The aim of this study was to compare and evaluate the production of exhaust emissions from a vehicle with a petrol engine with the Euro 4 emission standard and powered by petrol and LPG (liquefied petroleum gas). The paper presents new possibilities for monitoring exhaust emissions using an exhaust gas analyzer. At the same time, it points out the topicality and significance of the issue in the monitored area. It examines the impact of a change in fuel on emissions. This change is monitored in various areas of vehicle operation. Measurements were performed during real operation, which means that the results are fully usable and applicable in practice. The driving simulation as well as the test conditions correspond to the RDE (Real Driving Emissions) test standard. A commercially available car was first selected to perform the tests, which was first measured in the original configuration (petrol drive). Based on real-time RDE driving tests, it is possible to determine the number of exhaust emissions. Subsequently, the same measurements were performed with the same vehicle, but the vehicle’s propulsion was changed to LPG. The vehicle was equipped with an additional system that allowed the vehicle to be powered by LPG. The results from the individual driving tests allowed the determination of the exhaust emissions. Emissions of CO (carbon monoxide), CO₂ (carbon dioxide), HC (hydrocarbons), and NO_x (nitrogen oxides) were monitored as a matter of priority. Through the driving tests, it was found that the gasoline combustion produced higher CO (1.926 g/km) and CO₂ (217.693 g/km) emissions compared to the combustion of liquefied gas, where the concentration of the CO emissions was 1.892 g/km and that of the CO₂ emissions was 213.966 g/km. In contrast, the HC (0.00397 g/km) and NO_x (0.03107 g/km) emissions were lower when petrol was burned. During LPG combustion, the HC emissions reached 0.00430 g/km, and the NO_x emissions reached 0.05134 g/km. At the end of the research, the authors compared the emissions determined by real driving (in g/km) with the emission values produced by the emission standard EURO 4 and the certificate of conformity (COC). Practical measurements showed that the vehicle produced excessive amounts of CO when burning gasoline. This production is 0.926 g/km higher and 0.892 g/km higher when burning LPG compared to the limit set by the Euro 4 Emission Standard. The difference is even greater than the limit value stated in the COC document. For other substances, the monitored values are in the norm and are even far below the permitted value

The amount of hybrid vehicles and their contribution have increased in the global market. They are a promising aspect for a decrease in emissions. Different tests are used to determine the factors of such emissions. The goal of the present study was to compare the emissions of two hybrid vehicles of the same manufacturer: the plug-in version and the HEV version (gasoline + electric engine). These vehicles were chosen because they comprise the largest market share of hybrid cars in Poland. The exhaust emission tests were conducted in the WLTC tests on a chassis dynamometer and under real traffic conditions. Simultaneous testing on a dyno and under real driving is the most adequate test to assess the environmental aspects of vehicles—especially hybrids. The combustion engines of the tested vehicles were supplied with gasoline containing 5% biocomponents. The emissions, including CO₂, CO, NO_x, THC and PNs, were measured in accordance with the European Union procedure. According to the latter, the resistance to motion of the chassis dyno was adjusted to the road load, allowing the hybrid vehicles to move in electric mode and allowing the dynamometer to operate in energy recovery mode. The obtained emissions of CO₂, CO, NO_x and THC in the case of the plug-in hybrid vehicle were lower by 3%, 2%, 25%, and 13%, respectively, compared to the case of HEV. Fuel consumption in the case of the plug-in hybrid vehicle was lower by 3%, and PN was lower by 10% compared to the case of HEV (WLTC). In real driving conditions, the differences were more pronounced in favour of the plug-in vehicle: CO₂ emissions in the RDE test were 30% lower, NO_x emissions were 50% lower, and PN was 10% lower. An increase in emissions was only observed for CO₂ emissions—the plug-in vehicle’s on-road emissions were 6% higher compared to the HEV. The obtained emissions for FC and PN varied with actual velocity values due to competitive driving between a combustion engine and an electric motor, as well as existing acceleration and deceleration events during the test and other factors.

Existing methods of determining vehicle velocity based on measurements of body deformation have been based on linear models. This means that the linear relationship between the equivalent energy speed (EES), which is a measure of the kinetic energy lost during the collision of cars, and the value of the ratio C_s, representing the average value of the body deformation, has been sought. The aim of this publication is to present a nonlinear and innovative quick method, or its simpler form, using linearisation in the seven consecutive ranges, for determining EES on the basis of the averaged deformation ratio C_s. The most critical factor for this analysis has been the coefficient b_k, representing the slope of the linear relationship. Its fixed value is appropriate only for the rare case of a linear response of a system of cars interacting during a collision with the internal forces generated in the collision, and carrying out the work of deformation. In a more general case, the assumption of a fixed value of the coefficient b_k, based on the tables for each class of vehicles, can lead to an EES estimation error greater than 30%. This results in a significant difference between the calculated speed and actual speed. The use of a nonlinear model can be a better solution but, on the other hand, it can result in an increase in computation time due to a very small iteration time step and problems of solution convergence due to computation instability. The innovative compromise for such a situation has been the use of linear estimation with different slopes for each of the consecutive seven ranges, which together contain values of the deformation ratio C_s from 0.24 to 0.7. With such an assumption, and using the polynomial regression equations to calculate the b_k coefficient, the authors have obtained an improvement in the accuracy of EES estimation with an error of 2%. Additionally, this enables the use of a quicker computation algorithm.

The publication proposes a non-linear method for determining the pre-crash velocity of the ‘Luxury’ vehicle class as defined by the National Highway Traffic Safety Administration database. Existing methods of vehicle velocity evaluation are based on the linear relationship between the energy equivalent speed and the value of the car body deformation coefficient C_s, which lead to a significant estimation error, rendering them insufficient for car crash experts. The non-linear model includes linearisation in particular ranges, which may decrease the error value. The most important element in the non-linear method is the b_k coefficient, which is calculated based on polynomial regression equations. The article presents an optimisation iteration, which procures accurate results with a reduced computation time for the ‘Luxury’ vehicle class.