JPS5936701Y2 - Diesel engine cold starting device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a low temperature starting device for a Cummins type diesel engine.

Generally, when starting a diesel engine equipped with a fuel injection pump at a low temperature, it is necessary to increase the ranking rotation speed required for initial ignition compared to a Bosch type diesel engine.

This is because the injector artificial fuel pressure is low during low speed rotation, resulting in insufficient fuel injection amount and deterioration of spray characteristics due to a drop in injection pressure.

As a result, it had a higher low-temperature starting limit than a Bosch diesel engine, and required a large-capacity battery and starter to start at low temperatures.

This idea was made with the aim of improving this problem. An electric auxiliary pump was installed in parallel with the fuel injection pump, and this auxiliary pump was activated only when starting at low temperatures to increase the injector's artificial fuel pressure, making it easier to start. The present invention aims to provide a low-temperature starting device for diesel engines.

This invention will be described in detail below with reference to an illustrated embodiment.

In the figure, 1 is the main body of the Cummins diesel engine.
Each combustion chamber (not shown) is equipped with an injector 2,
Fuel introduced from a tank 3 via a filter 4 is supplied to these injectors 2 via a fuel injection pump 5, and surplus fuel is circulated to the tank 3 via a return pipe 6.

Reference numeral 7 denotes an electric auxiliary pump connected in parallel with the fuel injection pump 5 through a pipe 8. A part of the outlet side pipe 8 of the electric auxiliary pump 7 is provided with an electric auxiliary pump that opens when the electric auxiliary pump 7 is activated. A solenoid valve 9 is interposed so that the fuel discharged from the auxiliary pump 7 is combined with the discharge pressure of the fuel injection pump 5.

The electric auxiliary pump 7 and the solenoid valve are electrically connected to a start contact of a key switch (not shown),
When starting the engine body 1 at a low temperature, the electric auxiliary pump 7 and the solenoid valve 9 are energized by switching the key switch from the warm position to the star 1 position after preheating.

Note that the electromagnetic valve 9 may be a check valve that allows flow only from the electric auxiliary pump 7 side to the injector 2 side.

This idea has been explained in detail above, so that when starting the engine body 1 at low temperature, the electric auxiliary pump 7 is also started by operating the key switch to the starting position after preheating. Since the discharge pressure is combined with the discharge pressure of the fuel injection pump 5 and supplied to the injector 2, the injector artificial fuel pressure at low speed rotation increases and the atomization of the injected fuel is promoted, so that the engine can be easily heated even at low temperatures. The main body 1 can now be started.

This improves low-temperature starting performance, and also makes starting easier, allowing the use of a small-capacity battery and starter, making it economical.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of this invention. 1 is the engine body, 2 is an injector, 5 is fire fuel injection pump, 7 is an electric auxiliary pump.

Claims (1)

[Scope of utility model registration request] In a Cummins type diesel engine, fuel is supplied from a fuel injection pump 5 to an injector 2 provided in each combustion chamber of the engine body 1.The fuel injection pump 5 is activated at a low temperature start to increase the discharge pressure above the above level. A low-temperature starting device for a diesel engine, which is formed by connecting an electric auxiliary pump 7 in parallel to join the discharge pressure of a fuel injection pump 5.