JPH03115729A - Operation control device for insulated engine - Google Patents

Abstract

PURPOSE:To lower the temperature in a cylinder lower than the combustible temperature so as to prevent the generation of knocking and the like by injecting water from a water injection nozzle into a combustion chamber of insulated structure in the last half of a compression stroke when engine speed and engine load are higher than the specified values. CONSTITUTION:The combustion chamber 1 of an engine is formed into insulated structure by a head liner 2 disposed in the hole part of a cylinder head 10 through an insulating gasket 4 and by the head part 9 of a piston 6 reciprocated in a cylinder liner 15. The head liner 2 facing the combustion chamber 1 is provided with a spark plug 3, a fuel injection nozzle 5 and a water injection nozzle 7. The nozzles 5, 7 are controlled by a controller 30 on the basis of various detection signals from various sensors 16, 26, 27, 29, 31 for detecting the operated state of the engine, and especially when engine speed and engine load are higher than the specified values, water is injected from the water injection nozzle 7 in the last half of a compression stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an operation control device for an adiabatic engine equipped with a nozzle for injecting water into a combustion chamber and a nozzle for injecting fuel.

[Conventional technology]

Traditionally, water-injected insulated ceramic diesel engines
For example, it is disclosed in Japanese Unexamined Patent Publication No. 184.923/1983. The water-injection type heat-insulating ceramic diesel engine disclosed in the publication has a combustion chamber having a heat-insulating structure formed by ceramic members of at least the portions of the cylinder head, cylinder liner, and piston head facing the combustion chamber, and is equipped with a water injection valve that receives high-pressure water from a water injection system independent of the fuel injection system and injects water into the combustion chamber, and controls the water injection timing and amount of water injected from the water injection valve. It is equipped with a water injection control device that increases the output of fuel light. This water injection type insulated ceramic diesel engine uses an insulated combustion chamber to increase the temperature of the combustion gas, injects an appropriate amount of water into the combustion chamber at the right time to vaporize the spray water, and uses the expansion power of this steam to increase the combustion gas. By adding to the expansion force, fuel consumption is reduced and output per unit fuel is increased, and the reduction in fresh air intake efficiency is compensated for by absorbing the heat of vaporization that accompanies the vaporization of water.

[Problem to be solved by the invention]

By the way, in the water injection type heat insulating ceramic diesel engine disclosed in the above-mentioned Japanese Patent Application Laid-open No. 60-184923, fuel is injected at the injection timing conventionally used for boat fishing, and the water injection is performed at the timing of the expansion stroke. It is carried out at the beginning, and water is evaporated and expanded, and the expansion force increases the output. Therefore, stoichiometric air-fuel mixture combustion cannot be performed, there is no effect of lowering the wall temperature, and the suction efficiency cannot be improved.

The purpose of this invention is to solve the above problems,
Immediately after the exhaust stroke of an adiabatic engine ends and the intake stroke begins, fuel is inhaled from the fuel injection nozzle at a relatively low pressure toward the piston head, the lower surface of the cylinder head, and the upper wall of the lychee, which are insulated and at a high temperature. The fuel is injected in an amount equivalent to the amount of air, and the fuel is vaporized by absorbing thermal energy from the wall surface, and in the latter half of the compression stroke, before the temperature inside the cylinder becomes higher than the flammable temperature of the fuel, the inside of the cylinder is heated. Water is injected from a water injection nozzle into the gas atmosphere to cool the inside of the cylinder, and the spark plug ignites the spark at the optimal timing near the end of the compression stroke to ensure ignition, thereby reducing the temperature inside the cylinder to the flammable temperature. An object of the present invention is to provide an operation control device for an adiabatic engine that cools the engine, prevents the occurrence of knocking, recovers thermal energy from the wall surface, and improves the suction efficiency by lowering the wall temperature.

(Means for Solving the Problems) In order to solve the above problems and achieve the above objects, the present invention is configured as follows.

That is, the present invention provides fuel injection means for injecting fuel into a combustion chamber having an adiabatic structure immediately after the start of an intake stroke, a water injection means for injecting water into the combustion chamber, a spark plug for igniting an air-fuel mixture, and an operating state of an engine. and a controller that controls the injection of water from the water injection means in the latter half of the compression stroke in response to the engine speed and load detected by the sensor being above a predetermined value. .

Further, in this adiabatic engine operation control device, in response to water injection into the combustion chamber, the spark plug is sparked near the end of the compression stroke to ignite the air-fuel mixture.

Furthermore, in this adiabatic engine operation control device, an air flow rate sensor for detecting an intake air amount is provided, and the controller injects a fuel flow rate equivalent to the air amount detected by the air flow rate sensor from the fuel injection means during the intake stroke. The injection is controlled immediately after the start.

[Effect]

The operation control device for an adiabatic engine according to the present invention is as follows.
It is structured as follows and operates as follows. That is,
This adiabatic engine operation control device injects water from the water injection means into the gas atmosphere in the combustion chamber during the latter half of the compression stroke in response to a high-speed, high-load signal exceeding a predetermined value detected by a sensor that detects the operating state of the engine. By injecting water from a water injection nozzle toward the target, the temperature inside the cylinder does not rise above the flammable temperature of the fuel, and the temperature inside the cylinder is cooled below the flammable temperature, preventing knocking and dissipating heat from the wall surface. It recovers energy and improves suction efficiency by lowering wall temperature.

In addition, in this adiabatic engine operation control device, the fuel injection means controls the injection of a fuel flow rate equivalent to the air amount detected immediately after the start of the intake stroke into the combustion chamber, so that the high temperature inside the cylinder is controlled. The theory is that the fuel can be injected from the fuel injection nozzle at a relatively low pressure toward the wall surface, and the fuel can be vaporized by absorbing thermal energy from the wall surface, increasing the vaporization time of the fuel. A mixing ratio can be generated.

Although the temperature inside the cylinder decreases due to the water injection, the spark plug ignites the air-fuel mixture near the end of the compression stroke, so the air-fuel mixture can be reliably ignited.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an operation control device for an adiabatic engine according to the present invention will be described in detail with reference to the drawings.

In FIG. 1, a schematic sectional view of an adiabatic engine incorporating an actuation control device according to the invention is shown. This adiabatic engine mainly consists of a cylinder block 11 equipped with a cylinder 14, a cylinder liner 15 fitted to the cylinder 14, a cylinder head 10 fixed to the cylinder block 11 via a gasket 28, and a cylinder head 10.
A headliner 2 has a heat-insulating structure in which the lower surface of the head and the upper part of the liner are integrally arranged in a hole formed in the hole via a heat-insulating gasket 4, and the piston head has a heat-insulating structure that reciprocates between the upper part of the liner and inside the cylinder liner 15. 9 and a combustion chamber formed by the piston head 9 and the headliner 2, in particular the headliner 2.
A spark plug 3, a fuel injection nozzle 5, and a water injection nozzle 7 are arranged in the fuel injection nozzle. The cylinder head 10 and the headliner 2 include an intake boat 12 and an exhaust boat 13.
An intake valve 8 is arranged on the intake boat 12, and an exhaust valve is arranged on the exhaust boat 13.

The headliner 2 and the piston head 9 are made of silicon nitride (S
iJt), is made of a ceramic material such as silicon carbide (SiC), aluminum titanate, potassium titanate, etc. to have a heat insulating structure. Further, in the adiabatic engine, the intake boat 12 is provided with a throttle valve 17 for adjusting the intake air flow rate and an air flow rate sensor 16 for detecting the intake air flow rate. The throttle valve 17 can adjust the intake air flow rate according to commands from the controller 30 and control the engine load. Furthermore, an exhaust gas treatment device 18 using an oxidation-reduction catalyst is provided in the exhaust pipe following the exhaust boat 13. Therefore, by burning the air-fuel mixture at a stoichiometric ratio and treating the generated exhaust gas with the exhaust gas treatment device 18, a low-pollution vehicle can be provided.

In this adiabatic engine, the spark plug 3 ignites the air-fuel mixture with a spark, the fuel injection nozzle 5 injects fuel supplied from the fuel injection pump 19 into the combustion chamber 1, and the water injection nozzle 7. is water injection pump 20
The water supplied from the combustion chamber is injected into the combustion chamber 1. Furthermore, the fuel injection pump 19 has a pump operating boo IJ21.
The water injection pump 20 is also provided with a pump operating pulley 22. These pump operating pulleys 21. ．． 22 is attached to the crankshaft 23 and is drivingly connected by a timing belt 25 to a crank pulley 24 that rotates together with the crankshaft 23. Therefore, as the engine is driven, the fuel injection pump 1
9 and the water injection pump 20 are driven by a timing belt 25.

At this time, the fuel injection pump 19 and the water injection pump 20
It is driven by a timing belt 25 so as to rotate synchronously at 1/2 the rotation speed of the crankshaft 23. Although not shown, the injection timing by the fuel injection pump 19 and the water injection pump 20 is not driven by the above-mentioned crank rotation, but is, for example, controlled by electrically opening and closing the fuel injection nozzle 5 and the water injection nozzle 7. It is also possible to provide a needle valve and to control the needle valve to open and close by commanding the controller 30.

In this adiabatic engine operation control device, as shown in FIG.
It is driven by an operating stroke consisting of four cycles: an expansion stroke C and an exhaust stroke.

In this operation control device, the fuel injection pump 19 injects fuel at a relatively low pressure toward the headliner 2 and the piston head 9, which have a heat-insulating structure and are heated to a high temperature, immediately after the exhaust stroke ends and the intake stroke starts. Injection timing is set in advance so that fuel is injected from the nozzle 5. By injecting fuel into the combustion chamber 1 immediately after the start of the intake stroke by operating the fuel injection pump 19, it is possible to increase the vaporization time of the fuel until ignition. Therefore, in response to a detection signal from the intake air flow rate sensor 16 inputted to the controller 30, the controller 30 controls the intake air flow rate by controlling the fuel supplied from the fuel injection pump 19 to the fuel injection nozzle 5 in accordance with the intake stroke A. It is possible to control injection of the fuel flow rate according to the amount until the stoichiometric mixture ratio is reached, and therefore ideal equivalent combustion can be performed. Further, a fuel injection port of the fuel injection pump 19 is provided with a flow rate adjustment valve that adjusts the flow rate of fuel supplied from the fuel injection pump 19 to the fuel injection nozzle 5 . Furthermore, the fuel used in this adiabatic engine is preferably a fuel with a high octane number, such as gasoline or alcohol.

If the octane number of the fuel is high, the compression ratio can be set high and cycle efficiency can be increased. Further, the water injection port of the water injection pump 20 is provided with a flow rate adjustment valve that adjusts the amount of water supplied from the water injection pump 20 to the water injection nozzle 7 .

In this adiabatic engine operation control device, an air flow rate sensor 16 detects the amount of intake air, and an intake air temperature sensor 29 detects the intake air temperature. Also,
A wall temperature sensor 31 provided in the headliner 2 detects the wall temperature of the combustion chamber 1.

Therefore, the detection values detected by each sensor are input to the controller 30, and the controller 30 receives each detection signal of intake air temperature, intake air amount, wall temperature, engine rotation speed, and engine load, and It is possible to calculate the temperature and pressure, determine whether self-ignition is possible, determine the amount of water to be injected into the combustion chamber 1, and control the amount of water to be injected from the water injection nozzle 7 to maintain it below the flammable temperature. .

In the operation control device for an adiabatic engine according to the present invention,
An example of the water injection operation will be described with reference to the processing flow diagram of FIG. 3. The adiabatic engine includes a rotation sensor 26 that detects the engine rotation, which is a sensor that detects the operating state of the engine, a load sensor 27 that detects the engine load, and an air flow sensor 16 that detects the amount of intake air. Each of these sensors 16, 26.2
The detection signal detected at 7 is input to the controller 30. The controller 30 has a sensor 16°26.21
, and controls the fuel injection flow rate supplied from the fuel injection pump 19 to the fuel injection nozzle 5 in response to each detection signal, and the fuel injection flow rate supplied from the water injection pump 20 to the water injection nozzle 7. Regarding the operation process of the adiabatic engine operation control device to control the water injection flow rate,
First, the engine rotation speed NE is detected by the rotation sensor 26, and the engine negative @L t is detected by the load sensor 27.
is detected (step 40). The detected engine rotational speed N and engine negative value hj L t are input to the controller 30 . The controller 30 receives a detection signal of the engine rotation speed N1 and sets the detected value to a preset engine rotation speed N. Compare and judge whether it is larger than (
Step 41). The rotation speed N is the set rotation speed N.

If it is larger, a detection signal of the engine load LE is received and a comparison is made to determine whether or not the detected value is larger than a preset engine load LED (step 42). load,
There is a load setting. If it is larger, the engine is operating at high speed and high load, and the combustion chamber 1 is at a considerably high temperature.
Since non-king may occur, the flow rate control valve of the water injection pump 20 is adjusted and opened according to the high speed and high load signal value, and the flow rate of water supplied from the water injection pump 20 to the water injection nozzle 7 is adjusted. water is injected into the combustion chamber 1 from the water injection nozzle 7 in the latter half of the compression stroke B (step 43).
). The water injection into the combustion chamber 1 lowers the cylinder hot water level (step 44), so the spark plug 3 is turned on (step 44).
Step 45), the air-fuel mixture is ignited by a spark near the end of the compression stroke (Step 46). Therefore, when the temperature of the combustion chamber 1 becomes high during high speed and high load, water is always injected to cool the combustion chamber 1 and lower the temperature, thereby preventing the occurrence of non-king.

Also, in step 41, the rotation speed N6 is changed to the set rotation speed N
,. If the load is not greater than the set load, and in step 42 the load is not greater than the set load. If the temperature inside the combustion chamber 1 is not higher than that, the temperature inside the combustion chamber 1 is not high and there is no need to inject water into the combustion chamber 1, so the water injection port of the water injection pump 20 is closed and the water injection nozzle 7 is closed. The water supply is cut off (step 47).

Therefore, the combustion chamber 1 can secure a temperature suitable for combustion, and the spark ignition of the spark plug 3 is not required, but the spark ignition of the spark plug 3 may be performed to ensure ignition. When the fuel is gasoline or alcohol, naturally the spark plug 3 is turned on to ignite the spark.

〔Effect of the invention〕

Since the operation control device for an adiabatic engine according to the present invention is configured as described above, it has the following effects.

That is, the operation control device for this adiabatic engine includes a fuel injection means for injecting fuel into a combustion chamber having an adiabatic structure immediately after the start of the intake stroke, a water injection means for injecting water into the combustion chamber, and a spark plug for igniting the air-fuel mixture. , a sensor that detects the operating state of the engine, and a controller that controls the injection of water from the water injection means in the latter half of the compression stroke in response to the engine speed and load detected by the sensor being above a predetermined value. In addition to being able to obtain high exhaust gas energy with an adiabatic engine, by injecting water from the water injection nozzle into the gas atmosphere inside the cylinder in the latter half of the compression stroke, the engine rotation and engine load increase, causing damage to the combustion chamber. Even if the fuel is about to reach a high temperature, water injection inside the combustion chamber cools the cylinder temperature below the flammable temperature, preventing the cylinder temperature from rising above the fuel combustible temperature, preventing knocking. , which recovers thermal energy from the wall surface and improves suction efficiency during the suction stroke by lowering the wall temperature.

Moreover, in this adiabatic engine operation control device, the fuel injection means injects the fuel into the combustion chamber immediately after the start of the intake stroke, so the fuel injection nozzle is directed toward the high-temperature wall inside the cylinder at a relatively low pressure. The fuel can be injected, the fuel can be vaporized by absorbing thermal energy from the wall surface, and the fuel vaporization time can be extended (can be set).
In conjunction with the intake stroke, injection control of the fuel flow rate according to the amount of intake air can be performed until the stoichiometric mixture ratio is reached, and equivalent combustion can be performed. Therefore, by arranging an exhaust gas treatment device using a redox catalyst in the exhaust pipe, exhaust gas treatment can be performed sufficiently and a low-pollution bundle can be provided.

Further, although the temperature inside the cylinder decreases due to water injection, the spark plug ignites the air-fuel mixture near the end of the compression stroke, so the air-fuel mixture can be reliably ignited.
There is no ignition error and the generation of unburned gas can be prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the operation control device for an adiabatic engine according to the present invention, and FIG. 2 is an explanatory diagram showing fuel injection timing and water injection timing in the operating side '4B device of the adiabatic engine of FIG. 1. , and FIG. 3 are process flow diagrams showing an example of the operation of the adiabatic engine operation control device of FIG. 1.

Claims (3)

[Claims] (1) A fuel injection device that injects fuel into a combustion chamber with an adiabatic structure immediately after the start of the intake stroke, a water injection device that injects water into the combustion chamber, a spark plug that ignites the air-fuel mixture, and detects the operating state of the engine. An operation control device for an adiabatic engine comprising a sensor, and a controller that controls the injection of water from the water injection means in the latter half of the compression stroke in response to engine speed and load detected by the sensor being above a predetermined value. (2) The operation control device for an adiabatic engine according to claim 1, wherein in response to water injection into the combustion chamber, the spark plug is sparked near the top dead center of the compression stroke to ignite the air-fuel mixture. (3) Install an air flow sensor to detect the amount of intake air,
2. The operation control device for an adiabatic engine according to claim 1, wherein the controller controls injection of a fuel flow rate equivalent to the air amount detected by the air flow rate sensor from the fuel injection means immediately after the start of an intake stroke.