JP2013127212A - Diesel engine rotation stability detecting device, diesel engine, and diesel engine rotation stability detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine rotation stability detecting device enabling a diesel engine to operate for a long period using mixed oil of petroleum fuel oil and unrefined waste oil not subjected to reformation such as esterification.SOLUTION: The diesel engine rotation stability detecting device has a pulse width measuring means measuring the pulse width of rotation pulse signals output from a rotation angle sensor, a rotation pulse counting means counting the rotation pulse signals output from the rotation angle sensor in series and zeroing the counted value when a detecting reference part is detected, and a cylinder specifying means specifying in which cylinder of the plurality of cylinders combustion abnormality is generated based on the counted value when the pulse width measuring means detects the abnormality of the pulse width.

Description

  TECHNICAL FIELD The present invention relates to a diesel engine rotational stability detection device that mixes petroleum-based fuel oil such as light oil and heavy oil with waste oil such as non-refined animal and vegetable waste cooking oil and mineral oil, and uses the mixed oil as fuel. .

In recent years, research and development to reuse animal and vegetable waste edible oils such as edible fats and oils and engine oils that have been discharged from the food industry and general households and processed as waste as raw materials for diesel engine fuels have become a resource. It has been promoted from the viewpoint of protection and environmental protection.
In the present specification, the generic name of the used waste cooking oil and mineral oil is referred to as “waste oil”.

For example, Patent Document 1 discloses a technique of using fatty acid methyl ester obtained by refining waste cooking oil and methyl alcohol by a transesterification reaction under specific conditions as a biodiesel fuel.
Biodiesel fuel obtained by refining such waste cooking oil is carbon neutral, and thus has attracted attention as a fuel with low environmental impact.

However, there is a problem that a separate facility for esterifying waste cooking oil is required, and the cost of fuel is increased because the construction cost and esterification cost of the facility are transferred to the price. .
Moreover, the spread of biodiesel fuel has been delayed due to high fuel prices.

Therefore, a technique is also known in which waste cooking oil is mixed with petroleum-based fuel oil without being reformed, and this mixed oil is used as fuel for a diesel engine.
Since waste cooking oil generally has a high viscosity, for example, when a diesel engine is started under a low temperature condition, the fuel supply path may not flow smoothly, and fuel supply may become unstable. Therefore, a technique is known in which waste cooking oil is adjusted to an appropriate viscosity by heating in a fuel supply path. However, since waste cooking oil is easily oxidized and deteriorated by heating, there is a risk of adverse effects such as deterioration of fuel consumption.
Therefore, Patent Document 2 discloses that a fuel oil is a mixture of a low-viscosity petroleum-based fuel oil and a high-viscosity non-refined waste edible oil, and satisfies a preset viscosity condition and has a high viscosity and non-refined waste edible oil A technique is disclosed in which the mixing ratio is corrected without heating the fuel oil so that the content of is maximized. According to this, high-viscosity non-refined waste cooking oil, which is advantageous in terms of price and carbon dioxide emission compared to petroleum-based fuel oil, can be used to the maximum.

Japanese Patent Laid-Open No. 07-197047 JP 2009-121367 A

However, the technique disclosed in Patent Document 2 has the following problems.
That is, the technique disclosed in Patent Document 2 pays attention to the viscosity of the mixed oil. The viscosity condition of the mixed oil suitable for supply to the diesel engine is set in advance, and the mixing is performed to satisfy the viscosity condition. The mixture ratio is corrected while referring to a fuel map showing the correspondence between the ratio, the viscosity, and the temperature.
Therefore, it is difficult to cope with the case where the viscosity conditions set in advance are not appropriate, the environmental changes (temperature, humidity and pressure changes) during diesel engine operation, and the quality changes and variations of waste cooking oil. There was a problem of being.

Moreover, various impurities are contained in non-refined waste cooking oil, and even if it is the waste cooking oil obtained from the same raw material, the correspondence of the viscosity and temperature is not uniform.
Therefore, in order to accurately correct the fuel oil mixing ratio during operation of the diesel engine, it is necessary to create a fuel map for each waste cooking oil scheduled to be used. In other words, if one type of fuel map is used for one type of waste cooking oil feedstock, the mixture ratio cannot be corrected accurately, and it is difficult to operate the diesel engine stably over a long period of time. There was a problem.
As described above, various technologies for realizing stable operation over a long period of time have been researched and developed for diesel engines using a mixture of petroleum-based fuel oil and non-refined waste oil. The current situation has not yet been established.

  In view of such problems, the present invention detects an unstable operating state in a diesel engine that uses a mixed oil of petroleum fuel oil and non-refined waste oil that is not reformed, such as esterification. An object of the present invention is to provide an engine rotation stability detection device, a diesel engine, and an engine rotation stability detection method that enable a diesel engine to be stably operated for a long period of time by performing appropriate measures.

  The diesel engine rotational stability detecting device of the present invention is a diesel engine rotational stability detecting device that uses a mixed oil obtained by mixing petroleum-based fuel oil and non-refined waste oil as fuel, and is synchronized with the rotation of the engine. And a rotation pulse signal generating tooth and a detection reference portion located at a position corresponding to the crank angle detection reference position on the flywheel that is rotationally driven. A rotation angle sensor that detects the presence and outputs a rotation pulse signal of the flywheel, a pulse width measurement unit that measures a pulse width of the rotation pulse signal output from the rotation angle sensor, and an output from the rotation angle sensor The rotation pulse signal is sequentially counted, and when the detection reference part is detected, the rotation pulse counting means for setting the count value to zero, and the pulse width When the measuring means detects an abnormality of the pulse width, characterized in that it comprises a cylinder specifying means for specifying the abnormality combustion has occurred in which cylinder of the plurality of cylinders based on the counted value.

  Moreover, the diesel engine of this invention is equipped with the rotation stability detection apparatus of the said diesel engine, It is characterized by the above-mentioned.

  The method for detecting the rotational stability of a diesel engine according to the present invention is a method for detecting the rotational stability of a diesel engine using a mixed oil obtained by mixing petroleum-based fuel oil and non-refined waste oil as a fuel. Detects the presence of a detection reference portion that exists at a position corresponding to the detection reference position of the rotation pulse signal generation tooth and the crank angle of the flywheel that is driven to rotate in synchronization with the rotation of the engine. A step of outputting a pulse signal; a step of measuring a pulse width of the rotation pulse signal output from the rotation angle sensor; and a step of counting a rotation pulse of the rotation angle sensor. The step of sequentially counting the rotation pulse signal and detecting the detection reference portion to make the count value zero, and the cylinder specifying means, When serial pulse width measurement means detects an abnormality of the pulse width, characterized in that it comprises a step of identifying whether abnormal combustion in which cylinder of the plurality of cylinders has occurred based on the counted value.

  According to the present invention, when the pulse width measuring unit detects an abnormality in the pulse width, the cylinder specifying unit determines which cylinder among the plurality of cylinders has the combustion abnormality based on the count value by the rotation pulse counting unit. Because it can be identified, abnormal combustion conditions can be detected early and easily, and by appropriately responding to abnormalities, a diesel engine that uses a mixture of petroleum-based fuel oil and non-refined waste oil can be operated stably over a long period of time. It becomes possible to do.

The figure which shows the structure of the rotational stability detection apparatus of a diesel engine Block diagram showing the configuration of a diesel engine rotational stability detector Schematic showing the flywheel and rotation angle sensor A diagram (a) showing the pulse width of the rotation pulse signal in a state where the engine is stably rotating, and a diagram (b) showing the pulse width of the rotation pulse signal in a state where combustion abnormality has occurred in the cylinder. It is a flowchart which shows the rotational stability detection method of a diesel engine. It is a figure which shows the structure at the time of applying the rotational stability detection apparatus of the diesel engine of this invention to the diesel engine for vehicles.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the rotational stability detecting device 10 for a diesel engine shown in the present embodiment includes petroleum-based fuel oil such as light oil and non-refined waste that has not been reformed by esterification. Waste oil such as edible oil is mixed and applied to the diesel engine 20 using this mixed oil as fuel.
In the present embodiment, an example in which a rotational stability detection device is applied to a diesel engine used as a drive source for a generator will be described.

First, the configuration of the diesel engine 20 will be described, but detailed description of portions that are the same as the configuration of a diesel engine that is generally widely known will be omitted.
The diesel engine 20 includes an engine main body 30 that extracts rotational energy by burning a mixed oil of petroleum-based fuel oil and non-refined waste oil, fuel supply means 40 that supplies the mixed oil to the engine main body 30 as supplementary notes, An air supply means 50 for supplying air to the engine body 30 and an exhaust manifold 60 are configured.
It is possible to supply not only the above-mentioned mixed oil but also petroleum-based fuel oil from the fuel supply means 40 to the engine main body 30 according to the driving condition of the engine. explain.

The fuel supply means 40 supplies the mixed oil from the fuel mixing tank 13a to a fuel injection valve (not shown) of the engine body 30.
The fuel supply means 40 includes a fuel supply pump 41, an injection amount control device (a governor) 42, and an actuator 43.
The injection amount control device 42 is driven by an actuator 43 controlled by an ECU (Electronic Control Unit) 80, which will be described later, and is a cylinder (not shown) from the fuel supply pump 41 via a fuel injection valve. The amount of fuel injected into the inside is adjusted.

  The air supply means 50 includes an air cleaner 51, a supercharger 52, etc., and after removing dust in the air by the air cleaner 51, each cylinder of the engine body 30 is set to a pressure higher than the external pressure by the supercharger 52. To supply. Exhaust gas after combustion in each cylinder is released into the atmosphere via the exhaust manifold 60 and a muffler (not shown). Note that the supercharger 52 may not be provided.

A rotary shaft 23 of a three-phase AC generator 22 is connected to one end of the rotary shaft 21 of the diesel engine 20 via a joint 24. The engine body 30 is provided with a rotation speed detector 25 that detects the rotation speed of the diesel engine 20.
As shown in FIGS. 1 and 3, the rotation speed detector 25 includes a flywheel 25 a provided at one end of the rotation shaft 26, and a rotation angle sensor 25 b disposed close to the flywheel 25 a. .

The flywheel 25a is rotationally driven in synchronism with the rotation of the diesel engine 20, and has convex teeth 25c provided at a constant pitch on the outer peripheral edge thereof, and a position corresponding to the crank angle detection reference position. A detection reference portion 25d is provided.
The rotation angle sensor 25b detects the tooth 25c of the rotating flywheel 25a and generates a pulse signal (see FIG. 4A) corresponding to the width of the tooth 25c. This pulse signal is transmitted to a pulse width measuring means 81 and a rotation pulse counting means 82 in an ECU 80 (Electronic Control Unit) described later. The rotation angle sensor 25 b detects the detection reference portion 25 d and transmits a detection signal to the rotation pulse counting means 82.

  The diesel engine 20 includes a first fuel tank 11 for storing waste oil as supplementary notes, a second fuel tank 12 for storing petroleum-based fuel oil, a fuel mixture connected to the first fuel tank 11 and the second fuel tank 12. Means 13, waste oil amount adjusting means 14, petroleum-based fuel oil amount adjusting means 15, fuel switching valve 16, ECU 80, and fuel return switching valve 17 are provided.

  A filter 11c is connected to the waste oil outlet 11a of the first fuel tank 11 via a waste oil outflow pipe 11b. The filter 11c collects a generated substance and other impurities (dust) generated by oxidative degradation of the waste oil floating in the waste oil, and includes a filter medium. By providing this filter 11c, waste oil collected from restaurants, households, etc., that is, non-refined waste oil that has not been subjected to reforming treatment such as esterification, is directly put into the first fuel tank 11 to fuel the diesel engine 20 It becomes possible to use as.

The fuel mixing means 13 mixes the waste oil supplied from the first fuel tank 11 and the petroleum fuel oil supplied from the second fuel tank 12. The fuel mixing tank 13 a, the waste oil and the petroleum fuel A stirrer 13b that stirs and mixes oil and a liquid level gauge 13c that detects the liquid level of the mixed oil MO in the fuel mixing tank 13a at two points, an upper limit level and a lower limit level.
The signals of the upper limit level and the lower limit level detected by the liquid level gauge 13c are taken into the ECU 80 and are used for control of the waste oil amount adjusting means 14, the petroleum-based fuel oil amount adjusting means 15 and the stirrer 13b.

The waste oil amount adjusting means 14 includes a pipe 14a for connecting the filter 11c and the fuel mixing tank 13a in communication, open / close valves 14b and 14c provided on the upstream end side and the downstream end side of the pipe 14a, a filter The electromagnetic pump 14d which supplies the waste oil which permeate | transmitted 11c to the fuel mixing tank 13a, and the flow control valve 14e which controls the waste oil flow volume from the electromagnetic pump 14d are comprised. The electromagnetic pump 14d and the flow rate control valve 14e are controlled by the ECU 80.
The petroleum-based fuel oil amount adjusting means 15 includes a pipe 15a that connects the second fuel tank 12 and the fuel mixing tank 13a in a communicating state, and open / close valves provided on the upstream end side and the downstream end side of the pipe 15a, respectively. 15b, 15c, an electromagnetic pump 15d for supplying petroleum fuel oil from the second fuel tank 12 to the fuel mixing tank 13a, and a flow control valve 15e for controlling the flow rate of petroleum fuel oil from the electromagnetic pump 15d. It is configured to include. The electromagnetic pump 15d and the flow rate control valve 15e are controlled by the ECU 80.

The mixed oil supply pipe 13d connected to the fuel mixing tank 13a, the petroleum-based fuel oil supply pipe 15f connected to the second fuel tank 12, and the fuel supply pipe 41a connected to the fuel supply pump 41 are connected via the fuel switching valve 16. Connected.
The fuel switching valve 16 is provided to switch the pipe connected to the fuel supply pipe 41a to one of the mixed oil supply pipe 13d and the petroleum-based fuel oil supply pipe 15f, and is based on a command signal output from the ECU 80. Works.
An opening / closing valve 14f is provided upstream of the mixed oil supply pipe 13d, and an opening / closing valve 15g is provided upstream of the petroleum-based fuel oil supply pipe 15f.

A mixed oil return pipe 13e connected to the fuel mixing tank 13a, a petroleum-based fuel oil return pipe 15h connected to the second fuel tank 12, and a fuel return pipe 41b connected to the fuel supply pump 41 are provided with a fuel return switching valve 17. Connected through.
The fuel return switching valve 17 is provided to switch the pipe connected to the fuel return pipe 41b to one of the mixed oil return pipe 13e and the petroleum-based fuel return pipe 15h, and generates a command signal output from the ECU 80. Work on the basis.

An opening / closing valve 13f is provided upstream of the mixed oil return pipe 13e, and an opening / closing valve 15i is provided upstream of the petroleum-based fuel oil return pipe 15h.
A surplus portion of the waste oil supplied from the fuel supply pump 41 to the fuel injection nozzle is returned to the fuel mixing tank 13a through the mixed oil return pipe 13e by the operation of the fuel return switching valve 17. In addition, when only the petroleum fuel oil is supplied from the fuel supply pump 41 to the fuel injection nozzle, the surplus portion of the petroleum fuel oil passes through the petroleum fuel return pipe 15 h by the operation of the fuel return switching valve 17. Through the second fuel tank 12.

Next, the configuration of the diesel engine rotational stability detection device 10 will be described.
As shown in FIG. 2, the rotational stability detecting device 10 for a diesel engine includes a pulse width measuring means 81, a rotational pulse counting means 82, a cylinder specifying means 83, and the above-described flywheel 25a and rotational angle sensor 25b. The pulse width measuring means 81, the rotation pulse counting means 82, and the cylinder specifying means 83 are stored in an ECU 80 that manages and controls the driving of the diesel engine 20 and auxiliary machinery.

The pulse width measuring means 81 measures the pulse width of the rotation pulse signal output from the rotation angle sensor 25b.
In a state where the operation of the diesel engine 20 is stable, that is, in a state where the compression / self-ignition / combustion / exhaust cycle is regularly performed in each cylinder, the fly immediately after combustion (explosion) occurs in the first cylinder. The rotational speed (angular speed) of the wheel 25a increases, the rotational speed of the flywheel 25a decreases until the next second cylinder burns, and the rotational speed increases again immediately after the second cylinder burns. Repeatedly, when the combustion of all the cylinders is completed, the detection reference portion 25d of the flywheel 25a returns to the position facing the rotation angle sensor 25b.

Since the increase / decrease in the rotational speed of the flywheel 25a appears in the length (width) of the pulse signal, the pulse width of the rotational pulse signal is also shown in FIG. 4 (a) when the diesel engine 20 is rotating stably. the first cylinder is P ₁ at -1 shortened immediately after combustion to, then P ₁ -2 will gradually increase up to P ₁ -6 from, it becomes again shortened immediately after the second cylinder is burnt (P is repeated regularly that ₂ -1).
Therefore, the pulse width measuring unit 81 continues to measure the pulse width of the rotation pulse signal, and outputs an abnormal signal to the cylinder specifying unit 83 when an abnormality occurs in the pulse width.
And if the abnormal pulse width occurs, for example, as shown in FIG. 4 (b), and if the up pulse width P ₂ -1~P _{2 -6} second cylinder is almost the same, FIG. 4 This refers to the case where the pulse width is remarkably longer or shorter than the stable state of (a).

The rotation pulse counting means 82 sequentially counts the rotation pulse signal output from the rotation angle sensor 25b, transmits it to the cylinder specifying means 83, and receives the detection signal output from the rotation angle sensor 25b. Is transmitted to the cylinder specifying means 83.
When the cylinder specifying unit 83 receives the abnormal signal transmitted from the pulse width measuring unit 81, which cylinder among the plurality of cylinders has a combustion abnormality based on the count value received from the rotation pulse counting unit 82 Is specified.

  Specifically, for example, when the pulse width is longer than that in the stable state, the rotational speed of the flywheel 25a is decreased, and the moving speed of the tooth 25c passing immediately before the rotational angle sensor 25b is decreased. Means. Therefore, when the pulse width is disturbed, it is based on the count value that the tooth 25c that has generated the pulse causing the disorder is the tooth 25c formed from the detection reference portion. Thus, the tooth 25c is identified, thereby identifying which cylinder among the plurality of cylinders has the combustion abnormality.

In addition to the pulse width measuring unit 81, the rotation pulse counting unit 82, and the cylinder specifying unit 83, the ECU 80 includes a CPU, a ROM that stores a control program and various data, a RAM that provides a working area, An interface unit with peripheral circuits and the like are stored, and these are connected by a bus. When the CPU executes the control program, the pulse width measuring means 81, the rotation pulse counting means 82, the cylinder specifying means 83, etc. are realized.
When the cylinder in which the combustion abnormality has occurred is specified by the cylinder specifying means 83, for example, the pipe connecting the fuel switching valve 16 to the fuel supply pipe 41a is connected to the petroleum-based fuel oil according to a command signal output from the ECU 80. By switching to the supply pipe 15f, the diesel engine 20 is driven only by petroleum fuel oil, the mixing ratio of waste oil and petroleum fuel oil is adjusted by the flow control valves 14e and 15e, or the diesel engine 20 is driven. Processing such as stopping is performed.
In the present embodiment, the diesel engine 20 includes three or more cylinders in FIG. 3 and the like, but the present invention is not limited to this, and the number of cylinders may be two or more.

Next, a rotation stability detection method using the diesel engine rotation stability detection device 10 according to the present embodiment will be described with reference to FIG.
First, the mixing ratio of the waste oil in the fuel when the operator starts the diesel engine 20 is suppressed to zero or low (for example, 5%).

The pulse width measuring means 81 measures the pulse width of the rotation pulse signal output from the rotation angle sensor 25b, and determines whether or not an abnormality has occurred in the pulse width (step 1).
If “YES” in step 1, that is, if an abnormality occurs in the pulse width, the process proceeds to step 2.
In step 2, the cylinder specifying means 83 determines whether or not an abnormal signal has been received from the pulse width measuring means 81, and when received (YES), a combustion abnormality has occurred based on the rotational pulse count value. A series of processing operations are completed by specifying the cylinder.

In the above embodiment, the example in which the rotational stability detecting device for a diesel engine of the present invention is applied to a diesel engine used as a drive source of a generator has been shown. However, the present invention is not limited to this, and a diesel engine for a vehicle is used. It can also be applied to.
FIG. 6 shows a configuration when applied to a diesel engine for a vehicle. The basic configuration is the same as that shown in each of the above embodiments, except that the output of the diesel engine 20 is transmitted not to the three-phase AC generator 22 but to the vehicle drive mechanism 90 including a drive shaft, drive wheels, etc. The difference is that an actuator 43 for driving the quantity control device 42 is not provided. The injection amount control device 42 is controlled by the operator adjusting the amount of depression of an accelerator pedal (not shown).

  This is related to an engine rotation stability detection device that makes it possible to operate a diesel engine stably for a long period of time using a mixed oil of petroleum-based fuel oil and non-refined waste oil. Have.

DESCRIPTION OF SYMBOLS 10 Diesel engine rotational stability detection apparatus 11 1st fuel tank 12 2nd fuel tank 13a Fuel mixing tank 14 Waste oil amount adjustment means 15 Petroleum-type fuel oil amount adjustment means 20 Diesel engine 25 Revolution detector 25a Flywheel 25b Rotation angle sensor 30 Engine body 40 Fuel supply means 50 Air supply means 60 Exhaust manifold 80 ECU
81 Pulse width measuring means 82 Rotation pulse counting means 83 Cylinder specifying means 90 Vehicle drive mechanism

Claims (3)

A rotational stability detecting device for a diesel engine using a mixed oil obtained by mixing petroleum-based fuel oil and non-refined waste oil as a fuel,
On a flywheel that is driven to rotate in synchronization with the rotation of the engine, a tooth for generating a rotation pulse signal and a detection reference portion that exists at a position corresponding to the detection reference position of the crank angle are provided. A rotation angle sensor that detects the presence of a detection reference unit and outputs a rotation pulse signal of the flywheel, a pulse width measurement unit that measures a pulse width of the rotation pulse signal output from the rotation angle sensor, and The rotation pulse signal output from the rotation angle sensor is sequentially counted, and when the detection reference unit is detected, the rotation pulse counting means for setting the count value to zero, and the pulse width measuring means is configured to detect the pulse width. A cylinder specifying means for specifying which cylinder of the plurality of cylinders has a combustion abnormality based on the count value when an abnormality is detected is provided. Rotation stability detector of diesel engines.   A diesel engine comprising the diesel engine rotation stability detecting device according to claim 1. A method for detecting the rotational stability of a diesel engine using a mixed oil obtained by mixing petroleum-based fuel oil and non-refined waste oil as fuel,
The rotation angle sensor detects the presence of a detection reference portion located at a position corresponding to a detection reference position of a rotation pulse signal generation tooth and a crank angle of a flywheel that is driven to rotate in synchronization with engine rotation. Outputting a wheel rotation pulse signal;
A step of measuring a pulse width of the rotation pulse signal output from the rotation angle sensor;
The rotation pulse counting means sequentially counts the rotation pulse signals output from the rotation angle sensor, and detects the detection reference unit to make the count value zero;
The cylinder specifying means includes a step of specifying which of the plurality of cylinders has a combustion abnormality based on the count value when the pulse width measuring means detects the abnormality of the pulse width. A method for detecting the rotational stability of a diesel engine.

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