Fleets across various industries increasingly prioritize fuel economy improvements as part of their sustainability initiatives. However, selecting the most appropriate fuel economy test is crucial to making informed decisions about technology investments. Several testing methods are available, each with its advantages and limitations. Understanding these methods enables fleets to choose the most suitable one for their specific requirements.
SAE J1321 Type II Testing
One widely used method is the SAE (Society of Automotive Engineers) J1321 Type II Testing protocol. This comparison study involves actual vehicles and assesses results by weighing fuel tanks before and after the test, presenting a percentage change. Two fleet vehicles undergo dedicated tests on a track or highway, evaluating various elements such as aerodynamic devices, tires, lubricants, fuel treatment/devices, gear ratios, air intake technologies, engines, and transmissions.
Fleets can conduct these tests themselves by purchasing testing equipment and training employees, or they can opt for outsourcing, albeit at a higher cost. However, accuracy has been a concern, with a potential margin of error of ± 5.0%, emphasizing the importance of calculating the margin of error when evaluating test results.
Pros of SAE J1321 Type II Testing:
- Fleet autonomy to conduct tests with acquired equipment and suitable locations.
- Quick results within one or two days using real fleet vehicles.
- Low-cost potential if conducted internally, albeit higher expenses if outsourced.
Cons of SAE J1321 Type II Testing:
- Potential accuracy issues, especially if conducted by untrained personnel.
- Results lack verifiability and cannot provide precise fleet savings values.
- Inability to ascertain actual fuel savings.
Wind Tunnel Tests
Wind tunnel tests focus primarily on aerodynamics, employing scale models to simulate highway driving conditions. However, these tests do not measure fuel savings directly but estimate them based on the achieved drag coefficient. Yet, this estimation lacks weight, terrain, and driving behavior accuracy.
Pros of Wind Tunnel Tests:
- Quick adjustments to vehicle configurations.
- Cost-effective for hired testing.
- Swift changes compared to on-track testing.
Cons of Wind Tunnel Tests:
- Limited to aerodynamics and scale models that might not match fleet vehicles.
- Inability to measure actual fuel savings directly.
- Possibility of requiring custom scale model parts.
Computational Fluid Dynamics (CFD) Tests
CFD tests are computer simulations that analyze simulated aerodynamic drag, offering insights into airflow across the vehicle. However, like wind tunnel results, CFD measures only aerodynamic drag, requiring a 50% multiplication factor to estimate fuel savings. The accuracy heavily relies on the operator’s inputs.
Pros of CFD Tests:
- Quick insights and adjustments.
- Real vehicles are not required.
- Cost-effective for hired testing.
Cons of CFD Tests:
- Limited to aerodynamics.
- Dependence on operator inputs for accuracy.
- Inability to measure actual fuel saved directly.
Coast-Down Tests
Coast-down tests analyze changes in vehicle speed while coasting with and without specific technologies. These tests primarily measure aerodynamics and tire rolling resistance, requiring specialized equipment and focusing solely on certain aspects of vehicle performance.
Pros of Coast-Down Tests:
- Fleet autonomy to conduct tests.
- Quick results using real fleet vehicles.
- Low internal testing costs.
Cons of Coast-Down Tests:
- Limited to aerodynamics and tire testing.
- Inability to measure actual fuel savings directly.
- The necessity of purchasing and learning specialized equipment.
In-Service Fleet Tests
In-service fleet tests involve monitoring similar trucks on similar routes comparing performance with and without specific technologies. Despite providing real-life data, these tests require long durations (6 to 12 months) and substantial labor.
Pros of In-Service Fleet Tests:
- Accurate data relevant to fleet operations.
- Measures actual fleet fuel savings.
- Allows testing various technologies.
Cons of In-Service Fleet Tests:
- Lengthy duration for results.
- Significant sample size and investment are required.
- High labor involvement and potential complications.
MVT Solutions Tests
MVT Solutions tests use real vehicles, measuring fuel saved while testing various technologies on tracks or highways. These tests provide highly accurate results, albeit requiring MVT Solutions equipment and personnel involvement.
Pros of MVT Solutions Tests:
- Same-day results with high accuracy.
- Provides actual fleet savings values.
- Low complication compared to in-service testing.
Cons of MVT Solutions Tests:
- Reliance on MVT Solutions equipment and personnel.
- Some vehicle downtime and scheduling constraints.
Conclusion
Selecting the right fuel economy test for your fleet necessitates careful consideration of test capabilities and limitations. There’s no perfect test, and each method presents trade-offs. Seeking expert advice, checking track records, and potentially using multiple test methods can provide a more comprehensive understanding of fleet fuel economy. Remember, taking no action guarantees wasted fuel, profits, and increased emissions.
