Professional engineering exam review machinery management
This presentation is the property of its rightful owner.
Sponsored Links
1 / 100

Professional Engineering Exam Review Machinery Management PowerPoint PPT Presentation


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

Professional Engineering Exam Review Machinery Management. Gary Roberson. Topics for Discussion. Implement performance Draft and power estimation Fuel consumption Machine capacity. Documents to Review.

Download Presentation

Professional Engineering Exam Review Machinery Management

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


Professional engineering exam review machinery management

Professional Engineering Exam ReviewMachinery Management

Gary Roberson


Topics for discussion

Topics for Discussion

  • Implement performance

  • Draft and power estimation

  • Fuel consumption

  • Machine capacity


Documents to review

Documents to Review

  • ASAE S296.5 (DEC2003) General Terminology for Traction of Agricultural Traction and Transport Devices and Vehicles

    • terminology to assist in the standardized reporting of information on traction and transport devices and vehicles.


Documents to review1

Documents to Review

  • ASAE S495.1 (NOV2005) Uniform Terminology for Agricultural Machinery Management

    • Uniform use of machinery management terms.

    • Definitions used in system analysis, economic analysis, and mechanical concepts.


Documents to review2

Documents to Review

  • ASAE EP496.3 (FEB2006)Agricultural Machinery Management

    • Management decisions related to machine power requirements, capacities, cost, selection and replacement


Documents to review3

Documents to Review

  • ASAE D497.6 (JUN2009) Agricultural Machinery Management Data

    • Data for use with decision tools from ASAE EP496.3


Books of interest

Books of Interest

  • Machinery Management, W. Bowers, Deere and Co.

  • Farm Power and Machinery Management, D. Hunt, Iowa State University Press.

  • Engineering Principles of Agricultural Machines, A. Srivastava, et al , ASABE

  • Engineering Models for Agricultural Production, D. Hunt, AVI Publishing Co.

  • Agricultural Systems Management, R. Peart and W. Shoup, Marcel Dekker


Implement power requirement

Implement Power Requirement

  • Drawbar power

    • Power developed by the drive wheels or tracks and transmitted through the hitch or drawbar to move the implement.

    • Power is the result of draft (force) and speed


Implement draft

Implement Draft

  • D is implement draft, N (lbf)

  • Rsc is soil and crop resistance, N (lbf)

  • MR is total implement motion resistance, N (lbf)


Implement draft1

Implement Draft

Where:

  • D=draft, N (lbf)

  • F=soil texture parameter

  • i=texture indicator:

    • 1=fine, 2=medium, 3=coarse

  • A, B, And C = machine parameters (Table 1, D497)

  • S=speed, km/h (mph)

  • W=width, m (ft) or number of tools

  • T=tillage depth, cm (in),

    • (1 for tools that are not depth specific)


Implement draft example

Implement Draft Example

  • A 12 foot wide chisel plow with straight points and shanks spaced 1 foot apart is used at a depth of 6 inches in medium textured soil at a speed of 5 mph.


Table 1 d497 5

Table 1, D497.5


Implement draft example1

Implement Draft Example

  • Chisel plow with straight points

    • Table 1 in D497.5

      • A = 52, B = 4.9, and C = 0

  • Medium soil texture

    • Table 1 in D497.5

      • F2 = .85

  • S = 5 mph

  • W = 12 ft or 12 tools

  • T = 6 in


Implement draft example2

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT


Implement draft example3

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[52+4.9(5)]12x6


Implement draft example4

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[52+4.9(5)]12x6

  • D= ?


Implement draft example5

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[52+4.9(5)]12x6

  • D= 4682 lbf


Implement draft example6

Implement Draft Example

  • A 12 shank chisel plow with straight points and shanks spaced 0.3 meters apart is used at a depth of 0.15 meters in medium textured soil at a speed of 8 km/hr.


Table 1 d497 51

Table 1, D497.5


Implement draft example7

Implement Draft Example

  • Chisel plow with straight points

    • Table 1 in D497.5

      • A = 91, B = 5.4, and C = 0

  • Medium soil texture

    • Table 1 in D497.5

      • F2 = .85

  • S = 8 km/hr

  • W = 12 shanks

  • T = 0.15 meters = 15 cm


Implement draft example8

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT


Implement draft example9

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[91+5.4(8)]12x15


Implement draft example10

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[91+5.4(8)]12x15

  • D= ?


Implement draft example11

Implement Draft Example

  • D=Fi[A+B(S)+C(S)2]WT

  • D=0.85x[91+5.4(8)]12x15

  • D= 20,533 N


Implement draft exercise

Implement Draft Exercise

  • A 4 shank subsoiler with straight points is used at a depth of 16 inches in coarse textured soil at a speed of 4 mph.

  • What’s the Draft?


Table 1 d497 52

Table 1, D497.5


Implement draft exercise1

Implement Draft Exercise

  • A 4 shank subsoiler with straight points is used at a depth of 16 inches in coarse textured soil at a speed of 4 mph.

  • What’s the Draft?

    4959 LB


Implement draft exercise2

Implement Draft Exercise

  • A 4 shank subsoiler with straight points is used at a depth of 0.41 meters in coarse textured soil at a speed of 6.5 km/hr.

  • What’s the Draft?


Table 1 d497 53

Table 1, D497.5


Implement draft exercise3

Implement Draft Exercise

  • A 4 shank subsoiler with straight points is used at a depth of 0.41 meters in coarse textured soil at a speed of 6.5 km/hr.

  • What’s the Draft?

    22,291 N


Drawbar power

Drawbar Power

  • Pdb = Drawbar Power, HP

  • D = Draft, lbf

  • S = Speed, mph


Drawbar power1

Drawbar Power

  • Pdb = Drawbar Power, kW

  • D = Draft, kN

  • S = Speed, km/hr


Drawbar power example

Drawbar Power Example

An Implement with a draft of 8,500 lbf is operated at a net or true ground speed of 5.0 MPH with 10 percent wheel slippage. What is the implement drawbar power?


Drawbar power2

Drawbar Power


Drawbar power3

Drawbar Power


Pto power

PTO Power

  • PTO power is required from some implements and is delivered through the tractor PTO via a driveline to the implement.

  • The rotary power requirement is a function of the size and feed rate of the implement.


Pto power1

PTO Power

  • Ppto = PTO power

  • W = implement working width, ft

  • F = material feed rate. t/hr


Table 2 d497 5

Table 2, D497.5

kWh/t

kW

kW/m


Pto power example

PTO Power Example

  • A large round baler has a capacity of 10 tons per hour. The baler has a variable bale chamber


Table 2 d497 51

Table 2, D497.5


Implement pto example

Implement PTO Example

  • Variable Chamber Round Baler

    • Table 2 in D497.5

      • A = 5.4, B = 0, and C = 1.3

    • 10 t/hr capacity


Implement pto example1

Implement PTO Example


Implement pto example2

Implement PTO Example


Implement pto example3

Implement PTO Example


Pto power exercise

PTO Power Exercise

  • A rectangular baler has a capacity of 3 tons per hour. Bale dimensions (cross section) are 16” x 18”.

  • What’s the PTO power requirement?


Table 2 d497 52

Table 2, D497.5


Pto power exercise1

PTO Power Exercise

  • A rectangular baler has a capacity of 3 tons per hour. Bale dimensions (cross section) are 16” x 18”.

  • What’s the PTO power requirement?


Pto power exercise2

PTO Power Exercise

  • A rectangular baler has a capacity of 3 tons per hour. Bale dimensions (cross section) are 16” x 18”.

  • What’s the PTO power requirement?

    6.3 Hp


Hydraulic power

Hydraulic Power

  • Fluid power requirement from the tractor for the implement

  • Hydraulic motors and cylinders used to drive implement functions


Hydraulic power1

Hydraulic Power

  • Phyd = fluid power, HP

  • P = fluid pressure, psi

  • F = fluid flow, gpm


Hydraulic power2

Hydraulic Power

  • Phyd = fluid power, kW

  • P = fluid pressure, kPa

  • F = fluid flow, L/s


Hydraulic power example

Hydraulic Power Example

  • A harvester uses hydraulic power to drive a conveyor. The requirements were measured at 10.5 gpm at a pressure of 2200 PSI.


Hydraulic power3

Hydraulic Power


Hydraulic power4

Hydraulic Power


Hydraulic power5

Hydraulic Power


Electrical power

Electrical Power

  • Some implements require electrical power supplied by the tractor for certain functions.

    • Typically electrical power for control functions is small and can be neglected.

    • Electrical power for pumps and motors should be accounted for.


Electrical power1

Electrical Power

  • Pel = Electrical Power, HP

  • I = electrical Current, A

  • E = Electrical potential (voltage), V


Electrical power2

Electrical Power

  • Pel = Electrical Power, kW

  • I = electrical Current, A

  • E = Electrical potential (voltage), V


Electrical power example

Electrical Power Example

  • A sprayer uses electrical power to drive a pump. The requirements were measured at 20 amps at 12 volts.


Electrical power3

Electrical Power


Electrical power4

Electrical Power


Electrical power5

Electrical Power


Implement power

Implement Power

  • Combined total of drawbar, PTO, Hydraulic and Electrical power

    • Drawbar power adjusted by tractive and mechanical efficiencies

  • 80% rule

    • Implement power should not exceed 80% of rated tractor power


Tractive efficiency

Tractive Efficiency

  • Ratio of drawbar power to axle power

  • Takes into account the added resistance the tractor will encounter in moving through the soil.

    • Firmer soil, higher TE

    • Softer soil, lower TE


Mechanical efficiency

Mechanical Efficiency

  • Accounts for power losses in the tractor drive train.

    • Accounts for friction loss, slippage in a clutch, torque converters, etc.

  • Usually constant for a given tractor

    • Typically 0.96 for tractors with mechanical transmissions

    • 0.80 to 0.90 for hydrostatic transmissions


Power efficiency chart

Power Efficiency Chart


Implement power1

Implement Power

  • Pt = total power, HP

  • Pdb = drawbar power, HP

  • Em = mechanical efficiency

  • Et = tractive efficiency

  • Ppto = PTO power, HP

  • Phyd = Hydraulic power, HP

  • Pel = electrical power, HP


Implement power problem

Implement Power Problem

  • Determine the recommended tractor size for an implement that requires 48 drawbar horsepower, 12 PTO horsepower and 2.5 hydraulic horsepower. The tractor should be 2 wheel drive with a mechanical transmission and you will operate on a tilled soil surface.


Power efficiency chart1

Power Efficiency Chart


Drawbar power conditions

Drawbar Power Conditions

  • Determine the tractive efficiency anticipated.

    • From Figure 1, D497.5

      • 2WD on tilled soil surface, TE = 0.67

  • Assume a mechanical efficiency of 0.96


Implement power2

Implement Power


Implement power3

Implement Power


Implement power4

Implement Power


Tractor size

Tractor Size

  • Determine the implement power requirement

  • Apply the 80 % rule

  • Example:

    • Implement power = 89.1 HP

    • Tractor power = 89.1/.8 = 111.4 HP


Tractor size exercise

Tractor Size Exercise

  • An implement uses 25 PTO horsepower, 3.6 horsepower through the hydraulic system and 1.9 horsepower in the electrical system. What is the minimum recommended tractor size?


Tractor size exercise1

Tractor Size Exercise

  • An implement uses 25 PTO horsepower, 3.6 horsepower through the hydraulic system and 1.9 horsepower in the electrical system. What is the minimum recommended tractor size?

    38.1 Hp


Tractor fuel consumption

Tractor Fuel Consumption

  • Fuel consumption can be estimated for tractors used in various operations.

    • Specific fuel consumption is quoted in units of gal/hp-hr

  • Average fuel Consumption (Diesel)

    • Qs = 0.52X + 0.77 - 0.04(738X + 173)1/2

    • where X = ratio of equivalent PTO power to rated tractor power


Tractor fuel consumption example

Tractor Fuel Consumption Example

  • A 95 PTO horsepower tractor is used with a 55 horsepower load. How much fuel will be consumed in one day (10 hours)?

    • X = 55/95 = 0.58

  • Qs = 0.52x0.58 + 0.77 -

    0.04((738 x 0.58) + 173)1/2

    Qs = 0.092 gal/hp-hr


Tractor fuel consumption example1

Tractor Fuel Consumption Example

  • Estimated Fuel Consumption

    • Qi = Qs x Pt

    • Qi = 0.092 x 55

    • Qi = 5.06 gal/hr

  • Total Fuel Consumption

    • 5.06 gal/hr x 10 hrs = 50.6 gal


Equipment economics

Equipment Economics

  • Required Capacity

    • Size of machine necessary to get the job done in the time available.

      • Acres/Hour

  • Effective Capacity

    • Available capacity of equipment in operation

      • Acres/Hour


Machine capacity

Machine Capacity

  • Required capacity will tell you how large the machine should be

  • Effective capacity will tell you what a given piece of equipment can deliver

  • Effective capacity should equal or exceed required capacity for most applications


Machine capacity1

Machine Capacity

  • Ci = required capacity, ac/hr

  • A = Area to be covered, ac

  • B = days available

  • G = working hours per day

  • PWD = probability of a day suitable for field work in the given time frame


Machine capacity example

Machine Capacity Example

  • What size machine is needed to cover 1000 acres in a three week (5 days per week) window in August in North Carolina. You can work up to 10 hours per day.

  • From Table 5. D497.5

    • PWD = 0.51


Machine capacity2

Machine Capacity


Machine capacity3

Machine Capacity


Machine capacity4

Machine Capacity

  • Ca = available capacity, ac/hr

  • S = speed, mph

  • W = width, ft

  • Ef = Field Efficiency


Field efficiency

Field Efficiency

  • Ratio of effective field capacity to theoretical field capacity

  • Effective field capacity is the actual rate at which an operation is performed

  • Theoretical field capacity is the rate which could be achieved if a machine operated 100% of the time available at the required speed and used 100% of its theoretical width


Theoretical vs effective width

Theoretical vs. Effective Width

  • Theoretical width

    • Measured width of the working portion of a machine

      • For row crops, it is row spacing times number of rows

  • Effective width

    • Actual machine working width, may be more or less than the theoretical width


Field efficiency and speed

Field Efficiency and Speed


Machine capacity example1

Machine Capacity Example

  • What is the capacity of disc harrow that operates at 6 mph with a working width of 18 ft?

  • From Table 3. D497.5

    • Typical field efficiency is 80% (0.80)


Machine capacity example2

Machine Capacity Example


Machine capacity example3

Machine Capacity Example


Machine capacity exercise

Machine Capacity Exercise

You are given an implement that covers 8 rows on a 36 inch row spacing. This implement is effective at 6 miles per hour with a field efficiency of 80%.

You have a 2 week window working 5 days a week, 10 hours per day. Probability of a working day is 60%. You have 500 acres to cover.

Is this implement large enough to get the job done?


Machine capacity exercise1

Machine Capacity Exercise

You are given an implement that covers 8 rows on a 36 inch row spacing. This implement is effective at 6 miles per hour with a field efficiency of 80%.


Machine capacity exercise2

Machine Capacity Exercise

You have a 2 week window working 5 days a week, 10 hours per day. Probability of a working day is 60%. You have 500 acres to cover.


Machine capacity exercise3

Machine Capacity Exercise

Is this implement large enough to get the job done?

Available Capacity > Required Capacity

13.96 ac/hr > 8.33 ac/hr

Yes, the implement is large enough.


Professional engineering exam review machinery management

Questions?


General problem solving guides

General Problem Solving Guides

  • Study the problem

  • Determine the critical information

  • Decide on a solution method or equation

  • State all assumptions, cite data sources

  • Solve the problem

  • Indicate solution clearly


Contact information

Contact Information

Gary Roberson

Associate Professor and Extension Specialist

Biological and Agricultural Engineering

North Carolina State University

E-mail: [email protected]

Phone: 919-515-6715

Good Luck!


  • Login