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The work presented here seeks to compare different means of providing scavenging systems for an automotive 2-stroke engine. It follows on from previous work solely investigating uniflow scavenging systems, and aims to provide context for the results discovered there as well as to assess the benefits of a new scavenging system: the reverse-uniflow sleeve-valve. For the study the general performance of the engine was taken to be suitable to power a medium-duty truck, and all of the concepts discussed here were compared in terms of indicated fuel consumption for the same cylinder swept volume using a one-dimensional engine simulation package. In order to investigate the sleeve-valve designs layout drawings and analysis of the Rolls-Royce Crecy-type sleeve had to be undertaken.

Manufacturers of heavy-duty diesel engines are facing increasingly stringent, emission standards. These standards have motivated new research efforts towards improving the performance of diesel engines. The objective of the present program is to develop a comprehensive analytical model of the diesel combustion process that can be used to explore the influence of design changes. This will enable industry to predict the effect of these changes on engine performance and emissions. A major benefit of the successful implementation of such models is that engine development time and costs would be reduced through their use. The computer model is based on the three-dimensional KIVA-II code, with state-of-the-art submodels for spray atomization, drop breakup / coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, and soot and radiation.

Three-dimensional transient simulation was performed and an autoignition model was implemented to predict knock occurrence and autoignition site in a heavy-duty liquefied petroleum gas (LPG) engine. A flame area evolution (FAE) premixed combustion model was applied to simulate flame propagation. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the result of this modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed to detect knock occurrence, flame arrival angle, and autoignition site. The simulation result shows good agreement with engine experiments. It also provides much information about in-cylinder phenomena and some ways to reduce knocking tendency. This knock simulation can be used as a development tool of engine design.

A quasi-dimensional computer simulation model is presented to simulate the thermodynamic and chemical processes occurring within a spark ignition engine during compression, combustion and expansion based upon the laws of thermodynamics and the theory of equilibrium. A two-zone combustion model, with a spherically expanding flame front originating from the spark location, is applied. The flame speed is calculated by the application of a turbulent entrainment propagation model. A simplified theory for the prediction of in-cylinder charge motion is proposed which calculates the mean turbulence intensity and scale at any time during the closed cycle. It is then used to describe both heat transfer and turbulent flame propagation. The model has been designed specifically for the two-stroke cycle engine and facilitates seven of the most common combustion chamber geometries. The fundamental theory is nevertheless applicable to any four-stroke cycle engine.

This paper describes a general purpose computer graphics interface for performing detailed two- and three-dimensional studies involving the dynamic response of humans and vehicles during the pre-crash, crash and post-crash phases of a motor vehicle accident. Specifications are provided for human, vehicle and environment models which can be constructed and analyzed using the interface. The requirements of analysis methods which may be incorporated into the interface are examined, and several examples are provided. Finally, the paper illustrates how the interface is used for creating high-level animations to view the resulting human and/or vehicle motion on various output devices such as computer displays, printers, plotters and video tape recorders.

Trucks can carry heavy load and when applying the brakes during for example a mountain downhill or for an abrupt stop, the brake temperatures can rise significantly. Elevated temperatures in the drum brake region can reduce the braking efficiency or can even cause the brake system to fail, catch fire or even break. It therefore needs to be designed such to be able to transfer the heat out of its system by convection, conduction and/or radiation. All three heat transfer modes play an important role since the drum brakes of trucks are not much exposed to external airflow, a significant difference from disk brakes of passenger cars analyzed in previous studies. This makes it a complex heat transfer problem which is not easy to understand. Numerical methods provide insight by visualization of the different heat transfer modes. Presented is a numerical method that simulates the transient heat transfer of a truck drum brake system cooldown at constant driving speed.

In order to fulfill the technical requirements of a high-efficiency low-emissions off-road horizontal diesel engine, a unique design is proposed and optimized in this paper for the cooling water jacket structure with a forced-cooling closed-loop cooling system. The cooling water flow rate, temperature, and pressure at the inlet and several other critical locations of the cooling water jacket were measured and analyzed at different engine operating conditions for the water jacket designs. A numerical simulation model of the coolant flow and the cooling system was built and used to analyze the thermal/fluid characteristics of the coolant flow in the water jacket. The impact of different structural and packaging design parameters on coolant flow and heat transfer was investigated. The design deficiency of an original (earlier) design of the water jacket was pointed out and an improved design was proposed.

Stringent global emissions legislations demand effective NOx reduction strategies for both the engine as well as the aftertreatment. Diesel applications have previously applied Lean NOx Catalysts (LNCs) [1, 2], but their reduction efficiency and longevity have been far less than that of the competing ammonia-based SCR systems, such as urea [3]. A catalyst has been developed to significantly reduce NOx emissions, approaching 60% with ULSD and exceeding 95% with E85. Both thermal and sulfur aging are applied, as well as on-engine aging, illustrating resilient performance to accommodate necessary life requirements. A robust system is developed to introduce both ULSD from the vehicle's tank as well as E85 (up to 85% ethanol with the balance being gasoline) from a moderately sized supplemental tank, enabling extended mileage service intervals to replenish the reductant, as compared with urea, particularly when coupled with an engine-out based NOx reduction technology, such as EGR.

Planning for charging in transport missions is vital when commercial long-haul vehicles are to be electrified. In this planning, accurate range prediction is essential so the trucks reach their destinations as planned. The rolling resistance significantly influences truck energy consumption, often considered a simple constant or a function of vehicle speed only. This is, however, a gross simplification, especially as the tire temperature has a significant impact. At 80 km/h, a cold tire can have three times higher rolling resistance than a warm tire. A temperature-dependent rolling resistance model is proposed. The model is based on thermal networks for the temperature at four places around the tire. The model is tuned and validated using rolling resistance, tire shoulder, and tire apex temperature measurements with a truck in a climate wind tunnel with ambient temperatures ranging from -30 to 25 °C at an 80 km/h constant speed.

In the near future, GM will introduce a new product to the marketplace. The vehicle is a full-size, four-door utility vehicle based on its current C/K full-size truck product line. This new vehicle is smaller than the current Suburban and does not provide room for a third seat. It is expected that this utility will supplement the small truck four-door utility and create a new market niche with its unique size and features. The process used to design, develop and validate the new product in an aggressive 93-week time frame, is the subject of this paper.

As a non-predictive model of the scavenging process, a generalized thermodynamic model has been suggested. This model can give a thermodynamic description for any possible scavenging process. Having specified a history of the scavenging process, this model is suitable for all scavenging systems including cross, loop and uniflow scavenging schemes. For the simplified isobaric and isochoric model with respectively constant coefficients of intake and discharge proportions during different scavengine phases, analytical solutions for this model have been obtained. From these, all existing models with the isobaric and isochoric assumptions can be derived.

A 13 L HD diesel engine was converted to run as a flame propagation engine using the HEDGE™ Dual-Fuel concept. This concept consists of pre-mixed gasoline ignited by a small amount of diesel fuel - i.e., a diesel micropilot. Due to the large bore size and relatively high compression ratio for a pre-mixed combustion engine, high levels of cooled EGR were used to suppress knock and reduce the engine-out emissions of the oxides of nitrogen and particulates. Previous work had indicated that the boosting of high dilution engines challenges most modern turbocharging systems, so phase I of the project consisted of extensive simulation efforts to identify an EGR configuration that would allow for high levels of EGR flow along the lug curve while minimizing pumping losses and combustion instabilities from excessive backpressure. A potential solution that provided adequate BTE potential was consisted of dual loop EGR systems to simultaneously flow high pressure and low pressure loop EGR.

A lightweight design method of vehicle dash insulators is proposed and investigated in this paper. The lightweight dash insulator, which is composed of double layers of cotton felt with different density and a layer of polyethylene (PE) film and has 55% decrease in weight, is developed and applied in a passenger car, instead of the traditional “heavy layer-soft layer” dash insulator. To evaluate the NVH performance of the lightweight dash insulator, the noise reduction (NR) level index is calculated by using SEA simulation and the sound pressure level and sound qualities in the vehicle are tested under the driving conditions for wide open throttle acceleration in third gear and 60km/h cruising in fourth gear. The simulation and test results show that the vehicle with the lightweight dash insulator has better NVH performance.

A lumped-parameter thermal network model, based on the analogy between heat transfer and electric current flow, is presented for hybrid powertrain cooling systems. In order to optimally select the powertrain components that are commercially viable and meet performance, emission, fuel economy and life targets, it is necessary to consider the influence of cooling architecture. Especially in electric and hybrid vehicles, temperature monitoring is important to increase power and torque utilization while preventing thermal damages. Detailed thermal models such as FEA and CFD are considered for component level assessments as they can locate thermal hotspots and identify possible design changes needed. However, for the system level analysis, the detailed numerical models are not suitable due to the requirement of high computation effort.

In India, around 70 million people travel by public transport buses. With rising air pollution across cities, there is a need to safeguard passengers from inhaling polluted air. Contaminants in such polluted air could be fine to coarse dust (2.5 micron to 100 micron), exhaust gases (oxide of sulphur, nitrogen and carbon), total volatile organic compounds, bacteria and viruses arising out of covid-19 pandemic. Passengers commuting in buses are continuously inhaling air that is re-circulating through the Air Conditioning system (AC) and also comes in contact with multiple co-passengers and touch points. This air potentially carries a high dose of contaminants and inhalation of such air can lead to health issues. Vehicle manufacturers intend to provide clean air inside the vehicle cabin by configuring various Air Purification systems (AP) which reduce air contaminants in the closed space of a cabin.

A patent pending microprocessor controller, detection algorithm and low cost sensor have been developed to accurately detect a refrigerant low charge state in mobile air conditioning systems. The device is intended to prevent damage to the air conditioning system compressor and was designed primarily for truck and bus applications although the principles may also be applied to automotive, agricultural, construction, mining equipment and stationary HVAC applications. The system uses a single, thermistor based refrigerant charge sensor, an optional high pressure transducer and a microprocessor controlled electronics module coupled with standard air conditioning system components to detect the presence or lack of refrigerant in the A/C circuit.

The paper describes a compact low cost engine simulator used in a diagnostic system for marine diesel engines. It models normal and certain abnormal behaviour modes and can be used with an intelligent health monitor for fault recognition. The mathematical model used is the highly detailed ‘filling and emptying’ method wherein the first order equations which result from the principles of energy, mass and momentum conservation are solved on a degree by degree basis. This allows a number of faults to be simulated, for example, those which affect the airflow such as leaking intake or exhaust manifolds or fouled turbomachines or intercoolers. A multiprocessor Motorola 68020 computer system is used to allow concurrent solution of the equations for each of the thermodynamic control volumes.

Liquid Crystal Display is in the process of achieving the supreme position as an automotive instrument panel; it will replace all other existing automotive displays on dashboards. However, a number of problems on technical support remain to be solved. Focused the most among them is the strong demand of a highly reliable connection method. The new connection technique by soldering was presented in the previous paper. This paper describes the reliability and fabrication process of the new connection and its application to Driver IC on flexible P.C.B. and Chip on Glass instrument panels.

To reduce heat transfer between hot gas and cavity wall, thin Zirconia (ZrO2) layer (0.5mm) on the cavity surface of a forged steel piston was firstly formed by thermal spray coating aiming higher surface temperature swing precisely synchronized with flame temperature near the wall resulting in the reduction of temperature difference. However, no apparent difference in the heat loss was analyzed. To find out the reason why the heat loss was not so improved, direct observation of flame impingement to the cavity wall was carried out with the top view visualization technique, for which one of the exhaust valves was modified to a sapphire window. Local flame behavior very close to the wall was compared by macrophotography. Numerical analysis by utilizing a three-dimensional simulation was also carried out to investigate the effect of several parameters on the heat transfer coefficient.

Presenting a brand new approach to heat exchangers for engines, transmissions, hydraulic systems, etc. This new heat exchanger is made of only two pieces of circular extruded aluminum profiles: Core and shell. No soldering: The core and the shell is assembled by a minimum of automated work. In an oil to water cooling application, the active surface on the oil side of the core is enlarged by fins 0.2 mm thick, 0.3 mm spacing, and 3 mm high. The fins are made in unique production machines and enlarge the active surface area approximately five times compared to a conventional heat exchanger of the same dimensions. The principle utilizes the low pressure drop at laminar flow and avoids the disadvantage of low heat transfer after a certain laminar flow length. The result is approximately three times higher oil heat dissipation, combined with very low oil pressure drop, compared to conventional technique.