HFI (hot fuel injection) injection technology for diesel engines by means of laser pulses

摘要

Injection in diesel engines has developed in recent years towards ever higher injection pressures. The effort required for this is immense and a further development in this direction is not expedient. The present invention is a further development of application no. 102013011670.8 of 12.07.2013 and application no. 102013020678.2 of 5.12.2013, in which the heating of the fuel in the injection valve is effected either by microwave feed, by means of supercap capacitors or by means of battery voltage via a resistor. The further development of laser technology now also makes it possible to heat the fuel by means of a laser beam. Especially the direct diode lasers from Tera Diode are suitable for this purpose. Other laser types are also possible, but for cost reasons currently not recommended. The injection pressure is produced by heating the metered amount of fuel in the heating chamber by means of a laser pulse. The energy pulse is calculated so that it heats the metered amount of fuel by 400 Kelvin. The concomitant expansion of the volume by 33% can not take place in a closed container. An extreme pressure increase is the result. When opening the injector, this pressure abruptly breaks down and the superheated fuel evaporates in the combustion chamber. In doing so, he removes about 0.27 J evaporation energy per mm3 of fuel from the combustion air. The mixing of the vaporized fuel with the compressed air in the combustion chamber ignites the air-gas mixture with minimal ignition delay and ensures an extreme increase in pressure in the combustion chamber.