels, to simulate the obturation of the filter of air what did is to cover a determinate area the entrance of air to the manifold of admission, the restriction of to entrance of air is of 25%, 50% and 75%. Also to the same instant the voltage of the signal of the MAP was being watched with a scanner in group with an analyzer of gases that served for the obtaining of the gases issued in the different RPM that made the proofs.

As already it mentioned the data were obtained with proofs to different RPM and with different obstruction of air. It obtained power in the wheels, broadcast of gases, and variation of voltage of the signal of the MAP (Figures 1-3). With the same method made all the following proofs for the different RPM and for the percentages of obstruction (Table 2).

Table 2: Data obtained without variations.

Figure 1: Data of scanner.

Figure 2: Data of bankdynamometer.

Figure 3: Data of analyzer of gases.

In the previous table see the data obtained that work like reference, that is to say the data that obtained without modifications of car, fits to mention that the car and all his elements were in excellent conditions of operation (Table 3).

Table 3: Data with modification in the entrance of air.

Verification of the data

With the help of the program Minitap makes regressions for each one of the groups of data that obtained to verify that it do not exist an error in the tabulation of all they. In the inferior part appreciates the Figures 4-7, where has to the R square is of 81.54% guaranteeing that it has a good adjust of the curve regarding the points measured.

Figure 4: Regression for data of CO.

Figure 5: Regression for data of HC.

Figure 6: Regression for data of Power.

Figure 7: Regression for data of the signal of the MAP.

Also we have in the following Figure 4, which can see that the points taken find distributed between the two sides of zero, besides do not find red points that indicate that there are data taken wrongly. This made for the data that considered more important for the analysis.

Table 4: Half Values obtained.

With the help of the program Minitap made charts of boxes for the group of data of the HC, CO, signal of MAP, and power. To continuation observes the behaviors of these parameters of operation of the engine, that is to say the effect that causes an obstruction in the filter of air.

Behavior of the power and hydrocarbons

It analyses these two parameters of operation since the HC are dependent of a lot of variables like the rpm, lambda, and wear of the engine, among others.

In the Figure 8 has in function of the percentages in passing of the air to the manifold of admission, the powers and HC. It observes that while it exists the maximum percentage in passing of air has a notorious heaves of power in the engine and low broadcasts of HC, in body percentage all the elements of vehicle act so that of maximum power without pollution which is what look for all the manufacturers of cars. While the low percentage notices one heaves in the HC that stabilizes after tamponed 25% of the entrance and has a drop in the power that increases while it increases the obstruction, what can deduce that the elements of the engine look for primarily not contaminating with these gases sacrificing the power.

Figure 8: Relation opening percentage-Power-HC.

In the Figure 9 has the relation between the rpm, power and HC, exists a heave big of power of 2000 to 3000 rpm but does not give of the same size of 3000 to 4000 and exists a drop of HC of 2000 to 3000 and one heaves of 3000 to 4000, although there is more power to 4000 rpm also goes to contaminate a bit more since it limits him the volume of air which results in a rich mix and therefore they did not burn these hydrocarbons by a fault of oxygen.

Figure 9: Relation RPM-Power-HC.

Behavior of the signal of the MAP

The signal of the MAP is critical for the determination of the time of injection since if east issues a greater voltage the ECU understands that it has to supply greater fuel, increasing the time of injection.

If it has an obstruction in the step of the air, the signal of the MAP varied as it can observe in the Figure 10. If it varies the percentage of obstruction of the step of air observes that it exists a fall of voltage while this diminishes and if the RPM go up also goes up the voltage of the signal, of this can notice that to some extent the ECU treats to compensate the reading of this signal, however once that there is not as only it does a reference of the voltage given with the RPM and simply short the injection and loses power notoriously.

Figure 10: Relation signal of the MAP-RPM-percentage.

Behavior of CO and CO₂

Generally of these two gases the most harmful is the CO since this can cause give us irremediable instantaneous to living beings.

When the car this in optimum conditions observed in the Figure 11 that has a high percentage of CO₂ and low of CO which is those that looks for in a good operation, while the percentage in passing of the low air has a small decrease of CO₂ and a brief heaves of CO, but are so low the percentages that are not considered critics, which can conclude that these two parameters do not depend directly of a to obstruction in the pipe of admission (Table 4).

Figure 11: Relation Percentage-CO-CO₂.

Has to have a lot of care in the maintenance of the filter of air, since it checked that while it exist a greater obstruction to the step of the air exist harmful effects in the HC in power and in signal of the MAP.

It has clear that in operation in the real life a car is almost impossible that obstruct 75% in passing of the air, since this as it saw previously diminishes the power of the vehicle until in 28%, which gave a notorious effect in the driving, and of course the temperature of operation would see affected instantly what can result in a melted or crack of the engine.

It was necessary an investigation to determine the percentage of heaves that has in consumption of fuel a car that have a tamponade in the entrance of air, that is to say in the filter of air since if the power sees affected goes to need accelerate more to break the factors of resistance to the rolling of the vehicle.