chap65 pps Automotive technology at University of Cambridge

start Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 65, the reader should be able to: • • • • • Safely depower a hybrid electric vehicle Safely perform high-voltage disconnects Understand the unique service issues related to HEV highvoltage systems Correctly use appropriate personal protective equipment (PPE) Explain hazards while driving, moving, and hoisting a hybrid electric vehicle Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 KEY TERMS: ANSI • ASTM CAT III • DMM • floating ground HV • HV cables • IEC • Linesman’s gloves NiMH • OSHA Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 HIGH-VOLTAGE SAFETY EQUIPMENT Rubber Gloves Be sure high-voltage (HV) linesman’s gloves are available, rated at least 1,000 volts, class “0” by ANSI/ASTM The Occupational Safety and Health Administration (OSHA) requirements specify that HV gloves get inspected every six months by a qualified glove inspection laboratory Use an outer leather glove to protect the HV rubber gloves Inspect the gloves carefully before each use High voltage and current (amperes) in combination is fatal See Figures 65-1 & 65-2 WARNING: HV cables and wiring are orange in color High-voltage insulated safety gloves and a face shield must be worn when carrying out any diagnostics involving the high-voltage systems or components Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 65–1 Rubber linesman’s gloves protect the wearer from a shock hazard NOTE: The high-voltage insulated safety gloves must be recertified every six months to remain within OSHA guidelines Figure 65–2 Wearing leather gloves over the linesman’s gloves helps protect the rubber gloves from damage Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Before using the rubber gloves, they should be tested for leaks using the following procedure: Roll the glove up from the open end until the lower portion of the glove begins to balloon from the resulting air pressure Be sure to “lean” into the sealed glove to raise the internal air pressure If the glove leaks any air, discard the gloves The gloves should not be used if they show any signs of wear and tear Figure 65–3 Checking rubber linesman’s gloves for pinhole leaks Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 CAT III–Rated Digital Multimeter Hybrid electric vehicles are equipped with electrical systems whose voltages can exceed 600 volts DC A CAT III–certified digital multimeter (DMM) is required for making measurements on these high-voltage systems Eye Protection Should be worn when testing for high voltage, considered by many to be anything over 60 volts Most hybrid electric systems use voltages higher than this threshold If the system has not been powered down or has not had the high-voltage system disabled, a shock hazard is always possible Even when the high-voltage (HV) system has been disconnected, there is still high voltage in the HV battery box Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 FIRST RESPONDER PROCEDURES Identifying a Hybrid Vehicle To confirm whether a vehicle is a hybrid, look for the word “HYBRID” on the rear of the vehicle Orange cables underhood or shielding bolted to the underside of the vehicle, indicates the vehicle is a hybrid Figure 65–4 This Honda Accord hybrid is identified by the emblem on the rear deck lid Figure 65–5 A hybrid electric vehicle can often be identified by looking for orange-colored cables under the hood, as well as other markings on the engine cover Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Except for the Honda Insight and the Toyota Prius, there is very little difference in the exterior or interior appearance of hybrids, compared to those of their gasoline-powered counterparts Power Source The main power source of all hybrids is a conventional internal combustion engine (ICE) During start-up and acceleration, an electric motor provides assistance to the engine During braking and deceleration, the motor acts as a generator, recharging both high-voltage and the 12-volt battery 12-Volt Battery A conventional flooded-type lead-acid 12-volt battery, powers all standard electronics Most are nonspillable absorbed glass mat (AGM) designs This battery also provides power to the high-voltage battery control systems Disconnecting or cutting the negative cables to the battery may be necessary in some emergency situations Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Fuse Box Most hybrid electric vehicles have a fuse box in the engine compartment Removing the main fuse from this box may be required in some emergency situations High-Voltage Battery Module The electric motor is powered by a high-voltage battery module Because the battery module is recharged by the electric motor whenever the vehicle decelerates or by the generator during cruise conditions, the battery never needs external charging The high-voltage battery modules are often in plastic containers, and these cells are placed within a sturdy metal box See Figure 65–6 Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 10 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 MOVING AND TOWING A HYBRID If a disabled vehicle needs to be moved a short distance (to the side of the road) and the vehicle can still roll on the ground, the easiest way is to shift the transmission into neutral and manually push the vehicle To transport a vehicle from an emergency location, a flatbed truck should be used if the vehicle might be repaired If not available, the vehicle should be towed by wheel-lift equipment with front wheels off the ground (FWD hybrid electric vehicles only) Do not use sling-type towing equipment In the case of 4WD HEVs such as the Toyota Highlander, only a flatbed vehicle should be used Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 35 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Moving the Hybrid Vehicle in the Shop After an HEV has been serviced, it may be necessary to push the vehicle to another part of the shop or outside as parts are ordered Make sure to tape any orange cable ends Permanent magnets are used in all the drive motors and generators and it is possible that a high-voltage arc could occur as wheels turn and produce voltage Another way to prevent this is to use wheel dollies Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 36 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 A sign that says “HIGH VOLTAGE—DO NOT TOUCH” could also be added to the roof of the vehicle Keep the keys out of the vehicle and safely stored Figure 65–11 Use of a warning cover over the steering wheel helps others realize that work is being performed on the high-voltage system and that no one is to attempt to start or move the vehicle Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman Figure 65–12 A lock box is a safe location to keep the ignition keys of a hybrid electric vehicle while it is being serviced Notice that this lock box has two separate locks so it would require two people to open, helping to insure that no harm is done by accidentally attempting to start a HEV 37 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Removing the High-Voltage Batteries The HV battery box should always be removed as an assembly, placed on a rubber-covered work bench, and handled carefully All parts, especially capacitors, should be checked for voltage while wearing HV rubber gloves Always check for voltage as the components become accessible before proceeding Figure 65–13 Insulated tools, such as this socket set, would provide an additional margin of safety to the service technician when working around high-voltage components and systems When removing high-voltage components, it is wise to use insulated tools Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 38 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Storing the High-Voltage Batteries If a hybrid is to be stored for any length of time, the state of charge of the HV batteries must be maintained If possible, start the vehicle every month and run it for at least 30 minutes to help recharge the HV batteries This is necessary because NiMH batteries suffer from self-discharge over time High-voltage battery chargers are either not available or are hard to find even at a dealer If the HV battery SOC was over 60% when it was put into storage, the batteries may be stored for about a month without a problem If the SOC is less than 60%, a problem with a discharged HV battery may result Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 39 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Hoisting a Hybrid Vehicle When hoisting or using a floor jack, pay attention to the lift points Orange cables run under the vehicle just inside the frame rails on most hybrids Figure 65–14 The high-voltage wiring on this Honda hybrid is colored orange for easy identification Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 40 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Some Honda hybrid vehicles use an aluminum pipe painted orange that includes three HV cables for the starter/generator and also three more cables for the HV air-conditioning compressor If damage occurs to any high-voltage cables, the MIL will light up and a no-start will result if the PCM senses a fault The cables are not repairable and are expensive The cables can be identified by an orange outer casing, but in some cases, the orange casing is not exposed until a black plastic underbelly shield is removed first Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 41 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Paint Ovens Nickel metal hydride (NiMH) batteries may be damaged if exposed to high temperatures, such as in a paint oven The warning labels on hybrid vehicles specify that the battery temperature should not exceed 146°F (63°C) HV Battery Disposal The hybrid electric vehicle manufacturers are set up to ship NiMH battery packs to a recycling center There is an 800 number located under the hood or on the HV battery pack that can be used to gain information on how to recycle these batteries Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 42 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 High Voltage Battery SOC Considerations NiMH batteries not store well for long lengths of time After a repair job, or when the HV system has been powered down by a technician and powered up again, not be surprised if a warning light(s), codes, and the MIL are illuminated If everything was done correctly, a couple road tests may be all that is required to reset the MIL The HV battery indicator on the dash may also read zero charge level After a road test, the HV battery level indicator will most likely display the proper voltage level Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 43 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 INSULATION TESTER Whenever a hybrid electric vehicle is in an accident or has been submerged in deep water, the insulation should be tested before the high-voltage circuits are activated An insulation tester, often called a megaohmmeter, such as the Fluke 1587, is used One meter lead is connected to one of the high-voltage cables and the other lead is connected to a good, clean body ground There should not be any continuity • The tester applies a test voltage on the meter leads • The tester then measures the voltage and the current • the tester then calculates the resistance and displays the reading Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 44 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 PHOTO SEQUENCE HV Glove Use Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 45 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 PHOTO SEQUENCE HV Glove Use Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman (cont.) 46 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY Personal protective equipment (PPE) for work on hybrid electric vehicle includes the wearing of high-voltage rubber gloves rated at 1,000 volts or more worn with leather protective gloves to help protect the rubber gloves A digital meter and meter leads that meets CAT III standards should be used when working around the high-voltage section of a hybrid electric vehicle Safety glasses and a face shield should be worn whenever working around the high-voltage circuits of a hybrid electric vehicle Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 47 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY (cont.) The high-voltage system can be shut off by disconnecting the high-voltage circuits and being sure the ignition is off Disconnecting the 12-volt battery is additional security that the high-voltage circuits are depowered For most situations, first responder actions should be the same as if the vehicle were conventional When servicing a hybrid electric vehicle, always observe recommended safety procedures Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 48 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 end Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman 49 ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458