The sight of declaration of public health emergency in New Delhi due to poor air quality is still fresh in our minds. We can vividly recall the third edition of the odd-even rotation scheme that was put in place in a bid to limit the number of on-road cars as well as curb pollution.

The automotive sector accounts for around 23 % of greenhouse gas emissions [1] and 20 % of total CO2 emissions [2] globally, leading to creation of stringent emission standards for compliance by vehicle manufacturers worldwide. Emission standards, such as Tier 2 bin 5 (2007), LEV II ULEV (2008) and LEV III (2025) in the USA, Euro 2 (1996) to Euro 6 (2014) in Europe, Bharat Stage III, Bharat Stage IV and Bharat Stage VI have set quantitative limits on the permissible amount on air pollutants that may be released by automobiles while in use. We have seen how these emission standards worldwide have evolved and become stringent over a period as shown in Figure 1.

[1] Reference Global EV Outlook, IEA
[2] World Bank data

Figure 1: Historical evolution of European and US emission limits for diesel and gasoline (petrol) engines

The complexities in automobiles are also growing by the minute, not only in engine design but also in the millions of lines of software code in vehicles. Thus, the role of software has become increasingly important for preventing pollution and getting the vehicle to comply with emission norms.

Reducing Nox Pollutants To 95 %

Over the years, various vehicle emission control compliance programmes have evolved from merely verifying prototype and new production vehicles towards in-use testing and durability requirements so that emission standards are met throughout the useful life of a vehicle.

In recent years, diesel engines have been modified for low NOx formation by optimisation of the fuel injection timing, rate and spray configuration, injector valve timing, supercharging, compression ratio and mixing in the combustion space. All these methods are targeted towards lowering the peak combustion temperature, and therefore, the amount of NOx formed. Unfortunately, the amount of particulate matter (PM) and unburnt hydrocarbons (HC) increases, and there is a fall in fuel efficiency due to poor combustion. Exhaust gas aftertreatment with Selective Catalytic Reduction (SCR) results in 90-95 % reduction in NOx levels.

Developments over the years have led to the reduction of NOx levels from 70 % to 95% and this was achieved through a combination of engine controls as well as aftertreatment methods.

Engine controls (primary methods) help in reducing NOx levels to some extent, which in turn, help the aftertreatment controls (secondary method) to achieve 95 % NOx reduction.

Enabling Further Nox Reduction Up To 99 %

Software improvements with the introduction and deployment of various research algorithms in the engine and aftertreatment control have enabled further NOx reductions. Controller algorithms were improved by varying the urea dosing rate in the exhaust based on the outlet NOx emitted and taking into account the NOx slip at the catalyst. With this improvement, 99 % of the conversion efficiency was achieved. This is an example of growth in the software along with the minor changes to hardware that helps reduce NOx to a great extent.

Determining Vehicle Performance

Vehicle diagnostics have been designed for every functionality of the system to determine vehicle performance. These diagnostics comprise rationality diagnostics such as sensor-related diagnostics (sensors tampering, out-of-range/ in-range reading of sensors, stuck-in-range reading of the sensor) determining the health of the hardware. They also comprise system performance diagnostics such as conversion efficiency diagnostics, catalyst/filter missing diagnostics, offset determination in the sensor as well as detecting adulteration in urea or fuel diagnostics. These diagnostics have enabled the system to become more robust and efficient. The further development of virtual sensors based on thermodynamics also helps improve system dynamics and reduces costs.

Using Software For Vehicle Emission Testing Programmes

Regulators measure the emission levels of test vehicles in controlled settings. However, the black-box nature of this testing and the standardisation of its forms, bring in the additional need and support of reliable software for intensive vehicle testing.

From laboratory testing, enhanced laboratory testing, on-road testing to on-road data-recording, advanced vehicle emission testing technologies provide tools to test vehicles in different scenarios and provide required accuracy, repeatability and automation. These software-based tools are compliant with legislation. Most of the test scenarios in contemporary times are created on a robust software platform and compared with real-time values to check the emission levels for certification.

As strategic software partners to global auto OEMs and Tier I suppliers in the development of embedded software for next-gen conventional and alternative powertrains, we assess the initial requirement, evaluate the feasibility of the requirement, and thereafter propose various software solutions. We continue to help our partners in reimaging mobility through our cutting-edge software and technologies within the automobile industry for a greener, safer, pollution-free, better world.

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