Search Results

Increased electrification of future heavy-duty engines and vehicles can enable many new technologies to improve efficiency. Electrified oil pumps are one such technology that provides the ability to reduce or turn off the piston oil cooling jets and simultaneously reduce the oil pump flow to account for the reduced flow rate required. This can reduce parasitic losses and improve overall engine efficiency. In order to study the potential impact of reduced oil cooling, a GT-Power engine model prediction of piston temperature was calibrated based on measured piston temperatures from a wireless telemetry system. A simulation was run in which the piston oil cooling was controlled to target a safe piston surface temperature and the resulting reduction in oil cooling was determined. With reduced oil cooling, engine BSFC improved by 0.2-0.8% compared to the baseline with full oil cooling, due to reduced heat transfer from the elevated piston temperatures.

In this study, a high-efficiency heavy-duty diesel engine platform was used to evaluate gasoline compression ignition (GCI) operation. The experiment was carried out using a single-cylinder engine (SCE) of a high compression ratio (22:1). Pump-grade gasoline fuel 87 research octane number (RON) was used throughout engine testing. Injection strategy was established including double and triple injection schemes to optimize both engine efficiency and emissions. Both low-temperature heat release (LTHR) and high-temperature heat release (HTHR) were seen from a two-stage combustion event resulting from the interaction of pilot and main injections. At low load conditions, besides fuel stratification level by pilot/main injection strategy, higher in-cylinder pressure can greatly improve the ignition of 1st stage combustion. As engine load increases, spray-wall interaction becomes more critical on engine efficiency and emissions performance.

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up.

Fluid-Structure Interaction (FSI) simulation approach can be used to simulate a turbocharger. However, this predictive 3D simulation encounters the challenge of a long computational time. The impeller speed can be above 100,000 rpm, and generally a CFD solver limits the maximum movement of the impeller surface per time step. The maximum movement must be a fraction (~0.3) of the cell length, thus the time step will be very small. A Multiple Reference Frame (MRF) approach can reduce computational time by eliminating the need to regenerate the mesh at each time-step to accommodate the moving geometry. A static local reference zone encompassing the impeller is created and the impact of the impeller movement is modeled via a momentum source. However, the MRF approach is not a predictive simulation because the impeller speed must be given by the User. A new simulation approach was introduced that coupled the FSI and MRF approach.

A preliminary case-control study of passenger airbag deployments in frontal crashes (in which a passenger was present) was undertaken. The study was conducted as part of an on-going study of vehicle crash performance and occupant injury at Monash University Accident Research Center (MUARC). The results of this preliminary study suggest that the US experience of fatalities caused by interaction of the passenger with the deploying airbag is not shared in Australia. This is probably because the seat-belt use in this study was 100%. These preliminary results reinforce the view that such airbags should be used as supplementary restraint systems. Further studies are planned to monitor the performance of passenger-airbags and to provide more in-depth analyses when more data become available.

This study presents some results from a case-control study of crashed vehicles equipped with Australian airbag technology (Supplementary Restraint Systems). Vehicles were inspected and occupants interviewed according to the National Accident Sampling System (NASS). Data were available for 383 belted drivers involved in frontal crashes including 253 drivers in airbag-equipped vehicles and 130 drivers in non-airbag vehicles. The analysis revealed reductions in the numbers of injuries to the head, face, chest and neck in the airbag-equipped vehicles although the numbers of upper extremity injuries increased. At higher injury severities (AIS2+) reductions were also observed in injuries to the head, face, neck and chest. Further analysis using Harm as an outcome measure found that the mean Harm per driver (in terms of $AUD) were 60% greater in the non-airbag vehicles compared with the airbag-equipped vehicles.

An in-depth analysis of 200 Abbreviated Injury Score (AIS) 2+ injuries to the lower extremity in frontal collisions has been performed using impairment scales devised by the American Orthopaedic Foot and Ankle Society. The most important subgroup of injuries were identified as ankle/hindfoot injuries. There were 63 such injuries sustained by 53 occupants and these were analyzed in greater depth. Inversion or eversion was identified as the mechanism of injury for 40 % of injuries. However in 70% of these fractures caused by inversion or eversion, minimal or no long term impairment would be expected Injuries associated with significant long-term impairment were attributed to axial forces (i.e. loads perpendicular to the foot). Combined vehicle/injury analysis demonstrated a strong association between toe-pan intrusion and these injuries. Interaction between the occupant and the pedals was identified as a probable injury source in only 25% of injuries to the ankle and hindfoot.

From the authors' files, case examples of thoracolumbar injuries sustained by lap-shoulder belted front seat occupants, in frontal crashes, are presented. Additional cases were found in a review of the clinical literature. The biomechanical literature was reviewed, identifying laboratory studies on thoracolumbar spinal injuries. Suggested mechanisms in the production of these injuries in frontal type car crashes are postulated.

The “seat belt syndrome”, first described in 1961, identified abdominal organ injuries related to the use of the lap belt. Many articles have further documented detailed descriptions of intraabdominal lap belt related trauma. Lumbar spine distractions were later added to this injury list. Lap belt injury literature not infrequently hypothecates that some, if not all, of these seat belt syndrome injuries would be prevented, eliminated, or at least significantly reduced in frequency by the use of lap-shoulder belts. This report, based on data from crash investigations, documents lap-shoulder belt intraabdominal injuries occurring by belt loading alone, without significant intrusion and without significant dynamic flexing of the torso of the restrained front seat occupant.

The effects of child safety seats have been well documented in the medical literature. Scattered throughout the medical literature are individual case reports of cervical injury to children restrained in child restraint systems. A review of the literature is provided identifying previous documented cases. The authors also provide new case details of children with cervical spine injury without head contact. An overview of the growth of the infant and specific details in the cervical spine that may contribute to significant cervical injury without head impact is presented.

Crash injury reduction via lap-shoulder belt use has been well documented. As any interior car component, lap-shoulder belts may be related to injury in certain crashes. Relatively unknown is the fact that cervical fractures or fracture-dislocations to restrained front seat occupants where, in the crash, no head contact was evidenced by both medical records and car inspection. An extensive review of the available world's literature on car crash injuries revealed more than 100 such cases. A review of the NASS 80-88 was also conducted, revealing more examples. Cases from the author's own files are also detailed.