Comparison of static and dynamic engine models on the transient performance of a passenger vehicle powertrain

This paper presents experimental and computational results obtained on the Ford Barra 190 4.0 litres I6 gasoline engine and on the Ford Falcon car equipped with this engine. Measurements of steady engine performance, fuel consumption and exhaust emissions were first collected using an automated test facility for a wide range of cam and spark timings vs. throttle position and engine speed. Simulations were performed for a significant number of measured operating points at full and part load by using a coupled Gamma Technologies GT-POWER/GT-COOL engine model for gas exchange, combustion and heat transfer. The fluid model was made up of intake and exhaust systems, oil circuit, coolant circuit and radiator cooling air circuit. The thermal model was made up of finite element components for cylinder head, cylinder, piston, valves and ports and wall thermal masses for pipes. The model was validated versus measured steady state air and fuel flow rates, cylinder pressure parameters, indicated and brake mean effective pressures, and temperature of metal, oil and coolant in selected locations. Computational results agree well with experiments, demonstrating the ability of the approach to produce fairly accurate steady state maps of BMEP and BSFC, as well as to optimize engine operation changing geometry, throttle position, cam and spark timing. Measurements of the transient performance and fuel consumption of the full vehicle were then collected over the NEDC cycle. Simulations were performed by using a coupled Gamma Technologies GT-POWER/GT-COOL/GT-DRIVE model for instantaneous engine gas exchange, combustion and heat transfer and vehicle motion. The full vehicle model is made up of transmission, driveshaft, axles, and car components and the previous engine model. The model was validated with measured fuel flow rates through the engine, engine throttle position, and engine speed and oil and coolant temperatures in selected locations. Instantaneous engine states following a time dependent demand for torque and speed differ from those obtained by interpolating steady state maps of BSFC vs. BMEP and speed. Computational results agree well with experiments, demonstrating the utility of the approach in providing a more accurate prediction of the fuel consumption over test cycles.

The effect of triacetin as a fuel additive to waste cooking biodiesel on engine performance and exhaust emissions

This study investigates the effect of oxygenated fuels on engine performance and exhaust emission under a custom cycle using a fully instrumented 6-cylinder turbocharged diesel engine with a common railinjection system. A range of oxygenated fuels based on waste cooking biodiesel with triacetin as an oxygenated additive were studied. The oxygen ratio was used instead of the equivalence ratio, or air to fuelratio, to better explain the phenomena observed during combustion. It was found that the increased oxygen ratio was associated with an increase in the friction mean effective pressure, brake specific fuel consumption, CO, HC and PN. On the other hand, mechanical efficiency, brake thermal efficiency, CO2, NOx and PM decreased with oxygen ratio. Increasing the oxygen content of the fuel was associated with a decrease in indicated power, brake power, indicated mean effective pressure, brake mean effective pressure, friction power, blow-by, CO2, CO (at higher loads), HC, PM and PN. On the other hand, the brakespecific fuel consumption, brake thermal efficiency and NOx increased by using the oxygenated fuels. Also, by increasing the oxygen content, the accumulation mode count median diameter moved toward the smaller particle sizes. In addition to the oxygen content of fuel, the other physical and chemical properties of the fuels were used to interpret the behavior of the engine.

Modelling greenhouse gas emissions for Australian residential building construction

International pressure to reduce greenhouse gas emissions has forced many countries to look beyond 'demand side' measures. Several industry sectors are examining indirect requirements for energy and other resources that involve significant greenhouse gas emissions. The operation of buildings is responsible for approximately one quarter of greenhouse gas emissions in Australia. Moreover, he construction process consumes vast quantities of raw materials and complex goods and services each year. Each of the processes required for the provision of these products requires energy, and most of this is fossil fuel based. A national model of greenhouse gas emissions is required for residential building construction, to indicate where emissions reduction strategies should focus. A disaggregated input-output model is developed for the Australian residential building construction sector, and recommendations are made about how this model can be used in the development of policies of emissions mitigation for both the sector and individual residential buildings.

Comparative greenhouse emissions anayalsis of domestic solar hot water systems

It is commonly assumed that solar hot water systems save energy and reduce greenhouse emissions relative to conventional fossil fuel-powered systems. Very rarely has the life-cycle greenhouse emissions (including the embodied greenhouse emissions of manufacture) of solar hot water systems been analysed. The extent to which solar hot water systems can reduce emissions compared with conventional systems can be shown through a comparative life-cycle greenhouse emissions analysis. This method determined the time it takes for these net greenhouse emissions savings to occur, or the 'emissions payback period'. This paper presents the results of a life-cycle greenhouse emissions analysis of solar hot water systems in comparison with conventional hot water systems for a southern (Melbourne) and a northern (Brisbane) Australian city.

The characterisation of polycyclic aromatic hydrocarbons emissions from burning of different firewood species in Australia

Four kinds of woods used for residential heating in Australia were selected and burned under two burning conditions in a domestic wood heater installed in a laboratory. The selected wood species included pine (Pinus radiata), red gum (Eucalyptus camaldulensis), sugar gum (Eucalyptus cladocalyx) and yellow box (Eucalyptus melliodora). The two different burning conditions represented fast burning and slow burning, with the air inlet of the combustion chamber respectively ‘full open’ and ‘half open’. By sampling and analysing particulate and gaseous emissions from the burning of each load of wood under defined experimental conditions, PAHs emissions and their profiles in the particulate and gaseous phases were obtained. 16 species out of the 18 selected PAHs were detected. Of these, seven species were detected in the gaseous phase and most were lower molecular weight compounds. Similarly, more than 10 species of PAHs were detected in the particulate phase and these were mostly heavier molecular weight compounds. Under both burning conditions, emission levels for total PAHs and total genotoxic PAHs were the highest for pine and lowest for sugar gum, with red gum being the second highest, followed by yellow box. Using the specific sampling method, gaseous PAHs accounted for above 90% mass fraction of total PAHs in comparison to particulate PAHs (10%). The majority of the genotoxic PAHs were present in the particulate phase. PAHs emission levels in slow burning conditions were generally higher than those in fast burning conditions.

Characterising vehicle emissions from the burning of biodiesel made from vegetable oil

Biodiesel manufactured from canola oil was blended with diesel and used as fuel in two diesel vehicles. This study aimed to test the emissions of diesel engines using blends of 100%, 80%, 60%, 40% , 20% biodiesel and 100% petroleum diesel, and characterise the particulate matter and gaseous emissions, with particular attention to levels of polycyclic aromatic hydrocarbons (PAHs) which are harmful to humans. A real time dust monitor was also used to monitor the continuous dust emissions during the entire testing cycle. The ECE(Euro 2) drive cycle was used for all emission tests. It was found that the particle concentration was up to 33% less when the engine burnt 100% biodiesel, compared to 100% diesel. Particle emission reduced with increased percentages of biodiesel in the fuel blends. Reductions of NOx, HC and CO were limited to about 10% when biodiesel was burned. Levels of CO2 emissions from the use of biodiesel and diesel were similar. Eighteen EPA priority PAHs were targeted, with only 6 species detected in the gaseous phase from the samples . 9 PAHs were detected in particulate phases at much lower levels than gaseous PAHs. Some marked reductions were observed for less toxic gaseous PAHs such as naphthalene when burning 100% biodiesel, but the particulate PAH emissions, which have more implications to adverse health effects, were virtually unchanged and did not show a statistically significant reduction. These findings are useful to gain an understanding of the emissions and environmental impacts of biodiesel.

Study of polycyclic aromatic hydrocarbons emissions from burning of local wood species in Australia

Four kinds of Australian local wood species were burned in a domestic wood heater installed in a laboratory. The selected wood species include pine, red gum, yellow box and sugar gum, that are the most popular domestic fuel wood in Australia. Particulate matter emissions from burning of each load of wood were sampled isokinetically on filter media from the flue by standard stack emission sampling train. The particle laden filters then went for Gas Chromatography/ Mass Spectrometer (GC/MS) analysis to determine polycyclic aromatic hydrocarbons (PAHs) concentrations. The sampling was conducted under two different burning conditions – air inlet of the combustion chamber fully open and half open. Approximately 15 types of PAHs were detected. Emission factors were derived as microgram of PAHs /kg of wood burned. Total particulate emission factors were also obtained from gravimetric measurement before and after the sampling. PAH emission profiles for four species were generated from the results. Comparisons of emission factors have been conducted among different species of wood, as well as under different burning conditions, ie. fast burning and slowing burning. According to the derived emission factors, pine displayed the highest level of PAHs among the four species, followed by red gum and yellow box, whereas sugar gum showed the lowest level of PAHs. Emission factors were compared between each type of wood under two different burning conditions, the slow burning condition, which was air inlet half open, clearly showed higher PAH levels compared to the fast burning condition. Total PAH fractions on particulate matter were calculated and compared among wood types under two burning conditions. During the fast burning condition, red gum and pine have the higher percentage of PAH to total particulate matter emission than sugar gum and yellow box. When changed to slow burning, the PAH fraction on particulate matter are all increased with sugar gum having the largest increase.