JP3565089B2 - Internal combustion engine having a combustion heater - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an internal combustion engine having a combustion-type heater, and more particularly, to an internal combustion engine having a combustion-type heater that introduces combustion gas into an intake system of the internal combustion engine to promote warm-up of the internal combustion engine.
[0002]
[Prior art]
Internal combustion engines mounted on vehicles such as automobiles are designed to operate efficiently in a predetermined temperature range. This is because, for example, at low temperatures, engine fuels such as gasoline and light oil are difficult to vaporize, so that it is difficult to ignite these fuels, so that there is a problem that the startability is deteriorated.
[0003]
Further, as is well known, the interior of the vehicle is heated by using the heat generated when the internal combustion engine is operated. However, if the calorific value is insufficient, the interior of the vehicle cannot be sufficiently heated. In view of this, Japanese Patent Application Laid-Open No. 60-79149 discloses a technique in which a combustion heater is provided in an internal combustion engine for the purpose of promoting warm-up of the engine and improving the performance of a vehicle interior heating device, and utilizing heat of combustion gas emitted from the combustion heater. It is disclosed in the gazette.
[0004]
The technique disclosed in this publication introduces high-temperature combustion gas of a combustion-type heater into an intake passage of an internal combustion engine, thereby heating the engine intake air so that the engine can be easily started even when the internal combustion engine is in a low temperature state. It was made.
[0005]
However, the combustion gas emitted from the combustion heater is exhaust gas emitted by burning fuel. In the exhaust gas, the amount of oxygen contained therein is smaller than the amount of oxygen contained in the air before being subjected to combustion.
[0006]
Therefore, when the combustion gas is introduced into the intake passage as in the technique described in the above publication, when the amount of the combustion gas in the air flowing through the intake passage is increased by increasing the amount of the combustion gas, Although the engine warm-up is promoted by the heat of the combustion gas, the amount of oxygen in the air supplied to the cylinder is reduced. When the amount of oxygen is reduced, the amount of combustion in the cylinder is restricted, so that the startability of the internal combustion engine may be deteriorated. However, if the proportion of the combustion gas introduced into the intake passage is reduced in order to secure the required amount of oxygen, the engine warm-up will be insufficient this time and the startability will also deteriorate.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and introduces combustion gas generated by burning fuel into an internal combustion engine, and uses the heat contained in the combustion gas to adjust the temperature of intake air of the internal combustion engine. In an internal combustion engine having a combustion type heater, the minimum necessary temperature for starting the internal combustion engine is ensured, and the amount of oxygen occupied in the intake air of the engine is also sufficient, thereby improving the startability of the internal combustion engine. It is a technical object to provide an internal combustion engine having a combustion type heater.
[0008]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above-described problems.
(1) An internal combustion engine having a combustion type heater according to the present invention is attached to the internal combustion engine, and burns into the intake system of the internal combustion engine in accordance with the operation of engine start assisting means for assisting the start of the internal combustion engine until the internal combustion engine starts. An internal combustion engine having a combustion-type heater for introducing gas and increasing the temperature of intake air of the internal combustion engine by utilizing heat of the introduced combustion gas, wherein the internal combustion engine is started by the operation of the engine start auxiliary means. Before the internal combustion engine receives the heat of the combustion gas and reaches a predetermined temperature at which the internal combustion engine can be started, the oxygen amount increasing means for relatively increasing the oxygen amount in the intake system more than before.And starting supply of fuel to the internal combustion engine after the internal combustion engine reaches the predetermined temperature.
[0009]
Here, the "engine start assisting means attached to the internal combustion engine" is, for example, a starter motor, and the crankshaft of the internal combustion engine is rotated by the operation of the engine start assisting means. As a result, the piston moves in the cylinder. Start reciprocating.
[0010]
Further, "the internal combustion engine is started" means that in the internal combustion engine, the piston reciprocates in the cylinder without using the engine start assisting means attached to the internal combustion engine such as the starter motor. This means that the internal combustion engine operates itself.
[0011]
Further, "the engine has reached a predetermined temperature at which the internal combustion engine can be started" means a so-called engine temperature, i.e., the cylinder wall temperature or the engine coolant temperature is determined by the heat of the combustion gas or the frictional heat generated between the piston and the cylinder. Means that the temperature of the internal combustion engine increases to a temperature suitable for starting the internal combustion engine.
[0012]
A specific example of the case where the predetermined temperature is reached is as follows if the internal combustion engine is a self-ignition type internal combustion engine such as a diesel engine.
That is, the cylinder wall temperature increases due to the influence of the heat of the combustion gas and the frictional heat. Under the influence of the increased cylinder wall temperature, a portion corresponding to the vicinity of the end of the compression stroke of the internal combustion engine (hereinafter referred to as “compression”). There is a case where the cylinder wall temperature rises to such an extent that the intake air temperature at the end (hereinafter referred to as “compression end temperature”) reaches the target compression end temperature described below.
[0013]
The target compression end temperature is the lowest compression end temperature at which ignition and combustion in the combustion chamber can be ensured, that is, the minimum ignition temperature at which the diesel engine self-ignites.
If the compression end temperature reaches the target compression end temperature, at least the diesel engine will self-ignite, so that the temperature becomes suitable for starting the internal combustion engine.
[0014]
Therefore, if the compression end temperature does not reach the target compression end temperature, ignition becomes uncertain. In other words, if the temperature at the compression end reaches this target compression end temperature, the condition that the internal combustion engine can be started without using the engine start auxiliary means has been set, and thereafter, the heat generated by the internal combustion engine has A temperature equal to or higher than the target compression end temperature can be maintained.
[0015]
Furthermore, "increase the amount of oxygen in the intake system relatively than before" means that increasing the amount of oxygen itself or reducing the amount of oxygen in the intake air by reducing other components such as carbon dioxide. It does not matter whether or not the proportion of oxygen in the intake air is increased in a state where it does not change. However, in any case, it is assumed that a necessary amount is secured as an engine intake amount specific to the internal combustion engine.
[0016]
In the internal combustion engine having the combustion type heater according to the present invention, the combustion gas discharged from the combustion type heater before the internal combustion engine itself operates in accordance with the operation of the engine start assisting means attached to the internal combustion engine, that is, the intake system. To be introduced. Then, the temperature of the intake air of the internal combustion engine is increased by utilizing the heat of the combustion gas introduced into the intake system.
[0017]
At this time, the intake air that has been heated up containing the combustion gas enters the cylinder from its intake port as the piston reciprocates in the cylinder due to the rotation of the crankshaft by the engine start assisting means.
[0018]
Therefore, by introducing the intake gas containing the combustion gas into the cylinder, the cylinder can be warmed while the internal combustion engine is being assisted by the engine start assisting means, in other words, before the internal combustion engine itself operates. . Then, when the temperature of the cylinder gradually increases and eventually reaches a predetermined temperature at which the internal combustion engine can be started, the oxygen amount in the intake system is relatively increased by the oxygen amount increasing means.
Then, after reaching a predetermined temperature at which the internal combustion engine can be started, fuel supply to the internal combustion engine is started to start the internal combustion engine. That is, when the internal combustion engine is started, the internal combustion engine has reached the predetermined temperature, and the oxygen amount in the intake system has been increased.
[0019]
As described above, in the internal combustion engine having the combustion-type heater of the present invention, the internal combustion engine can secure the predetermined temperature required for the startup before the internal combustion engine is started and the oxygen amount occupied in the engine intake air can be ensured. Startability of the engine is improved.
Further, the supply of fuel to the internal combustion engine is started after the internal combustion engine has reached a predetermined temperature required for its start, in other words, the fuel supply to the internal combustion engine is not performed until the internal combustion engine reaches the predetermined temperature required for its start. Since the supply of water is not performed, the emission does not deteriorate.
[0020]
(2) In addition, it is preferable that the oxygen amount increasing means reduces or reduces the amount of the combustion gas introduced into the intake system to zero when the internal combustion engine reaches the predetermined temperature.
[0021]
In the internal combustion engine having the combustion heater according to the present invention, when the engine temperature reaches the predetermined temperature, the oxygen amount increasing means acts to reduce or reduce the amount of the combustion gas introduced into the intake system. Therefore, the ratio of the combustion gas to the intake air decreases. For this reason, the amount of the combustion gas occupying the intake air is reduced, so that the proportion of the fresh air occupying the intake air increases accordingly, and therefore the oxygen proportion occupying the intake air, that is, the oxygen amount increases.
[0022]
As described above, in the present invention, a sufficient amount of oxygen can be secured in a state where the engine temperature has reached the predetermined temperature, so that the startability of the internal combustion engine is enhanced.
(3) In addition, desirably, the oxygen amount increasing means is heater output control means for controlling the output of the combustion type heater.
[0023]
If the output of the combustion heater is reduced to zero, no combustion gas is emitted from the combustion heater, and if the output of the combustion heater is reduced, the amount of combustion gas discharged from the combustion heater also decreases. Therefore, the proportion of the combustion gas in the intake air decreases accordingly, and the oxygen amount increases. Therefore, the startability of the internal combustion engine can be improved as described above.
[0024]
(4) In addition, by introducing the combustion gas generated by performing the combustion of the fuel according to the combustion type heater in a lean state to the intake system, the oxygen amount in the intake system is relatively increased. It is preferable that
[0025]
Here, "performing the combustion of the fuel in the combustion type heater in a lean state" means to operate the combustion type heater with the air-fuel ratio in a lean state, that is, to burn the fuel.
[0026]
If the fuel is burned in a lean state, a small amount of fuel is burned with a large amount of air, so that the combustion gas discharged from the combustion heater also becomes a lean state. Therefore, if the lean combustion gas is included in the intake air, the amount of oxygen increases as compared with the case where the non-lean combustion gas is included in the intake air. Therefore, the startability of the internal combustion engine can be improved as described above.
[0027]
(5) In addition, when the engine temperature reaches the predetermined temperature, the oxygen amount increasing means switches the combustion gas that has been introduced into the intake system to the introduction into the exhaust system. Desirably.
[0028]
By the operation of the introduced gas switching means, the combustion gas that has been flowing in the intake system up to that time flows in the exhaust system. Therefore, the combustion gas does not flow into the intake system, and the proportion of fresh air in the intake air increases accordingly, so that the amount of oxygen increases. Therefore, the startability of the internal combustion engine can be improved as described above.
[0029]
(6) In addition, it is desirable to have a predetermined temperature achievement determining means for determining whether the engine temperature has reached the predetermined temperature.
The predetermined temperature achievement determination means directly detects the engine temperature with a temperature sensor, for example, and compares the detected value with the predetermined temperature to determine whether the engine temperature has reached the predetermined temperature. For example, an engine control device ( ECU) and the like.
[0030]
Since the predetermined temperature achievement determination means can reliably detect that the engine temperature has reached the predetermined temperature, the means for increasing the oxygen amount can be effectively used.
(7) In addition, the predetermined temperature attainment determining means may include an operating state of the internal combustion engine after introducing the combustion gas discharged from the combustion heater into the intake system of the internal combustion engine in accordance with the operation of the engine start assisting means. Satisfies a predetermined condition, it can be considered that the engine temperature has reached the predetermined temperature.
[0031]
(8) In addition, the predetermined condition is that a predetermined number of rotations of the internal combustion engine are performed by the attached engine start assisting means, a predetermined time elapses after the internal combustion engine starts rotating by the engine start assisting means, A predetermined amount of intake air may be introduced into a cylinder of the internal combustion engine after the rotation of the internal combustion engine is started by the engine start assisting means, or a combination thereof.
[0032]
Here, if the "predetermined number of rotations of the internal combustion engine", the "predetermined time after the start of rotation of the internal combustion engine", and the "predetermined amount relating to the intake" are satisfied, it is determined that the internal combustion engine has reached the predetermined temperature. Values that have a sufficient correlation.
[0033]
(9) In addition, after the start of the internal combustion engine, the increase in the amount of oxygen by the oxygen amount increasing means is stopped, and the combustion state in the operation state of the internal combustion engine before the combustion state of the combustion heater satisfies the predetermined condition. It is desirable to return to.
[0034]
Here, "returning the combustion state of the combustion heater to the combustion state in the operating state of the internal combustion engine before satisfying the predetermined condition" refers to the state before the output of the combustion heater is reduced to zero or reduced, for example, This is to bring the output to a high state, or to bring the fuel related to the combustion type heater into a state before performing the combustion in a lean state, for example, to a rich state.
[0035]
After the internal combustion engine has started, it means that the internal combustion engine is no longer operating with the engine start assisting means. In this case, the engine speed is reduced by the engine start assisting means. Significantly higher than the engine speed at the time of receiving the engine, and therefore the engine intake air amount is large. For this reason, it is not necessary to increase the oxygen amount in order to enhance the startability of the internal combustion engine, so that the increase in the oxygen amount by the oxygen amount increasing means is stopped. Also, by returning the combustion state of the combustion heater to the combustion state of the combustion heater in the operating state of the internal combustion engine before satisfying the predetermined condition, the combustion heater can discharge a large amount of combustion gas. Therefore, improvement in engine warm-up and improvement in performance of a heating device such as a heater for a vehicle compartment, which uses heat of combustion gas emitted from a combustion heater as a heat source, can be expected.
[0037]
(10)In addition, the introduction of the combustion gas into the internal combustion engine may be performed only when the internal combustion engine is in a predetermined operating state. Here, "when the internal combustion engine is in a predetermined operating state" means, for example, during operation of the internal combustion engine during cold operation at a temperature of about -10C to 15C or extremely cold operation at a temperature of -10C or lower. After the internal combustion engine is started, when the internal combustion engine itself generates a small amount of heat, for example, when the fuel consumption is small, and when the heat generation amount is small, the amount of heat received by the cooling water is small, or immediately after starting at room temperature higher than 15 ° C. For example, when the temperature of the cooling water is low, or when it is necessary to promote warm-up by the heat of the combustion gas discharged from the combustion heater.
[0038]
According to the present invention, the combustion gas is introduced into the internal combustion engine only when the internal combustion engine is in a predetermined operating condition. Therefore, for example, when the outside air temperature is high, the engine temperature becomes sufficient to start the internal combustion engine. In such a case, there is no need to operate the combustion heater unnecessarily. Therefore, the fuel for combustion of the combustion heater is not wastefully consumed.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of an internal combustion engine having a combustion heater according to the present invention will be described with reference to the accompanying drawings.
[0040]
FIG. 1 illustrates a diesel engine 1 (hereinafter, referred to as “engine 1”) as an internal combustion engine, and schematically shows an overall structure thereof.
The engine 1 includes an engine body 3 having a water jacket (not shown) containing engine cooling water, an intake device (intake system) 5 for feeding air necessary for combustion into a plurality of cylinders (not shown) of the engine body 3, An exhaust gas discharged from the cylinder after the air-fuel mixture formed by mixing the air sent to the cylinder through the device 5 with the engine fuel injected and supplied to the cylinder is burned in a combustion chamber formed at the top of the cylinder. An exhaust device (exhaust system) 7 for discharging into the atmosphere, and an EGR device as an exhaust recirculation device for suppressing the generation of nitrogen oxides by recirculating exhaust gas from the exhaust device 7 to the intake device 5 And a combustion gas generated at the time of burning the fuel separately from the engine 1 and a starter motor (not shown) serving as an engine start auxiliary means attached to the engine body 3. A combustion type heater that is introduced into the intake device 5 of the engine 1 in accordance with the operation of the engine and only when the engine 1 is in a predetermined operation state, and uses the heat of the introduced combustion gas to increase the temperature of the intake air. 9, a heater core 10 of a vehicle interior heating device for increasing the indoor temperature of a vehicle on which the engine 1 is mounted, and an ECU 11 as an engine control device for controlling the entire engine 1.
[0041]
Note that the case where the engine 1 is in a predetermined operating state means, for example, during operation of the internal combustion engine during cold operation at a temperature of about −10 ° C. to 15 ° C. or during extremely cold operation at a temperature of −10 ° C. or lower. After the engine is started, cooling is performed when the heat generation amount of the internal combustion engine itself is small, for example, when the fuel consumption is small, and when the heat generation amount is small, the heat receiving amount of the cooling water is small, or immediately after starting at room temperature higher than 15 ° C. This refers to a case where it is necessary to promote warm-up with the heat of the combustion gas discharged from the combustion type heater, such as when the water temperature is low.
[0042]
The engine body 3 converts a reciprocating motion of the piston in the cylinder into a rotational motion of the crankshaft via a connecting rod which is a connecting rod connecting the piston and the crankshaft. Further, the crankshaft is rotated by the starter motor before the start of the engine in which the crankshaft rotates. The rotation of the crankshaft translates to the operation of the engine 1.
[0043]
Further, fuel is injected and supplied to the combustion chamber by an injector (not shown) as fuel injection means. As described above, the fuel is discharged from the combustion heater 9 in accordance with the operation of the starter motor. After the combustion gas is introduced into the intake device 5, the supply of fuel to the combustion chamber by the injector is stopped until a predetermined condition described below is satisfied.
[0044]
The "predetermined condition" is, for example, a predetermined number of rotations of the crankshaft by the starter motor, a predetermined time after the start of rotation of the crankshaft by the starter motor, or a predetermined amount of intake air after the start of rotation of the crankshaft by the starter motor. Is introduced into the cylinder or a combination of these.
[0045]
In this embodiment, an example is described in which the predetermined condition is that the crankshaft is rotated by the starter motor a predetermined number of times, and the fuel injection is performed only after the crankshaft is rotated by the predetermined number by the starter motor.
[0046]
The intake device 5 has an intake passage 14 that starts with an air cleaner 13 that filters outside air and ends with an intake port (not shown) of the engine body 3.
In the intake passage 14, between the air cleaner 13 and the intake port, a compressor 15 a of the turbocharger 15, an intercooler 19 for cooling the intake air temperature which has been raised by the heat of compression generated when the compressor 15 a is operated, and a suction branch The intake manifold 22, which is a tube, and other intake system structures are sequentially arranged.
[0047]
An intake throttle valve 23 for controlling the amount of intake air flowing through the intake passage 14 is provided between the intercooler 19 and the intake manifold 22. Further, the combustion type heater 9 is mounted downstream of the intercooler 19 in the intake passage 14.
[0048]
The exhaust device 7 has an exhaust passage 27 starting at an exhaust port (not shown) of the engine body 3 and terminating at a muffler (not shown). In the exhaust passage 27, between the exhaust port and the muffler, exhaust system structures such as an exhaust manifold 28 as an exhaust branch pipe, a turbine 15b of the turbocharger 15, and a catalytic converter 29 as an exhaust gas purifier are arranged. I have.
[0049]
The EGR device 8 connects the intake passage 14 and the exhaust passage 27, bypasses the engine body 3, and returns the exhaust gas discharged from the exhaust port toward the intake side, and the exhaust gas flowing through the EGR passage 29. And an EGR valve 30 for controlling the amount.
[0050]
The combustion type heater 9 warms the engine cooling water with the combustion heat, and the warmed engine cooling water is sent to the heater core 10, the engine main body 3, etc., which needs to be heated, where necessary. Raise the temperature of the place where the temperature needs to be raised.
[0051]
The engine 1 is provided with a heat medium circulating passage W for feeding the engine cooling water heated by the combustion type heater 9 to the above-mentioned required temperature rising portion by an engine water pump (not shown). The heat medium circulation path W is heated by the cooling water introduction passage 31 that connects the engine body 3 and the combustion type heater 9 and guides the engine cooling water from the water jacket of the engine body 3 to the combustion type heater 9, and the combustion type heater 9. A cooling water discharge passage for returning the engine cooling water to the water jacket of the engine body after passing through the heater core;
[0052]
Further, an electric water pump 33 is provided in the cooling water introduction passage 31, and the operation of the electric water pump 33 promotes the circulation of the engine cooling water in the heat medium circulation path W. Alternatively, by circulating the engine cooling water by the electric water pump 33, the heater core 10 can be operated even when the engine is stopped.
[0053]
Here, the combustion type heater 9 will be described in detail with reference to FIGS.
The combustion type heater 9 has therein a heater internal cooling water passage 37 which communicates with the cooling water introduction passage 31 and the cooling water discharge passage 32 and is a part of the heat medium circulation passage W.
[0054]
The heater internal cooling water passage 37 has a cooling water introduction port 37a connected to the cooling water introduction path 31 and a cooling water discharge port 37b connected to the cooling water discharge path 32. The heater internal cooling water passage 37 is formed so as to circulate around the combustion chamber 39 of the combustion type heater 9.
[0055]
The combustion chamber 39 includes a combustion tube 40 as a combustion source that generates the flame F, and a partition wall 41 that covers the combustion tube 40 to prevent the flame F from leaking to the outside. The combustion chamber 39 is defined in the partition 41 by covering the combustion cylinder 40 with the partition 41. The partition 41 is also covered with the outer wall 42 of the combustion type heater 9.
[0056]
An annular gap is provided between the partition wall 41 and the outer wall 42, and this gap functions as the heater internal cooling water passage 37. The engine cooling water receives heat from the combustion chamber 39 while the engine cooling water flows in the heater internal cooling water passage 37. In other words, the engine cooling water exchanges heat with the hot combustion gas in the combustion chamber 39 to increase the temperature. Therefore, it can be said that the heater internal cooling water passage 37 is a heat exchange area.
[0057]
Further, the combustion chamber 39 has an air circulation port through which air enters and exits the combustion chamber 39. That is, the combustion chamber 39 has, as air circulation ports, an air supply port 62 for introducing combustion air into the combustion chamber 39 and combustion gas discharge ports 63 and 65 for discharging combustion gas from the combustion chamber 39.
[0058]
The air supply port 62 is located on the opposite side of the combustion chamber 39 from the side where the flame F exits from the combustion tube 40. Further, one combustion gas outlet 63 is provided at an appropriate position in the combustion chamber 39 corresponding to the downstream side of the cooling water passage 37 inside the heater, and the other combustion gas outlet 65 is provided with the flame F by the combustion cylinder 40. And is provided in communication with the partition wall 41 and the outer wall 42 so as to face the flame F.
[0059]
The combustion gas outlets 63 and 65 are connected via a connecting pipe 74 extending in parallel with the longitudinal direction of the combustion type heater 9. Each of the air supply port 62 and the combustion gas discharge ports 63 and 65 communicates with the intake passage 14. That is, the air supply port 62 communicates with the intake passage 14 via the air supply pipe 71 that supplies combustion air from the intake passage 14 to the combustion type heater 9. The combustion gas discharge port 63 communicates with the intake passage 14 via a connecting pipe 74 and a combustion gas discharge pipe 73 for discharging combustion gas from the combustion type heater 9 to the intake path 14. , Through a combustion gas discharge pipe 73.
[0060]
The connecting portion C1 of the air supply pipe 71 with the intake passage 14 and the connecting portion C2 of the combustion gas discharge pipe 73 with the intake passage 14 have the same diameter portion in the intake passage 14 so that no pressure difference occurs between them. That is, they are installed close to the same cross section. Further, the connection point C2 is downstream from the connection point C1. Furthermore, the connection points C1 and C2 are both located downstream of the intercooler 19, and the intake throttle valve 23 is located between the connection points C1 and C2. In this way, even if the combustion gas is introduced into the intake passage 14 through the combustion gas discharge pipe 73, heat damage to the intake throttle valve 23 due to heat of the combustion gas can be avoided.
[0061]
It is also conceivable to arrange the intake throttle valve 23 downstream of C2 in the intake passage 14.
The combustion gas discharge pipe 73 includes a valve device 78 that controls opening and closing of the combustion gas discharge port 65. The combustion gas discharge pipe 73 is connected to the combustion heater 9 via the valve device 78.
[0062]
The valve device 78 has a valve 80 for opening and closing the combustion gas outlet 65 and an actuator 82 for driving the valve 80. Depending on the degree of opening and closing of the valve 80, the proportion of the amount of combustion gas directly introduced from the combustion gas outlet 65 of the combustion type heater 9 to the combustion gas discharge pipe 73, that is, directly to the intake passage 14 is adjusted.
[0063]
That is, when the valve 80 is fully opened, most of the combustion gas flows through the combustion gas discharge port 65 to the combustion gas discharge pipe 73, and when fully closed, the combustion gas is discharged from the combustion gas discharge port 63 through the connection pipe 74. Almost all of the combustion gas flows to the combustion gas discharge pipe 73.
[0064]
When the valve 80 is half-opened, the ratio of the combustion gas flowing to the combustion gas discharge pipe 73 through the combustion gas discharge port 63 and the combustion gas discharge pipe 73 through the combustion gas discharge port 65 are determined according to the degree of opening. And the proportion of the combustion gas flowing through it.
[0065]
Adjustment of the proportion of the amount of the combustion gas discharged from the combustion gas discharge ports 63 and 65 into the intake passage 14 is made based on, for example, the outside air temperature or both the outside air temperature and the engine cooling water temperature. It has become so. The reason for making the determination based on the two temperatures is that when the temperature is low, both temperatures are often low. For example, when the engine 1 is just stopped, the engine cooling water temperature is low even if the outside air temperature is low. May be high.
[0066]
To illustrate the opening degree of the valve 80, for example, when the outside air temperature is low, the ratio of the combustion gas flowing to the combustion gas discharge port 65 becomes larger than the flow rate of the combustion gas discharge port 63 when the opening degree of the valve 80 is increased. To do.
[0067]
The outside air temperature is detected by a temperature sensor 13a provided immediately downstream of the air cleaner 13, and the engine cooling water temperature is detected by a temperature sensor 3a provided on the water jacket.
[0068]
The pipe 84 branches off from the combustion gas discharge pipe 73 at a position near the intake passage 14 in the combustion gas discharge pipe 73. Therefore, this pipe 84 is referred to as a branch pipe 84.
[0069]
The branch pipe 84 extends to the exhaust passage 27 so as to bypass the engine body 3, and is connected to the exhaust passage 27 at a location C <b> 3 of the exhaust passage 27 near the upstream side of the catalytic converter 29 installed in the exhaust passage 27. .
[0070]
At the intersection of the branch pipe 84 and the combustion gas discharge pipe 73, a three-way switching valve 86 is attached.
The three-way switching valve 86 is a valve that selects and switches whether the combustion gas passes through the combustion gas exhaust pipe 73 as it is toward the intake passage 14 or through the branch pipe 84. By operating the three-way switching valve 86, the flow direction of the combustion gas flowing into the three-way switching valve 86 is switched, and the combustion gas is introduced into the intake passage 14 or the exhaust passage 27.
[0071]
The case where the three-way switching valve 86 is switched to flow the combustion gas to the intake passage 14 is referred to as switching the three-way switching valve 86 to the intake side, and the case where the combustion gas flows to the exhaust passage 27 is exhausted. Switch to the side.
[0072]
When the three-way switching valve 86 is switched to the intake passage 14 side to flow the combustion gas into the intake passage 14, the combustion heater 9 and the intake passage 14 are substantially connected via the combustion gas discharge pipe 73. With this connection, combustion gas is introduced from the combustion heater 9 into the intake passage 14 of the engine 1.
[0073]
Further, when the three-way switching valve 86 is switched to the exhaust passage 27 side to flow the combustion gas to the exhaust passage 27, the combustion type heater 9 and the exhaust passage 27 are connected via a part of the combustion gas discharge pipe 73 and the branch pipe 84. Substantially connected. With this connection, the combustion gas is introduced from the combustion heater 9 into the exhaust system of the engine 1 and the combustion gas that has been introduced into the intake passage 14 is switched to be introduced into the exhaust passage 27. This can be referred to as introduced gas switching means.
[0074]
On the other hand, the combustion cylinder 40 has a wick (not shown) as a fuel evaporating section therein. Further, as shown in FIG. 1, a fuel introduction passage 88 for introducing fuel from the outside to the combustion cylinder 40 is connected. The fuel introduction passage 88 is connected to the fuel pump 89, and receives the pump pressure of the fuel pump 89 to discharge fuel from the fuel introduction passage 88 to the wick of the combustion cylinder 40, and as a result, the fuel evaporates. Further, the combustion cylinder 40 has a glow plug (not shown) that ignites the vaporized fuel evaporated by the wick.
[0075]
Further, the outer wall 42 of the combustion heater 9 is provided with a rotating fan (preferably a turbo-type rotating fan) 90 having a motor 92 as a drive source on the side of the combustion cylinder 40 opposite to the side where the flame F is emitted. An enclosed housing 93 is attached.
[0076]
The housing 93 has an air intake 95 for taking in air from outside, and the air supply pipe 71 is connected to the air intake 95. The housing 93 has an internal space S communicating with the air supply port 62. Therefore, the air supply port 62 is indirectly connected to the air supply pipe 71 via the internal space S.
[0077]
When the rotating fan 90 is rotated by the motor 92, air is introduced from the intake passage 14 into the housing 93 via the air supply pipe 71. The air guided to the housing 93 is supplied from the air supply port 62 to the combustion cylinder 40 as combustion air via the internal space S.
[0078]
The vaporized fuel evaporated by the wick by the combustion air is subjected to combustion to generate a flame F, and the combustion gas emitted from the flame F is then passed from the combustion heater 9 via the combustion gas discharge pipe 73, As described above, the three-way switching valve 86 is guided to the intake passage 14 or the exhaust passage 27 by switching.
[0079]
The amount of the guided combustion gas is determined by the magnitude of the output of the combustion type heater 9. For example, as the rotation speed of the rotating fan 90 increases, the amount of ventilation generated in the combustion gas discharge pipe 73 increases, and if the size and the momentum of the flame are the same, the amount of combustion increases in proportion to the rotation speed of the rotating fan 90. Gas is discharged from the combustion type heater 9. The rotation speed of the rotating fan 90 is determined by controlling the motor 92 by the ECU 11.
[0080]
Such a combustion type heater 9 operates as follows when it becomes necessary to raise the temperature of engine cooling water in order to promote warm-up of the engine body 3 and improve the performance of the heater core 10.
[0081]
First, as shown in FIG. 2, the operation of the valve device 78 causes the valve 80 to close, and as a result, the combustion gas outlet 65 closes. Further, as described above, a part of the intake air flowing through the intake passage 14 is introduced into the combustion cylinder 40 of the combustion type heater 9 through the air supply pipe 71 by the rotation of the rotary fan 90.
[0082]
Further, the fuel pump 89 sucks up fuel in a fuel tank (not shown) and discharges the fuel from the fuel introduction passage 88 to the wick of the combustion cylinder 40.
Further, while the engine is stopped, the electric water pump 33 is operated to pump the engine cooling water in the water jacket of the engine 1 into the cooling water passage 37 inside the heater of the combustion type heater 9.
[0083]
In addition, a mixture of intake air supplied to the combustion cylinder 40 by the rotary fan 90 and vaporized fuel supplied to the combustion cylinder 40 from the fuel introduction passage 88 and vaporized by the wick is formed by the glow plug. The fuel is ignited, a flame F is generated in the combustion tube 40, and the combustion starts.
[0084]
The high-temperature combustion gas generated by the combustion flows through the combustion chamber 39 toward the combustion gas outlet 63 by an airflow generated by the rotation of the rotary fan 90, and then connects to the combustion gas outlet 63. It is discharged to the pipe 74 (see the solid arrow a3 in FIG. 2).
[0085]
Then, the engine cooling water that has been pressure-fed from the water jacket to the heater internal cooling water passage 37 of the combustion type heater 9 via the cooling water introduction passage 31 by the electric water pump 33 passes through the heater internal cooling water passage 37 through the partition wall. Flowing around the entire outer surface of 41, it absorbs combustion heat and rises during that time. In other words, heat is exchanged in the entire area of the heater internal cooling water passage 37 in the heat exchange area.
[0086]
Then, the engine cooling water having absorbed the combustion heat is discharged from the heater internal cooling water passage 37 to the cooling water discharge passage 32 so as to flow to the heater core 10 (see broken arrows in FIGS. 2 and 3).
[0087]
Thereafter, the engine cooling water discharged from the combustion heater 9 returns to the water jacket of the engine body 3 via the cooling water discharge passage 32 to which the heater core 10 belongs.
[0088]
In the heater core 10, a part of the heat of the engine cooling water is exchanged with the heating air, and the temperature of the heating air rises. As a result, warm air is generated in the vehicle cabin.
In this way, the engine cooling water heated by the combustion heater 9 and heated to a high temperature flows to the water jacket of the engine body 3 and the heater core 10.
[0089]
Next, for example, when the engine 1 is in the above-mentioned predetermined operating condition and the temperature of the intake air of the engine 1 or the catalytic converter 29 needs to be raised at an early stage, for example, at the time of starting the engine, the combustion type heater 9 operates as follows. I do.
[0090]
As shown in FIG. 3, the valve 80 is opened by the operation of the valve device 78, and as a result, the combustion gas outlet 65 is opened. Subsequently, the rotating fan 90 is rotated by the motor 92 to supply a part of the intake air flowing through the intake passage 14 to the combustion cylinder 40 of the combustion heater 9. Further, the fuel pump 89 sucks up the fuel in the fuel tank and supplies the sucked up fuel to the wick of the combustion cylinder 40 from the fuel introduction passage 88.
[0091]
Then, a mixture of intake air supplied to the glow plug of the combustion cylinder 40 and supplied by the rotary fan 90 and vaporized fuel supplied to the combustion cylinder 40 from the fuel introduction passage 88 and vaporized by the wick is burned. It is burned in the cylinder 40.
[0092]
The high-temperature combustion gas generated by the combustion flows through the combustion chamber 39 toward the combustion gas discharge port 65 by blowing air generated by the rotation of the rotary fan 90, and then flows from the combustion gas discharge port 65 to the combustion gas discharge pipe 73. Is discharged to
[0093]
Similarly, depending on the degree of opening of the combustion gas discharge port 65, the combustion gas of the combustion gas before passing through the heater internal cooling water passage 37 or the combustion gas passing through a partial area of the heater internal cooling water passage 37. Are introduced into the intake passage 14 via the discharge to the combustion gas discharge pipe 73.
[0094]
Note that, of the combustion gas, the combustion gas before passing through the heater internal cooling water passage 37 is a combustion gas which does not exchange heat and goes to the combustion gas discharge port 65 with almost no contact with the inner surface of the partition wall 41 (for example, The combustion gas passing through a partial area of the cooling water passage 37 inside the heater is a combustion gas that exchanges a small amount of heat by being partially in contact with the inner surface of the partition wall 41 (see the arrow a1 in FIG. 3). (See, for example, arrow a2 in FIG. 3).
[0095]
Some of the combustion gas flows toward the combustion gas outlet 63 when the combustion gas outlet 65 is opened and is subjected to heat exchange (see arrow a3 in FIG. 3). It is less than the combustion gas flowing toward 65. This is for the following reason.
[0096]
That is, when the valve 80 of the valve device 78 is opened, the same or substantially the same pressure as the pressure P0 of the combustion gas at the combustion gas outlet 65 in the combustion chamber 39 is applied to the valve device 78. On the other hand, the pressure P1 of the combustion gas that has reached the starting end 74a of the connection pipe 74 via the combustion chamber 39 receives a pressure loss while passing through the combustion chamber 39, and is therefore smaller than the pressure P0. Therefore, it becomes difficult for the combustion gas that has reached the pressure P1 via the combustion chamber 39 to flow toward the intake passage 14 via the connection pipe 74. Therefore, the combustion gas having a pressure P0 higher than the pressure P1 is preferentially introduced into the intake passage 14 via the combustion gas discharge pipe 73.
[0097]
The high-temperature combustion gas discharged to the combustion gas discharge pipe 73 via the combustion gas discharge port 65 eventually reaches the three-way switching valve 86. Next, the combustion gas flows to a path that is not closed by the three-way switching valve 86. That is, the fuel gas passes through the combustion gas discharge pipe 73 as it is and exits to the intake passage 14 or flows to the branch pipe 84 and exits to the exhaust passage 27.
[0098]
Here, as described above, the combustion gas discharged from the combustion gas discharge port 65 does not exchange heat with the engine cooling water in the combustion heater 9 or even if heat exchange is performed. The exchange amount is small. For this reason, the combustion gas discharged from the combustion gas discharge port 65 has a considerably higher temperature than the combustion gas discharged from the combustion gas discharge port 63 and subjected to heat exchange with engine cooling water. Therefore, for convenience, the combustion gas that has undergone heat exchange with the engine cooling water by flowing toward the combustion gas outlet 63 is referred to as water-cooled combustion gas. The combustion gas that has not been replaced is called the combustion gas before water cooling.
[0099]
The pre-water-cooled combustion gas is supplied to the intake passage 14 or to a point C3 upstream of the catalytic converter 29 in the exhaust passage 27. Thus, the temperature of the intake air or the catalytic converter 29 can be raised early.
[0100]
FIG. 4 is a graph showing the temperature characteristics of the combustion gas before water cooling and the combustion gas after water cooling immediately after the combustion type heater 9 is ignited. The vertical axis indicates the temperature of the exhaust gas (gas temperature), and the horizontal axis indicates the elapsed time after the combustion type heater 9 is ignited. In the drawing, the broken line graph shows the temperature of the combustion gas before water cooling, and the solid line graph shows the temperature of the combustion gas after water cooling. Further, a line substantially at the center in the drawing and parallel to the horizontal axis is a reference temperature at which the engine 1 can be started at a low temperature, in other words, a line indicating a target compression end temperature as a low temperature start target value. In this embodiment, the target compression end temperature is set to about 320 ° C.
[0101]
It can be seen from FIG. 4 that the combustion gas before water cooling increases the cylinder wall temperature more rapidly than the combustion gas after water cooling, and thus the compression end temperature can be raised to the target compression end temperature at a stretch.
[0102]
Therefore, when the pre-water-cooled combustion gas is supplied to the cylinder, the compression end temperature rises at a stretch, and the vaporization of the fuel supplied to the cylinder is considerably promoted, so that the ignitability of the air-fuel mixture in the cylinder is improved. For example, the startability of the engine 1 can be improved.
[0103]
Now return to FIG.
The ECU 11 includes a central processing controller CPU, a read-only memory ROM, a random access memory RAM, an input interface circuit, an output interface circuit, and the like, which are interconnected by a bidirectional bus. Various sensors are connected to the input interface circuit via electric wiring regardless of the presence or absence of illustration. The output interface circuit includes an EGR valve 30, an electric water pump 33, a glow plug of a combustion cylinder 40, A valve device 78, a three-way switching valve 86, a fuel pump 89, a motor 92, and the like are connected via electric wiring.
[0104]
The sensors connected to the input interface circuit include, in addition to the temperature sensors 3a and 13a, an air flow meter (not shown) attached to the intake passage 14, a catalyst temperature sensor attached to the catalytic converter 29, an accelerator pedal or an accelerator pedal. An accelerator position sensor, an ignition switch, a starter switch, and the like attached to an accelerator lever or the like that operates in conjunction therewith can be exemplified. These sensors output an electrical signal corresponding to the detected value and send it to the ECU 11.
[0105]
The parameters of the temperature sensor and other various sensors are temporarily stored in the read-only memory ROM of the ECU 11, and are called up as needed.
In addition, when the compression end temperature is set to the target compression end temperature by the heat of the combustion gas discharged from the combustion type heater 9 before the engine 1 is started, the random access memory RAM stores the crankshaft by the starter motor. 5, which indicates a correlation between the target compression end temperature and the number of rotations of the crankshaft by the starter motor.
[0106]
The map M takes a predetermined number of rotations by a starter motor of a crankshaft necessary for the compression end temperature to reach the target compression end temperature on the vertical axis, and shows a horizontal axis before actuation of the starter motor. In other words, it is a predetermined rotation speed-engine cooling water temperature diagram obtained by taking the engine cooling water temperature before starting the engine 1.
[0107]
In FIG. 5, for example, when the engine cooling water temperature is a, it means that the compression end temperature reaches the target compression end temperature by rotating the crankshaft a 'by the starter motor.
[0108]
It can be seen from the map M that if the engine coolant temperature before the starter motor is operated is determined, the predetermined number of rotations of the crankshaft required to bring the compression end temperature to the target compression end temperature can be determined. . In other words, if the rotation speed of the crankshaft reaches the predetermined rotation speed obtained from the map M, it means that the compression end temperature has reached the target compression end temperature before the start of the engine 1.
[0109]
Further, it can be seen from the map M that when the engine coolant temperature is high, the predetermined number of rotations of the crankshaft by the starter motor may be small, and when it is low, it must be increased. The number of revolutions of the crankshaft means the amount of operating time of the combustion heater 9. When the number of revolutions of the crankshaft is large, the operation time of the combustion type heater 9 from the start of the starter motor is long, so that a large amount of combustion gas flows through the silidane. Therefore, even if the engine temperature is low, the compression end temperature reaches the target compression end temperature. Conversely, when the number of revolutions of the crankshaft is small, the operating time of the combustion type heater 9 from the start of the starter motor is short, so that a smaller amount of combustion gas flows into the cylinder. However, since the engine temperature is high, there is no problem that the compression end temperature reaches the target compression end temperature.
[0110]
The CPU of the ECU 11 operates according to each parameter of various sensors to control the combustion state of the combustion heater 17. In other words, the CPU controls the momentum, size, temperature, and the like of the flame of the combustion heater 17. Then, the temperature of the exhaust gas (combustion gas) of the combustion heater 17 is controlled by this control.
[0111]
The CPU determines the operating state of the engine 1 based on the output signal values of the various sensors described above. Then, control of the entire engine 1 such as fuel injection control is performed based on the determination result. At the same time, in order to control the output of the combustion type heater 9, the number of rotations of the rotary fan 90 is controlled as described above, and the amount of fuel supplied from the fuel introduction passage 88 is controlled. Further, it controls the operation of the valve device 78, the three-way switching valve 86, and the like.
[0112]
Next, a program for realizing an operation control execution routine of the engine 1 will be described with reference to a flowchart of FIG.
This program includes steps 101 to 109 described below. A program including these steps is stored in the ROM of the ECU 11. Further, the processing in each of the above steps is entirely performed by the CPU of the ECU 11. Note that the symbol S is used, and for example, if it is step 101, it is abbreviated as S101.
[0113]
In S101, it is determined whether an engine start control start condition is satisfied. The engine start control start condition means that a starter ON signal for operating the starter motor is output by turning on an ignition switch. When the determination is affirmative in S101, the process proceeds to the next S102, and when the determination is negative, the routine ends.
[0114]
In S102, the engine cooling water temperature before the starter motor is operated is read from the value detected by the temperature sensor 3a, and at the same time, the crankshaft necessary for setting the compression end temperature based on the engine cooling water temperature from the map M to the target compression end temperature. Is read, and the read value is stored in a read-only memory ROM.
[0115]
In S103, it is determined whether or not the engine 1 is currently in a warm-up request state. The warm-up required state is, for example, during the operation of the internal combustion engine in a cold state where the outside air is in a temperature range of about −10 ° C. to 15 ° C. or in an extremely cold state where the outside air is in a temperature range of about −10 ° C. or less, For example, after the internal combustion engine is started under the same conditions as above, there may be a case where the internal combustion engine is in a predetermined operating state.
[0116]
Therefore, the determination as to whether or not the engine is in the warm-up request state can be made, for example, based on whether or not the detection value of the temperature sensor 13a for detecting outside air is in the temperature range related to the warm-up request state. .
[0117]
When an affirmative determination is made in S103, the process proceeds to S104, and when a negative determination is made, the process proceeds to S109.
In S104, it is determined whether the combustion type heater 9 is in the OFF state. If an affirmative determination is made, the process proceeds to the next S105, and if a negative determination is made, the process proceeds to S107.
[0118]
In S105, it is determined whether or not the fuel is not injected from the injector into the cylinder and the starter motor is operating, that is, whether the starter ON control is to be executed. If an affirmative determination is made, the process proceeds to S106, and if a negative determination is made, this routine ends.
[0119]
In S106, the operation of the combustion type heater 17 is started, and the three-way switching valve 86 is controlled such that the combustion gas passes through the combustion gas discharge pipe 73 as it is and is discharged to the intake passage 14 which is the engine intake system. Note that S106 is a process immediately after proceeding in the case of an affirmative determination in S105, in other words, a process proceeding immediately after the operation of the starter motor is confirmed, so that the combustion gas discharged by the operation of the combustion heater 17 is Can be said to be discharged in accordance with the operation of the starter motor.
[0120]
Whether the combustion gas before water cooling flows into the intake passage 14 or the combustion gas after water cooling flows into the intake passage 14 by the operation of the valve device 78 depends on the situation where the engine 1 is placed, and a routine for selecting which is selected. Is omitted for simplicity. Since the present invention aims at improving the startability of the internal combustion engine, the case where the combustion gas flows through the intake passage has been described.
[0121]
In S107, it is determined whether or not the crankshaft rotated by the starter motor has reached a predetermined rotation speed based on the engine coolant temperature determined in S102 (whether or not the cranking rotation has passed a predetermined number of times), in other words, in S106. When the engine 1 receives the heat of the combustion gas discharged by the operation of the combustion type heater 9, it is determined whether or not the compression end temperature has reached a target compression end temperature which is a predetermined temperature. In other words, it is determined whether or not a predetermined number of revolutions corresponding to the engine cooling water temperature stored in the ROM has been reached, that is, whether a predetermined condition has been satisfied. If the determination is affirmative, it is considered that the compression end temperature has reached the target compression end temperature at that time, that is, the process proceeds to the next step S108 at that time, and if the determination is negative, this routine ends.
[0122]
Such S107 can be regarded as a predetermined temperature achievement determination means.
Further, the predetermined temperature achievement determination means rotates the crankshaft a predetermined number of times by the starter motor after introducing the combustion gas discharged from the combustion type heater 9 into the intake passage 14 of the engine 1 in accordance with the operation of the starter motor. In such a case, it is actually assumed that the compression end temperature has reached the target compression end temperature as described above. Therefore, the predetermined temperature achievement determination means can be rephrased as the predetermined temperature achievement deemed means.
[0123]
The predetermined temperature achievement determination means S107 is stored in the ROM of the ECU 11, and since the ROM belongs to the ECU 11, the ECU 11 is referred to as the predetermined temperature achievement determination means.
[0124]
In S108, for example, the output of the combustion heater 9 is set to zero or reduced (making the output zero or reducing is collectively referred to as combustion stop). Therefore, in this case, the amount of the combustion gas introduced into the cylinder becomes zero or becomes smaller than before, so that the fresh air amount increases accordingly. Therefore, the oxygen amount also increases in proportion to the increase in the fresh air amount. Therefore, when this S108 reaches a predetermined temperature at which the engine 1 can be started, the oxygen amount increasing means for increasing the oxygen amount in the intake passage 14 more than before is used. Since the output control of No. 9 is performed, it can be called a heater output control means.
Also, S108 is stored in the ROM of the ECU 11, and the ROM belongs to the ECU 11, so that the ECU 11 can be regarded as an oxygen amount increasing means (heater output control means).
[0125]
Further, when the fresh air amount increases as described above, the processing is performed assuming that the compression end temperature has already reached the target compression end temperature as described above, so that the temperature necessary for starting the engine 1 has already been secured. In this state, the amount of oxygen is surely increased.
[0126]
Then, instead of stopping the combustion of the combustion type heater 9, the combustion gas generated by performing the combustion of the fuel according to the combustion type heater in a lean state is introduced into the intake passage 14, so that the amount of oxygen in the intake passage 14 is reduced. You may make it increase relatively rather than before.
[0127]
In addition, instead of stopping the combustion of the combustion type heater 9, the operation destination of the combustion gas is switched by controlling the operation of the three-way switching valve 86, and the combustion gas that has been introduced into the intake passage 27 is branched via the branch pipe 84. Alternatively, the operation may be switched to the introduction to the exhaust passage 27. In this case, the operation of the three-way switching valve 86 causes the combustion gas that has been flowing in the intake passage 14 to flow into the exhaust passage 27 up to that point. Therefore, the combustion gas stops flowing through the intake passage 14, and the proportion of fresh air in the intake air increases accordingly, and as a result, the amount of oxygen increases. Therefore, the three-way switching valve 86 can be regarded as an oxygen amount increasing means.
[0128]
In S109, in addition to the fact that the oxygen amount required for starting the engine 1 in S108 has been secured, and since the compression end temperature has reached the target compression end temperature already described, fuel is injected into the cylinder by the injector. The engine 1 can be started. In other words, the supply of fuel to the engine 1 is stopped until the predetermined condition is satisfied.
[0129]
After the engine 1 is started, the increase in the oxygen amount by the oxygen amount increasing means is stopped, and the combustion state of the combustion type heater 9 is changed to the predetermined condition (for example, a case where the crankshaft is rotated a predetermined number of times by the starter motor). ) Is returned to the combustion state of the combustion type heater 9 in the operation state of the engine 1 before satisfying the condition (1). However, in this routine, the processing steps are omitted for the sake of simplicity.
[0130]
Note that "returning the combustion state of the combustion heater to the combustion state in the operating state of the internal combustion engine before satisfying the predetermined condition" means, for example, a state in which the 9 outputs of the combustion heater are zero or a high output before the output is reduced. Or to make the fuel related to the combustion type heater rich, for example, before performing the combustion in a lean state.
[0131]
Next, the operation and effect of this embodiment will be described.
In the engine 1, in accordance with the operation of the starter motor, in other words, before the engine 1 starts, the combustion gas discharged from the combustion type heater 9 is introduced into the intake passage 14 (see S106, S109). Then, the temperature of the intake air is increased by utilizing the heat of the introduced combustion gas.
[0132]
When the piston reciprocates in the cylinder due to the rotation of the crankshaft by the starter motor, the intake air, which has been heated by the reciprocating motion and contains the combustion gas, enters the cylinder through an intake port and the engine in the combustion chamber. After being subjected to combustion, it flows out of the cylinder via the exhaust port, that is, to the exhaust passage 27. At the same time, when the intake air that has been heated to include the combustion gas enters the cylinder, the cylinder wall temperature increases due to the heat of the combustion gas. That is, the cylinder is warmed before the engine 1 starts.
[0133]
When the compression end temperature reaches the target compression end temperature, which is a predetermined temperature required for the engine 1 to start after a while the temperature of the cylinder gradually increases, the combustion is controlled by the ECU 11 which is the oxygen amount increasing means. Since the operation of the type heater 9 is controlled and the combustion is stopped, the proportion of fresh air in the intake air flowing through the intake passage 14 increases accordingly, and the oxygen amount increases accordingly.
[0134]
As described above, in the engine 1 having the combustion heater according to the present invention, the target compression end temperature which is the minimum temperature required for starting the engine 1 is secured, and the oxygen amount occupying the engine intake is also secured. As a result, the startability of the engine 1 can be improved.
[0135]
Also, instead of stopping the combustion of the combustion type heater 9, the combustion gas generated by performing the combustion of the fuel in the combustion type heater 9 in a lean state is introduced into the intake passage 14, whereby the amount of oxygen in the intake passage 14 is reduced. Is relatively increased from before, it means that less fuel has been burned with more air, and the combustion gas discharged from the combustion heater 9 also becomes lean. Therefore, if the lean combustion gas is included in the intake air, the amount of oxygen increases as compared with the case where the non-lean combustion gas is included in the intake air. Therefore, the startability of the engine 1 can be improved as described above.
[0136]
In addition, when the three-way switching valve 86 is used as the oxygen amount increasing means, when the engine temperature reaches the target compression end temperature, the combustion gas that has been introduced into the intake passage 14 up to that time is sent to the exhaust passage 27. By switching to the introduction, the combustion gas stops flowing through the intake passage 14. Therefore, the proportion of fresh air in the intake air increases accordingly, and the amount of oxygen increases. Therefore, the startability of the engine 1 can be improved as described above.
[0137]
Further, in the engine 1, the ECU 11 as the predetermined temperature achievement determination means can reliably detect that the compression end temperature, which is the engine temperature, has reached the target compression end temperature, so that the oxygen amount can be effectively increased.
[0138]
In addition, after the engine 1 is started, the increase in the amount of oxygen by the ECU 11 as the oxygen amount increasing means is stopped, and the combustion state of the combustion type heater 9 is changed to, for example, the state of high output or rich combustion as described above. The state is returned to the combustion state. By doing so, combustion gas having a large amount of heat is discharged from the combustion type heater 9, so that improvement in engine warm-up and performance improvement of the heater core 10 and the like can be expected.
[0139]
In addition, the supply of the fuel to the engine 1 is stopped until the predetermined condition is satisfied. If the predetermined condition is satisfied, it is sufficient to consider that the compression end temperature of the engine 1 has reached the target compression end temperature, which is the predetermined temperature, but otherwise, the target compression end temperature has not been reached. Therefore, if fuel is supplied to the engine 1 in that state, the emission deteriorates. However, according to the present invention, if the compression end temperature is determined to have reached the target compression end temperature and the above-described predetermined condition that does not cause any problem is satisfied, the fuel is not supplied to the engine 1, so that the emission may deteriorate. Nor.
[0140]
Furthermore, even in the case of a diesel engine with a small intake amount and a small displacement, the intake air can be heated, and a glow plug (not shown), which is a heater provided in a cylinder head of the diesel engine for improving low temperature starting, can be eliminated. Become like If it is not necessary to provide the glow plug on the cylinder head, the mounting hole for mounting the glow plug on the cylinder head can be made unnecessary, so that the rigidity of the head is increased accordingly and the durability reliability of the cylinder head is improved.
[0141]
Also, after the engine is started, although the compression end temperature has reached the target compression end temperature, the engine cooling water temperature has not been sufficiently warmed, so that the heater core 10 serving as the vehicle interior heating device functions effectively. If it is not sufficient, it is preferable to operate the combustion heater 9 again even when the combustion heater 9 is stopped. The determination as to whether the engine has been started may be made based on those values indicated by the engine speed and the intake air amount when the engine is operating.
[0142]
Further, in S108, if the supply of the combustion fuel supplied to the combustion type heater 9 is temporarily stopped and the rotation fan 90 is continued to rotate, the combustion that has been warmed by the combustion of the combustion type heater 9 up to that time is performed. The air heated to a high temperature by receiving heat from the wall of the cylinder 40 or the partition wall 41 contains a sufficient amount of oxygen because it is not used for combustion by the combustion type heater 9 and therefore has a large amount of oxygen and is warm. Since the engine 1 is sent to the intake passage 14 in the state, the startability of the engine 1 can be further enhanced.
[0143]
【The invention's effect】
As described above, according to the internal combustion engine having the combustion-type heater of the present invention, the combustion gas generated by burning fuel is introduced into the internal combustion engine, and the heat generated in the combustion gas is used for the internal combustion engine. In an internal combustion engine having a combustion type heater that raises the temperature of the intake air of the internal combustion engine, the minimum amount of temperature required for starting the internal combustion engine is ensured, and the amount of oxygen occupying the engine intake air is also made sufficient. Startability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an internal combustion engine having a combustion heater according to the present invention.
FIG. 2 is a cross-sectional view showing an operation state of a combustion heater.
FIG. 3 is a sectional view showing another operation state of the combustion heater.
FIG. 4 shows an exhaust gas temperature characteristic of a combustion type heater immediately after ignition and a combustion gas before water cooling and a combustion after water cooling.
Graph diagram showing comparison with gas
FIG. 5 is a diagram showing a predetermined rotation speed-engine cooling water temperature diagram.
FIG. 6 is a flowchart showing an engine operation control execution routine;
[Explanation of symbols]
1. Diesel engine (internal combustion engine)
3. Engine body
3a: Temperature sensor
5. Intake device
7 Exhaust device
8 EGR device
9. Combustion heater
10 ... heater core
11 ECU (oxygen amount increasing means, heater output control means, predetermined temperature achievement determining means) 13 air cleaner
13a: Temperature sensor
14. Intake passage (intake system)
15 ... Turbocharger
15a ... Compressor
15b ... turbine
19. Intercooler
22 ... intake manifold
23 ... intake throttle valve
27 ... Exhaust passage (exhaust system)
28… Exhaust manifold
29: Catalytic converter
30 ... EGR valve
31 ... Cooling water introduction passage
32 Cooling water discharge path
33 ... Electric water pump
37: Cooling water inside the heater
37a: Cooling water inlet
37b: Cooling water outlet
39 ... Combustion chamber
40 ... combustion cylinder
41 ... partition wall
42 ... Outer wall
62 ... Air supply port
63… combustion gas outlet
65: Combustion gas outlet
71 ... Air supply pipe
73 ... combustion gas exhaust pipe
74 ... connecting pipe
74a: Start end of connecting pipe 74
78 ... Valve device
80 ... Valve
82 ... actuator
84 ... Branch pipe
86 ... three-way switching valve (introduced gas switching means)
88: fuel introduction passage
89 ... Fuel pump
90 ... Rotating fan
92 ... Motor
93 ... Housing
95 ... Air intake
C1: connection point between the air supply pipe 71 and the intake passage 14
C2: connection point between the combustion gas exhaust pipe 73 and the intake passage 14
C3: A location near the upstream side of the catalytic converter 29
F ... Flame
M… Map
P1: pressure of the combustion gas after water cooling at the starting end 74a of the connecting pipe 74
P0: pressure of the combustion gas before water cooling at the combustion gas outlet 65
S: Internal space of housing 93
W: Heat medium circulation path
a1 ... Combustion gas before passing through the heat exchange area
a2: Combustion gas passing through part of the heat exchange area
a3: Combustion gas passing through most of the heat exchange area

Claims (10)

Combustion gas is introduced into the intake system of the internal combustion engine in accordance with the operation of the engine start assisting means attached to the internal combustion engine and assisting the start of the internal combustion engine until the internal combustion engine is started, and the heat of the introduced combustion gas is used. An internal combustion engine having a combustion heater that increases the temperature of the intake air of the internal combustion engine,
Before the internal combustion engine is started by the operation of the engine start assisting means, when the internal combustion engine receives a heat of the combustion gas to reach a predetermined temperature at which the internal combustion engine can be started, the oxygen amount in the intake system is changed. an oxygen amount increasing means for relatively increased than before,
An internal combustion engine having a combustion heater, wherein the supply of fuel to the internal combustion engine is started after the internal combustion engine reaches the predetermined temperature . 2. The oxygen amount increasing means according to claim 1, wherein the amount of the combustion gas introduced into the intake system is reduced to zero or reduced when the internal combustion engine reaches the predetermined temperature. An internal combustion engine having a combustion heater. The internal combustion engine having a combustion type heater according to claim 2, wherein the oxygen amount increasing means is a heater output control means for controlling an output of the combustion type heater. By introducing combustion gas generated by performing combustion of the fuel according to the combustion type heater in a lean state into the intake system, the amount of oxygen in the intake system is relatively increased. An internal combustion engine having the combustion heater according to claim 3. When the engine temperature reaches the predetermined temperature, the oxygen amount increasing means is an introduced gas switching means for switching the combustion gas introduced into the intake system to the introduction into the exhaust system. An internal combustion engine having the combustion heater according to claim 2. The internal combustion engine having a combustion type heater according to any one of claims 1 to 5, further comprising predetermined temperature achievement determination means for determining whether or not the engine temperature has reached the predetermined temperature. The predetermined temperature attainment determination means is configured such that, after introducing the combustion gas discharged from the combustion type heater into the intake system of the internal combustion engine in accordance with the operation of the engine start assisting means, the operating state of the internal combustion engine satisfies predetermined conditions 7. The internal combustion engine having a combustion heater according to claim 6, wherein in such a case, the engine temperature is considered to have reached the predetermined temperature. The predetermined condition is that a predetermined number of rotations of the internal combustion engine are performed by the attached engine start assisting means, a predetermined time elapses after rotation of the internal combustion engine is started by the engine start assisting means, 8. An internal combustion engine having a combustion type heater according to claim 7, wherein a predetermined amount of intake air is introduced into a cylinder of the internal combustion engine after the start of rotation, or a combination thereof. After starting the internal combustion engine, increasing the oxygen amount by the oxygen amount increasing means is stopped, and the combustion state of the combustion heater is returned to the combustion state in the operation state of the internal combustion engine before the predetermined condition is satisfied. An internal combustion engine having the combustion heater according to claim 7. 10. The internal combustion engine having a combustion-type heater according to claim 1, wherein the introduction of the combustion gas to the internal combustion engine is performed only when the internal combustion engine is in a predetermined operating state.

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