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Measurement for Recovery
Case studies

Improving confidence in data models for real applications

NPL worked with EMTEC to assess their methodology for estimating carbon emissions from on-board diagnostics, and comparing to actual data.

The challenge

The EMTEC Corporation is a UK based start-up founded in July 2017, which aims to use data analytics to reduce transport-based emissions and pollution. They have developed a cloud-based platform that receives data from connected vehicles via smart devices, which can then be used to provide real-time analysis of vehicle performance and driver behaviour.

EMTEC asked NPL to provide an independent assessment of their carbon emissions algorithm for road vehicles, both petrol and diesel. The EMTEC model uses datasets from vehicle on-board diagnostics (OBD), and an analytical model to reflect different regimes of driving. The results of the model can be compared with direct measurements of carbon emissions from the Millbrook proving ground, a dedicated vehicle test environment.

 

The solution

Comparison of Millbrook measurements and EMTEC estimates.pngNPL carried out a critical assessment of the principles and assumptions used to derive the EMTEC model and reviewed the parameters used within the calculations. The NPL approach used a ‘ground truth’ test, where data from the EMTEC algorithm was compared with actual field test measurements from the Millbrook proving ground, which would in turn provide useful information and confidence in the algorithm.

A comparison was carried out between measured data via on-board diagnostics and predicted values via the EMTEC model. NPL assessed the validity of the EMTEC model based on data analysis and error assessment, as well as the physical principles of the engine flow rate, and compared modelled and test datasets (petrol and diesel tests in the Millbrook facilities) from the on-board diagnostics.
NPL was able to assess the similarity between direct measurements of carbon emissions performed at Millbrook with the EMTEC quantification of emissions derived from the OBD mass flow rate.

NPL have assessed the EMTEC petrol CO2 algorithm and believe it to be a justifiable approach to the calculation of CO2 emissions from vehicle onboard data. The current values of selected parameters and the specific type of engines and fuels give useful information. It was found that the car should be driven for a sufficient amount of time (at least 30 minutes) to produce driving data with an error in estimation of total carbon emissions of below 5%. Specific testing profiles and driving regimes were considered, and the cumulative error of the EMTEC petrol CO2 algorithm was 0.82% after a 2.5-hour test, which is much less than the 5% instrumental uncertainty stated in the specification of the sensors.

 

Impact

The collaboration led to a better understanding of the testing sensors and equipment, and EMTEC received independent assessment of their technology. EMTEC have used the information from NPL to endorse their methods, as shown on their website. EMTEC have increased confidence that their algorithm and associated parameters are suitable for their overall goal. The subsequent comparison between test results and calculated values demonstrated that the differences between the model predictions and reality were acceptably low. This means that they can offer a practical solution to assess real-world fleet vehicle CO2 emissions with real time and cumulative reporting and within acceptable uncertainty limits. This will enable them to support companies with over 500 employees which are mandated to report vehicle emissions.

Working with NPL is a great partnership. Having an independent endorsement of our algorithms and modelling means that we can approach new clients with confidence, and really make an impact on carbon emissions and particulate pollution using connected vehicle technologies.

John White, CCO and Co-Founder - EMTEC

About EMTEC

EMTEC is a UK based start-up founded in July 2017 with a team of 19 people spread across the UK, Europe and Kenya. The goal of the company is to calculate transport-based emissions and pollution through the use of metrics. It has developed a cloud-based platform that receives data from connected vehicles via smart devices, which can then be used to provide real-time analysis of vehicle performance and driver behaviour. EMTEC works with science-based organisations including The Environmental Futures & Big Data Impact Lab in Exeter to enhance its methodologies. EMTEC provides data on vehicle location, trip history, driver behaviour, CO2 emissions as well as acceleration and hard braking metrics. EMTEC technology products and services will be a significant step forward in helping corporations to understand their fleets’ financial and environmental footprints. EMTEC data solutions with automated analysis displayed in EMTEC dashboard, provides a comprehensive overview that puts organisations in control, helps better decision-making, reducing overall financial costs and accelerating a reduction in their carbon footprint by making it easier to understand the electric and hybrid vehicle and financial options available.