MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 43 Removal HCU (Hydraulic Control Unit) 1. Turn the ignition switch OFF. 2. Pull up the lock (A) of the ABS control unit 26P connector , then disconnect the connector 3. Disconnect the brake tubes from the HECU by unlocking the nuts counterclockwise with a spanner Loosen the 3 ABS HCU bracket bolts, then remove HCU and bracket. 1. Never attempt to disassemble the HCU. 2. The HCU must be transported and stored in. 3. Never shock to the HECU. 4. Remove the 3 bolts, then remove the bracket from HECU. 5. Installation is the reverse of removal Wheel Speed Sensor 1. Remove the front wheel speed sensor mounting bolt
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 44 Remove the mounting bolt fixed on the strut Remove the mounting bolt fixed on the chassis Remove the front wheel speed sensor after disconnecting the wheel speed sensor connector. Measure the output voltage between the terminal of the wheel speed sensor and the body ground. In order to protect the wheel speed sensor, when measuring output voltage, a 100 Ω resister must be used as shown
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 45 Compare the change of the output voltage of the wheel speed sensor to the normal change of the output voltage as shown below: V_low : 0.59V ~ 0.84V V_high : 1.18V ~ 1.68V Frequency range : 1 ~ 2,500Hz
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 46
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 47 6.0 Results/Data Reading / Condition 1)Scan Tools Check Ok/NOT OK 2)HCU Condition OK/NOT OK 3)Wheel Speed Sensor Check OK/NOT OK 4)Trouble shoot OK?NOT OK 7.0 Discussion 1. What are the conditions of the ABS after running all the testing and servicing? 8.0 Conclusion and Recommendation Your conclusion should be related to your practical and theoretical understanding on the related topic. 9.0 References i. Automotive Technology: Principles, Diagnosis, and Service, Third Edition • By James D. Halderman• ©2009 Pearson Education, Inc. ii. https://www.academia.edu/36863521/Anti_lock_Braking_System_ABS_A UTOMOTIVE_SYSTEMS iii. https://www.theengineerspost.com/anti-lock-braking-system
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 48 Electronic Stability Program (ESP)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 49 Electronic Stability Program (ESP) 3.2 Follow the Electronic Stability Program (ESP) diagnosis and servicing a. Components and function of ESP system. b. ESP control modes. c. Problems with the aid of a scan tool and an oscilloscope. Assessment: Practical Task (A) PREPARED BY: EN. MOHD FITRI BIN SAFE'I Ts. MOHD SARHAN BIN OTHMAN
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 50 1.0 Experiment Outcome At the end of the lab session students should be able to: i) Identify components and function of ESP system. ii) Explain ESP control modes. iii) Detect the problems with the aid of a scan tool and an oscilloscope. 2.0 Theory 2.1 Electronic Stability Program (ESP) The electronic stability program (ESP) supports the driver in nearly all critical driving situations. It comprises the functions of the antilock braking system (ABS) and the traction control system but can do considerably more. It detects vehicle skidding movements, and actively counteracts them. This considerably improves driving safety. The electronic stability program (ESP) makes a significant contribution to road safety by preventing vehicles from skidding, thus helping to prevent accidents and save lives. Due to a wide variety of powertrain technologies and degrees of automation, braking systems in vehicles are subject to fundamental changes and must be flexible and modular. Vehicle manufacturers strive for personalization and differentiation, for example through driving dynamics and driving experience. The latest generation of the ESP is a fundamental part of the state-of-the-art braking systems, and perfectly designed to meet the requirements from the automotive megatrends. ESP Indicator
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 51 2.1.1 ESP Components Components of the Electronic Stability Program ESP ® from Bosch 1. ESP-Hydraulic unit with integrated Engine Control Unit (ECU) 2. Wheel speed sensors 3. Steering angle sensor 4. Yaw-rate and lateral-acceleration sensor 5. Communication with engine management ECU Hydraulic unit with attached control unit The hydraulic unit executes the commands from the control unit and regulates, via solenoid valves, the pressure in the wheel brakes. The hydraulic modulator is the hydraulic connection between the master cylinder and the wheel cylinders. It is located in the engine compartment. The control unit takes over the electrical and electronic tasks as well as all control functions of the system.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 52 Hydraulic unit with attached control unit Wheel-speed sensor The control unit uses the signals from the wheel-speed sensors to compute the speed of the wheels. Two different operating principles are used: passive and active wheelspeed sensors (Inductive and Hall-effect sensors). Both measure the wheel speed in a contact-free way via magnetic fields. Nowadays active sensors are mostly employed. They can identify both the direction of rotation and the standstill of a wheel. Wheel-speed sensor Steering-angle sensor The task of the steering-angle sensor is to measure the position of the steering wheel by determining the steering angle. From the steering angle, the vehicle speed and the desired braking pressure or the position of the accelerator pedal, the driving intention of the driver is calculated (desired state).
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 53 Steering-angle sensor Yaw-rate and lateral-acceleration sensor A yaw-rate sensor registers all the movements of the vehicle around its vertical axis. In combination with the integrated lateral-acceleration sensor, the status of the vehicle (actual state) can be determined and compared with the driver’s intention. Yaw-rate and lateral-acceleration sensor ESP Control Modes On the basis of the steering angle, the system recognizes the desired direction of travel. Speed sensors on each wheel measure wheel speed. At the same time, yaw-rate sensors measure vehicle rotation around its vertical axis, as well as lateral acceleration. From this data, the control unit calculates the actual movement of the vehicle, comparing it 25 times per second with the desired direction of travel. If the values do not correspond, the system reacts in an instant, without any action on the part of the driver. It reduces engine power to restore vehicle stability. If that is not sufficient, then
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 54 it additionally brakes individual wheels. The resulting rotary movement of the vehicle counteracts the skidding movement – within the limits of the laws of physics, the vehicle remains safely on the desired course. The ESP® system offers value-added functions that increases comfort and safety. As for example, hill hold control assists the driver when starting off on inclines by independently applying the brakes for around two seconds after the driver has released the brake pedal. The system can also protect vehicles with a high centre of gravity from the risk of rolling over.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 55 1.0 Apparatus/Equipment i) Scan tool ii) Multimeter iii) Oscilloscope 2.0 Safety Precautions i) Wear suitable safety shoe. ii) Fold both lab coat sleeves exceeding elbow part. 3.0 Procedures 3.1 ESP system fault When driving through slippery surfaces, the ESP light will turn on and flash on your dashboard when it’s working. If the light is constant and not flashing on and off, there is a problem associated with ESP. i. Identify the location of OBD2 scanner socket. ii. Connect the scan tool to OBD2 socket.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 56 iii. Scan for any fault code.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 57 3.2 Wheel speed sensor test i. Measure the clearance between the wheel speed sensor and the gear ring. The normal standard value of front wheels should be 1.10 - 1.97mm, and that of rear wheels should be 0.42 - 0.80mm. If the clearance is too large, it will directly affect the accuracy of wheel speed sensor acquisition and data. ii. Check the output voltage part. Lift the vehicle, lift the wheels off the ground, and release the parking brake. remove the wire harness connector of the ABS wheel speed sensor and measure it. Turn the wheel at 1r/s and use a multimeter to measure the output voltage. The front wheel should be 190 - 1140mV, and the rear wheel should be higher than 650mV. If it meets the requirements, it means that the wheel speed sensor is working properly currently. Voltage Test iii. If the sensor is a two-line Hall-type wheel speed sensor. Measure the sensor signal. The Hall type wheel speed sensor outputs the square wave pulse signal,
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 58 which is an anti-interference type. Use an oscilloscope probe hook to clip the signal line, black clip to the body iron clip, and turn the signal plate. The waveform should show of 0.5V-1.5V square wave signal normally. Signal Testing using Oscilloscope Waveform Example iv. If the result of all the test is negative replace the defective sensor.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 59 3.3 Steering Angle Sensor Inspection i. Remove the column cover. ii. Connect the plus (+) end of a oscilloscope terminal A and the minus (-) end of the tester to terminal B (GND). iii. Switch the ignition ON (engine off or on). iv. Turn the steering wheel to the left and right. v. Verify that the voltage from steering angle sensor terminal A to B (GND) is as indicated in the table. • If the voltage can be verified as indicated in the table, go to the next step. • If the voltage is not as indicated in the table, replace the clock spring. vi. Switch the ignition to off. vii. Connect the plus (+) end of a tester to steering angle sensor terminal C and the minus (-) end of the tester to terminal B (GND).
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 60 viii. Switch the ignition ON (engine off or on). ix. Turn the steering wheel to the left and right. x. Verify that the voltage from steering angle sensor terminal C to B (GND) is as indicated in the table. • If the voltage is not as indicated in the table, replace the clock spring. 4.0 Results/Data No. Item of inspection Remark 1 Fault code scan 2 Clearance between the wheel speed sensor and the gear ring 3 Wheel speed sensor output voltage 4 The Hall type wheel speed sensor outputs the square wave pulse signal 5 Voltage from steering angle sensor terminal A to B (GND) 6 Voltage from steering angle sensor terminal C to B (GND)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 61 5.0 Discussion i. What is the basic function of ESP? ii. What are the main components of ESP and its functions? iii. What is the effect of defective wheel speed sensor and steering angle sensor? iv. List down several factors that contribute to ESP system fault. 6.0 Conclusion and Recommendation Your conclusion should be related to your practical and theoretical understanding on the related topic. 7.0 References i. Joseph Beron (2010), Masalah dan Cara Menyelenggara Kereta, Printed by Dawama Sdn. Bhd. ii. G. S. Sethi (2010), Automotive Technology, Published by IBS Buku Sdn. Bhd iii. ABS wheel speed sensor (digital) - voltage. (n.d.). Retrieved March 16, 2023, from https://www.picoauto.com/library/automotive-guidedtests/abs-speed-sensor-digital/ iv. Bad Steering Angle Sensor Symptoms & Replacement/Reset Cost - Car, Truck And Vehicle How To Guides - Vehicle Freak. (n.d.). Retrieved March 16, 2023, from https://vehiclefreak.com/bad-steering-anglesensor-symptoms-replacement-reset-cost/ v. Check and change ABS and wheel speed sensors | HELLA. (n.d.). Retrieved March 16, 2023, from https://www.hella.com/techworld/uk/Technical/Sensors-andactuators/Check-change-ABS-sensor-4074/ vi. Electronic stability program (ESP®). (n.d.). Retrieved March 16, 2023, from https://www.bosch-mobility-solutions.com/en/solutions/drivingsafety/electronic-stability-program/ vii. ESP: Electronic Stability Program. (n.d.). Retrieved March 16, 2023, from https://www.car-engineer.com/esp-electronic-stability-program/ viii. ESP Light: What It Means And How To Fix It. (n.d.). Retrieved March 16, 2023, from https://mechanicbase.com/brakes/esp-light/
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 62 ix. How To Diagnose A Failing Steering Position Sensor | GMParts Center Blog | GM Parts Center. (n.d.). Retrieved March 16, 2023, from https://www.gmpartscenter.net/blog/diagnose-failing-steering-positionsensor x. How to Test a Wheel Speed Sensor? (n.d.). Retrieved March 16, 2023, from https://smtnet.com/news/index.cfm?fuseaction=view_news&news_id=2 5585 xi. Mazda CX-5 Service & Repair Manual - Steering Angle Sensor Inspection - Sensors, Switches, Relays. (n.d.). Retrieved March 16, 2023, from https://www.mcx5.org/steering_angle_sensor_inspection906.html 10.0 Questions Related i. How to diagnose a faulty wheel speed sensor? ii. How to diagnose a faulty steering angle sensor?
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 63 Car Air Conditioning System
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 64 Car Air conditioning system 3.3 Demonstrate air conditioning system diagnosis and servicing. a. The air conditioning system components. b. The air conditioning performance test. c. The refrigerant leak test. d. The refrigerant recovering, evacuating and charging. e. The condenser and evaporator service. f. The hose and line service. g. The compressor service. Assessment: Report PREPARED BY: EN. MOHD FATHI BIN RAMLI
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 65 1.0 Experiment outcome At the end of the lab session students should be able to: a. Identify the air conditioning system components with their functions. b. Method to conduct air conditioning performance test. c. Method to conduct refrigerant leak test. d. Able to operate air conditioning recovery, recycling, and recharging machine. e. Understand the method of servicing condenser and evaporator f. Understand the method of servicing refrigerant hose and compressor g. Able to perform diagnose and troubleshoot air conditioning system. 2.0 Theory 2.1 Introduction The air conditioner is very important for a vehicle because it affects passenger comfort level and safety while driving. The major function of automotive air conditioner must control the temperature, air circulation, purify the air and dehumidify the air. These functions are essential if passenger comfort is to be maintained when the ambient temperature and humidity are high. By performing these functions, the air conditioner maintains the body comfort of the passengers. When a car is driven or parked in the sun, heat enters the vehicle from many sources. These sources include ambient air, sunlight, engine heat, road heat, transmission, and exhaust heat. All these and other miscellaneous heat sources increase the air temperature within the vehicle. In a high ambient temperature situation (e.g., on a 37°C Day), the interior of a vehicle left standing in the sun with windows closed could reach 65-70°C. 2.2 Refrigerant Since 1993 the automotive industry of developed countries has started to use a nonozone depleting refrigerant HFC 134a (hydrofluorocarbon), its chemical name being Tetrafluoromethane. Commonly this refrigerant is referred to as R134a. R134a was selected as a replacement refrigerant for R12 (Dichlorodifluoromethane) because R12 containing chlorine has a major effect to ozone layer depletion. R134a and water have the same abilities to change the state, but R134a can do this more rapidly and at much lower temperature than water. Above -26.3 °C, R134a changes its state, becoming a vapor and absorb large quantities of heat from inside the vehicle. This situation creates the cooling effect
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 66 inside the vehicle. R134a is stored in containers under high pressure. If it is released into the atmosphere, it will boil at -26.3 °C. Figure 1: Table of refrigerant properties There are 3 processes usually involved with refrigerant handling. This 3R method was developed to protect the environment from ozone depletion potential & global warming. Recovery: Following standard ISO 11650 & AHRI 740, recovery is the process of evacuate the existing refrigerant inside the vehicle air conditioning system with assistant of recovery machine and store it inside external recovery cylinder without going any test or further process. Recycling: Following ISO 11650, SAE J1990 or AHRI 740, recycle is the process to reduce contaminants in used refrigerants by separating oil, removing non-condensable, and using devices such as filter- driers to reduce moisture, acidity, and particulate matter. This term usually applies to procedures implemented in the field or a service shop. Reclaiming: Process used refrigerant to new product specifications. This requires a chemical analysis of the product to ensure that it meets the Air-Conditioning and Refrigeration Institute’s Standard 700 for purity. This term usually implies the use of processes or procedures available only at a reprocessing or manufacturing facility.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 67 2.3 Principles of Air Conditioning The air conditioners consist of various parts and components. It is very important for technician to understand the structure and functions of each part and component well and to diagnose troubles with the air conditioners. Air conditioners have a variety of functional parts except for four components such as compressor, condenser, expansion valve, and evaporator. This chapter explains on the basic of actual piping circuit diagram the structure, types, and functions of the component used in the piping. The basic refrigerant cycle illustrated for better comprehension and this figure effectively affects to let technician notice the location of the component in relation to the other component's locations. Figure 2: Refrigerant Cycle 1. Low pressure R134a vapor entering the compressor is compressed to become high pressure/temperature R134a vapor. This is then circulated along with lubricant oil to the condenser. 2. As the high pressure/temperature vapor travels through the condenser, heat is rejected through the cooler ambient air passing over the condenser tubes condensing the vapor into a liquid. 3. This high pressure/temperature liquid then travels through the filter drier onto the expansion valve where a small variable orifice provides a restriction against which compressor pushes. 4. Suction from the compressor pulls the high pressure/ temperature liquid R134a
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 68 through small variable orifice of the TX Valve and into the low-pressure side of the air conditioning system. The R134a is now under low pressure/temperature vapor where heat from the cabin being blown over the evaporator coil surface is absorbed into the colder low-pressure refrigerant. 5. R134a in the LOW-PRESSURE side is COLD and can absorb large quantities of heat from the air moving over the evaporator. The R134a is then pulled through the evaporator and into the compressor. 6. The air conditioning cycle begins again as the R134a vapor is compressed and discharged under pressure. 3.0 Tools/Equipment 1. WAECO ASC 3500 G - Air conditioning service unit for R134a, 26 kg 2. Vacuum pump 3. R134A manifold gauge 4. R134A cylinder 5. Charging scale 6. Recovery cylinder 7. Recovery machine 8. Extension wire cord 9. Electronic leak detector 10. Digital thermometer 11. Safety glass 12. Safety gloves 4.0 Safety Precautions • Work in well-ventilated area. If accidental discharge occurs, ventilate the work area before resuming service. Exposure to refrigerant and lubricant vapors can irritate eyes, nose, and throat. • Protect eyes and exposed skin from any unexpected release of refrigerant. • Ensure that the refrigerant from air conditioning system has been recovered by using WAECO ASC 3500 G - Air conditioning service unit for R134a Machine before loosening fittings or removing parts. Check balance usage capacity filter drier WAECO ASC 3500 G - Air conditioning service unit for R134a Machine before using the machine (if balance usage capacity equal to 10 kg please inform to supervisor). i. Do not store or place refrigerant containers in area over 50⁰C (129
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 69 °F) or in direct sunlight. ii. Do not puncture or incinerate refrigerant containers. iii. Avoid heat source and open flames when working with refrigerant. 5.0 Procedure Attachment: Refer Automotive Air Conditioning Inspection Checklist 5.1 Preparation i. Checking for visual hose damage and chaffing ii. Inspect drive belts for correct tension and damage. iii. Ensure the condenser cooling fins are not blocked with obstructions such as insects, leaves or grass. iv. Condenser fan operates and runs in correct direction. v. Check the cabin air filter. vi. Ensure the evaporator drain hose not blocked vii. Blower fan has all speeds operational and follow speed setting. viii. Fresh air damper fully closed ix. Make sure all window and door fully close 5.2 Refrigerant test i. Open engine hood ii. Place the Air Conditioning Recover, Recycle and Recharge Machine near to vehicle and turn on the machine. After the machine has been turn on, press ‘ENTER’ and select ‘Other Selections’ and press ‘ENTER’ again. You will see 3 options, choose refrigerant test and press ‘ENTER’. After that, the machine will ask whether you want to do a refrigerant test or not. Select ‘YES’. Lastly, the machine will ask you to connect the coupler to the vehicle air conditioner service port. iii. Connect low pressure hose coupling valve to the system filling ports (access service ports) iv. Press ‘ENTER’ on the machine and wait for the result.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 70 5.3 Performance Testing i. Park vehicle in a shaded area. Take note of ambient temperature. ii. Open both front windows and engine hood. iii. Connect both high and low pressure hose coupling valve to the 1 system filling ports (access service ports). iv. Open all dash louvers and adjust to the straight-ahead position. v. Insert digital thermometer probe approximately 50 mm into the center vent louver. vi. Set the air conditioning control to recirculate air position Maximum cooling Highest blower speed vii. Start engine, bring engine speed to 1700 RPM then allow pressure gauge needles to stabilize. viii. Take pressure and temperature readings. Compare this data to the recommendation reading from inspection checklist. Note: Only take pressure and temperature readings when the compressor is engaged. All data must be record to the Automotive Air Conditioning Inspection Checklist. 5.4 Recover, Recycle and Reclaim Air Conditioning System i. After done with performing testing procedure, press ‘ENTER’ and select free selection and press ‘ENTER’. ii. Enter your data car which is plate number, millage or you can either skip this step. iii. Put the pressure increase time in 1 minute and press enter.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 71 iv. Press YES. v. Key in vacuum time 10 minutes. vi. Leak test put the time in 1 minute for it to check and press ‘ENTER’. vii. Press YES for the machine to recycle the refrigerant into the car. viii. Press YES if this machine has your car data. Note: if does not have the data about your car select NO in this step and press ‘ENTER’. ix. Key in value 0ml for PAG Oil ,0ml for Uv Tracer, and refrigerant weight require. Note: refer Automotive Refrigerant Quantity Guide by CoolTech for refrigerant weight. x. Connect the high and low pressure host into the high and low pressure port. xi. Select HP/LP Port xii. Press ‘ENTER’ to start the process and wait until its finished xiii. After finish performance test, press ‘STOP’ xiv. Disconnect both high and low pressure hose coupling valve. xv. Role and keep the host carefully to the machine xvi. After that, press OK so that the machine will suction the remaining gas inside the host. 5.5 Leak Testing i. Prepare electronic leak detector, make sure electronic leak detector design to trace HCFC and HFC gas. ii. Moving the sensing tip of electronic detector slowly around the underside of components and fittings at approximately 5 mm. DO NOT allow the sensing tip to contact components or fittings as false readings and tip damage will occur. iii. Check for leaks around each fitting and connection. iv. Check for leaks around all refrigerant line sensors and switches. v. Check for leaks around the compressor. vi. Check for leaks near any oil deposits on the condenser. vii. Remove insulation or other parts, as necessary to check for leaks the bottom of the evaporator case. (Note: Oil deposits may be an indication of a leak.)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 72 6.0 Troubleshooting Charts 6.1 Compressor
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 73
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 74 6.2 Expansion Valve 6.3 Clutch
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 75 6.4 Abnormal Noise
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 76 7.0 Discussion 1. What are the symptoms to the air conditioning system when refrigerant is overcharging? 2. What will happen to air conditioning system if air and moisture is trap inside it. And give the solution to overcome the situation. 3. During this pandemic Covid-19, it is necessary to ensure good ventilation inside a vehicle especially for grab driver. From your opinion, what is the best method to fulfil this condition? 4. As seen in Malaysia News, some people were dying when fall asleep inside a car for a certain period. What is your idea or innovation to avoid this situation happen again in future? 5. If the results you got in table 2 show the system performance is LESS than described on the performance chart. Discuss the necessary repair on the air conditioning system to fix the problem. 8.0 Conclusion and Recommendation Deduce a conclusion from your result and observation during the practical session. Your conclusion should be related to your practical work, experiment outcome and theoretical understanding on the car air conditioning system. 9.0 References James D. Halderman (2000), Automotive Chasis System. 2nd Edition, Upper Saddle River, New Jersy. ISDN 0-13-079970-x Jack Erjavec (2000), Automotive Technology. 3rd Edition, Delmar Thomson Learning. ISDN 0- 7668-0673-1 Ed. May & Les Si mpson: 2007 Automotive Mechanics; Volume 1: M c. Graw hill, Vocational Education and training TAFE Collage Aust ralia . Ed. May & Les Simpson: 2007 Automotive Mechanics; Volume 2: Mc. Graw hill, Vocational Education and training, TAFE Collage Aust ralia . Uniform Procedures for Collision Repair AC01- Air Conditioning. (1998). Ver.2.3 Inter- Industry Conference on Auto Collision Repair. ICar.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 77 AUTOMOTIVE AIR CONDITIONING INSPECTION CHECKLIST N o Data Collectio n Recomme nded Value Actual Value Remarks Before 1 Refrigerant low pressure (psi) 20 - 40 2 Refrigerant high pressure (psi) 115 - 290 3 Cabin off coil temperature (⁰C) <10 After 1 Refrigerant low pressure (psi) 20 - 40 2 Refrigerant high pressure (psi) 115 - 290 3 Cabin off coil temperature (⁰C) <10 N o Visual Inspectio n Condition Remarks Good Poor 1 Thermostat and switches functionality 2 Speed air blower vs Speed setting 3 Cabin air filter 4 Connection, jointing and fitting for piping and hose 5 Slight glass 6 Oil colour (observe from sight glass) 7 High side pressure sensor 8 Belt drive condition 9 Belt drive tension 1 0 Alignment of belt drive and pulley 1 1 Compressor clutch engagement 1 2 Housing compressor 1 3 Noise and vibration from compressor 1 Condenser Date : ……………………… Vehicle Brand/ Model : ………………………. Millage : ………………………. Reg. Number/ Owner Name : ……………………….. Ref. recovery (kg) : ………………………………… Ref. reclaim (kg) : ………………………………… Oil. recovery (ml) : ………………………………... Oil.refill (ml) : …………………………………
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 78 4 condition 1 5 Condenser blower and fan motor 1 6 Filter drier 1 7 Low pressure service port 1 8 High pressure service port Prepared by, Name: Date: Acknowledge by, Name: Date:
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 79 Continuously Variable Transmission (CVT)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 80 Continuously variable transmission (CVT) 3.4 Follow Continuously variable transmission (CVT) diagnosis and servicing. a. Retrieve diagnostic code using diagnostic tool. b. The hydraulic pressure test. c. The stall and road test. Assessment: Report PREPARED BY: EN. ABU HARFIZ BIN HASSAN EN. SHAIFUL HAZMIR BIN SHAIFUDDIN
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 81 1.0 Experiment Outcome At the end of the lab session students should be able to: iv) Retrieve diagnostic code using diagnostic tool. v) Run the hydraulic pressure test. vi) Run the stall and road test. 2.0 Theory 2.1 Continuous Variable Transmission (CVT) The Continuous Variable Transmission (CVT) consists of the torque converter and gear train. The three-element, one-stage, two-phase type torque converter with a built-in torque converter clutch has been adopted. The gear train of CVT consists of 1 set of multi-disc type clutches, 1 set of multi-disc type brakes, and 1 set of planetary gears which are composed of a sun gear, carrier, annulus gear, 2 sets of pulleys and 1 set of steel belts. CVT CONFIGURATION DRAWING
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 82 2.1.1 CVT components and functions 3.0 Apparatus/Equipment iv) CVT equipped vehicle v) Scan tool 4.0 Safety Precautions iii) Wear suitable safety shoe. iv) Fold both lab coat sleeves exceeding elbow part. 5.0 Procedures 5.1 Retrieve diagnostic code using diagnostic tool. i. Connect scan tool to the data link connector. ii. Turn the ignition switch to the "ON" position. Component Function Forward clutch Operates when moving forward and rotates the primary pulley normally. Reverse brake Operates when moving backward and rotates the primary pulley reversely via the planetary gear. Primary pulley Transfers the rotation from the planetary gear to the secondary pulley via the steel belt. Steel belt Transfers the rotation from the primary pulley to the secondary pulley. Secondary pulley Transfers the rotation from the primary pulley to the differential.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 83 iii. Select "System select" from the start-up screen. iv. Select "Manufacture." v. Make sure vehicle information is correct. vi. Select "ELC-A/T." vii. Select "Diagnostic Trouble Code." viii. If a DTC is set, it is shown. ix. Choose "Erase DTCs" to erase the DTC. 5.2 The hydraulic pressure test. The transmission fluid temperature should be between 70 − 80°C (158 − 176°F) during the test. i. Check the transmission fluid level and temperature. Check engine coolant temperature. • Transmission fluid level: "HOT" mark on the dipstick • Transmission fluid temperature: 70 − 80°C (158 − 176°F) • Engine coolant temperature: 80 − 100°C (176 − 212°F) ii. Raise the vehicle so that the wheels are free to turn. iii. Connect the special tools (3.0 MPa (427 psi) oil pressure gauge and joint and adapter to each pressure discharge port.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 84 NOTE: DR: Torque converter output pressure port PRI: Primary pressure port PL: Line pressure port FWD: Forward clutch pressure port REV: Reverse brake pressure port iv. Restart the engine. v. Check that there are no leaks around the special tool port adapters. For safety, operators must not stand in front of and at the rear of the vehicle during this test. vi. Measure the hydraulic pressure at each port under the conditions given in the standard hydraulic pressure table, and check that the measured values are within the standard value ranges. vii. If the pressure is not within the standard value, stop the engine and refer to the hydraulic pressure test diagnosis table. viii. Remove the O-ring from the port plug and replace it. ix. Remove the special tool, and install the plugs to the hydraulic pressure ports. x. Start the engine and check that there are no leaks around the plugs. 5.3 The stall and road test. i. Check the transmission fluid level, transmission fluid temperature, and engine coolant temperature. • Transmission fluid level: In the "HOT" mark on the dipstick • Transmission fluid temperature: 70 − 80°C (158 − 176°F) • Engine coolant temperature: 80 − 100°C (176 − 212°F)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 85 ii. Raise the vehicle. iii. Pull the parking brake lever, and then fully depress the brake pedal. iv. Start the engine. • Do not maintain the WOT condition for 5 seconds or longer. • When continuing the stall test, make sure that the fluid temperature does not exceed 80•°C (176°F). If the transmission fluid temperature exceeds 80°C (176°F), run the engine at around 1,000 r/min for 1 minute or longer to lower the transmission fluid temperature to 80°C (176°F) or less. v. Move the selector lever to the "D" range and fully depress the accelerator pedal. Quickly read the maximum engine speed at this time. Standard value − Stall speed: 2,400 − 2,900 r/min vi. Move the selector lever to the "R" range, and then repeat the previous step. Standard value − Stall speed: 2,400 − 2,900 r/min 6.0 Results/Data No. Item of inspection Remark 1 Fault code scan 2 Hydraulic Pressure at each port: a. DR: b. PRI: c. PL: d. FWD: e. REV: _________ _________ _________ _________ _________ 3 Stall Test: "D" range "R" range _________ _________ 7.0 Discussion v. What is the CVT? vi. What are the main components of CVT and its functions? 8.0 Conclusion and Recommendation Your conclusion should be related to your practical and theoretical understanding on the related topic.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 86 9.0 References i. Fischetti, Mark (January 2006). "No More Gears". Scientific American. 294 (1): 92– 3. Bibcode:2006SciAm.294a..92F. doi:10.1038/scientificamerican0106 -92. PMID 16468439. ii. ^ Jump up to:a b "How CVTs Work". howsuffworks.com. 27 April 2005. Retrieved 26 August 2020. iii. "CVT Efficiency" (PDF). zeroshift.com. Archived from the original (PDF) on 14 July 2014. Retrieved 22 April 2014. iv. "XTRONIC CVT | Nissan | Technology". Nissan Motor Corporation Global Website. Nissan Motor Co. Ltd. Archived from the original on 20 January 2011. Retrieved 20 September 2021. v. "Pushbelt". Bosch Mobility Solutions. Robert Bosch GmbH. Archived from the original on 8 May 2021. Retrieved 20 September 2021. vi. Ambrósio, Jorge A. C. (5 July 2005). Advances in Computational Multibody Systems. Springer. p. 271. ISBN 9781402033926. Retrieved 8 July 2020. vii. Pfeiffer, Friedrich (2008). Mechanical System Dynamics. Springer. p. 320. ISBN 978-3-540-79436-3. Retrieved 8 July 2020. viii. "CVT Transaxle Steel Push Belt Construction". Weber State University. Archived from the original on 7 November 2021. Retrieved 8 July 2020 – via YouTube. ix. "PIV Vertical Drives – Gayatri Gear". Retrieved 15 September 2020. x. "Positively Infinitely Variable (PIV) Chain". usarollerchain.com. Retrieved 15 September 2020. 10.0 Questions Related iii. How to diagnose a faulty forward clutch? iv. How to diagnose a faulty TCM?
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 87 Supplemental Restraint System (SRS)
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 88 Supplemental Restraint System (SRS) 3.5 Follow Supplemental Restraint System (SRS) diagnosis and servicing. a. The components and function of SRS system. b. Troubleshoot problems based on fault code and manual inspection. c. The servicing and repair of SRS system. Assessment: Practical Task (P) PREPARED BY: EN. MOHAMAD SHUKRI BIN MUDA EN. MOHD NOR HAKIM BIN AB WAHAB
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 89 1.0 Experiment outcome At the end of the session students should be able: a. Retrieve fault code using On Board Diagnostic tool (OBD) b. Inspection of Supplemental Restraint System Airbags. c. Strategy-based troubleshooting and repair. 2.0 Theory SRS Airbags (or Supplemental Restraint System Airbags) are used to offer individual protection beyond the seatbelt in the event of a collision. In the event of a crash, the supplemental restraint system will tell the airbag to go off and open. Airbags will help to prevent the driver and/or passenger from going through the windshield. The airbag itself gets tested every time you turn on your car. A light should go on and then switch back off if the airbag is working properly. If not, the light will remain on. While you can still drive your vehicle if the light remains on, your airbag won’t work, and you run the risk of getting seriously injured in the event of an accident. Ensure that you go get it fixed as soon as possible. The airbags inflate and deflate rapidly upon activation. After airbag deployment, it is normal to notice a smoke-like, powdery residue or smell the burnt propellant. This may consist of corn-starch, talcum powder (to lubricate the bag) or sodium compounds (for example, baking soda) that result from the combustion process that inflates the airbag. Small amounts of sodium hydroxide may be present which may irritate the skin and eyes, but none of the residue is toxic. Routine maintenance of the airbags is not required.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 90 3.0 Apparatus/Equipment i) Vehicle with SRS system ii) Scan Tools iii) Battery iv) Suitable hand tools 4.0 Safety Precautions i. Before performing servicing (including removal or installation of parts, inspection or replacement), be sure to read carefully, then follow the correct procedures described in the repair manual. ii. Work must be started 90 seconds after the ignition switch is turned to the” LOCK” position and the negative (-) terminal cable is disconnected from the battery. (The SRS is equipped with a back-up power source so that if work is started within 90 seconds from disconnecting the negative (-) terminal cable of the battery, the SRS may be deployed.). iii. Do not expose the steering wheel pad, front passenger airbag assembly, side airbag assembly, curtain shield airbag assembly, airbag sensor assembly, front airbag sensor, side and curtain shield airbag sensor assembly, curtain shield airbag sensor assembly or seat position sensor assembly directly to hot air or flames.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 91 iv. Before repairs, remove the airbag sensor if shocks are likely to be applied to the sensor during repairs. 5.0 Procedures FIGURE PROSEDURES IDENTIFY SRS AIRBAG COMPONENTS 1. STEERING WHEEL PAD (with AIRBAG) The inflator and bag of the SRS are stored in the steering wheel pad and cannot be disassembled. The inflator contains a squib, igniter charge, gas generator, etc., and inflates the bag when instructed by the airbag sensor assembly. 2. SPIRAL CABLE (in COMBINATION SWITCH) A spiral cable is used as an electrical joint from the vehicle body side to the steering wheel. 3. FRONT PASSENGER AIRBAG ASSEMBLY The inflator and bag of the SRS are stored in the front passenger airbag assembly and cannot be disassembled. The inflator contains a squib, igniter charge, gas generator, etc., and inflates the bag when instructed by the airbag sensor assembly.
MECHANICAL ENGINEERING DEPARTMENT POLITEKNIK KUCHING SARAWAK DJA40052 – AUTOMOTIVE WORKSHOP PRACTICE 3 92 4. SIDE AIRBAG ASSEMBLY The inflator and bag of the SRS side airbag are stored in the side airbag assembly and cannot be disassembled. The inflator contains a squib, igniter charge, gas generator, etc., and inflates the bag when instructed by the side airbag sensor assembly. 5. CURTAIN SHIELD AIRBAG ASSEMBLY The inflator and bag of the SRS are stored in the curtain shield airbag assembly and cannot be disassembled. The inflator contains a squib, igniter charge, gas generator, etc., and inflates the bag when instructed by the side airbag sensor assembly 6. SEAT BELT PRETENSIONER The seat belt pretensioner system is a component of the front seat outer belt. The seat belt pretensioner cannot be disassembled. 7. SRS WARNING LIGHT The SRS warning light is located on the combination meter. It goes on to alert the driver of trouble in the system when a malfunction is detected in the airbag sensor assembly self-diagnosis. In normal operating conditions when the ignition switch is turned to the ON position, the light comes on for about 3 seconds and then goes off.