JPH0534512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an alcohol engine, and more particularly to an alcohol engine that extracts output by injecting and burning alcohol fuel into a cylinder.

〓Summary of the Invention〓 The present invention uses a forced ignition means such as a spark assist plug and a self-ignition accelerator together in an alcohol engine, and ignites the alcohol by means of the forced ignition means depending on the state of the engine. A self-ignition accelerator is added to the alcohol fuel depending on the engine condition, so that stable combustion can always be obtained regardless of the engine condition.

<Prior Art> An alcohol engine has been proposed in which alcohol is used instead of light oil as fuel for a diesel engine. Alcohol engines do not contain nitrogen oxides or carbon monoxide in their exhaust gas, and have the property of being difficult to emit harmful substances. For these reasons, alcohol engines are attracting attention as clean engines.

〓Problems to be solved by the invention〓 However, alcohol fuel has a problem in that it has inferior self-ignition properties compared to light oil. In order to overcome these drawbacks, it has been proposed to add an autoignition accelerator to the fuel. However, self-ignition accelerators are very expensive, so if such agents are constantly mixed with fuel and combusted, fuel costs will increase, and when used in vehicle engines, running costs will increase. It has the disadvantage of being expensive.

The present invention has been made in view of these problems, and it improves ignitability by adding a self-ignition accelerator to alcohol fuel, and also reduces its use to the necessary minimum. ,
The object of the present invention is to provide an alcohol engine that reduces running costs.

<Means for Solving the Problems> The present invention provides an engine in which output is obtained by injecting alcohol fuel into a cylinder and combusting it. A means for adding a self-ignition promoter to the alcohol fuel is provided, and ignition is performed by the forced ignition means depending on the engine condition, and the self-ignition promoter is added to the alcohol fuel depending on the engine condition. be.

〓Operation〓 Therefore, according to the present invention, it is possible to perform ignition by the forced ignition means and addition of the self-ignition accelerator depending on the state of the engine, thereby reducing the usage amount of the self-ignition accelerator. This makes it possible to reduce fuel costs and running costs.

Embodiment FIG. 2 shows a diesel-type alcohol engine 10 according to an embodiment of the present invention, and an intake manifold 11 and an exhaust manifold 12 are installed on both sides of the engine 10. . The intake manifold 11 is the intake pipe 1
3, and an air cleaner 14 is connected to the tip side of this intake pipe 13. On the other hand, the exhaust manifold 12 is connected to an exhaust pipe 15, and an oxidation catalyst 16 filled in a cylindrical case is attached to the exhaust pipe 15.

On the downstream side of the catalyst 16, the exhaust pipe 15 communicates with the intake pipe 13 through a communication pipe 19, and an EGR valve 20 is connected to the communication pipe 19.
is connected. Therefore, by opening this valve 20, it becomes possible to return the exhaust gas to the intake side. and a controller 2 consisting of a microcomputer to control the EGR valve 20.
1 is provided. This controller 21 is
A spark assist plug 22 provided in each cylinder of the engine 10 is controlled. Further, on the input side of the microcomputer 21, as shown in FIG. 1, a rotation detection sensor 23, a load sensor 24, a rack position sensor 27 (see FIG. 2) provided on the electronic governor 26 of the fuel injection pump 25, and an intake air temperature sensor 28 attached to the intake manifold 11.

Next, to explain the fuel supply system of this engine, a fuel injection pump 25 is attached to the side of the engine 10 as shown in FIG. 1, and a timer 32 is attached to the camshaft 31 of this pump 25. A timer 32 is used to adjust the timing of fuel injection. Further, a feed pump 33 is attached to the side surface of the fuel injection pump 25, and the feed pump 33 is connected to a fuel tank 34 via a fuel supply pipe 35. Further, a filter 36 is connected between the feed pump 33 and the fuel injection pump 25. Further, a return pipe 37 is connected to the fuel injection pump 25 to return excess fuel to the fuel tank 34. The discharge side of each pump unit of the fuel injection pump 25 is connected via an injection pipe 38 to a fuel injection nozzle 39 provided in a cylinder of the engine 10.

Next, a device for adding a self-ignition accelerator to alcohol fuel will be explained. The filter 36 of the fuel supply pipe 35 and the fuel injection pump 2
A bench lily 42 is connected to the portion 5, and a self-ignition accelerator supply pipe 43 is connected to this bench lily 42. A solenoid valve 44, a filter 47, and a feed pump 45 are connected to this pipe 43. These solenoid valves 4
4 and the feed pump 45 are both controlled by the microcomputer 21. Further, the end of the pipe 43 is connected to an accelerator tank 46.
The accelerator in this tank is sucked out.

In the above configuration, when the fuel injection pump 25 is driven by a portion of the output of the engine 10 through the camshaft 31, the methanol fuel sucked from the fuel tank 34 by the feed pump 33 is transferred to the fuel injection pump 25. The fuel is thus pressurized and sequentially supplied to the fuel injection nozzle 39 through the injection pipe 38. The injection timing at this time is controlled by a timer 32, and the amount of fuel injected at one time is controlled by an electronic governor 26. The alcohol fuel spray injected into the cylinder is ignited as necessary by a spark assist plug 22 shown in FIG.

Further, in this alcohol engine 10, a self-ignition accelerator is added to the alcohol fuel as necessary. The accelerator is added when the condition of the engine 10 falls within the shaded area in the graph shown in FIG. That is, as shown in FIG. 4, the microcomputer 21 reads the number of rotations of the engine using the rotation detection sensor 23, and also reads the load of the engine using the load sensor 24. When it is determined that the area is where the accelerator should be introduced, the state of the solenoid valve 44 is detected, and if the solenoid valve 44 is closed, it is opened and the self-ignition is carried out through the feed pump 45. An accelerator is supplied to the bench lily 42.
Therefore, alcohol fuel and accelerator are mixed by this bench lily 42. Note that if the solenoid valve 44 is open, it remains open. Further, when it is determined that the area is not the area where the accelerator should be introduced, the state of the electromagnetic valve 44 is detected, and if the electromagnetic valve 44 is open, it is closed. Further, if it is not opened, it is maintained as it is.

Further, this alcohol engine 10 is configured to perform EGR, and when the intake air temperature is low or when the engine 10 is started, the microcomputer 21 detects this and opens the EGR valve 20. As a result, part of the exhaust gas is returned to the intake pipe 13 side through the communication pipe 19, and the temperature of the intake air increases. Therefore, the temperature inside the cylinder also rises, making it possible to prevent ignition errors. Further, harmful substances such as unburned components of alcohol fuel and formaldehyde contained in the exhaust gas are oxidized into carbon dioxide gas and water by an oxidation catalyst 16 connected to the exhaust pipe 15. This prevents harmful substances from being contained in the exhaust gas.

In this way, the engine 10 of this embodiment is designed to use the assist plug 22 and the self-ignition accelerator supply means in combination. In this engine 10, 100% methanol fuel is used, and the compression ratio is set to a high compression ratio of about 27.
It is intended to be combined with the EGR valve 20. This allows operation with 100% methanol. Moreover, in the area shown by diagonal lines in Figure 3, such as during startup and at low speed and high load,
In areas where exhaust gas recirculation by the EGR valve 20 cannot be used, a self-ignition accelerator is used.

As the self-ignition accelerator, it is possible to use, for example, nitrite ester (accelerator AVOCET (trademark) manufactured by Imperial Chemical Industries Ltd., UK). Such agents are relatively expensive and their constant use creates fuel cost problems. Therefore, fuel costs are reduced by using such chemicals only within the necessary range as described above. This also makes it possible to simplify the countermeasures on the engine side, resulting in lower engine costs.

〓Effects of the Invention〓 As described above, according to the present invention, ignition is performed by a forced ignition means according to the condition of the engine, and a self-ignition accelerator is further added to the alcohol fuel according to the condition of the engine. It is. Therefore, there is no need to constantly add an expensive self-ignition accelerator to the alcohol fuel, which reduces the amount of accelerator used, making it possible to lower fuel costs and lowering running costs. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the fuel supply system of an alcohol engine according to an embodiment of the present invention, FIG. 2 is a block diagram showing the intake and exhaust system of the same engine, and FIG.
The figure is a graph showing the range in which the self-ignition accelerator is added, and FIG. 4 is a flowchart showing the operation of adding the auto-ignition accelerator. In the symbols used in the drawings, 10... Alcohol engine, 16... Oxidation catalyst, 20... EGR valve, 21... Controller (microcomputer), 22... Spark assist plug, 25... Fuel injection pump, 26... Electronic governor, 32... Timer, 33... Feed pump, 39... Fuel injection nozzle, 42... Bench lily, 44... Solenoid valve, 45... Feed pump, 46... Accelerator tank.

Claims (1)

[Claims] 1. In an engine that extracts output by injecting and burning alcohol fuel into a cylinder, a forced ignition means is provided in the cylinder, and a means for adding a self-ignition accelerator to the alcohol fuel is provided, and the engine An alcohol engine characterized in that ignition is carried out by the forced ignition means depending on the state of the fuel, and a self-ignition accelerator is added to the alcohol fuel depending on the state of the engine.