Analysis of the Deviation Factors between the Actual and Test Fuel Economy

Masayoshi Tanishita,Takashi Kobayashi

doi:10.3390/vehicles3020010

Abstract

The Worldwide harmonized Light duty Test Procedure saw its light first as the United Nations Economic Commission for Europe Global Technical Regulation in 2017. However, it remains unclear how much the deviation is between the actual and test fuel economy. In this study, we analyzed the deviation between the actual and test (JC08 and WLTC) fuel economy and examined how well regional characteristics such as average travel speed and temperature could explain the deviation using 182–1035 drivers and 19–52 car models data in Japan. As a result, (1) more than a 30% discrepancy was observed between the actual and JC08 mode test fuel economy, and the higher the test fuel economy, the larger the deviation; (2) regarding WLTC mode fuel economy, the deviation is 19% and constant regardless of the test fuel economy; (3) average travel speed and temperature can explain approximately 8% of the discrepancy.

Highlights

Analysis of the Deviation FactorsThe fuel economy of passenger cars is shown at the time of sale based on the fuel economy test
Fuel economy tests are used for two primary purposes: (1) to monitor the compliance of automobile manufacturers with fuel economy and greenhouse gas emissions standards and (2) to inform consumers about the fuel economy of passenger cars and light trucks [1]
Many factors bring about the divergence between the test fuel economy, such as drivers, vehicle attributes, driving environment, and driver’s behavior

Summary

Introduction

The fuel economy of passenger cars is shown at the time of sale based on the fuel economy test. This is calculated from the relationship between the distance and fuel consumption based on the “test cycle” that defines the relationship between time and speed (acceleration) in the laboratory. It has been noted that there is a considerable discrepancy between the actual and test fuel economy This divergence can lead to errors in CO2 emissions reduction by policy interventions and can distort appropriate consumers’. Many factors bring about the divergence between the test fuel economy, such as drivers (hereafter, actual fuel economy), vehicle attributes (e.g., engine, accessories, hybrid system), driving environment (e.g., temperature, congestion level, pavements, vertical alignments), and driver’s behavior (e.g., acceleration, trip distance). It is practically impossible to collect actual fuel economy data in the laboratory

Methods

Results

Discussion

Conclusion