Komatsu Repair Manual

Product Overview

Proper service and repair are crucial for ensuring the safe operation of machines. This Komatsu repair manual offers effective and safe techniques for service and repair, some of which require specialized tools designed by Komatsu. The guidance provided is thorough and essential for maintaining machinery performance, preventing common issues, and ensuring longevity.

Table of Contents

• Index and Foreword
• Specification
• Structure, Function, and Maintenance Standards
• Standard Value Table
• Testing and Adjusting
• Troubleshooting
• Disassembly and Assembly
• Maintenance Standard
• Appendix
• Circuit Diagrams
• Index

Manual Extract: Operation of EGR Valve

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The EGR valve operates as follows:

1. The engine’s boost oil pump directs oil into port (C) of the EGR valve, while control pressure from the EPC valve solenoid enters port (E).
2. The spool (4) shifts to the right due to the spring (5) force, closing valve (1) by spring (2) pressure. Exhaust gases from the EGR cooler are thus halted from flowing to the intake side.
3. To open valve (1), control pressure from the EPC valve enters port (E), balancing with spring (5) to position spool (4) correctly.
4. Once the notch of power piston (3) is uncovered, oil flows through port (C), driving the power piston (3) left.
5. The force generated by the power piston (3) reaches the balance point between force (Fp) and spring (2) reaction force (Fs), thus opening the EGR valve (1) for gas flow to the intake side.
6. The balance of force ensures the servo mechanism moderates any external influences on valve (1), maintaining proper function without imparting unwanted pressure on spool (4).
7. The EGR valve lift sensor monitors the displacement of spool (4) to ensure optimal operation.