using the manufactured part enclosed transducers to control the automotive engine’s way of working

7/30/2019 USING THE MANUFACTURED PART ENCLOSED TRANSDUCERS TO CONTROL THE AUTOMOTIVE ENGINES WAY OF W

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USING THE MANUFACTURED PART ENCLOSED TRANSDUCERS

TO CONTROL THE AUTOMOTIVE ENGINES WAY OF WORKING

Univ. Prof. eng. Ion COPAE PhDMilitary Technical Academy, Bucharest, email: [email protected]

Abstract: The paper underlines the necessity of implementing specialized transducers

as components of the manufactured parts that could provide real-time information

concerning the working process of the technical processes, especially for the automobiles. It

is also underlined that modern technique and technologies provide normal working

conditions, satisfying all the inquired demands, even under the conditions of manufacturing

lack of accuracy, mounting, tuning and maintenance, due to the electronic control of the

incorporated transducers. Some examples of functional interactions are presented, using the

experimental data got during testing a car. It is also underlined the necessity of a minimal set

of transducers and executive devices that should allow a working regime within the imposed

conditions taking into account the normal wear of the system.

Keywords: automotive; fault tolerant control; engine control.

The nowadays technical systems are featured by a high structural complexity, due to

the necessity to satisfy some every moment more severe demands. Therefore a higher

functional complexity appears, due to the fact the system is controllable and observable. Asseen in fig. 1, the assembly made of the system and the controller is featured by internal

amounts, outside variables, commands and amounts that ensure a real time diagnose. To

fulfill these requests, the system is equipped with transducers and executive devices as shown

in fig. 2, that assure among others, a model-based diagnose [1].

Fig. 1 Electronically controlled system

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Fig. 2 Electronically controlled system

To the present, up-to-date, electronically controlled systems, the real-time diagnose

became a very important issue, hence the built-in transducers role considerably increased.

These solutions assure the systems work even in faulty conditions. For this reason, this kind

of solution was named as fault tolerant control (FTC) and its flowchart is depicted in fig. 3.

Fig. 3 Fault Tolerant Control (FTC)

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Should be said that, as the electronic control accepts the term, the fault means a

deviation of the monitored amount from its known (enforced) nominal value (when lack of

malfunction). As seen in fig. 3, the diagnose process of the system is placed before the

control. Therefore, the on-board computer issues control commands and based on the

diagnose process accordingly. Also, fig. 3 shows that FTC operates in the presence of some

of the systems components faults, at its executive devices and built-in transducers as well.Among the complex technical systems, the electronically controlled working process

of a passenger car is a good example. To the present, up-to-date solutions, the electronic

control works not only for the engine but for other elements such as the suspension,

transmission, steering system, braking system, traction and so on. Such a control can be seen

in fig. 4.

Fig. 4 FTC strategy for Buick Le Sabre passenger car

The gasoline injection engine has a lot of built-in transducers as well as executive

devices that assure the working control and the diagnose process. As an example, fig. 5 and 6

depict the time histories of the mentioned amounts for an OPEL Vectra B passenger car [2].

Fig. 5 Experimental results

To locate the faults, several identification procedures are available. For instance, to

locate a fault, a time-frequency analysis using the Stockwell Transform of the data providedby the on-board computer can be performed as seen in fig. 7b.

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Fig. 7 presents the case of the intended fault of the lambda transducer on B areas.

From the chart one could notice the presence of different spectral images on the areas A, C

andD where the transducer worked.

Fig. 6 Experimental results

Fig. 7 Time-frequency analysis

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When model-based diagnose involved, the detection of the faults is based on the

generating the residual, as seen in fig. 4. In the simplest case the residual represents the

difference between the checked experimental amount and the one obtained from the

mathematical model that was established on the basis of the data provided by the on-board

computer [3, 4].

As resulted from fig. 8, generating the residual r(t) requests the transfer function GandHwritten in Laplace images, as well as equations (1) and (2). The scheme contains the

command amount u(t) the tuned amounty(t) and the faultf(t). If fault exists, then the residual

was not zero and so was its transfer function, as resulting from expression (3).

Fig. 8 Generating the residual

Since the on-board computer provides the values of the monitored amounts one couldset the mathematical model and the fault detection based on these data [5]. For example, the

mathematical model of the working process when lack of faults is considered, as known from

all the references is given as:

( ) ( ) ( )

( ) ( ) ( )

x t Ax t Bu t

y t Cx t Du t

(4)

and the working process when faults occur is given by the differential equations system:

( )( ) ( ) ( ) ( )

( ) ( ) ( )) (

a

s

x t A x t B u t

y t Cx t Du t

A

f t

f t

)

(5)

In the equations of system (5), which give a mathematical algorithm in the continuous

domain, the components faults A, actuators faultsfa(t) and transducers faultsfs(t) have been

considered as additional type ones.

In the same manner, the mathematical algorithm within the discrete domain is given

by:

( 1) ( ) ( ) (

( ) ( ) ( )

a

s s a

x k A x k B u

y k Cx k D u

A S

S S S t

k(6)

where Sa and Ss represents the matrices of the actuators and transducers faults, settled by:

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k diag{ } , 1... ; diag{ } , 1... ;0 1; 0 1i k ia a s a a aS s i m S s k p s s (7)

considering m actuators and p transducers.

If, for instance sa2=0.9 and ss

3=0.8, this means the executive device no. 2 (indicated)

has a 10% failure while transducer 3 (known) has a 20% failure.

Fig. 9 depicts the apparition of a fault at the air bulk transducer that can be seen bothin the dynamic serial of the air consumption per hour (fig. 9a) and by applying the Stockwell

Transform (fig. 9d).

Fig. 9 Fault detection

Eventually, should be mentioned that the minimal number of necessary transducers

results from the conditions that define the analytical redundancy.

References:1. Nyberg M.Model Based Fault Diagnosis. Methods, Theory and Automotive Engine

Applications. Thesis, Linkoping, Sweden, 1999

2. Copae I. Car Dynamics. Theory and Experimental Research, Military Technical

Academy, Bucharest, 2003

3. Frisk E. Model-based Fault Diagnosis applied to an SI Engine. Master Thesis,

Linkoping, Sweden, 1996

4. Frisk E. Residual Generation for Fault Diagnosis: Nominal and Robust Design.

Dissertation, Linkoping, Sweden, 1998

5. Kanev S. Simultaneous Sensor and Actuator Fault Isolation Given Input/Output

Data. University of Twente, Twente, Netherlands, http://www.sce.tn.utwente.nl, 2001

using the manufactured part enclosed transducers to control the automotive engine’s way of working

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