Hydrogen Direct Injection Research Articles

Hydrogen direct injection — A combustion concept for the future

Hydrogen is often cited as the energy carrier of our future. With regard to hydrogen powered internal combustion (IC) engines especially the direct injection (DI) combustion concept offers a lot of opportunities for further improvements.

116 水素の直接噴射による天然ガスエンジンの希薄燃焼促進(OS-1 火花点火機関,バイオ燃料機関)

116 水素の直接噴射による天然ガスエンジンの希薄燃焼促進(OS-1 火花点火機関,バイオ燃料機関)

401 水素直接噴射2ストロークエンジンの検討(エンジンシステム(1))

401 水素直接噴射2ストロークエンジンの検討(エンジンシステム(1))

402 頂部に掃・排気弁を持つ水素直接噴射2サイクル機関の研究(エンジンシステム(1))

402 頂部に掃・排気弁を持つ水素直接噴射2サイクル機関の研究(エンジンシステム(1))

318 直接噴射式水素エンジンの燃焼および性能に関する研究(OS-1 液滴群燃焼,水素燃焼,バイオディーゼル燃料,研究発表講演)

318 直接噴射式水素エンジンの燃焼および性能に関する研究(OS-1 液滴群燃焼,水素燃焼,バイオディーゼル燃料,研究発表講演)

An investigation on the causes of cycle variation in direct injection hydrogen fueled engines

To achieve hydrogen power system with high performance and stable operation, cycle variation of hydrogen-fueled engine with direct injection was evaluated with several variables such as engine speed, injection timing, air–fuel equivalence ratio and spark timing. And the cause of cycle variation was analyzed by using coefficient of variation in combustion period defined in this study. The results showed that the cycle variation of hydrogen-fueled engine is mainly dependent on the early combustion period.

356 水素直接噴射2サイクル機関の検討(応用熱工学(燃焼・熱機関))

356 水素直接噴射2サイクル機関の検討(応用熱工学(燃焼・熱機関))

312 水素直接噴射 2 サイクル機関の検討

312 水素直接噴射 2 サイクル機関の検討

1707 菱形リンク Z クランク機構による水素噴流火花点火機関の燃焼に関する研究

A new hydrogen direct-injection SI engine employing a rhombic link Z-crankshaft mechanism has been developed. The engine was operated for a single combustion cycle. Experimental results show that Z-crankshaft engine keeps relatively high pressure under condition of late spark timing due to piston motion caused by the mechanism. Ignition during injection period results in lower initial pressure rise, which means that rapid combustion of hydrogen can be controled by diffusion burning of hydrogen jet. Neumerical simulation shows that Z-crankshaft engine is useful, in particular, under high speed operating condition for hydrogen combustion because this engine reduces pressure rise with keeping high power when engine speed is increased.

Discussion

A new type of hardware configuration is proposed with direct hydrogen injection combined with gasoline port injection. Different fractions of hydrogen blending were tested under steady-state operating conditions. Independent parameter sweeps were conducted for excess air ratio (λ), ignition timing, and hydrogen fraction. The high laminar burning velocity of the hydrogen caused particle emissions to be insensitive to the ignition timing. With air–fuel mixing at λ = 1.1, the number of nucleation particles decreased and the number of accumulation particles increased with increasing hydrogen fraction, indicating that the temperature affected coagulation more greatly than pyrolysis. With mixing under ultra-lean conditions (λ = 1.2, 1.3, and 1.4), variation of the hydrogen fraction slightly affected the particle number, showing that the critical value for producing particles is the C/O ratio, not the whole mixture equivalence ratio. The decrease of total particle number with increasing λ indicates that this new hardware configuration can take the advantages of lean combustion and avoid the problem of high particle number which is generally associated with this kind of spark-ignition direct-injection engine.

Hydrogen combustion under diesel engine conditions

The autoignition and combustion of hydrogen were investigated in a constant-volume combustion vessel under simulated direct-injection (DI) diesel engine conditions. The parameters varied in the investigation included: the injection pressure and temperature, the orifice diameter, and the ambient gas pressure, temperature and composition. The results show that the ignition delay of hydrogen under DI diesel conditions has a strong, Arrhenius dependence on temperature; however, the dependence on the other parameters examined is small. For gas densities typical of top-dead-center (TDC) in diesel engines, ignition delays of less than 1.0 ms were obtained for gas temperatures greater than 1120 K with oxygen concentrations as low as 5% (by volume). These data confirm that compression ignition of hydrogen is possible in a diesel engine at reasonable TDC conditions. In addition, the results show that DI hydrogen combustion rates are insensitive to reduced oxygen concentrations. The insensitivity of ignition delay and combustion rate to reduced oxygen concentration is significant because it offers the potential for a dramatic reduction in the emission of nitric oxides from a compression-ignited DI hydrogen engine through use of exhaust-gas-recirculation.

Development of a low-no x truck hydrogen engine with high specific power output

The charged hydrogen engine with internal mixture formation as part of the HYPASSE (Hydrogen Powered Automobiles using Seasonal and weekly Surplus of Electricity) project will be presented. With direct hydrogen injection it is possible to solve the problems of hydrogen engines with external mixture formation. Those problems are knocking, glow ignition during compression stroke and backfiring past the intake valve. With the internal mixture formation system, the volumetric efficiency and the power output is equal to that of a diesel engine. To obtain low NO x emissions it is necessary to operate the H 2-engine at excess air ratios λ ⩾ 2 by means of turbocharging. The discrepancy between late high-pressure injection together with diffusion flame propagation and early injection, i.e. to obtain a more homogeneous internal mixture formation, is studied by operating a single-cylinder research engine.

A simple and reliable approach for the direct injection of hydrogen in internal combustion engines at low and medium pressures

Direct injection of hydrogen in internal combustion engines is being recognized as the most appropriate approach to smooth and efficient operation. However, control techniques for the direct injection of hydrogen are all built around the idea of spring-loaded puppet valves, controlled mechanically through rocker arm and camshaft arrangements, or using electromagnetic coils. In both approaches, technical difficulties usually arise because of the relatively complicated multi-component arrangements and because of the excessive temperatures at the top of the cylinder head. To help solve these problems, an assembly comprising a simple hydrogen injector, separated from a simple rotary controller, is introduced in this paper. The hydrogen injector assembly worked in our laboratory, safely and reliably, without the need for springs, coils or cams. Nevertheless, if required, any of these components could be incorporated in a separate controller, away from the high temperature cylinder head. In this way, simple electromagnetic or mechanical controllers could be reliably used.

Further investigations on electronically controlled hydrogen storage and direct injection system for automotive applications

Two components of a recently unveiled hydrogen supply system for automotive use were further investigated: the thermocontrolled tank and the multipoint system for direct hydrogen injection. The behaviour of the thermocontrolled tank has been simulated for use in vehicles at particular driving conditions and heat transfer. The tank insulation requirements and the engine waste heat supply have also been determined. Simulation results will be used for building a prototype tank. The hydrogen injection system has been tested under different engine working conditions. The injectors were placed at various distances from the metering valve to investigate the feasibility of controlling the supply of several injectors through a single metering valve. The test results showed a relatively small impact of the length and volume of the injection pipes on the discharge characteristics of the injectors.

Improved concept of hydrogen on-board storage and supply for automotive applications

Hydrogen is a promising alternative to liquid hydrocarbon fuels. It has particular advantages when injected directly into the cylinder of an internal combustion engine. However, when using hydrogen for automotive applications, large and heavy tanks are required. This problem can be lessened by the proposed thermocontrolled tank concept which uses well insulated high pressure cylinders initially filled with liquid hydrogen which changes phase to compressed gas at a low temperature of 100 to 200 K and high pressure of 300 bar. The gas pressure is maintained during vehicle operation at over 100 bar by the heat transfer to the tank and used for direct hydrogen injection. To increase the heat transfer, the energy of the engine exhaust gases can be used. This concept requires an electronic control based on microprocessor technology with temperature and pressure sensors, as well as electronically actuated valves for the control of heat transfer from the engine exhaust gases to the tank.

Hydrogen injection in two-stroke reciprocating gas engines

A research study in the field of hydrogen-fed engines aims to obtain sufficient maximum power and to avoid any combustion anomaly which might prevent the engine from operating in normal conditions. Thus to investigate the direct injection of hydrogen into the cylinder, with the aim of better combustion with subsequent higher specific outputs, would seem, in the present state of the art, very interesting. During research directed at finding the optimum performance of the engine, three parameters were changed, namely: the quantity of injected hydrogen, total injection timing and timing of ignition before top dead center. This experimental set-up was performed for several injection nozzles using a two-stroke Piaggio engine of 200 cc.

A Universal Standard for Direct Injection Hydrogen Enthalpimetry of Some Common Unsaturated Lipids

Abstract The method of hydrogen enthalpimetry as previously applied to unsaturated and polyunsaturated lipids has employed an authentic sample of each lipid analyte for construction of the enthalpimetric calibration curve. This study shows that individual lipid standards are not necessary for several common naturally-occurring fatty acids, methyl esters and simple triglycerides, each of which can be expressed as equivalent mg of methyl oleate. Data are given for six lipids having from one to nine moles of double bonds per mole of analyte, i. e., from oleic acid to trilinolenin.