GB2551615A

GB2551615A - Electrical vehicle chasis and method of adapting internal combustion engine vehicle chasses for electrical vehicle drive train

Info

Publication number: GB2551615A
Application number: GB1706021.1A
Authority: GB
Inventors: lam Albert
Original assignee: Detroit Electric EV Technologies Zhejiang Ltd
Current assignee: Detroit Electric EV Technologies Zhejiang Ltd
Priority date: 2017-04-13
Filing date: 2017-04-13
Publication date: 2017-12-27
Anticipated expiration: 2037-04-13
Also published as: GB2551615B; GB201706021D0

Abstract

Disclosed is a method of adapting a vehicle chassis designed for accommodating an internal combustion engine to make it suitable for an electrical drive train. The chassis includes a pair of front wheels and associated suspensions, a pair of rear wheels and associated suspensions, and a chassis platform to which the wheel suspensions are coupled. A transverse beam member is located between the front and rear wheels. The method includes increasing a stiffness of coil springs of the front wheel suspensions, increasing a stiffness of a transverse roll/sway bar mutually linking the front wheel suspensions, and removing at least a part of the transverse beam member of the vehicle chassis to make a cavity for accommodating a battery unit 400 that has a structural rigidity that at least partially compensates for said removal. The method may also include increasing a strength of an anti-roll/roll-over bar 410. The method may include substituting an internal combustion engine for an electrical motor arrangement. Also disclosed is a vehicle chassis with the above features. The suspension may be a double wishbone suspension with dampers.

Description

ELECTRICAL VEHICLE CHASSIS AND METHOD OF ADAPTING INTERNAL COMBUSTION ENGINE VEHICLE CHASSES FOR ELECTRICAL VEHICLE DRIVE TRAIN

TECHNICAL FIELD

The present disclosure relates to electrical vehicle chasses. Moreover, the present disclosure also relates to methods of adapting an internal combustion engine vehicle chassis to make it suitable for use with an electrical vehicle drive train. Moreover, the present disclosure is concerned with methods of manufacturing aforesaid electrical vehicle chasses.

BACKGROUND

Conventionally, internal combustion engine vehicles include fuel tanks for storing combustible fuel that is used for providing motive power from internal combustion engines of the vehicles. Generally, such a fuel tank is arranged between a cabin of a given vehicle comprising a seating arrangement and rear wheels of the given vehicle. Furthermore, pure electrical vehicles and hybrid electrical vehicles (including both an internal combustion engine and an electric drive train) include a battery unit and an electric motor for driving the vehicles. It will be appreciated that the battery units of such electrical vehicles have a different weight distribution as compared to the fuel tanks of the internal combustion engine vehicles. For example, the battery units of pure electrical vehicles can weigh several hundred kilograms more than fully filled fuel tanks of internal combustion engine vehicles. Moreover, arrangements of the battery units in a floor region of the electrical vehicles may require a height of the seating arrangement to be raised, thereby changing the weight distribution (such as centre of gravity) of the electrical vehicles.

Normally, such a change in weight distribution of electrical vehicles due to the battery units thereof is overcome by modifications to the electrical vehicles. For example, the battery unit may be arranged in the electrical vehicle between the seating arrangement in the cabin and rear wheels of the vehicle. Such arrangement of the battery unit may require modification of the electrical vehicle, for example, to a chassis thereof. However, modification to the chassis of the electrical vehicle causes problems such as a reduction in torsional strength of the chassis. Furthermore, the reduction in torsional strength of the chassis may adversely affect factors related to control of the vehicle, such as steering response and/or cornering ability. It will be appreciated that such adverse affect to control of the vehicle may lead to an unfavorable driving experience for a user of the vehicle. Additionally, a reduction in torsional strength may lead to structural weakness of the vehicle that further reduces safety of passengers of the vehicle in an event of the vehicle experiencing a collision.

Therefore, there exists a need to maintain the torsional strength of the chassis of the car subsequent to modification of the electrical vehicle.

SUMMARY

The present disclosure seeks to provide an improved electrical vehicle chassis.

Additionally, the present disclosure seeks to provide a method of adapting an internal combustion engine vehicle chassis to make it suitable for an electrical vehicle drive train.

Moreover, the present disclosure also seeks to provide an improved method of manufacturing an electrical vehicle chassis.

According to a first aspect, there is provided a method of adapting a vehicle chassis designed for accommodating an internal combustion engine to make it suitable for an electrical drive train, wherein the vehicle chassis includes a pair of front wheels and associated front wheel suspensions, a pair of rear wheels and associated rear wheel suspensions, a chassis platform to which the wheel suspensions are coupled, and a transverse beam member between the front pair of wheels and rear pair of wheels, characterised in that the method includes: (i) increasing a stiffness of coil springs of the front wheel suspensions; (ii) increasing a stiffness of a transverse roll bar mutually linking the front wheel suspensions; and (iii) removing at least a part of the transverse beam member of the vehicle chassis to make a cavity for accommodating a battery unit, wherein the battery unit has a structural rigidity that at least partially compensates for removal of the at least a part of the transverse beam member.

The improved vehicle chassis of the present disclosure enables effective absorption of vertical movement of the electrical vehicle due to additional weight of the battery unit therein; arrangement of the transverse roll bar reduces body roll experienced by the vehicle, and the battery unit compensates for reduction in torsional strength of the vehicle due to the cavity made in the vehicle for arrangement of the battery unit.

According to a second aspect, there is provided a vehicle chassis designed for accommodating an internal combustion engine to make it suitable for an electrical drive train, wherein the vehicle chassis includes a pair of front wheels and associated front wheel suspensions, a pair of rear wheels and associated rear wheel suspensions, a chassis platform to which the wheel suspensions are coupled, and a transverse beam member between the front pair of wheels and rear pair of wheels, characterised in that the vehicle chassis includes: (i) coil springs having a predetermined stiffness for the front wheel suspensions; (ii) a transverse roll bar, mutually linking the front wheel suspensions, having a predetermined stiffness; and (iii) the transverse beam member having a cavity for accommodating a battery unit, wherein the battery unit has a structural rigidity that at least partially compensates for reduced torsional strength caused by the cavity.

It will be appreciated that features of the invention are susceptible to being combined in various combinations without departing from the scope of the invention as defined by the appended claims.

The present invention is included in the general business context, which aims to substitute vehicles powered by traditional fuels, for example gasoline or diesel, by electric vehicles. In particular, the present invention is intended for use in electric vehicles used within cities, which can be highly beneficial to the local environment due to significant reduction of gaseous emissions as well as significant reduction of noise. Overall environmental benefits can also be significant when electric vehicles are charged from renewable energy sources.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein: FIG. 1 is a perspective view of a vehicle chassis designed for accommodating an internal combustion engine, wherein embodiments of the present disclosure are concerned with adapting the vehicle chassis designed for accommodating an internal combustion engine to make it suitable for an electrical drive train; FIG. 2 is a schematic illustration of a transverse roll bar linking front wheel suspensions, in accordance with an embodiment of the present disclosure; FIG. 3 is a perspective view of the vehicle chassis with the transverse beam member having a cavity for accommodating a battery unit, in accordance with an embodiment of the present disclosure; FIG. 4 is a perspective view of the vehicle chassis with the battery unit accommodated into the cavity, in accordance with an embodiment of the present disclosure; and FIG. 5 is an illustration of steps of a method of adapting a vehicle chassis designed for accommodating an internal combustion engine to make it suitable for an electrical drive train, in accordance with an embodiment of the present disclosure.

In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DETAILED DESCRIPTION OF EMBODIMENTS

In overview, embodiments of the present disclosure are concerned with improved electrical vehicle chasses, namely vehicle chasses that have been adapted for use with pure electrical vehicle drive trains. Moreover, embodiments of the present disclosure are concerned with methods of adapting internal vehicle chasses for making them suitable for use with electrical vehicle drive trains.

Referring to FIG. 1, there is shown an illustration of a perspective view of a vehicle chassis 100 designed for accommodating an internal combustion engine, wherein embodiments of the present disclosure are concerned with adapting such a vehicle chassis 100 to make it suitable for accommodating an electrical drive train. The vehicle chassis 100 includes a pair of front wheels (shown in FIG. 2) and associated front wheel suspensions 110, a pair of rear wheels and associated rear wheel suspensions (not shown), a chassis platform 120 to which the wheel suspensions are coupled, and a transverse beam member 130 disposed transversely (relative to an elongate axis of the vehicle chassis 100) at a location approximately mid-way along the vehicle chassis 100, namely between the front pair of wheels and rear pair of wheels. Furthermore, the vehicle chassis 100 includes coil springs 140 having a predetermined stiffness for the front wheel suspensions 110.

It will be appreciated that, in an internal combustion engine vehicle, motive power for driving wheels thereof is provided using combustible fuel in a fuel tank, and an internal combustion engine coupled to the fuel tank for receiving the combustible fuel therefrom. However, in an electrical vehicle, motive power for driving wheels thereof is provided using a battery unit (shown in FIG. 4) coupled to an electrical motor of an electrical drive train. In such an instance, a sprung weight of the electrical vehicle due to presence of the battery unit is more than a sprung weight of a corresponding internal combustion engine vehicle that was adapted to make it suitable for the electrical vehicle drive train; such an increase in sprung weight arises because of the battery unit (including one or more battery modules) has more weight than combustible fuel in the fuel tank. Moreover, in operation, the electrical vehicle is subjected to additional forces (for example, while turning) due to the additional weight of the battery unit. Furthermore, the forces are transferred to the vehicle chassis 100 and/or wheels of the electrical vehicle, for example, as a vertical movement (or "bounce") of the vehicle, that leads to an uncomfortable driving experience and reduced safety for a user of the electrical vehicle. Additionally, to overcome the additional forces, suspensions associated with wheels of the electrical vehicle are required to be more effective. In such instance, the vehicle chassis 100 of the electrical vehicle is provided with coil springs 140 having a predetermined stiffness for the front wheel suspensions 110, wherein the predetermined stiffness of the coil springs is more than stiffness of coil springs of suspensions of the corresponding internal combustion engine vehicle. In such an instance, the increased stiffness of the coil springs for the front wheel suspensions allows the suspensions to substantially compensate for the vertical movement of the vehicle and provides a more comfortable driving experience for the user of the vehicle. Optionally, the increase in stiffness of the coil springs is in a range of 25% to 100% of the stiffness of the coil springs as used for the internal combustion engine vehicle.

Referring next to FIG. 2, there is shown a schematic illustration 200 of a transverse roll bar 210 that is operable to link front wheel suspensions 110, in accordance with an embodiment of the present disclosure. The vehicle chassis (such as the vehicle chassis 100 of FIG. 1) includes the transverse roll bar 210, mutually linking the front wheel suspensions 110, having a predetermined stiffness. It will be appreciated that in operation of the electrical vehicle, each of the pair of front wheels 220 (and/or rear wheels) may experience different deflection from each other. For example, differential deflection of the wheels may be experienced during turning the vehicle around a corner, due to centrifugal forces, and due to a load carried by the electrical vehicle being unbalanced (such as in an instance when only one passenger is using the electrical vehicle) and/or due to irregularities in a road surface that the electrical vehicle is being driven on. In such an instance, the electrical vehicle may experience body roll towards one side of the vehicle (such as the side opposite to the turning direction). Furthermore, the transverse roll bar 210 is operable to function as a torsion spring to provide torsional strength to the suspension, to reduce body roll of the vehicle. Moreover, the additional weight of the battery unit of the electrical vehicle may further increase the body roll experienced by the electrical vehicle, for example when turning around a corner at a road junction. In such an instance, the increased stiffness of the transverse roll bar 210 enables a reduction of the body roll experienced by the electrical vehicle due to the additional weight of the battery unit included therein. Furthermore, such reduction of the body roll enables better handling (or control) of the electrical vehicle by its user (for example, its driver), further enabling an increase in safety thereof. Optionally, the front wheel suspensions 110 include a double wishbone suspension arrangement 230 for each wheel 220 of the pair of front wheels.

Optionally, the front wheel suspensions 110 further include a damper (not shown) for each wheel 220 of the pair of front wheels. In such instance, the dampers of each wheel 220 enable dampening of vibrations induced at the coil spring 140, thereby further enhancing a comfortable driving experience for the user. Optionally, the damper is at least one of a hydraulic damper or a pneumatic damper. In one example, the front wheel suspensions 110 may include an oil-filled hydraulic damper.

Referring next to FIG. 3, there is shown an illustration of a perspective view of the vehicle chassis 100 with the transverse beam member 130 having a cavity 300 for accommodating a battery unit, in accordance with an embodiment of the present disclosure. As shown, an upper portion of the traverse beam member 130 of the vehicle chassis 100 is removed, (for example, by omission, cutting or grinding) to create the cavity 300. It will be appreciated that creating the cavity 300 by removal of the upper portion of the traverse beam member 130 of the vehicle chassis 100 reduces a torsional strength along an elongate axis A-A' (passing from front to rear) of the vehicle chassis 100.

Referring to FIG. 4, there is shown an illustration of a perspective view of the vehicle chassis 100 with the battery unit 400 accommodated into the cavity 300, in accordance with an embodiment of the present disclosure. The battery unit 400 has a structural rigidity that at least partially compensates for a reduced torsional strength caused by creating the cavity 300, for example provided in a manner as aforementioned. As shown, the battery unit 400 is substantially L-shaped and is mounted into the cavity 300 by placing a long arm of the substantially L-shaped battery unit 400 into the cavity 300. Optionally, the short arm of the battery unit 300 is attached to the chassis 100 of the vehicle, for example, by bolting an outer casing of the battery unit 400 to the chassis 100. Moreover, the reduction in torsional strength with respect to the elongated axis of the vehicle due to removal of the upper portion of the traverse beam member 130 is compensated primarily by arrangement of the battery unit 400 in place of the removed upper portion the of the traverse beam member 130.

Optionally, as shown, the vehicle chassis further includes an anti-roll bar 410, having a predetermined strength; the anti-roll bar 410 extends peripherally around the battery unit 400 and is attached to side extremities of the vehicle chassis 100. The arrangement of the substantially L-shaped battery unit 400 between the front wheels and rear wheels of the electrical vehicle raises a centre of gravity of the electrical vehicle. It will be appreciated that such increase in centre of gravity increases a risk to safety of passengers of the electrical vehicle in an event of the electrical vehicle rolling over (for example, subsequent to experiencing a collision). In such an instance, the anti-roll bar 410 having the predetermined strength extending peripherally around the battery unit 400 and attached to side extremities of the vehicle chassis 100 substantially bears the additional weight of the battery unit 400 and thereby, increases safety of the passengers of the electrical vehicle. Additionally, the anti-roll bar 410 further increases the torsional strength of the vehicle chassis 100.

Referring to FIG. 5, illustrated are steps of a method 500 of adapting a vehicle chassis designed for accommodating an internal combustion engine to make it suitable for accommodating an electrical drive train, in accordance with an embodiment of the present disclosure. The vehicle chassis includes a pair of front wheels and associated front wheel suspensions, a pair of rear wheels and associated rear wheel suspensions, a chassis platform to which the wheel suspensions are coupled, and a transverse beam member between the front pair of wheels and rear pair of wheels. At a step 510, a stiffness of coil springs of the front wheel suspensions is increased; for example, the stiffness is increased in a range of 25% to 100% (wherein 100% corresponds to a doubling of the stiffness). At a step 520, a stiffness of a transverse roll bar, mutually linking the front wheel suspensions, is increased; for example, the stiffness is increased in a range of 25% to 100% (wherein 100% corresponds to a doubling of the stiffness). At a step 530, at least a part of the transverse beam member of the vehicle chassis is removed to make a cavity for accommodating a battery unit, wherein the battery unit has a structural rigidity that at least partially compensates for removal of the at least a part of the transverse beam member.

The steps 510 to 530 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. In an example, the method further includes increasing a strength of an anti-roll bar that extends peripherally around the battery unit and is attached to side extremities of the vehicle chassis. In another example, the method includes mounting the battery unit so that it can be removed from the vehicle chassis, for maintenance or replacement. In yet another example, method includes substituting the internal combustion engine of the vehicle chassis with an electrical motor arrangement that couples to an input drive shaft of a gearbox arrangement of the internal combustion engine.

Optionally, an electrical vehicle is manufactured by performing an adaptation of an internal combustion engine vehicle by substituting the internal combustion engine of the chassis with an electrical motor arrangement that couples to an input drive shaft of a gearbox arrangement of the internal combustion engine.

The vehicle chassis of the present disclosure that is adapted for an electrical drive train includes coil springs having increased stiffness as compared to coil springs of a corresponding vehicle chassis that is designed for an internal combustion engine. The coil springs having increased stiffness enhance an effectiveness of front wheel suspensions and enable the suspensions to substantially compensate for a vertical movement of the electrical vehicle generated due to additional weight of a battery unit included therein. Such absorption of the vertical movement allows a more comfortable experience for a user of the vehicle. Furthermore, the transverse roll bar with increased stiffness allows the electrical vehicle to reduce body roll of the vehicle. Such reduction of body roll enables better control of the vehicle by the user and further enhances the driving experience. Additionally, the battery unit that is accommodated in a cavity of a transverse beam member of the vehicle compensates for reduced torsional strength of chassis of the electrical vehicle. Such compensation of the reduced torsional strength increases effectiveness of the suspensions of the electrical vehicle, further increasing factors such as vehicle control, comfort and safety of passengers of the electrical vehicle.

Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a nonexclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

Claims

1. A method of adapting a vehicle chassis (100) designed for accommodating an internal combustion engine to make it suitable for an electrical drive train, wherein the vehicle chassis (100) includes a pair of front wheels (220) and associated front wheel suspensions (110), a pair of rear wheels and associated rear wheel suspensions, a chassis platform (120) to which the wheel suspensions are coupled, and a transverse beam member (130) between the front pair of wheels (220) and rear pair of wheels, characterised in that the method includes: (i) increasing a stiffness of coil springs (140) of the front wheel suspensions (110); (ii) increasing a stiffness of a transverse roll bar (210) mutually linking the front wheel suspensions (110); and (iii) removing at least a part of the transverse beam member (130) of the vehicle chassis (110) to make a cavity (300) for accommodating a battery unit (400), wherein the battery unit (400) has a structural rigidity that at least partially compensates for removal of the at least a part of the transverse beam member (130).

2. A method of claim 1, characterised in that the method further includes increasing a strength of an anti-roll bar (410) that extends peripherally around the battery unit (400) and is attached to side extremities of the vehicle chassis (100).

3. A method of claim 1 or 2, characterised in that the method includes mounting the battery unit (400) so that it can be removed from the vehicle chassis (100), for maintenance or replacement.

4. A method of any one of claims 1 to 3, characterised in that the method includes substituting the internal combustion engine of the vehicle chassis (100) with an electrical motor arrangement that couples to an input drive shaft of a gearbox arrangement of the internal combustion engine.

5. An electrical vehicle that is manufactured by performing an adaptation of an internal combustion engine vehicle, wherein the adaptation is achieved by using a method of any one of claims 1 to 4.

6. A vehicle chassis (100) designed for accommodating an internal combustion engine to make it suitable for an electrical drive train, wherein the vehicle chassis (100) includes a pair of front wheels (220) and associated front wheel suspensions (110), a pair of rear wheels and associated rear wheel suspensions, a chassis platform (120) to which the wheel suspensions are coupled, and a transverse beam member (130) between the front pair of wheels (220) and rear pair of wheels, characterised in that the vehicle chassis (100) includes: (i) coil springs (140) having a predetermined stiffness for the front wheel suspensions (110); (ii) a transverse roll bar (210), mutually linking the front wheel suspensions (110), having a predetermined stiffness; and (iii) the transverse beam member (130) having a cavity (300) for accommodating a battery unit (400), wherein the battery unit (400) has a structural rigidity that at least partially compensates for reduced torsional strength caused by the cavity (300).

7. A vehicle chassis (100) of claim 6, characterised in that the front wheel suspensions include a double wishbone suspension arrangement for each wheel of the pair of front wheels.

8. A vehicle chassis (100) of claim 7, characterised in that the front wheel suspensions (110) further include a damper for each wheel (220) of the pair of front wheels.

9. A vehicle chassis (100) of claim 8, characterised in that the damper is at least one of: a hydraulic damper, a pneumatic damper.

10. A vehicle chassis (100) of any one of the claims 6 to 9, characterised in that the vehicle chassis (100) further includes an anti-roll bar (410), having a predetermined strength that extends peripherally around the battery unit (400) and is attached to side extremities of the vehicle chassis (100).