Objectives Using TRIZ in Project-Based-Learning „ To search effective methods to teach invention to students. Assisted by CAE and invention to students. „ To improve project-based-learning Manufacturing Experiences curriculum by using TRIZ.

Masao Ishihama Kanagawa Institute of Technology

What is the “Formula SAE”?

„ Purpose： Engineering education CASE STUDY No.1: „ Organizer： SAE (Society of Automotive Engineers) EngineEngine IntakeIntake SystemSystem „ Venue: Michigan, U.S.A. „ Time: May, every year since 1989 Design for Formula SAE „ Participants: 140 Universities Racing Car Development World wide Student Competition „ Sponsor: Big3 and major Auto companies. How the participants are evaluated? Position of this project in our

„ Full marks: 1,000 points. education „ Static Event Competition; 350 points Static Event Competition; 350 „ A regular subject at our Vehicle Product concept presentation Engineering Department Design judge (Technological aspect) Design judge (Technological aspect) „ Project based learning Cost analysis ≤≈$30,000 3,300,000Yen „ Consists of lecture series, design „ Dynamic Event Competition; 650 points reviews, laboratory works, fund Standing start acceleration raising, public relations, tours, etc. Turning on a skid pad „ Students: Any student (from Time trial on an auto-cross course freshmen to seniors) Endurance and fuel economy run

What the students can learn Our student team record

„ Skill of integrating fundamental knowledge in many disciplines. „ Formula SAE tour th st „ Grasp the idea of whole engineering 25 place in 2004. (1 in fuel economy) process, i.e. product planning, concept Retired in 2005 generation, design, CAE, prototyping, 27th place in 2006 testing, etc. „ Formula Japan „ Team work. 2nd place in 2004 „ Presentation skill. nd „ Direct contact with industry and 2 place in 2005 engineers. Base engine specifications Required engine performance

„ Lower speed range „ Quick response because of the racing track „ Honda CBR600F4i （600cc） because of the racing track design and drivers’ skill. „ In-line 4, DOHC 16-valves „ Electronic fuel injection control „ Power: 72 PS / 12,000 rpm „ Torque: 38 ft-lb / 10,000rpm

Elements of a Typical F-SAE A simplified model track Racing Track for test runs Slalom Slalom zone High-speed Hair-pin corner corner

Hair-pin corner

High-speed corner Engine speed distribution Restrictions on the engine design on the simplified model track Frequently used speed range „ Piston displacement < 0.61 liters. „ An air flow restrictor ( φ 20mm) must be placed. „ The complete air intake system must lie within a specified space. Frequency, %

Engine speed, rpm

Design principle and Inertia effect Embodiment design 1. Intake valve opens

Negative pressure travels upstream „ Physical principle for realizing performance; 2.Piston sucks air “Intake air inertia effect” 1st Step: Intake and exhaust system Positive pressure travels parametrical optimization by CAE. downstream 2nd Step: Embodiment design that lead 3. Intake valve shuts to contradictions. Air column keeps flowing Dense air is charged. Intake pipe length tuning Collector volume tuning to use the inertia effect „ Must be small for quick response.

at low engine speed Can the two requirements be satisfied at the same time?

How long? „ Must be large for uniform air Does it within the space restriction? distribution.

Intake system performance Intake system performance Embodiment design simulation A. Collector design Quasi-one- dimensional Necessary functions of the collector: analysis model. • To minimize pressure drop Shapes of elements • To give uniform air flow distribution over all cannot be dealt cylinders. with. Strategy to realize the functions: • To slow down the air flow. „ Ignoring the space restrictions, suitable values • To avoid sharp corners. of intake pipe length and collector volume • To assure equal cross sectional area. were found for the performance requirements. • To give same shapes and bents to the flow „ The designer (student) was able to move to passage to each cylinder. embodiment design and invention quickly. Restrictions from Intake tube design manufacturability and safety. „ Flow velocity distribution in a computational fluid dynamics model. „ Casting is desirable for realizing free This model three dimensional shape. However, meets no foundry was available. performance „ Fiber-reinforced plastic is possible. requirements. However, safety under heat and gas However, it exposure was not clearly understood. occupies too A probable solution: large space. Build a collector into a cylindrical shape by sheet metal welding.

Contradictions

A) The intake tube must be long and InventionInvention byby ourour straight. B) The collector must have enough studentsstudents volume. C) The collector must give each cylinder equal air flow with minimum turbulence. D) Each component must be made with simple tools. E) Over all intake system must lie in a small space. Contradiction matrix Inventive principles induced in the intake design and specific ideas #7 Nesting: An object passes through Feature to change Undesired result principlea cavity of another object. Area of non-moving 17, 7, =>10, Inserting40 the intake tube deep object into the collector. Length of non- Volume of moving 35, 8, 2, 14 moving objedt object #14 Spheroidality: Replace flat surface force 28, 10 with curved surface. power 12, 8 => Hemispherical collector bulkhead to turn the airflow smoothly.

Inventive principles induced Realization of the inventive and specific ideas (continued) principle

„ Cross-section of the invented intake #17 Moving to a new dimension: Move system an object in a plane to three dimensional space. => designing three dimensional air flow in the collector with radial and rotational movement. Manufacturability Testing the invented intake system

„ Easy to build: Intake pipe: Lathing Collector shell: Sheet metal bending and welding. „ These methods of manufacturing were conceived by the student from the beginning of the invention. Cylinder no.1 Cylinder no.3 intake stroke intake stroke „ The student had plenty of hands-on experience of manufacturing. „ The streamlines are smooth for every cylinder intake stroke.

Project description

„ To give more mobility to people with CASE STUDY No.2: walking difficulties. „ To fill daily needs and to exercise, Walking aid for outdoors such as to go to a nearby post office, convenient stores, etc. „ Must run over rough surface and ride over gaps like motor vehicles, while giving small vibration and sure support to their users. Large diameter wheel makes Mechanics of gap over-ride climbing slope gentler.

To increase „ For 50mm gap pitch stability climbing, margin: 500mm diameter is F => small necessary. L => large „ 500mm wheel is too large for free leg movement

Requirement of shock isolation Contradictions

Large thrust Shock to grips „ Feature to change: Thrust force reduction. „ Undesired result: Large diameter wheel Instability due to soft suspension Invention principles Invention principles

„ Segmentation: To divide a large wheel into a number of small wheels „ Asymmetry: Use only the front part to form a large diameter envelope of the said envelope circle. circle.

Virtual large radius wheel by Invention principles Virtual large radius wheel by enveloping multi small wheels „ Prior action: Store energy in spring Pivot Caster mechanism beforehand and use it when the front wheel really climbs the gap. Torsion spring V shaped link This makes the waveform of thrust (swing arm) flatter . 揺 Peaky thrust curve 動 Store energy Leading wheel φ740 Gap climbing Virt Thrust, N ual larg e wh Travel distance, m eel Multi-body dynamics simulation Testing the idea of the front wheel motion Collision of the V-link main wheel V-link swing

Touch down of the leading wheel

50mm Energy „ With CAE simulation background, the accumulation in student inventor created a simulation the torsion spring model quickly. Energy release Animated bump override simulation and gap climbing

The front suspension gives 0.25 more gentle slope The prototype

Rigid axle

0.2 Torsion spring suspension Gentle slope

Energy storing time period Vertical displacement, m displacement, Vertical 0.15

0123Time, s Bump height = 50mm The powerassistperformance The powerassistperformance

Horizontal Force (Thrust),N the designspecification. Measured thrustvaluesatisfies With power assist Threshold, 128N Without power assist Time, s „ „ „ „ „ „ invention. has animportantroleinlearning and theirmanufacturingexperience aided engineering(CAE)software environment toteachTRIZ. Project basedlearningisagood Students students inventionwereacquired. Important lessonsinteaching invention. has animportantroleinlearning and theirmanufacturingexperience aided engineering(CAE)software environment toteachTRIZ. Project basedlearningisagood Students students inventionwereacquired. Important lessonsinteaching ’ ’ Conclusions Conclusions skill ofusingcomputer skill ofusingcomputer