High Compression Ratio Engine Research Articles

ガソリン高圧噴射を用いた高圧縮比エンジンの燃焼技術（第１報） ―高圧噴射による可能性検討―

ガソリン高圧噴射を用いた高圧縮比エンジンの燃焼技術（第１報） ―高圧噴射による可能性検討―

Combustion Technologies of High Compression Ratio Engine Using High Pressure Gasoline Injection (ThirdReport)

Combustion Technologies of High Compression Ratio Engine Using High Pressure Gasoline Injection (ThirdReport)

Combustion Technologies of High Compression Ratio Engine Using High Pressure Gasoline Injection (Second Report)

Combustion Technologies of High Compression Ratio Engine Using High Pressure Gasoline Injection (Second Report)

Effect of Fuel Octane Numbers on Knocking with High Compression Ratio Engine

Effect of Fuel Octane Numbers on Knocking with High Compression Ratio Engine

Realization and optimization of high compression ratio engine with electromagnetic valve train

Internal combustion engines still play an important role in today’s low carbon society. Further improvement of engine thermal efficiency can be obtained by increasing geometric compression ratio (GCR), but it is limited by the knock especially for gasoline engine. While the application of moving coil electromagnetic valve train (EMVT) on engine intake and exhaust system provides new potential to realize a high compression ratio. Based on this, a later EVO strategy is carried out in this work to enhance the scavenging effect. As a result the residual gas rate and initial temperature in cylinder have a great decrease, which can depress the knock tendency effectively. Then coupled with the utilization of earlier IVC and larger air fuel ratio (AF), the power loss and high fuel consumption caused by the delay of ignition timing can be prevented. Finally, an optimization scheme combining engine thermal model, EMVT model and genetic algorithm program is proposed to optimize the engine GCR and operational parameters. Researches are mainly carried at the typical low speed of 1000 rpm and the results show that the most appropriate GCR is 13.5. With the optimum operational parameters the engine thermal efficiency has an obvious improvement, at full load the torque has not declined and the BSFC decreases by 3.3%; at partial load the BSFC decreases by 3.3–11.8%.

A Study of Combustion Technology for a High Compression Ratio Engine: The Influence of Combustion Chamber Wall Temperature on Knocking

A Study of Combustion Technology for a High Compression Ratio Engine: The Influence of Combustion Chamber Wall Temperature on Knocking

Optimizing Spark Timing of Spark Ignited Ethanol Engine

Alcohol is a good alternate fuel by comparing its performance, availability and renewability against fossil fuels. Ethanol is widely used in IC engines by blending small amount with petroleum fuels, but it is not solely used because its high boiling point and self-ignition temperature makes it difficult to burn in engines because, auto ignition also is not possible because of its high octane number and engine needs spark ignition. In order to overcome this problem we need a spark ignited engine with high compression ratio. So a high compression ratio engine is modified into spark ignited engine. A carburetor with 2mm main jet to supply excess fuel into engine is used in order to compensate its low calorific value. The engine used in this experiment was a single-cylinder direct injection diesel engine with a cylinder bore of 95mm, a stroke of 110 mm and a compression ratio of 13:1. The rated power was 5.3 kW at 1500 rpm. The engine has been tested at different loads for Ethanol against spark timings when piston is at TDC, 5 degree before TDC, 10 degree before TDC, 15 degree before TDC respectively. The optimum spark timing is found among the experimental basis for Ethanol.

Fuel suitability for low temperature combustion in compression ignition engines

The high load operations under low temperature combustion (LTC) strategies are investigated by using diesel, gasoline, n-butanol and ethanol, on the high compression ratio engines. In order to best suit the LTC operations, the fuel delivery strategies are designed in commensurate with fuel properties, for either a single fuel or the dual fuel uses. Engine tests are conducted at load levels of 0.8–1.2MPa of indicated mean effective pressure (IMEP) to study the impact of fuel dispatching ratios, exhaust gas recirculation rates, and intake boost levels, along with the modulation of the diesel injection events. As the baseline tests the single shot diesel injection is firstly investigated under different levels of the boost and injection pressure. The knowledge of the auto-ignition characteristics of the port fuelling is studied with gasoline and applied accordingly to other fuels.The test results indicate that a volatile fuel, when delivered at an intake port, provides an advantage to enable LTC, i.e. suitable to produce a higher homogeneity for the cylinder charge. However, under a high compression ratio, a great deal of efforts is required for a port-dispersed fuel, such as gasoline or n-butanol, to withhold from the premature auto-ignition. The uncontrolled combustion events typically limit the engine load and worsen the soot and nitrogen oxides (NOx) emissions; whereas a lesser reactive fuel i.e. ethanol is preferred for the combustion control at high engine loads. The use of neat ethanol as a main energy supply along with the diesel fuel demonstrates superior performance of efficient combustion; whereupon under an optimized control, ultralow NOx and soot emissions are achieved for an engine load up to 1.7MPa IMEP. When applied with a high-pressure direct injection strategy, an uncommonly tested fuel n-butanol is found more suitable to enable LTC than the diesel fuel.

Empirical Study of Simultaneously Low NOx and Soot Combustion With Diesel and Ethanol Fuels in Diesel Engine

Diesel low temperature combustion (LTC) is capable of producing diesel-like efficiency while emitting ultra-low nitrogen oxides (NOx) and soot emissions. Previous work indicates that well-controlled single-shot injection with exhaust gas recirculation (EGR) is an operative way of achieving diesel LTC from low to mid engine loads. However, as the engine load is increased, demanding intake boost and injection pressure are necessary to suppress high soot emissions during the transition to LTC. The use of volatile fuels such as ethanol is deemed capable of promoting the cylinder charge homogeneity, which helps to overcome the high soot challenge and, thus, potentially expand the engine LTC load range. In this work, LTC investigations were carried out on a high compression ratio (18.2:1) engine. Engine tests were first conducted with diesel and LTC operation at 8 bar indicated mean effective pressure (IMEP) was enabled by sophisticated control of the injection pressure, injection timing, intake boost, and EGR application. The engine performance was characterized as the baseline, and the challenges were identified. Further tests were aimed to improve the engine performance against these baseline results. Experiments were, hence, conducted on the same engine with secondary ethanol port fuelling (PF). Single-shot diesel direct injection (DI) was applied close to top dead center (TDC) to ignite the ethanol and control the combustion phasing. The control sensitivity was studied through injection timing sweeps and EGR sweeps. Additional tests were performed to investigate the ethanol-to-diesel ratio effects on the mixture reactivity and the engine emissions. Engine load was also raised to 16.4 bar IMEP while keeping the simultaneously low NOx and soot emissions. Significant improvement of engine control and emissions was achieved by the DI+PF strategy.

The potential of methanol as a fuel for flex-fuel and dedicated spark-ignition engines

Using light alcohols in spark-ignition engines can improve energy security and offers the prospect of carbon neutral transport. The properties of these fuels enable considerable improvements in engine performance and pollutant emissions. Whereas most experimental studies have focused on ethanol, this paper provides experimental results gathered on various methanol-fuelled engines. A comparison against gasoline on two flex-fuel engines yielded relative efficiency benefits of about 10% for methanol thanks to more isochoric combustion, less pumping, cooling and dissociation losses. Lower combustion temperatures allowed to reduce engine-out NOx by 5–10g/kWh. The CO2 values dropped by more than 10%. Alternative load control strategies, employing mixture richness or exhaust gas recirculation (EGR) to control load while keeping the throttle wide open, were compared on a single cylinder engine. The EGR strategy seems preferable as it allows to increase part load efficiency up to 5% without sacrificing in terms of tailpipe emissions. Finally, this load control strategy of choice was applied to a turbocharged, high compression ratio engine to demonstrate that methanol can be used in dedicated engines with diesel-like efficiencies (up to 42%) and emission levels comparable to or lower than gasoline engines.

Performance characteristics of a glowplug assisted low heat rejection diesel engine using ethanol

Conventional diesel engines with ethanol as fuel are associated with problems due to high self-ignition temperature of the fuel. The hot surface ignition method, wherein a part of the injected fuel is made to touch an electrically heated hot surface (glowplug) for ignition, is an effective way of utilizing ethanol in conventional diesel engines. The purpose of the present study is to investigate the effect of thermal insulation on ethanol fueled compression ignition engine. One of the important ethanol properties to be considered in the high compression ratio engine is the long ignition delay of the fuel, normally characterized by lower cetane number. In the present study, the ignition delay was controlled by partial insulation of the combustion chamber (low heat rejection engine) by plasma spray coating of yttria stabilized zirconia for a thickness of 300 μm. Experiments were carried out on the glowplug assisted engine with and without insulation in order to find out the possible benefits of combustion chamber insulation in ethanol and diesel operation. Highest brake thermal efficiency of 32% was obtained with ethanol fuel by insulating the combustion chamber. Emissions of the unburnt hydrocarbons, oxides of nitrogen and carbon monoxides were higher than that of diesel. But the smoke intensity and was less than that of diesel engine. Volumetric efficiency of the engine was reduced by a maximum of 9% in LHR mode of operation.

5599596 Repulpable hot melt polymer/fatty acid compositions for fibrous products: Sandvick Paul; Verbrugge Calvin J County of Racine, WI, United States assigned to S C Johnson & Son Inc

Using light alcohols in spark-ignition engines can improve energy security and offers the prospect of carbon neutral transport. The properties of these fuels enable considerable improvements in engine performance and pollutant emissions. Whereas most experimental studies have focused on ethanol, this paper provides experimental results gathered on various methanol-fuelled engines. A comparison against gasoline on two flex-fuel engines yielded relative efficiency benefits of about 10% for methanol thanks to more isochoric combustion, less pumping, cooling and dissociation losses. Lower combustion temperatures allowed to reduce engine-out NOx by 5–10 g/kWh. The CO2 values dropped by more than 10%. Alternative load control strategies, employing mixture richness or exhaust gas recirculation (EGR) to control load while keeping the throttle wide open, were compared on a single cylinder engine. The EGR strategy seems preferable as it allows to increase part load efficiency up to 5% without sacrificing in terms of tailpipe emissions. Finally, this load control strategy of choice was applied to a turbocharged, high compression ratio engine to demonstrate that methanol can be used in dedicated engines with diesel-like efficiencies (up to 42%) and emission levels comparable to or lower than gasoline engines.