Small Engine Valves Prepared by: Brian D. Alexander Virginia Tech Edited by CTAE Resource Network February 2011.

Slides:

Advertisements

Similar presentations

Unit C: Agricultural Power Systems

Advertisements

Compression Systems Small Engines.

Chapter 3 Engine Operation

Cylinder Head Machining ‘Surfacing’ the head ‘Surfacing’ the head Machining the mating surface or the head Machining the mating surface or the head Makes.

How Many Small Engines do you have at home? Do you understand how they work and what makes them run? This presentation is from Virginia Tech and has not.

1 Automotive Engines Part 4 (Cyl. Head). 2 Cylinder Head.

Small Engine Theory What is the purpose of a Small Engine?

BASIC ENGINE TESTING.

Engine Upper End Chapter 18.

MANIFOLDS and HEADS n Chapter 8 n Classroom Manual n Page 179 CBC AUTOMOTIVE RK.

Engine Components Chapter #6.

Engine Classification

SMALL ENGINES ENGINE OPERATION FOR A FOUR STROKE ENGINE.

Engine Systems and Components

Valve train inspection Inspect... Cylinder head castings Valves Guides Springs Cam and lifters Rocker arms and push rods Timing chains and gears Copyright.

Systems of the Engine.

Camshaft, Rocker Arms, Pushrods (Valve Train)

Two and Four Cycle Engines

Two Stroke Engine Operation Automotive Technology 1 Mr. Wasacz.

At the end of thirty minutes, 90 % of the students are expected to a. Define Engine Valve b. Identify the types of engine valves c. Appreciate the function.

VALVES LESSON SEVEN. 1.DEFINITION A device used to regulate or control the flow of fluids ( liquid, air or gas ), in pipeings, systems and in machinery.

Performance engine preparation Engine realities Production engines used as a base Designed for WOT 10% of the time RPM limits & improved components are.

© 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 Camshaft and Valve Train Service. 18 Camshaft and Valve Train Service.

Engine Components • Four-Stroke Cycle Engines • Engine Output

Engine Construction and Principles of Operation

Four Stroke Cycle Valve Operation. This figure shows typical valves for a four stroke engine These valves operate by means of a gear-and- cam arrangement.

Small Engine Troubleshooting Colquitt County Young Farmers August 31, 2006 Edited by CTAE Resource Network February 2011.

Basic Engine Operation & Construction

CHAPTER 10 The Valve Train Classroom Manual Page 243 Lab Manual

Engine: Top End Construction. Valve Covers - contains oil being splashed around valve galley - allows easy access for inspection and top end adjustment.

Engine Compression Theory. Four stroke cycle (gasoline engine) u Intake stroke –Piston going down - intake valve open. –Low pressure area is created in.

Two & Four Cycle Engines page 77 Questions on pg 90

The Valve Train Camshafts, Rocker Arms and Push Rods Presented By - David Smith.

Troubleshooting Small Engine Systems Jason Spurlin 4/10/02 Virginia Tech Edited by the CTAE Resource Network February 2011.

Valve Types, Valve Trains,

Introduction to the Engine

+ The Four Stroke Cycle By Elizabeth Fahey. + Outline Time Required: 1-3 classes Grades: 9-12 Background: Lesson is in conjunction with the small engine.

Chapter 4 Compression System

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Refers to the cylinder heads, valves, camshaft, and related components.

Resurfacing Heads & Blocks To restore gasket sealing & flatness Surface damage from: Corrosion around water passages Combustion gases Improper handling.

Engines Internal combustion engine needs

Flow through Valves Breathing abilities are limited by Smallest Areas of Flow …. P M V Subbarao Professor Mechanical Engineering Department.

Automotive Engines: Theory and Servicing, 7/e By James D. Halderman Copyright © 2011, 2009, 2005, 2001, 1997 Pearson Education, Inc., Upper Saddle River,

Compression Is an adiabatic process. This means heat is derived from the process. As we squeeze the air fuel mixture it gets hot. Normal compression ratio.

Engine Technology Engine Diagnostic its requires an understanding of the fundamentals & a systematic approach to determine what the problem is. If the.

Design of Engine Valves An Extended /Applied Fluid Mechanics…. P M V Subbarao Professor Mechanical Engineering Department.

Carburetion  Principles and Types The following lesson plan is courtsey of Virginia Tech University Agricultural Education, author unknown. It is reprinted.

Objectives Explain the basic function of an internal combustion engine. Describe the five events required for internal combustion engine operation. Describe.

IDENTIFY THE MAJOR SYSTEMS OF AN ENGINE!. NEXT GENERATION SCIENCE/COMMON CORE STANDARDS ADDRESSED! CCSS.ELA Literacy.RST.9‐ 10.3 Follow precisely a complex.

13 Engine Top End Construction Chapter Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives After studying.

Constructional Engine Components

Valve Train Assemblies

Automotive Engines Theory and Servicing

STEP ONE: INTAKE Air and fuel enter the small engine through the carburetor. The carburetor to supply a mixture of air and fuel for proper combustion.

Automotive Engines Theory and Servicing

Automotive Engines Theory and Servicing

OBJECTIVES State the principles of vacuum and the vacuum booster theory. Discuss how a vacuum brake booster operates. Discuss the vacuum booster operation.

How Many Small Engines do you have at home?

Engine Design and Classification

Internal Combustion Engine

Pistons, Rings, and Connecting Rods

Chapter 11 Lesson 3 Engine Top End.

Air Flow Management in Automotive Prime Movers

Engine Top End Construction

Four Stroke Engine Operation

Automotive Technology Principles, Diagnosis, and Service

Automotive Engines Theory and Servicing

Automotive Technology Principles, Diagnosis, and Service

Presentation transcript:

Small Engine Valves Prepared by: Brian D. Alexander Virginia Tech Edited by CTAE Resource Network February 2011

What do a Heart and an Engine have in common?

They both contain Valves! This unit will cover valves, valve trains, and the effect they have on compression.

Valves and Compression Performance Objectives: 1. Describe the valve parts of a small engines. 2. Explain the function of valves in an engine.

Valves and Compression Enabling Objectives: 1. Identify three types of valve systems. 2. Describe the function valves serve. 3. Identify the components of a poppet valve train. 4. Differentiate between intake and exhaust valves. 5. List the advantages of Over Head Valve systems. 6. List and identify six different valve problems. 7. List ways valves affect compression.

Purpose of Engine Valves Intake valve - a valve that permits a fluid or gas to enter a chamber and seals against exit. Exhaust valve - a valve that permits burned and unburned gases to escape, and seals against exit.

Valve Systems Poppet valves Overhead valves (OHV) Reed Valves

Poppet Valve Assembly Valve Valve spring Retainer(s)

Components of a Complete Valve Train Valve Valve guide Spring Cam

Overhead Valve System Improves volumetric efficiency. Eliminates combustion chamber hot-spots. Increases fuel efficiency by as much as 25%. Improves engine service life.

Valves Affect Compression It is essential that valve springs meet manufacturer specifications. Through overheating and extensive use, valve springs can lose their elasticity and become distorted.

Reed Valve System The reed valve system can be found in 2-cycle engines. Reed valve - a flat, flexible plate that permits air or liquid to pass in one direction but seals when the flow reverses.

Valve Operating Conditions °F High pressure pounds/sq. inch Open and close - 1/50 of a second (at 3000 RPM)

Inspecting Valves & Seats 1) Eroded, cracked, or pitted valve faces, heads, or stems 2) Warped head 3) Worn or improperly ground valve stems 4) Bent valve stems 5) Margin less than 1/64 inches 6) Partial seating

Valves Affect Compression The correct valve seat angle is necessary for proper valve seating. Valve seats are generally cut to a 45° angle, although 30° seat angles are used in a few engines. The value seat width is important for effective valve system operation. Valve seat widths range from in. (1/32 - 1/16 in.)

Valves Affect Compression It is essential that valve springs meet manufacturer specifications. Through overheating and extensive use, valve springs can lose their elasticity and become distorted.

Valves Affect Compression Valve guides align and “steer” the valves so that they can open fully and close completely. Valve-to-guide clearance should run about in.

Valves Affect Compression There are two types of valve guides –Bored in block –Pressed in block

Valve Failures

Summary Engine valves are essential Control intake and exhaust Affect compression Three major systems  Poppet  OHV  Reed