JPS60116859A - Method of improving starting performance of diesel engine - Google Patents

Abstract

PURPOSE:To prevent drop of voltage and to thereby improve the starting performance of a Diesel engine, by supplying current only to a glow plug at the time of operating a starter while stopping current supply to an intake-air heating, electric heater disposed in an intake passage, and supplying current to said heater when the starter is not in operation. CONSTITUTION:When a key switch 12 is closed in starting an engine, relay switches 13, 9 are closed in case that the temeperature of cooling water detected by a water-temperature sensor 22 is lower than a predetermined value, and current is supplied to a glow plug 10 and an intake-air heating, electric heater 18, so that air in a combustion chamber 4 and an intake passage 17 is heated. Subsequently, when a starter switch 23 is closed after confirmation of the fact that a ''start OK'' indicator 20 is lighted after passing of a predetermined time T1, only a relay switch 19 is opened and current supply to the heater 18 is stopped. At the same time, a starter is set into operation at a rated voltage and the engine 1 is started. During the above while, the glow plug 10 is heated continuuously for promoting vaporization and ignition of fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for improving the startability of a diesel engine used in 11 vehicles such as automobiles, and particularly relates to a method for improving the startability of a diesel engine used in 11 vehicles such as automobiles, and particularly for a diesel engine using a glow plug and an electric heater for heating intake air. Relates to a method for improving startability.

Background of the invention White M d1 city axis line...l, \L'', h Suho cut; 7
As a method for improving the startability of the R■-Neseki, especially when it is cold, there is a method of heating the air in the combustion chamber and the fuel injected into the combustion chamber using a glow plug installed in the combustion chamber.
BACKGROUND ART Conventionally, a method of preheating intake air using an electric heater provided in an intake passage has been known, and each of these two methods has advantages and disadvantages.

In other words, in the method using glow plugs, since the power consumption of the glow plugs is small, even if the glow plugs are energized while the starter is operating, the voltage of the battery power supply that supplies current to the starter and glow plugs is low. Glow plugs do not fall down and have excellent quick heating properties, which shortens the warm-up time and the time it takes for a diesel engine to fully explode. Since the heat generation capacity of the diesel engine is small, even if electricity is continued to be applied to the diesel engine after the diesel engine completes tIA and this generates heat, it does not have much effect, reducing the blow-up time of the diesel engine and vR) 4) Severe & γ
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Similar to the method using glow plugs, the method using an electric heater for heating intake air shortens the time required for the Deville engine to fully explode, and also shortens the blow-up time and reduces white smoke during and after blow-up. Emissions will be reduced, but
Electric heaters consume more power than glow plugs,
For this reason, if the electric heater is energized while the starter is operating, the voltage of the battery power source, which is the common power source for the starter and the electric heater, will drop, and the starter will not operate at the rated voltage (this will cause the diesel engine to There is a possibility that the startability of the engine may actually deteriorate.

Purpose of the Invention The present invention uses a glow plug and an electric heater for heating intake air (71), and takes advantage of the respective advantages of a method for improving startability using a glow plug and a method for improving startability using an electric heater for heating intake air. It is an object of the present invention to provide a method for improving the startability of a diesel engine, which can improve the startability of a diesel engine and reduce white smoke emission m at the time of startup.

According to the present invention, the above-mentioned object is to provide a method for improving startability of a diesel engine having a glow plug in a combustion chamber and an electric heater for heating intake air in an intake passage. energization to the electric heater for heating the intake air is stopped and only the glow plug is energized while the electric heater for heating the intake air is running, and the electric heater for heating the intake air is energized when the starter is not operating. This is achieved by a method for improving startability of diesel engines.

Effects of the Invention According to the method for improving startability of a diesel engine according to the present invention, the glow plug and the electric heater for heating the intake air are used together, so that either the glow plug or the electric heater for heating the intake air can be used independently. The startability of the diesel engine is further improved compared to when the engine is used, and the amount of white smoke emitted at the time of starting is reduced. Moreover, while the starter is operating, only the glow plug is energized and the intake air is Since power supply to the electric heater for heating is stopped, there is no possibility that the starter will not operate at the rated voltage due to insufficient power of the battery power source, and the operation of the starter will not be inhibited.

DESCRIPTION OF THE EMBODIMENTS The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a startability improving device used to carry out the method for improving startability of a diesel engine according to the present invention. In the figure, 1 indicates a diesel engine, which sucks air into a combustion chamber 4 through an intake boat 3 that is opened and closed by an intake valve 2, and injects light oil from a fuel injection nozzle 5. A mixture of fuel and air in the combustion chamber 4 is compressed by the piston 6 and ignited, and the burned gas generated in the combustion chamber 4, that is, the exhaust gas, is The exhaust gas is discharged to the outside of the combustion chamber 4 through an exhaust port 8 that is opened and closed by an exhaust valve 7.

A glow plug 10 may be installed in the combustion chamber 4 to supply current from a battery power source 11 to the diesel engine 1.
The power is selectively supplied through a series circuit of a key switch 12 and a relay switch 13.

The intake boat 3 includes an intake passage 1 configured by an intake manifold 14, an intake passage member 15, and an intake tube 16.
7 is connected in communication, and the intake boat has an intake passage 1.
Air is sent through 7.

An electric heater 18 for heating intake air is provided in the intake passage member 15.
is provided. The electric heater 18 is equipped with an electric heating element such as a metal wire electric resistance heater or a ceramic heater, and selectively receives current from the battery power source 11 through a series circuit of a key switch 12 and a relay switch 19'. is being supplied to.

Between relay switches 13 and 19 11JI and start O
The blinking of the K display 20 is controlled by the control device 21. The control device 21 receives information regarding the cooling water temperature of the diesel engine 1 from the micro temperature sensor 22, and information regarding whether or not the starter (not shown in the diagram of the diesel engine 1) is in operation from the starter switch 23. Based on this information, the relay switches 13 and 1 are set according to the switch 0-1 as shown in FIG.
9 and the blinking of the start OK indicator 20.

Next, an example of the procedure for improving the startability of a diesel engine according to the present invention will be described with reference to gear 70-1 shown in FIG.

The routine shown in FIG. 2 begins when the key switch 12 of the engine 1 is closed.

First, in step 1, it is determined whether the temperature of the cooling water of the diesel engine 1 detected by the water temperature sensor 22 is below a predetermined value.

When the coolant temperature is below the predetermined value, the process proceeds to step 2, whereas when the coolant temperature is not below the predetermined value, the process proceeds to step 4.

In step 2, relay switches 13 and 19 are closed. When the relay switch 13 is closed, the current from the battery power source 11 is supplied to the glow plug 10, and when the relay switch 19 is closed, the current from the battery power m11 is supplied to the electric heater 18 for heating the intake air. When current is supplied to each of the glow plug 10 and the electric heater 18, both generate heat, the glow plug 10 heats the air in the combustion chamber 4, and the electric heater 18 heats the air in the intake passage 17. Heat.

After step 2, the process proceeds to step 3, in which it is determined whether a predetermined time T+ seconds has elapsed since the relay switches 13 and 19 were each closed. A predetermined time T after relay switches 13 and 19 are closed
If + seconds have not elapsed, step 3 is repeatedly executed, and when a predetermined time of 4-1 seconds has elapsed since the relay switches 13 and 19 were closed, the process advances to step 4.

In step 4, the start OK indicator 20 is energized, lights up, and informs the driver that intake air heating has been completed.

After step 4, the process proceeds to step 5, in which it is determined whether the starter switch 23 is closed and the starter is activated.

If the starter is not operating, step 5 is repeated; if the starter is operating, the process proceeds to step 6.

In step 6, the power supply to the start OK indicator 20 is stopped and the light is turned off, and the relay switch 1 is turned off.
9 will be held. When the relay switch 19 is closed, power supply to the electric heater 18 is stopped. When the starter is operating, the electricity to the electric heater 18 is stopped, thereby avoiding a voltage drop in the battery power supply 11, the starter operates at the rated voltage, and the diesel engine 1 is then started. . In addition, glow plug 1
0 generates heat by being supplied with current from the battery power source 11 even when the starter is operating, so that the glow plug receives liquid fuel injected into the combustion chamber 4 from the fuel injection nozzle 5 as the starter operates. Promotes vaporization and the creation of a mixture with good ignitability.

After step 6, the process proceeds to step 7, in which the starter switch 23 is pressed to determine whether or not the starter has finished operating.

If the operation of the starter has not been completed, step 7 is repeatedly executed, and if the operation of the starter has been completed, the process advances to step 8.

In step 8, relay switch 13 is opened, whereas relay switch 19 is closed. As a result, the energization to the glow plug 10 is stopped, the energization to the electric heater 18 is restarted, and the electric heater 18 heats the intake air.

After step 8, the process advances to step 9. In step 9, the relay switch 19 is closed and the temperature rises from ℃ to 12
A determination is made as to whether or not seconds have elapsed. If the predetermined time of 12 seconds has not elapsed since the relay switch 19 was closed, step 9 is repeatedly executed, and the relay switch 1 is closed.
Predetermined time after closing] When 2 seconds have elapsed, proceed to step 10.

In step 10, the relay switch 19 is heard,
Power supply to the electric heater 18 is stopped.

By executing the routine as described above, the glow plug 10 and the electric heater 18 are activated before the starter is activated.
While the starter is operating, the intake air and fuel are heated only by the glow plug 10, and after the starter has finished operating, that is, after the diesel engine 1 has completely exploded, the electric heater 18 Intake air heating is performed only by

As mentioned above, when the intake air is heated by the glow plug and the electric heater before the starter is activated, the synergistic effect of the ignition promotion effect of the air-fuel mixture by the glow plug and the TR effect of the intake air temperature by the electric heater In particular, the starting time during cold starting is considerably shortened. When only electric heaters are used, a large amount of power is generally required to obtain a sufficient intake air heating effect;
Because the electric heater and glow plug are used together, the electric heater does not need to heat the intake air when it is used alone, so the total electricity of the electric heater and glow plug is 2J. The power required is less than that required when the heater is used alone. Further, due to the effect of promoting ignition of the air-fuel mixture by the glow plug and the effect of reducing white smoke by heating the intake air by the electric heater, a significant reduction in the amount of white smoke emission and a shortening of the blow-up time of the diesel engine are achieved.

In the above-described embodiment, the glow plug and the electric heater are activated prior to starting the starter, but the intake air amount heating performed prior to the activation of the starter may be performed only by the glow plug. Often, after the starter has finished operating and the diesel engine has completely exploded, a glow plug may also be activated in addition to the electric heater. While the starter is in operation, it is sufficient that the electric current to the electric heater is stopped and only the glow plug is energized.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. This will be clear to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram, not showing an embodiment, of a startability improving device used to implement the method for improving startability of a diesel engine according to the present invention, and FIG. Flowchart 1 showing an example of the implementation procedure
− is. 1... Diesel engine, 2... Intake valve, 3... Intake boat, 4... Combustion plan, 5... Fuel injection nozzle,
6...Piston, 7...Exhaust valve, 8...Exhaust bow)-, 1'O...Glow plug, 11...Battery power supply, 12...Key switch, 13...Relay Switch, 14...Intake manifold small, 15...Intake passage member, 16...Intake tube, 17...Intake passage, 18...Electric heating type % type % OK indicator for intake air heating , 21...control device, 22...water temperature sensor. 23...Starter switch Figure 1 22 Figure 2

Claims (1)

[Claims] In a method for improving startability of a diesel engine having a glow plug in a combustion chamber and an electric heater for heating intake air in an intake passage, the electric heater for heating intake air is energized while the starter is operating. A method for improving startability of a diesel engine, characterized in that the starter is stopped and only the glow plug is energized, and the intake air heating electric heater is energized when the starter is not operating.