Search Results

This work presents a physical model that calculates the efficiency maps of the inverter-fed Permanent Magnet Synchronous Machine (PMSM) drive. The corresponding electrical machine and its controller are implemented based on the two-phase (d-q) equivalent circuits that take into account the copper loss as well as the iron loss of the PMSM. A control strategy that optimizes the machine efficiency is applied in the controller to maximize the possible output torque. In addition, the model applies an analytical method to predict the losses of the voltage source inverter. Consequently, the efficiency maps within the entire operating region of the PMSM drive can be derived from the simulation results, and they are used to represent electric drives in the system simulation model of electric vehicles (EVs).

This paper presents an overview of the results on light duty vehicles collected in the “PARTICULATES” project which aimed at the characterization of exhaust particle emissions from road vehicles. A novel measurement protocol, developed to promote the production of nucleation mode particles over transient cycles, has been successfully employed in several labs to evaluate a wide range of particulate properties with a range of light duty vehicles and fuels. The measured properties included particle number, with focus separately on nucleation mode and solid particles, particle active surface and total mass. The vehicle sample consisted of 22 cars, including conventional diesels, particle filter equipped diesels, port fuel injected and direct injection spark ignition cars. Four diesel and three gasoline fuels were used, mainly differentiated with respect to their sulfur content which was ranging from 300 to below 10 mg/kg.

This paper presents a novel partial flow sampling system for the characterization of airborne exhaust particle emissions. The sampled aerosol is first conditioned in a porous dilutor and then subsequent ejector dilutors are used to decrease its concentration to the range of the instrumentation used. First we examine the sensitivity of aerosol properties to boundary sampling conditions. This information is then used to select suitable sampling parameters to distinguish both the nucleation and the accumulation mode. Selecting appropriate sampling parameters, it is demonstrated that a distinct nucleation mode can be formed and measured with different instruments. Using these parameters we examine the performance of the system over transient vehicle operation. Additionally, we performed calculations of particle losses in the various components of the system which are then used to correct signals from the instruments.

The results of an investigation of the influence of the sulphur fuel content and different dilution techniques on fine particulate emissions are reported in this paper. Fuels with two different sulphur contents (<10 ppm and approx. 200 ppm) were used for a Diesel and a gasoline vehicle in order to compare four different dilution procedures. These comprised the standard CVS tunnel and two pre-heated and one non-heated direct dilution systems. Various particulate measurement instruments were employed simultaneously, including SMPS, CPC, and ELPI for number and size, the standard gravimetric filter method for mass. In addition, Soxhlet extraction for chemical composition was carried out. A higher fuel sulphur content was found to clearly increase particulate emissions from the Diesel and the gasoline vehicle for higher load. The increase in emissions was due to the contribution of condensed material and most of it could be clearly brought into relation with to sulphur compounds.

The results of an investigation on PM emissions over an extended range of engine technologies are reported in this paper. These included modern Diesel vehicles, a particle trap equipped Diesel vehicle, a port-injected gasoline vehicle and direct injection gasoline vehicles. Various particulate measurement instruments were employed simultaneously, including SMPS, CPC, ELPI, for number and size and the standard gravimetric filter method for mass. Soxhlet extraction was applied to determine the chemical composition. The particle emissions showed a wide range in concentration for the different vehicles. The particle concentration of the port-injected gasoline vehicle and the trap-equipped Diesel vehicle were observed at background level.

The findings presented in this paper result from a collaboration between two Federal Laboratories in Switzerland. In this research project the characteristics of the particulates from internal combustion engines were investigated in detail. Measurements were carried out on a single-cylinder research engine focusing on exhaust particulate matter emissions. The single-cylinder diesel engine is supercharged and features a common-rail direct injection system. This work analyzes the influence of fuel properties and injection parameters on the particulate number size distribution. For the fuel composition, five different fuels including low sulfur diesel, zero-sulfur and zero-aromatics diesel, two blending portions of oxygenated diesel additive and rapeseedmethylester were used. For the injection parameters the injection pressure, the start of injection and the fuel amount in the pilot- and in the post-injection phases were varied.

In this paper, we present the results of an experimental study on particulate emissions of gasoline vehicles. The objective of the project was to investigate the particulate emissions on the basis of number and total mass and to gain experience in the influence of the sampling method on the results. The measurements were carried out with three passenger cars at a chassis dynamometer. Two vehicles with premixed combustion and one direct injection engine were tested at constant loads and driving cycles. For the aerosol sampling we used a standard CVS system, an ejector and a rotating disk unit. The samples were analyzed by SMPS and ELPI. Samples for gravimetric analysis were taken downstream of the CVS tunnel and from a mini tunnel. The results show that all three vehicles produce significantly less particulate in number and mass than a common diesel vehicle.

The relative amounts of heat released by premixed and by diffusion controlled combustion is varied in a compression-ignition engine run on the test bench through variation of four operating parameters. Exhaust gas is led to a differential mobility particle sizer and to filters that are loaded for gravimetric analysis. Particle size distributions are acquired in the 16÷630 nm range of electrical mobility diameters. Opacity readings of the exhaust gas are taken, cylinder pressure is indicated, a value for the combustion noise is computed; gaseous emissions are recorded and heat release rates based on cylinder pressure analysis are evaluated. Two full factorial experiments at 2 bar bmep 2000 rpm are run as 24 combinations of four factors: Injection pressure 400 and 1200 bar, with and without pilot injection, 1/3 and 1/4 mass-fraction exhaust gas recirculation, late, middle and early start of injection.