Fuel Economy Measurement in Small Commercial Vehicles with Sub 1L BS6 Diesel Engines an Innovative Approach to Accurately Measure Fuel Economy

In developing countries, the commercial vehicle industry is one of the key drivers for economic growth. The commercial vehicle industry in India is expected to reach 11,80,000 units by 2025 with a CAGR of 18% from CY 2020 to CY 2025 [1]. In the price sensitive segment of small commercial vehicles, it is imperative to incorporate accurate fuel economy measurement techniques during product development stage to deliver maximum value to the customer. In this approach, measuring the fuel consumption of small commercial vehicles in real world driving conditions in real time is one of the most critical aspects in engine calibration development and fine tuning. One of the challenges in measuring fuel consumption in sub 1 liter diesel engines is the very low fuel flow rate in the fuel feed line which keeps varying as per the driver demand. This paper presents a methodology of using fuel flow meters without tapping the vehicle’s regular fuel flow line which facilitate real time fuel flow metering values without affecting the drivability of the vehicle. Fuel flow meter data is recorded along with other critical engine parameters. The recorded fuel consumption data is validated against gravimetric fuel flow measurement and emission carbon balance method in chassis dynamometer and by gravimetric weight measurement method as per SAE J1526 ^TM for on-road measurements. The results show good correlation with R-squared value ranging between 0.97 to 0.98 between fuel economy measured using flow meter and gravimetric method as per SAE J1526^TM. The quality and consistency of correlation is established and verified across 2 different platforms. This paper explains in detail, the approach of instrumentation along with key results. This robust methodology provides repeatable & reproducible results consistently during on-road fuel economy development.