JPS6014905Y2 - Internal combustion engine starting accelerator - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a starting promotion device for an internal combustion engine.

In order to start an internal combustion engine, especially a compression ignition engine, the temperature of the air after being compressed by its piston must be raised above the fuel ignition temperature.

Since the post-compression temperature is greatly influenced by the pre-compression (initial) temperature, increasing this temperature will improve starting performance.

For this reason, various measures have been taken to increase the pre-compression temperature, one of which is mounting 36-1260.
There is a known combustion engine as disclosed in Japanese Patent No. 7 in which the temperature of the air is increased by throttling the air flowing into the combustion chamber using a throttle valve.

To explain this, for example, after reducing the pressure inside container a below atmospheric pressure (vacuum) as shown in Figure 1, when the lid is opened and the pressure inside container a is restored to atmospheric pressure, the inflowing air will Adiabatic compression work is performed to increase the temperature inside container a.

The above is an application of this principle, and when the intake air is throttled by the throttle valve, the area from the throttle valve to the combustion chamber is under atmospheric pressure due to the downward movement of the piston during the intake stroke.

This pressure is supplemented by the atmosphere and restored to atmospheric pressure when the piston stagnates during the transition from the suction stroke to the compression stroke.

That is, at this time, adiabatic compression work is performed to increase the temperature within the combustion chamber.

However, in an engine having a large number of cylinders, several cylinders may be in the suction stroke at the same time.

In such an engine, if one intake manifold supplies intake air to each cylinder, even if one cylinder has decreased pressure and attempts are made to restore it,
When the piston of another cylinder is in the descending state during the intake stroke, the intake air in the combustion chamber of the previous cylinder is sucked out by the descent of the piston of this cylinder, since the intake manifold communicates with both cylinders. This will result in a situation where the pressure will not be recovered, that is, no adiabatic compression work will be done.

For this reason, in the conventional engine as described above, a throttle valve is provided at the inlet of each cylinder to prevent the cylinder from being influenced by other cylinders and to increase the adiabatic compression work.

However, providing a throttle valve for each cylinder not only increases the number of parts, but also restricts the throttle amount to a certain value to achieve the best effect. In order to increase the quantity, the product had to be manufactured with great care, which greatly increased the cost of the product.

The present invention aims to ensure efficient starting performance by using one intake throttle valve in a multi-cylinder engine, and will be explained below with reference to an embodiment shown in the drawings.

In FIGS. 2 to 4, numeral 1 denotes a cylinder formed in a cylinder body C of a four-stroke internal combustion engine E, into which a piston 2 is slidably inserted.

3 is a combustion chamber, 4 and 5 are intake valves and exhaust valves mounted on the cylinder head H, and 6 is a cam interlocked with a crankshaft (not shown).

The intake valve 4 and the exhaust valve 5 are operated by a tappet 7 lifted by a cam 6, a rod 8, and intake and exhaust rocker arms 9 and 10 swung by these to open and close an intake passage 11 and an exhaust passage 12.

In particular, the cam 6 that operates the exhaust valve 5 has a cam nose 6a that operates the valve opening 5 during the exhaust stroke, and a cam nose 6a that operates the exhaust valve 5 at the end of the intake stroke, for example, 500 minutes before the bottom dead center BDC, as shown by the solid line in FIG.
The cam nose 6b is opened from 700 at the beginning of the compression stroke, for example, after bottom dead center BDC.

Reference numeral 13 denotes an intake manifold, and the intake manifold 13 has an intake throttle valve 1 at an inlet part 13b where branch pipes 13a leading to each cylinder are assembled.
There are 4.

15 is a controller that operates the intake throttle valve 14, and shows an example in which the intake throttle valve 14 is operated electromagnetically.

16 is a starting switch, and 17 is a power source. When the starting switch 16 is closed (turned ON), the controller 15 rotates the intake throttle valve 14 to throttle the intake pipe passage 13c, and at the same time, a starter ST (not shown) rotates the crankshaft. let

At this time, the gap between the intake manifold 13 and the intake throttle valve 14 is such that the negative pressure in the intake passage 13c on the piston 2 side downstream of the valve opening 14 is zero.
．． The pressure is adjusted to 1 to 0.5 atm.

Note that 18 is an exhaust manifold that communicates with the exhaust path 12.

Now, when you turn on the starting switch 16 to start the engine, the controller 15 rotates the intake throttle valve 14 to open the intake pipe passage 1.
At the same time as tightening 3c, the starter ST operates each part via the crankshaft.

In this state, when the intake valve 4 opens and the piston 2 begins to descend, intake air begins to flow into the combustion chamber 3.

However, since the air flowing into the combustion chamber 3 is throttled by the intake throttle valve 14, it can flow in sufficiently, so that the internal pressure of the combustion chamber 3 becomes lower than atmospheric pressure.

On the other hand, the inside of the exhaust passage 12 is at atmospheric pressure because the exhaust manifold 13 communicates with the atmosphere. When opened, air flows into the combustion chamber 3 from the exhaust passage 12 due to the pressure difference with the inside of the combustion chamber 3, and the pressure inside the chamber 3 is restored.

That is, at this time, adiabatic compression work is performed to increase the air temperature within the combustion chamber 3.

As described above, the present invention provides an intake throttle valve provided at the intake manifold joint of a four-stroke internal combustion engine, a control device that operates the throttle valve to throttle intake air when the engine is started, and an exhaust valve of the engine. In addition to the exhaust stroke, the engine has an exhaust valve mechanism that can open between the end of the intake stroke and the beginning of the compression stroke. On the other hand, the exhaust valve is opened for each cylinder from the intake stroke to the compression stroke, and fresh air is injected for adiabatic compression. It is possible to increase the adiabatic compression work, that is, the air temperature in the combustion chamber 3, with a simpler structure compared to the above.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining adiabatic compression work, Figs. 2 to 4 are an embodiment of the present invention, and Fig. 2 is a front view.
FIG. 3 is a sectional view of FIG. 2, FIG. 4 is an enlarged view of the main part, and FIG. 5 is an explanatory diagram showing a valve lift curve. 1: Cylinder, 2: Piston, 3: Combustion chamber, 4: Intake valve, 5: Exhaust valve, 6: Cam, 13: Intake polytracheal pipe, 14: Intake throttle valve.

Claims (1)

[Scope of utility model registration request] An intake throttle valve installed at the intake manifold of a four-cycle internal combustion engine, a control device that operates the throttle valve to throttle the intake air when the engine is started, and an exhaust valve of the engine that operates during the intake stroke as well as the exhaust stroke. It has an engine exhaust valve mechanism that can open between the end of the compression stroke and the beginning of the compression stroke. From the stroke to the compression stroke, the exhaust valve is opened,
A starting accelerator for an internal combustion engine characterized by injecting fresh air and adiabatically compressing it.