**4. Sensor design**

A good sensitivity of the temperature and vibration of the combustion motor surface depends of the internal membranes of the designed smart sensor, which are prepared by nanotructures of AAO, hence the elaboration of the nanostructures (nanoholes and nanotubes) are prepared by a sequence of steps over aluminum: ultrasound cleaning of aluminum, electropolishing, anodization, and atomic load deposition. Nevertheless, if there is not a good quality of aluminum, the base of the nanostructure could not have robustness over their geometry, in **Figure 10** is showed some aluminum samples at 99.9 percent for the designed vibration sensor [13]. Sensors based in samples of nanostructures give the possibility to achieve robustness and short response time [14].

**Figure 10.** *Aluminum samples.*

*Perspective Chapter: Optimal Analysis for the Correlation between Vibration and Temperature… DOI: http://dx.doi.org/10.5772/intechopen.107622*

#### **Figure 11.** *Electropolishing.*

Electropolishing is an electrochemical process according to achieve more sophisticated cleaning over every sample by electrolysis and from anode to cathode [13], that is showed by **Figure 11**.

After the electropolishing, the samples achieve very much shining like a mirror whereby **Figure 12** shows 4 samples, in which one of them (up left side) is showed the best electropolished sample.

The anodization produces chemical effects on the cleaned aluminum such as the holes in nanoscales, this process was made in controlled electro-chemical perchloric acid reaction, and adjusting the electrical source between 20 V to 30 V in environment around 0 Celsius degrees, which is showed by **Figure 13**. Moreover, by electrochemical deposition was possible to prepare nanostructures amorphous over the AAO samples.

As a result were obtained nanostructures samples based in AAO, which are showed by **Figure 14**. The subfigures "A" and "C" are the samples prepared in the Applied Nanophysics, Institute for Physics of TU Ilmenau by the cooperation research between PUCP and TU Ilmenau, "B" is the sample prepared in the researching

**Figure 12.** *Electropolished samples.*

**Figure 13.** *Anodization and electrochemical deposition process for the sensor elaboration.*

**Figure 14.** *AAO samples for the sensor design.*

laboratories 1 and 2 of the Mechanical Department of PUCP by the optimal procedure discovered by Prof. Lei group.

The samples prepared are adapted through its own geometry in nanoscale due to obtain amorphous nanotubes for the vibration sensor and amorphous nanoholes for the temperature sensor. There is an IR emitter as part of the sensor/transducer design, which send IR signal to the combustion motor surface in controlled frequency due to recognize the differences with the IR signal caused by the temperature changes of the combustion motor surface. Therefore, the temperature measurement is correlated between the IR signal with its own IR signal caused because of the temperature changes in the motor surface (temperature measured by IR [6]).

The receptors are given by the nanostructures samples that send the measured data (temperature and vibration) to the microcontroller owing to execute the mathematical model of the correlation among the theoretical model with the experimental mathematical analysis, finally that data is sent to the user by wireless port. In order to obtain the electrical response of the measured variable, it was fixed some cables in every corner of the sample. The electrical resistance equivalent is the physical variable to correlate the measured variable. In **Figure 15** are showed 3 prototypes of designed sensors/transducers (A, B and C).

*Perspective Chapter: Optimal Analysis for the Correlation between Vibration and Temperature… DOI: http://dx.doi.org/10.5772/intechopen.107622*

**Figure 15.** *Prototypes of proposed sensors/transducers.*

The sample B of **Figure 12** is showed under a microscope Litz in the scale 25 micrometers, thereby the **Figure 16** shows some amorphous structures with maximal scales are around 1000 nanometers.

In **Figure 17** is depicted the algorithm scheme for the sensor transduction by the flowchart of the sensor/transducer operation described in paragraphs above, in which physical variables temperature and vibration are measured and processed by concurrence and finally both signals are correlated according to obtain the final transduction result.

Algorithm scheme in operation during the measurement of the physical variables vibration and temperature of motor surfaces is depicted in the following **Figure 18**, thereby the predictions of the adaptive algorithm can be obtained by the interpretation of the IR reception [6].

In the following **Figure 19**, by the curve A is depicted the measurement data from the designed sensor, the curve B represents the measurement data received by the personal computer at 50 meters of distance with a delay L1 because of the medium used was internet. Nevertheless, if it is used radiofrequency medium communication the delay is reduced in L2 as it is depicted by the curve C.

It is showed by the **Figure 20** the motor used for the experiments, which is a Nissan frontier 2005. The sensors (4 of them) were positioned around the motor by non-contact in every Cartesian axis (X, Y, Z).

**Figure 17.** *Algorithm scheme for the sensor transduction.*

#### **Figure 18.**

*Algorithm scheme in operation during the measurement.*

*Representation of the measured data (a), its transmission by internet (B) and by radiofrequency (C).*

*Perspective Chapter: Optimal Analysis for the Correlation between Vibration and Temperature… DOI: http://dx.doi.org/10.5772/intechopen.107622*

**Figure 20.** *Combustion motor of a Nissan frontier 2005, in which were made the experiments.*

Fixing a small electro-pneumatic actuator over the accelerator pedal, which receive the control signal according the main control algorithm that receive the vibration and temperature signal from the designed sensor (through the radiofrequency antennas).

In **Figure 21** is showed the vibration of the combustion motor measured by the designed sensor. The vibration signal was transduced from IR to electrical signal (Voltage) that is showed by the blue color curve, and its amplification in equivalent of Decibels by the red color curve in the **Figure 18**. The combustion motor was evaluated in operation around 4000 RPM and the maximal spectral density was obtained approximately in 68 Hz that can be seen by the green color curve, which in addition can justify the operation frequency of the internal combustion motor.

The vibration of the motor surface was captured by the designed sensor/transducer and it was sent by IR to the emitter antenna that sent the data by radiofrequency to the receptor antenna, which is at 50 meters outside, moreover the receptor antenna sent

**Figure 21.** *Vibration curves achieved by the designed sensor.*

the measured vibration to a personal computer by IR, also, according the control signal to activate the electro-pneumatic actuator to change the position of the accelerator pedal. That curves information can be interpreted by the user according to get understanding of the behavior of the motor as a consequence of the combustion. It is necessary to remind that the intelligent algorithm of the adaptive correlation to achieve the physical variables transductions had 87 SNR (Signal to Noise Ratio) in average.

The operating frequency is quite dependent of the vibration frequency of the combustion motor, because of this is the main source of changes in the described system. The vibration measurement can be simpler due to its correlation with the vibrating motor, however, the temperature measurement depends not only from the operating vibration motor, it also depends from its delay caused due to the thermal inertia. Furthermore, the sample frequency is part of the designed sensor analysis.

It was evaluated the performance of the sensor/transducer by different temperature changes, which were caused by accelerating the motor during 45 minutes approximately. **Figure 22** shows the optimal estimated temperature of the surface motor that is given by the green color curve. The optimal estimation is achieved as a consequence of the correlation between the experimental measurement (blue color curve) with the temperature measurement by a thermocouple type k (red color curve). Hence, the designed sensor/transducer can measure the temperature of the motor surface by optimal estimations according to answer in front of disturbances, moreover the measured data was sent through IR to the emitter antenna that sent the data to the receptor antenna by radiofrequency at 50 meters outside, from which the information is received by a personal computer through IR with the receptor antenna. The user can interpret the data received, such as for example the diagnostic of the motor by the combustion effects because of the temperature changes. The delay obtained by the radiofrequency data monitoring (vibration and temperature of the surface motor) was between 700mS to 800mS, and the delay obtained by internet data monitoring was between 1.2S to 1.4S.

**Figure 22.** *Temperature curve from the designed sensor in Celsius degrees.*

*Perspective Chapter: Optimal Analysis for the Correlation between Vibration and Temperature… DOI: http://dx.doi.org/10.5772/intechopen.107622*
