Driveability? or Drivability? Either way you spell it…Key objective metrics define it.

ETAS has developed a driveability tool which provides efficient, consistent analysis and reporting of key objective metrics.  The Engine Driveability Toolbox (EDT) and Transmission Driveability Toolbox (TDT) are available as part of INCA-FLOW.

Reaching an agreement to the correct spelling of Driveability is as difficult as an agreement to its definition. Driveability can mean different things either to the end user, powertrain engineer, chassis control engineer, or vehicle platform team. For this post, let’s limit the scope to the powertrain, in particular to two major transmission metrics:  shift quality (comfort, jerk) and performance (acceleration, time). The powertrain engineer often tries to find the right balance between these two major metrics as depicted below.

Figure 1 .  Shift performance and Shift Quality Trade-offs

Driveability is the consumer perception of the vehicle. How well the vehicle responds (movement, sound) to the driver expectations affects the driver’s emotion and opinions of how well the car drives.  The driver has few inputs to the vehicle to convey their intentions: Accelerator Pedal, Brake Pedal, Steering Wheel, and Transmission Mode. A group of drivers would have different expectations and give different subjective ratings on the shift quality and shift performance for the same vehicle.

Driveability is the physical response to the driver inputs. Objective, physics based performance metrics, such as time and acceleration, are transferable when the same methods are used for measurement. This requires a tool with standardized definitions of events such as INCA-FLOW EDT and TDT.

Driveability is important for business success. Much of the advertising for cars highlights the experience and emotion of the vehicle use. Brand or DNA differentiation among models and competitors may be achieved by unique tuning of drivetrain features for the market segment. Driveability development with good tools and processes yields a positive experience for the user and avoids legal, financial, societal, and quality issues for new product launches.

Driveability development continues with the added complexity of hybrid configurations and electrification of transmissions to improve fuel efficiency. Battery Electric or Plug-in Electric vehicles still need to perform to the driver’s expectations across a range of battery charge state and temperatures. Future electric vehicles may also transition from single gear transmissions to multiple gear transmissions to achieve range, cost and performance goals.

Driveability Toolbox (EDT)

EDT is useful for in-vehicle development. EDT measured and calculated metrics can be imported, displayed, and recorded in the calibration environment.

INCA FLOW EDT INCA live
Figure 2. EDT parameters live run-time in INCA

For High Resolution Video Click Here

Transmission Driveability Toolbox (TDT)

TDT is useful to quickly post-process shift event data. The data is organized by events and plotted automatically. This is very useful for efficient analysis and sharing results and status.

INCA FLOW TDT
Figure 3. Analysis and Report with Transmission Driveability Toolbox (TDT)

For High Resolution Video Click Here (Part 1)

For High Resolution Video Click Here (Part 2)

Groups calibrating and evaluating Powertrain Systems (Engine, E-Motor, Transmission) to achieve Driveability and NVH characteristics would benefit using ETAS INCA FLOW with the Engine Driveability Toolbox (EDT) and Transmission Driveability Toolbox (TDT).

An efficient tool set for Teams within OEMs and Tier-1 such as:

  • Vehicle Platform team
  • Ride Quality Assessment
  • Competitive Analysis / Benchmarking
  • Powertrain integration
  • Engine torque calibration
  • Transmission shift scheduling and shift event calibration

If you have any questions, just comment below. For more information or if you’d like to see a live demo, please contact me.

 

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