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Technical Paper

The Application of Solid Selective Catalytic Reduction on Heavy-Duty Diesel Engine

2017-10-08
2017-01-2364
Abstract Urea SCR technology is the most promising technique to reduce NOx emissions from heavy duty diesel engines. 32.5wt% aqueous urea solution is widely used as ammonia storage species for the urea SCR process. The thermolysis and hydrolysis of urea produces reducing agent ammonia and reduces NOx emissions to nitrogen and water. However, the application of urea SCR technology has many challenges at low temperature conditions, such as deposits formation in the exhaust pipe, lack deNOx performance at low temperature and freezing below -12°C. For preventing deposits formation, aqueous urea solution is hardly injected into exhaust gas stream at temperature below 200°C. The aqueous urea solution used as reducing agent precursor is the main obstacle for achieving high deNOx performances at low temperature conditions. This paper presents a solid SCR technology for control NOx emissions from heavy duty diesel engines.
Technical Paper

Fuel Consumption Analysis and Optimizing of a Heavy Duty Dual Motor Coaxial Series-Parallel Hybrid Lorry under C-WTVC

2017-10-08
2017-01-2359
Abstract Energy saving is becoming one of the most important issues for the next generation of commercial vehicles. The fuel consumption limits for commercial vehicles in China have stepped into the third stage, which is a great challenge for heavy duty commercial vehicles. Hybrid technology provides a promising method to solve this problem, of which the dual motor coaxial series parallel configuration is one of the best options. Compared with parallel configuration, the powertrain can not only operate in pure electric or parallel mode, but also can operate in series mode, which shows better flexibility. In this paper, regulations on test cycle, fuel consumption limits and calculation method of the third stage will be introduced in detail. Then, the quasi-static models of the coaxial series parallel powertrain with/without gearbox under C-WTVC (China worldwide transient vehicle cycle) are built. The control strategies are designed based on engine and motor performance.
Technical Paper

Real World Fleet Test to Determine the Impact of Low Viscosity Engine Oils from Heavy-Duty CNG and Diesel Buses - Part I: Fuel Consumption

2017-10-08
2017-01-2353
Abstract One of the most interesting alternatives to reduce friction losses in the internal combustion engines is the use of low viscosity engine oils. Recently, a new engine oil category focused fuel economy, has been released in North America encouraging the use of these oils in the heavy-duty vehicles’ segment. This paper presents the results of a comparative test where the differences in fuel consumption given by the use of these oils are shown. The test included 48 buses of the urban public fleet of the city of Valencia, Spain. The selected vehicles were of four different bus models, three of them fueled with diesel and the other one with compressed natural gas (CNG). Buses’ fuel consumption was calculated on a daily basis from refueling and GPS mileage. After three oil drain intervals (ODI), the buses using low viscosity engine oils presented a noticeable fuel consumption reduction. These results bear out the suitability of these oils to palliate engine inefficiencies.
Technical Paper

Real World Fleet Test to Determine the Impact of Lower Viscosity Engine Oils from Heavy-Duty CNG and Diesel Buses. Part II: Oil Performance

2017-10-08
2017-01-2351
Abstract Low viscosity engine oils are considered a feasible solution for improving fuel economy in internal combustion engines (ICE). So, the aim of this study was to verify experimentally the performance of low viscosity engine oils regarding their degradation process and possible related engine wear, since the use of low viscosity engine oils could imply higher degradation rates and/or unwanted wear performance. Potential higher wear could result in a reduction in life cycle for the ICE, and higher degradation rates would be translated in a reduction of the oil drain period, both of them non-desired effects. In addition, currently limited data are available regarding “real-world” performance of low viscosity engine oils in a real service fleet.
Technical Paper

Development of CNG/Diesel Dual-Compatible Engine Oil for Heavy-Duty Trucks in Thailand

2017-10-08
2017-01-2350
Abstract In Thailand, most heavy-duty trucks were equipped with diesel engine, while a small portion was equipped with compressed natural gas (CNG) engine. However, in the past few years the number of CNG fuel trucks in Thailand has increased significantly due to the cheaper cost of CNG. In general, the emphasis of heavy-duty diesel engine oil performance is on piston cleanliness and soot handling properties, while thermal and anti-oxidation properties are most critical for CNG engine oil performance. For truck fleet owners who operate both types of trucks, using the inappropriate oil that is not fit-for-purpose can adversely affect engine performance and reduce engine service lifespan under prolonged usage. A novel CNG/diesel engine oil was developed to meet both JASO DH-2 heavy-duty diesel engine oil performance and CNG engine oil performance. The candidate formulation was proved adequately fit for practical use regarding to thermal and anti-oxidation properties.
Technical Paper

Development of Model Based Closed Loop Control Strategy of SCR System for Heavy-Duty Diesel Engines

2017-10-08
2017-01-2383
Abstract Urea selective catalytic reduction (SCR) is a key technology for heavy-duty diesel engines to meet the increasingly stringent nitric oxides (NOx) emission limits of regulations. The urea water solution injection control is critical for urea SCR systems to achieve high NOx conversion efficiency while keeping the ammonia (NH3) slip at a required level. In general, an open loop control strategy is sufficient for SCR systems to satisfy Euro IV and Euro V NOx emission limits. However, for Euro VI emission regulation, advanced control strategy is essential for SCR systems due to its more tightened NOx emission limit and more severe test procedure compared to Euro IV and Euro V. This work proposed an approach to achieve model based closed loop control for SCR systems to meet the Euro VI NOx emission limits. A chemical kinetic model of the SCR catalyst was established and validated to estimate the ammonia storage in the SCR catalyst.
Technical Paper

Development of a DOC+SCR Exhaust Catalyst System for Light Duty Truck (N2 Category) Meeting NS-V Regulation

2017-10-08
2017-01-2368
Abstract The 4JB1 diesel engine originated from Isuzu has large share in the China light duty truck market. However, the tightened NOx emission target enforced by NS-V legislation compared with NS-IV regulatory standard is very challenging for this engine platform which originally adopted the DOC+POC catalyst layout. Furthermore, combustion characterization of this type engine leads to high soluble organic fraction (SOF) content in engine out particulates, which requires the catalysts in the exhaust after-treatment system (ATS) to deliver high SOF conversion efficiency in order to meet the regulation limit for particulate matters (PM). In this paper, an innovative exhaust catalyst layout with DOC+V-SCR is introduced. The front DOC is specially formulated with optimized PGM (Platinum Group Metal) loading which ensures effective SOF oxidation while keeping sulfuric acid and sulfate generation minimal.
Technical Paper

Driving Force Coordinated Control of Separated Axle Hybrid Electric Dump Truck

2017-10-08
2017-01-2462
Abstract Due to the increase of mining production and rising labor costs, manufacturers of construction and mining equipment are engaged in developing large tonnage mining truck with good dynamic performance and high transport efficiency. This paper focuses on the improvement of the dynamic performance of a 52t off-highway dump truck. According to the characteristics of its operating cycle, electric auxiliary drive system is installed in the front axle aiming at improving the utilization rate of ground adhesion. The new all-wheel drive hybrid electric system makes it possible for dump truck transports at a higher velocity. Both the conventional dump truck model and the new all-wheel drive hybrid truck model are built based on the AVL-Cruise platform. Meanwhile, under the premise of enough dynamic performance, fuel consumption can be minimized by collaborative optimization in Isight.
Technical Paper

Application of Reliability Technique for Developing a Test Methodology to Validate the Engine Mounted Components for Off-Road Applications under Vibration

2017-09-29
2017-01-7004
Abstract Vibrational fatigue is a metal fatigue caused by the forced vibrations which are purely random in nature. The phenomenon is predominantly important for the components/systems which are subjected to extreme vibration during its operation. In a vehicle, an engine is the main source of vibration. The vibrational fatigue, therefore, plays a key role in the deterioration of engine mounted components. Multiple test standards and methodologies are available for validating engine mounted parts of an automobile. These might not be appropriate in the case of an off- road vehicle as the vibrational exposure of engine mounted components of an off-road vehicle is entirely different. In the case of an off-road vehicle, the engine mounted components are subjected to a comparatively higher level of vibration for a longer duration of time as compared to the passenger cars.
Technical Paper

Research on Temperature Stability of an Independent Energy Supply Device with Organic Rankine Cycles Based on Hydraulic Retarder

2017-09-22
2017-01-7003
Abstract Hydraulic retarder, as an auxiliary braking device, is widely used in commercial vehicles. Nowadays, the hydraulic retarder’s internal oil is mainly cooled by the coolant circuit directly. It not only aggravates the load of engine cooling system, but also makes the abundant heat energy not be recycled properly. In this study, an independent energy supply device with organic Rankine cycles is applied to solve the problems above. In the structure of this energy supply device, the evaporator’s inlet and outlet is connected in parallel with the oil outlet and inlet of the retarder respectively. A part of oil enters the evaporator to transfer heat with the organic fluid, and the rest of oil enters the oil-water heat exchanger to be cooled by the coolant circuit.
Technical Paper

The Effect of Commercial Vehicle Head-Up Display Reminding System on Driving Safety in Mountainous Area

2017-09-17
2017-01-2500
Abstract Head-up Display (HUD) system can avoid drivers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will use the indicator symbol‘s color and position change to remind drivers to brake or accelerate. Drivers can do driving operation timely and accurately. The system has the advantages of safety, intuition and real-time. The vehicle safe speed is calculated according to the road parameters, like adhesion coefficient and slope, and vehicle parameters, such as vehicle mass and centroid. Then, the appropriate braking operations are obtained by combining the vehicle driving state.
Technical Paper

Brake Guidance System for Commercial Vehicles with Coordinated Friction and Engine Brakes

2017-09-17
2017-01-2508
Abstract Using friction brakes for long time can increase easily its temperature and lower vehicle brake performance in the downhill process. The drivers' hysteretic perception to future driving condition could mislead them to stop untimely the engine brake, and some other auxiliary braking devices are designed to increase the brake power for reduction of the friction brake torque. The decompression engine brake has complex structure and high cost, and the application of eddy current retarder or hydraulic retarder on the commercial vehicles is mainly limited to their cost and mass. In this paper, an innovative brake guidance system for commercial vehicles with coordinated friction brakes and engine brake is introduced to guide the drivers to minimize the use of the friction brakes on the downhill with consideration of future driving conditions, which is aimed at releasing the engine brake potential fully and controlling the friction brake temperature in safe range.
Technical Paper

Estimation and Reduction of Lateral Deviation (Brake Pulling) of a Vehicle due to Difference in Left and Right Wheel Brake Force

2017-09-17
2017-01-2505
Abstract This paper explains a method to estimate and reduce brake pulling of vehicles due to force difference between RH and LH brake during straight ahead braking. One of the cause of brake pulling during straight ahead braking is brake force difference between right and left brakes of front and rear axles. It is challenging to eliminate this unwanted pulling especially during panic braking in shorter wheelbase vehicles having high center of gravity (CG) and drum brake on all wheels. A mathematical model is developed to estimate amount of brake pulling from known parameters like brake force, tire properties, steering geometry, suspension hard points, vehicle CG, scrub radius, castor angle etc. Vehicle tests were conducted to measure amount of brake pulling and close correlation was observed between vehicle test results and derived model.
Technical Paper

Modeling and Optimization of Pneumatic Brake System for Commercial Vehicles by Model Based Design Approach

2017-09-17
2017-01-2493
Abstract Apart from being an active safety system the brake system represents an important aspect of the vehicle dynamics. The vehicle retardation and stopping distance completely depend upon the performance of brake system and the functionality of all components. However, the performance prediction of the entire system is a challenging task especially for a complex configuration such as multi-axial vehicle applications. Furthermore, due to its complexity most often the performance prediction by some methods is limited to static condition. Hence, it is very important to have equivalent mathematical models to predict all performance parameters for a given configuration in all different conditions This paper presents the adopted system modelling approach to model all the elements of the pneumatic brake system such as dual brake valve, relay valve, quick release valve, front and rear brake actuators, foundation brake etc.
Technical Paper

Tuning of Brake Force Distribution for Pickup Truck Vehicle LSPV Brake System During Cornering Maneuver

2017-09-17
2017-01-2491
Abstract Automotive industry has led to constant production innovation among manufactures. This has resulted in the reduction of the life cycle of the design philosophies and design tools. One of the performance factors that have continues to challenge automotive designer is to design and fine tune the braking performance with low cost and short life cycle. Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whosebrake force distribution is variable. Braking force distribution has an important and serious role in thevehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking forcedistribution strategy for articulated vehicles. For this purpose, the virtual optimization process has beenimplemented.
Technical Paper

Brake System Regulations and Standards Review and Comparison Focused on Europe, NA and SA Markets

2017-09-17
2017-01-2534
Summary Considering that the most part of commercial vehicles are equipped with air brakes it is very important assure specific technical requirements for air brake system and its components. In addition, the effects of brake system failure are more critical for commercial vehicles which require more attention on their requirements details. Historically, the development of air brakes technology started on North America and Europe and consequently two strong and distinct resolutions were structured: FMVSS 121 and ECE R.13, respectively. For passenger cars were developed the ECER.13H to harmonize North American and European resolutions. However, for commercial vehicles regional applications, culture and implementation time must be considered. These commercial vehicles peculiarities must be understood and their specific requirements harmonized to attend the global marketing growth.
Technical Paper

Combined Hill Descent Braking Strategy for Heavy Truck in the Featured-Slope

2017-09-17
2017-01-2535
Abstract The continuous braking for the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. It reduces the heavy truck’s braking performance and the braking safety. The engine braking and the hydraulic retarder braking both consume the kinetic energy of the heavy truck and can assist the truck driving in the mountain areas. This research proposes a combined hill descent braking strategy for heavy truck based on the recorded information of the slopes to ensure the braking safety of the heavy truck. The vehicle dynamic model and the brake drum temperature rising model are established to analyze the drum’s temperature variation during the downhill progress of the heavy truck. Then based on the slope information, the combined braking temperature variation is analyzed considering the characteristics of the engine braking, the drum braking and the hydraulic retarder braking.
Technical Paper

Numerical Simulation of the Combustion Process of a High EGR, High Injection Pressure, Heavy Duty Diesel Engine

2017-09-04
2017-24-0009
Abstract To comply with Stage IV emission standard for off-road engines, Kohler Engines has developed the 100kW rated KDI 3.4 liters diesel engine, equipped with DOC and SCR. Based on this engine, a research project in collaboration between Kohler Engines, Ricardo, Denso and Politecnico di Torino was carried out to exploit the potential of new technologies to meet the Stage IV and beyond emission standards. The prototype engine was equipped with a low pressure cooled EGR system, two stage turbocharger, high pressure fuel injection system capable of very high injection pressure and DOC+DPF aftertreatment system. Since the Stage IV emission standard sets a 0.4 g/kWh NOx limit for the steady state test cycle (NRSC), that includes full load operating conditions, the engine must be operated with very high EGR rates (above 30%) at very high load.
Technical Paper

Analysis of Scavenged Pre-Chamber for Light Duty Truck Gas Engine

2017-09-04
2017-24-0095
Abstract An ongoing research and development activities on the scavenged pre-chamber ignition system for an automotive natural gas fueled engine is presented in this paper. The experimental works have been performed in engine laboratory at steady state conditions on a gas engine with 102 mm bore and 120 mm stroke, converted to a single cylinder engine. The in-house designed scavenged pre-chamber is equipped with a spark plug, fuel supply and a miniature pressure sensor for detailed combustion diagnostics. The engine was operated at constant speed, fully open throttle valve and four different fueling modes with or without spark discharge. A partly motored mode allowed direct evaluation of the pre-chamber heat release. The experimental data acquired in this research served as a validation data for the numerical simulations. The performed tests of prototypes and calculations have recently been expanded to include 3-D flow calculations in the Ansys Fluent software.
Technical Paper

Robust DPF Regeneration Control for Cost-Effective Small Commercial Vehicles

2017-09-04
2017-24-0123
Abstract Small commercial vehicles (SCV) with Diesel engines require efficient exhaust aftertreatment systems to reduce the emissions while keeping the fuel consumption and total operating cost as low as possible. To meet current emission legislations in all cases, a DOC and DPF and some NOx treatment device (e,g. lean NOx trap or SCR) are required. Creating a cost-effective SCV also requires keeping the cost for the exhaust aftertreatment system as low as possible because the contribution to total vehicle cost is high. By using more sophisticated and more robust operating strategies and control algorithms, the hardware cost can be reduced. To keep the calibration effort at a low level, it is necessary to apply only algorithms which have a time-efficient calibration procedure. This paper will focus on the active regeneration of the DPF. For safe and efficient DPF regeneration, a very reliable and stable DOC out temperature control is required.
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