1. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 32 Intake and Exhaust Systems

2. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Vacuum Systems Vacuum in the intake draws air into the cylinders Also used to operate or control systems and/or components Vacuum is supplied by a network of hoses, tubes, and control valves

3. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Vacuum refers to any pressure lower than atmospheric pressure Higher altitude = Lower pressure Pressure at sea level is 14.7 psi 14.7 psi is usually 0 on a pressure gauge, or 0 psig Vacuum expressed in inches of mercury (in. Hg), kilopascals, or bars Vacuum Basics

4. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Normal atmospheric pressure at sea level is about 1 bar or 100 kilopascals

5. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Engine Vacuum It is produced by the downward movement of the piston on the intake stroke The amount depends on the cylinder’s ability to form a vacuum and the intake’s ability to fill the cylinder

6. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Diagnosis and Troubleshooting Vacuum problems can produce or contribute to the following symptoms: StallingPoor starting BackfiringRough idle Poor accelerationRich or lean stumble OverheatingDetonation or knock PingingRotten egg odor Poor fuel economy

7. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Inspect for: – Improper routing – Disconnections – Cuts – Kinks – Wear near hot spots – Damaged valves, storage devices Diagnosis and Troubleshooting (Cont.)

8. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Vacuum Leaks

9. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Vacuum Test Equipment Vacuum gauge connects to the engine Smoke machines help locate vacuum leaks

10. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

11. Knowledge Check Technician A says vacuum is pressure less than atmospheric pressure. Technician B says vacuum starts at zero atmospheric pressure. Who is correct?

12. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Air Induction System Directs and filters outside air into the cylinders Make sure intake ductwork is properly installed and all connections are airtight Air leaks after the airflow sensor will cause driveability problems

13. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

14. Primary purpose is to prevent airborne contaminates and abrasives from entering the cylinders Provides filtered air for the PCV system Air Filter/Cleaner

15. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

16. Intake Manifolds Distribute the clean air or air-fuel mixture as evenly as possible to each cylinder Can be classed wet or dry manifolds Often house the thermostat and EGR Modern manifolds are aluminum or plastic Designs vary by engine type

17. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

18. Design Variations Runner length is designed to achieve the best performance at particular speeds Short runners – more HP at higher speeds Fast moving air enters intake and stops at closed intake valve This air then bounces around in the runner

19. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Variable Intake Runners PCM controls plenum area and/or length of runners according to engine speed Increases volumetric efficiency at more than one range of engine speed Common use is changing path of air between short and long runners

20. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

21. Servicing an Intake Manifold Should be replaced if cracked or if sealing surfaces are damaged Always use new gaskets and seals Check TSBs for updated gasket designs Use guide bolts to ensure proper alignment Torque fasteners to specifications and in the correct sequence

22. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

23. Intake Manifold Components

24. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check How can variable intake runners increase performance?

25. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Forced Induction Systems Engines can not produce full power at high speeds because the do not receive enough air Power output is related to the amount of air compressed in the cylinders More power can be produced by pressurizing the intake mixture before the cylinder Turbo and superchargers accomplish this

26. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Intercoolers Cools the turbocharged or supercharged air before it reaches the cylinder When compressed, the air gets hotter This reduces air density and power output Heat removal increases air density, improves efficiency, and output

27. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Intercooler

28. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Turbochargers Exhaust driven air pumps Exhaust gases spin the turbine blades The turbine turns the compressor wheel Air is compressed and sent to the cylinders Used on gas and diesel engines

29. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Turbine (hot wheel) Turbine shaft Compressor (cold wheel) Waste gate valve Actuator Turbocharger Components

30. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Typical Turbocharger System

31. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Construction The turbine spins at very high speeds The waste gate controls the pressure of air delivered to the cylinders Typically begins to compress air around 2000 engine RPM Turbo boost describes the positive pressure 10 psi of boost equals 24.7 psi

32. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Turbo Lag The lack of an immediate response Caused by the exhaust gas requiring time to build enough energy to spin the turbo fast enough to respond to engine speed

33. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

34. Waste Gate Valve Excessive output pressure can cause driveability concerns and engine damage The waste gate allows a certain amount of exhaust gas to bypass the turbine when boost reaches a certain level Can be PCM or manifold pressure controlled

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36. Turbo Lubrication and Cooling The turbo must be well lubricated and cooled – exhaust temperatures can surpass 1800°F (982°C) Compressor wheels can spin over 200,000 RPM

37. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Various Turbocharger Designs Variable Nozzle Turbine – The size of the area through which the exhaust flows is variable – Do not use a wastegate

38. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Various Turbocharger Designs Twin Turbochargers – Some applications use one for each bank – Others use one turbo that spins up faster than the other, providing more sustained power

39. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Turbocharger Inspection Listen to sounds from the turbo system Inspect the exhaust system for leaks Check for intake system leaks Waste gates may have carbon buildup Check ignition timing, vacuum hoses, knock sensor, and O 2 sensor

40. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Lack of Lubricant – Is commonly caused by infrequent oil changes or using the wrong oil Ingestion of Foreign Objects Contamination of Lubricant – May be caused by defective seals Turbocharger Problems

41. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

43. Replacing a Turbocharger Plug the intake and exhaust ports and oil inlet Put about 20cc (0.68 oz.) of oil in new unit and turn compressor wheel several times Ensure the engine oil is clean and full

44. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Maintenance Engine oil and filter must be maintained Many manufacturers recommend specific types of oil Run the engine for at least 30 seconds after the oil change Ensure the air cleaner is maintained

45. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Turbo Start-Up and Shutdown Leading cause of failure is poor lubrication If engine has not run for a day or more, start and let idle 3 – 5 minutes Never operate under load if there is less than 30 psi oil pressure Idle the engine for 20 – 120 seconds before shutdown

46. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check What are two ways to reduce turbo lag?

47. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Superchargers Positive displacement air pumps driven by the crankshaft Improve HP and torque by increasing air pressure and density in the intake An oil cooler is typically used

48. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

49. Supercharger Operation Air enters from a remote mounted air cleaner and airflow meter Once past the throttle plates, air passes through the inlet plenum Air is pressurized by the spinning rotors The heated air then passes through an intercooler

50. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Air Flow Through a Supercharger

51. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Supercharger Bypass System May be electronically or vacuum controlled The bypass allows the supercharger to idle when power is not needed With the bypass closed, boost can reach about 12 psi

52. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Supercharger Bypass

53. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Supercharger Designs Roots Type – Uses a pair of three lobed rotor vanes – Belt driven via the crankshaft G-Lader Type – Uses a scroll shaped rotor – Spins around an eccentric shaft

54. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. The scroll shaped rotor looks similar to the scroll mechanism of an A/C compressor

55. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Supercharger Problems Similar to turbocharger problems Refer to service information for specific symptoms and repairs

56. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Maintenance Normally superchargers have their own oil supply Check and correct oil level periodically Inspect regularly for leaks Inspect induction system for leaks and filter condition

57. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Supercharger and Turbocharger A few vehicles use a “twincharger” system The supercharger boosts power at low speeds The turbo boosts power at high speeds Used on direct injection engines Maximum boost is around 36 psi at 1500 rpm

58. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust manifold Exhaust pipe and seal Catalytic converter Muffler Resonator Tailpipe Heat shields Clamps, brackets, and hangers Exhaust gas oxygen sensors Exhaust System Components

59. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

60. Exhaust Manifold Collect and direct exhaust gases Can be cast iron or stamped steel Designed for particular engine/chassis combinations Proper tuning can create a partial vacuum that draws the exhaust out of the cylinder

61. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust Pipe and Seal Runs between the exhaust manifold and catalytic converter Exhaust gaskets or seals are used to prevent leaks between components Most gaskets and seals need replaced if the exhaust pipe is being replaced

62. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust Pipe

63. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Catalytic Converters Located before the muffler The extreme heat in the converter oxidizes the exhaust Converts undesirable exhaust gases into harmless gases Reduces exhaust noise

64. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Catalytic Converter

65. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Catalytic Converters (Cont.) Late model vehicles use a three-way converter (TWC) Treats all three controlled emissions

66. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Can be damaged or plugged Often caused by overheating due to raw fuel entering the converter A plugged converter restricts exhaust flow Function can be checked with exhaust gas analyzer Use a vacuum or back pressure gauge to check for restriction Converter Problems

67. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Mufflers Has baffles, chambers, tubes, or holes to break up sound Two common types: – Reverse flow – Straight through flow Produces some backpressure, which affects engine breathing

68. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

69. Resonator Acts as a second muffler or silencer Further reduces exhaust noise Located toward the end of the exhaust system Looks like a small muffler

70. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Tailpipe Last pipe in the system Releases exhaust gases beyond the backend of the vehicle

71. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Heat Shields Protect other parts from exhaust heat Usually made of pressed or perforated sheet metal

72. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Clamps, Brackets, and Hangers Used to properly join and support the exhaust system

73. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Knowledge Check What are two exhaust system problems that can affect engine performance?

74. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust System Service Any physical damage can result in partial restriction or blockage or leaks: – Can result in loss of power and backfiring – Exhaust restriction causes increased noise and emissions – Leaks can cause illness or death

75. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust Leak

76. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Holes, road damage, and split seams Kinks or dents Discoloration or rust Broken or missing hangers Loose tailpipes or other components Signs of catalytic converter overheating: – Bluish or brownish converter shell Exhaust System Inspection Items

77. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Improper Repairs

78. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Exhaust Restriction Test Most common check is with a vacuum gauge Connect gauge to manifold vacuum Bring engine up to 2000 – 2500 RPM Watch gauge: – Reading should stay high and steady – A falling reading indicates a restriction

79. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Replacing Components Check clearance points Make sure new parts match the old parts Allow the system to cool Soak all rusted fasteners with a penetrating oil

80. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Common Exhaust Tools

81. © 2015 Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part. Induction Heating Safer than using a torch Limits heat to component being heated Makes exhaust work easier