Automotive Engineering – Design, Manufacture and Development [303953]

[anonimizat], Manufacture and Development

Dissertation Thesis

Coordinator:

Assoc. Dr. Phd. Sorin Dumitru

Student: [anonimizat], 2017

[anonimizat], Manufacture and Development

ENGINE COLD TESTING

Coordinator:

Assoc. Dr. Phd. Sorin Dumitru

Student: [anonimizat], 2017

CONTENTS

CHAPTER 1 – COLD TESTING OF IC ENGINES

1.1. Introduction………………………………………………………………………….

1.2. Evolution of the equipment through time…………………………………………….

CHAPTER 2 – COLD TESTING MACHINES

2.1. Cold tester by HIRATA…………………………………………………………….

2.2. Shanghai W-Ibeda High Tech. [anonimizat]………………

CHAPTER 3 – ACTUAL STATE OF THE SYSTEM

3.1. General overview……………………………………………………………………

3.2. Tested part details…………………………………………………………………..

3.3. Machine systems……………………………………………………………………

3.3.1. Pneumatic system…………………………………………………………

3.3.2. Electrical system………………………………………………………….

3.3.3. Guarding system………………………………………………………….

3.4. Machine control…………………………………………………………………….

3.4.1. HMI screen……………………………………………………………….

3.4.2. Control console push buttons…………………………………………….

3.4.3. Infeed side push buttons……………………………………………….…

3.5. Cycle overview…………………………………………………………………….

3.6. Part testing overview…………………………………………………………………

CHAPTER 4 – ENGINE TESTING

4.1. Test sequence……………………………………………………………………..

4.1.1. Static test………………………………………………………………..

4.1.2. High Speed Test [1000 ROM] ……………………………………..….

4.1.3. Noise & Vibration Test [1000 RPM] ……………………………….…

4.1.4. Low Speed Test [120 RPM] ……………………………………….…..

4.1.5. Oil Pressure Switch Function Test [45 RPM] …………………………

4.2. Implemented improvements

4.2.1. OPS verification on static, 1000rpm, 45rpm……………………………

4.2.2. MTS verification on static and 1000 rpm……………………………….

4.4.3. Knock sensor signal analysis……………………………………………

CONCLUSIONS………………………………………………………………………………

REFERENCES…………………………………………………………………………..……

CHAPTER 1 – COLD TESTING OF IC ENGINES

1.1 Introduction

Cold Testing

Cold Testing is a checking procedure placed at the end of main Assembly Line to check the Engine build without actually firing the Engine. This will not allow any assembly defect to pass down the testing line. [anonimizat]’s (IPV) at critical assembly operations to ensure inbuilt quality and early detection of defects are used.

The purpose is to detect the defects and mechanical integrity after assembly in Dynamic Cold condition.

The engine is fixed automatically and a variable speed drive at various speeds spins the crank shaft. A computer obtains high speed analog data from pressure and torque transducers placed on the machine.

Figure 1.1 – Cold Test Cell of IC Engines

Data is also gathered from crank and cam sensors placed on the engine. The gathered data is examined using special algorithms and limits are used to the results calculated from the waveforms to find out the accept/reject status. The time of cycle is 3 [anonimizat]. [anonimizat].

The drive adaptors are fitted at earlier station and removed after Cold test station. Engine is transferred to Cold Test Bench. [anonimizat]d Engine is rotated with external device. The typical power required to drive a cold test bed is approximately 20 KW.

Figure 1.2 – Cold Test Cell of IC Engines

Following tests and measurements are carried out:

Breakaway and Running Torque measurement to check the mechanical integrity of Crank mechanism and valve train.

Exhaust Manifold pressure build up and Intake Manifold depression measurement to check Combustion chamber defects.

Oil Pressure and Oil temperature measurements to check Oil circuit defects.

Common Rail system check.

Noise and Vibration check (NVH)

Electrical connection and sensors response.

1.2 Evolution of the equipment through time

In 1944, RAMSAY [1] published in his paper named “Means for testing the ignition systems of internal combustion engines employing spark ignition”, an equipment that test the integrity of the ingnition system of a internal combustion engine.

This was one of the earliest equipment for testing the engine in a cold state, in this case, the ignition system.

Figure 1.3 – The circuit diagram of an ignition

testing apparatus constructed in accordance with

the invention applied to a coil ignition system, Ramsay,1944

The present applicant's relates to such apparatus and describes arrangements connected preferably to the primary winding of the ignition apparatus and including a telephone receiver or other high speed indicating device arranged to receive impulses and give indications corresponding to the impulses delivered to the sparking plugs. Such an arrangement enables a user to determine rapidly and easily whether any of the sparking plugs are faulty without having access to any of the screened leads.

Preferably, means such as a variable resistance is provided for progressively reducing the intensity of the impulses delivered to the sparking plugs so that it is possible not only to tell whether any plug is failing to function but also to gain some idea of the state of 'the plug. and what likelihood there is of their failing shortly.

Such apparatus, however, does not indicate which sparking plug is faulty or likely to become faulty and one object of the present invention is to provide testing equipment which not only indicates whether or not certain plugs are faulty. or likely to become so, but also identifies which are the plugs in question.

To this end according to the present invention apparatus for testing ignition systems of internal combustion engines includes an oscillograph. means for connecting the oscillograph to the ignition apparatus so as to receive impulses and give indications corresponding to the impulses delivered to the sparking plugs, and means for synchronizing the time base of the oscillograph with the cycle of the engine.

For example the time base of the oscillograph may be triggered from an identifiable point in the cycle of the engine.

In 1984, Mudge et al. [2] in his paper named ”Engine Cold Testing”, presented an equipment for cold testing of typical piston engines to determine their internal integrity and tolerance prior to further testing or use which could be destructive if a defect exists.

In order to cold testing a internal combustion engine, a source of pressure oil is fed to the normal engine oil pressure system while the engine is slowly rotated. The amount of oil flow is measured and recorded by a unique orifice flow device which yields a differential pressure signal in proportion to the oil flow as the engine is rotated.

The variation in oil flow in selected segments of rotation is analyzed to determine the engine condition.

Common assembly faults that can be detected and isolated for repair:

missing rod

missing main bearings

loose bearing caps

excessive bearing clearance.

Fig.1.4 – Engine oil signature analysis system

For this purpose, an engine incremental rotation (gear tooth wheel) pick-up 14,, a top dead center pick-up 15, and number one cylinder compression transducer 17 are shown. The engine rotation pick-up produces 256 pulses per revolution for purposes of the preferred embody ment. Engine rotation speed is directly determined and engine position is determined from a combination of signals from pick-ups 14, 15 and 17.

The engine is shown being driven through its flywheel, but may be driven from the other end equally as well. The output of the oil pressure transducers 5 and 6, the engine rotation pick-up 14, and the top dead center pick-up 15 are fed to the instrumentation package 16. In addition, a pressure transducer 17 is shown inserted in the No. 1 cylinder of the engine and the pressure pulse is also fed to the instrumentation package. In operation, an engine to be tested is moved into the station, connected to the oil filter adapter 7, and the rotating drive, top dead center pick-up l5 and cylinder pressure transducer 17 are positioned. The engine is then rotated by means of drive motor 11.

Once stabilized at speed, the oil test is begun by energizing solenoid valve 3. The flow data from pressure transducers 5 and 6, rotation pick-up 14, top dead center pick-up 15 and cylinder pressure transducer 17 is monitored and recorded for at least one full operating cycle, or two revolutions of the‘ engine crankshaft, after which time the solenoid valve is closed and the test is completed.

Fig.1.5 – Engine oil signature analysis system

Fig. 1.5.a shows the plot of the engine oil flow signature produced by the differential pressure across the two pressure transducers 5 and 6 in ‘the oil flow measuring means. This oil flow signature was obtained in a four cylinder engine ‘wherein the No.2 upper rod insert was missing. The importance of the oil signature is that it shows variations of oil flow to the engine for various positions of rotation. As is common with such faults, these faults produce significant variations in the normal oil flow signature which may be identified by a systematic analysis. The present invention suggests such as systematic analysis as a means of detecting common faults in engine manufacturing.

As shown in Fig. 1.5.b, measurement of the oil pressure taken from pressure transducer 6 may also be used, but appears to be a less sensitive indicator.

Fig. 1.5.c shows the plot of the compression in cylinder No. l and serves as a position indicator relative to the cycle of the engine.

Fig. 1.5.d shows pulses produced by the top dead center pick-up. Each pulse corresponds to one half revolution of the crank, the larger spike corresponding to the top dead center of the No. 1 piston.

Other tests may be performed at the same station; for example, compression tests of all the cylinders, manifold vacuum tests, engine oil pump flow and pressure and the like. We are concerned here only with the oil signature and its usefulness as a means of detecting engine assembly faults such as missing or out of tolerance rod or main bearings and/or plugged oil passages.

In 1994, Scourtes et a1. [3] in his paper named “Cold Engine Testing” provides a method and an equipment for testing of engine on the factory production line with the engine being driven by an external motor connected with the engine crankshaft. The engine is not fired up to operate under its own power. In this condition of “cold motoring” data is obtained and analyzed to identify and locate engine faults. Information is obtained which has not previously been available in production line testing.

In accordance with this invention, the ignition circuit is energized with the supply voltage less than normal so that the spark plug will not fire when the gas compression in the cylinder is normal. If firing does result, certain faults are indicated in the spark plug or in engine compression.

Further, in accordance with this invention, the pressure waveform in the intake manifold is analyzed at an engine speed sufficiently low that the peaks and valleys of the waveform can be compared with a reference waveform for a normal engine. This analysis permits certain findings regarding potential faults in the cylinder valves.

Also, in accordance with this invention, the pressure waveforms in the exhaust manifold are analyzed at controlled speed of rotation. This permits identification of certain potential faults in the cylinder valves.

Further, in accordance with this invention, the ignition circuit analysis is coupled with either an intake vacuum pulse analysis or with an exhaust pulse analysis to obtain the broad range of detailed information indicative of certain engine faults.

A complete understanding of this invention may be obtained from the detailed description that follows taken with the accompanying drawings.

Fig.1.5 – Test stand for a cold test system with intake pulse analysis

Fig.1.5 shows a test stand adapted for cold engine testing using intake pulse analysis. The engine 10 under test may be a complete engine and capable of running under its own power except that it is not supplied with a fuel induction system. In the illustrative embodiment, the engine 10 is a V8 engine.

The engine crankshaft 12 is coupled to a variable speed drive motor 14 through a drive coupling 16. A shaft encoder 24 is coupled to the shaft of the drive motor 14 and produces an output signal corresponding to the angular displacement of the crankshaft. The shaft encoder output is coupled to a drive controller 26 which controls the speed of the drive motor 14 at a preset value. The encoder output is also coupled to an input of a data acquisition system 48 which will be described subsequently.

The test stand, as shown in Fig.1.5, is provided with various sensors which are coupled with the engine 10. Such sensors include a top dead center (TDC) pick-up 28 which is suitably coupled with a crankshaft driven pulley or wheel 32 to provide an output pulse each time the engine crankshaft reaches the top dead center (TDC) position.

The sensors also include an intake vacuum transducer 34 which is connected through a vacuum line to the left cylinder bank of the engine by an intake probe connector 35 with the intake passage of the throttle body 36. Similarly, an intake vacuum transducer 38 is coupled to the right cylinder bank of the engine. The probe connector 35 is automatically actuated between an advanced position in which it is sealed to the intake manifold (simulating closed throttle) and a retracted position in which is not sealed (simulating open throttle). A pressure transducer 42 is connected through the pressure line to the #1 cylinder exhaust port which is vented to the atmosphere through a flow restrictor 44.

An oil pressure transducer 46 is coupled to an oil pressure port in the engine. The vacuum transducers 34 and 38 and the pressure transducers 42 and 46 are suitably conventional transducers which develop an analog output signal which is coupled to respective input channels of the data acquisition system 48. The TDC pick-up 28 and the shaft encoder 24 are suitably conventional sensors and adapted to produce digital output signals; the output signals from these sensors are coupled to respective input channels of the data acquisition system 48. The connections between the sensors and the data acquisition system are not shown in the drawings.

The general test procedure is illustrated in the chart of FIG. 3. With the engine 10 under test installed on the test stand with the sensors connected, the test stand is ready for the test procedure. The operator at the test stand uses the computer and other controls to initiate the test. The engine is rotated by the drive motor 14 at controlled speed as indicated in block 102. This is referred to herein as “cold motoring” of the engine.

Under control of the computer 92 the system records data during cold motoring as indicated by block 104. Then, the data is analyzed as indicated by block 106 and the results of the analysis are printed out by the computer as indicated by block 108.

In a cold test procedure to be described herein, the testing utilizes ignition circuit data and analysis for identifying certain engine faults. For certain types of engines and for identifying certain faults, the cold test procedure utilizes intake manifold pulse analysis. For example, this type of testing is especially suited for engines having throttle body fuel injection (the testing is performed without the throttle body installed so that access is gained to the intake manifold).

In other types of engines which is a multi-port fuel injection engine with an intake plenum, exhaust pulse data analysis is preferred because the large volume plenum does not lend itself to pulse sensing.

Fig.1.6 – General test procedure of Scourtes’s Cold Engine Testing Equipment

The general test procedure is illustrated in the chart of Fig. 4. With the engine 10 under test installed on the test stand with the sensors connected, the test stand is ready for the test procedure. The operator at the test stand uses the computer and other controls to initiate the test. The engine is rotated by the drive motor 14 at controlled speed as indicated in block 102. This is referred to herein as “cold motoring” of the engine.

Under control of the computer 92 the system records data during cold motoring as indicated by block 104.

Then, the data is analyzed as indicated by block 106 and the results of the analysis are printed out by the computer as indicated by block 108.

In a cold test procedure to be described herein, the testing utilizes ignition circuit data and analysis for identifying certain engine faults. For certain types of engines and for identifying certain faults, the cold test procedure utilizes intake manifold pulse analysis. For example, this type of testing is especially suited for engines having throttle body fuel injection (the testing is performed without the throttle body installed so that access is gained to the intake manifold).

In other types of engines which is a multi-port fuel injection engine with an intake plenum, exhaust pulse data analysis is preferred because the large volume plenum does not lend itself to pulse sensing. Both intake analysis and exhaust pulse analysis systems will be described below.

CHAPTER 2 – COLD TEST MACHINES

2.1. Cold tester by HIRATA [4]

Fig.2.1 – Cold test equipment developed by HIRATA

Equipment Outline

This piece of equipment is an engine cold test equipment which is used for testing engine function during the final process of the engine assembly line. The equipment performs tests (data sampling and analysis) according to the pallet ID information and is capable of holding the crank at various angles.

The engine data is sampled and analyzed using the base signals, which are provided by the high frequency pulse encoder and are responsible for maintaining an accurate clock, combined with various output signals such as those for rotation torque, NVH, pressure sensors (for air intake, exhaust and oil), ignition passive speed sensor, engine crank angle sensor, and engine cam position sensor.

High accuracy testing is achieved by introducing the temperature, humidity, air pressure and engine oil filter temperature values as (environmental) data parameters.

Fig.2.2 – Cold test equipment developed by HIRATA, interior

Operation Outline

1. ID readout and loading of the pallet with the engine to be tested mounted onto the test area.

2. Engine clamped.

3. Flywheel gear secured and all the instrumentation devices connected.

4. Testing and analysis performed.

5. Crank angle positioning performed.

6. All the instrumentation devices unclamped and then the pallet disengaged.

7. ID write-in and the pallet unloaded; loading of the next pallet.

Features

High-Frequency Pulse Encoder & High-Torque/High-Speed Rotary Motor

The encoder used in this equipment is very accurate and is designed to be subject to less noise due to the fact that its output signals are used as the clock for all analog signals. No reducer is used in the motor in this equipment in order to achieve high-speed, high-torque rotation.

Balanced Main Shaft Rotating Head

Stricter requirements were adopted for the main shaft balance than for the crank shaft balance. By ensuring the main shaft is perfectly balanced after mounting of the rotating head, we have successfully created a piece of equipment with minimum vibration.

Highly Rigid/Vibration-Resistant Base Structure

A Realistic Large Cross-Section Air Intake and Exhaust System

Adoption of a large cross-section piping design that obtains accurate air intake and exhaust pressure for testing. (The cross-section area is equivalent to those of the engine intake and exhaust ports.)

Adoption of a box-shaped base design with a low center of gravity that does not resonate with the engine even when the engine is rotating at a very high speed. (The weight of the base is twice the weight of a normal base.)

Noise Control 1 (large cross-section air intake)

Adoption of a large cross-section air intake design that reduces the air intake whistling sound and achieves correct NVH.

Noise Control 2 (highly rigid exhaust hose and muffler with high exhaust efficiency)

Adoption of a large cross-section hose with low volumetric changes that reduces the continuous bounding sound of the exhaust air, and adoption of the tornado muffler that reduces the exhaust air pressure and noise at the same time.

Noise Control 3 (transparent Lexan cover)

The transparent enforced plastic plate reduces leakage of the sound produced by high-speed rotation, improving the working environment for employees.

Noise-Reducing Wiring

The wire duct structure separates the wires carrying the analog signals susceptible to noise from other wires (power lines in particular).

Profibus Communication for Flexible Control of the Rotation Speed and the Crank Halting Angle

The test mode and the crank halting angle can be controlled as desired for each pallet ID via the Profibus communication.

2.2. Shanghai W-Ibeda High Tech. Group Co – Engine Cold Test Bench [5]

The W-Ibeda Engine Cold Test Bench performs comprehensive test of assembled engines without combustion process. Cold test is usually performed at the end of engine assembly line. The tests can be done with the engine in a Partly assembled status, or in a Fully assembled status:

Partly assembled status

– Intake manifold not installed

– Exhaust manifold not installed

– Wiring harness not installed

Fig.2.3- Engine in partly assembled status

Fully assembled status

– Intake manifold installed

– Turbocharger installed

– Wiring harness installed

Fig.2.4- Engine in fully assembled status

W-Ibeda Engine Cold Test Bench classification

Fig.2.5- Cold Test Bench classification

Typical cold test bench assembly

– The engine flywheel is connected with cold test Equipment via an AC servo motor ,then the engine is driven and tested at different RPM under PC control.

Fig.2.6 – Typical cold test bench assembly

– IPC collects various signals via sensors. Test software processes the signals via special test algorithm and compare with the accelerometer to judge if the engine is assembled correctly, if the components are qualified.

Fig.2.7 – IPC assembly

Characteristics of cold test technology

User is able to find out engine assembling defects and component quality failures in advance via cold test technology to promote engine quality.

With cold test, user can not only perform comprehensive test of engine assembly, but also test quality of engine components.

Cold test technology has many advantages, such as short test cycle, high efficiency, high test accuracy, more test items, no fuel needed, no combustion, low noise, no emission, components of defect engine can be recycled, and so on.

Test procedure

step1 harness test/sensor static test/actuator dynamic test/static ignition test

step2 start torque test

step3 safe oil pressure test/high pressure fuel leakage test/crankshaft cam timing test

step4 high speed oil pressure test/high speed NVH test/VVT test/turbocharger test

step5 intake vacuum test/fuel system dynamic test

step6 low speed oil pressure test/low speed NVH test/discharge pressure test/running torque test

step7 throttle test

Fig.2.8 – RPM distribution through testing steps

COLD TEST vs HOT TEST

Engine defect mapping

Fig.2.9 – Engine defect mapping

System of cold test equipment – Test bench software system

System of cold test equipment – Data query and storage system

a) b)

Fig.2.10 – Data query and storage system

CHAPTER 3 – ACTUAL STATE OF THE SYSTEM

3.1 General Overview

Fig.3.1 – JW Froehlich Cold Test equipment

Cold Test operations are Semi-Automatic, Single Station Engine Cold Test Machines. Each Machine is designed to perform testing operations on fully assembled Engine Variants. The engines are supplied to the Machine clean dry and free from swarf and coolant, completely assembled and mounted to the conveyor platen. Component Orientation prior to machine processing: Engine front facing on platen.

The processed engines are manually de-coupled from the machine and semi automatically offloaded by the operator to the unload conveyor.

The Machine incorporates a local control system and a Human Machine Interface (HMI) control console.

The pneumatic supply to the Machine is provided from the main pneumatic distribution panel located at side of the machine.

The machine consists of the following areas:

• Entry Conveyor – Engine and Platen is transported into the machine to be tested.

• Exit Conveyor – Engine and Platen is transported out of the machine after testing.

• Control Panels – contain the main electrical components such as circuit breakers, safety relays, drives and Sciemetric sensor interfaces.

• Pneumatic Panel – Contains the air components such as valves

• HMI Panel – Contains the main control panel (Human Machine Interface).

Fig.3.2 – JW Froehlich Cold Test equipment

3.2. Tested Part Details

The following images identifies the Engines and connection features that are relevant to the Machine.

Fig.3.3 – Connection features on tested engine

Fig.3.4 – Connection features on tested engine

Fig.3.5 – Connection features on tested engine

3.3 Machine systems

3.3.1 Pneumatic system

The pneumatic supply incorporates the following features.

• A ‘Festo’ shut off / isolator valve that is connected to manually operated soft startup/ quick dump valve. When this valve is operated, it will have the effect of isolating the machines pneumatic system from the factory supply; the air will be dumped into the atmosphere when this valve is closed. This valve has the provision for the use of a padlock for applying LOCKOUT procedure.

• A 40 micron filter / regulator

• A regulator that reduces the factory air pressure to the working pressure of the machine.

Maximum Pressure 3.8 Bar (55 PSI).

The working pressure of this machine is 3.1 Bar (45 PSI)

Control Voltage 24v DC (solenoid valves)

• A soft start solenoid operated valve. This valve provides a controlled increase of pressure to the machine’s fixture offering protection to personnel and equipment. The valve dumps the air automatically by removing power to the solenoid when a selection to OFF is made at a machine control panel.

• The valve drip bowls to collect moisture from the supplied air.

The machine programmable controller monitors the condition within the pneumatic system and controls the machine accordingly.

Fig.3.6 – Pneumatic circuit diagram

3.3.2 Electrical system

Power Supply

The main isolator is situated on the front of the main electrical panel.

Machine Stations

Control station has its own individual transformer to reduce the mains supply to the control voltage of the machine.

Main supply ………………………………………..400-480 Volts 3 Phase 50/60 hertz AC + Earth

Unico Drive……………………………………………………………………………………..400 – 460 V AC

Control supply…………………………………………………………………………24 volts direct current

Live Side Circuit…………………………………………………………………………………. 120 volts AC

The electrical control cabinet incorporates the following:

Power distribution

Relays

Programmable controller

Terminations

Sciemetric Measuring System

Sciemetric Sensor Interfaces

Machine Hardware

The machine comprises of 1 PLC control system and Siemens MP277 Colour HMI screen that is used to display massages during an automatic cycle and to provide local diagnostic messages as well as manual / semi-automatic control functions. The Siemens Human Machine Interface (HMI) is located on the load side of the machine.

The main programmable controller is a Siemens PNIO 317 Programmable Logic Controller (PLC) with Profibus and Ethernet connection, located in the main control panel.

3.3.3 Guarding System

The machine is enclosed within a system of guarding to protect personnel from coming into contact with moving machinery.

Access to the machine is gained via gates locked with Telemecanique, solenoid-controlled, electromechanical Interlocks.

Static Guarding, held captive by toggle clamps is also fitted around the machine, and can be removed using an 8-mm Allen key. The purpose of these guards is to allow for maintenance access only.

To gain access to the machine it is first necessary to stop the machine by pressing the ‘Stop End of Cycle’ softkey on the Siemens HMI Screen. The machine will continue its normal function until the cycle is complete and then stops.

The gate is locked / closed by a handle key that is electrically captivated within the Safety Interlock Switch. To release the key from the switch, the operator must select ‘Request Guard Open’. The action of selecting ‘Request Guard Open’ will allow the guard to be opened in any of the following conditions:

Machine is at Base Position

Machine is in Manual Mode

Emergency Stop has been operated

Control is Not On

3.4 Machine control

3.4.1. HMI screen

Fig.3.7 – Main HMI screen

A Siemens MP277 operator console is used to provide the Human Machine Interface (HMI). The console is used to:

Start and stop the Machine services

Select the operating mode of the Machine

Start and stop the automatic Machine cycle.

Control all automatic and manual operations.

Display diagnostics messages to assist with fault finding

Display general Machine and Station status information.

The console is located on a swivel mount stand located on the entry side on the machine. This Operator Console is used to control the Machine and to view Machine wide status information.

The following diagram shows the layout of the main HMI screen. Some of the keyfeatures of the console are detailed below:

Header and Text Message Area displays general machine status and automatic and manual messages associated with current cycle of the machine including warning, diagnostic and information messages

Fig.3.8 – Header and Text Message Area

HMI ‘Main Screen’ Function Keys

Fig.3.9 – HMI ‘Main Screen’ Function Keys

General – The ‘General’ screen is used to access the general control functions of the machine during automatic and manual cycles. Further to this, it also displays the Engine type, Engine ID and test status.

The ‘Fault Reset’ function key is used to reset safety circuits and also acts as a general fault reset.

Fig.3.10 – HMI’s General screen

Mode – The ‘Mode’ function key is used to selected the machine’s mode of operation i.e. Manual Mode, Automatic Mode, Automatic Cycle, Stop At End Of Cycle, etc.

Fig.3.11 – HMI’s Mode screen

Function of these keys is pre-defined as follows:

Reset Mode Selection– Resets the machine mode so that Manual, Automatic or Semi – Automatic may be selected.

Manual Select – Selects Manual mode and allows the machine operator to manually control all movements.

Automatic Select – Selects Automatic mode and allows the machine be run in Automatic Cycle

Step Mode – Selects Semi-Automatic mode and allows the machine to be cycled Step By Step. Step Mode is predominantly Automatic Mode but allows the machine to be controlled one step at a time via each press of the ‘STEP ‘ ADVANCE’ key

Step Advance – Allows the machine to step through each sequence one step at a time upon each key press. The function is only active when Semi-Automatic mode is selected.

Start Cycle – Allows the machine to cycle in full automatic.

Stop At End Cycle – Allows the machine to finish it’s current automatic cycle and stop in it’s base position.

Stop Immediate – Allows the machine to stop automatic cycle immediately. If this operation is used to stop the machine then it may be requird to recover the machine manually.

Machine Overview

Fig.3.12 – HMI’s Machine Overview screen

This screen is the ‘Machine Overview’ and allows the operator to monitor machine cycle times, component counts etc.

Function of these keys is pre-defined as follows:

Part Count – Allows the machine operator to view daily, shift or total part counts, and also allows resetting of each counter class..

Cycle Time – Allows the machine operator to view current and actual machine cycle times.

PosMon – Allows the machine operator to view / monitor key data that is collated by the machine and sent to the Ford PosMon system.

3.4.2. Control Console Push Buttons

Located below the machine HMI are the main station pushbuttons and indicator lamps:

Fig.3.13 – Control Console Push Buttons

CONTROL ON – Enables the Machine Control On and puts power onto the PLC, HMI and nonmotive control circuits.

CONTROL ON LAMP – Illuminates when Control Is On. The lamp is ‘push to test ‘ type and can be pressed at any time to check lamp functionality.

CONTROL OFF – Disables the Machine Control On circuits and removes power from the PLC and HMI.

CONT SUPPLY FAILED/ PLC NOT RUNNING – Illuminates when Control Is Off or when the PLC is not running. The lamp is ‘push to test’ and can be pressed at any time to check lamp functionality.

GUARD CLOSED/ OPEN – Locks or releases the Machine Access Guard. The switch must be in the ‘CLOSED’ position and the guard must be closed and locked.

EMERGENCY STOP – Operation of the Emergency Stop push button will immediately stop the machine and remove power from all motive components of the machine.

3.4.3. Infeed Side Station Push Buttons

Located at the incoming conveyor side of the machine is a push button station for general cycle control:

ENGINE PASSED – Flashes when the machine has tested the engine and all results have passed, and is on constant when the machine operator has ‘CONFIRMED DISCONNECT’.

The lamp is ‘push to test’ and can be pressed at any time to check lamp functionality.

ENGINE FAILED – Flashes when the machine has tested the engine and any results have failed, and is on constant when the machine operator has ‘CONFIRMED DISCONNECT’. The lamp is ‘push to test’ and can be pressed at any time to check lamp functionality.

START TEST – Flashes when the engine is in the test station and ready to be tested, prompting the machine operator to press the ‘START TEST’ illuminating pushbutton. The lamp is illuminated constantly whist the machine is testing the engine. When in Manual the lamp flashes quickly to alert the machine operator that the Light Guards require resetting prior to carrying out any movements.

CONFIRM DISCONNECT – The machine operator presses this once the engine has finished testing and the operator has disconnect ed the sensor cables, fuel pipes and harness. Upon confirmation the engine is then released from the machine providing the exit is clear.

EMERGENCY STOP – Operation of the Emergency Stop push button will immediately stop the machine and remove power from all motive components of the machine

The Unload Side Station Push Buttons are similar and they provide similar actions.

3.5 Engine Cold Test machine Cycle Overview

Cold Test is designed to perform the following operations on fully assembled engines:

AUTOMATIC LOADING OF ENGINE AND PLATEN INTO PRE STOP

MANUAL RIGGING OF ENGINE

MANUAL RIGGING COMPLETE CONFIRMATION ON PUSHBUTTON

AUTOMATIC LOADING OF ENGINE FROM PRE STOP INTO TEST STATION

AUTOMATIC READ OF RFID TAG TO IDENTIFY ENGINE

MANUALLY CONNECT ENGINE HARNESS AND AIR PIPES

MANUAL CONFIRMATION ON PUSHBUTTON TO START TEST CYCLE

RETURN LIFT AND CLAMP SHOTBOLTS

LIFT AND CLAMP ENGINE

ADVANCE LIFT AND CLAMP SHOTBOLTS

ADVANCE MAIN DRIVE SLIDE INTO FOX POSITION

ADVANCE PULLEY COVER

ADVANCE DRIVE HEAD

ENGAGE FINGERS

SET GLOBAL FAIL BIT ON RFID TAG

RUN STATIC TESTS

ROTATE ENGINE AT 800 RPM

RUN 800 RPM TESTS

ROTATE ENGINE AT 120 RPM

RUN 120 RPM TESTS

ROTATE ENGINE FOR OIL PRESSURE TESTS

RUN OIL PRESSURE TESTS

ORIENTATE ENGINE

WRITE TEST DATA TO RFID TAG

RETURN DRIVE HEAD / DISENGAGE FINGERS

RETURN MAIN DRIVE SLIDE

RETURN PULLEY COVER

RETURN LIFT AND CLAMP SHOTBOLTS

UNCLAMP AND LOWER ENGINE ONTO PLATEN

ADVANCE LIFT AND CLAMP SHOTBOLTS

MANUALLY DISCONNECT HARNESS

3.6 Part testing overview

The engines are transported into the machine via a conveyor system and are mounted on a pallet or carrier. The carrier is positioned by the machine stop. The engine must then be rigged by the machine operator, ensuring that all sensor connections and pipes are correctly connected before commencing the automatic cycle.

Fig.3.15 – Conveyor stopping system

The pallet is secured from raising when the engine is lifted and clamped by the Anti- Lift Bar located at the base of the machine

Fig.3.16 – Anti-Lift bar

Once in position the engine and pallet fixture is in position to be clamped. The fixture and location points of the Lift and Clamp Unit can be seen below:

Fig.3.17 – Lift and Clamp Unit

1. Lift and Clamp Shotbolts

2. Lift and Clamp Cylinder

3. Lift and Clamp Unit

4. Location Points

Main Slide

The main slide is only allowed to advance when the Engine has been lifted and clamped and the Drive Support is raised.

Fig.3.18 – Main slide

Main Slide Unit

Slide Locks

SINAMICS Servo Drive

Slide Lock Pin

Drive Support

Unico Drive Motor

Drive Head And Levers

Drive Coupling

The Main Slide Unit is servo controlled (SINAMICS Drive) for accurate positioning. It should be noted that the slide advances to a preset position for the tested engines.

From the datum of the slide (fully returned and at 0.00 mm) the position is = 446 mm.

It should also be noted that the normal cycle rest position is 195 mm from the slide datum.

The Slide Locks are only released (allowing movement) when the SINAMICS servo drive is moving the slide. During engine testing the slide will be locked in position.

The Slide Lock Pin should be inserted when any planned maintenance is being carried out on the Slide Unit. The Slide Unit must be returned to it’s datum position (0.00 mm) before the pin is inserted.

Fig.3.19 – Slide lock pin

The Drive Support is normally in it’s raised position to support the Drive Shaft when the Drive Head Levers are not engaged onto the Engine. It is only lowered when the Drive is advanced and Levers are engaged.

The Unico Drive Motor is inverter controlled and rotates the Engine to the required RPM for each of the tests. The speed references are different for Fox Engine variants.

The Drive Head and Levers engage once the Slide is advanced into the Test Position. The Drive Head rotates at low rpm to engage the Levers onto the engine.

There are 3 sensors on the Levers, their functions are:

Drive Head Levers Open

Drive Head Levers Closed With Adapter

Drive Head Levers Closed Without Adapter

Fig.3.20 – Drive head

The Drive Coupling connects the Unico Drive Motor to the Drive Head. If the Engine seizes the coupling with disconnect the Drive Motor from the Drive Shaft. The motor will be immediately shutdown and a corresponding message will be displayed on the HMI.

Fig.3.21 – Drive coupling

The Pulley Cover is a metal guard that is advanced during Engine testing to shield the machine operator from any rotational movements. It may only be advanced after the Engine has been Lifted and Clamped.

Fig.3.22 – Pulley cover

Tag Reader

Each Engine Pallet is equipped with of non-contact Tag identification unit that contains information about the Engine and the assemblies that were previously performed on it. The tag unit is mounted underneath the pallet to which the Engine is attached.

Fig.3.23 – Tag location

The machine reads the data from the Tag and stores the necessary data in the PLC. From this data, it is determined which Engine is on the pallet and therefore the complexity of the tests to be performed. Some of this data is transmitted to the Measuring System for further test analysis and transmission to the Quality Server data acquisition system.

The Tag is a self-contained unit, and does not require any line fed power. It receives its energy from the read/ write head. The head transmits a steady carrier signal, which powers the code tag as soon as the required relative distance has been reached. The read / write process takes place during this phase.

Fig.3.24 – Tag reader location

The Tag Control Unit (Moby ASM 456) is controlled via ProfiBus. The status of the unit can be viewed on the HMI but also has status LED’s on the unit.

Fig.3.25 – Tag control unit

CHAPTER 4 – ENGINE TESTING

4.1. Test Sequences

The cold engine testing involves five sequences, as follows:

1 – Static Test [0 RPM]

2 – High Speed Test [1000 RPM]

3 – Noise & Vibration Test [1000 RPM]

4 – Low Speed Test [120 RPM]

5 – Oil Pressure Switch Function Test [45 RPM]

Fig.4.1 – Connector and hoses location – engine top view

Fig.4.2 – Connector and hoses location – engine side view

Fig.4.3 – Connector and hoses location – engine side view

4.1.1 Static test

The static test is performed with the engine at 0 RPM, by gathering data from different sensors, and compares it with the established limits.

4.1.2 High Speed Test [1000 RPM]

4.1.3 Noise & Vibration Test [1000 RPM]

4.1.4 Low Speed Test [120 RPM]

4.1.5 Oil Pressure Switch Function Test [45 RPM]

4.2 Implemented improvements

As a complement of the existing ones, I proposed and successfully implemented the following tests during the cold testing procedure of the engines:

OPS verification on static, 1000rpm, 45rpm;

MTS verification on static and 1000 rpm;

Knock sensor signal analysis.

4.2.1 OPS verification on static, 1000rpm, 45rpm

Adding the check for OPS in the test matrix and improving the test accuracy by correlating test limits in engine functionality

Fig.4.4 – OPS testing

Monitor the OPS during Static test, 1000rpm and 45rpm steps for a better signal accuracy.

Fig.4.5 – OPS testing

Fig.4.6 – OPS testing

Fig.4.7 – OPS testing

Before data: High range of testing limits- couldn’t capture any failure of OPS

Fig.4.8 – OPS testing

After data: Limit range has been reduced and adapted to different engines derivatives

Fig.4.9 – OPS testing

4.2.2 MTS verification on static and 1000 rpm

Adding MTS verification in cold test sequence and differentiate different types of engines by using different test values

Fig.4.10 – MTS verification

Fig.4.11 – MTS verification

Fig.4.12 – MTS verification

With the new settings and limits it is now possible to capture and identify potential failures of the MTS using the Cold test data analysis.

Fig.4.13 – MTS verification – BEFORE

Fig.4.14 – MTS verification – AFTER

Fig.4.15 – MTS verification – BEFORE

Fig.4.16 – MTS verification – AFTER

4.4.3 Knock sensor signal analysis

Introduce knock sensor verification to identify potential abnormal noises and abnormal detonations during engine rotation at 1000rpm.

I used 1000rpm for a better signal accuracy.

Fig.4.17 – Knock sensor signal analysis

Knock data analysis used for detecting out of range values

Fig.4.18 – Knock sensor signal analysis

Fig.4.19 – Knock sensor signal analysis

CONCLUSIONS

REFERENCES

[1] F.R.F. RAMSAY, “Means for testing the ignition systems of internal combustion engines employing spark ignition”, US PATENT – US2427370, 1948;

[2] R. MUDGE et al., “Engine cold testing”, US PATENT – US4448063A, 1984;

[3] G. SCOURTES et al., “Cold engine testing”, US PATENT – US5355713, 1994;

[4] https://www.hirata.co.jp/en/img/business/pdf/cold_tester.pdf

[5] http://www.w-ibeda.com/en/product.asp?id=603

[6] http://www.jwf.com/en/products/cold-test-stands-and-cold-test-systems/