JP2009167964A - Start control device for internal combustion engine - Google Patents

Abstract

An internal combustion engine which is driven by burning a fuel mixture of gasoline and alcohol, and which has a further improved startability at a low temperature, is provided.
A heater 12 provided downstream of an auxiliary fuel injection valve 11 in an intake passage 3, a second fuel pressure pump 23 for applying pressure to a mixed fuel 21 supplied to the auxiliary fuel injection valve 11, an engine A water temperature sensor 41 for detecting the temperature Tw of the cooling water in the water jacket of the main body 1 and, if the temperature of the cooling water detected by the water temperature sensor is equal to or lower than the first predetermined value T1, the auxiliary is based on the first data map. When the fuel injection valve 11 and the second fuel pressure pump 23 are controlled and the temperature of the cooling water detected by the water temperature sensor 41 is equal to or lower than a second predetermined value T2 lower than the first predetermined value, the second And an electronic control unit 40 for controlling the heater 12 based on the data map.
[Selection] Figure 1

Description

  The present invention relates to a start control device for an internal combustion engine.

  In recent years, automobiles including an internal combustion engine that burns and drives a mixed fuel obtained by mixing gasoline and alcohol (for example, ethanol) have been developed from the viewpoint of environment and energy. Since alcohol is a single component and its boiling point is higher than that of low-boiling components contained in gasoline, starting an internal combustion engine in a low temperature range, for example, minus 15 ° C. or less, compared with an internal combustion engine driven by burning conventional gasoline The nature was bad. Specifically, alcohol has a smaller stoichiometric air-fuel ratio than gasoline, and it is necessary to send a large amount of alcohol into the cylinder of the internal combustion engine, so that the ignition plug provided in the cylinder is wet with alcohol and does not ignite There was sex. Also, alcohol has a higher latent heat of vaporization than gasoline and cools the surroundings of the alcohol when it is vaporized, which is one factor that makes the startability of the internal combustion engine worse than an internal combustion engine driven by burning conventional gasoline. there were. Therefore, various improvements have been made to improve the startability of the internal combustion engine at a low temperature.

  For example, Patent Document 1 discloses a bypass tank that bypasses a main air passage composed of a surge tank and an intake manifold provided in an intake pipe of an engine and supplies air to each cylinder, a bypass passage provided in the bypass passage, A fuel vaporizer for an internal combustion engine comprising a fuel vaporizer comprising a sub-injection valve is described. In this fuel vaporizer for an internal combustion engine, control is performed so that the heater is energized in accordance with the operating state of the internal combustion engine.

JP 2006-194204 A

  In the fuel vaporization device for an internal combustion engine described in Patent Document 1, the startability of the internal combustion engine is improved to some extent by controlling the heater according to the operating state of the internal combustion engine to promote fuel vaporization. Further improvement of sex was desired.

  Therefore, the present invention has been proposed in view of the above-described problems, and is an internal combustion engine that is driven by burning a fuel mixture of gasoline and alcohol, and has a further improved startability at a low temperature. The purpose is to provide.

An internal combustion engine start control apparatus according to a first aspect of the present invention for solving the above-described problem is provided.
In a start control device for an internal combustion engine that can use a mixed fuel in which gasoline and alcohol are mixed, and controls the start of the internal combustion engine having an auxiliary fuel injection valve in the intake passage upstream of the main fuel injection valve,
Heating means provided on the downstream side of the auxiliary fuel injection valve in the intake passage;
Fuel pressure adjusting means for adjusting a fuel pressure which is a supply pressure of the mixed fuel;
Temperature detecting means for detecting the temperature of the internal combustion engine;
When the temperature detected by the temperature detecting means is equal to or lower than a first predetermined value, the fuel pressure adjusting means is controlled to operate the auxiliary fuel injection valve and increase the fuel pressure, and the temperature detecting means detects the temperature. And a control means for operating the heating means when the temperature of the cooling medium is equal to or lower than a second predetermined value lower than the first predetermined value.

An internal combustion engine start control apparatus according to a second invention for solving the above-described problem is
An internal combustion engine start control device according to a first invention,
The control means controls the fuel pressure adjusting means to increase the fuel pressure as the temperature detected by the temperature detecting means decreases.

An internal combustion engine start control device according to a third aspect of the present invention for solving the above-described problem is
An internal combustion engine start control device according to a second invention,
The control unit controls the fuel pressure adjusting unit based on a first data map, and the first data map indicates a relationship between the temperature and the fuel pressure created in advance for each mixing ratio of the alcohol. It is a map.

An internal combustion engine start control device according to a fourth aspect of the invention for solving the above-described problem is provided.
An internal combustion engine start control device according to any one of the first to third inventions,
The control means controls the heating means on the basis of a second data map, and the second data map includes the temperature created in advance and the state of the heating means for each mixing ratio of the alcohol. It is a map showing the relationship.

  According to the start control device for an internal combustion engine according to the present invention, when the temperature in the internal combustion engine is equal to or lower than the first predetermined value, the auxiliary fuel injection valve is operated and the fuel pressure is increased. Substantial increase in vaporization time due to injection (the distance between the auxiliary fuel injection valve and the cylinder of the internal combustion engine is longer than the distance between the main fuel injection valve and the cylinder of the internal combustion engine) When the temperature is lower than the second predetermined value lower than the first predetermined value, the heating means is further operated, so that the auxiliary fuel injection valve, the fuel pressure increase, and the heating means are improved. A reliable start can be achieved even at extremely low temperatures due to a synergistic effect.

  According to the start control device for an internal combustion engine according to the present invention, the fuel pressure is accurately adjusted according to the temperature in the internal combustion engine, so that the startability of the internal combustion engine can be improved efficiently.

  According to the start control device for an internal combustion engine according to the present invention, the first data map is a map showing the relationship between the temperature of the cooling medium and the pressure of the mixed fuel prepared in advance for each mixing ratio of alcohol. Thus, the fuel pressure can be appropriately adjusted according to the mixing ratio and temperature of the alcohol, and the startability of the internal combustion engine at a low temperature can be improved efficiently.

  According to the start control device for an internal combustion engine according to the present invention, the second data map is a map showing the relationship between the temperature of the cooling medium prepared in advance and the state of the heating means for each mixing ratio of alcohol. Thus, the control of the heating means can be appropriately adjusted according to the mixing ratio and temperature of the alcohol, and the load on the energy source for operating the heating means can be reduced.

  The best mode of a start control device for an internal combustion engine according to the present invention will be specifically described with reference to the drawings.

[First embodiment]
According to a first embodiment in which the start control device for an internal combustion engine according to the present invention is applied to an internal combustion engine that is driven by burning a mixed fuel containing ethanol and gasoline having a higher boiling point than a low boiling point component contained in gasoline. This will be described with reference to FIGS.
FIG. 1 is a diagram schematically showing a case where the start control device for an internal combustion engine is applied to an internal combustion engine having four cylinders, and FIG. 2 is a diagram showing a control flow thereof. FIG. 3 is a data map showing an example of the relationship between the temperature of the cooling water and the fuel pressure, and FIG. 4 is a data map showing an example of the relationship between the temperature of the cooling water and the heater current. 3 and 4, the solid line indicates the case where the ethanol concentration is 85% (E85), the one-dot chain line indicates the case where the ethanol concentration is 50% (E50), and the two-dot chain line indicates that the ethanol concentration is 20% (E20). ).

The start control device for an internal combustion engine according to the present embodiment is used for start control of an internal combustion engine that burns and drives a mixed fuel obtained by mixing alcohol, for example, ethanol and gasoline.
As shown in FIG. 1, the internal combustion engine start control device 50 includes a main fuel injection valve 4, an auxiliary fuel injection valve 11 for starting, a heater (heating means) 12, and the like. Examples of the mixed fuel include E20 having an ethanol concentration of 20%, E50 having an ethanol concentration of 50%, and E85 having an ethanol concentration of 85%.

  An engine body 1 that is an internal combustion engine includes an intake passage 3 that sucks air into each cylinder 2 of the engine body 1. The intake passage 3 is branched corresponding to each cylinder 2 of the engine body 1 and is branched to communicate with each of the cylinders 2, and a collecting portion 3b in which the branch portions 3a are gathered and extend upstream. Have

  The main fuel injection valve 4 is disposed in each of the branch portions 3 a for each cylinder in the intake passage 3. The auxiliary fuel injection valve 11 is located on the upstream side of the main fuel injection valve 4 and is disposed in the collecting portion 3 b of the intake passage 3. A heater 12 is disposed on the downstream side (branch portion 3a side) of the auxiliary fuel injection valve 11 in the collecting portion 3b of the intake passage 3. An electronically controlled throttle valve 6 is provided on the upstream side of the auxiliary fuel injection valve 11 in the collecting portion 3b of the intake passage 3. The heater 12 is operated by a battery (not shown).

  The mixed fuel 21 stored in the fuel tank 20 is fed to the main fuel injection valve 4 through the fuel injection pipe 5 by the first fuel pressure pump 22. The mixed fuel 21 stored in the fuel tank 20 is fed to the auxiliary fuel injection valve 11 by a second fuel pressure pump (fuel pressure adjusting means) 23.

The above-described start control device 50 for an internal combustion engine further includes an electronic control unit (hereinafter referred to as ECU) 40 which is a control means.
The ECU 40 includes a microcomputer including an input / output device, a storage device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter, and the like. The ECU 40 receives a detection signal of a water temperature sensor 41 that is a temperature detection means for detecting the temperature Tw of the cooling water (cooling medium) flowing in the water jacket of the engine body 1. Further, a starter motor 42 is connected to the ECU 40.

  The ECU 40 controls the auxiliary fuel injection valve 11 and the second fuel pressure pump 23 based on the cooling water temperature Tw when the cooling water temperature Tw detected by the water temperature sensor 41 is equal to or lower than the first predetermined value T1. In addition, when the temperature Tw of the cooling water detected by the water temperature sensor 41 is equal to or lower than a second predetermined value T2 lower than the first predetermined value T1, the heater 12 is further controlled based on the second data map. To do. Further, the ECU 40 controls the main fuel injection valve 4 and controls the heater 12 based on the second data map, and then injects the mixed fuel 31.

  Such control by the ECU 40 will be described with reference to FIGS.

  As shown in FIG. 2, first, in step S1, the temperature Tw of the cooling water in the water jacket of the engine body 1 detected by the water temperature sensor 41 is a first predetermined value T1, for example, minus 15 ° C. or less. It is determined whether it is. When the temperature Tw of the cooling water is equal to or lower than the first predetermined value T1, the process proceeds to step S2. On the other hand, when the temperature Tw of the cooling water is higher than the first predetermined value T1, the process is terminated as it is, and fuel injection control of a normal internal combustion engine is performed. That is, when the temperature Tw of the cooling water is higher than the first predetermined value T1, the first fuel pressure pump 22 and the first fuel pressure pump 22 and the main fuel injection valve 4 are injected as the normal control. The main fuel injection valve 4 is controlled.

  Subsequently, in step S2, a fuel pressure map (first data map) indicating the relationship between the temperature of the cooling water and the fuel pressure of the second fuel pressure pump 23, for example, a fuel pressure map shown in FIG. 3 is read. As shown in FIG. 3, on the low temperature side, the higher the ethanol concentration, the higher the fuel pressure. That is, at minus 22 ° C. or lower, the fuel pressure of the second fuel pressure pump 23 is set higher when the ethanol concentration is 50% or when the ethanol concentration is 85% than when the ethanol concentration is 20%. Furthermore, the fuel pressure of the second fuel pressure pump 23 is set higher when the ethanol concentration is 85% than when the ethanol concentration is 50%. That is, when the engine body 1 is started using the mixed fuel 21 having an ethanol concentration of 85% and the temperature Tw of the cooling water is in the first temperature region A1 that is higher than minus 15 ° C. Only the fuel injection valve 4 is set to operate. On the other hand, when the temperature Tw of the cooling water is in the second temperature region A2 which is a low temperature of minus 15 ° C. or less, the auxiliary fuel injection valve 11 is set to operate. Thereby, even when the temperature Tw of the cooling water is a low temperature of minus 15 ° C. or less, vaporization of the low boiling point component contained in the mixed fuel 21 can be promoted.

  In the subsequent step S3, the operation of the second fuel pressure pump 23 is adjusted so as to realize the fuel pressure read in step S2, and the process proceeds to step S4. In step S4, it is determined whether the temperature Tw of the cooling water in the water jacket of the engine main body 1 detected by the water temperature sensor 41 is a second predetermined value T2, for example, minus 24 ° C. or less. When the temperature Tw of the cooling water is equal to or lower than the second predetermined value T2, the process proceeds to step S5, and when not lower than the predetermined value T2, the process proceeds to step S7.

  Proceeding to step S5, a heater current map (second data map), for example, a heater current map shown in FIG. 4 is read in step S5. As shown in FIG. 4, in the low temperature region, the temperature region where the heater current (heater 12) is turned on is set wider as the ethanol concentration is higher. That is, in a low temperature region of minus 24 ° C. or less, the heater current is turned on even at a higher temperature when the ethanol concentration is 50% or when the ethanol concentration is 85% than when the ethanol concentration is 20%. Is set. Furthermore, the heater current is set to be ON at a higher temperature when the ethanol concentration is 85% than when the ethanol concentration is 50%. That is, when the engine body 1 is started using the mixed fuel 21 having an ethanol concentration of 85% and the temperature Tw of the cooling water is in the third temperature region B1 that is higher than minus 24 ° C., heating is performed. The heater 12 is set to be turned off. On the other hand, when the temperature Tw of the cooling water is in the fourth temperature region B2 which is a low temperature of minus 24 ° C. or lower, the heater 12 is set to be turned on. Therefore, even in the case where a large amount of ethanol having a high boiling point is contained in the mixed fuel 21, the inside of the intake passage 3 is heated by the heater 12, and thus the vaporization heat of ethanol can be obtained. The startability of the main body 1 can be improved.

  Subsequently, the process proceeds to step S6, where the heater current is turned on based on the heater current map read in step S5. That is, the heater 12 is energized according to the temperature Tw of the cooling water in the water jacket of the engine body 1 to heat the intake passage 3 and its surroundings.

  Then, it progresses to step S7 and it sets so that it may act | operate according to the cranking operation | movement at the time of a start injector start in this step S7. That is, based on the fuel pressure map read in step S2, the second fuel pressure pump 23 is controlled to inject the mixed fuel 32 from the auxiliary combustion injection valve 11 into the intake passage 3.

  Then, it progresses to step S9 and starting determination is performed in this step S9. If the engine has rotated, the process proceeds to step S10. If the engine has not rotated, the process returns to step S7.

  In step S10, the heater current (heater heater 12) and the start injector are set to the OFF state, the process is terminated, and the above-described fuel injection control of the internal combustion engine is performed.

  Therefore, according to the start control device 50 for an internal combustion engine according to the present embodiment, the heater 12 is controlled in accordance with the temperature Tw of the cooling water in the water jacket of the engine body 1 so that the auxiliary fuel injection valve 11 The heat of vaporization of the mixed fuel 32 injected into the intake passage 3 can be obtained from the heater 12, and the vaporized mixed fuel 33 can be supplied to each cylinder 2 of the engine body 1. Further, the mixture injected from the auxiliary fuel injection valve 11 to the intake passage 3 is controlled by controlling the auxiliary fuel injection valve 11 and the second fuel pressure pump 23 according to the temperature Tw of the cooling water in the water jacket of the engine body 1. The amount of the fuel 21 can be adjusted optimally. Further, since the distance between the auxiliary fuel injection valve 11 and the cylinder 2 of the engine main body 1 is longer than the distance between the main fuel injection valve 4 and the cylinder 2 of the engine main body 1, the mixed fuel injected from the auxiliary fuel injection valve 11 therebetween. The vaporization of 32 is accelerated until it is supplied into the cylinder 2 of the engine body 1.

  That is, when the temperature in the internal combustion engine is equal to or lower than the first predetermined value, the auxiliary fuel injection valve is operated and the fuel pressure is increased, so that a substantial increase in vaporization time and fuel pressure increase due to fuel injection from the upstream side When the temperature is lower than the second predetermined value lower than the first predetermined value, the heater is further operated, so that the auxiliary fuel injection valve, the fuel pressure rise, and the heater are improved. A reliable start can be achieved even at extremely low temperatures due to a synergistic effect.

  The first data map is a map showing the relationship between the temperature of the cooling water prepared in advance and the pressure of the mixed fuel in correlation with the mixing ratio of the alcohol, so that the auxiliary fuel injection is performed according to the mixing ratio of the alcohol. The amount of the mixed fuel 32 injected from the valve 11 can be adjusted, the vaporization of the low boiling point component contained in the mixed fuel 32 is promoted, and the startability of the engine body 1 at a low temperature is enhanced by the vaporization of the low boiling point component. it can.

  The second data map is a map showing the relationship between the temperature of the cooling water prepared in advance and the state of the heater 12 in correlation with the mixing ratio of the alcohol, so that the heater according to the mixing ratio of the alcohol 12 can be adjusted, and the load on the battery for operating the heater 12 can be reduced.

It is the figure which showed typically one Embodiment which applied the starting control apparatus of the internal combustion engine which concerns on this invention to the internal combustion engine which has four cylinders. It is a figure which shows the control flow of one Embodiment which applied the starting control apparatus of the internal combustion engine which concerns on this invention to the internal combustion engine which has four cylinders. It is a data map which shows an example of the relationship between the temperature of a cooling water, and a fuel pressure. It is a data map which shows an example of the relationship between the temperature of a cooling water, and heater current.

Explanation of symbols

1 Engine Body 3 Intake Passage 11 Auxiliary Fuel Injection Valve 12 Heater 21 Mixed Fuel 23 Second Fuel Pressure Pump 40 Electronic Control Unit (ECU)
41 Water temperature sensor

Claims (4)

In a start control device for an internal combustion engine that can use a mixed fuel in which gasoline and alcohol are mixed, and controls the start of the internal combustion engine having an auxiliary fuel injection valve in the intake passage upstream of the main fuel injection valve,
Heating means provided on the downstream side of the auxiliary fuel injection valve in the intake passage;
Fuel pressure adjusting means for adjusting a fuel pressure which is a supply pressure of the mixed fuel;
Temperature detecting means for detecting the temperature of the internal combustion engine;
When the temperature detected by the temperature detecting means is equal to or lower than a first predetermined value, the fuel pressure adjusting means is controlled to operate the auxiliary fuel injection valve and increase the fuel pressure, and the temperature detecting means detects the temperature. And a control means for operating the heating means when the temperature of the cooling medium is equal to or lower than a second predetermined value lower than the first predetermined value. . A start control device for an internal combustion engine according to claim 1,
The internal combustion engine start control device characterized in that the control means controls the fuel pressure adjusting means to increase the fuel pressure as the temperature detected by the temperature detecting means decreases. An internal combustion engine start control device according to claim 2,
The control means controls the fuel pressure adjusting means based on a first data map, and the first data map shows a relationship between the temperature and the fuel pressure created in advance for each mixing ratio of the alcohol. An internal combustion engine start control device characterized by being a map. An internal combustion engine start control device according to any one of claims 1 to 3,
The control means controls the heating means on the basis of a second data map, and the second data map shows the temperature created in advance and the state of the heating means for each mixing ratio of the alcohol. An internal combustion engine start control device characterized by being a map showing a relationship.

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