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Technical Paper

Experimental Investigation of Fuel Consumption and Exhaust Emissions of a 16V Pent-Roof Engine Fueled by Gasoline and CNG

2001-03-05
2001-01-1191
A systematic experimental investigation was undertaken to compare the fuel consumption and exhaust emissions of a production SI engine fueled by either gasoline or compressed natural gas (CNG). The investigation was carried out on a two-liter four-cylinder engine featuring a fast-burn pent-roof chamber, one centrally located spark plug, four valves per cylinder and variable intake-system geometry. The engine was originally designed at Fiat to operate with unleaded gasoline and was then converted at Politecnico di Torino to run on CNG. A Magneti Marelli IAW electronic module for injection-duration and spark-advance setting was used to obtain a carefully controlled multipoint sequential injection for both fuels.
Technical Paper

Influences of Gas Quality on a Natural Gas Engine

2001-03-05
2001-01-1194
1 The topic of investigation of this work was the influence of different gas qualities on the engine parameters and particularly on the air excess factor λ. For this research the normalized gases with extreme compositions were used. At stationary operation there are no differences of the leaning capability of the different gases. The gas with the highest content of inert components causes the lowest full load power, the highest fuel consumption and the highest cyclic irregularity. With the same air flow and the same injection duration for different gases result different air excess factors λ according to the density and to the necessary stoichiometric air quantity of each gas. This fact influences the λ at transient operation conditions as: cold starting, gas quality jump, or load increase, if there is no λ-control. With an active λ-control, which is today fast enough, especially with an adaptive system there are no problems with λ- differences.
Technical Paper

Sounddesign - the BMW Inline Six-Cylinder Engine in Different Vehicle Applications

2001-04-30
2001-01-1428
The new inline six-cylinder engine from BMW notoriously sets new standards on objective performance in power and torque and fuel consumption as well as on “Laufkultur” (engine refinement). It has been a general movement in recent years to design engines that not only perform, but also improve driver's feedback for performance on an emotional level. New is the degree of differentiation of this new engine through distinctive sound design for the whole bandwidth of vehicle categories ranging from a 5-Series luxury sedan to a Z3 roadster, or an X5 sports utility vehicle to a 3-Series compact car. For each BMW class, the intake and exhaust systems of the inline 6-cylinder engines have been tuned to highlight the subjective impression of performance according to the appropriate vehicle type.
Technical Paper

Optimization Elements for Externally Controlled Air Conditioning Systems

2001-05-14
2001-01-1733
In order to reduce the fuel overconsumption, new air conditioning systems fitted with externally controlled compressors have been implemented. Their operating principle consists in driving electrically (external control) the compressor displacement in order to adjust the cooling capacity delivered by the A/C system to the cooling capacity required by the passenger compartment. Therefore, it is possible to reduce the mechanical power absorbed by the compressor and by this means, the fuel overconsumption. However, this potential of fuel consumption reduction can be only achieved under the condition that the other components of the A/C system, such as the thermostatic expansion valve (TxV), are well adapted all together in order to fully take advantage of the implementation of such new type of compressors. The paper describes the different possibilities of optimization of the TxV in regard to hunting phenomena.
Technical Paper

Economical Engine Cooling System

2001-05-14
2001-01-1708
The previous study presented during the last VTMS 4 showed the following results, for all engine cooling system and depending on the vehicles: Cost reduction by - 10 to -15%, Weight reduction by -15 to - 21%, Coolant volume reduction by -25% Fuel consumption by -3%, Thermal comfort improvement. Despite of these good results, most of car manufacturers hesitated to use this new concept due to this technological breakthrough of engine cooling system because of expensive durability studies. In this paper the electric fan has been simply suppressed and replaced by the heating blower allowing to cool the engine at idle and at low vehicle speed. By suppressing the electric cooling fan, the advantages of this new economical engine cooling system become: cost reduction up to - 30%, weight reduction up to - 30%.
Technical Paper

A Compact Cooling System (CCS™): The Key to Meet Future Demands in Heavy Truck Cooling

2001-05-14
2001-01-1709
To meet future needs for heavy truck cooling, a novel high performance radial compact cooling system (CCS) was developed. Measurements with a prototype system were conducted in a component wind tunnel and with truck-installed systems in a climatic vehicular wind tunnel. The CSS is compared to conventional axial and side-by-side systems. In comparison with a conventional axial system, the performance per unit volume of the CCS is 42% higher, the noise level is about 6 dB lower and the power consumption of the radial fan is 70% of the axial fan leading to significant savings in fuel consumption.
Technical Paper

Instabilities Occurring in an Automotive A/C Loop Equipped with an Externally Controlled Compressor and a Thermal Expansion Valve

2001-05-14
2001-01-1717
The new compressor generation, called externally controlled compressors, is able to be electronically driven from zero to its maximum displacement. The cooling power can be adjusted to the exact need and this way the fuel consumption of the automotive A/C loop can be reduced. Unfortunately, for the mean and low thermal loads on the evaporator, this new opportunity is limited by A/C loop operation instabilities. Thanks to an automatic approach of the coupling TxV - Evaporator, we can explain the origin of these instabilities and we can show the involvement of this new compressor generation. Then we propose different improvements such as: a better account of the automatic parameters of the TxV and the evaporator (gains, time constants). a TxV setting modification. a new generation of TxV with a leakage. These solutions are discussed according to their interest.
Technical Paper

Parking Cooling Systems for Truck Cabins

2001-05-14
2001-01-1728
Engine independent AC-systems, or parking cooling systems for non-idling air conditioning are getting more and more important, because extremely uncomfortable conditions during breaks or a disproportionate amount of fuel consumption for engine idling during breaks are not longer accepted. For cost, weight and package reasons today only thermal storage systems are ready for series production of in series production. The benefits (comfort and fuel savings) and test results of such a system are shown. Future developments of fuel cells or new alternator/battery-systems will probably change this evaluation.
Technical Paper

Modeling of Engine Warm-Up with Integration of Vehicle and Engine Cycle Simulation

2001-05-14
2001-01-1697
The incorporation of a detailed engine process calculation that takes into account thermal behavior of the engine and exhaust system is essential for a realistic simulation of transient vehicle operation. This is the only possible way to have a precise preliminary calculation of fuel consumption and emissions. Therefore, a comprehensive thermal network of the engine based on the lumped capacity method has been developed. The model allows the computation of component temperatures in steady state operation as well as in transient engine studies, e.g. investigations of engine warm-up. The model is integrated in a co-simulation environment consisting of a detailed vehicle and engine cycle simulation code. The paper describes the procedure of the co-simulation and presents several examples of warm-up simulations.
Technical Paper

Comprehensive Combustion Noise Optimization

2001-04-30
2001-01-1510
Combustion noise plays a considerable role in the acoustic tuning of gasoline and diesel engines. Even though noise levels of modern diesel engines reach extremely low values, they are still higher than those of conventional gasoline engines. On the other hand, new combustion procedures designed to improve fuel consumption lead to elevated combustion noise excitations as in case of today's direct injecting gasoline engines whose vibration excitation and airborne noise emissions are slightly increased during stratified operation. The partly conflicting development goals resulting from this can only be realized by integrating the NVH specialists' expertise into every development step from concept to SOP.
Technical Paper

Advanced Engine Cooling Thermal Management System on a Dual Voltage 42V-14V Minivan

2001-05-14
2001-01-1742
Today the worldwide convergence towards stricter fuel consumption and emission regulations is pushing carmakers and suppliers into new fields of innovation. Valeo Engine Cooling, VEC, is contributing towards these goals by applying its thermal management system expertise in order to reduce fuel consumption and emissions by using an advanced engine cooling system that incorporated variable speed PWM fans, an electric water pump and an electric water control valve. The paper discusses the benefits in terms of engine cooling, fuel economy and emissions over the FTP drive cycle. The paper gives some examples of advanced engine cooling strategies based on a virtual, predictive metal temperature sensor that is used to actuate the electrical water pump at the desired flow rate. The electrical balance between the 42V pump and fans has also been optimized to reduce the vehicle electrical power consumption and to keep the coolant temperature close to 110°C.
Technical Paper

Development of EGR Coolers for Truck and Passenger Car Application

2001-05-14
2001-01-1748
The new European legislation (EURO III) for emission reduction was mainly reached by combustion optimization. This lead to a higher fuel consumption, which can be compensated by cooled EGR. One of the described coolers is the first known EGR cooler for series truck application in Europe and is in production since mid of year 2000. Also for the next legislation step (EURO IV) cooled EGR is one of the most promising solutions. The design criteria and production issues of a tube and shell type EGR cooler for truck application and a tube plate design for a high volume production cooler for passenger car will be described.
Technical Paper

Laser Welding of EGR Coolers - A New Process Technology for Heat Exchanger Manufacturing

2001-05-14
2001-01-1753
Laser welding is a joining process, which is comparatively new to industrial production and especially to heat exchanger manufacturing. Due to the high energy density of the laser beam, the process is characterized by faster welding speeds with deep penetration as compared to the conventional welding processes. Therefore laser welding technology is widely used in the automotive industry on a variety of different applications. This paper describes the application of laser welding as possible joining technology for exhaust gas heat exchangers made of stainless steel. The cooled exhaust gas recirculation (EGR) technology shows good potential for meeting the actual and future emission targets of diesel engines combined with acceptable fuel consumption. It will be shown that the selection of the base metal and the joining technology are extremely important for the durability of the product because of the severe operating environment the EGR cooler must endure.
Technical Paper

Fuel Economy Improvements through Improved Automatic Transmission Warmup - Stand Alone Oil to Air (OTA) Transmission Cooling Strategy with Thermostatic Cold Flow Bypass Valve

2001-05-14
2001-01-1760
The stand alone oil to air (OTA) transmission cooling strategy with thermostatic cold flow bypass valve has been shown to be an effective means of improving the warmup of an automatic transmission. Improving the system warmup rate of an automatic transmission significantly improves its efficiency by reducing losses resulting from extremely viscous transmission fluid and can allow for calibration changes that improve overall transmission performance. Improved transmission efficiency in turn allows for improved engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency result in an overall increase in vehicle fuel economy. Fuel economy and consumption are important parameters considered by the vehicle manufacturer and the customer. Fuel economy can be considered as important as reliability and durability.
Technical Paper

The Influence of an On Line Oil Recycler on Oil Quality from a Bus in Service Using Synthetic Oil

2001-05-07
2001-01-1969
A method of cleaning lubricating oil on line was investigated using a one micron bypass particulate filter followed by an infra-red heater, to remove water, dissolved gases and light diesel fractions in the oil. The impact of this oil recycler on oil quality was studied using synthetic oil in an on-road bus test. The bus was of Euro-1 emissions standard and equipped with a Cummins 6 cylinder 8.3 litre turbo-charged inter-cooled DI engine. Comparisons tests were undertaken with and without the oil recycler for about 28,000 miles. Oil samples were analysed about every 2000 miles. The results showed that the on line oil recycler achieved significant improvements in the oil quality. With the recycler, the TBN depletion rate was reduced by 52%, the TAN increase rate was reduced by 27% and the carbon accumulation rate in the oil was reduced by 42%. The fuel dilution was reduced by the recycler.
Technical Paper

New Data on Flame Behaviour in Lean Burn S.I. Engine

2001-05-07
2001-01-1956
The concept of lean-burn combustion in spark ignition engines had been developed for reducing both exhaust emissions and fuel consumption. However the operation of engines in this mode is limited due to the misfire phenomenon. Several studies have been conducted to improve the understanding of the interaction between flow-field, mixture preparation and the progress of combustion. Multidimensional optical diagnostics are an important tool and in the other hand, the work done on combustion modelling in engine becomes more and more relevant but mainly in the case of stoichiometric mixture. The objective of the present work is to provide new information on the flame structure in lean mixtures under different flow field configurations, particularly when the flame is in the laminar-turbulent transition. Classical Mie scattering tomography of flames was performed in a transparent 4-valve Spark Ignition engine.
Technical Paper

Lubricants That Optimize Diesel Engine Fuel Economy and Allow Extended Oil Drains

2001-05-07
2001-01-1968
Fleet customers demand reduced operating costs. This necessitates the development of engine oils which can provide maximum fuel economy and extended oil drains, while still maintaining engine durability. This is particularly important in diesel engines produced since October 1998. These engines use retarded timing to meet EPA's emission requirements and, as a consequence in some cases, generate high soot levels in the engine oil. Extended oil drains in 1995 Caterpillar 3406E and 1996 Detroit Diesel Series 60 engines found no statistical difference in fuel economy or wear between a synthetic SAE 5W-40 and an SAE 15W-40 using API Group II base stocks. Both oils had the same API CG-4/SJ quality level. Soot levels at oil drains of 40,000-50,000 miles (64,372 - 80,465 km) ranged from 0.5-1.2%.
Technical Paper

The Use of Emulsion, Water Induction and EGR for Controlling Diesel Engine Emissions

2001-05-07
2001-01-1941
A comparative experimental investigation into the use of water-in-diesel fuel emulsion, inlet manifold water induction and Exhaust Gas Recirculation (EGR) as means of controlling diesel engine emissions has been carried out. The tests were performed on a 2.5 l, four-cylinder, direct injection Ford diesel engine. The engine was modified to incorporate a water injection system into the air intake and an EGR system. Water-in-fuel emulsion was prepared by mixing and circulating the mixture for an appropriate length of time prior to injection into the engine. A computerised data acquisition system capable of logging the engine performance parameters (cylinder pressure, engine speed, engine load … etc) was also developed and used to obtain the required data. The amount of water in the emulsion was varied, as was the amount of water introduced into the intake manifold and the amount of EGR. The exhaust emissions from the engine were analysed for smoke, NOX, uHC, CO, CO2 and oxygen.
Technical Paper

Strategies for Meeting Future Harmonised Emissions Standards if Sport Utility Vehicles with Direct Injection Diesel Engines

2001-05-07
2001-01-1932
Future emissions standards (TIER II, LEV2) require that diesel fuelled vehicles meet the same emissions levels as their gasoline counterparts. In addition, Sport Utility Vehicles (SUVs) must comply to the same norms as passenger cars. However the diesel engine has many desirable attributes for SUV applications and an important role to play in addressing fuel consumption and CO2 emissions issues. In-cylinder reduction of pollutants can no longer be relied upon as the major means to meet future standards. Solutions based solely on emissions control technology are also unlikely to yield positive results. The only viable solution is the combined use of in-cylinder emissions control with advanced catalyst technologies. However, a highly integrated approach is required to gain maximum benefit from the technologies used and enable very low targets to be achieved.
Technical Paper

Oil Quality with Oil Age in an IDI Diesel Passenger Car Using an On Line Lubricating Oil Recycler Under Real World Driving

2001-05-07
2001-01-1898
A method of cleaning lubricating oil on line was investigated using a fine 1 micron bypass particulate filter, followed by an infra-red heater to remove water and light diesel fractions in the oil. A Ford 1.8 litre IDI diesel passenger car was investigated under real world driving conditions. Comparison was made with the oil quality without the recycler. All the tests were carried out on the same vehicle over 7000 miles with and without the recycler. The results showed that the on line oil recycler cleaning system reduced the rate of reduction of TBN and the rate of increase of TAN by 54% and 50% respectively. The reduction in the rate of carbon accumulation in the oil was 42%. There was also a reduction in fuel dilution. All the wear metals in the oil were greatly reduced by the recycler, the iron was reduced by 76%, the lead was reduced by 85% and the aluminum was totally removed.
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