JP3135686B2 - Control device for alcohol engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for an alcohol engine which supplies an alcohol-containing fuel such as methanol to a combustion chamber.

[0002]

2. Description of the Related Art Conventionally, methanol (CH ₃ O)
An engine described in Japanese Patent Application Laid-Open No. 62-197614 is an example of an engine that supplies an alcohol-containing fuel such as H) to a combustion chamber to reduce pollution and replace gasoline.

[0003] That is, an engine operation is provided with a ventilation passage for leading gas (blow-by gas including evaporated alcohol gas) in the crank chamber to an intake passage, and opening / closing means interposed in the ventilation passage to open and close the ventilation passage. The opening / closing means is opened according to the above-mentioned alcohol evaporation state, and the blow-by gas containing the evaporated alcohol gas is returned from the ventilation passage to the intake passage, and the blow-by gas is supplied to the combustion chamber at one time. This is an alcohol engine configured to prevent engine stall (stall) caused by the above.

However, if the blow-by gas containing the evaporated alcohol gas is recirculated to the intake passage during operation of the engine, the blow-by gas acts as a disturbance. There was a problem that caused.

[0005]

SUMMARY OF THE INVENTION According to the first aspect of the present invention, the alcohol component evaporated in the crank chamber after the engine is stopped is introduced into the intake passage through the ventilation passage while preventing the engine operating condition from deteriorating. By refluxing,
An object of the present invention is to provide a control device for an alcohol engine that can prevent deterioration of the engine oil due to an increase in water content in the engine oil.

According to the invention of claim 2 of the present invention, in addition to the object of the invention of claim 1, by forming a ventilation passage with an existing blow-by gas passage, it is not necessary to form a separate passage. It is an object of the present invention to provide an alcohol engine control device that can simplify the configuration.

According to a third aspect of the present invention, in addition to the object of the first or second aspect of the present invention, a good lubricating performance is always provided by controlling the height of the suction port of the oil strainer. An object of the present invention is to provide a control device for an alcohol engine that can be maintained.

[0008]

According to a first aspect of the present invention, there is provided an alcohol engine for supplying an alcohol-containing fuel such as methanol to a combustion chamber, wherein a ventilation passage for leading gas in a crank chamber to an intake passage is provided. The alcohol engine control device includes an opening / closing means interposed in the ventilation passage for opening and closing the ventilation passage, and a control means for opening and controlling the opening / closing means at least after the engine stops.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the ventilation passage is set as a blow-by gas passage and the opening / closing means is connected to a PC.
A control device for an alcohol engine, wherein the control device is set to a V-valve and the control means controls the opening of the PCV valve for a predetermined period.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the suction port of the oil strainer upstream of the oil pump is provided differently in the height direction, and A water content detecting means for detecting the water content in the oil in the bread or a parameter relating to the water content is provided, and when the water content increases based on the output of the water content detecting means, the oil suction port is sucked from a low position to a high position. The present invention is characterized in that it is a control device of an alcohol engine provided with a change means for performing change control in a mouth.

[0011]

According to the first aspect of the present invention, the control means opens the opening / closing means provided in the ventilation passage at least after the engine stops. For this reason, during the operation of the engine, the alcohol accumulated in the engine oil evaporates due to the heat of the oil itself, and the evaporated alcohol gas is generated in the crank chamber. The evaporated alcohol gas is released after the engine is stopped. The air can be returned to the intake passage through the opened / closed means and the ventilation passage. As a result, it is possible to prevent deterioration of the engine oil due to an increase in the water content in the engine oil, and since the above-described recirculation of the evaporated alcohol gas is performed after the engine is stopped, deterioration of the engine operating condition (air-fuel ratio decrease). Fluctuation) can be prevented.

According to the second aspect of the present invention,
In addition to the effect of the first aspect of the present invention, the ventilation passage is set as a blow-by gas passage, and the opening / closing means is set as a PCV valve. There is an effect that can be formed. As a result, there is no need to form a separate passage, and there is an effect that the configuration can be simplified.

According to the third aspect of the present invention,
In addition to the effect of the first or second aspect of the present invention, when the amount of water increases based on the output of the above-mentioned water amount detecting means, the above-mentioned changing means changes the oil suction port from a low level to a high level. Control. When the oil temperature is low, the oil and alcohol components are separated, and water is present at the bottom of the oil pan. When the amount of water increases, the oil suction port is changed to a higher position, so that the oil strainer The engine oil can be satisfactorily sucked from the suction port, so that a sufficient oil film can be secured, and there is an effect that good lubrication performance can always be maintained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawing shows the control device of the alcohol engine,
In FIG. 1, an alcohol engine that supplies an alcohol-containing fuel such as methanol to a combustion chamber C has a cylinder head cover 3 mounted on a cylinder block 1 via a cylinder head 2, and moves between the cylinder head 2 and the cylinder head cover 3. A valve chamber 4 is formed.

An oil pan 6 is mounted on the lower crankcase 5 of the cylinder block 1 to form a crank chamber 7, while an intake valve 9 is provided on an intake port 8,
Exhaust valves 11 are provided in the exhaust ports 10, respectively, and these intake and exhaust valves 9, 11 are configured to be appropriately opened and closed by a valve operating device 12.

Further, an intake passage downstream of the air cleaner is connected to the throttle body 13.
A throttle valve 15 is disposed in a throttle chamber 14 inside the throttle chamber 15, and the throttle chamber 14 downstream of the throttle valve 15 is connected to a surge tank 16.

The above-mentioned surge tank 16 is formed integrally with the intake manifold 17 and connects an intake passage 18 downstream of the surge tank 16 to the above-mentioned intake port 8 while connecting an exhaust manifold 19 to the exhaust port 10. ing.

The blow-by gas passage 20 formed in the cylinder block 1 and the cylinder head 2
The blow-by gas passage 21 formed in the
The gas (blow-by gas containing evaporated alcohol gas) in the crank chamber 7 is led out to the surge tank 16 by the blow-by gas deriving buffer portion 22 formed on the inner surface of the top deck of the cylinder head cover 3 and the blow-by gas recirculation pipe 23. A ventilation passage 24 is formed.

A PCV valve 25 (here, PCV valve) as an opening / closing means for opening and closing the ventilation passage 24, more specifically, a base end of the blow-by gas recirculation pipe 23.
V stands for positive crankcase ventilation, which means a crankcase forced ventilation system.

In FIG. 1, reference numeral 26 denotes the throttle valve 1
5, a fresh air introduction passage for introducing fresh air from the upstream side to the valve operating chamber 4, 27 is a piston, 28 is a connecting rod,
29 is a crankpin of the crankshaft 30, 3
1 is a water jacket.

FIG. 2 shows an example of the above-described PCV valve 25, in which a valve casing 34 having an inlet port 32 and an outlet port 33 for blow-by gas is provided, and a valve chamber 35 between each of the above-mentioned ports 32, 33 is provided. A valve element 36 is provided, and the valve element 36 is configured to be opened and closed via an excitation coil 37 and a valve shaft 38.
When the valve 6 is opened (the state shown in FIG. 2), the blow-by gas from the inlet port 32 is led to the outlet port 33 through the valve chamber 35.

FIG. 3 shows an oil suction structure, in which an oil suction pipe 4 having an upper end connected to an oil pump.
0, and the lower end of the oil suction pipe 40 is connected to the lower suction pipe 41 and the higher suction pipe 42.
The lower suction pipe 41 is provided with a lower oil strainer 43 having a lower suction port, and the higher suction pipe 42 is provided with a high oil strainer 44 having a higher suction port.

A shield plate 45 having an L-shaped cross section is provided below the high-order oil strainer 44, and the above-described components 41 to 45 are connected to a baffle plate having an oil communication port 46 and an open top structure. Surrounded by 47.

Further, the above-mentioned low-order suction pipe 41
At a branch point 48 between the oil suction port 42 and the high-order suction pipe 42, an oil suction port switching valve 49 for switching and selecting an oil suction port is mounted, and at a predetermined position of the oil pan 6, the water content in the engine oil EO in the oil pan 6 is set. Alternatively, an oil temperature sensor 50 is attached as a moisture amount detecting means for detecting a parameter related to the moisture amount (in this embodiment, the moisture amount is alternately detected by the oil temperature).

FIG. 4 shows a control circuit of the control device for the alcohol engine. The CPU 60 determines ON / OFF signals from the ignition switch 51, the oil temperature T from the oil temperature sensor 50, and the presence or absence of methanol attached to the fuel tank. The PCV valve 25 and the oil inlet switching valve 49 are drive-controlled according to a program stored in the ROM 53 based on various necessary signal inputs such as a detection signal from the methanol sensor 52 to be detected, and the RAM 54 sets the oil inlet from a low position. Necessary data such as an oil temperature set value To when switching to the high position and an oil temperature set value T1 when switching the PCV valve 25 from closed to open are stored.

Here, the CPU 60 controls the opening of the PCV valve 25 when the oil temperature T becomes higher than the predetermined temperature T1 based on the output of the oil temperature sensor 50 after the engine is stopped. And a changing means for controlling the change of the oil suction port from a low level to a high level based on the output of the water content detecting means (see the oil temperature sensor 50) when the water content increases.

In this embodiment, the oil temperature sensor 50 detects the oil temperature T in the oil pan 6 and the oil temperature in the engine oil EO in the oil pan 6. It also serves as both means for detecting a related parameter (for example, oil temperature) and a water content detecting means.

The operation of the control device for an alcohol engine thus configured will be described below with reference to the flowchart shown in FIG. 5 and the flowchart shown in FIG.
First, with reference to the flowchart of FIG. 5, the oil inlet switching control during engine operation will be described.

In a first step 61, the CPU 60 reads a signal from the methanol sensor 52, and in a next second step 62, the CPU 60 determines whether or not methanol is present, in other words, whether the fuel used is gasoline or alcohol-containing fuel. Is determined, and when there is methanol, the flow proceeds to the next third step 63,
When there is no methanol, the process shifts to another eighth step 68.

In the above-mentioned third step 63, the CPU 60 detects the current oil temperature T based on the input from the oil temperature sensor 50 disposed on the oil pan 6. Next, the fourth step 64
The CPU 60 compares the current oil temperature T with the oil temperature set value To, for example, 80 ° C., and when the oil temperature T is lower than To, proceeds to the next fifth step 65, where the oil temperature T> To When the temperature is high, the process proceeds to another eighth step 68.

In the above-described fifth step 65, the CPU 60 controls the oil suction port switching valve 49 to absorb the engine oil EO from the high oil strainer 44 and the high suction pipe 42. That is, when the oil temperature T is low, unburned alcohol, formic acid compounds as combustion products, water and the like are separated from the engine oil EO and are present at the bottom of the oil pan 6, so that oil absorption from a high place is prevented. By doing so, a sufficient oil film is maintained in various lubricated parts, and metal contact, abnormal wear, seizure, etc. of the lubricated parts are reliably prevented.

Since the boiling point of methanol is 64.5 ° C., the oil temperature set value To is changed from 80 ° C. to 6 ° C.
The temperature may be changed to 5 ° C. When the engine oil EO is to be absorbed from the above-mentioned high places, the high-order suction pipe 4
The L-shaped shielding plate 45 attached to 2 prevents the metal powder and other harmful substances and impurities from being directly sucked.

Next, at a sixth step 66, the CPU 60 determines the current oil temperature T based on the input from the oil temperature sensor 50 described above.
Is detected again. Next, in a seventh step 67, the CPU 60
Compares the magnitude relation between the current oil temperature T and the oil temperature set value To, and when the oil temperature is low and T <To, the fifth step 65
When the oil temperature is high and T> To, the process proceeds to the next eighth step 68.

In the eighth step 68, the CPU 60 controls the oil suction port switching valve 49 to absorb the engine oil EO from the low oil strainer 43 and the low suction pipe 41.

Next, the recirculation control of the blow-by gas containing the evaporated alcohol gas will be described with reference to the flowchart of FIG.

During the operation of the engine, the engine oil E
The alcohol accumulates in O, and the alcohol evaporates due to the heat of the engine oil EO itself, and an evaporated alcohol gas is generated in the crank chamber 7.

Therefore, in a first step 71, the CPU 60
Determines whether or not the engine is stopped based on the ON / OFF signal from the ignition switch 51. When the engine is stopped, the process proceeds to the next second step 72, while returning while the engine is operating.

In the above-described second step 72, the CPU 60 compares the current oil temperature T detected by the oil temperature sensor 50 with the oil temperature set value T1, and returns when the oil temperature is lower than T1 <T1. When the oil temperature is higher than T1 (the condition under which the evaporated alcohol gas is generated), the routine proceeds to the next third step 73.

In the third step 73, the CPU 60
The CV valve 25 is controlled to open. That is, the excitation coil 37 of the PCV valve 25 shown in FIG.
For a predetermined period.

As described above, the PCV valve 25 described above is used.
When the valve is opened, the blow-by gas containing the evaporated alcohol gas is supplied from the crank chamber 7 to the cylinder block 1 as indicated by a dotted arrow in FIG. 1 and a solid arrow in FIG.
Gas passage 20 on the side, the blow-by gas passage 21 on the cylinder head 2 side, the valve operating chamber 4, the buffer section 22 for deriving the blow-by gas, the inlet port 32 of the PCV valve 25, the portion opened by the valve body 36, the PCV valve The gas is returned to the surge tank 16 through the outlet port 33 of 25 and the blow-by gas return pipe 23.

As described above, the blow-by gas including the evaporated alcohol gas is returned to the intake system through the PCV valve 25 and the ventilation passage 24 which are opened after the engine is stopped and when the oil temperature is high. The deterioration of the engine oil EO due to an increase in the water content in the engine oil EO can be prevented, and the above-described recirculation of the evaporated alcohol gas is performed after the engine is stopped. Etc.) can be prevented.

The blow-by gas passages 20, 21 are used as the ventilation passages 24, and P
When the CV valve 25 is used, the ventilation passage 24 can be formed by effectively using the existing blow-by gas passages 20 and 21, so that there is no need to form a separate passage, and the configuration can be simplified. effective.

FIG. 7 shows another embodiment of the PCV valve.
The PCV valve 25A is provided with a valve casing 77 having an inlet port 75 and an outlet port 76 for blow-by gas, a thermoelement 78 on one side of the valve casing 77, and a seat 79 on the other side. The thermo element 78 is directly driven by the engine oil EO introduced into the oil chamber 80 between the valve casing 77 and the thermo element 78, and the seat 7
9 when the poppet valve 81 is separated from the high temperature,
The blow-by gas containing the evaporated alcohol gas is led out to the outlet port 76 through the opening 82 of the nozzle 9.

With this configuration, the oil temperature sensor 50
And the second step 72 in the flowchart shown in FIG. 6 can be omitted. However, since the blow-by gas is recirculated after the engine stops, it is necessary to provide, for example, an electromagnetic valve (not shown) in a part of the ventilation passage 24 and open the electromagnetic valve after the engine stops.

FIG. 8 shows still another embodiment of the PCV valve. This PCV valve 25B has a valve cover 86 provided with a blow-by gas inlet port 85, a valve casing 88 provided with a blow-by gas outlet port 87, and a valve casing 88 provided with a blow-by gas outlet port 87. Are bonded in an airtight manner,
8, a valve 89 and a gate valve 91 that is pivotally operated with a pin 90 as a fulcrum are provided, and the above-described gate valve 91 is heated by a heat wire 92 and a bimetal 93 that are heated corresponding to the output of the CPU 60. It is configured to open and close.

With this configuration, when the heat wire 92 is heated and the gate valve 91 is opened by the bimetal 93 (the state shown in FIG. 8) according to the flowchart shown in FIG. From the inlet port 85 to the outlet port 87 via the opening 91a of the gate valve 91 and the opening 89a of the valve 89.

FIG. 9 shows another embodiment of the oil suction structure. FIG. 9 is different from the structure of FIG. 3 in that a high-order oil strainer 44 is disposed downward, and this oil strainer 44 is connected to an oil communication port 95. 3 and a baffle plate having an open top structure surrounding only the peripheral portion of the high-order oil strainer 44 instead of the baffle plate 47 having an open top surface surrounding the elements 41 to 45 of FIG. The point is that the plate 97 is attached.

Even with this configuration, the same operation and effect as those of the previous embodiment shown in FIG. 3 can be obtained. Therefore, in FIG. 9, the same parts as those in FIG. Description is omitted.

FIG. 10 shows still another embodiment of the oil suction structure, in which an oil strainer 98 is attached to a lower end portion of an oil suction pipe 40 via a pipe 100 made of a shape memory alloy. An inverted L-shaped shielding plate 99 is continuously provided from a pipe immediately above the oil strainer 98, and the position of the oil strainer 98 is set to a higher position as shown by a virtual line β in FIG. As shown by α, the position of the oil strainer 98 is changed to a lower position.

With this configuration, the above-mentioned pipe 100 made of a shape memory alloy controls the oil suction port to change to a higher suction port when the amount of water in the oil pan 6 increases (when the oil temperature is low). Since it acts as a changing means, control of the CPU 60 can be omitted. As the shape memory alloy, an alloy corresponding to the above-mentioned temperature condition is selected from NiTi alloy, CuZnAl alloy and the like.

In the correspondence between the configuration of the present invention and the above-described embodiment, the intake passage of the present invention corresponds to the surge tank 16 of the embodiment, and the same applies to the opening / closing means and the PCV valves 25, 25A, 25B. Correspondingly, the control means is the CPU 6
0, the water content detecting means corresponds to the oil temperature sensor 50, and the changing means corresponds to the CPU 60 and the pipe 100 made of a shape memory alloy. However, the present invention is limited to only the configuration of the above embodiment. It is not something to be done.

For example, the switching valve 4 shown in FIGS.
Instead of 9, an oil temperature responsive bimetal valve or a thermoelement may be used.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a control device for an alcohol engine according to the present invention.

FIG. 2 is a sectional view of a PCV valve.

FIG. 3 is a sectional view showing an oil suction structure.

FIG. 4 is a block diagram of a control circuit.

FIG. 5 is a flowchart showing oil inlet switching control.

FIG. 6 is a flowchart showing the control of recirculation of blow-by gas containing evaporated alcohol gas.

FIG. 7 is a sectional view showing another embodiment of the PCV valve.

FIG. 8 is a sectional view showing still another embodiment of the PCV valve.

FIG. 9 is a sectional view showing another embodiment of the oil suction structure.

FIG. 10 is a sectional view showing still another embodiment of the oil suction structure.

[Explanation of symbols]

 C: Combustion chamber 6: Oil pan 7: Crank chamber 16: Surge tank 20, 21: Blow-by gas passage 24: Ventilation passage 25, 25A, 25B: PCV valve 40: Oil suction pipe 43, 44, 98 ... Oil strainer 50: Oil temperature sensor 60: CPU (control means, change means) 100: pipe (change means)

──────────────────────────────────────────────────続 き Continued on the front page (72) Shinichi Iwamoto, Inventor Shinichi 3-1, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Yoshio Fujita 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Matsu (58) Field surveyed (Int.Cl. ⁷ , DB name) F01M 13/00 F01M 11/03

Claims (3)

(57) [Claims] In an alcohol engine for supplying an alcohol-containing fuel such as methanol to a combustion chamber, a ventilation passage for guiding gas in a crank chamber to an intake passage, and an opening / closing opening and closing the ventilation passage interposed in the ventilation passage. A control unit for controlling the opening and closing of the opening / closing unit after the engine stops. 2. The alcohol engine according to claim 1, wherein the ventilation passage is set as a blow-by gas passage, the opening / closing means is set as a PCV valve, and the control means controls the opening of the PCV valve for a predetermined period. Control device. 3. An oil strainer upstream of an oil pump, wherein suction ports of the oil strainer are provided so as to be different from each other in a height direction, and a water content detecting means for detecting a water content or a parameter related to the water content in the oil in the oil pan is provided. 3. The control device for an alcohol engine according to claim 1, further comprising changing means for changing the oil suction port from a low level to a high level based on an output of the moisture detecting means.