DE3133256A1 - Vehicle liquid-cooled internal combustion engine - Google Patents

Abstract

In order to meet the heating demand of a passenger motor vehicle without additional heating units and without adversely affecting the thermal efficiency of the internal combustion engine, even at low outdoor temperatures and even at low load, the internal combustion engine is provided with a thermal insulation, which largely prevents heat loss due to radiation. Rapid heating of the cooling water is thereby achieved on the one hand and on the other a large proportion of the waste heat from the internal combustion engine absorbed by the cooling water is made usable for heating of the vehicle.

Description

Liquid-cooled vehicle internal combustion engine

The invention relates to a liquid-cooled Vehicle internal combustion engine according to the preamble of claim 1. »

In the known internal combustion engines with 'high Efficiency, especially diesel internal combustion engines with direct injection, the heat content of that is enough Cooling liquid flowing through the heating system in particular at idle and in the lower partial load range low outside temperatures in order to ensure that the passenger compartment is adequately heated. Additional heating is expensive, has high operating costs and is due to the limited space available Difficult to accommodate in the engine compartment.

The invention is based on the object of a liquid-cooled To create vehicle internal combustion engine in which the heat loss absorbed by the cooling liquid to the greatest possible extent in the vehicle heater can be made usable.

According to the invention, this object is achieved in that the heat-radiating outer surfaces of the internal combustion engine are at least partially covered with thermal insulation.

The proposal according to the invention largely prevents the radiation of heat, which can amount to up to 25% of the heat of the coolant at low outside temperatures, and thus considerably increases the heat supply for the vehicle heating system. In addition, the cooling liquid heats up more quickly, which means that both the hot and cold

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running phase of the internal combustion engine as well as the period is shortened until the vehicle heating system starts to work effectively. After all, the higher temperature the coolant has a greater temperature difference in the insulation heat exchanger, which is smaller as a result compensated can be and better efficiency Has.

The heat insulation can be provided by a molded or The sprayed-on layer consists of a foam plastic, which is resistant to the occurring temperatures of around 120 C. As a suitable Ma I. er i a I Polyurethane foam has proven itself, but other heat-insulating materials, ie foamed Polycarbonates, polyesters, polyimides and the like can be used. Instead of applying an insulating layer a self-supporting shell construction made of foam plastic can also be provided, which surrounds the Bretmkra f trrujsehino as completely as possible.

Alternatively, the internal combustion engine can be surrounded by a capsule and the space between the outer surface of the internal combustion engine and the capsule be filled with a heat insulating material. The capsule can consist of sheet metal or plastic and the heat-insulating material can in turn a foam plastic or a mineral thermal insulation materialii)! like rock wool or the like.

Since the temperature of the exhaust pipes is generally higher than the decomposition temperature of the thermal insulation, at least if this is made of foam plastic, the exhaust pipes can be spaced apart, surround the thermal insulation penetrating pipe socket be. The space between the exhaust

pipes and the pipe socket can be connected to the coolant spaces be connected to the internal combustion engine, to make part of the exhaust heat usable for vehicle heating.

An embodiment of the invention is shown in the drawing shown, the a thermally insulated internal combustion engine in a schematically shown engine compartment of a passenger car shows. .

In the engine compartment 1 of a passenger vehicle 2, a water-cooled diesel internal combustion engine 3 is arranged, which drives the front wheels 5 of the motor vehicle ^{via a transmission 1} I. The internal combustion engine 3 has a cylinder block 6 with cooling water spaces 7, a cylinder head 8 with cooling water spaces 9), a valve cover 10 and an oil pan 11. The cooling water spaces 7 and 9 are connected to one another and to a cooler lk via lines 12 and 13. The cooler 14b can be short-circuited in the usual way by a thermostatic valve 14 'during the warm-up phase of the internal combustion engine and supplied with cooling air by an electrically driven fan 15. The cooling water spaces 7 and 9 are also connected by lines 16 and 17 to a heating heat exchanger 18 through which heating air can be blown into the passenger compartment 20 of the vehicle by means of a heating fan 19. The heating output can be regulated by a valve 21 in the line 17.

Essentially the entire outer surface of the internal combustion engine 3 is covered by a heat insulating layer in the exemplary embodiment 22 covered. This insulating layer is preferably made of a foam plastic, such as polyurethane, either in a form on the outer surfaces of the

Individual parts of the housing of the internal combustion engine 3, namely the cylinder block 6, the cylinder head 8, the valve cover 10 and the oil pan 11, sprayed on is or as a multi-part, self-supporting shell construction on the outer walls of these housing parts is attached.

The exhaust pipes 23 are each surrounded at a distance by a pipe socket 2k in order to protect the thermal insulation 22 from the hot exhaust pipes. The pipe sockets can be connected to the cooling water spaces 9 of the cylinder head 8. This simultaneously makes part of the exhaust gas heat available for heating the vehicle.

At 25 is the intake line, at 26 is the air filter designated!

In a modification of the illustrated embodiment, the thermal insulation of the internal combustion engine 3 can also take place in that a capsule made of sheet metal or plastic that surrounds the internal combustion engine at a distance is provided and the space between the capsule and the outer surface of the internal combustion engine is filled with a heat-insulating material that is resistant to the temperatures that occur. Both mineral thermal insulation materials are used here as well as heat-insulating plastics such as the aforementioned polyurethane.

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Claims (10)

215/81 AUDI NSU AUTO UNION AKTIENGESELLSCHAFT, Neckarsulm / Württ. Liquid-cooled vehicle internal combustion engine Claims flJ liquid-cooled vehicle internal combustion engine, in particular diesel internal combustion engine with direct injection, A vehicle heating system can be connected to ■ the rooms carrying the coolant, characterized in that the heat-radiating outer surfaces of the internal combustion engine (3) at least partially with thermal insulation (22) are covered. 2. Liquid-cooled vehicle internal combustion engines according to claim 1, characterized in that the thermal insulation (22) consists of a foam plastic layer is formed. 3 · Liquid-cooled vehicle internal combustion engine according to claim 2, characterized in that the foam plastic layer is applied directly to the outer surface the internal combustion engine (3) is applied. 4t. Liquid-cooled vehicle internal combustion engine according to claim 2, characterized in that the thermal insulation (22) is of a self-supporting Shell construction. Made of foam. 5. Liquid-cooled vehicle internal combustion engine according to one of the claims 2 to 4, characterized in that that polyurethane is used as foam plastic. "' 6. Liquid-cooled vehicle internal combustion engine according to claim 1, characterized in that the heat-radiating outer surfaces of the internal combustion engine (3) are surrounded by a capsule and the space between the outer surface of the internal combustion engine and the capsule of. one insulating material is filled. 7. Liquid-cooled vehicle internal combustion engine according to claim 6, characterized in that the capsule consists of sheet metal. 8. Liquid-cooled vehicle internal combustion engine according to claim 6, characterized in that the capsule consists of plastic. 9. Liquid-cooled vehicle internal combustion engine according to one or more of the preceding claims, characterized in that the exhaust Pipes (23) are surrounded by spaced apart, the Wärmei solierxmg dxxrchdringenden pipe sockets (2k) . 10. liquid-cooled vehicle internal combustion engine according to claim 9> characterized in that the pipe sockets (2k) are connected to the cooling liquid spaces (9).