JPS6155357A - White smoke emission preventing method at driving on highland by diesel engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of white smoke emission in time of driving on highland, by heatedly operating an intake heater, performing suction heating to improve a cold starting characteristic, even after completion of warming up at the time of driving on highland. CONSTITUTION:When a control unit for an intake heater discriminates cold starting time by a water temperature switch 43, with a key switch 41 turned on, it closes an electric switch 32, causing a heating element 13 of the intake heater 12 to be heated, thus suction heating takes place. And, starting is carried out by a starter switch 42, but when this starting fails to be done, the suction heating takes place again for the specified time long. And, in time of cold operation prior to warm-up completion, the electric switch 32 is closed, performing the suction heating, and further an atmospheric sensor 44 detects a hill, and if it judges that there is a driving range being liable to produce white smoke in particular, the suction heating continues even after the warm-up completion whereby white smoke emission is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for preventing white smoke from being emitted when a diesel engine used in a vehicle such as an automobile is running at high altitudes, and particularly relates to a method for preventing white smoke from being emitted when a diesel engine equipped with an intake heater is running at high altitudes. Relating to smoke emission prevention methods.

Conventional technology Generally speaking, diesel 8j! When driving at high altitudes, the atmospheric pressure decreases compared to when driving on flatlands, and the air ratio ff1ffl decreases, which worsens combustibility and makes white smoke more likely to occur.
It is known that This high altitude run? The emission of white smoke when driving at high altitudes becomes more noticeable when exhaust gas recirculation or fuel injection timing is retarded to reduce NOx in the exhaust gas, especially when driving at high altitudes. If exhaust gas recirculation or retardation of fuel injection II is performed during low-load operation, there is a risk of misfire occurring and the emission of white smoke may become intense.

Problems to be Solved by the Invention The present invention provides a diesel engine that does not emit white smoke even when exhaust gas recirculation or fuel injection timing is retarded to reduce NOx when driving at high altitudes. The purpose is to provide a method for preventing white smoke from being emitted when driving at high altitudes.

Means for Solving the Problems The method of preventing white smoke when a diesel engine runs at high altitudes according to the present invention utilizes an intake heater that heats the intake air to improve cold startability, so that warm-up is completed when running at high altitudes. Later +
It is characterized by heating the intake air by thermally operating the intake heater.

Effects and Effects of the Invention According to the method of the present invention, when driving at high altitudes, the intake heater continues to heat the intake air even after warming is completed, thereby improving the combustibility of the diesel engine and preventing the emission of white smoke.

Intake air heating during high-altitude driving is performed by the intake heater that is provided to improve cold starting performance, so there is no need to install a new intake heater to implement this method, and the method is conventionally known. The method of preventing white smoke emission when driving at high altitudes according to the present invention can be easily implemented by simply changing the control system of the intake heater for improving cold startability.

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

FIG. 1 shows one embodiment of a diesel engine in which the method for preventing white smoke emission when traveling at high altitudes according to the present invention is implemented.

In the figure, reference numeral 1 indicates an engine body, and the engine body receives a piston 3 in a cylinder bore 2. The piston 3 has a combustion chamber recess 4 at its top. Engine body 1
A fuel injection nozzle 5 is attached to the combustion chamber, and the fuel injection nozzle injects fuel toward the combustion chamber recess 4. The barrier body 1 is provided with an intake boat 7 that is opened and closed by an intake valve 6 and an exhaust boat 9 that is opened and closed by an exhaust valve 8.

An intake manifold 10 , an intake heater 12 , and an intake pipe 14 are connected in this order to the intake boat 7 , and the intake pipe 14 is connected to an intake outlet 17 of a turbocharger 15 . One exhaust manifold is connected in communication with the exhaust boat 9, and the exhaust manifold is also connected in communication with the exhaust gas inlet 18 of the turbocharger 1-15.

The intake heater 12 has a heat generating element 13 in the intake passage, and the heat generating element 13 generates heat e [by being selectively supplied with current from the battery power source 31 according to the opening and closing of the electric switch 32. It has become.

The intake manifold 10 is provided with a recirculation exhaust gas inlet 11, which inlet connects to the exhaust gas recirculation control valve 24.
, and is connected to an exhaust gas take-off boat 20 provided in the exhaust manifold 19 via an exhaust gas conduit 25.

The exhaust gas recirculation control valve 24 has a valve element 27 which is driven open and closed by a diaphragm device 26, and which resists the spring force of a helical compression spring 29 in response to an increase in the negative pressure supplied to the diaphragm chamber 28. The valve boat 30 can be heard by moving upward in the figure.

In the diaphragm chamber 28 of the diaphragm device 26, the negative pressure generated by the negative pressure pump 33 is applied to the constant pressure valve 34 and the water temperature control valve 3.
5 and a negative pressure control valve 36. The constant pressure valve 34 is a valve that adjusts the negative pressure generated by the negative pressure pump 33 to a predetermined level. The water temperature control valve 35 is sensitive to the cooling water temperature of the diesel engine, and when the cooling water temperature is below a predetermined value, it closes to cut off the supply of negative pressure to the negative pressure control valve 36, and the cooling water 7a degree When is not below a predetermined value, the valve is closed and negative pressure is supplied to the negative pressure control valve 36. The negative pressure control valve 36 is an electrically actuated negative pressure restriction valve that adjusts negative pressure according to an electric signal applied to the negative pressure control valve and supplies the negative pressure to the diaphragm chamber 28. It has become.

The negative pressure control valve 36 has an exhaust gas recirculation flow m valley control device 37.
The control device 37 receives information regarding the rotational speed of the diesel load from the engine rotational speed sensor 38 and the lever opening of the fuel injection pump of the diesel engine from the lever opening sensor 39. That is, each of them is given information regarding the engine load and outputs an electric signal to the negative pressure control valve 36 in accordance with EGR control characteristics determined in advance according to the engine speed and the lever opening degree.

As a result, negative pressure is supplied to the diaphragm chamber 28 with predetermined control characteristics depending on the engine speed and the pump lever opening degree, and this negative pressure causes the exhaust gas recirculation control valve 24 to
The D11 valve is controlled, and exhaust gas recirculation is performed at a flow rate according to a predetermined control characteristic.

The electric switch 32 is opened and closed by an intake heater control device 40.

The intake heater control 211 device 40 sends information from the key switch 41 regarding whether the engine key is inserted into the keyhole, and information from the starter switch 42 regarding whether the starter is operating, to the water quality sensor 4.
3, the information regarding the cooling water temperature is sent to the atmospheric pressure switch 44.
information on whether the atmospheric pressure is above a predetermined value,
The engine rotation speed sensor 38 provides information regarding the rotation speed of the diesel engine, and the lever opening sensor 39 provides information regarding the lever opening of the fuel injection pump. Based on these information, the electric power is controlled according to the flowchart shown in FIG. The opening and closing of the switch 32 is controlled (2111'').

The flowchart shown in FIG. 2 starts when the engine key is inserted into the key ball and the key switch 41 is turned on.

In the first step 1, it is determined whether the engine cooling water temperature TW detected by the water wetness sensor 43 is equal to or lower than a predetermined value Ta. When Tw<Ta, that is, at a cold start, proceed to step 2, whereas TW<7'a,
If not, proceed to step 6.

In step 2, closing the electrical switch 32 is initiated. When the electric switch 32 is closed, the battery power source 3 is supplied to the heat generating element 13 of the intake heater 12.
1, the heat generating element generates heat, and intake air is heated to improve cold startability. Also step 2
At this time, an indicator lamp 45 is turned on to indicate that the intake air is being heated to improve cold startability. After step 2, proceed to step 3.

In step 3, the energization time of the intake heater 12]-1 is determined in accordance with the cold water temperature rUTw at this time. This energization time TI is the cooling water temperature Tw
The lower the value, the longer the value may be set. After step 3, proceed to step 4.

In step 4, it is determined whether a predetermined time TI has elapsed since the electric switch 32 was closed, that is, after the intake heater 12 started being energized. If the predetermined time TI has not elapsed, this step 4
is repeatedly executed, and when the predetermined time T1 has elapsed, the process advances to step 5.

In step 5, listening to electrical switch 32 is performed. As a result, the heat generating element 1 of the intake heater 12
3 is stopped, and the indicator lamp 4 is turned off.
5 is turned off. This ends intake air heating for improving cold startability, so-called pre-intake heat. After step 5, proceed to step 6.

In step 6, it is determined from the on/off information of the starter switch 42 whether or not starting of the diesel engine by the starter has been completed. If the starting is not completed, this step 6 is repeatedly executed, and when the starting is completed, the process proceeds to step 7.

In step 7, it is determined whether the cooling water temperature detected by the water temperature sensor 43 is below a predetermined value Tb. When TW<Tb, that is, during cold operation before the completion of warm-up, the process proceeds to step 8, whereas when Tw<Tb, that is, after the completion of warm-up, the process proceeds to step 15.

In step 8, the electric switch 32 is closed again. As a result, the heat generating element 13 of the intake heater 12 is energized, the heat generating element operates to generate heat, and intake air is heated to improve cold operation performance. After step 8, proceed to step 9.

In step 9, the energization time T2 is determined according to the cooling water temperature Tw at this time.

This energization time T2 may be set longer as the cooling water temperature Tw is lower. After step 9, proceed to step 10.

In step 10, 'R%
A determination is made as to whether a predetermined time fill T2 has elapsed since the switch 8 was closed. When the predetermined time IaT2 has not elapsed, this step 10 is repeatedly executed, whereas when the predetermined time T2 has elapsed, step 1 is executed.
Go to 1.

In step 11, listening to the electrical switch 32 is performed. As a result, power supply to the heat generating element 13 of the intake heater 12 is stopped, and intake air heating for improving cold startability is completed. Step 11 is followed by step 12
Proceed to.

In step 12, it is determined whether the atmospheric pressure sensor 44 is in the on state. The atmospheric pressure switch 44 is
When the atmospheric pressure drops beyond a predetermined value, for example 625mmH9, the off state becomes the on state, and the atmospheric pressure drops to 760+
When the voltage rises above nmHo, the off state is switched to the on state. When the atmospheric pressure switch 44 is on, that is, when traveling at high altitudes, the process proceeds to step 13, whereas when the atmospheric pressure switch 44 is not on, the process returns to step 7.

In step 13, it is determined whether or not the intake heater is on during high-altitude driving. As shown in FIG. 3, for example, the intake heater ON region is determined according to the pump lever opening degree and the engine rotation speed, and the intake heater ON region is determined depending on the pump lever opening degree and the engine rotation speed. is a range where N+ is, for example, 1500 rpm or more and a predetermined value N2, for example, 350 Q rpm or less. This intake heater ON region is a driving region where white smoke is particularly likely to be generated when driving at high altitudes. Step 1
In step 3, if the operating range of the diesel engine is in the intake heater on range, the process advances to step 14, whereas if it is not in the intake heater on range, the process returns to step 7.

In step 14, electrical switch 32 is closed. As a result, the heat generating element 13 of the intake heater 12 is energized, and the heat generating element 13 heats the intake air to prevent white smoke from being emitted when driving at high altitudes. Also step 14
In this case, the flag F is converted to 1. After step 14, the process returns to step 7.

In step 15, it is determined whether flag F is 1 or not. [! l] At this time, it is determined whether or not the heat generating element 13 of the intake heater 12 is already energized. When F=1, that is, the heating element 13
If the heating element 13 is not energized, the process proceeds to step 12, whereas if the flag F=1 and the heat generating element 13 is energized, the process proceeds to step 16.

In step 16, it is determined whether the atmospheric pressure switch 44 is turned off. Atmospheric pressure switch 44
If the atmospheric pressure switch 44 is in the off state, the process proceeds to step 18, whereas if the atmospheric pressure switch 44 is not in the off state, that is, if it continues to be in the on state, the process proceeds to step 17.

In step 17, Diesel IXl! UI to determine whether or not the engine operating state is in the intake ON fA range.
J is performed. When the operating state is not the intake heater on MR, the process proceeds to step 18, whereas when the operating state is in the intake heater on region, the process returns to step 7.

In step 18, electrical switch 32 is opened. As a result, the power supply to the heat generating element 13 of the intake heater 12 is stopped, and intake air heating for preventing white smoke emission during high-altitude driving is completed. Further, in step 18, the flag F is converted to O. After step 18, proceed to step 7.

The opening and closing of the electric switch 32 is controlled according to the flowchart as described above, and the energization to the heat generating element 13 of the intake heater 12 is controlled accordingly, so that the heat generating element 1°3 of the intake heater 12 is activated during cold start. In addition to cold driving, when driving at high altitudes where white smoke is likely to be generated, the system operates to generate heat to heat the intake air to prevent white smoke from being emitted.

In the above embodiment, the power supplied to the heat generating element 13 of the intake heater 12 is not controlled, but the power supplied to the heat generating element 13 during high-altitude driving is based on the power consumption of the backup power supply 31. In order to reduce this, the value may be set to be smaller than that at the time of cold start.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram, not showing an example, of a diesel engine in which the method of preventing white smoke emission when running at high altitudes according to the present invention is implemented, and FIG. 2 is a method for preventing white smoke from a diesel engine when running at high altitudes according to the present invention. A flowchart showing an example of the implementation procedure,
FIG. 3 is a graph showing the intake heater ON region when driving at high altitudes. DESCRIPTION OF SYMBOLS 1... Engine body, 2... Cylinder bore, 3... Piston, 4... Combustion chamber recess, 5... Fuel injection nozzle, 6... Intake valve, 7... Intake port, 8 ...Exhaust valve, 9...Exhaust port, GOO...Intake manifold, 11...Recirculation exhaust gas inlet, 12...Intake heater, 13...Heating element, 14... intake pipe,
15...Turbocharger, 17...Intake ratio 0.1
8... Exhaust gas included 0.1... Exhaust manifold,
20... Exhaust gas extraction port, 24... Exhaust gas recirculation control valve, 25... Exhaust gas conduit, 26... Die A7 flam device, 27... Valve element. 28...Diaphragm to, 29...Compression coil spring. 30...Valve port, 31...Battery power supply, 32.
...Electric switch, 33...Negative pressure pump, 34...
Constant pressure valve. 35...Water temperature control valve, 36...Negative pressure control valve, 37.
... Exhaust gas recirculation flow ■Control device, 38... Engine speed sensor, 3... Lever opening sensor, 40... Control device for intake heater, 41... Key switch,
42... Starter switch, 43... Water temperature sensor,
44... Atmospheric pressure switch patent applicant: Toyota Motor Corporation representative
Attorney Patent Attorney Masaki Akashi No. 3 Figure Engine rotation speed (spontaneous) 1. Indication of incident Patent Application No. 176304 of 1982 2
, Title of the invention Method for preventing white smoke emissions from diesel engines when driving at high altitudes 3, Relationship with the case of the person making the amendment
20) I-Yota Jidosha Co., Ltd. 4, Agent Address: 3rd floor, Nagaoka Building, Kayaba-cho, 1-5-19 Shinkawa 1-chome, Chuo-ku, Tokyo, 104 Tel: 551-41716, Due to the invention increasing its power by amendment 07, Amendment Target of drawing 8, contents of amendment Figure 1 is amended as shown in the attached drawing. ,·" ,degree ·

Claims (1)

[Claims] A method for preventing white smoke emission from a diesel engine when running at high altitudes, characterized in that an intake heater that heats the intake air in order to improve cold startability is operated to generate heat even after warm-up is completed when running at high altitudes to heat the intake air.