JP2000045888A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dual fuel engine which consumes electric power or fuel by a low volume, and which can urgently be started for emergency. SOLUTION: In an internal combustion engine such as an engine (dual fuel engine) which has an intake-air heating device 3 and in which gas fuel as main fuel is ignited by a pilot burner with the use of liquid fuel, or a lean burn gas engine, hot water is fed into the intake-air heating device 3 from a hot water tank 4 for reserving cooling water for the engine so as to heat intake-air, and the hot water tank 4 is kept in hot insulation by a hot insulation heat source 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine, and more particularly, to a dual fuel engine having a dual fuel which is provided mainly with a gas fuel and has a pilot fuel ignited with a liquid fuel, provided with an intake heating device, and a lean burn gas engine. More specifically, the present invention relates to a starting performance improving device for improving the starting performance of such an internal combustion engine.

[0002]

2. Description of the Related Art As a prior art, for example, a system using a dual fuel engine will be described. Gas fuel as main fuel (primary fuel) and liquid fuel (for example, light oil)
In the gas engine 1 in which the ignition source is the ignition source, the compression ratio cannot be made large unlike the diesel engine, so that the starting performance is not so excellent. Therefore, as shown in FIGS. 4 and 5, the intake system 2 for supplying the air-fuel mixture to the engine is provided with an intake heating device 3A (or 3B) for heating the intake A with an electric heater or a burner.

[0003] Such an intake heating device 3A (3B) consumes extra electric power or fuel, and in the case of a common use for disaster prevention, a commercial power supply cannot be used for an emergency start. It is necessary to use an oil burner provided with B or an oil tank T, which is not economical.

Further, in the conventional lean burn engine, at the time of starting and warming up, the starting gas is supplied to the main chamber of the engine in a thicker state than at the time of steady state, thereby ensuring the startability. Therefore, there is a problem that thermal efficiency is poor at the time of starting and warming up.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an internal combustion engine which consumes less power or fuel, is economical, and can be started in an emergency.

[0006]

SUMMARY OF THE INVENTION An internal combustion engine according to the present invention includes an intake air heating device interposed in an intake system, a hot water tank for storing cooling water, and a supply of hot water from the hot water tank to the intake air heating device. And an intake piping system configured to heat the intake air, and a heat retaining heat source for retaining the temperature of the hot water tank.

Here, as the internal combustion engine of the present invention, a dual fuel engine having a dual fuel using a gas fuel as a main fuel and a liquid fuel as a secondary fuel is preferable.
Alternatively, a lean burn gas engine is preferred.

According to the internal combustion engine of the present invention having such a configuration, the cooling water, which has become high in temperature during the operation of the dual fuel engine or the lean burn gas engine, is stored in the hot water tank even after the operation is stopped. It is kept at a predetermined temperature. The hot water is supplied to the intake air heating device and exchanges heat with the intake air at all times or at the time of starting, and the intake air is heated to improve the starting performance of the dual fuel engine and the lean burn gas engine.

Further, since the hot water tank communicates with the cooling water jacket of the dual fuel engine, the dual fuel engine or the lean burn gas engine used in the internal combustion engine of the present invention is always in a warm-up state at the time of start-up. The starting performance is also improved from this point.

Further, according to the internal combustion engine of the present invention, the start-up performance is improved and wear can be prevented, so that it is suitable as an emergency engine.

In addition, when the present invention is applied to a lean burn gas engine, it is not necessary to supply a rich gas at the time of starting and warming up as in a conventional lean burn gas engine. Even if it does, the time can be made very short, so that there is an advantage that high efficiency operation can be achieved at an early point.

In practicing the present invention, as a heat retaining heat source, a hot water tank may be directly heated by a heater or a burner, or may be indirectly heated by exchanging heat with hot water of a gas water heater.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the illustrated embodiment,
An embodiment using a dual fuel engine as the internal combustion engine of the present invention is described. In FIG. 1, reference numeral 1 denotes an engine (dual fuel engine: a dual fuel engine used in the internal combustion engine of the present invention) using light oil as a pilot ignition source and gas as a main fuel. The heating device 3 is interposed. A hot water tank 4 communicating with a cooling tower C (not shown) is provided, and cooling water W of the engine 1 is circulated between the cooling water pipe 11 and the hot water tank 4. Hot water (cooling water W) is circulated from the hot water tank 4 to the intake air heating device 3 through the intake air heating pipe 12 to exchange heat with the intake air A.

Further, a water heater 5 is provided as a heat-retaining heat source, and heated hot water is circulated through a heat exchanger 6 provided in the hot-water tank 4 through a heat-retaining heat source pipe 13 to keep the hot water tank 4 at a predetermined temperature.

With the above configuration, during operation of the engine 1, the cooling water W is temporarily stored in the hot water tank 4, and furthermore,
Cooled by cooling tower C. Then, after the engine 1 is stopped, the high-temperature cooling water W is stored in the hot water tank 4, and when the temperature drops, the hot water is sent from the water heater 5 and the heat exchanger 6 stores the hot water in the hot water tank 4. The cooling water W is kept at an appropriate temperature. Therefore, when the engine 1 is started, even if it is urgent, the intake heating device 3
Is heated by hot water through the heating pipe 12 and can be easily started. The hot water W in the hot water tank 4 circulates immediately in the engine 1 itself, so that the engine 1 can be started up immediately and wear can be prevented.

The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. There is provided a branch conduit 9 which opens to the opening.

According to this embodiment, at the time of startup, the throttle valve 15 of the exhaust pipe 7 is throttled, and the on-off valve 16 is opened to operate.
Therefore, in addition to the intake air heating by the hot water W, the intake air A supplied to the engine after a part of the exhaust E is recirculated from the branch pipe 9 to the intake system 2 is heated. improves.

Further, in the embodiment shown in FIG. 3, the exhaust branch pipe 21 does not return to the intake system 2 but exchanges heat with the intake system 2 in the heat exchanger 22 and discharges the exhaust branch pipe as compared with the embodiment shown in FIG. It is configured as follows.

Therefore, in this embodiment, the exhaust heat is transmitted to the intake A in a clean state without the exhaust E mixed into the intake A, and the starting performance and the start-up performance are improved in combination with the heating by the hot water W.

The illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention. For example, in the illustrated embodiment, only an embodiment using a dual fuel engine is described, but the present invention is also applicable to a lean burn gas engine.

[0021]

The effects of the present invention configured as described above are enumerated below. (1) Even after the operation of the engine is stopped, the cooling water is stored in the hot water tank at a predetermined temperature by the heat retaining heat source, and the intake water is heated by the hot water. Can be started. (2) Since power or fuel is not required for intake air heating as in the conventional case, energy saving can be achieved. (3) Since the warm water stored in the warm water tank circulates also to the internal combustion engine, for example, the dual fuel engine or the lean burn gas engine, the warm-up operation is not required. (4) Since the hot water stored in the hot water tank circulates also in the internal combustion engine, for example, the dual fuel engine or the lean burn gas engine, wear of the engine can be prevented. (5) A more effective system can be constructed by combining a technique of returning a part of the exhaust gas to the intake air or a technique of exchanging heat with the exhaust air and the intake air.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram showing still another embodiment of the present invention.

FIG. 4 is a view for explaining intake air heating by a conventional electric heater.

FIG. 5 is a diagram illustrating intake air heating by a conventional burner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake system 3 ... Intake heating device 4 ... Hot water tank 5 ... Water heater 6 ... Heat exchanger 7 ... Exhaust pipe 9, 21 ... Branch pipe DESCRIPTION OF SYMBOLS 11 ... Engine cooling water pipe 12 ... Intake heating pipe 13 ... Heat insulation heat source pipe 15 ... Throttle valve 16 ... Open / close valve 22 ... Exhaust heat exchanger 13 ... Heat insulation heat source pipe

Claims (3)

[Claims] 1. An intake heating device interposed in an intake system, a hot water tank for storing cooling water, and hot water in the hot water tank is supplied to the intake heating device to heat the intake air. An internal combustion engine provided with an intake piping system and a heat retaining heat source for keeping the hot water tank warm. 2. The internal combustion engine according to claim 1, wherein the internal combustion engine is a dual fuel engine having a dual fuel using a gas fuel as a main fuel and a liquid fuel as a secondary fuel. 3. The internal combustion engine of claim 1, wherein said internal combustion engine is a lean burn gas engine.