JPS593156A - Device for assisting engine starting operation - Google Patents

Abstract

PURPOSE:To improve engine starting performance, by storing hydrocarbon fuel formed by cracking of liquid fuel at lower boiling point during engine operation, reducing the pressure of the hydrocarbon fuel to gasify same upon engine starting, and supply such a gasified fuel. CONSTITUTION:When hydrocarbon fuel level in a reservoir 14 becomes lower than a preset level during engine operation, current is conducted through a controller 20 to a heater 28 in accordance with an output from a level sensor 43, and at the same time, solenoid valve 12 is opened to supply liquid fuel such as gas oil to a cracking device 13. The liquid fuel is heated in a reaction chamber 25 filled with a catalyst 24 by the heater 28 to be cracked, thereby forming a hydrocarbon fuel of lower boiling point fraction such as propane, butane or the like. The gas fuel is fed through a piping 11, in which the fuel is cooled, to the reservoir 14, where it is condensed and liquefied for storing. Thus, the liquefied fuel is injected from a nozzle 17 upon engine starting, and is ignited for combustion by an ignition plug 18 for heating intaken air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starting assist device for a diesel engine or the like.

Engines that use low-volatility fuel (light oil), such as diesel engines, are equipped with some kind of starting aid device to improve starting performance in cold weather.

A conventional starting assist device of this type is shown in FIG. 1 (see Utility Model Application No. 57-15985).

To explain this based on the figure, an intake heater 2 is attached to an intake manifold 1 of an engine, and a fuel filter 5. The fuel introduced through the auxiliary tank 6 with the needle pulp 6a is combusted, and the combustion heat heats the intake air, thereby achieving a unique start-up. Note that 7 is a heater activation switch interposed between the intake heater 2 and the battery 8.

Such an intake heater-type starting assist device has advantages over a glow plug-type device, such as superior low-temperature starting performance and superior engine fuel efficiency since there are no protrusions in the combustion chamber.

However, in such conventional intake heater type starting aid devices, since liquid fuel is combusted in the intake manifold, it takes time for preheating, evaporation, and ignition, and it takes 10 to 10 minutes to start the engine.
A problem occurred in that it was necessary to wait about 5 seconds.

The present invention has been made in view of these conventional problems, and involves storing low boiling point hydrocarbon fuel produced by decomposing liquid fuel during engine operation, and using the stored fuel when starting the engine. It is an object of the present invention to provide a starting assist device that solves the above-mentioned problems by reducing the pressure, gasifying the gas, supplying the gas into the intake passage, and igniting and combusting it.

The present invention will be explained below based on illustrated embodiments.

In FIG. 2 showing one embodiment, a pipe 11 whose upstream end is connected to a fuel tank (not shown) includes, in order from the upstream side, a solenoid valve 12 and a decomposer that decomposes fuel to produce low-boiling hydrocarbon fuel. 13 is interposed, and the other end is connected to a gas inlet of a reservoir 14 for storing cracked gas. The reservoir 14 is attached by fixing the outlet bottom wall portion, which is integrally connected with the solenoid valve 15, to the wall of the intake manifold 16. A combustor 19 in which a gas nozzle 17 connected to the gas outlet of the reservoir 14 and a heat generating part 18a of a spark plug 18 attached to the wall of the intake manifold 16 adjacent to the reservoir 14 are fixed together is installed inside the intake manifold 16. It is installed in the intake passage.

FIG. 3 shows the internal structure of the decomposer 13. In the figure, a top cover 21 and a bottom cover 22 are connected to the top and bottom opening surfaces of the inner and outer double cylinders, respectively, and a catalyst 24 (if the fuel is light oil, the catalyst 24 is a zeolite
Registered trademark; Na12 ((AIO) (SiO)
)・27HO etc.) are desirable. ) filled reaction layer 2
5 is formed, and an annular preheating passage portion 27 is formed between the inner cylinder 23 and the outer cylinder 26. In addition, the top cover 21 includes
A heater 28 is attached, and its heat generating portion 28a is introduced into the reaction layer 25. On the other hand, the bottom cover 22 is formed with a fuel port 29 that connects to the upstream pipe 11 and a passage 3o that communicates the inlet 29 with the preheating passage section 27, as well as a fuel outlet 32 that connects to the downstream pipe 11. A passage 33 communicating the reaction layer 25 and the fuel outlet 32 is formed. Note that the reaction layer 25 and the preheating passage section 27 communicate with each other through a hole 23a opened at the upper end of the inner cylinder 23.

In such a configuration, the fuel introduced from the fuel population 29 flows through the passageway 30. After being vaporized through the preheating passage section 27, it flows into the reaction layer 25 through the hole 23a, where the low boiling point hydrocarbon fuel is decomposed and produced, and then passed through the passage 33. The fuel flows out through the fuel outlet 32 into the downstream piping 11 .

FIG. 4 also shows the internal structure of the reservoir 14, in which a gas port 42 is opened on the top wall of the storage chamber 41, and the liquid level of the low-boiling hydrocarbon fuel condensate stored at high pressure in the storage chamber 41. A level sensor 43 is attached to detect the level. The flange portion 44 connected to the bottom of the storage chamber 41 has the storage chamber 4
A passage 46 connecting the bottom wall 1 and the gas outlet 45 via the electromagnetic valve 15 is formed, and the lower end of a pipe 47 whose upper end opens into the space above the condensate in the storage chamber 41 is fixed, and A passage 49 is formed that connects the lower end of the pipe 47 and the gas outlet 45 via a relief valve 48.

In FIG. 2, an engine starting signal a, an engine rotational speed signal and a signal from the level sensor 43 are inputted from the controller 20, and the electromagnetic valves 12, 15, heaters 28, and spark plugs 18 are input as described later. It is designed to control the operation of the

Next, the action will be explained.

During engine operation, a solenoid valve 15 integrated with the Lisano X14 is closed and the spark plug 18 is deactivated in response to a command from the controller 20 in response to an engine rotational speed signal. If the amount of low-boiling hydrocarbon fuel stored in the reservoir 14 is less than the set value, the heater 28 is energized and activated by a command from the controller 20 in response to a signal from the level sensor 43. The solenoid valve 12 is opened and liquid fuel such as light oil is supplied to the decomposer 28. The fuel is fed to the reaction bed 2 filled with a catalyst 24.
Propane is heated to approximately 470°C by the heater 28 in the interior of the propane.

It is produced by the decomposition of low-boiling hydrocarbon fuels such as butane.

The gaseous fuel thus generated passes through the pipe 11 and reaches the storage chamber 41 of the reservoir 14 while being cooled. Here, since the fuel pressure downstream of the decomposer 28 is as high as about 30 atmospheres, propane, butane, etc. are condensed in the storage chamber 41 and stored as a fluid.

On the other hand, in the decomposer 28, methane, ethane, etc. are also decomposed and produced, but because of their high boiling points, they are not condensed.When the pressure reaches a predetermined level or higher, the relief valve is pushed open and the gas outlet 45 is passed through the intake passage. is supplied to the interior and subjected to combustion. When the low boiling point hydrocarbon fuel stored in the storage chamber 41 reaches a set amount, the solenoid valve 12 is closed by a command from the controller 20 in response to a detection signal from the level sensor 43, and the heating heater 28 is turned off. It is cut off and stops working, stopping the production of cracked gas.

On the other hand, when starting the engine, when the solenoid valve 15 is opened by a command from the controller 20 in response to a starting signal at the same time as cranking, the low boiling point hydrocarbon fuel stored in the storage chamber 41 is released from the solenoid valve 15°. Passage 46. The gas expands from the gas nozzle 17 through the gas outlet 45 and is ejected into the combustor 19, where it is ignited by the spark plug 18 and combusted. The combustion heat heats the intake air flowing through the intake passage to start the engine. In this case, propane.

Since low-boiling hydrocarbon fuels such as butane are easily vaporized, they are much easier to ignite than light oil and the like, and can be easily ignited even at temperatures as low as -20°C, allowing the engine to be started quickly.

When engine starting is completed and the rotation speed exceeds the set value (7), the solenoid valve 15 closes in response to a command from the controller 20 in response to the rotation speed signal, and the supply of low boiling point hydrocarbon fuel is stopped. As described above, the decomposer 13 is operated until the low boiling point hydrocarbon fuel in the reservoir 14 reaches a set amount.
The decomposition and production of fuel takes place in the process.

With such a configuration, as described above, the fuel for heating the intake air is a low boiling point hydrocarbon and is supplied in gaseous form, so that it can be ignited and burned at approximately the same time as engine cranking, and the engine can be started quickly. can.

As explained above, according to the present invention, low boiling point hydrocarbon fuel generated by decomposing fuel during engine operation is stored,
The stored fuel is gasified under reduced pressure when the engine is started, supplied into the intake passage, and ignited and combusted to heat the intake air, so even in extremely cold weather, the intake air can be heated in an extremely short period of time without preheating the fuel. The engine can be started.

In addition, since it does not affect the shape of the combustion chamber, combustion
8) Good fuel efficiency can be maintained without impairing performance.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is an overall configuration diagram showing an example of a conventional engine starting aid device, Fig. 2 is an overall configuration diagram showing an embodiment of the present invention, and Fig. 3 is a diagram showing an example of the same as the above embodiment. Cross-sectional view of the decomposer used, No. 4
The figure is a cross-sectional view of a reservoir used in the same embodiment. 11... Piping 12... Solenoid valve 13... Decomposer 14... Reservoir 15... Solenoid valve 16
...Intake manifold 18...Spark plug 19...Combustor 20...Controller 2
4...Ff [Patent applicant: Nissan Motor Co., Ltd. Patent attorney: Fujio Sasashima

Claims (1)

[Claims] A decomposer that decomposes hydrocarbon fuel in the presence of a catalyst to generate low-boiling hydrocarbon fuel during engine operation; a reservoir that stores the low-boiling hydrocarbon fuel; 1. A combustor for igniting and burning low boiling point hydrocarbon fuel supplied from the reservoir.