Search Results

The basics of propane gas used as an automotive fuel. Topics include what propane is, how it is priced, how fleet obtain it and the basics on propane fueling infrastructure and employee training. Presenter Nathan Ediger, Ferrellgas

Propane autogas, the world?s third most-used engine fuel, powers vehicles, transit buses, and now school buses. Blue Bird has recently launched the Next Generation Vision type C school bus, powered by a ROUSH CleanTech liquid propane autogas fuel system and a Ford 6.8L V10 engine. The bus reduces operating costs by up to 40%, greenhouse gas emissions by up to 24%, and maintains the factory horsepower, torque, and towing capacity ratings. Learn about how school districts are saving over $.30 / mile using this clean, domestically-produced fuel. Presenter Brian Carney, Roush CleanTech.

The presentation by Tucker Perkins, President of CleanFUEL USA, provides important information to those wanting to learn about alternative fuels, specifically propane autogas. CleanFUEL USA provides liquid propane injection engine system for the 6L engine in the GM G4500 cutaway chassis used in many Type A busses. They are also developing an 8L engine in partnership with Freightliner/ThomasBuilt Bus for the Type C bus. This presentation discussed many of the advantages of propane autogas use, such as better economics, lower emissions, and inexpensive infrastructure for the fueling network. Presenter Tucker Perkins, CleanFUEL USA

Who are the people who know the most about the buses in your fleet? They are most likely the operators and the servicing technicians. They are also the key people whose knowledge, level of training and attitude can determine the success or failure of new powertrain technologies. Training and recruitment of both need to be held to a higher standard than we have seen in the past. I will argue that even the culture of those involved in fleet operations needs to be changed. The bar for technical competence and product knowledge needs to be raised for operators and technicians. In return managers should find ways to include them as stakeholders, investing them with both additional responsibility and accountability. This will require greater access to training and recognition of achievement. Where are the busses stored and serviced? Most likely in an all-purpose state/county/municipal service facility servicing a variety of equipment.

A review of the processes that lead to the conclusion that CNG was the best solution for the fleet, including the efforts to gain public support for alternative fuels for school buses. MISD is now home for 42 CNG powered school buses (of 200). The presentation will include training and design tips for safety and smooth operations along with maintenance considerations for using CNG. Alternative fuels, the dilemma of which comes first - refueling station or operational buses ? has an impact on grant approval and funding, bearing discussion of the option of a public/private model. Unlike other alternative fuels, CNG has a national security impact Presenter Charles Stone, Mansfield Indep School Dist

The 9 papers in this technical collection cover fuel injection, combustion, controls, performance and emissions of SI engines fueled with methane based fuels such as natural gas, producer gas, coke oven gas or hydrogen-natural gas blends.

The 5 papers in this technical paper collection cover natural gas engines and vehicles. Topics include: sliding mode control of air path in diesel-dual-fuel engine; optimization of natural gas automotive engine cooling jacket using CFD analysis; waste coke oven gas used as a potential fuel for engines; and more.

Automotive engines are regularly utilized in the material handling market where LPG is often the primary fuel used. When compared to gasoline, the use of gaseous fuels (LPG and CNG) as well as alcohol based fuels, often result in significant increases in valve seat insert (VSI) and valve face wear. This phenomenon is widely recognized and the engine manufacturer is tasked to identify and incorporate appropriate valvetrain material and design features that can meet the ever increasing life expectations of the end-user. Alternate materials are often developed based on laboratory testing – testing that may not represent real world usage. The ultimate goal of the product engineer is to utilize accelerated lab test procedures that can be correlated to field life and field failure mechanisms, and then select appropriate materials/design features that meet the targeted life requirements.

This paper proposes a new returnless LPG fuel supply system designed to increase the efficiency of current LPG engines. With a conventional engine fuel supply system, the fuel pump is driven at a certain speed to pressurize the fuel to an excessive level, and excess fuel that is discharged from the fuel pump but not injected from the injector is returned to the fuel tank via a pressure regulator and a return line. This arrangement keeps the pressure in the fuel supply line at a constant level. Accordingly, during engine idling, fuel cut-off or other times when very little or no fuel is injected from the injector, nearly all the fuel discharged from the fuel pump is returned to the fuel tank via the pressure regulator and return line. Therefore, the energy (electric power) applied to drive the fuel pump is wastefully consumed. Moreover, returning a large amount of excess fuel to the fuel tank can raise the fuel temperature in the tank, causing the fuel to evaporate.

A dual piston Variable Compression Ratio (VCR) engine has been newly developed. This compact VCR system uses the inertia force and hydraulic pressure accompanying the reciprocating motion of the piston to raise and lower the outer piston and switches the compression ratio in two stages. For the torque characteristic enhancement and the knocking prevention when the compression ratio is being switched, it is necessary to carry out engine controls based on accurate compression ratio judgment. In order to accurately judge compression ratio switching timing, a control system employing the Hidden Markov Model (HMM) was used to analyze vibration generated during the compression ratio switching. Also, in order to realize smooth torque characteristics, an ignition timing control system that separately controls each cylinder and simultaneously performs knocking control was constructed.

This study is based on a project which addresses the reduction of CO2 and pollutant emissions of off-road vehicles. For this purpose the use of CNG drive trains in high alpine areas is an interesting alternative to the standard diesel technology. The same SUV with CNG and diesel powertrain has been measured and methodically compared with regard to fuel consumption and exhaust emission performance. These real-world measurements have shown the potential when applying a CNG concept for this utilization. Subsequently, the real-world on-board measurements were compared with the results of a simulation program for SUV off-road performance.

This study evaluates the potential of CNG propulsion systems for long-term operation. For this purpose, light and medium duty vehicles as well as passenger cars with very different service performance were investigated under real-world conditions. The research also includes tests of a vehicle with natural gas and bio-methane to assess the effects of the energy supply on the performance. The demonstration and evaluation of CNG operational fleets with higher mileage provide a sustainable monitoring of clean propulsion systems based on innovative real-world in-car measurements. A benchmarking to the same passenger car with diesel powertrain was done as well. For a consistent comparison of the different test vehicles, the results for each drive test are presented as emission rates versus the mean vehicle speed.

Direct Injection (DI) is believed to be one of the key strategies for maximizing the thermal efficiency of Spark Ignition (SI) engines and meet the ever-tightening emissions regulations. This paper explores the use of Liquefied Petroleum Gas (LPG) liquid phase fuel in a 1.5 liter SI four cylinder gasoline engine with double over head camshafts, four valves per cylinder, and centrally located DI injector. The DI injector is a high pressure, fast actuating injector enabling precise multiple injections of the finely atomized fuel sprays. With DI technology, the injection timing can be set to avoid fuel bypassing the engine during valve overlap into the exhaust system prior to combustion. The fuel vaporization associated with DI reduces combustion chamber and charge temperatures, thereby reducing the tendency for knocking. Fuel atomization quality supports an efficient combustion process.

Long chain alcohols possess major advantages over the currently used ethanol as bio-components for gasoline, including higher energy content, better engine compatibility, and less water solubility. The rapid developments in biofuel technology have made it possible to produce C 4 -C 5 alcohols cost effectively. These higher alcohols could significantly expand the biofuel content and potentially substitute ethanol in future gasoline mixtures. This study characterizes some fundamental properties of a C 5 alcohol, isopentanol, as a fuel for HCCI engines. Wide ranges of engine speed, intake temperature, intake pressure, and equivalence ratio are investigated. Results are presented in comparison with gasoline or ethanol data previously reported. For a given combustion phasing, isopentanol requires lower intake temperatures than gasoline or ethanol at all tested speeds, indicating a higher HCCI reactivity.

The introduction of alternative fuels is crucial to limit greenhouse gases. CNG is regarded as one of the most promising clean fuels given its worldwide availability, its low price and its intrinsic properties (high knocking resistance, low carbon content...). One way to optimize dedicated natural gas engines is to improve the CNG slow burning velocity compared to gasoline fuel and allow lean burn combustion mode. Besides optimization of the combustion chamber design, hydrogen addition to CNG is a promising solution to boost the combustion thanks to its fast burning rate, its wide flammability limits and its low quenching gap. This paper presents an investigation of different methane/hydrogen blends between 0% and 40 vol. % hydrogen ratio for three different combustion modes: stoichiometric, lean-burn and stoichiometric with EGR.

Existing gasoline DI injection equipment has been modified to generate single hole pulsed gas jets. Injection experiments have been performed at combinations of 3 different pressure ratios (2 of which supercritical) respectively 3 different hole geometries (i.e. length to diameter ratios). Injection was into a pressure chamber with optical access. Injection pressures and injector hole geometry were selected to be representative of current and near-future DI natural gas engines. Each injector hole design has been characterized by measuring its discharge coefficient for different Re-levels. Transient jets produced by these injectors have been visualized using planar laser sheet Mie scattering (PLMS). For this the injected gas was seeded with small oil droplets. The corresponding flow field was measured using particle image velocimetry (PIV) laser diagnostics.

Hydrogen engines are required to provide high thermal efficiency and low nitrogen oxide (NOx) emissions. There are many possible combinations of injection pressure, injection timing, ignition timing, lambda and EGR rate that can be used in a direct-injection system for achieving such performance. In this study, several different combinations of injection and ignition timings were classified as possible combustion regimes, and experiments were conducted to make clear the differences in combustion conditions attributable to these timings. Lambda and the EGR rate were also evaluated for achieving the desired performance, and indicated thermal efficiency of over 45% was obtained at IMEP of 0.95 MPa. It was found that a hydrogen engine with a high-pressure direct-injection system has a high potential for improving thermal efficiency and reducing NOx emissions.

Lean burn natural gas engines have high potential in terms of efficiency and NOx emissions in comparison with stoichiometric natural gas engines, and much lower particulate emissions than diesel engines. They are a promising solution to meet the increasingly stringent exhaust emission targets for both light and heavy-duty engines. Partially Stratified-Charge (PSC) is a novel concept which was conceived by prof. Evans (University of British Columbia, Vancouver). This technique allows to further limit pollutant emissions and improve efficiency of an otherwise standard spark-ignition engine fuelled by natural gas, operating with lean air-fuel ratio. The potential of the PSC technique lies in the control of load without throttling by further extending the lean flammability limit.

A newly developed small-sized IES (inductive energy storage) circuit with semiconductor switch at turn-off action is successfully applied to an ignition system of a small gasoline internal combustion engine. This IES circuit can generate repetitive nanosecond pulse discharges. An ignition system using repetitive nanosecond pulse discharges is investigated as an alternative to a conventional spark ignition system. The present study focuses on the extension of the operational limits for lean and diluted combustion using the repetitive nanosecond pulse discharges. First, in order to investigate the flame kernel formation process when the repetitive nanosecond pulse discharges are used, the initial flame kernel is observed using Schlieren photography with a high speed camera. As a result, the flame kernel generated by repetitive pulse discharges is larger than by a conventional ignition system.

In order to extend the HCCI high load operational limit, the effects of the distributions of temperature and fuel concentration on pressure rise rate (dP/dθ) were investigated through theoretical and experimental methods. The Blow-Down Super Charge (BDSC) and the EGR guide parts are employed simultaneously to enhance thermal stratification inside the cylinder. And also, to control the distribution of fuel concentration, direct fuel injection system was used. As a first step, the effect of spatial temperature distribution on maximum pressure rise rate (dP/dθmax) was investigated. The influence of the EGR guide parts on the temperature distribution was investigated using 3-D numerical simulation. Simulation results showed that the temperature difference between high temperature zone and low temperature zone increased by using EGR guide parts together with the BDSC system.