Group 12 - Leaf Blower

Executive Summary

The objective project was for our group, twelve, to look into the assembly, function, manufacturing, and materials of a leafblower. The leafblower is a common device used by lawn care companies and some household owners. We analyzed the product, disassembeled it while taking careful notes and then reassembled the leafblower. We took pictures for the disection processes, recorded the level of difficulty for each step and analyzed each part of the product with great detail. The group worked well together as a team to complete this goal.

GATE 1: REQUEST FOR PROPOSAL

The link below is a detailed description of our request for proposal that includes the following:

Purpose
Work Proposal
Time Management
Group Assesment
Management Proposal
Inititial Product Assesment
Functionality and Complexity
Alternatives

GATE 2: PRELIMINARY DESIGN REVIEW

The link below is a detailed description of our preliminary design review that includes the following:

Causes for Corrective Action
Product Dissection Plan

Engineering Analysis

Problem: Solve the analysis problem defined by my group members. Our problem was our spark plug fouled over time.

Assumptions:
• The magneto is working correctly.
• The circuit is completed when the spark plug is working correctly and allows electron flow.
• The spark plug is fouled to the degree to which it no longer allows electron flow.
• The amount of voltage needed by a spark plug to fire is 5000 Volts up to 10000 Volts.
• The minimum amount of ohms required to fire off a spark plug normally is 10 Ohms. At 0 Ohms the spark plug will not fire.

Governing equations:
V=I*R

Solution:
V = I * R => 5000 V = I * 10 ohm => I = 500 A
V = I * R => 10000 V = I * 10 ohm => I = 1000 A
V = I * R => 5000 V = I * 5 ohm => I = 1000 A
V = I * R => 10000 V = I * 5 ohm => I = 2000 A
V = I * R => 5000 V = I * 1 ohm => I = 5000 A
V = I * R => 10000 V = I * 1 ohm => I = 10000 A

Discussion:
From the calculations, the spark plug requires at most 1000 A to run normally. The spark plug has a varying range of voltages so at times even when the spark plug’s resistance is decaying the spark plug still has a chance to fire normally. However most of the time the lower resistances will have misfires and function abnormally. When the resistance drops to 0  then the spark plug does not have any energy to create a spark. This is not the only way that a spark plug can foul. More commonly, the spark plug can foul by having the gap grow to such a distance that a spark cannot be created, or the spark plug erodes, corrodes, or physically breaks to a point where it can no longer complete the circuit. When the damage is to that degree, electrons can no longer flow and create a spark.

Sources: The assumptions of voltage and Ohms were gathered from the website: http://www.jackssmallengines.com/reading_sparkplugs.cfm