**1. Introduction**

32 Fuel Injection in Automotive Engineering

Teng Zhang. & Dian Tang. (2009). *Current Research Status of Corrosion Resistant Coatings*,

Tsukahara.M. & Yoshimoto, Y. (1992). *Reduction of NOx, Smoke, BSFC, and Maximum* 

Tsukahara.M.; Murayama.T. & Yoshimoto. Y. (1982). *Influence of Fuel Properties on the* 

Wagner U.; Eckert P. & Spicher U. (2008). *Possibilities of Simultaneous In–cylinder Reduction of* 

*Combustion Pressure by Low compression ratios in a Diesel Engine Fueled by Emulsified* 

*Combustion in Diesel Engine Driven by the Emulsified Fuel,* Journal of the JSME, 1982,

*Soot and NOx Emissions for Diesel Engines with Direct Injection*. International Journal

2009, Recent Patents on Corrosion Science*,* 2009, *1,* 1-5.

of Rotating Machinery – Vol No: 2008: Article ID: 175956.

*fuel*. SAE Technical Paper No: 92046.

Vol. 25, No: 202, pp. 612 – 619.

This chapter aims to present an alternative to quality control of the viscosity of two important fuels in the international scenery - aviation kerosene and diesel oil – by statistical multivariate modeling (Pasadakis et al., 2006).

Viscosity is one of the most important properties of fuels; it influences the circulation and the fuel injection in the operation of injection engines. Engines efficiency in the combustion process depends on this property.

Out of specification values can decrease the fuel volatilization, thus implying, in an incomplete combustion (Pontes et al., 2010). This physicochemical property can vary significantly with the modification of the cast during the processing of crude in a refinery (Figure 1), maintaining the same conditions of production control, which compromises the quality standards. This leads to the need to determine the viscosity or provide it as often as possible in lieu of performing the traditional point analysis in the laboratory that can take long time.

According to Dave et al. (2003), the use of field instruments in conjunction with statistical multivariate techniques to determine, in real-time, properties of the products is one way to optimize the operations of oil refining.

Each refinery has at least one primary distillation tower, where the components of crude oil are separated into different sections using different boiling points, and different arrangements of unit conversion. In general, the refining margin increases with the complexity of the refinery. Decisions about how to operate and monitor a refinery and how to build the units, are factors that provide competitive advantages to oil companies.

The hydrotreatment is a catalytic process that removes large amounts of sulfur and nitrogen from the distillation fractions (Fernández et al., 1995). The fluidized catalytic cracking (FCC) is a process widely used in a petroleum refining industry. It consists in cracking large molecules into smaller ones by high temperatures. Thus, heavy oils are converted into products with

Multivariate Modeling in Quality Control of Viscosity in Fuel: An Application in Oil Industry 35

Fig. 2. Combustor and engine - schema (Gomez et al., 2007).

Finally, in Section 5, the conclusions reached are discussed.

consumption.

Kinematic viscosity of this product is an important property in terms of its effect on power systems and in fuel injection. Both high and low viscosities are undesirable since they can cause, among others, problems of fuel atomization. The formation of large and small droplets (low viscosity), can lead to a poor distribution of fuel and compromise the mixture air - fuel resulting in an incomplete combustion followed by loss of power and greater fuel

In Section 2, it will be presented a method for acquiring and construct the database. In Section 3, theoretical foundations of the statistical multivariate methods used. In Section 4, are presented the method application and the results for a real process of production.

higher added value (IEA, n.d.). In addition, some refineries have used the coking unit to maximize the refining margin in the conversion of waste from distillation towers.

Fig. 1. Simplified process flow diagram of a refinery (Park et al., 2010)

Important products of refineries are the fuels for several kinds of existing engines. This way, fuel for jets is derived from petroleum and it is suitable for power generation by combustion in gas turbine engines for aircraft (see Fig.2). Jet fuel is produced by fractionation of petroleum by distillation at atmospheric pressure, with boiling range between 150 and 300 ° C, followed by finishes and treatments that aim primarily eliminate the undesirable effects of sulfur compounds, nitrogen and oxygen.

The viscosity of kerosene is limited to a maximum value to obtain a minimum loss of pressure in the flow at low temperature, as well as to allow using adequate spray nozzles for the fuel in order to improve the conditions of combustion. The viscosity property can significantly affect the lubricity of the fuel property, and, consequently, the life of the aircraft fuel pump.

The diesel fuel is a derivative of petroleum used in internal combustion engines compression to move motor vehicles (Fig. 3). It can also be used in marine engines and as a fuel for home heating. It is composed mainly of paraffinic hydrocarbons, and it is not desirable to the presence of olefins and aromatics. Its normal boiling range is 100 to 390 º C, while the number of carbon atoms should be located between six and eighteen atoms.

The chemical composition of diesel oil directly affects its performance and is related to the type of oil used and with the adopted processes for their production in refineries.

Overall this product is composed of one or more cuts from the distillation of petroleum, and it can be added to other current refining processes, for example, the product obtained from catalytic cracking called light oil recycled.

higher added value (IEA, n.d.). In addition, some refineries have used the coking unit to

maximize the refining margin in the conversion of waste from distillation towers.

Fig. 1. Simplified process flow diagram of a refinery (Park et al., 2010)

of sulfur compounds, nitrogen and oxygen.

catalytic cracking called light oil recycled.

Important products of refineries are the fuels for several kinds of existing engines. This way, fuel for jets is derived from petroleum and it is suitable for power generation by combustion in gas turbine engines for aircraft (see Fig.2). Jet fuel is produced by fractionation of petroleum by distillation at atmospheric pressure, with boiling range between 150 and 300 ° C, followed by finishes and treatments that aim primarily eliminate the undesirable effects

The viscosity of kerosene is limited to a maximum value to obtain a minimum loss of pressure in the flow at low temperature, as well as to allow using adequate spray nozzles for the fuel in order to improve the conditions of combustion. The viscosity property can significantly affect

The diesel fuel is a derivative of petroleum used in internal combustion engines compression to move motor vehicles (Fig. 3). It can also be used in marine engines and as a fuel for home heating. It is composed mainly of paraffinic hydrocarbons, and it is not desirable to the presence of olefins and aromatics. Its normal boiling range is 100 to 390 º C, while the number of carbon atoms should be located between six and eighteen atoms.

The chemical composition of diesel oil directly affects its performance and is related to the

Overall this product is composed of one or more cuts from the distillation of petroleum, and it can be added to other current refining processes, for example, the product obtained from

the lubricity of the fuel property, and, consequently, the life of the aircraft fuel pump.

type of oil used and with the adopted processes for their production in refineries.

Fig. 2. Combustor and engine - schema (Gomez et al., 2007).

Kinematic viscosity of this product is an important property in terms of its effect on power systems and in fuel injection. Both high and low viscosities are undesirable since they can cause, among others, problems of fuel atomization. The formation of large and small droplets (low viscosity), can lead to a poor distribution of fuel and compromise the mixture air - fuel resulting in an incomplete combustion followed by loss of power and greater fuel consumption.

In Section 2, it will be presented a method for acquiring and construct the database. In Section 3, theoretical foundations of the statistical multivariate methods used. In Section 4, are presented the method application and the results for a real process of production. Finally, in Section 5, the conclusions reached are discussed.

Multivariate Modeling in Quality Control of Viscosity in Fuel: An Application in Oil Industry 37

Fig. 4. "Wishbone" interferometric system employed in modern NIR spectrophotometers based on Fourier Transform. A, beam splitter; B, corner cubic mirrors; C, anchor, and D,

An interferogram is obtained as a result of a graph of the signal intensity received by the detector versus the difference in optical path traveled by the beams. Then, like the Fourier Transform translates the recurring phenomenon in a series of sines and cosines (see Fig. 5), it is possible to transform the interferogram in a spectrum transmittance. The amount of radiation absorbed is determined by using the co-logarithm of the transmittance spectrum.

Fig. 5. Interferogram of radiation containing several wavelengths (adapted from Smith, 2011)

The characterization of the mathematical models more adequate was performed by using the multivariate technique with partial least squares regression (PLS). This is an analysis technique where the original matrix of data is represented by factors or latent variables. Only the portion of the spectral data that correlates with the property assessed is included in this representation. The first factor, calculated by a statistical program The Unscrambler®, has the highest correlation of spectral data with respect the property of interest. The residual spectrum,

"wishbone" (Pasquini, 2003)

**3. Multivariate analysis** 

Fig. 3. Diesel engine (Marshall, 2002)
