Heating systems – Heat and power plants – Vehicle
Reexamination Certificate
1999-03-08
2001-04-24
Joyce, Harold (Department: 3749)
Heating systems
Heat and power plants
Vehicle
C237S012100
Reexamination Certificate
active
06220522
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an internal combustion engine having a combustion heater.
2. Description of the Prior Art
For example, Japanese Patent Application Laid-Open Publication No. 62-75069 discloses an art, in which an intake system of an internal combustion engine is provided with a combustion heater separately from an internal combustion engine body, raising a temperature of engine cooling water contained in a water jacket of the internal combustion engine by utilizing the combustion heat of the combustion heater, and thereby to attain the speeding up of warming the engine and enhancing a starting performance.
According to this art disclosed in the above Publication, the pipe is inserted into the water jacket of the internal combustion engine, and the combustion gas emitted from the combustion heater is allowed to flow into this pipe before starting up the engine. Then, the heat held by the combustion gas is thereby transmitted to the engine cooling water, and hence the temperature of the engine cooling water can be increased up to a desired temperature prescribed for each internal combustion engine by regulating a thermal quantity given to the engine cooling water.
“The desired temperature of the engine cooling water” implies a temperature enough to speed up the warm-up of the internal combustion engine and to enhance the starting characteristic thereof when the engine cooling water is warmed by the combustion heater and reaches this temperature.
It can be considered to enhance performances of a temperature raising mechanism for raising temperatures of the car room heater and of the internal combustion engine itself, and an intake air heating device and other temperature raising devices by raising a temperature of heat transmission fluid which is represented by the engine cooling water which has its temperature increased by the combustion heater as disclosed in the above Publication. In this case, in order to increase a heat exchange rate of the combustion heater to the heat transmission fluid, it may be sufficient to make a heat exchanging member of the combustion heater thin and elongate. In this instance, however, there might arise a problem that a water-flow resistance augments so that a flow rate to the temperature raising device is reduced or causes an increase of a drive loss of a pump for circulating the heat transmission fluid. Therefore, there must be naturally a limit for increasing the heat exchange rate. In such a case, since a sufficient heat exchange is not made, the temperature of the combustion gas of the combustion heater, which is introduced into the intake system of the internal combustion engine, inevitably becomes comparatively high. Hence, there might be caused thermal damages to the structures of the intake system.
Further, as demanded with times, decrease of a compression ratio of the internal combustion engine, namely, a low compression ratio, is required. However, this involves a problem that the starting characteristic of the internal combustion engine at a low temperature tends to decline.
Moreover, if trying to decrease the compression ratio of the internal combustion engine, the warm-up of the oil is delayed at the time of warming up the internal combustion engine because of a small exothermic quantity of the engine, resulting in such a problem that an engine friction becomes large and a fuel efficiency declines.
SUMMARY OF THE INVENTION
It is a primary object of the present invention, which was devised in view of the above-mentioned problems, to provide an internal combustion engine having a combustion heater capable of simply preventing thermal damages to the structures of the intake system and enhancing a low-temperature starting characteristic, even if a compression ratio of the internal combustion engine is decreased, by effectively utilizing the heat of a combustion gas of the combustion heater which is to be discharged into the intake system of the internal combustion engine, and capable of speeding up of warming of an oil even when the compression ratio of the internal combustion engine is decreased.
To accomplish the above object, according to a first aspect of the present invention, there is provided an internal combustion engine having a combustion heater which operates when the internal combustion engine is in a predetermined operating state, and enhancing a performance of a temperature raising device with a heat transmission fluid serving as a thermal source thereof, by warming the heat transmission fluid, and the internal combustion engine comprises: a combustion gas introducing passageway, through which the combustion heater is connected to an intake system of the internal combustion engine, for introducing a combustion gas emitted from the combustion heater into the intake system, and a cooling device for cooling the combustion gas flowing through the combustion gas introducing passageway.
Herein, “the time when the internal combustion engine is in the predetermined operating state” means that, at a cold time or at an extremely cold time, the internal combustion engine is being operated, or after starting the internal combustion engine, or when an exothermic quantity of the internal combustion engine itself is small (for example, when a fuel consumption is small) and when a heat quantity received by the engine cooling water is thereby small. Then, the cold time is a time when an outside air temperature is from about −10° C. to about 15° C., and the extremely cold time is a time when the outside air temperature is about −10° C. or lower.
The term “the heat transmission fluid” is referred to, for example, the engine cooling water.
Any sorts of “temperature raising devices” may be used on condition that these devices operate with the heat transmission fluid serving as a thermal source, for example, a device for speeding up the warm up of the internal combustion engine itself, or an intake air heating device for warming the intake air of the internal combustion engine, may be used. “The means for speeding up the warm-up of the internal combustion engine itself” implies a passageway for introducing the heat transmission fluid into the internal combustion engine, or a water jacket inside the internal combustion engine body. “The intake air heating device” is disposed in an intake passageway and functions therein as a heat exchanging unit.
For “the intake system of the internal combustion engine”, an intake pipe is suitable.
For “the cooling device”, it is preferable to use, for example, an exhaust gas cooler.
In the internal combustion engine having the combustion heater according to the present invention, the heat transmission fluid is warmed by the combustion heater, and the thus warmed heat transmission fluid serves to enhance the performance of the temperature raising device. Accordingly, the internal combustion engine having the combustion heater according to the present invention is capable of attaining a more enhanced performance of the temperature raising device than by the internal combustion engine not having the combustion heater.
Further, the combustion gas arriving at the internal combustion engine via the combustion gas introducing passageway from the combustion heater, is a gas after releasing the heat to the heat transmission fluid serving as the thermal source of the temperature raising device. Hence, the temperature of the combustion gas is no longer high, and, the combustion gas is further cooled off by the cooling device, and, therefore, there are no thermal damages to the structures of the intake system.
Moreover, the prevention of the thermal damages to the structure of the intake system can be effected simply by providing the cooling device, so that the manufacturing work is simplified and the productivity of the internal combustion engine having the combustion heater is consequently increased.
According to a second aspect of the present invention, in the internal combustion engine having the combustion heater according to the first as
Boles Derek S.
Joyce Harold
Kenyon & Kenyon
Toyota Jidosha & Kabushiki Kaisha
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