Range extender for battery electric vehicle

Abstract

To provide a range extender for a motor vehicle which enables reduction of vibration occurring therein.SOLUTION: A range extender 1 for a battery electric vehicle (BEV) comprises: a two-cylinder horizontally opposed engine 2 dedicated to power generation; a generator 3; a fuel tank 4 for the engine 2 dedicated to power generation; and a cooling device 8 for the engine 2 dedicated to power generation. The engine 2 dedicated to power generation includes: a crankshaft 11 having a horizontal rotation center axis line; two cylinders 12 arranged facing each other across the crankshaft 11; and pistons 13 arranged in the cylinders 12 so as to face each other across the crankshaft 11. The generator 3 is arranged at an approximately central part in a longitudinal direction of the engine 2 dedicated to power generation so that the engine 2 dedicated to power generation and the generator 3 form a T-shape in a plan view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a range extender for a battery electric vehicle that is mounted on a battery electric vehicle having four or more wheels to extend the driving range.

[0002] In this specification and claims, the left and right sides of Figures 1 and 4 will be referred to as left and right, and the top and bottom sides of Figures 2 and 3 will be referred to as top and bottom. Additionally, the top side of Figures 1 and 4 (the left side of Figure 2) will be referred to as the front, and the opposite side will be referred to as the rear. [Background technology]

[0003] Battery electric vehicles (hereinafter sometimes referred to as BEVs), which are equipped with a battery and run only on a traction motor powered by the battery, are rapidly becoming popular in major developed markets around the world. BEVs are automobiles equipped with a battery and a traction motor powered by the battery, and various types of BEVs have been developed, such as passenger cars, SUVs (sports utility vehicles), pickup trucks, and van-type trucks. However, all types of BEVs share the common problem of a short driving range and a relatively long time required to charge the battery, due to the issue of the energy capacity of the battery that can be installed.

[0004] In order to solve such problems, various range extenders for BEVs have been proposed. For example, Patent Document 1 discloses a range extender for BEVs that includes a generator engine, a generator that generates electricity by driving the generator engine, a fuel tank for the generator engine, and a cooling device for the generator engine, and includes a crankcase incorporating a crankshaft arranged so that its central axis of rotation is horizontal with its longitudinal direction facing the vehicle width direction, a cylinder case incorporating a cylinder arranged only on one side of the crankshaft so that its axial direction is perpendicular to the vehicle width direction, and a piston that is driven within the cylinder in a direction perpendicular to the vehicle width direction, and the generator is arranged at one end of the crankcase in the longitudinal direction so as to be aligned in a straight line with the crankcase. The crankcase is placed in a cylinder case, the cooling device is arranged at the other longitudinal end of the crankcase so as to be aligned in a straight line with the crankcase, the rotating shaft of the generator is connected to the crankshaft, the combination consisting of the crankcase, generator and cooling device and the cylinder case are T-shaped in a plan view, and the fuel tank is arranged in one of the spaces surrounded by the vertical plane in which the end of the cooling device opposite the crankcase is located and the vertical plane in which the end of the generator engine opposite the crankcase is located, with part of the fuel tank extending outside the space. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-72237 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the BEV range extender described in Patent Document 1, the crankshaft of the generator engine faces the vehicle width direction, the cylinder is arranged on only one side of the crankshaft with the axis facing the vehicle width direction, and the piston is driven in the cylinder in the direction perpendicular to the vehicle width direction, so that the generator engine is an in-line engine and generates relatively large vibrations, which results in the relatively large vibrations being transmitted to the passengers.

[0007] The object of the present invention is to provide a range extender for a BEV that can solve the above problems, reduce the vibration generated, and comply with automobile exhaust gas regulations and automobile crash safety standards so that it can be used in various BEVs with different body structures and sizes. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention comprises the following aspects.

[0009] 1) A range extender for a battery electric vehicle, which is equipped with a generator, a generator that generates electricity by driving the generator, a fuel tank for the generator, and a cooling device for the generator, and which supplies power to the drive battery of the battery electric vehicle, The power generation engine is a horizontally opposed two-, four- or six-cylinder engine, and includes a crankshaft whose central axis of rotation is horizontal, an even number of cylinders arranged opposite each other across the crankshaft, and pistons arranged in each cylinder so as to face each other across the crankshaft. The cylinders are arranged on both the left and right sides of the crankshaft with their longitudinal directions facing left and right. The generator is arranged approximately in the center of the length of the power generation engine so that the power generation engine and the generator are T-shaped in a plan view. The rotating shaft of the generator is arranged horizontally on the same axis as the crankshaft or on an axis parallel to the crankshaft and is connected to the crankshaft via a transmission. As the crankshaft rotates, the generator is rotated at an increased or decreased speed via the transmission. And, The engine for generating electricity comprises a cylinder block in which cylinders are formed with their longitudinal directions oriented in the left-right direction, a cylinder head in which combustion chambers are formed corresponding to each cylinder and in which two intake ports and two exhaust ports facing the combustion chambers are formed, two intake valves which open and close both intake ports of each combustion chamber, two exhaust valves which open and close both exhaust ports of each combustion chamber, and a valve mechanism which opens and closes all intake valves and all exhaust valves, the valve mechanism being composed of a first valve unit which opens and closes all intake valves and a second valve unit which opens and closes all exhaust valves, Two intake ports are formed in a row in front of and behind the upper portion of the combustion chamber, and two intake valves are arranged in a row in front of and behind the upper portion of the combustion chamber, two exhaust ports are formed in a row in front of and behind the lower portion of the combustion chamber, and two exhaust valves are arranged in a row in front of and behind the lower portion of the combustion chamber, and the two intake valves are arranged above the two exhaust valves, the first valve train unit is provided with a first camshaft disposed at a height position above the cylinders and directly above the crankshaft, and rotated by the crankshaft about a horizontal rotational center axis, two first push rods provided for each cylinder and driven by cams of the first camshaft, and two first rocker arms provided for each cylinder and driven by the first push rods, and transmits input by the cams of the first camshaft to the intake valves of all the cylinders; The second valve train unit includes a second camshaft that is disposed at a height below the cylinder and directly below the crankshaft and is rotated by the crankshaft about a horizontal rotation center axis, two second push rods provided for each cylinder and driven by cams of the second camshaft, and two second rocker arms provided for each cylinder and driven by the second push rods, and transmits input from the cams of the second camshaft to all exhaust valves. A range extender for battery electric vehicles.

[0010] 2) A range extender for a battery electric vehicle as described in 1) above, wherein the generator-only engine is provided with an intake manifold that has a surge tank and a branch pipe in its intake air path and supplies intake air to an intake port provided in the cylinder head, and the surge tank of the intake manifold is arranged along the side of the generator-only engine opposite to the side where the generator is located, and / or along a portion of the top surface of the generator-only engine opposite to the side where the generator is located.

[0011] 3) A range extender for a battery electric vehicle as described in 2) above, wherein a tip of the branch pipe of the intake manifold is connected to an upper surface of the cylinder head of the generator-only engine.

[0012] 4) A range extender for a battery electric vehicle as described in 2) above, wherein the generator-only engine is a horizontally opposed two-cylinder engine with one cylinder on each side of the crankshaft, i.e., two cylinders on the left and right, and the tip of a branch pipe of the intake manifold is connected to the side of the cylinder head of the generator-only engine.

[0013] 5) The range extender for a battery electric vehicle described in 1) above, wherein the fuel tank is arranged so that the entire fuel tank is contained within at least one of the two spaces surrounded by the vertical plane on which both longitudinal ends of the generator-only engine are located and the vertical plane on which the tip of the generator protruding from the generator-only engine is located.

[0014] 6) A range expander for a battery electric vehicle as described in 1) above, in which the fuel tank is entirely disposed within one of two spaces surrounded by a vertical plane on which both longitudinal ends of the generator-only engine are located and a vertical plane on which the tip of the generator protruding from the generator-only engine is located, and the cooling device is at least partially disposed within the other space. Stender . Effect of the Invention

[0015] 1) above~ 6) The range extender for BEVs uses a horizontally opposed two-, four-, or six-cylinder engine dedicated to generating electricity, so the vibrations generated are relatively small and the vibrations transmitted to the occupants are also relatively small.

[0016] In addition, the generator is disposed in the center of the length of the generator engine so that the generator and the generator are T-shaped in plan view, and two spaces are formed between both ends of the generator engine in the length direction and the tip of the generator protruding from the generator engine. The two spaces, which are safe even in the event of a collision, created by the rigid generator engine and the rigid generator can be effectively used as the entire fuel tank, part of the cooling device for the generator engine, and installation space for an inverter, etc. As a result, even if the vehicle has a completely different body structure, such as a monocoque structure, which is the mainstream structure of passenger cars, or a ladder frame structure, which is the mainstream structure of commercial trucks and pickup trucks, it can be mounted without the need for a special vehicle frame or a protective frame for safety, and the requirements for a power generation unit for various BEVs can be achieved, such as miniaturization, compactness, and weight reduction.

[0017] Furthermore, because the power generation engine and generator are arranged as described above, the area of ​​the mount used when mounting the power generation engine and generator on the vehicle body can be made larger, making it easier to absorb the rotational moment generated by the power generation engine and generator, and reducing its transmission to the vehicle body.

[0018] Furthermore, according to the BEV range extender mentioned in 1) above, in order to ensure a high combustion level, it is essential that the values ​​and ratios of the combustion chamber bore and stroke, the number, shape and position of the intake and exhaust ports, and the position of the spark plug are similar to the layout of DOHC 4-valve engines in existing passenger cars that have already complied with automobile exhaust gas regulations, which are factors that roughly determine the basic combustion and basic exhaust gas components that comply with automobile exhaust gas regulations. Within this, the essential conditions for the valve train are that each cylinder has two intake ports and two intake valves, two exhaust ports and two exhaust valves, a straight port shape and position, and centrally located spark plugs.

[0019] In addition, in order to achieve the small, compact, and lightweight design required for a dedicated power generation engine for BEV range extenders, power generation operation at high speeds, which transmits relatively large vibrations to passengers, is suppressed and can be compensated for by operation at medium speeds or slower, so the high-speed rotating elements of the valve train are omitted, resulting in a small, compact, and lightweight design.

[0020] Specifically, the two intake valves that open and close the two intake ports are operated by a first rocker arm, a first pushrod, and a first camshaft of a first valve train unit that is disposed in the cylinder head and the cylinder case, and the two exhaust valves that open and close the two exhaust ports are operated by a second rocker arm, a second pushrod, and a second camshaft of a second valve train unit that is disposed in the cylinder head and the cylinder case. As a result, two camshafts can be omitted from each of the left and right cylinder heads, i.e., a total of four camshafts can be omitted from the left and right cylinder heads, and two cam sprockets (four in total) of the valve train drive system that drives each camshaft can also be omitted. As a result, the amount of lubricating oil required in the cylinder head can be reduced, and the range extender as a whole can be made smaller, more compact, and lighter. At the same time, costs can be reduced. As a result, it is possible to provide a small, compact, range extender-only power generation engine that has less vibration while maintaining a combustion level similar to that of existing DOHC engines and clearing automobile exhaust gas regulations. .

[0021] According to the BEV range extenders of 2) and 3) above, the surge tank of the intake manifold is positioned along the side of the power generation engine opposite the side where the generator is located and / or along the portion of the top surface of the power generation engine opposite the side where the generator is located, so that the vertical dimension of the BEV range extender can be made relatively small, thereby making it possible to reduce the installation space required for the BEV.

[0022] When a horizontally opposed 2-, 4- or 6-cylinder engine is used to directly drive a vehicle, in order to improve output from idle speed through the normal speed range and even at the maximum allowable speed, it is necessary to reduce the passage resistance from the intake manifold to the intake ports inside the engine's cylinder head; therefore, the only structure that can be used for the intake manifold is one that rises vertically from the cylinder head, connects the left and right sides on the cylinder line, with a chamber in the center.

[0023] In contrast, in the case of a generator-only engine for a BEV range extender, while it is essential to ensure basic combustion and exhaust gas performance that meets automobile exhaust gas regulations, the generator operation at high revolutions, when relatively large vibrations are transmitted to the occupants, can be suppressed and compensated for by generating electricity at mid-speed or lower revolutions. As a result, the intake manifold does not need to be shaped so that it rises vertically from the cylinder head, and it can be arranged at an angle or bent from directly above the cylinder head. In other words, the intake manifolds in 2) and 3) above fall into this category.

[0024] Furthermore, by improving the intake system as described in 2) and 3) above, it is possible to reduce the height dimension of the intake system even when using a horizontally opposed engine, which basically has little vibration, and it is possible to reduce the vertical dimension of the BEV range extender. As a result, it can be placed in any suitable position according to the various body structures and sizes of the BEV. Specifically, it can be installed in BEVs of different body structures and sizes, such as passenger cars, SUVs, pickup trucks, and van-type trucks.

[0025] According to the BEV range extender of 4) above, the generator-only engine is a horizontally opposed two-cylinder engine with one cylinder on each side of the crankshaft, i.e., two cylinders on the left and right, and the tip of the branch pipe of the intake manifold is connected to the side of the cylinder head of the generator-only engine. Therefore, the protruding height of the intake manifold from the top surface of the generator-only engine can be made even lower than that of the BEV range extenders of 2) and 3) above. can . [Brief description of the drawings]

[0026] [Figure 1] 1 is a schematic plan view showing a range extender for a BEV according to the present invention; [Diagram 2] FIG. 2 is a schematic side view of the range extender for the BEV of FIG. 1. [Diagram 3] FIG. 2 is a schematic front view of the BEV range extender of FIG. 1. [Figure 4] 1 is a schematic plan view showing a range extender for a BEV according to the present invention with the intake manifold omitted. [Diagram 5] 2 is a front view showing a schematic configuration of a portion of the power generation engine of the BEV range extender of FIG. 1. [Figure 6] FIG. 2 is a perspective view showing a valve train of a generator-only engine of the BEV range extender of FIG. 1. [Figure 7] FIG. 2 is a front view showing a valve train of a power generation engine of the BEV range extender of FIG. [Figure 8] 2 is a plan view showing a valve train of a power generation engine of the BEV range extender of FIG. 1. [Figure 9] 1 is a front view showing a modified example of an intake manifold used in a power generation engine of a BEV range extender according to the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0028] In the following description, the left and right sides of Figures 1 and 4 will be referred to as left and right, and the top and bottom sides of Figures 2 and 3 will be referred to as top and bottom. Additionally, the top side of Figures 1 and 4 (the left side of Figure 2) will be referred to as the front, and the opposite side will be referred to as the rear.

[0029] In the following description, the same items and parts are given the same reference numerals.

[0030] Figures 1 to 4 show a schematic diagram of the overall configuration of a BEV range extender with some parts omitted. Also, Figure 5 shows a schematic diagram of a portion of the configuration of the generator-only engine of the BEV range extender, and Figures 6 to 8 show the valve train of the generator-only engine of the BEV range extender.

[0031] In Figures 1 to 5, the BEV range extender (1) includes a generator (2) for generating electricity, a generator (3) that generates electricity by driving the generator-only engine (2), a fuel tank (4) for the generator-only engine (2), a cooling device (5) for the generator-only engine (2), and a mount (not shown) used when installing the BEV range extender (1) in an automobile.

[0032] Although not shown in the figure, the BEV range extender (1) is equipped with electrical equipment necessary for generating power, such as an inverter.

[0033] The power-generating engine (2) is a horizontally opposed engine that includes a crankshaft (11) having a horizontal central axis of rotation extending in the front-to-rear direction, an even number of cylinders (12) (two in this embodiment) arranged on both left and right sides of the crankshaft (11) so as to face each other with the crankshaft (11) in between, pistons (13) arranged in each cylinder (12) so as to face each other on both left and right sides of the crankshaft (11) with the crankshaft (11) in between, and an intake manifold (14). The cylinders (12) are arranged in equal numbers on both left and right sides of the crankshaft (11) with their longitudinal directions facing in the left-right direction.

[0034] The power-generating engine (2) includes two cylinder blocks (15) (left and right) and a cylinder head (16), and the crankshaft (11) is supported rotatably by both cylinder blocks (15) while being sandwiched between them. The two pistons (13) (left and right) are connected to the crankshaft (11) via connecting rods (13a), respectively, and the crankshaft (11) is rotated about the central axis of rotation by the reciprocating motion of both pistons (13). The cylinder block (15) and the cylinder head (16) may be formed separately and fixed to each other, or may be formed integrally.

[0035] Each cylinder block (15) of the power-generating engine (2) is formed with one cylinder (12), and each cylinder head (16) is formed with one combustion chamber (17) corresponding to the cylinder (12), and two intake ports (18) and two exhaust ports (19) facing the combustion chamber (17). The two intake ports (18) of each cylinder head (16) are opened and closed by an intake valve (21), and the two exhaust ports (19) are opened and closed by an exhaust valve (22). The two intake ports (18) are formed in the upper part of the combustion chamber (17) side by side, and two intake valves (21) for opening and closing the two intake ports (18) are arranged in the front and rear side. In addition, two exhaust ports (19) are formed in the lower part of the combustion chamber (17) side by side, and two exhaust valves (22) are arranged in the front and rear side. The two intake valves (21) are arranged above the two exhaust valves (22). That is, the power generation engine (2) has two cylinders (12) and two combustion chambers (17), four intake ports (18) and four exhaust ports (19), as well as four intake valves (21) and four exhaust valves (22).

[0036] 5 to 8, the intake valves (21) that open and close the four intake ports (18) and the exhaust valves (22) that open and close the four exhaust ports (19) are operated by a valve mechanism (23). The valve mechanism (23) is composed of a first valve unit (24) that operates all the intake valves (21) that open and close both the intake ports (18) facing the left and right combustion chambers (17), and a second valve unit (25) that operates all the exhaust valves (22) that open and close both the exhaust ports (19) facing the left and right combustion chambers (17). The first valve train unit (24) includes a first camshaft (26) that is disposed at a height position above the cylinders (12) and directly above the crankshaft (11) and is rotated by the crankshaft (11) around a horizontal central axis of rotation, two first push rods (28) provided for each cylinder (12) and driven by two first cams (27) attached to the first camshaft (26), two on each side (left and right), a total of four, and two first rocker arms (29) provided for each cylinder (12) and driven by the first push rods (28), two on each side (left and right), a total of four, and transmits input by the first cams (27) of the first camshaft (26) to all the intake valves (21). The first camshaft (26) is disposed at a height position above both cylinders (12) and directly above the crankshaft (11). The second valve train unit (25) includes a second camshaft (31) that is disposed at a height below the cylinders (12) and immediately below the crankshaft (11) and that is rotated by the crankshaft (11) around a horizontal central axis of rotation, two second push rods (33) provided for each cylinder (12) and driven by two second cams (32) attached to the second camshaft (31), two second rocker arms (31) provided for each cylinder (12) and driven by the second push rods (33), two second rocker arms (31) provided for each cylinder (12) and driven by the second push rods (33), two second rocker arms (31) provided for each cylinder (12) and driven by the second push rods (33), and transmits the input from the second camshaft (27) to all exhaust valves (22). The second camshaft (31) is disposed at a height below both cylinders (11) and immediately below the crankshaft (11).

[0037] The number of intake ports and intake valves, and the number of exhaust ports and exhaust valves are not limited to 2. Furthermore, the valve train that operates the intake valves and exhaust valves is not limited to the above, and it is possible to use a known SOHC (single overhead cam) type, DOHC (double overhead cam) type, or OHV (overhead valve) type.

[0038] 1 and 4, the generator (3) is disposed at approximately the center in the longitudinal direction of the power-generator engine (2) such that the power-generator engine (2) and the generator (3) form a T-shape in a plan view. The rotating shaft (3a) of the generator (3) is disposed horizontally on the same axis as the crankshaft (11) or on an axis parallel to the crankshaft (11) and is connected to the crankshaft (11) via a transmission device (35). The generator (3) is rotated at an increased or decreased speed by the rotation of the crankshaft (11).

[0039] The fuel tank (4) is arranged so that the entirety fits within at least one of the two spaces (36), (37) surrounded by the vertical plane on which both longitudinal ends of the generator-only engine (2) are located and the vertical plane on which the tip of the generator (3) protruding from the generator-only engine (2) is located, in this case the right-side space (36). The location of the fuel tank (4) is not limited thereto and can be changed as appropriate.

[0040] The cooling device (5) is disposed so that at least a part of it fits in the left space (37) in this case, opposite the right space (36) in which the fuel tank (4) is disposed, of two spaces (36) and (37) surrounded by a vertical plane on which both ends of the generator-only engine (2) in the longitudinal direction are located and a vertical plane on which the tip of the generator (3) protruding from the generator-only engine (2) is located. The location of the cooling device (5) is not limited thereto and can be changed as appropriate. For example, the cooling device (5) may be disposed in parallel with the longitudinal direction of the generator-only engine (2) on the front side of the generator-only engine (2) of the BEV range extender (1) opposite the side on which the generator (3) is disposed.

[0041] Furthermore, electrical equipment required for power generation, such as an inverter, may be placed in the spaces (36) and (37).

[0042] The intake manifold (14) has a surge tank (38) and branch pipes (39) in the same number as the cylinders (12). The surge tank (38) of the intake manifold (14) is disposed along the front portion of the upper surface from the front side of the generator-only engine (2) opposite the side where the generator (3) is disposed. The branch pipes (39) extend in the left-right direction from the surge tank (38) and have their ends connected to the upper surface of the cylinder head (16) of the generator-only engine (2). The left branch pipe (39) feeds intake air to the intake port (21) facing the left combustion chamber (17), and the right branch pipe (39) feeds intake air to the intake port (21) facing the right combustion chamber (17).

[0043] The above-mentioned BEV range extender (1) is installed in various locations in the BEV.

[0044] For example, in the case of a pickup truck, the BEV range extender (1) is located under the engine compartment or below the cargo bed. In the case of a van-type truck, the BEV range extender (1) is located below the cargo compartment. In the case of a passenger car, the BEV range extender (1) is located under the engine compartment or below the trunk. In the case of an SUV (sports utility vehicle), the BEV range extender (1) is located under the engine compartment or below the cargo compartment.

[0045] These are merely examples, and the installation location of the automotive range extender (1) is not limited to those shown in the drawings, and the range extender can be installed anywhere as long as the necessary space can be secured.

[0046] When the remaining charge of the drive battery of the BEV equipped with the BEV range extender (1) becomes low, the power generation engine (2) is driven to generate electricity using the generator (3), and the generated electricity is supplied to the drive battery of the BEV, thereby extending the driving range of the BEV.

[0047] In the above-described embodiment, the surge tank (38) of the intake manifold (14) is disposed along the front portion of the upper surface from the front side surface of the power-generation-only engine (2) opposite the side on which the generator (3) is disposed, but this is not limited to this.

[0048] 9, the generator-only engine (2) may include a surge tank (41) disposed along the front side of the generator-only engine (2) and an intake manifold (40) including left and right branch pipes (42) extending in the left-right direction from the surge tank (41) and having their ends connected to the front side of the cylinder head (16) of the generator-only engine (2). The left branch pipe (42) feeds intake air to the intake port (21) facing the left combustion chamber (17), and the right branch pipe (42) feeds intake air to the intake port (21) facing the right combustion chamber (17).

[0049] In the above-described embodiment, the power-generation engine (2) is a horizontally opposed engine having two cylinders (12), but the present invention is not limited thereto, and may be a horizontally opposed engine having four cylinders or a horizontally opposed engine having six cylinders. In these cases, the end of the branch pipe of the intake manifold used in the power-generation engine is connected to the upper surface of the cylinder head (16). In these cases, the same even number of cylinders are arranged on both sides of the crankshaft (11), and the cylinders on both sides of the crankshaft (11) are formed in one cylinder block, and one cylinder head is attached to the cylinder block. In the cylinder head, combustion chambers corresponding to the cylinders, two intake ports facing the combustion chambers, and two exhaust ports are formed. [Industrial Applicability]

[0050] The range extender for an automobile according to the present invention is suitably used for extending the driving range of a BEV. [Explanation of symbols]

[0051] (1): range extender for automobiles, (2): engine dedicated to generating electricity, (3): generator, (3a): rotating shaft, (4): fuel tank, (5): cooling system, (11): crankshaft, (12): cylinder, (13): piston, (14): intake manifold, (15): cylinder block, (16): cylinder head, (17): combustion chamber, (18): intake port, (19): exhaust port, (21); intake valve, (22): exhaust valve, (23): valve train , (24): first valve train unit, (25): second valve train unit, (26): first camshaft, (27): first cam, (28): first push rod, (29): first rocker arm, (31): second camshaft, (32): second cam, (33): second push rod, (34): second rocker arm, (36)(37): space, (38): surge tank, (39): branch pipe, (40): intake manifold, (41): surge tank, (42): branch pipe.

Claims

1. A range extender for a battery electric vehicle, which is provided with a power generation engine, a generator that generates electricity by driving the power generation engine, a fuel tank for the power generation engine, and a cooling device for the power generation engine, and which supplies power to a drive battery of the battery electric vehicle, a range extender for a battery electric vehicle, wherein the power-generation-only engine is a horizontally opposed two-, four- or six-cylinder engine having a crankshaft with a horizontal central axis of rotation, an even number of cylinders arranged opposite each other on either side of the crankshaft, and pistons arranged in each cylinder so as to face each other on either side of the crankshaft; the generator is arranged approximately in the center of the length of the power-generation-only engine so that the power-generation-only engine and the generator are T-shaped in a plan view, and the rotation axis of the generator is arranged horizontally on the same axis as the crankshaft or on an axis parallel to the crankshaft and is connected to the crankshaft.

2. 2. A range extender for a battery electric vehicle as described in claim 1, wherein the generator-only engine is provided with an intake manifold having a surge tank and a branch pipe in an intake air path and supplying intake air to an intake port provided in the cylinder head, and the surge tank of the intake manifold is arranged along a side of the generator-only engine opposite to the side on which the generator is arranged, and / or along a portion of a top surface of the generator-only engine opposite to the side on which the generator is arranged.

3. 3. The range extender for a battery electric vehicle according to claim 2, wherein a tip end of the branch pipe of the intake manifold is connected to an upper surface of a cylinder head of the generator-only engine.

4. 3. A range extender for a battery electric vehicle as claimed in claim 2, wherein the generator-only engine is a horizontally opposed two-cylinder engine having one cylinder on each side of the crankshaft, i.e., two cylinders on the left and right, and a tip of a branch pipe of the intake manifold is connected to a side of a cylinder head of the generator-only engine.

5. 2. The range extender for a battery electric vehicle as described in claim 1, wherein the fuel tank is arranged so that the entire fuel tank is contained within at least one of two spaces surrounded by a vertical plane on which both longitudinal ends of the generator-only engine are located and a vertical plane on which a tip of the generator protruding from the generator-only engine is located.

6. 2. The range extender for a battery electric vehicle as described in claim 1, wherein the fuel tank is arranged to be entirely contained within one of two spaces surrounded by a vertical plane on which both longitudinal ends of the power generation engine are located and a vertical plane on which an end of the generator protruding from the power generation engine is located, and the cooling device is arranged to be at least partially contained within the other space.

7. The engine for generating electricity comprises a cylinder block in which cylinders are formed, a cylinder head in which combustion chambers are formed corresponding to each cylinder and in which two intake ports and two exhaust ports facing the combustion chambers are formed, two intake valves for opening and closing both intake ports of each combustion chamber, two exhaust valves for opening and closing both exhaust ports of each combustion chamber, and a valve mechanism for opening and closing all intake valves and all exhaust valves, the valve mechanism being composed of a first valve unit for opening and closing all intake valves and a second valve unit for opening and closing all exhaust valves, the first valve unit being composed of a first camshaft rotated about a horizontal rotation central axis by a crankshaft, a first push rod driven by a cam of the first camshaft, and a first rotor driven by the first push rod.

2. The range extender for a battery electric vehicle according to claim 1, wherein the second valve operating unit comprises a second camshaft rotated about a horizontal rotational center axis by the crankshaft, a second pushrod driven by a cam of the second camshaft, and a second rocker arm driven by the second pushrod, and transmits input from the cam of the second camshaft to all of the exhaust valves, one of the first camshaft and the second camshaft being disposed at a height position above the cylinder and directly above the crankshaft, and the other being disposed at a height position below the cylinder and directly below the crankshaft.

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