A Methodology for Minimising Emissions Constrained Cold Start Fuel Consumption

Abstract

The cold start emissions from gasoline fuelled vehicles are a major challenge when meeting vehicle emissions regulation. Vehicle manufacturers therefore undertake extensive design and testing of the entire exhaust and engine control systems, which is both time consuming and costly. This is particularly an issue with the growing number of control parameters in modern powertrains. This paper presents a methodology that integrates appropriate physics-based models of the engine and aftertreatment into a numerical optimisation scheme, and is proposed as a possible means of reducing this calibration effort. The methodology is demonstrated over a prescribed drive cycle by identifying the optimal spark timing trajectory that maximises fuel economy while meeting emissions constraints. The trends in the resulting control policy are explained and the results are validated where possible.

Development of automotive emissions testing equipment and test methods in response to legislative, technical and commercial requirements

“…In addition to these legal testing requirements for SI vehicles, performing tests at a various ambient temperatures is of interest in multiple areas, such as: fuel research, catalyst research, powertrain development and research into regulated and unregulated emissions and 'real-world' emissions behaviours. Cold start testing has been identified as an activity of prime importance for manufacturers of vehicles with SI engines [10]. While the introduction of progressively stricter emissions standards and a cold start test at -7 °C have themselves had a great impact on the testing requirements of manufacturers of engine, vehicle and aftertreatment systems, measures to control emissions and fuel consumption during cold start have increased the number of system parameters, thereby causing a further increase in testing requirements [10].…”

“…Cold start testing has been identified as an activity of prime importance for manufacturers of vehicles with SI engines [10]. While the introduction of progressively stricter emissions standards and a cold start test at -7 °C have themselves had a great impact on the testing requirements of manufacturers of engine, vehicle and aftertreatment systems, measures to control emissions and fuel consumption during cold start have increased the number of system parameters, thereby causing a further increase in testing requirements [10]. Given the complexity of these systems, and the low emissions limits, the ability to collect data on engine out emissions, catalyst efficiency, catalyst temperature, etc, in addition to 'traditional' bag-sampled tailpipe emissions is a distinct advantage.…”

“…During operation of the chamber, (including during the execution of emission and vehicle performance tests), the chamber permits: normowanych oraz rzeczywistych emisji samochodowych. Rozruch zimnego silnika został zidentyfikowany jako zdarzenie wysokiej wagi dla producentów silników o zapłonie iskrowym [10]. Przy okazji wdrażania coraz surowszych standardów emisji spalin, które miały ogromny wpływ na producentów silników spalinowych, konstrukcję systemów recyrkulacji i katalitycznego oczyszczania spalin, okazało się, że podczas zimnych rozruchów należy kontrolować o wiele więcej parametrów jednocześnie niż podczas innych stanów pracy silnika, co wzmaga konieczność zwiększenia wymagań badawczych.…”