JP2001115885A - Control device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationalize a fuel injection timing and fuel injection amount, in a diesel engine provided with an engine cooling water temperature increase promoting means, such as a heat accumulator, to introduce a part of high temperature cooling water from an engine cooling system and store it in a heat storing state for early warming up and feed cooling water, stored during starting of an engine, to an engine cooling system. SOLUTION: A main injection timing lead angle amount ΔIT is set according to a cooling water temperature Tw (110). A main injection amount increase fundamental value Δqf0 is set according to a lubrication oil temperature Tr (120). Further, A pilot injection time and a pilot injection amount are set according to a cooling water temperature Tw (140). When a difference between the cooling water temperature Tw and the lubrication oil temperature Tr exceeds a given value TO, a correction factor a for the main injection amount increase fundamental value ΔQfO is set according to the main injection timing lead angle ΔIT when a difference between the cooling water temperature Tw and the lubrication oil temperature Tr exceeds a given value TO, and a main injection amount increase value ΔQf=ΔQfO×α is determined (150-200).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a diesel engine, and more particularly to a control device for early warming-up of an engine.

[0002]

2. Description of the Related Art In order to promote warming-up of an engine, high-temperature engine cooling water is stored in a regenerator having a heat storage structure as disclosed in Japanese Patent Application Laid-Open No. H10-77839, and is stored in the regenerator at the next engine start. There has been proposed a cooling circuit for promoting warm-up operation using high-temperature engine cooling water.

On the other hand, conventionally, Japanese Patent Application Laid-Open No. 8-112195
As disclosed in Japanese Patent Application Laid-Open Publication No. H11-260, the fuel injection amount is increased according to the engine conditions at the time of a low temperature start to facilitate the start. In this case, any one of the cooling water temperature, the lubricating oil temperature, and the atmospheric temperature is used as the engine condition. In addition, since the combustion chamber temperature is low and the ignition delay period increases at low water temperature, it is common practice to advance the fuel injection timing in accordance with the water temperature to suppress misfire and white smoke.

Here, consider the fuel injection control of a diesel engine having a warm-up promoting means (engine cooling water temperature rise promoting means) such as a heat accumulator described in Japanese Patent Application Laid-Open No. 10-77839.

[0005] At the start when the cooling water in the regenerator keeps a high temperature, the high temperature of the cooling water flows from the regenerator, and the temperature of the cooling water of the engine body rises quickly, but the lubricating oil temperature rises. Is slow, and the lubricating oil temperature is considerably lower than the cooling water temperature.

In this case, since the cooling water temperature is close to the warm-up state, the temperature of the combustion chamber is high, and the ignition delay period is also close to the warm-up state. Therefore, the advance amount of the fuel injection timing may be small. However, since the lubricating oil temperature is low, the friction of the engine body is large. Therefore, a large increase in the fuel injection amount is required.

As described above, in a diesel engine having warm-up promoting means such as a regenerator, it is desirable to control the fuel injection timing in accordance with the cooling water temperature and the fuel injection amount in accordance with the lubricating oil temperature. .

Further, if the standing time until the next start is long, the temperature of the cooling water at the time of the start will drop to the outside air temperature as well as the lubricating oil temperature due to a decrease in the temperature of the cooling water in the regenerator. As described above, in the engine using the regenerator, the temperature difference between the cooling water and the lubricating oil does not have a uniform relationship at the time of startup and during warm-up. For example, even when the lubricating oil temperature is the same 20 ° C., the cooling water temperature may be 60 ° C. or 20 ° C. depending on the heat storage state.

In this case, if the fuel injection amount is set according to the lubricating oil temperature, the same injection amount will be obtained. However, since the cooling water temperature is different, the fuel injection timing is set differently. However, the ratio that can be converted from the fuel injection amount to the output generated by the engine,
That is, since the fuel consumption rate changes depending on the fuel injection timing and the cooling water temperature (combustion chamber wall temperature), when the fuel injection amount is controlled only in accordance with the lubricating oil temperature, the fuel injection amount is increased with respect to the required torque. Is too small, which leads to poor driving performance,
Conversely, there is a problem in that the amount of fuel injection is too large to generate black smoke and white smoke.

In order to solve such a problem, Japanese Patent Application Laid-Open No.
In the conventional fuel injection control described in 121195,
For the control of the fuel injection amount and the fuel injection timing, the definition of the temperature representing the warm-up state of the engine is not clear, and the difference in the fuel consumption rate due to the difference in the fuel injection timing is There was no technology to reflect on the settings.

[0011]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention relates to a diesel engine having a means for accelerating engine coolant temperature rise for early warm-up.
An object of the present invention is to prevent the deterioration of drivability and the deterioration of black smoke and white smoke by optimizing the control of the fuel injection timing and the fuel injection amount.

[0012]

According to the present invention, there is provided a control apparatus for a diesel engine having an engine cooling water temperature rise promoting means for early warm-up, as shown in FIG. A fuel injection timing advance amount setting means for setting the fuel injection timing advance amount according to the engine coolant temperature, a fuel injection amount increase value setting means for setting the fuel injection amount increase value according to the engine lubricating oil temperature, When the difference between the engine cooling water temperature and the engine lubricating oil temperature is equal to or greater than a predetermined value,
A correction means for setting a correction value for the fuel injection amount increase value in accordance with the fuel injection timing advance amount and correcting the fuel injection amount increase value is provided.

According to a second aspect of the present invention, there is provided a control apparatus for a diesel engine which includes an engine cooling water temperature rise promoting means for early warm-up and performs a pilot injection prior to a main fuel injection. As shown, pilot injection control means for controlling the pilot injection timing and pilot injection amount according to the engine coolant temperature, and main injection timing advance amount setting means for setting the main injection timing advance amount according to the engine coolant temperature And main injection amount increase value setting means for setting the main injection amount increase value in accordance with the engine lubricating oil temperature.

According to a third aspect of the present invention, in addition to the configuration of the second aspect of the invention, when the difference between the engine cooling water temperature and the engine lubricating oil temperature is equal to or more than a predetermined value, the main injection timing advance amount is adjusted. A correction means for setting a correction value for the main injection amount increase value and correcting the main injection amount increase value is provided (see FIG. 1B).

Here, as the engine cooling water temperature rise accelerating means, a part of the high-temperature cooling water is introduced from the engine cooling system and stored in a heat storage state as in the invention according to claim 4, and stored when the engine is started. It may be configured to include a regenerator for supplying the stored cooling water to the engine cooling system, or may be configured to include a heater for heating the engine cooling water as in the invention according to claim 5. May be performed.

[0016]

According to the first aspect of the present invention, the difference between the cooling water temperature and the lubricating oil temperature depends on the operation status of the cooling water temperature rise promotion means (the heat storage state of the cooling water in the heat accumulator and the state of the heater). Therefore, the fuel injection amount can be appropriately set even when the values differ, so that the drivability and the black smoke / white smoke do not deteriorate.

According to the second aspect of the present invention, when performing the pilot injection, the pilot injection timing, the pilot injection amount, and the main injection timing are controlled according to the cooling water temperature. The temperature in the cylinder can be appropriately set, so that no misfire occurs in the main injection. Also,
Since the main injection amount is controlled in accordance with the lubricating oil temperature, an appropriate fuel injection amount can be set in accordance with the friction of the engine body, and there is no deterioration in drivability and black smoke / white smoke.

According to the third aspect of the invention, in addition to the effect of the second aspect of the invention, the main injection amount can be corrected according to the difference between the cooling water temperature and the lubricating oil temperature. Is improved.

[0019]

Embodiments of the present invention will be described below. FIG. 2 is a configuration diagram of a diesel engine showing one embodiment of the present invention, and this will be described first.

An engine cooling water inlet pipe 2 and an engine cooling water outlet pipe 3 are connected to the engine body 1. A regenerator 4 is provided as a means for accelerating the engine coolant temperature rise for the purpose of early warm-up, and a part of the high-temperature engine coolant flowing out of the engine coolant outlet pipe 3 is supplied to the regenerator coolant inlet pipe. 5 to store the cooling water, and guide the cooling water kept warm from the regenerator cooling water discharge pipe 6 to the engine cooling water inlet pipe 2 when the engine is started.

Each cylinder of the engine body 1 is provided with a fuel injection nozzle 7. To this fuel injection nozzle 7,
High-pressure fuel is supplied from a common rail (fuel pressure accumulation pipe) 8. High pressure fuel is pumped to the common rail 8 from a supply pump 9 driven by an engine.

Here, the injection timing and injection amount of the fuel injection nozzle 7 are controlled by a signal from the control unit 10. The control unit 10 includes an accelerator opening sensor, an engine speed sensor, and the like, which are not shown, as well as cooling. Signals are input from the water temperature sensor 11 and the lubricating oil temperature sensor 12.

The coolant temperature sensor 11 is attached to the engine coolant outlet pipe 3 and detects the coolant temperature Tw. The lubricating oil temperature sensor 12 is attached to the engine main body 1 and detects the lubricating oil temperature Tr of the engine main body 1.

Next, the fuel injection control in this embodiment will be described. FIG. 3 is a flowchart showing the fuel injection control from engine start to warm-up.

In step 100, the cooling water temperature sensor 11
The lubricating oil temperature Tr is read from the lubricating oil temperature sensor 12 by reading the cooling water temperature Tw. At the start of the start, the read cooling water temperature Tw and the lubricating oil temperature Tr are stored and held as the starting water temperature Tw0 and the starting oil temperature Tr0, respectively.

At step 110, the table of FIG. 4 is referred to by the water temperature Tw, and the main injection timing advance amount ΔIT is set to be larger as the temperature becomes lower. This portion corresponds to the fuel injection timing advance amount setting means or the main injection timing advance amount setting means.

In step 120, the table of FIG. 5 is referred to by the oil temperature Tr, and the main injection amount increase basic value ΔQf0 is set to be larger at a lower temperature. This part corresponds to the fuel injection amount increase value setting means or the main injection amount increase value setting means.

In step 130, it is determined whether or not the current operation state satisfies the pilot injection permission condition based on information such as the accelerator opening, the engine speed, and the water temperature.
Only when the condition is the pilot injection permission condition, the next step 140 is executed.

In step 140, the table in FIG. 6 is referred to by the water temperature Tw, the pilot injection timing is set to the advanced side as the temperature is lower, and the table in FIG. , The pilot injection amount is set. This part corresponds to pilot injection control means.

In step 150, a basic water temperature Twb is calculated based on the oil temperature Tr. Basic water temperature T here
wb is a value corresponding to the cooling water temperature when the temperature of the cooling water in the regenerator has dropped to about the same level as the lubricating oil temperature.

More specifically, the basic water temperature increase ΔTw is obtained from the difference (Tr−Tr0) between the current oil temperature Tr and the oil temperature Tr0 at the time of engine start with reference to the table of FIG. The basic water temperature increase ΔTw is added to the water temperature Tw0 to obtain a basic water temperature Twb (= Tw0 + ΔTw).

In step 160, the basic water temperature T is calculated using the table of water temperature Tw-main injection timing advance amount ΔIT shown in FIG.
From w0, the basic advance amount ΔIT0 is obtained. Step 17
0, the difference between the water temperature Tw and the injection timing advance amount (the main injection timing advance amount ΔIT obtained from the actual water temperature Tw and the basic advance amount ΔIT obtained from the basic water temperature Tw0, using the map of FIG. 9).
A difference from 0) ΔIT−ΔIT0, a main injection amount increase correction coefficient α is obtained as a correction value for the main injection amount increase basic value ΔQf0. The main injection amount increase correction coefficient α is used for the purpose of reflecting a change in the fuel consumption rate due to the main injection timing advance amount.

In step 180, the water temperature Tw and the oil temperature Tr
It is determined whether or not the difference (Tw-Tr) is equal to or greater than a predetermined value T0. If the difference (Tw-Tr) is smaller than the predetermined value T0, the routine proceeds to step 190, where the main injection amount increase correction coefficient α Is set to 1. This is to prevent overcorrection when the temperature rise of the engine cooling water temperature is small, such as when the temperature of the cooling water inside the heat accumulator has dropped due to long-term storage or the like.

Finally, in step 200, the main injection amount increase value ΔQf is obtained by the product of the main injection amount increase basic value ΔQf0 and the main injection amount increase correction coefficient α (ΔQf = ΔQf0 ×
α). Here, the steps 150 to 200 correspond to the correction means.

The main injection timing advance amount ΔI obtained as described above
T is used in a form that is added to the requested main injection timing obtained from the accelerator opening, the engine speed, the atmospheric pressure, and the like. Similarly, the main injection amount increase value ΔQf is used in a form to be added to the required main injection amount (or the maximum main injection amount limit value) obtained from the accelerator opening, the engine speed, the atmospheric pressure, and the like. FIG.
Is repeatedly performed until the engine is stopped.

According to the above-described embodiment, the main injection timing (main injection timing advance amount), the pilot injection timing and the pilot injection amount are set according to the engine coolant temperature. Since the state can be appropriately controlled, it is possible to prevent misfire, generation of white smoke, and generation of a diesel knock sound due to an over-advance angle.

Further, in order to set the main injection amount (main injection amount increase value) based on the lubricating oil temperature, and to correct the increase value in anticipation of a change in fuel consumption rate due to the main injection timing advance, engine friction and combustion state are set. Therefore, the fuel injection amount can be set without excess or deficiency according to the above conditions, so that it is possible to suppress the deterioration of drivability and the generation of black smoke and white smoke.

As a means for promoting the temperature rise of the engine cooling water for the purpose of early warm-up, a combustion type or electric heater for heating the engine cooling water may be used.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a configuration diagram of a diesel engine showing one embodiment of the present invention.

FIG. 3 is a flowchart showing details of fuel injection control;

FIG. 4 is a schematic diagram of a table for setting a main injection timing advance amount;

FIG. 5 is a schematic diagram of a table for setting a basic injection amount increase basic value;

FIG. 6 is a schematic diagram of a table for setting a pilot injection timing.

FIG. 7 is a schematic diagram of a table for setting a pilot injection amount.

FIG. 8 is a schematic diagram of a table used for calculating a basic water temperature.

FIG. 9 is a schematic diagram of a map for setting a main injection amount increase correction coefficient.

[Explanation of symbols]

 Reference Signs List 1 engine main body 2 engine cooling water inlet pipe 3 engine cooling water outlet pipe 4 regenerator 5 regenerator cooling water introduction pipe 6 regenerator cooling water discharge pipe 7 fuel injection nozzle 8 common rail 9 supply pump 10 control unit 11 cooling water temperature sensor 12 lubrication Oil temperature sensor

Continued on the front page F term (reference) 3G301 HA02 JA00 JA22 JA23 JA24 KA01 KA05 MA11 MA18 MA23 NE01 NE11 PA09Z PE01Z PE08Z PF03Z

Claims (5)

[Claims] 1. A fuel injection timing advance amount setting means for setting a fuel injection timing advance amount in accordance with an engine cooling water temperature in a diesel engine having an engine cooling water temperature rise promotion means for early warm-up, Fuel injection amount increase value setting means for setting the fuel injection amount increase value in accordance with the oil temperature; and when the difference between the engine cooling water temperature and the engine lubricating oil temperature is a predetermined value or more, the fuel injection amount increase value And a correction means for setting a correction value for the fuel injection amount increase value to correct the fuel injection amount increase value. 2. A diesel engine having an engine cooling water temperature rise promoting means for early warm-up and performing a pilot injection prior to a main fuel injection, wherein a pilot injection timing and a pilot injection amount are determined in accordance with the engine cooling water temperature. Pilot injection control means for controlling, main injection timing advance quantity setting means for setting the main injection timing advance quantity according to the engine coolant temperature, and main injection for setting the main injection quantity increase value according to the engine lubricating oil temperature A control device for a diesel engine, comprising: an amount increase value setting unit; 3. When the difference between the engine cooling water temperature and the engine lubricating oil temperature is equal to or greater than a predetermined value, a correction value for the main injection amount increase value is set according to the main injection timing advance amount, and the main injection amount is increased. 3. The control device for a diesel engine according to claim 2, further comprising a correction unit configured to correct the injection amount increase value. 4. The engine cooling water temperature rise accelerating means introduces a part of high-temperature cooling water from the engine cooling system and stores it in a heat storage state, and supplies the stored cooling water to the engine cooling system when the engine is started. The control device for a diesel engine according to any one of claims 1 to 3, wherein the control device includes a heat accumulator that performs the heat storage. 5. The diesel engine according to claim 1, wherein the engine cooling water temperature rise promoting means includes a heater for heating the engine cooling water. Control device.