JPS5815643Y2 - Diesel engine auxiliary fuel supply system - Google Patents

Description

[Detailed description of the invention] This invention provides a low-cost, special supply device that allows air-fuel mixture to be sucked into the cylinder by adjusting the intake valve to suit the purpose of shortening the ignition delay time of a diesel engine. In general, in a diesel engine, fuel is injected into the swirl combustion chamber or directly into the cylinder during the compression process to ignite, but there is a so-called ignition delay time between injection and ignition. do.

When the ignition delay time becomes longer, the fuel burns rapidly, producing a knocking sound, and the amount of Nox in the exhaust gas also increases.

Therefore, in order to solve the draft caused by this ignition delay, it is known to supply auxiliary fuel into the cylinder separately from the main fuel.

In other words, if a part of the fuel is supplied into the cylinder as auxiliary fuel when air is taken in, the auxiliary fuel supplied when air is taken in will cause high heat inside the cylinder for quite a long time until the end of the compression stroke when the main fuel is injected. As a result, oxidation progresses, resulting in an activated state.

When the main fuel is subsequently injected, it becomes as if the cetane number has increased, the ignition delay is reduced, abnormal explosions do not occur, and the engine runs smoothly.

For this reason, various devices have been proposed for supplying a portion of the fuel into the cylinder during the intake process.

For example, there is a method in which a separate injection pump and injection nozzle are provided for supplementary fuel supply and fuel is injected into the intake pipe.

However, this method cannot create an optimal atmosphere in response to changes in engine operating conditions, and is mechanically complex and expensive.

Also, if an injection nozzle were installed at the intake port of each cylinder, it would be even more expensive, but if there was only one injection nozzle and the fuel was injected only to the gathering part of the intake pipe, the fuel would not stick to the intake pipe wall. The amount of combustion involved in combustion is reduced and the combustion becomes unstable, which not only worsens combustion but also makes operation unsmooth.

This proposal eliminates these shortcomings and provides a practical device. In particular, when a carburetor that operates in accordance with the intake flow is adopted for the supply of auxiliary fuel, it is of great importance to solve the unique problems that arise there. The aim is to open the tip of the auxiliary passage, which is placed parallel to the engine's intake passage, near the back of the intake valve, and to install a carburetor for auxiliary fuel supply in the auxiliary passage, thereby improving engine operation. It is characterized in that auxiliary fuel is reliably supplied into the cylinder according to the state.

A configuration example of the present invention will be described below with reference to the drawings.

In the figure, 1 is the cylinder, 2 is the cylinder head, 3 is the piston, 4 is the intake valve, 5 is the intake port, 6 is the swirl combustion chamber,
1 is an injection pump for the main combustion paulownia, 8 is an injection nozzle, 9 is a glow plug, and as part of the intake passage are an intake pipe 10, a venturi 11. There is an air cleaner 12.

The above is the same as a conventional diesel engine.

The carburetor 14 has intake passages 5, 10, and 11.

It is provided between an auxiliary passage 15 arranged in parallel to the carburetor air cleaner 13 for auxiliary fuel supply, and uses a positive amount of intake negative pressure to supply the fuel to the cylinder head part through the auxiliary passage 15. The air is guided through the air to the intake port 5, and its tip opening 16 is opened near the back of the intake valve 4 to reliably supply the air into the cylinder.

In this case, the auxiliary passage 15, carburetor 14, and air cleaner 13 are installed in parallel with the intake passages 5, 10, 11.12 in a separate system with a small cross-sectional area, so large pulsations that occur in the intake passage will not occur. Therefore, the required amount of auxiliary fuel can be reliably supplied without being affected by pulsation.

The amount of fuel may be controlled by, for example, providing a valve in the carburetor that is synchronized with the accelerator to control the amount of auxiliary fuel in accordance with changes in the operating state of the engine.

If it is desired to maintain the amount of fuel from the carburetor within a proportion of the total amount of fuel, it is sufficient to synchronize the rack or governor of the injection pump on the main fuel side with the valve of the carburetor.

As explained above, if this idea is adopted, auxiliary fuel is supplied by a carburetor that utilizes the airflow in the intake system due to the intake negative pressure that indicates the operating status of the engine, which is mechanically simpler and cheaper than the injection type. Become something.

In addition, since the auxiliary passage with the carburetor is separate from the intake passage, and has a sufficiently smaller cross-sectional area than the intake passage, it is installed in parallel with the intake passage, so that unstable fuel supply due to pulsation is prevented, and this prevents the engine from running. It also becomes easy to control the amount of auxiliary fuel based on changes in operating conditions.

In particular, it becomes easier to control the minute amount of auxiliary fuel.

The air-fuel mixture from the carburetor passes through the cylinder head through the auxiliary passage, where it is heated and sufficiently vaporized before being guided to the back of the intake valve, ensuring that the required amount is not reduced and is stably and reliably fed into the cylinder. It is possible to supply it.

By supplying the auxiliary spark in this manner, the ignition delay is reduced, and the engine operates smoothly, combustion noise and NOx are sufficiently reduced, and output can be increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the device according to the present invention, and FIG. 2 is a plan view thereof. 4... Intake valve, 5t10tlL12...
... Intake passage, 13... Carburetor for auxiliary fuel supply 15... Auxiliary passage.

Claims (1)

[Scope of utility model registration request] An air cleaner is provided separately for the intake passage, and an auxiliary passage whose cross-sectional area is sufficiently smaller than that of the intake passage is arranged in parallel, and after passing through the cylinder head, the tip opening is opened near the back of the intake valve C. In addition, a carburetor for supplying auxiliary fuel is installed in the auxiliary passage.
An auxiliary fuel supply device for a diesel engine, characterized by: