Aut 136 automotive hvac
This presentation is the property of its rightful owner.
Sponsored Links
1 / 33

AUT 136 Automotive HVAC PowerPoint PPT Presentation


  • 54 Views
  • Uploaded on
  • Presentation posted in: General

AUT 136 Automotive HVAC. Chapter 9 Heating Systems. OBJECTIVES. After studying Chapter 9, the reader should be able to: Understand how the common automotive heating system works. Explain what parts make up the heating system. Understand how heater temperature is controlled. INTRODUCTION.

Download Presentation

AUT 136 Automotive HVAC

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Aut 136 automotive hvac

AUT 136Automotive HVAC

Chapter 9

Heating Systems


Objectives

OBJECTIVES

After studying Chapter 9, the reader should be able to:

  • Understand how the common automotive heating system works.

  • Explain what parts make up the heating system.

  • Understand how heater temperature is controlled.


Introduction

INTRODUCTION

  • As previously mentioned, the heating system resembles a small version of the engine’s cooling system.

    • Some people consider the heater the most efficient part of the vehicle because it uses waste heat to warm the interior.

  • The heating system is made up of the heater core, hoses, and, in some systems, a control valve.


Introduction1

FIGURE 9-1 The main parts of a vehicle’s heating system are the heater core, blower, heater hoses, and in some cases heater valve. (Courtesy of Everco Industries)

INTRODUCTION


Operation

OPERATION

  • The inlet hose to the heater core connects to an outlet near the engine thermostat, or an area of the engine with the hottest coolant.

  • The outlet hose from the heater core runs to a connection near the inlet of the engine’s water pump, the area with the lowest coolant pressure.

  • When the engine runs, coolant flows through the engine’s water jackets, past the thermostat, and through the heater core.

  • The heated coolant warms the heater core and the air passing through it


Operation1

OPERATION

FIGURE 9-2 Some heater systems use a valve (9) that can shut off the flow of hot coolant to the heater core (2). (Courtesy of Stant Manufacturing)


Operation2

FIGURE 9-3 A heater control valve can be located at any of the positions shown.

OPERATION


Operation3

OPERATION

  • Engine-Off Heater Operation

  • Electric and Hybrid Vehicle Heating Systems


Operation4

FIGURE 9-4 This hybrid vehicle has a pump/bypass that can pump hot coolant through the heater core (b, bottom) when the engine is shut off. During engine operation, the bypass valve (b, top) allows normal circulation. (Courtesy of Toyota Motor Sales USA, Inc.)

OPERATION


Operation5

FIGURE 9-4 (CONTINUED) This hybrid vehicle has a pump/bypass that can pump hot coolant through the heater core (b, bottom) when the engine is shut off. During engine operation, the bypass valve (b, top) allows normal circulation. (Courtesy of Toyota Motor Sales USA, Inc.)

OPERATION


Operation6

FIGURE 9-5 The two PTC, positive temperature coefficient, heater elements help warm the heater core of this hybrid vehicle. (Courtesy of Toyota Motor Sales USA, Inc.)

OPERATION


Heater core

FIGURE 9-6 Heat is transferred from the hot coolant flowing through the water tubes to warm the air flowing through the fins of the core.

HEATER CORE

  • The heater core is a heat exchanger much like the condenser, evaporator, and radiator.

  • Heat transfers from the coolant, to the fins, and to the air passing through the core.

  • As with other heat exchangers, there is a large area of fin-to-air contact to allow sufficient heat transfer and air flow.


Heater core1

FIGURE 9-7 The critical dimensions needed when replacing a heater core. (Courtesy of Four Seasons)

HEATER CORE


Heater core2

FIGURE 9-8 Two examples of the many shapes and sizes of heater cores. (Courtesy of Four Seasons)

HEATER CORE


Hoses

FIGURE 9-9 Heater hose uses reinforced rubber construction (a) and is available in straight or molded (b) shapes. (Courtesy of Veyance Technologies, Inc.)

HOSES


Hoses1

FIGURE 9-10 Some vehicles use quick-connect couplings for the heater hose connections. The hose is merely slid firmly onto the connector to make the connection. It should be disconnected carefully using a suitable tool. (Courtesy of Four Seasons)

HOSES


Hoses2

HOSES

  • Restrictors

    • Some systems include a restrictor to slow the coolant velocity as it passes through the heater core.

    • The restrictor can be part of the manifold fitting or the inlet heater hose assembly.

    • The major purpose of the restrictor is to slow the flow rate in order to reduce noise and internal heater core erosion.


Control valves

CONTROL VALVES

  • Most heater control valves are on–off valves and are used to make the core either hot or cold.

    • Some valves are designed to modulate and adjust the flow so the core temperature can be controlled to all points between hot and cold.

    • Some valves allow a return flow, so the coolant still circulates, bypassing the core when the valve is shut off.


Control valves1

FIGURE 9-11 A heater control valve can be operated manually (a), by vacuum control (b), through a mechanical cable (c), or by a thermostatic element (d). (a courtesy of Four Seasons; b, c, and d are courtesy of Stant Manufacturing)

CONTROL VALVES


Dual heating systems

FIGURE 9-12 The control panels for a vehicle with front and rear climate control systems. (Courtesy of Chrysler LLC)

DUAL HEATING SYSTEMS

  • Many vehicles with rear A/C systems include a heater in the rear unit.

  • These rear units include a heater core and temperature-blend door


Aftermarket heating systems

AFTERMARKET HEATING SYSTEMS

  • Before heaters became standard equipment, aftermarket heating systems were installed in many cars.

  • Today, these units are primarily designed for RVs, vans, and motor homes.

  • They are normally installed after the vehicle has been built, by shops that specialize in heating and A/C service or RV van conversion and repair.


Aftermarket heating systems1

FIGURE 9-13 This aftermarket heater assembly (a) contains a heater core (9) and blower (1–4). An exploded view is shown in (b). (Courtesy of Red Dot)

AFTERMARKET HEATING SYSTEMS


Summary

SUMMARY

  • Heaters use hot coolant from the engine cooling system.

  • Some vehicles have engine-off heater operation using an electric pump and control valves.

  • The heater core resembles a small radiator, and it is connected to the engine by a pair of hoses.

  • Some vehicles use a coolant flow valve to control heater output temperature.

  • Some vehicles use dual heater systems; these can be OEM or aftermarket.


Review questions

REVIEW QUESTIONS

  • The heater core inlet hose connects to the engine close to the _________, and the outlet hose is connected close to the water pump _________.

  • The heat from a vehicle’s heater comes from the engine _________.

  • A(n) _________ _________ heater core is made from a set of stamped metal plates.

  • Critical dimensions of a heater core include the _________, _________, and _________ of the core plus the _________ and _________ of the tubes.


Review questions1

REVIEW QUESTIONS

  • A hose clamp of good design will not _________ the hose, clamp completely _________ the hose, and compensate for _________ and _________.

  • Some modern heater hoses use _________-_________ couplings at the heater core.

  • Temperature of the air leaving the heater ducts is controlled by a(n) _________ that regulates the coolant flow through the core or by a(n) _________-_________ door.

  • Some vans will use _________ _________ systems to help warm up the rear compartment.


Chapter quiz

CHAPTER QUIZ

  • Two students are discussing the coolant flow through a heater core. Student A says that heated coolant enters the heater inlet hose close to the engine thermostat. Student B says the coolant from the heater core returns to the water pump outlet. Who is correct?

    • A only

    • B only

    • Both A and B

    • Neither A nor B


Chapter quiz1

CHAPTER QUIZ

2.Two students are discussing the heater core. Student A says that a heater core is a heat exchanger much like a radiator. Student B says the coolant from the engine brings the heat to the heater core. Who is correct?

  • A only

  • B only

  • Both A and B

  • Neither A nor B


Chapter quiz2

CHAPTER QUIZ

3.Two students are discussing heater hoses. Student A says that most hoses have an inside diameter of about one inch or larger. Student B says the heater core inlet hose is usually larger than the outlet. Who is correct?

  • A only

  • B only

  • Both A and B

  • Neither A nor B


Chapter quiz3

CHAPTER QUIZ

4.Heater hoses are attached to the core using _________.

  • Clamps

  • quick-connect couplings

    Which is correct?

  • A only

  • B only

  • Both A and B

  • Neither A nor B


Chapter quiz4

CHAPTER QUIZ

5.Two students are discussing the heater output temperature. Student A says that a valve is used to reduce coolant flow through the core when less heat is desired. Student B says that most modern systems use a blend-air door to control the heat/cooling output. Who is correct?

  • A only

  • B only

  • Both A and B

  • Neither A nor B


Chapter quiz5

CHAPTER QUIZ

6.The control for most heater control valves is either a Bowden cable or mechanical.

  • True

  • False


Chapter quiz6

CHAPTER QUIZ

7.Two students are discussing heater temperature control. Student A says that a control valve will be wide open when full heat is desired. Student B says the coolant control valve should go wide open if the vacuum line is disconnected. Who is correct?

  • A only

  • B only

  • Both A and B

  • Neither A nor B


Chapter quiz7

CHAPTER QUIZ

8.An aftermarket heater system consists of _________.

  • a core

  • a blower

  • control switches

  • All of these


  • Login