JPH11182393A - Rapid warming up device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate friction loss and worsening of exhaust air composition rapidly by heating the vicinity of a cylinder locally at the time of cold start. SOLUTION: A heat storage material storage chamber 12 is formed in a cylinder block 11 so as to surround a cylinder, and a latent heat type heat storage material 13 composed of sodium acetate trihydrate is filled therein. The heat storage material 13 receives heat directly from the cylinder and becomes a liquid phase to store latent heat. At the time of cold start, a shock is given to the heat storage material 13 cooled excessively by the voltage application of an electrode 15 to start the change of phase and generate latent heat. A temperature of the heat storage material 13 is detected by a temperature sensor 14 to judge whether heat radiation is possible or not based on the history of temperatures. A voltage is applied only when heat radiation is possible and an engine temperature at the time of its start is low. A cylinder head 18 having high heat load has a water jacket 19 and is cooled by the forced circulation of cooling water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid warm-up device for rapidly increasing the temperature particularly near a cylinder when an internal combustion engine is started.

[0002]

2. Description of the Related Art At the start of an internal combustion engine, various parts of the internal combustion engine,
In particular, when the cylinder wall temperature or the combustion chamber temperature is low, friction loss with respect to the movement of the piston increases, and the exhaust gas composition deteriorates.

For this reason, a heat storage type rapid warm-up device has been proposed in which heat is stored during operation of an internal combustion engine using a heat storage material, and the heat is released at the next start to promote warm-up of the internal combustion engine. ing. For example, JP-A-6-173679 discloses that a latent heat type heat storage material is disposed in a cooling water passage between a radiator and an internal combustion engine, and the heat of the cooling water is used as latent heat while the internal combustion engine is being heated. A device is disclosed which stores and restarts the stored heat to the cooling water of the internal combustion engine at the time of storage and restart.

[0004]

However, in this conventional apparatus, the heat storage material is provided outside the internal combustion engine, and both the heat storage from the internal combustion engine and the supply of heat to the internal combustion engine are not performed. Since the cooling is performed via cooling water, the efficiency is low.Especially, even after the heat is released from the heat storage material after the engine starts, there is a time delay until the temperature of the cylinder of the internal combustion engine actually rises. There is a problem that accompanies. In addition, at the time of startup, the heat radiated from the heat storage material is dispersed to various parts of the engine, so that the vicinity of the cylinder cannot be intensively heated. Therefore, it is not possible to sufficiently avoid the deterioration of the exhaust gas composition and the deterioration of the fuel efficiency immediately after the start.

[0005] Such a problem at the time of starting is, of course, a problem even in a normal internal combustion engine for a vehicle. In particular, when an electric motor is provided together with the internal combustion engine as a driving source of the vehicle, the operating conditions of the vehicle are reduced. In a hybrid vehicle in which the stop and restart of the internal combustion engine are automatically performed based on the above, the problem becomes even greater. That is, since the stop and restart of the internal combustion engine are frequently repeated, the exhaust performance at the time of starting and the like become a problem, and more efficient heat storage and heat radiation are required.

[0006]

A rapid warm-up device for an internal combustion engine according to the present invention accommodates a latent heat type heat storage material inside the internal combustion engine and promotes a phase change of the heat storage material in a supercooled state. The electrode is arranged in the heat storage material, and a voltage is applied at the time of starting the internal combustion engine to radiate heat.

The rapid warm-up device of the present invention comprises an electric motor for applying a driving force to the vehicle together with the internal combustion engine, and the internal combustion engine is stopped and restarted based on the vehicle operating conditions. It is suitable for an internal combustion engine of a hybrid vehicle.

The above-mentioned latent heat type heat storage material is heated during the operation of the internal combustion engine after the completion of warm-up, and stores heat as latent heat. When the temperature of the internal combustion engine is reduced after the internal combustion engine is stopped, the temperature of the heat storage material is also reduced. Then, at the time of restart, a voltage is applied to the electrodes arranged in the heat storage material. The electric shock breaks the supercooled state, the heat storage material changes its phase to a solid phase, and the stored heat is radiated to directly heat the internal combustion engine.

According to a second aspect of the present invention, the heat storage material is disposed around the cylinder of the cylinder block, and the heat absorption of the heat storage material cools the cylinder block side, and the cylinder head is cooled. The side is cooled by forced circulation of cooling water.

Therefore, the heat generated in the cylinder of the internal combustion engine is efficiently given to the heat storage material.
The cylinder is heated locally and efficiently by the heat provided by the heat storage material, and the cylinder wall temperature rises quickly.
As a result, friction loss and deterioration of the exhaust gas composition can be quickly avoided. Then, the cylinder head side is reliably cooled by forced circulation of cooling water, similarly to a general water-cooled cooling device.

The invention according to claim 3 further includes means for detecting a temperature state of the internal combustion engine, and applies a voltage to release heat only when the internal combustion engine is in a predetermined low temperature state at the time of starting.

As the temperature of the internal combustion engine, for example, a cooling water temperature, a lubricating oil temperature, etc. are used. Not done. Note that the temperature condition at this time needs to be a temperature at which the heat storage material is in a supercooled state.

Further, the invention according to claim 4 further comprises means for determining whether or not latent heat is stored in the heat storage material based on the temperature history after heat release. It is characterized in that heat is released only by applying a voltage.

As the temperature history after heat release, for example, the sum of the time during which the heat storage material temperature reaches the melting point during operation, or the sum of the product of the temperature and the time at or above the melting point,
The amount of heat received by the heat storage material can be roughly estimated, and based on this,
It can be determined whether or not heat is stored as latent heat in the heat storage material. If the heat storage material does not return to the heat storage state again after the heat has been radiated once, since the heat can not be substantially radiated, no voltage is applied.

[0015] As the heat storage material,
Sodium acetate trihydrate is preferred. This sodium acetate trihydrate has a melting point (58 ° C.) lower than the cooling water temperature after warming up, and is supercooled to about −20 ° C. to −30 ° C. lower than the general outside temperature. Is held.

[0016]

According to the rapid warm-up device for an internal combustion engine according to the present invention, since the latent heat type heat storage material is housed inside the engine, the heat generated in the engine can be efficiently stored,
At the time of starting, the engine can be directly heated by the heat released from the heat storage material, and deterioration in fuel efficiency and deterioration in exhaust gas composition immediately after starting can be quickly eliminated.

In particular, by using the present invention for an internal combustion engine of a hybrid vehicle, it is possible to effectively suppress the emission of harmful exhaust gases due to frequent restarts.

According to the second aspect of the present invention, the vicinity of the cylinder is locally heated by the heat storage material,
The temperature can be more efficiently raised, and the cylinder head side can be reliably cooled.

According to the third or fourth aspect of the present invention, unnecessary voltage application and heat radiation can be avoided, and energy can be used more effectively.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the rapid warm-up device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a configuration of a drive system of a hybrid vehicle using an internal combustion engine 1 provided with a rapid warm-up device according to the present invention. The drive system is connected to a crankshaft of the internal combustion engine 1 via a clutch device 2. The motor 3 is further connected to the input shaft of the continuously variable transmission 4 and drives the axle 5. The electric motor 3 is a so-called motor generator and has a power generation function of generating power when driven. In the hybrid vehicle of this embodiment, as shown in FIG.
The internal combustion engine 1 is driven only when it is higher, and the vehicle is driven by the electric motor 3 in a low vehicle speed range equal to or lower than V1. That is, in the region below V1, the clutch device 2 is in a disconnected state and the internal combustion engine 1 is kept in a stopped state. When the vehicle speed reaches V1 during acceleration, the clutch device 2 is connected and immediately The engine 1 is started. Therefore, the internal combustion engine 1
Stop and start are repeated.

FIG. 3 shows a configuration of a rapid warm-up device for the internal combustion engine 1. A heat storage material accommodating chamber 12 is formed in a cylinder block 11 so as to surround the cylinder.
For example, sodium acetate trihydrate (CH ₃ COONa
3 (H ₂ O)). This sodium acetate trihydrate has a melting point (58
℃) does not cause a phase change from the liquid phase to the solid phase even when cooled to a temperature below the melting point.
It has the property of being in a supercooled state while storing latent heat up to about minus 30 ° C. In the heat storage material storage room 12,
A temperature sensor 14 for detecting the temperature of the heat storage material 13 is provided, and a pair of electrodes 15 for applying an electric shock to the heat storage material 13 are provided. When a voltage is applied to the electrode 15 when the temperature of the internal combustion engine 1 is lowered and the heat storage material 13 is in a supercooled state, the impact causes a phase change of the heat storage material 13 to a solid phase, thereby promptly causing latent heat. Is released. The timing of applying a voltage to the electrode 15 is controlled by a control unit 16 as described later.

In this embodiment, the heat storage material storage chamber 12 surrounds a portion other than the upper end of the cylinder, and a water jacket 17 is formed above the cylinder block 11 so as to surround the upper end of the cylinder. I have. That is, cooling water (water jacket) is not interposed between the cylinder and the heat storage material 13, and heat is directly transferred. In addition, a water jacket 19 similar to a general water-cooled cooling device is formed in the cylinder head 18. Cooling water is forcibly circulated through the water jackets 17 and 19 by a water pump 20 to cool the upper end of the cylinder having a high heat load and the vicinity of the combustion chamber. In addition, 21 is a radiator, 22 is a bypass passage, 23 is a thermostat valve for switching the flow path between the radiator 21 and the bypass passage 22 according to the temperature of the cooling water, and 24 is a heater core for heating the passenger compartment. .

The control unit 16 receives a vehicle speed signal, an accelerator opening signal, and the like indicating the driving state of the vehicle, and controls the stop and start of the internal combustion engine 1 based on these, as described above. An engine temperature signal indicating a warm-up state, that is, a temperature state of the internal combustion engine 1 and a heat storage material temperature signal from the temperature sensor 14 are input, and voltage application to the electrode 15 is controlled based on these. The temperature signal of the engine may be a lubricating oil temperature, a cooling water temperature, a catalyst temperature, or the like.

FIG. 4 is a flowchart showing the flow of processing executed when the control unit 16 determines that the internal combustion engine 1 needs to be started with a rise in vehicle speed from a running state using only the electric motor 3. As shown
When the control unit 16 determines that the internal combustion engine 1 needs to be started, the process proceeds to step 1, where the internal combustion engine 1 is started. That is, fuel injection, ignition control, and the like are started. Then, the process proceeds to step 2, and it is determined whether or not the latent heat is stored in the heat storage material 13 based on the temperature history after heat release. Specifically, the heat storage material temperature history value S at that time
Is compared with the criterion value S1, and if it is equal to or greater than the criterion value S1, it is determined that the heat is sufficiently stored. If it is lower than the determination reference value S1, it is determined that the heat storage amount is insufficient, and no heat is released at the time of starting. Heat storage material temperature history value S
Is the difference between the time when the temperature T of the heat storage material 13 is equal to or higher than the melting point (for example, 58 ° C. for sodium acetate trihydrate) during the operation of the internal combustion engine 1 and the temperature difference from the melting point (= heat storage material temperature). -Melting point). That is, assuming that the temperature of the heat storage material 13 changes as shown in FIG. 5, the area of the portion exceeding the melting point (shaded portion) is the heat storage material temperature history value S. The magnitude of the thermal storage material temperature history value S is determined by the thermal storage material 1
3 is correlated with the magnitude of the heat received, in particular, the heat stored as latent heat in the heat storage material 13. If the heat storage material temperature history value S is equal to or greater than the determination reference value S1, the entire heat storage material 13 becomes a liquid phase. It is presumed that it is in a state of being.

If the heat storage material temperature history value S is equal to or greater than the determination reference value S1 in step 2, the process proceeds to step 3, where the engine temperature (oil temperature, water temperature or catalyst temperature) TW is set to the reference value T.
It is determined whether it is equal to or less than W1. When the temperature is higher than the reference value TW1, the heat storage material 13 does not radiate heat. And
If the value is equal to or less than the reference value TW1, the process proceeds to step 4, where the
5 is applied with a voltage.

By applying a voltage as described above,
The heat storage material 13 in the supercooled state starts a phase change, and the latent heat corresponding to the heat of fusion is released. Due to this latent heat, the wall temperature of the cylinder surrounded by the heat storage material 13 rapidly rises, and the friction loss and the deterioration of the exhaust gas composition are eliminated.

After the heat is dissipated by applying the voltage, the process proceeds to step 5, where the above-mentioned heat storage material temperature history value S is reset to 0, and a series of start-up control is ended. The accumulation of the heat storage material temperature history value S is continued during operation of the engine by another routine (not shown).

FIG. 6 collectively shows whether or not to radiate heat at the time of starting, based on the relationship between the heat storage material temperature history value S and the engine temperature TW. As shown in FIG. When the engine temperature TW is equal to or greater than the determination reference value S1 and the engine temperature TW
Heat dissipation is performed only in the region of 1 or less.

FIG. 7 shows a different embodiment of the present invention. In this embodiment, no water jacket is formed on the cylinder block 11, and the cylinder block 11 extends over the entire length in the axial direction. A heat storage material 13 is provided.
Therefore, in this embodiment, more heat is given to the heat storage material 13. Note that a water jacket 19 is formed in the cylinder head 18 having a high heat load, similarly to the above-described embodiment, and cooling water is circulated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of a hybrid vehicle using both an internal combustion engine provided with a rapid warm-up device according to the present invention and an electric motor.

FIG. 2 is a time chart showing operating states of an internal combustion engine and an electric motor with respect to a vehicle speed of the hybrid vehicle.

FIG. 3 is a configuration explanatory view showing a configuration of a rapid warm-up device according to the present invention.

FIG. 4 is a flowchart showing a flow of a process when the internal combustion engine is started.

FIG. 5 is a time chart showing a relationship between a heat storage material temperature and a heat storage material temperature history value S.

FIG. 6 is a characteristic diagram showing a region where heat is released at the time of starting.

FIG. 7 is a configuration explanatory view showing a different embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Cylinder block 12 ... Heat storage material accommodating chamber 13 ... Heat storage material 14 ... Temperature sensor 15 ... Electrode 16 ... Control unit

Claims (6)

[Claims] An internal combustion engine contains a latent heat type heat storage material, and an electrode for promoting a phase change of the supercooled heat storage material is arranged in the heat storage material. A rapid warming-up device for an internal combustion engine, characterized in that the heat is applied to release heat. 2. The heat storage material is arranged around a cylinder of the cylinder block, and the heat absorption of the heat storage material cools the cylinder block side, and the cylinder head side is cooled by forced circulation of cooling water. The rapid warm-up device for an internal combustion engine according to claim 1, wherein 3. The internal combustion engine according to claim 1, further comprising means for detecting a temperature state of the internal combustion engine, and applying a voltage to release heat only when the internal combustion engine is in a predetermined low temperature state at startup. Engine quick warm-up device. 4. A means for determining whether or not latent heat is stored in a heat storage material based on a temperature history after heat release, and applying a voltage to release heat only when it is determined that heat is stored. The rapid warm-up device for an internal combustion engine according to any one of claims 1 to 3, wherein: 5. The rapid warm-up device for an internal combustion engine according to claim 1, wherein sodium acetate trihydrate is used as the heat storage material. 6. An internal combustion engine for a hybrid vehicle in which an electric motor for providing a driving force to a vehicle is provided together with the internal combustion engine, and the internal combustion engine is stopped and restarted based on vehicle operating conditions. The rapid warm-up device for an internal combustion engine according to claim 1.