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Many applications of liquefied petroleum gas (LPG) to commercial vehicles have used their corresponding diesel engine counterparts for their basic architecture. Here a review is made of the application to commercial vehicle operation of a robust 4 L, light-duty, 6-cylinder in-line engine produced by Ford Australia on a unique long-term production line. Since 2000 it has had a dedicated LPG pick-up truck and cab-chassis variant. A sequence of research programs has focused on optimizing this engine for low carbon dioxide (CO₂) emissions. Best results (from steady state engine maps) suggest reductions in CO₂ emissions of over 30% are possible in New European Drive Cycle (NEDC) light-duty tests compared with the base gasoline engine counterpart. This has been achieved through increasing compression ratio to 12, running lean burn (to λ = 1.6) and careful study (through CFD and bench tests) of the injected LPG-air mixing system.

A validated model which attributes fuel consumption to 11 components of a vehicle's energy loss, has been applied to investigate the benefits from improvements in design parameters which can reduce fuel use. Sensitivity analysis of a large, family sized car, gives the ranked order of design variables for improving fuel consumption as: vehicle mass, idle fuel rate or engine friction (or both) and rolling resistance for urban driving. Amongst the remaining parameters aerodynamic drag is lowly ranked but, in highway driving, it ranks first along with vehicle mass and rolling resistance, thus indicating that the proportion of urban to highway driving, which will vary from country to country is important. Driving conditions should be optimised along with vehicle design for best energy conservation and greenhouse gas mitigation.

Several race car competitions seek to limit engine power through a rule that requires all of the engine combustion air passes through a hole of prescribed diameter. As the approach and departure wall shapes to this hole, usually termed orifice or restrictor are not prescribed, there is opportunity for innovation in these shapes to obtain maximum flow and therefore power. This paper reports measurements made for a range of restrictor types including venturis with conical inlets and outlets of various angles and the application of slotted throats of the ‘Dall tube’ type. Although normal venturis have been optimized as subsonic flow measuring devices with minimum pressure losses, at the limit the flow in the throat is sonic and the down stream shocks associated with flow transition from sub-sonic to sonic are best handled with sudden angular changes and the boundary layer minimized by the corner slots between the convergent and divergent cones.

A fleet of 50, 1986-1987 model year cars designed for unleaded gasoline has been tested on the road and on a chassis dynamometer over 5 driving cycles and a wide range of other manoeuvres including steady speeds. It was found that the fuel consumption of this fleet was 17 to 23% (depending on test cycle) less than that of a corresponding fleet to leaded fuelled cars of 1980 model year average. Exhaust emissions were significantly lowered in the range of 45 to 93%. However trend line analysis of the several data sets indicates that the ULG fleet has about 6% higher fuel consumption than would have been expected if there had been a continuing evolution of leaded vehicle technology. The data base produced has applicability to a wide range of planning and design tasks, and those illustrated indicate the effects of speed limit changes and advisory speed signs on fuel consumption and emissions.

The specific power densities and therefore the level of sophistication and costs of FIM-MOTOGP engines 800 cm3 in capacity have reached levels similar to those of the traditionally much more expensive FIA-Formula One engines and some racing developments have no application at all in the development of production bikes. The aim of the paper is therefore to review FIM-MOTOGP engine rules and make recommendations that could reduce costs and make racing more directly relevant to the development of production bikes while enhancing the significant interest in technical innovation by the sports' fans.

Cyclic variability in spark ignition engine combustion, especially at high dilution through lean burn or high EGR rates, places limits on in-cylinder NOx reduction and thermal efficiency. Flame wrinkling, resulting from interactions with turbulence, is a potential source of cyclic variations in turbulence. Previous studies have shown that flame kernels are subject to significant distortions when they are smaller than the integral length scale of turbulence. With the assumption that flame development is not subject to noticeable variations, after it reaches the integral length scale, the authors have shown that turbulent-burning-caused combustion variability can be successfully modeled as a function of laminar flame speed and turbulence intensity. This paper explores the contributions of flame wrinkling to flame kernel growth variation. As the kernel growth problem is complex, this study only explores one of the many aspects of the problem.

A real time energy management (EMS) optimizing algorithm is introduced that performs similar to offline dynamic programming (DP) for parallel HEVs. The EMS and the DP are compared, especially with the addition of a local hill climbing technique, to the example performance prediction of the fuel consumption of a 1.67 tonne large car using a 50 kW Honda Insight engine (representing 65% power reduction from standard) as reference. Then the performance of the vehicle in HEV mode, with a parallel 30 kW motor/generator is examined. The average improvement of this vehicle over five drive cycles from around the world is about 50% reduction in fuel consumption. Next the engine is replaced with an advanced SI turbocharged engine with assisted ignition which returns the performance to that expected of this class of car i.e. 0-100 km/h acceleration time of 7 s. This results in a 14% average reduction in fuel consumption across the five cycles compared with the base Honda engine.

This paper presents some of the modelling and experimental work being carried out at the University of Melbourne, in collaboration with CMC Research, on their new Scotch yoke engine concept. It begins with an overview of the engine, its compactness and friction advantages. The development of a one dimensional ‘squeeze film’ model is outlined and some simulation results are presented for both a motored and fired engine. A novel feature of the model is the introduction of an ‘un-filled factor’ to account for the dynamics of the oil film volume particular to this type of linear bearing. Experimental results are presented to highlight the important features and serve as a means of validating the model predictions. Comparisons show that the squeeze model correlates reasonably well with the experimental data and it is concluded that the current, flat, bearing design works by a predominantly squeeze film mechanism.

The Australian Concept Car was developed with support from a wide range of industry and government sectors. The estimated energy consumption over the vehicle life cycle is presented relative to a typical Australian Upper Medium Class car fleet. Several assumptions are made about the performance of the prototype car, when extrapolating it to a production counterpart for the comparison. Production methods are one area, covered by a survey of suppliers, and particularly in-service fuel use has had to be estimated using validated procedures. Uncertainties exist about the level of recycling at the end of the vehicles projected life after 225,000 km, leading to defined uncertainties. It is concluded that the concept car will have an energy reduction of 15-17.5% and the life cycle CO2 emissions will be reduced by a little less.

Exhaust emission tests were performed on a fleet of vehicles comprising a range of engine technology from leaded fuel control methods to closed loop three-way catalyst meeting 1992 U.S. standards but marketed in Australia. Each vehicle was tested to 5 different driving cycles including the FTP cycles and steady speed driving. Research had shown that for hot-start operation the major driving pattern parameters which influence fuel consumption and exhaust emissions are average speed and PKE (the positive acceleration kinetic energy per unit distance). Plots from analysis of micro-trip fuel use and emissions rates from the test cycles may be presented as contours in PKE. It follows that the micro trip emissions from a range of driving cycles including, regulated e.g. FTP city and unregulated e.g. LA-92, recently developed EPA cycles or from other cities e.g. Bangkok can be superimposed.

The effects on bi-fuel car exhaust emissions, fuel consumption and acceleration performance of a range of LPG fuels has been determined. The LPGs tested included those representing natural gas condensate and oil refineries' products to include a spectrum of C3:C4 and paraffiinic:olefinic mixtures. The overall conclusions are that exhaust emissions from the gaseous fuels for the three-way catalyst equipped cars tested were lower than for gasoline. For all the LPGs, CO2 equivalent emissions are reduced by 7% to 10% or more compared with gasoline. The cars' acceleration performance indicates that there was no sacrifice in acceleration times to various speeds, with any gaseous fuel in these OEM developed cars.

The 2023 FISITA White Paper (for which the author was a contributor) on managing in-service emissions and transportation options, to reduce CO2 (CO2-e or carbon footprint) from the existing vehicle fleet, proposed 6 levers which could be activated to complement the rapid transition to vehicles using only renewable energy sources. Another management opportunity reported here is optimizing the vehicle’s life in-service to minimize the life-cycle CO2 impact of a range of present and upcoming vehicles. This study of the US vehicle fleet has quite different travel and composition characteristics to European (EU27) vehicles. In addition, the embodied CO2 is based on ANL’s GREET data rather than EU27 SimaPro methodology. It is demonstrated that in-service, whole-of-life mileage has a significant influence on the optimum life cycle CO2 for BEVs and H2 fuelled FCEVs, as well as ICEs and PHEVs.