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A fuel-cell-powered vehicle requires a plentiful supply of hydrogen to achieve good performance. This can be produced from methanol via an on-board reformer and gas clean-up unit. Since the reformer can take several minutes to reach its operating temperature, it is initially necessary to provide an alternative power source, such as a battery or ultra-capacitor, in order to drive the vehicle. This paper describes the use of a fuel cell vehicle simulation to predict behavior over a drive cycle from a cold start and to evaluate different warm-up control strategies in terms of performance and fuel efficiency.

This paper presents engine performance and emission results that demonstrate a high degree of correlation between tests performed on a transient engine dynamometer with simulated vehicle characteristics, and test performed on a chassis rolls with a vehicle. The transient testing methodology that has been developed is being used to underpin the transfer of vehicle calibration activity to the testbed.

With current technology, a PEM fuel cell powered vehicle requires a plentiful supply of clean hydrogen to achieve good performance. This can be made available via an on-board methanol reformer. Before the reformer reaches operating temperature it is necessary to obtain energy from an alternative source, such as a battery, in order to power the vehicle. This paper introduces a dynamic model of a methanol reformer fuel cell powered vehicle. The vehicle model is driven over the FTP drive cycle, from a cold start, using various warm up strategies. In this way, different strategies are evaluated in terms of performance and fuel efficiency.

Some advantages may be gained from permitting variation in diesel engines of parameters that are normally fixed, such as mechanical compression ratio. Such an engine could be described as a flexible engine. This paper describes the results of computer modeling work carried out on a hypothetical engine that could be in production by the year 2000 for heavy-duty truck application. The engine--a six-cylinder, in-line, turbocharged, four-stroke engine with air-to-air aftercooling-was modeled using the TRANSENG computer program. It had a swept volume of 8.5 liters and produced 224 kW (300 hp) at 2000 rpm. Modeling work was carried out with a variable geometry compressor, a low-speed optimized compressor, variable compression ratio, and variable valve timing using the Miller cycle. The variable geometry compressor allowed an increase in BMEP of 5 percent and a decrease in fuel consumption of the same amount at rated power.

Homogeneous Charge Compression Ignition (HCCI) combustion can be made to occur in a four-stroke engine with smooth and even combustion under some circumstances. It offers the possibility of light load operation without throttling, thus giving fuel economy like a diesel, in the same engine allowing full load operation with homogeneous charge, thus giving a power density comparable to a gasoline engine. This paper gives results of an experimental program in which the ranges of permissible values of the operating parameters were defined for HCCI operation of a four-stroke engine. It was found that HCCI required high exhaust gas recirculation (EGR) rates (in the range of 13 to 33 percent) and high intake temperatures (greater than 370°C). Under the right conditions HCCI combustion produced fuel economy results comparable with a D.I. diesel engine (ISFC in the range 180 to 200 g/kWh).

The paper gives a general overview of the state-of-the-art in low heat rejection (LHR) engines. It also gives experimental results obtained at SwRI with a single-cylinder research engine using an electrically heated cylinder liner to simulate LHR operation and examine the effects of increased liner temperature. It was concluded that the improvement in fuel economy from LHR operation is negligible in naturally-aspirated (NA) engines, about 7 percent in turbocharged (TC) engines and about 15 percent in turbocompound (TCO) engines. LHR operation reduces power in NA engines only. It increases NOx emissions by around 15 percent, but reduces HC and CO emissions. LHR operation offers benefits in the reduction of noise and smoke, and in operation on low cetane fuels. Much more research is needed to overcome the practical problems before LHR engines can be put into production.

Toward the end of this century the shortfall of supply below demand of the products of natural crude oil will become severe. Research is already well under way to provide alternative fuels for spark-ignition engines which will be independent of natural crude oil. These include fuels from oil shales and tar sands, as well as synthetic fuels, alcohols, and gases; sources include coal, natural gas and biological origins. These fuels will cost two to three times as much in real terms as gasoline from oil does now, so an even stronger emphasis on fuel economy will be required. Most of these alternative fuels are more suited to the spark-ignition engine than the compression-ignition engine, and this paper predicts that the changeover to them will cause an increase rather than a decrease in the market penetration of the spark-ignition engine.

A compact passenger car was modified to allow operation with up to six manual gear ratios and up to 35.4 mile/h per 1000 rev/min. Fuel consumption tests were carried out at steady state conditions, over the U.S. Federal urban drive cycle and on the road. Fuel economy improvements of up to 24% were achieved on the road, and up to 25% on the chassis dynamometer over the urban cycle, confirming computer predictions.

A study has been carried out, aimed at improving passenger car economy by better matching of the engine and transmission. Vehicle simulation was carried out which showed that a reduction of 25% in fuel consumed is theoretically possible. Engine development was carried out which showed that the results of valve timing changes were small, but the four valve cylinder head tested gave better economy than the two valve cylinder head over the whole engine operating range. Resulting from a study of transmissions, it is recommended that two wide span transmissions be developed - a six speed semi automatic and an eight speed fully automatic.

A research programme has been carried out to investigate the effects of operating gasoline engines with different combustion systems. The results showed that at high compression ratios (13:1) compact combustion chambers allowed an increase in compression ratio of between 1 and 2½ numbers for a given fuel quality compared to conventional designs. Fuel economy benefits of about 10% could be achieved by using high ratio compact chambers and lean operation.

It has been shown by calculation that, for given engine operating conditions, there should be an optimum rate of combustion for minimum Nox emissions from spark ignited engines. This paper gives experimental results from a single cylinder engine which confirm the theory, and show that, for a particular engine, the normal combustion rate needed reducing at zero EGR and increasing at high EGR rates, in opposition to its natural tendency to decrease. The effect on economy was a small loss at zero EGR, but an appreciable improvement at high EGR. Cyclic variation and octane requirement studies are also included.