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The current popularity of the Sport Utility Vehicle (SUV) market has led to new developments aiming to increase product performance. Such vehicles pose a significant challenge as they must perform to a high standard over a large variety of road conditions. Previously, emphasis has been placed on off-road ability. However, SUVs are now seen as an alternative to conventional luxury cars, and hence are expected to perform similarly, but without significantly degrading off-road performance. The introduction of a roll control system can achieve body roll levels lower than a conventional sports saloon, whilst improving off-road ability by removing the compromises associated with conventional anti-roll bars. This paper investigates the characteristics of such a system by developing a computer simulation of the vehicle and the associated roll control scheme.

The drag reduction capability of a trailer underbody fairing is investigated using steady Reynolds-averaged Navier-Stokes simulations of a full-scale heavy vehicle traveling at highway speed within a crosswind. The flow field about the vehicle is modeled for two different fairing designs of varying length that yield reductions in the drag coefficient ranging from 0.013 to 0.042. Analysis of the trailer underbody flow field indicates that the fairings decrease the size of a recirculation zone that exists immediately downstream of the tractor drive wheels by providing a surface to which the separated underbody flow can reattach. A comparison of the pressure coefficients across the surface of the fairings demonstrates that the longer fairings produce greater pressure coefficients, hence resulting in a larger reduction in drag than the shorter fairings. One of the fairings is shown to outperform traditional trailer side skirts, which yield a reduction in the drag coefficient of 0.035.

Requirements to future internal combustion engines (ICEs) regarding sustainability and efficiency are continuing to rise while on the other hand, pollutant emission regulations are continuously tightened. Dual-fuel combustion (DFC) of diesel and natural gas is an approach to reduce soot emissions while still profiting from the high efficiency of the diesel combustion process. Using natural gas as the main fuel also helps to reduce carbon dioxide (CO2) emissions due to the favorable C/H-ratio of methane (CH4) as its primary constituent. To reduce both pollutant and greenhouse gas emissions further, diesel can be replaced by an e-fuel. The use of C1-oxygenates – such as polyoxymethylene dimethyl ether (POMDME or “OME”) – as pilot fuel promises to reduce both soot and nitrogen oxide (NOx) emissions. For the present investigation, a 4.5l tractor diesel engine has been converted to a biogas-OME dual-fuel engine. A fully variable valve train has been integrated into the cylinder head.

The effects of humid air on the performance of a naturally aspired three-cylinder diesel engine with low sulfur diesel fuel have been investigated. The additions of the humidity to intake air were performed with a variable steam generator using distilled water, where the relative humidity levels of the intake air were changed from the ambient conditions of 65% to 75% and 95% levels. The tests were performed at two approximate engine output brake horse powers (BHP) of 5.9, and 8.9. Results showed approximately 3.7% and 22.5% reduction in NOx emissions when the relative humidity of the air was increased from 65% (the ambient relative humidity) to 75% and 95% respectively. The addition of the humidity results in increases in the CO, CO₂, and particulate matter (PM), by approximately 3.7, 3.55, 14.9 percents at 5.9 BHP and 22, 2.8, and 9.3 percents at 8.9 BHP. There was no change in the brake specific fuel consumption (BSFC) at 5.9 BHP and about 2.7 increase in the BSFC at 8.9 BHP.

An anticipated increase in diesel fuel demand prompted a study by Energy, Mines and Resources Canada, to assess the effect of synthetic and cracked fuel components on truck cold weather performance. Subsequently, a two-year contract was awarded to Esso Petroleum Canada Research to evaluate the effect of fuel composition on combustion using a 310 hp modern HD engine, and the effect on startup and driveability down to −30°C in four Class 8 trucks.

This paper details results of a numerical and experimental investigation into the relative performance of vaned and vaneless mixed flow turbines for application to medium and heavy-duty diesel engines utilizing pulse exhaust systems. Previous investigations into the impact of nozzle vanes on turbine performance considered only open turbine housings, whereas a majority of medium and heavy-duty diesel engine applications are six-cylinder engines using pulse exhaust systems with divided turbines. The two turbine stages for this investigation were carefully designed to meet the constraints of engines with pulse exhaust systems and to control confounding factors that would undermine the vaned vs vaneless performance comparison. Detailed CFD analysis and turbine dynamometer test results confirm a significant efficiency advantage for the vaned turbine stage under both full and partial admission conditions.

Braking system components generally are safety critical products. Commercial vehicles braking systems are of highly safety critical as they pose a serious threat to life and property. Therefore, a system must be designed and validated to minimize the effects of component failure of these portfolios of products. In order to avoid accidents due to brake failures, this paper mainly focuses on analysis of loss of pneumatic fluid pressure in the components of the braking systems. Leakage of pneumatic fluid pressure through the sealing in braking system is one of the major reasons for the failure of the brakes in the vehicles. The aim of the present study is to simulate the lab failure and improve the design using finite element analysis. Also, the optimized design is validated by experimentally. A finite element model is developed in Ansys Workbench to study the behavior of the sealing ring under assembly conditions.

The deformation of injector components cannot be disregarded as the pressure of the system increases. Deformation directly affects the characteristics of needle movement and injection quantity. In this study, structural deformation of the nozzle, the needle and the control plunger under different pressures is calculated by a simulation model. The value of the deformation of injector components is calculated and the maximum deformation location is also determined. Furthermore, the calculated results indicates that the deformation of the control plunger increases the control chamber volume and the cross-section area between the needle and the needle seat. A MATLAB model is established to The influence of structural deformation on needle movement characteristics and injection quantity is investigate by a numerical model. The results show that the characteristic points of needle movement are delayed and injection quantity increases due to the deformation.

Biodiesel derived from non-edible vegetable oils/tree borne oils hold potential for meeting India's future energy needs by part substitution of Diesel Fuel. This paper investigates performance of 5% blend of commercially available biodiesel (B5) in diesel as fuel for heavy duty vehicles. The test fuel was evaluated on buses with different aspiration technologies viz. naturally aspirated and turbo charged, and the same was compared with neat commercial diesel under different operating conditions like driving cycle, road load simulation (RLS) and wide open throttle (WOT) on chassis dynamometer for power, fuel economy, smoke and soot particle number concentration. Fuel economy was observed to be comparable with B5 in naturally aspirated bus while better fuel economy was observed in case of Turbo charged bus with B5. However, there was a marginal drop in the WOT power (vehicle) with B5 fuel in naturally aspirated bus while the drop was higher with Turbo charged bus.

Primarily, Acoustic performance of muffler are evaluated by insertion loss (IL) and backpressure/restriction. Where Insertion loss is mainly depends upon proper selection of muffler volume, which is proportional to Engine Swept volume, along with internal design configuration, which drives the acoustic principle. Same time, meeting the vehicle level pass by noise (PBN) value as per regulatory norms and system level backpressure as per engine specification sheet are the key evaluating criteria of any good exhaust system. Here, a new Reactive/Reflective type muffler of tiny size have been designed for heavy commercial vehicle application, which is unique in shape and innovative to meet desire performance. In this design, mainly sudden expansion, sudden contraction, flow through perforation and bell-mouth flow phenomenon are used.

Percussive breaking is basically a process in which short duration blows with high force intensity are applied in rapid succession, resulting in rock, concrete or pavement fragmentation. The machine for such a task is the hydraulic breaker which turns the hydraulic energy supplied by a positive displacement pump into mechanical energy as percussions of a piston against a chisel. This work presents the results of experimental tests carried out on a hydraulic breaker to determine its blow impact energy. Then, using these data, theoretical considerations are formulated in order to understand the phenomenon of the tool loading especially at the instant of the impact of the piston against the chisel, leading to the energy release.

The ride dynamics of articulated heavy trucks were studied to assess the benefits of applying electronically controlled suspension elements. Computer simulations were used to compare passive, two-state and continuous semi-active, and fully active suspensions. These results prompted further work to develop a prototype active suspension, operating according to a limited bandwidth strategy, which was tested on a full size, single-wheel-station vibration rig. With the active prototype, root mean square body vertical acceleration was 30% lower than with a production air suspension, during a test simulating travel over a very good road profile. RMS dynamic tyre forces, generated by the active prototype were similarly 20% lower. Mean power consumption during this test was 1.2kW. Further consideration of the limited bandwidth active suspension led to the invention of a substantially passive equivalent.

One of the most promising fuel alternatives for Diesel is Methanol. The fuel is regarded advantageous owing to the easy availability of raw materials for its production, its low cost and high Oxygen content that has potential to reduce emissions of smoke, CO and PM. Methanol as a fuel blend with Diesel is non-viable as they are not readily miscible with each other. This paper expounds the engine performance and emission evaluation of blending Methanol with Diesel by using two methods that aid in overcoming phase separation. The experiments were performed in two stages. In the first stage, investigation of phase stabilization of Methanol in Diesel with suitable additive concentration was performed. This was performed to determine the optimum additive and its concentration for a Methanol share of up to 25% in Diesel-Methanol blends for a stabilization period of 30 days.

The American Society for Testing and Materials (ASTM) D613 test method involves the use of a variable compression ratio CFR F5 engine to determine the cetane number of diesel fuels for use in compression ignition engines. The CFR F5 remains relatively unchanged since its conception, utilizing a swirl prechamber, mechanical jerk fuel pump, and a 10.3 MPa cracking pressure pintle nozzle mechanical injector. Recent efforts to improve the repeatability of the F5 engine involved the development of prototype engines equipped with electronic fuel injection (EFI) and upgraded high-speed instrumentation. These modifications have demonstrated the capability to improve the ASTM D613 precision limits by at least a factor of two. Parameterization of injection strategy has further optimized the test method, producing cycle-to-cycle variations of ignition delay analogous to modern day compression ignition engines.

The main indicators for mobility of a multipurpose wheeled vehicle are the maximum and average technical velocity (it is defined as the distance traveled divided by the time elapsed), and they are mainly determined by power-to-weight ratio and the parameters of the suspension. As our analysis shows, with the increase of the power-toweight ratio of the vehicle and its weight, the growth rate of the velocity is reduced, and after reaching a certain value, the velocity remains almost constant. This is due to the fact that for operating conditions of the multi-purpose wheeled vehicle, movement on roads with different degrees of uneven distribution of the rolling resistance and adhesion, in both transverse and longitudinal directions, is typical.

Diesel exhaust gas aftertreatment systems, which include the selective catalytic reduction (SCR)*) for reduction of NOx are necessary to fulfil the latest legal requirements and are extensively used in the heavy duty (HD) sector. The present paper informs about some results obtained with SCR and with SDPF (a DPF with SCR-coating) on a medium duty research engine Iveco F1C. Beside the limited gaseous emission components NH3, NO2 and N2O were measured. The analysis of nanoparticle emissions was performed with SMPS and CPC. The integration of functions of filtration and NOx-reduction in one element of exhaust aftertreatment system offers several advantages and is widely investigated and considered as a market solution.

Premixed charge compression ignition (PCCI) is a new combustion mode to reduce NOX and soot emission. It requires the optimization of the injection timing and pressure, fuel mass in pilot injection and EGR rate. A 6-cylinder, turbocharged, common rail heavy-duty diesel engine was used in this study. The effect of multiple injection strategies on diesel fuel combustion process, heat release rate, emission and economy of diesel engine is studied. The multiple injection strategies include different EGR level, pilot injection timing, pilot injection mass and post injection timing to achieve the homogeneous compression ignition and lower temperature combustion of diesel engine. Based on endoscope technology, the two-color method was applied to take the flame images in the engine cylinder and obtain soot concentration distribution, to understand the PCCI combustion in diesel engines.

Requirements for constant track and camber have a much greater priority with commercial vehicles than on passenger cars. The target can be reached by a concept of rigid wheel suspension elements. It may cause some problems due to structural noise (vibration transfer). However, on commercial vehicles with elastic suspended driver cabs the noise transfer problem is considered to be manageable by suitable cab suspension elements, on buses a compromise in the tuning has to be found regarding overall damping.

Compared with experimental and theoretical approaches modeling of the scavenging process in a two-stroke engine offers great advantages on account of its simplicity and economy. The clear definition of influencing factors and a better physical interpretation of the model laws governing the flow process help to design the model and to determine the test conditions; the model laws also allow the obtained test results to be transferred to the prototype. A relatively simple and inexpensive liquid model presented enables qualitative observations and quantitative evaluations of different port configurations to be made. For the design of port configurations some recommendations are presented. The short circuiting and instabilities in scavenging test results are also mentioned.

Investigations on valve recession of a commercial vehicle engine inlet valve are done. Failure analysis of inlet valve of a six cylinder commercial vehicle engine developing power of 155 BHP is carried out using the software tools IDEAS and TYCON. Failed engine valves are investigated and concluded that the mode of failure of most of them is valve recession, the possible factors responsible for the valve failure are analyzed including the metallurgical properties of the valve. Combustion force, impact force during closure of the valve are the major factors responsible for valve recession. The valve seat angle is considered in the analysis to find if the change in this angle is helpful in increasing the life of the valve. The prevailing wear mechanism has been shown related to the critical operating conditions such as valve closing velocity, combustion load, valve misalignment relative to the seat insert and seat insert material choice.