WO2007074256A2

WO2007074256A2 - Compact heat engine

Info

Publication number: WO2007074256A2
Application number: PCT/FR2006/051313
Authority: WO
Inventors: Alain Lefebvre; Philippe Alson
Original assignee: Renault S.A.S
Priority date: 2005-12-22
Filing date: 2006-12-08
Publication date: 2007-07-05
Also published as: FR2895442A1; EP1963630A2; JP2009520910A; WO2007074256A3; FR2895442B1

Abstract

The invention relates to a heat engine for a motor vehicle, having at least one bank of parallel cylinders which are provided with a combustion chamber (10) and including a crankshaft (8) and a tank (14) for the engine lubrication oil. The invention is characterised in that the oil tank (14) is at least partially located along the axis of the cylinders at a position opposite the crankshaft (8) and beyond the combustion chamber (10).

Description

Compact heat engine.

The invention relates to the field of internal combustion engines of a motor vehicle, and in particular engines with a delocalized oil reserve.

In order to improve the protection of pedestrians during shocks caused by vehicles with a combustion engine, safety regulations make it necessary to increase the guard distance between the hood of the vehicle and the engine. Thus, when the pedestrian strikes the hood of the vehicle, it can deform gradually and the pedestrian is not directly confronted with a massive member such as the engine. In passenger cars of the minivan type, the driver 's seat is high enough for the hood of the vehicle covering the engine to have sufficient clearance distance. For conventional sedan type vehicles, the engine height should be less than

350 mm. However, for conventional sedans, it also requires large series engines and none of the 3 to 4 cylinder engines in line and with a cylinder capacity of between 1 liter and 1.6 liter does not have such a reduced height. U.S. Patent No. 5,063,895 (Porsche) discloses a V-8 engine where the lubricating oil flowing from the crankshaft falls into an oil pan. A main pump recovers the oil from the bowl and feeds the lubrication circuit of the main motor bearings. A second pump increases the oil pressure to lubricate the crankshaft. In such an engine, the oil reserve is arranged under the crankshaft and occupies a significant place in height. In addition, each of the two banks of cylinders requires a specific pump. Despite the distribution of the displacement on a large number of cylinders, and despite the inclination of the cylinder s, this type of motor has an excessive height requirement. In addition, the large number of pumps consumes energy unnecessarily.

US Patent 6,029,638 (Honda) discloses an engine where the lubricating oil, after passing through the engine, falls into the crank chamber from which it is pumped to an oil reservoir on the side of the engine. engine cylinder block. This increases the overall size of the motor unit in the width direction. The motor described is notably located in a boat and the axis of the engine cylinders is slightly inclined relative to the vertical. Here again the height occupied by the engine block is excessive.

The invention proposes a motor vehicle engine capable of being installed in a conventional sedan and allowing a guard distance, between the hood of the vehicle and the engine, sufficient to ensure the protection of pedestrians during an impact and this without consumption. excessive energy.

According to one embodiment, the engine, for a motor vehicle, has at least one bank of parallel cylinders provided with a combustion chamber and comprises a crankshaft and an oil reservoir for lubricating the engine. The oil reservoir is at least partly located along the axis of the cylinders at a position, opposite the crankshaft, beyond the crankshaft.

Thanks to the position of the oil reservoir, the engine can be almost lying in the vehicle. This allows a sufficient guard distance between the vehicle hood and the engine. Such a provision also allows integration of the engine under a vehicle floor.

Advantageously, the engine comprises a casing provided with a crank chamber having a crankshaft low point adapted to receive the oil flowing inside the engine casing. Engine includes a recovery pump for drawing the oil arriving at the crankshaft low point and for supplying the oil reservoir.

According to one embodiment, the motor comprises a strainer comprising two suction inlets disposed in two opposite portions of a motor housing and / or the oil reservoir. The strainer comprises an inertial closure member adapted to be driven in the direction connecting the two inlets and in the same direction as the oil when the vehicle is accelerated. The closure member is able to obstruct the entrance in the opposite direction to said acceleration. The direction connecting the two intake ports of the strainer may be transverse to the direction of travel of the vehicle.

This embodiment further reduces the height of the low point where the oil flows. As the vehicle rotates, accelerates, ascends or descends, the oil moves inertia in a corner of the crank chamber. Thanks to the two suction inlets selected by the inertial closing device, the strainer always draws oil without the need to trap the oil in a deep low point.

Advantageously, the engine comprises a lubrication pump intended to draw oil from the oil reservoir and to supply lubrication circuits to the engine.

According to another embodiment, the engine comprises a cylinder head provided with a valve chamber having a low point of the cylinder head. The engine includes a conduit connecting the low end of the cylinder head to the oil reservoir to recover the oil flowing inside the valve chamber.

Advantageously, the oil reservoir is monobloc with the cylinder head, or is fixed on the cylinder head. Advantageously, the engine comprises a settling tank for receiving vapors from a crank chamber and / or a valve chamber, the settling tank being connected to an engine air intake circuit, the motor comprising a conduit connecting the settling vessel to the oil reservoir to recover the oil deposited in the settling vessel.

According to one embodiment of the invention, the vehicle comprises an engine in which at least one cylinder axis of the engine is inclined with respect to a horizontal plane of the vehicle by an angle of less than 30 ° and preferably of - 10 °. at + 10 °, the cylinder head being above the crankshaft of the engine.

Other features and advantages of the invention will appear on reading the detailed description of an embodiment taken by way of non-limiting example and illustrated by the appended drawing, in which the single figure is a diagrammatic representation of an engine according to the invention.

As illustrated in the figure, the engine essentially has a bank of parallel cylinders 1 provided with a cylinder head 2 and a lower part 3 of the engine, which part 3 comprises a cylinder block 4 and a crankcase 5. Inside each cylinder moves a piston 6 and a connecting rod 7. The head of the rod 7 drives a crankshaft 8 surrounding a crankpin 9 crankshaft. The small end is rotatably mounted on an axis 6a integral with the pi ston 6. The crankshaft 8 rotates in a crank chamber 8a. The piston 6 delimits, in the upper part of the cylinder 1c, a combustion chamber 10. The upper part 1 1 of the combustion chamber 10 is integral with the cylinder head 2 and the cylindrical side wall is part of the cylinder block 4. Two shafts with cam 12 and 12a, driven in rotation by the crankshaft 8, put in translation movement of the valves corresponding 13 and 13a with pawls or pushers not shown. The set of mechanisms ranging from the camshafts 12 and 12a to the valves 13 and 13a evolves in a chamber 23a of the cylinder head 2, represented by a local section in the figure. An oil reservoir 14 is attached to the cylinder head 2 and located below said cylinder head 2. A lubrication pump 15 is arranged on one side of the tank 14 and is driven by the camshaft 12a. A settling tank 16 is formed inside the oil tank 14, in its upper part. The assembly comprising the tank 14, the settling tank 16 and the pump 15 is fixed to the cylinder head 2 by a fixing face 14a.

A very high pressure fuel pump 17 for a common rail feed device is disposed in the upper part of the cylinder head 2 and is driven by the camshaft 12. A starter 18 is arranged on the crankcase 5 and drives a starter ring 18a integral with the crankshaft 8.

The bank of parallel cylinders is inclined at an angle of about 1 ° relative to the horizontal plane of the vehicle, that is to say with respect to a running surface of the vehicle. The angle of inclination determines the height of the engine, ie the difference in overall height between the bottom of the starter ring 18a and the top of the fuel pump 17. The starter ring 18a is itself a direct consequence of the size of the starter 18 being located as close as possible to the crank chamber 8a but necessarily outside. Alternatively, the crank chamber 8a may be smaller in size and the angle of inclination larger, or vice versa.

The lubrication circuits of the engine will now be described. The lubrication pump 15 draws oil from a low point of the oil tank 14 and the injected pressure in a conduit through an oil filter 19 arranged on a wall of the tank 14 and feeds in parallel a main conduit 20 towards the cylinder block 4 and a secondary conduit 21 towards the cylinder head 2. The main conduit 20 of lubrication feeds a nozzle 22 integral with each cylinder for throwing oil on the small end located inside the piston 6 when the latter is in maximum recoil. The main duct 20 also feeds, by unrepresented tunnels and formed in the cylinder block 4, the bearings on which the crankshaft 8 is mounted. Likewise, unrepresented channels run along the crankshaft 8 and make it possible to bring the oil to guide ducts 9 for guiding between the small end and the crankshaft 8. The secondary duct 21 joins, by ducts (not shown), the guide bearings of the camshafts 12 and 12a as well as the axes of rotation of the latches and the guide means in translation of the valves 13 and 13a. These various lubrication locations cause oil to seep into the chamber 23a of the cylinder head 2. The oil is recovered at a low point of the cylinder head 23. Likewise, the oil dripping from the lower part of the piston 6 after having been projected by the nozzle 22 flows along the crank chamber 8a to a low point of the crankshaft 24. About 70% of the oil consumption of the engine 1 is intended for the lubrication of the lower part of the engine 3 , the oil flowing in the crankshaft low point 24 is recovered by a recovery pump 25 towards the oil reservoir 14. The oil reservoir 1 4 is located just below the cylinder head 2, the recovery of the oil oil arriving at the low point of the cylinder head 23 is by gravity to the tank 14 through a recovery conduit 26. This arrangement of the oil tank 14 makes it possible to omit an additional oil pump, which is suitable good for mass production vehicles. We will now describe the fat vapor recovery circuit. Inside the lower part of the engine 3, the atmosphere in the crank chamber 8a is saturated with oil droplets and mixed with vapors possibly escaping from the combustion chamber 10 despite sealing segments between the piston 6 and the cylinder block 4. A high suction point 27 is formed in the crank chamber 8a to suck the greasy vapors. A duct 28 operated in the lower part of the engine then in the cylinder head 2 connects the high suction point 27 to the settling tank 16. Similarly, a breech duct 29 connects the chamber of the cylinder head 2 to the same settling tank 16 , and makes it possible to recover the vapors escaping from the guiding means of the valves 13 and 13a and their controls. The air supply circuit of the combustion chamber 10 comprises an intake port 30, a turbocharger 31 and an intake circuit 32 controlled by the valve 13. A suction pipe 33 connects the settling vessel 16 to the air intake circuit upstream of the turbocharger 31. In a variant, the air intake circuit 32 does not include a turbocharger. The suction duct 33 joins the air intake circuit by a device of the not shown venturi type, so that the high flow rate of air in the intake circuit 32 creates a slight suction flow rate that makes it possible to recover fat vapors from ^the inside of the crank chamber 8a and the cylinder head chamber 2. Through s baffles 34 mounted in the settling vessel 16, fat vapors from inside the engine are discharged to a portion of their oil, the remainder being burnt in the combustion chamber 10. The portion of oil recovered by the settling tank 16 flows into the oil reservoir 14 through a siphon-shaped conduit 16a allowing the oil to go from the settling tank 16 to the oil reservoir 14 despite the pressure difference and despite fluctuations in inclination.

A feed pump 35 for an oil pump, for example of the type described in the patent application FR 2 860 548 can be used in the crankshaft low point 24. The low point 24 has the shape of a channel parallel to the crankshaft. crankshaft axis 8, the end points of this channel are provided with a strainer 35 having two inputs 36 and 36a. An inertial closure member may be driven in the direction connecting the two inputs 36 and 36a when the vehicle is accelerated, for example a gyratory acceleration. The displacement of this inertial member is therefore parallel to the displacement of the oil inside the channel forming the low point of crankshaft 24. When the vehicle rotates for example to the right, the oil accumulates on the left side of the low point 24 and the right inlet 36 of the strainer 35 is closed, the recovery pump 25 does not pump in the vacuum, which has the advantage of not introducing a discontinuity in the supply of the tank 14 of oil . Such a strainer limits the emulsion of the oil, its vaporization and the consumption of oil by the engine.

If we consider a lower plane, parallel to the running surface of the vehicle and tangent to the lower part 3 of the engine and an upper plane parallel and tangential to the cylinder head 2 or massive equipment directly attached to the cylinder head 2, the distance between these two plans is reduced to allow a guard space between the hood of the vehicle and the engine. The fact that the oil reservoir 14 is located between the lower plane and the cylinder head 2 makes it possible to approach the axis of the crankshaft of the lower plane and allows the choice of either tilting the engine less or reducing the distance between the engine. both plans. In another embodiment, the engine may be equipped with a fuel pump, or a direct injection engine pump, or a multipoint injection engine pump.

Claims

1 -A thermal engine for a motor vehicle having at least one bank of parallel cylinders provided with a combustion chamber (10) and comprising a crankshaft (8) and an oil tank (14) for lubricating the engine, characterized by the fact that the reservoir (14) of oil is at least partially located along the axis of the cylinders at a position, opposite the crankshaft (8), beyond the combustion chamber (10).

2 -Engine according to claim 1, comprising a housing (5) provided with a crank chamber (8a) having a crankshaft low point (24) adapted to receive the oil flowing inside the housing (5). ) of the engine, and comprising a recovery pump (25) for drawing oil arriving at the crankshaft low point (24) and to supply the reservoir (14) of oil. 3 -Elter according to claim 1 or 2, comprising a strainer (35) having two suction inlets (36, 36a) arranged in two opposite portions of a housing (5) of the engine (1) and / or reservoir (14) of oil, and comprising an inertial closure member adapted to be driven in the direction connecting the two inputs (36, 36a) and in the same direction as the oil when the vehicle undergoes acceleration, the organ shutter being able to obstruct the entrance in the opposite direction to said acceleration.

4 -Elter according to claim 3, wherein the direction connecting the two inlet (36, 36a) of suction strainer (35) is transverse to the direction of movement of the vehicle.

5 -Elter according to one of the preceding claims, comprising a lubrication pump (15) for drawing oil from the reservoir (14) of oil and to supply circuits (20, 21) for lubricating the engine. 6 - Engine according to one of the preceding claims, comprising a cylinder head (2) provided with a valve chamber having a low point of the cylinder head (23), the engine comprising a conduit (26) connecting the low point (23) of cylinder head (2) to the tank (1 4) of oil to recover the oil flowing inside the valve chamber.

7 -Elter according to claim 6, wherein the oil reservoir is integral with the cylinder head (2), or is fixed on the cylinder head (2).

8 - A motor according to one of the preceding claims, comprising a settling vessel (16) for receiving vapors from a crank chamber (8a) and / or a valve chamber, the settling vessel (16). ) being connected to an engine air intake circuit, the engine comprising a conduit connecting the settling vessel to the oil tank for recovering the oil settling in the settling vessel.

9 - Vehicle comprising a motor according to one of the preceding claims, wherein at least one cylinder axis of the engine is inclined relative to a horizontal plane of the vehicle by an angle less than 30 ° and preferably from - 10 ° to + 10 °, the yoke (2) being above the crankshaft (8).