US2248544A - Air supply means for diesel engines - Google Patents

Description

July 8, 1941. H. MARUHN AIR SUPPLY MEANS FOR DIESEL ENGINES Filed Feb. 24, 1939 INVENTOR /%=rAe,/V m// BY I ATTORNEY Patented July 8, 1941 AIR SUPPLY MEANS FOR DIESEL ENGINES Herbert Maruhn, Stuttgart-Bad Cannstatt, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Application. February 24, 1939, Serial No. 258,211 In Germany February 26, 1938 Claims.

The invention relates to Diesel. engines or other air-inducing or air-compressing internal combustion engines, particularly for motor vehicles; An important object is to provide means for-increasing the temperature of the air which influences engine cooling, for example, air located under the engine bonnet, and an independent air intake for the admission to the engine of cold combustion air.

The Diesel engine is'particularly sensitive to excessive cooling and its temperature condition ought not to pass below a certain lower limit. High cooling water temperatures are desirable for the engine output and for readiness in start- By the use of a radiator shutter or a corresponding control device, the air under the engine bonnet and also the radiator may be kept sufficiently warm, so that the radiator acts as a heat accumulator. Such an arrangement is particularly advantageous in winter and is essential for quick re-starting of the engine with a cold outside temperature.

0n the other hand, if air at comparatively high temperature is drawn in by the engine, the charging and therewith the output of the engine become less than if air at lower temperature is drawn in. However, whereas there is the danger with carburetter engines that the formation of:

the mixture is impaired if the air drawn in falls rubber cushions c and d which permit the engine to swing about a longitudinal axis C-D' passing approximately through thecentre of gravity. Arranged in front of the engine is the radiator e to which the cooling water warmed in the engine flows through the passage I. From the radiator e the cooling water flows through -the passage g to a pump h driven by the engine,-

which pump delivers the cooling water back through the pipe-connections 5 to the coolingwater space of the engine and thus maintains it constantly in circulation. The passages and g resiliently in known manner so that the engine below a certain temperature and consequent dissociation of the mixture or condensation ofthe fuel is to be feared, it is possible with Diesel engines to supply as cold air as possible to the engine with particular advantage, since this engine draws in and compresses air only. For this reason, the invention provides in combination, a radiator shutter or control and a combustion air intake disposed outside of the engine space or outside of the radiator shutter so that the thermal condition of the admitted combustion air remains unaffected by the closing of the radiator shutter and the engine receives combustion air of as low a temperature as possible. I Preferably, the entry of the air into the engine inlet passage takes place at a point of comparatively high external air pressure, particularly at the front end of the vehicle in front of the radiator. The charging and the output of the engine may be further improved by this means.

One embodiment of the invention by way of example, is illustrated diagrammatically in th annexed drawing.

In the drawing, the Diesel engine b is mounted on the frame a, for example by means of .the

can swing about the axis C-D.

The engine is arranged under the bonnet'i. Preferably the engine space is also closed below by a bottom plate is. Disposed in front of the radiator is the radiator protecting grid Z and between the two there is aradiator shutter of the louvre type formed by adjustable flaps m. The flaps are eachniounted rotatably about shafts n which runhorlzontally in thedrawingbut in practice will generally run vertically. The

individual fiaps'are connected together by a rod 0 and are adjustable together by a two armed lever arm 12 which can be actuated from the drivers seat by a rod q, for example a rod adjustable lengthwise by the aid of a ratchet device r and handle s. p

The combustion air for the engine is taken in at the front end of. the radiator by a funnel t and is conducted through the upper part of the radiator space and by way of a flexible passage 10 to the air filter u whence the air passes into the suction pipe 11) of the engine. The fuel is supplied by the, fuel pump a: to the injection nozzles 1 in a manner known per se, it being possible, for example, for the fuel to be injected into pre-combustion chambers.

By adjustably opening or closing the flaps m of the radiator shutter, the temperature under-J I neath the engine bonnet can be maintained at a desired favourable value without the temperature of the induced combustion air being practically influenced thereby. Even with the shutter closed and with a high temperature inside the engine space, cold combustion air and consequently a high weight of air are drawn in. Experiments have shown that the weight of air then drawn in is approximately 5-15% greater than when the air is drawn in from underneath the engine bonnet. The output of the engine is increased also in similar fashion.

Particularly advantageous in combination with the provision of the radiator shutter is the provision of adjustable flaps in the side walls of the engine space, these flaps being preferably adjusted at the same time as the radiator shutter by a common actuating linkage. This is effected in simple fashion by jointing a connecting rod 8 to the one arm of the two-armed lever p adjustable by the rod q, the rod 8 being engaged with the flaps 1. A particularly precise control of the quantity of air flowing through the engine space can thus be achieved, and disadvantageous loss of heat from the engine or cooling water can be avoided in an especially effective fashion.

Furthermore, in combination with the radiator shutter, the cooling water heated by the closure thereof may be utilised for heating the interior space of the vehicle. The heated air underneath the engine bonnet may also serve the same purpose, the air being, for example, caught by a funnel after its passage through the radiator and conducted to the interior space of the vehicle.

It is advantageous to bring the suction opening t for the combustion air as near as is permitted by the constructional arrangement to the axis of swinging C--D of the engine, so that the passage 11. experiences as small relative movements as possible at the points of connection. For example, the suction passage t, u for the combustion air may also he carried directly through the radiator and the radiator shutter. Moreover, it may'also be connected rigidly to the engine and partake in its swinging movements.

In some cases, the inlet opening to the suction passage for the combustion air may also be disposed at some point other than the front end or the vehicle, but it is advantageous to provide the inlet opening at a point of comparatively high external-air pressure. Thus, with the constructional example illustrated in the drawing,

the dynamic pressure arising at the front end will produce a certain additional charging of the engine or reduce the loss of output caused by the I claim:

1. In a vehicle driven by an engine of the compression-ignition type, means forming an engine compartment at the front of the vehicle, including a hood and a radiator grill provided with a plurality oi!v relatively narrow apertures and one relatively large opening, an adjustable louver positioned immediately behind the narrow apertures of said grill without obstructing said large opening, a radiator positioned immediately behind said louver, conduits for supplying cooling water to and from said radiator, from and to said engine, a funnel having its mouth surrounding said opening and its tube extending rearwardly, means for connecting said tube for supplyin combustion air to said engine, means for introducing fuel into said engine independently of said combustion air, and means for adjusting said louvers, whereby the temperature about said engine in said engine space may be raised to a predetermined height, while relatively cold air will be supplied interiorly of said engine, independently of the temperature within said engine space.

2. The combination according to claim 1, wherein said opening is positioned at a point of relatively high external air pressure resulting from movement of the vehicle.

3. The combination according to claim 1, in combination with exit shutters along the sides of said engine space, and means for controlling said shutters simultaneously with said louvers.

4. In a vehicle driven by an engine of the compression-ignition type, means forming an engine compartment at the front of the vehicle, including a hood having air inlet openings and air outlet openingsjadjustable means for throttling and closing theair inlet opening in order to raise the temperature about said engine in said compartment, anair inlet conduit for an! plying combustion air to said eng e. independently, of said adjustable means for throttling and closing the air. inlet opening; said conduit having a separate" air inlet opening outside of said engine compartment, thereby supplying relatively cold air interiorly of the engine independently of the temperature within said space and preventing air from entering the interiorof the engine out of said engine compartment, and means for introducing fuel into said engine independently a of said combustion air.

5. In a vehicle, the combination'acoording to claim 4, in combination .with adjustable means for closing the air outlet opening so as to prevent my invention 8 d f ned in the cl ms which air from flowing out of said engine compartment.

follow.

HERBERT MARUW.

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