A New Method to Calculate Instantaneous Vehicle Emissions using OBD Data

Abstract

The actual type approval procedure of vehicles, based on a fixed driving cycle for all the vehicles (NEDC), is not representative of their real on-road usage: the driving style and its influence on consumption and emissions cannot be neglected. The on road impact of vehicles on their real use is not known and it is difficult to measure (the PEMS are expensive, have big volume and mass and need continuous maintenance); the objective of this work is to develop a methodology to calculate in real time the energy and environmental impact of spark ignition vehicles, using the onboard sensors of the vehicle and emissions models to calculate them.An onboard instrumentation able to communicate with the electronic system of the vehicle (OBD/CAN) was developed to collect all the sensor data installed on a vehicle: those values are used as input values to the emissions models of CO 2 , CO, HC and NO x developed in the present work. The CO 2 and CO have been calculated using a chemical equilibrium combustion model with 6 combustion products, with the equilibrium temperature used as a calibration constant. HC and NOx, produced during transients, are assumed to be dependent from the accelerator pedal gradient, but during engine cold start also from the catalyst temperature.To validate the models, a spark ignition hybrid vehicle, the Honda Civic Hybrid has been tested on a chassis dynamometer running the three Artemis driving cycles. The emissions have been measured with the CVS (taken as reference) and with a portable emission analyzer, (Horiba OBS 1300), used for comparison with the models. The results shows that the values calculated by the models are comparable with those measured by OBS, but for HC and NO x are better because the OBS gave inaccuracies due to its high minimum resolution.

Comparison of exhaust emission on the basis of Real Driving Emissions measurements and simulations

“…4). This instrument has been designed to measure exhaust emissions in real traffic conditions and meets the requirements of the relevant standards [12][13][14][15]. For the concentration of harmful compounds in the exhaust can be refer to the driving characteristics and conditions of the drive system, the Semtech DS device enables communication with the vehicle diagnostic system.…”

The Parameters of Passenger Cars Engine in Terms of Real Drive Emission Test

“…from the data from internal computer network of the vehicles. The difficulty here is to develop the indicator of engine load, as in passenger vehicles the on-board diagnostic system provides only a supportive parameter, which is the engine load at a given engine speed expressed as a percentage [13,14]. As a result we should obtain a defined engine operation area, which should be subject to the test, i.e.…”

A New Ecological Research – Real Driving Emissions

“…The lack of legal provisions regarding the testing of emissions in real traffic conditions resulted in the need to determine common areas of operating of the engines in order to enable the comparison between the engines [1]. The concept of exhaust gas toxicity tests performed in real traffic conditions for passenger vehicles should be based on the following premises: determination of a consistent area of operation of the engine for all passenger vehicles in a way to the greatest extent corresponding with the most common traffic conditions, determination of the parameters measured during the road tests and the obtained emission indicators [2,3]. The article presents the results of the measurements concerning determination of working conditions for the engines used to drive the cars.…”

“…The regulations permitting the vehicle to drive on roads (homologations and production conformity), periodical inspections of the vehicle technical condition and other legal acts directly or indirectly related to the production, use and disposal of used up civilization products treat the environmental issues in a complex way. In the previous years in individual countries, there were different inspection and testing systems related to the exhaust emissions yet for some time now, there has been a far-reaching unification going on [1][2][3].…”