Hybrid vehicle powertrain

Abstract

To improve a bending and twisting resonance frequency of a power train system by reviewing a loading position and a loading method of a motor-driven auxiliary machine for a hybrid vehicle, and provide the power train in a mode with superior effects of suppressing vibration noise of the vehicle.SOLUTION: A power train includes a cylinder block 3 constituting an engine body 1, and a housing part 10 constituting a transaxle 2. A rear flange 15a provided on the cylinder block 3 is fixed to a front flange 15b of the housing part by using a group of bolts 17. A bracket 26 widening largely to an intake side surface part is fixed to the intake side surface part of the cylinder block 3 by using bolts 27-32, and a rear boss part 36 provided on the bracket 26 is fixed to a first mission case 10 by using a bolt 37. The bracket 26 has a tray shape and high rigidity. A compressor 47 for a motor-driven air conditioner is fixed to the bracket 26.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The invention of the present application relates to a power train (power unit) of a hybrid vehicle.

Background Art

[0002] In a hybrid vehicle, in addition to an engine, at least one motor generator for power generation and driving, which increases the weight, is mounted in a transaxle.

[0003] The power device of a vehicle that combines an engine body and a transaxle is called a power train. However, the power train of a hybrid vehicle is characterized in that the weight of the transaxle part is larger than that of the power train of a non-hybrid engine.

[0004] That is, in the power train of a non-hybrid engine, the weight of the engine body is usually larger than that of the transaxle. Therefore, the center of gravity of the power train is generally on the engine body side. However, in the power train for a hybrid vehicle, since the transaxle is heavy, the center of gravity has moved to the transaxle side.

[0005] In both hybrid vehicles and non-hybrid vehicles, the transaxle is fixed to the rear surface of the engine body by a group of bolts. However, in the power train for a hybrid vehicle, due to the large weight of the transaxle, there is a problem that a large load (bending or torsional load) is applied to the fastening part between the engine body and the transaxle, and the cylinder block and oil pan constituting the engine body.

[0006] Therefore, some reinforcing means are necessary. As an example of such reinforcing means, Patent Document 1 discloses fixing the side surface of a cylindrical stiffener surrounding a drive shaft fixed to a transmission to an engine in a power train (power unit) for a front-engine front-wheel-drive (FF) vehicle in which the drive shaft extends from the transmission.

[0007] On the other hand, automobile engines generally come with an air conditioning compressor, which in non-hybrid vehicles is typically driven by an accessory drive belt wrapped around the crankshaft pulley. However, because a portion of the belt-driven air conditioning compressor protrudes forward from the engine body (cylinder block), the air conditioning compressor is located far from the center of gravity of the powertrain.

[0008] Therefore, when applied to a hybrid vehicle powertrain, which is heavier due to the addition of an electric motor for driving heavy objects and whose center of gravity has shifted towards the transaxle, the offset amount of the air conditioning compressor from the center of gravity of the powertrain, which has shifted towards the transaxle, increases compared to a conventional engine. This increases the excitation force of the powertrain and amplifies the vibration G acting on the air conditioning compressor.

[0009] Regarding the problems with air conditioner compressors, Patent Document 2 discloses, for non-hybrid engines, that the front and rear of the electric compressor are reversed and the heavy drive motor is positioned closer to the center of gravity of the engine body. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Publication No. 5-1456 [Patent Document 2] Patent No. 4230010 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] Patent Document 1 discloses a reinforcement technique in which the lower part of the transmission is fastened to the engine body with a stiffener. However, Patent Document 1 lacks a coupling flange on the engine body (oil pan) side that connects the transmission mating surface below the crankshaft (sheet metal oil pans cannot structurally form coupling flanges). Therefore, it is a structure that avoids interference between the stiffener, which is set to compensate for insufficient coupling rigidity with the engine body, and the drive shaft, which is arranged along the oil pan unique to FF vehicles. It is therefore difficult to apply to a powertrain reinforcement structure for a hybrid vehicle, such as the embodiment of the present invention, in which the oil pan on the engine body side is an aluminum oil pan that also has a coupling flange below the crankshaft.

[0012] On the other hand, Patent Document 2 discloses reversing the front-to-back orientation of the motor and compressor in order to bring the motor driving the heavy air conditioner compressor closer to the center of gravity of the engine body. However, this is intended to reduce the excitation G applied to the motor due to powertrain vibration, and is not intended to improve the resonant frequency of the powertrain system by moving the position of the air conditioner compressor to the rear. It is difficult to say that this will improve the coupling rigidity of the hybrid vehicle powertrain and contribute to improving the resonant frequencies of bending and torsion.

[0013] The present invention was made against this backdrop, and aims to disclose a technology that is superior in mass efficiency and vibration suppression effect regarding the coupling rigidity of a hybrid vehicle powertrain by improving the arrangement of electrified auxiliary equipment and the fastening structure of the mounting bracket for the electrified auxiliary equipment. [Means for solving the problem]

[0014] The present invention comprises multiple components, each of which is specified in a separate claim. Of these, the invention of claim 1 is: "An engine body comprising a cylinder block, cylinder head, oil pan, and head cover, Fixed to one end face of the engine body facing the crank axis direction transaxle and , a bracket to which an electric auxiliary device is attached is located on one side of the engine body that is perpendicular to the crank axis and cylinder bore axis and faces left-right, It has, The aforementioned engine body Of these, the portion located at one end to which the transaxle is attached and on the side of the one side is formed as an enlarged portion that extends outward in the left-right direction toward the transaxle, and the enlarged portion is fastened to the transaxle with bolts. It is a powertrain, The bracket is formed in the shape of a tray having a peripheral wall, and inside it is formed a boss portion and a group of ribs extending radially from the boss portion and connected to the peripheral wall. The bracket is positioned so as to partially overlap the enlarged portion of the engine body. 」 It has such a configuration.

[0015] The invention according to claim 2 is, in claim 1, 「 A group of outer peripheral bosses for fixing the electric auxiliary equipment is formed on the outer periphery of the bracket, two of the outer peripheral bosses are connected by an inclined rib, and the inclined rib and the one rib extending in the radial direction intersect. 」 It has such a configuration.

[0017] In the present invention, as an example of an electric auxiliary machine, an air conditioner compressor can be cited ru. Shi An electric auxiliary machine disposed on the intake side surface portion of the cylinder block to can be attached to the racket. In this case, the electric auxiliary machine may be fixed only to the bracket, or a part thereof may be fixed to the engine body such as the cylinder block and the remaining part may be fixed to the bracket.

[0018] It is also possible to fasten the electric auxiliary machine and the bracket together to the engine body such as the cylinder block with bolts.

Advantages of the Invention

[0021] This application In the invention, the coupling rigidity between the engine body and the transaxle can be improved by the bracket. That is, the rigidity against bending and torsion of the power train system can be improved. Therefore And, the decrease in the resonance frequency of the bending and torsion modes of the power train system can be suppressed, and as a result, the deterioration of vehicle body vibration and noise can be suppressed.

[0022] In particular, as in the embodiment, when the bracket to which the electric auxiliary machine (air conditioner compressor) is attached is connected and fixed to the oil pan rail portion, which is a high-rigidity portion in the cylinder block, and the cylinder head connecting portion on the upper surface of the block, even if the heavy electric auxiliary machine is attached to the bracket, the decrease in the resonance frequency of the electric auxiliary machine alone can be suppressed, and the reinforcing effect as a stiffener connecting the coupling end face portions of the transaxle at the rear end of the engine body ( Enlarged sectionThis also works to the advantage of the reinforcing effect.

[0023] Improving vibration and noise quality requires increasing the rigidity of the powertrain system against bending and torsion to raise the resonant frequency. However, increasing rigidity through reinforcement to improve the resonant frequency also leads to an increase in weight, so balancing these two factors is crucial. Therefore, simply reinforcing does not necessarily lead to an improvement in the resonant frequency, which presents a challenge.

[0024] In this regard, the structure of the present invention solves the disadvantages of increased weight of electric auxiliary equipment and increased weight of the transaxle due to hybridization by changing the layout of auxiliary equipment components, reinforcing the engine body with auxiliary equipment mounting brackets, and providing a stiffening effect to the brackets to improve the rigidity of the connection between the engine body and the transaxle, thereby achieving an improvement in the resonant frequency while suppressing the increase in weight.

[0025] Furthermore, the engine body is shared between hybrid and non-hybrid vehicles. When used in a hybrid vehicle, the bracket is fixed, and when used in a non-hybrid vehicle, the bracket is fixed. of It is also possible to choose not to use it at all. This allows for the sharing of the engine body between engines with different specifications, contributing to overall cost reduction. Alternatively, the engine body for non-hybrid vehicles can be easily repurposed for hybrid vehicles. [Brief explanation of the drawing]

[0026] [Figure 1] (A) is a schematic side view of the powertrain without the bracket attached, and (B) is a side view of the main part of the powertrain according to the embodiment. [Figure 2] This is a perspective view of the powertrain without the bracket installed. [Figure 3] This is a side view of the main part with the bracket attached. [Figure 4]This is a perspective view of the main parts with the bracket attached. [Figure 5] This is a side view of the main components with the air conditioner compressor installed. [Figure 6] This is a partial perspective view of the air conditioner with the compressor installed. [Modes for carrying out the invention]

[0027] Next, embodiments of the present invention will be described based on the drawings. This embodiment is applied to a 3-cylinder engine, and the engine is positioned in the engine compartment with the crankshaft in a position that is elongated in the vehicle width direction and the exhaust side facing forward. Therefore, it is a transversely mounted, front-exhaust (rear-intake) type.

[0028] In this embodiment, the terms "front / rear" and "left / right" are used to specify directions. The front / rear direction is the direction of the crank axis, and the left / right direction is the direction perpendicular to the crank axis and cylinder bore axis. Therefore, the angle differs by 90° from the front / rear direction of the vehicle body. The front and rear are defined as the side where the timing chain is located and the rear as the side where the transaxle is located. The front view is the view from front to rear, and the side view is the view from the left or right.

[0029] (1) Overview Figure 1(A) schematically shows the entire powertrain. In Figure 1(A), the powertrain is viewed from the exhaust side, and the powertrain is broadly composed of the engine body 1 and the transaxle 2.

[0030] The engine body 1 comprises a cylinder block 3 and a cylinder head 4 fixed to its upper surface, an oil pan 5 fixed to the lower surface of the cylinder block 3, a front cover (chain cover) 6 fixed to the front of the cylinder block 3 and cylinder head 4, and a head cover 7 fixed to the upper surface of the cylinder head 4. The timing chain is located in the space enclosed by the front cover 6 and the cylinder block 3 and cylinder head 4.

[0031] A single exhaust outlet hole is located on the exhaust side of the cylinder head 4, to which a catalytic converter case 8, containing an exhaust gas purification catalyst, is connected. The catalytic converter case 8 is positioned roughly in the middle of the exhaust side. In some cases, an exhaust turbocharger is connected to the exhaust outlet hole, and the catalytic converter case 8 is connected to the exhaust turbocharger. The exhaust pipe (not shown) connected to the catalytic converter case 8 is routed backward from the recessed portion 5a of the oil pan 5. An oil filter 9 is mounted on the underside of the front cover 6.

[0032] The transaxle 2 consists of a housing section 10 that houses a flywheel or drive plate and torque converter, fixed to the rear surface of the cylinder block 3 and oil pan 5 with a group of bolts, and a transaxle main body section that is based on an oil-lubricated environment and incorporates a motor generator and power transmission mechanism, fastened (flange-jointed) to the rear surface of the housing section 10 with a group of bolts. In this embodiment, the differential mechanism is built into the space formed at the mating surface between the housing section 10 and the transaxle main body section.

[0033] A Power Control Unit (PCU) 12 is mounted on top of the transaxle 2, which is responsible for controlling the motor-generator's output, power generation, battery charging and discharging, and regenerative braking during deceleration.

[0034] In this embodiment, the mass of the transaxle 2 is greater than the mass of the engine body 1. Therefore, the center of gravity G of the powertrain is located on the side of the transaxle 2.

[0035] The powertrain is supported by the vehicle body via three mounts: a right mount 13a, a left mount 13b, and a rear mount (torque rod) 13c. The right mount 13a is located on the front of the upper end of the front cover 6, and the left mount 13b is located on the rear of the upper end of the second transmission case 11. The rear mount 13c is located at the lower end of the housing portion 10.

[0036] (2).Details Next, with reference to the drawings starting from Figure 1(B), the details of the engine body 1 will be explained. Figures 1(B) to 6 show the engine body 1 as viewed from the intake side. For example, as can be easily understood from Figures 2 and 4, a rear flange 15a (transaxle coupling end face) is formed on the rear surface of the cylinder block 3, and the front flange 15b of the housing portion 10 is fixed to the rear flange 15a with a group of bolts 17.

[0037] As can be easily understood from Figures 2 and 4, the housing portion 10 is sized to accommodate the flywheels, and therefore the rear of the cylinder block 3 is conical in shape toward the housing portion 10. (To the left and right, outwards) spread Enlarged section 3a It has become so Enlarged section 3a outer periphery (rear end) A rear flange 15a is formed thereon. Enlarged section 3a The rear flange 15a (and the rear flange 15a) is reinforced from both sides (exhaust side and intake side) by ribs 16.

[0038] Furthermore, in the cylinder block 3 of the non-hybrid engine, the transmission is positioned opposite it. So, Aflange to, Mounting holes for the starter motor, which is mounted along the intake side wall of the block, were formed, but in hybrid vehicles, the transaxle is located inside Motor Generator In order for it to perform that function, the cylinder block 3 of this embodiment Enlarged section 3a It is formed to bulge out radially in a continuous and uninterrupted manner, and the structure allows for the installation of additional fastening points that serve as reinforcing parts (stiffener shape) while the electrically operated auxiliary equipment mounting bracket, described later, smoothly overlaps with the rear flange 15a (transaxle coupling end face).

[0039] As shown in Figures 1(B) and 1(2), the oil pan 5 is fixed to the cylinder block 3 by a group of bolts 5b. Similarly, as shown in Figures 1(B) and 1(2), the front cover 6 is fixed to the cylinder block 3 and cylinder head 4 by a group of bolts 6a.

[0040] For example, as shown in Figure 2, a crank torsion damper 18 is positioned on the front of the front cover 6. The crank torsion damper 18 is fixed to the front end face of the crankshaft by bolts 19. In non-hybrid engines, the crank torsion damper 18 is a crank pulley with a belt groove that drives, for example, the water pump or alternator. However, in hybrid vehicle engines, an electric water pump is used, and power generation is performed by a motor generator built into the transaxle, so there is no alternator. Therefore, the crank torsion damper 18 functions only as a torsion damper. Figures 2 and 4 show the cylinder bore 20, water jacket 21, and right mount support 22.

[0041] As shown in Figures 1(B) and 2, an oil separator chamber 23 is formed in the upper part of the intake side of the cylinder block 3 to collect oil mist from blow-by gas that has blown into the crankcase. The oil separator chamber 23 is covered by a cover plate 24, and a PCV outlet port 25 is opened in the cover plate 24. A PCV valve is installed in the PCV outlet port 25.

[0042] Furthermore, as shown in Figures 3 and 4, a reinforcing bracket (stiffener) 26 is positioned on the intake side of the cylinder block 3 so as to cover a corresponding portion of the intake side, and the bracket 26 is fixed to the cylinder block 3 with bolts 27 to 32 numbered 1 to 6. The bracket 26 is designed so as not to interfere with the PCV valve installed in the PCV outlet port 25. The bracket 26 is made of cast or die-cast material, but sheet metal parts can also be used.

[0043] The bracket 26 has a roughly pentagonal shape in side view, with its front-to-back length slightly longer than its height, and an outward-facing peripheral wall 33 is formed around the bottom plate. Therefore, the bracket 26 has a tray-like shape. In addition, a group of ribs 34 and 35 are formed inside. Furthermore, a rear boss portion 36 is formed at the rear end of the bracket 26, which overlaps the housing portion 10, and the rear boss portion 36 is fixed to the housing portion 10 with a seventh bolt 37.

[0044] Therefore, the rear boss portion 36 is formed to straddle the rear flange 15a of the cylinder block 3 from the outside, and as can be easily understood from Figure 2, the housing portion 10 has a receiving portion 38 that protrudes to the outside of the flanges 15a and 15b, and a tapped hole 39 into which the seventh bolt 37 is screwed is formed in the receiving portion 38.

[0045] Furthermore, it is also possible to bolt the rear end of the bracket 26 and the rear flange 15a of the cylinder block 3 together to the housing portion 10. In addition, although the boss portion 36 straddles the front flange 15b of the housing portion 10 in the illustrated configuration, it is also possible to overlap and fix the boss portion 36 to the front end surface of the front flange 15b (in this case, an outward-facing bulge is formed on the front flange 15b that overlaps with the boss portion 36).

[0046] Regarding the arrangement of the first to seventh bolts 27-32 and 37, as shown in Figure 3, the first to third bolts 27-29 are arranged in a front-to-back direction on the upper edge of the bracket 26, and the fourth to sixth bolts 30-32 are arranged in a front-to-back direction on the lower edge of the bracket 26. The seventh bolt 37 is positioned higher than the sixth bolt 32. Thus, the seven bolts 27-32 and 37 are arranged in a well-balanced manner both vertically and horizontally. Furthermore, the first to sixth bolts 27-32 are distributed and fixed to the high-rigidity parts of the cylinder block 3 (on the block reinforcing ribs set near the oil pan rail and cylinder head connection).

[0047] As shown in Figures 5 and 6, an air conditioning compressor 47, as an example of an electric auxiliary device, is fixed to the bracket 26 by a group of bolts 48. The air conditioning compressor 47 is positioned so as to partially overlap the front cover 6 in a side view, but it does not protrude in front of the front cover 6.

[0048] The air conditioner compressor 47 has a roughly rectangular shape when viewed from the side, with the front-to-back length being the longest part, and is fixed at two points each on its top and bottom edges with bolts 48. For this reason, as shown in Figures 3 and 4, the bracket 26 is provided with boss portions 49 having tapped holes into which the bolts 48 are screwed. For fixing the compressor The boss portion 49 is integrally connected to the peripheral wall 33 of the bracket 26. There are two types: one located on the outer periphery, and another located inside the bracket 26.

[0049] The bracket 26 has the previously described ribs 34 and 35 formed inside, which are the boss portion where the fifth bolt 31 is formed. 26a,49 Ribs 34 extending radially from the air conditioner compressor 47 Outer perimeter It is composed of a single radial rib 34 and an inclined rib 35 connecting the boss portion 49. 1 The inclined ribs 35 intersect in an X-shape.

[0050] (3) Summary Now, as shown in Figure 1(A), the powertrain is suspended by the right mount 13a and the left mount 13b, so the fastening rigidity between the rear flange 15a, which is located in the center of the span of the powertrain structure composed of the engine 1 and the transaxle 2, and the housing portion 10 is important. In this embodiment, bracket 26 teeth, It functions as a stiffener to improve the joint rigidity of the relevant part of the powertrain system, which has become heavier compared to non-hybrid engines, and also functions effectively as a reinforcing member for the cylinder block, which has become relatively less rigid due to the increased weight.

[0051] Because the air conditioning compressor 47 is quite heavy, the conventional mounting position, which is based on belt drive, generates a large inertial force when the powertrain vibrates, increasing the vibration of the powertrain. In contrast, as in this embodiment, by setting the air conditioning compressor 47 so that it does not protrude from the front surface of the front cover 6, the kinetic energy due to the vibration of the air conditioning compressor 47 can be suppressed, and thus the vibration of the powertrain can also be suppressed (the resonant frequency is improved).

[0052] Furthermore, by positioning the air conditioning compressor closer to the powertrain's center of gravity, the vibration G acting on it due to powertrain vibrations can be reduced, thus offsetting the increased vibration caused by the increased weight of the motor due to electrification (and thus improving the durability and reliability of the mounted auxiliary equipment).

[0053] Furthermore, in this embodiment, a catalytic converter case 8 is positioned on the exhaust side of the cylinder block 3, and an air conditioning compressor 47 is positioned on the intake side. Since the catalytic converter case 8 also has considerable mass, the catalytic converter case 8 and the air conditioning compressor 47 can balance the left and right sides. Therefore, torsional forces acting on the engine body 1 can be suppressed, as can wobble movements around the axis of the crankshaft.

[0054] In this embodiment, the air conditioning compressor 47 is fixed to the bracket 26, and the bracket 26 is directly fixed to the cylinder block 3. With this configuration, the cylinder block 3 can be easily used for both engines that do not use the bracket 26 and engines that do use the bracket 26. Therefore, overall costs can be reduced when preparing hybrid and non-hybrid engines. In addition, it is easy to apply the cylinder block 3 of an existing non-hybrid engine to a hybrid engine without requiring major design changes.

[0055] An intake manifold is fixed to the intake side of the cylinder head 4, but in this embodiment, the dead space below the intake manifold can be effectively utilized as space for the air conditioning compressor 47. Therefore, even in cases where the engine compartment is small, such as in a kei car, the air conditioning compressor 47 can be efficiently positioned.

[0056] The embodiments of the present invention have been described above, but the present invention can be implemented in various other ways. For example, the number of engine cylinders can be set arbitrarily. The bracket can also be configured in a way that suits the size of the powertrain, for example, by fixing it to the transaxle at multiple points to improve its function as a stiffener that enhances the rigidity of the powertrain. A supercharger can also be used as an electric auxiliary device. [Industrial applicability]

[0057] The present invention can be implemented in a powertrain for a hybrid vehicle. Therefore, it is industrially applicable. [Explanation of symbols]

[0058] 1. Engine body 2 transaxles 3 Cylinder block 3a Enlarged section 4 Cylinder head 5 Oil pan 6. Front cover (chain cover) 8 Catalyst Case 10 Housing section 11 transaxle 12 PCU 13a~13c mount 15a Rear flange of cylinder block 15b Front flange of the housing 23 Oil Separator Room 25 PCV output ports 26 brackets 26a Boss portion for fixing the bracket 27-32 Bolts for fixing the bracket 34. Radial Ribs 35 Ribs in an inclined position 36 Rear boss section 37 Bolts for fastening the bracket to the transaxle. 47. Air conditioning compressor as an example of an electric auxiliary device 49 Boss section for fixing the compressor

Claims

1. The engine body comprises a cylinder block, a cylinder head, an oil pan, and a head cover; a transaxle fixed to one end face of the engine body facing the crank axis; and a bracket positioned on one side of the engine body facing left and right perpendicular to the crank axis and cylinder bore axis, to which an electric auxiliary device is attached. The engine body has a portion at one end to which the transaxle is attached and located on one side, which is formed as an enlarged portion that extends outward in the left-right direction toward the transaxle, and the enlarged portion is bolted to the transaxle in this powertrain. The bracket is formed in the shape of a tray having a peripheral wall, and inside it is formed a boss portion and a group of ribs extending radially from the boss portion and connected to the peripheral wall. The bracket is positioned so as to partially overlap with the enlarged portion of the engine body. The powertrain of a hybrid vehicle.

2. The outer circumference of the bracket is formed with a group of outer circumference bosses for fixing the electric auxiliary equipment, two of the outer circumference bosses are connected by an inclined rib, and the inclined rib and the radially extending rib intersect. The powertrain of the hybrid vehicle described in claim 1.

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