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An automotive propulsion concept is presented which utilizes liquid nitrogen as the working fluid for an open Rankine cycle. Ambient heat exchangers are used to power an engine that is configured to maximize heat transfer during the expansion stroke. If sufficient heat input during the expansion process can be realized then this cryogenic propulsive system would provide greater automotive ranges and lower operating costs than those of electric vehicles currently being considered for mass production. The feasibility of meeting this engineering challenge has been evaluated and several means of achieving quasi-isothermal expansion are discussed.

Controlled Auto-Ignition (CAI) combustion, also known as HCCI or PCCI, has recently emerged as a viable alternative combustion process to the conventional spark ignition (SI) or compression ignition (CI) process for internal combustion (IC) engines, owing to its potential for high efficiency and extremely low emissions. One of the most effective and practical means of achieving CAI combustion in an engine is to retain or recycle the burnt gases. In order to understand better the effects of recycled burnt gases on CAI combustion, detailed analytical and experimental studies have been carried out. The analytical studies were performed using an engine simulation model with detailed chemical kinetics. The five effects of the recycled burned gases studied include: (1.) Charge heating effect: higher intake charge temperature due to hot burned gases; (2.) Dilution effect: the reduction of oxygen due to the presence of the burned gases; (3.)

An extensive calibration study has been initiated to assess the predictive ability of CFD (Computational Fluid Dynamics) for the aerodynamic design of automotive shapes. Several codes are being checked against a set of detailed wind tunnel measurements on ten car-like shapes. The objective is to assess the ability of numerical analysis to predict the CD (drag coefficient) influence of the rear end configuration. The study also provides a significant base of information for investigating discrepancies between predicted and measured flow fields and for assessing new numerical techniques. This technical report compares STAR-CD predictions to the wind tunnel measurements. The initial results are quite encouraging. Calculated centerline pressure distributions on the front end, underbody and floor compare well for all ten shapes. Wake flow structures are in reasonable agreement for many of the configurations. Drag, lift, and pitching moment trends follow the experimental measurements.

Computational Fluid Dynamics (CFD) has found increasing use by aerodynamicists in recent years. Highly affordable computer hardware coupled with advances in computational techniques and availability of commercial CFD codes support this trend. However, as is true with any computer simulation, there is always a need for comparing aerodynamic CFD predictions extensively to the results measured in wind tunnel experiments. One such calibration study has been initiated by Ford Motor Company to assess the predictive ability of commercially available CFD codes for the aerodynamic design of automobile shapes. Several codes have been checked against a set of detailed wind tunnel measurements on a number of car shapes. The work is being continued to date. This study has provided a significant information base for comparison of predicted and measured flow fields.

A turbocharged lean burn natural gas engine was upgraded to operate on a blend of hydrogen and natural gas (HCNG). Tests were carried out to determine the most suitable H2/NG blend for H2 fractions between 20 and 32 vol%. A 20 vol% H2 content was found to provide the desired benefits when taking into consideration the engine and vehicle performance attributes. A full engine map was developed for the chosen mixture, and was verified over the steady-state AVL8 cycle. In general, the HCNG calibration included operation at higher air-fuel ratios and retarded spark timings. The results indicated that the NOx and NMHC emissions were reduced by 50% and 58% respectively, while the CO and CH4 emissions were slightly reduced. The HCNG engine torque, power and fuel consumption were maintained the same as for the natural gas fuel. The chassis dynamometer transient testing confirmed large NOx reduction of about 56% for HCNG operation.

The purpose of this paper is to outline the effects of oxygen enrichment on the performance of a spark ignited single cylinder Ricardo research engine fueled with natural gas. Substituting gasoline with natural gas, under stoichiometric conditions, brings about a decrease in power output of a dedicated gasoline engine. This reduction in power is quantified in this paper for both fuels under stoichiometric conditions as well as for different fueling rates, for natural gas. Subsequently, the effects of oxygen enrichment are reviewed in terms of: volumetric efficiency, flame propagation velocity, coolant temperature, exhaust gas temperature, spark advance, brake mean effective pressure, brake horsepower. The use of oxygen enriched air results essentially in: 1 a significant increase in brake horsepower, 2 improved lean limits and reduction of spark advance, 3 a lower brake thermal efficiency.

In an effort to reduce CO2 emissions, governments are increasingly mandating the use of various levels of biofuels. While this is strongly supported in principle within the energy and transportation industries, the impact of these mandates on the transport stock’s CO2 emissions and overall operating efficiency has yet to be fully explored. This paper provides information on studies to assess biodiesel influences and effects on engine performance, driveability, emissions and fuel consumption on state-of-the-art Euro IV compliant Toyota Avensis D4-D vehicles with DPNR aftertreatment systems. Two fuel matrices (Phases 1 & 2) were designed to look at the impact of fuel composition on vehicle operation using a wide range of critical parameters such as cetane number, density, distillation and biofuel (FAME) level and type, which can be found within the current global range of Diesel fuel qualities.