Method and device for liquid fuels

摘要

When heating fuels before they are injected, the temperature must not rise above a particular value appropriate to the pressure because otherwise vapour bubbles form. In known devices which heat the fuel by means of heat from the exhaust, the pressure chosen is very high in order to prevent vapour bubbles given the high temperatures and large temperature fluctuations of the heat from the exhaust. High injection pressures lead to a high outlay on construction. Excessively high fuel temperatures are not permissible with applied ignition engines because of knock phenomena. The fuel is heated by means of an auxiliary medium which, when condensed, releases its latent heat to the fuel. By controlling the pressure in the condensation range, it is thus possible to keep the fuel temperature constant within a narrow range irrespective of fluctuations in the fuel flow and of the temperature of the heat source. The heat is added to the fuel on a different temperature level to that of the heat source. Together with an arrangement of an injection pump (9) and a feed pipe (15), it is possible to achieve optimum pressures and temperatures in the fuel during preheating. The method and the device make it possible to use fuel preheating particularly in the case of applied ignition engines and thus provide a means of achieving better mixture formation with a view to improving exhaust emission figures and fuel consumption. <IMAGE>