P10221: Baja 1 (Baja Driveline Test Development)

Drive Concept Generation & Selection

Table of Contents

Step 1. Clarify The Task

The team needs to connect the M.E. Dyno Lab Siemen's DC Motor output shaft with the output shaft of the Briggs & Stratton Model 20 10hp engine mounted on our engine stand. This needs to be done with regards to the following parameters:

  1. Capacity to operate both within the dyno sweet spot and the Briggs dynamic range.
  2. Ability for drive to allow engine tilt from -30 degrees to +30 degrees
  3. Easy & quick set-up/take down
  4. Withstand vibrations
  5. Affordable
  6. Safe

Step 2. Concept Generation

The team started by coming up with the following five drive-line connection methods which are ranked in the Pugh's matrix below.

public/Chain pulley gearbox.jpg

Drive Line Matrix

Drive Line Matrix

After narrowing down the high level drive-line concepts to: modifying the existing chain, a new chain system, or a new timing belt system, the team worked hard designing, specifying, and pricing each option to reflect the path of each drive-line concept. This allowed better comparison of the pros, cons, and cost of each of the three options. This can be seen below.

Drive Options Spec's/Cost

Drive Options Spec's/Cost

After laying the detailed options out on the table, the team conducted another Pugh's matrix, but this time with weighting of the selection criteria. In this case the timing belt system was used as the baseline since it appeared to be preferred by the customer. This Matrix can be seen below.

Top Three Drive Options Matrix

Top Three Drive Options Matrix

Step 3. Concept Selection

After several group meetings and another meeting with the customer, the decision was finally made to go ahead with Option 2, a modification of the existing 525 chain architecture. The team believes that the minor benefits of the timing belt/pulley system were not worth the major system cost increase associated. Although the customer showed preference toward the pulley system, our team sold the customer on the positives of modifying the existing chain drive:

Step 4. Improvements - Adding More Safety

Safety of a chain system was an initial concern brought up by both advisers and the customer in our design review. To combat this, and answer concerns surrounding the scenario of an extreme overload from the Dyno or an engine failure resulting in the Briggs seizing, we have taken steps with both our mechanical and electronic systems as follows:

public/Safety Hub.jpg

public/Test Fixture.jpg

public/Chain Guard.jpg

Step 5. Results Overview

Our final drive line design decisions thus far are shown below.

Chosen Drive-Line

Chosen Drive-Line

Step 6. Finalize & Order

To see the feasibility of the drive, please follow this link: Engineering Analysis

Here is the Bill of Material for drive components: public/BOM Drive.jpg

Step 7. Progress


Please check back for updates.