JPS60190657A - Fuel supply control device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To increase a quantity of intake air to an engine and improve its output performance, by equipping to the engine an intake air temperature detecting means, which detects a temperature of the intake air, and a fuel temperature regulating means which regulates a temperature of fuel. CONSTITUTION:The main unit of an eigine 1 provides in its intake passage 2 a main injection valve 4 in the vicinity of an intake valve 3. The intake passage 2 provides in its upstream side a subinjection valve 5. The intake passage 2 provides an intake air temperature sensor 6 generating analog voltage in accordance with a temperature of intake air. A fuel supply pipe 7 provides a fuel temperature sensor 8 generating analog voltage in accordance with a temperature of fuel. A control circuit 11, processing each output signal of the intake air temperature sensor 6 and the fuel temperature sensor 8, performs control or the like of a temperature controller 10. In this way, a cooling effect of the intake air can be improved in the engine and its output performance is improved because the temperature of the fuel additionally injected from the subjection valve 5 is accurately regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a fuel injection timing control device for an internal combustion engine which is provided with a sub-injection valve for cooling intake air.

BACKGROUND OF THE INVENTION Internal combustion engines are already known in which, in addition to a main injection valve provided for each cylinder, a sub-injection valve is provided upstream of an intake passage, for example, near a surge tank or a throttle body. The fuel injection from the sub-injector cools the intake air, improving charging efficiency, and thus improving output performance. In other words, depending on the conditions, the intake air temperature may drop and the desired purpose may be achieved, but what is important here is that the fuel particles injected into the intake air from the sub-injector reliably remove heat from the air. By atomizing and vaporizing the air, the air is cooled and the weight of the intake air can be increased. To achieve this, a condition is required in which the temperature of the fuel particles injected into the intake air becomes lower than that of the air before reaching the combustion chamber, and unless this condition is met, the heat from the air to the fuel particles is No inflow is expected, and no reduction in intake air temperature can be expected. Conventionally, the temperature relationship between the air and fuel particles has been left to its own devices, and depending on the configuration of fuel piping, operating conditions, etc., there may be regions where the fuel temperature is much higher than the intake air temperature. However, there was a problem in that the cooling effect of the intake air was reduced.

Purpose of the Invention The purpose of the present invention is to solve the problems of the conventional type described above.
By controlling the temperature of the fuel supplied from the auxiliary fuel injection valve according to the intake air temperature, which varies depending on the operating conditions, etc., and reliably creating conditions that promote heat transfer from the air to the fuel particles, the temperature of the fuel supplied from the auxiliary fuel injection valve is controlled. This increases the atomization and vaporization rate from when the additional fuel is injected until it reaches the combustion chamber, increasing the amount of intake air.

The purpose is to improve output performance.

Structure of the Invention In order to achieve the above-mentioned object, the present invention provides an internal combustion engine which includes a main injection valve provided for each cylinder and a sub-injection valve provided in common for each cylinder at the upstream portion of the intake passage. The engine is provided with an intake air temperature detection means for detecting the intake air temperature of the engine, and a fuel temperature adjustment device for adjusting the temperature of the fuel supplied to the sub-injection valve according to the intake air temperature. A fuel supply device for an internal combustion engine is provided.

Example Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a diagram for explaining the process in which fuel particles injected from the sub-injection valve 6 vaporize. The fuel particles injected from the sub-injection valve 5 take heat from the air while riding the air flow from point 8 to point b, and gradually vaporize from low-boiling point components, resulting in smaller fuel particles and atomization. promoted. Further, the same process occurs from point b to point 0, and vaporization is completed at point d, turning into a gas. In other words, it is not preferable for the vaporization of the fuel particles to be completed either upstream or downstream of point d.

FIG. 2 is also a graph for explaining the process of vaporizing fuel particles. In FIG. 2, the pressure and temperature of the fuel injected by the sub-injection valve 5 are expressed as Pl and TI.

The pressure and temperature inside the intake pipe where fuel is injected are P2+T2+
Characteristics indicating the boiling point (vaporization point) of each fuel component with different distillation properties are A, B, and O, respectively.

D is given. In the state of P,, Tl, the fuel injected under the pressure condition of P2 is separated into an A component which becomes a gas and a B-D component which remains a liquid. Of these, some of the components B to D will collide with the pipe wall and become liquid fuel, while others will become droplets and float in the air, depending on the fuel pressure, the shape of the injection valve, the conditions on the intake air flow side, etc. . Here, the intake air temperature is T
2, the fuel present in the form of droplets follows the aforementioned vaporization process while taking heat from the air, thereby cooling the intake air.

As already mentioned, the important thing for the fuel particles to remove heat from the air and cool the intake air is to
2) The condition Tl is satisfied in the intake pipe, and even if fuel with a temperature much higher than T2 is injected into the upstream part of the intake pipe through the sub-injection valve 5, the condition Tl is satisfied in the intake pipe. It is almost impossible to follow the process of removing heat, vaporizing the fuel itself, and cooling the air. On the other hand, if the temperature T1 of the fuel is too low, vaporization may not be completed even when the fuel reaches the engine coolant 3.

That is, the difference T2 Tlc > o) is preferably within an appropriate range.

In the present invention, the temperature of the fuel is adjusted so that the difference T2-T1 is within an appropriate range.

FIG. 3 is an overall schematic diagram showing a first embodiment of the fuel supply control device for an internal combustion engine according to the present invention. In Figure 3,
A main injection valve 4 is provided in the vicinity of the intake valve 3 in the intake passage 2 of the engine body 1 . There are as many main injection valves 4 as there are cylinders. Further, a sub-injection valve 5 is provided upstream of the intake passage 2, for example, near a surge tank or a throttle body. Note that this sub-injection valve 5 is common to each cylinder. Further, the intake passage 2 is provided with an intake temperature sensor 6 that generates an analog voltage according to the intake air temperature THA. A fuel temperature sensor 8 that generates an analog voltage according to the fuel temperature THF is provided in a fuel supply pipe 7 that communicates only with the sub-injection valve 5, and a fuel supply pipe that communicates with both the main injection valve 4 and the sub-injection valve 50! :lVc is provided with a temperature controller 10 that controls the temperature of the fuel.

The degree controller 10 may have the functions of a heater using electric heat or the like and a cooler that cools the fuel by introducing cold air from an air conditioner, for example, and each may be installed independently. Good too.

The control circuit 11 includes an intake temperature sensor 6 and a fuel temperature sensor 8.
It processes each output signal to control the temperature controller 10, etc., and is constituted by, for example, a microcomputer. In addition, in FIG. 3, 12 is a fuel tank, and 13 is a fuel pump.

The operation of the control circuit of FIG. 3 will be described with reference to chart 70 of FIG. 4. The routine shown in FIG. 4 may be an interrupt routine that starts at a predetermined time or every predetermined crank angle, or may be a part of the main routine. First, proceed from start step 401 to step 402 to import intake air @THA data from sensor 6 and step 4.
At step 03, the fuel temperature data THF is taken from the fuel temperature sensor 8.

Next, in step 404, these temperature differences ΔTH←
Calculate THA-THF'i. Step 405゜406
It is determined whether the temperature difference ΔTH is in the range of 5 to 20°C.

When the difference ΔTH is less than 5° C., the cooling drive signal So is sent to the cooler of the temperature controller 10 in step 407 to lower the temperature of the fuel. When the difference ΔTH exceeds 20°C, the heating drive signal 5Ht is activated in step 4 (18).
The fuel is sent to the heater of the temperature controller 10 to raise the temperature of the fuel. If the temperature difference ΔTH is in the range of 5 to 20°C, the process advances to step 409 and the drive signals 8o and SH
Stop sending both. The routine then ends at step 410.

In this way, electrification and vaporization within the intake pipe are performed efficiently, and the cooling effect of the intake air is enhanced, which is the aim of the fuel supply method in which the auxiliary fuel injection valve is installed in the upstream part of the intake pipe. The effect of improving output performance will increase. In addition, by performing fuel injection under conditions in which atomization and vaporization of fuel particles can be expected, growth of fuel particles in the injection wave, that is, coarsening, and liquid film formation due to collision with pipe walls, etc., can be suppressed. It is also possible to prevent the formation of liquid film fuel, which causes distribution sensitization.

FIG. 5 is an overall schematic diagram showing a second embodiment of the fuel supply control device for an internal combustion engine according to the present invention. The difference in FIG. 5 is that a temperature controller 101 is provided in the fuel supply pipe 7 instead of the temperature controller 100 in FIG. , this temperature controller 1σ is the temperature controller 10 in FIG.
Although it has a similar configuration, only the temperature of the fuel communicating with the sub-injector 5 is controlled. As a result, it is possible to prevent a rise in fuel temperature on the main injection valve 4 side, and therefore, it is possible to prevent poor restartability at high temperatures. In other words, it is possible to prevent the generation of paper due to a rise in fuel temperature, so it is possible to prevent deterioration in restartability due to an overly lean mixture.

Note that the operation of the control circuit 10 in FIG. 5 is also executed according to the flowchart in FIG. 4.

FIG. 6 is an overall schematic diagram showing a third embodiment of the fuel supply control device for an internal combustion engine according to the present invention. In FIG. 6, a heater 10' is provided in the fuel supply pipe 7, which heats only the fuel on the sub-injection valve 5 side, and a cooler 1σ"° is provided in the fuel supply pipe 9. As a result, the fuel on both sides of the main and auxiliary injection valves 4.5 is cooled.

As a result, as in the second embodiment, the fuel on the main injection valve 4 side is not heated during engine operation, but in addition, the main injection valve 4 side is cooled by the cooler 10° II. , the high temperature restartability is improved compared to the second embodiment.

Note that the operation of the control circuit 10 in FIG. 6 is also executed according to the flowchart in FIG. 4.

In addition, as the intake temperature parameter in the above example,
Parameters that are correlated with the intake air temperature, such as the wall temperature of the intake passage and the ambient temperature in the engine room, may also be used.

As described in detail, according to the present invention, since the temperature of the additional fuel from the sub-injector is appropriately adjusted, the cooling effect of the intake air can be improved, and therefore the output performance can be improved.

[Brief explanation of drawings]

1 and 2 are diagrams and graphs explaining the vaporization process of fuel particles injected from the sub-injector, and FIG. 3 shows a first embodiment of the fuel supply control device for an internal combustion engine according to the present invention. 4 is a flowchart explaining the operation of the control circuit of FIG. 3, and FIGS. 5 and 6 are a second diagram of the fuel supply control device for an internal combustion engine according to the present invention. FIG. 7 is an overall schematic diagram showing a third embodiment. 1... Engine body, 2... Intake passage (intake pipe), 3
...Intake valve, 4...Main injection valve, 5...
Sub-injection valve, 6... Intake temperature sensor, 8... Fuel temperature sensor, 10.1σ, 1σ i oll+... Temperature controller, 11... Control circuit. Patent Applicant Toyota Motor Corporation Patent Application Representative Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Masashi Matsushita Patent Attorney Akira Yamaguchi Patent Attorney Masaya Nishiyama Figure 1 Figure '2 Pressure 3 Figure 1 Figure 5 Figure 13

Claims (1)

[Scope of Claims] 1. In an internal combustion engine equipped with a main injection valve provided for each cylinder and a sub-injection valve provided in common for each cylinder in the upstream portion of the intake passage, the intake air temperature of the engine Fuel supply control for an internal combustion engine, comprising an intake air temperature detection means for detecting the intake air temperature, and a fuel temperature adjustment means for adjusting the temperature of the fuel supplied to the sub-injection valve according to the intake air temperature. Device. 2. Fuel supply control for an internal combustion engine according to claim 1, wherein the fuel temperature adjusting means adjusts the temperature of the fuel so that the difference between the intake air temperature and the fuel temperature is within a predetermined range. Device. 3. Fuel supply control for an internal combustion engine according to claim 1, wherein the fuel temperature adjustment means includes a heating/cooling device provided in a fuel passage communicating with both the main injection valve and the sub-injection valve. Device. 4. The fuel supply control device for an internal combustion engine according to claim 1, wherein the fuel temperature adjusting means includes a heating/cooling device provided in a fuel passage communicating only with the sub-injection valve. 5. The fuel temperature adjustment means includes a heater provided in a fuel passage communicating only with the auxiliary injection valve, and a cooler provided in a fuel passage communicating with both the main injection valve and the auxiliary injection valve. A fuel supply control device for an internal combustion engine according to claim 1.