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Sintered valve guides are increasingly used in various engine applications due to their superior durability and cost. Typical valve guide materials are low alloyed materials of the type Fe-Cu-C. More severe applications may require higher alloying content. One such application is EGR where the exhaust temperatures are much higher as compared to the conventional automotive valve guide. A new material was developed to work in this harsh environment. The object of this paper is to report development of this material including material properties and durability test results.

Recent studies have shown that hydraulic hybrid drivelines can significantly improve fuel savings for medium weight vehicles on stop-start drive cycles. In a series hydraulic hybrid (SHH) architecture, the conventional mechanical driveline is replaced with a hydraulic driveline that decouples vehicle speed from engine speed. In an effort to increase the design space, this paper explores the use of a fixed displacement checkball piston pump in an SHH driveline. This paper identifies the potential life-limiting components of a fixed displacement checkball piston pump and examines the likelihood of surface fatigue in the check valves themselves. Numerical analysis in ABAQUS software suggests that under worst case operating conditions, cyclic pressure loading will result in low-cycle plastic deformation of check valve surfaces.

Large-scale flows in internal combustion engines directly affect combustion duration and emissions production. These benefits are significant given increasingly stringent emissions and fuel economy requirements. Recent efforts by engine manufacturers to improve in-cylinder flows have focused on the design of specially shaped intake ports. Utility engine manufacturers are limited to simple intake port geometries to reduce the complexity of casting and cost of manufacturing. These constraints create unique flow physics in the engine cylinder in comparison to automotive engines. An experimental study of intake-generated flows was conducted in a four-stroke spark-ignition utility engine. Steady flow and in-cylinder flow measurements were made using three simple intake port geometries at three port orientations. Steady flow measurements were performed to characterize the swirl and tumble-generating capability of the intake ports.

Vehicle rollover has the highest fatality rate among non-collision vehicle crashes. This paper introduces a control scheme with electronically controlled limited slip differential (ELSD) to prevent vehicle rollover. Although the analysis focuses on only an un-tripped and on-road scenario which is a small portion of vehicle rollover accidents, it intends to minimize the dynamic rollover propensity by meeting the National Highway Traffic Safety Administration's (NHTSA) fishhook test. A nonlinear model of planar vehicle dynamics with roll motion is analyzed, and the general characteristics of ELSD are presented. Based on that, a rollover mitigation algorithm is proposed. Finally, a computer simulation demonstrates the effectiveness of the rollover mitigation algorithm.

In amorphous solids such as fused quartz, the failure mechanism under cyclic loading is very different when compared to metals where this failure is attributable to dislocation movement and eventual slip band activity. Standard mechanical fatigue prediction methodologies, S-N or ε-N based, which have been historically developed for metals are rendered inapplicable for this class of material. The fatigue strength of Fused Silica or Fused Quartz (SiO2) material is known to be highly dependent on the stressed area and the surface finish. Stable crack growth in Region II of the V-K curve (Crack growth rate vs Stress intensity factor) is dependent on the competing and transitional effects of temperature and humidity, along that specific section of the stress intensity factor abscissa. Fused glass (under harsh environment conditions) finds usage in Automotive, Marine and Aerospace applications, where stress and load (both static and cyclic) can be severe.

This paper presents the fatigue life assessment work on an engine exhaust valve subject to specified durability test cycles. Using valve stress (or strain) data from finite element methods, material fatigue data, and fatigue prediction models (i.e. SN approach and εN approach based on multi-axial Brown-Miller critical plane method), the valve life estimates were obtained and compared with the observed test data, which were in reasonable agreement. In addition, crack growth approach was used and valve crack propagation life including early stage growth was computed. Finally, a general discussion on three life estimates (i.e. fatigue total life, strain-life and crack growth life) was provided with their governing equation, supported by three real cases.

Using FEM (Finite Element Method) and other analytical approaches, a systematic methodology was developed to predict an engine valve's fatigue life. In this study, a steel (SAE 21-2N) exhaust valve on an engine with a type 2 valve train configuration was used as a test case. Temperature and stress/strain responses of each major event phase of the engine cycle were analytically simulated. CFD models were developed to simulate the exhaust gas flow to generate boundary conditions for a thermal model of the valve. FEM simulations accounted for thermal loads, temperature dependent material properties, thermal stresses, closing impact stresses and combustion load stresses. An estimated fatigue life was calculated using Miner's rule of damage accumulation in conjunction with the Modified Goodman approach for fluctuating stresses. Predicted life results correlated very well with empirical tests.

This paper focuses on modeling of torque-biasing devices of a four-wheel-drive system used for improving vehicle stability and handling performance. The proposed driveline system is based on nominal front-wheel-drive operation with on-demand transfer of torque to the rear. The torque biasing components of the system are an electronically controlled center coupler and a rear electronically controlled limited slip differential. Kinematic modeling of the torque biasing devices is introduced including stage transitions during the locking stage and the unlocking/slipping stage. Analytical proofs of how torque biasing could be used to influence vehicle yaw dynamics are also included in the paper. A yaw control methodology utilizing the biasing devices is proposed. Finally, co-simulation results with Matlab®/Simulink® and CarSim® show the effectiveness of the torque biasing system in achieving yaw stability control.