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Future trends in automobile design
The aim of this chapter is to:
? Demonstrate the mechanical and electrical possibilities for future vehicle design;
? Indicate how current advances will create fundamental design changes for future vehicles.
1.1 Introduction
The design of modern cars has already reached the stage where the Ford Fiesta has more computing power than Space Shuttle. There is definitely going to be a great expansion in electrical control and its attendant systems. To make this distinction more obvious this chapter has been split into electrical and mechanical future possibilities, but this does in no way mean that these two futures are separate, they are inevitably intertwined. There are many future possibilities but now more than ever before they are dependent on the development of future technologies, such as electrical systems using light as a carrier medium.
1.2 Mechanical possibilities
This section is split into six areas where significant changes will occur in the near future,however this does not preclude changes in other areas of vehicle design that may have a profound effect on these designs. There is inevitably an inter-linking between mechanical and electrical possibilities, so where this occurs the emphasis has been placed on the electrical side as this is the area that will show most change over the coming years.
1.2.1 Design possibilities
There are approximately 15 000 components that make up an automobile. Each of these components needs to be designed for efficient use of materials and costed down to a price. Each one must have a suitable reliability since any failure will inevitably result in customer dissatisfaction.
This results in the total component number continuously dropping to increase reliability and drive costs down. Systems such as FMEA (Failure Modes and Effects Analysis), ENTRA and weighted objectives methods (Cross, 1989) can be used effectively to optimize design and reduce component numbers. A recent example is a development of an engine design where the basic layout remained but a redesign reduced the number of components by seventy. This was in spite of the fact that the redesign contained new features such as liquid cooling and four valves per cylinder.
It should be noted that the quality of the final assembly is always a function of the number of component parts.The use of these processes will increase, especially with the aid of computerized integrated design packages. There are many possibilities here but several may well be:
(a) design packages where the designer is continually updated on all the legal implications of each design change, thereby avoiding international vehicle acceptance problems.
(b) at the concept design stage previous models and current competitor vehicles could be analysed to create design envelopes for a new vehicle. These envelopes, which could be external shape, drive system design or interior layout, could then be explored to create new generations of vehicles.
(c) in a similar vein, new component parts could be developed with a computer system such that an existing part can be manipulated (by stretching, compressing, etc.) to quickly create a suitable new component. Obviously a life and reliability analysis would have to be performed but it avoids the blank sheet of paper situation. It could be argued that these systems could remove innovative ideas; however, it usually takes less time to develop an existing idea than create the idea from scratch. However, there will always be a need to practically test designs to confirm the computed outcomes.
This is of increasing importance as the times for vehicle programmes reduce. It currently takes approximately three years for a new vehicle to be produced from concept, but two years could well be on the horizon. This means the design and development programme has to be thoroughly integrated so that resources and manpower are available exactly as required. An increasing use of project planning and constant appraisal is also indicated, as any delay could be catastrophic for the project. Again, computers will be essential here not only to run the design and development programme but also to predict likely problem areas.
An increasing role is being played by parts suppliers as they take on the design and development of their products. This leaves the vehicle manufacturer to collect and collate the design data to ensure the product as a whole will have the required performance. Thus, a complex computer
network is being developed to enhance the design lead-time. This brings about the essential requirement that the design is constantly updated as changes are made, so that every group involved with the project is aware of the updates as they happen and can comment as necessary.
It also provides a record so that back-tracking can occur when necessary.
The recycling of vehicle parts will always be an issue, which again needs a continual interlinking of the groups concerned with design issues. The cost of strip-down and ease of recycling is reduced when there are compatible materials used in component assemblies; for example, the complete dash-panel should be made of compatible plastics so that no sorting or breaking down of the panel is required for recycling.
Prototype models of design variants can now and increasingly will be made from computer models by the use of Rapid Prototyping processes (Jacobs, 1996; Venus, 1997; Kalpakjian,1997). The time for these processes will reduce and will mean that tests such as coolant flow
visualization in engines can be performed before any metal has been cut. This will also aid the design of electrical systems against electromagnetic interference, which will become an increasingly important issue as the whole vehicle becomes computer controlled. These on-board computers could also be used to relay vehicle performance and reliability information back to the Future trends in automobile design
manufacturers so that the vehicle could be updated before any potential problems (and expensive recalls) occur. This could be a two-way process as vehicle transmitter/receiver (not necessarily of a radio type) could also receive updates as well.
Further methods for decreasing design and development time revolve around modular design systems. This process has been used for a long time, but the advent of cheap high-powered computers brings far more scope to this reality. Various manufacturers currently use this system for engine design, but this system could easily be brought into body design. This could be achieved, for example, by the use of lightweight space frame chassis structures (platforms) to which plastic clip-on body panels are attached. These panels could readily be changed in shape using injection moulding techniques, which could provide relatively inexpensive model re?vamps. New technology will inevitably bring with it new design possibilities, which could well be almost endless. These developments will mainly come from manufacturing processes becoming available with faster and improved final product properties. There is a definite trend towards lightweight materials, such as aluminium, where improved processing techniques will eliminate most of the machining processes. Styling will inevitably change to the limits of these processes, so for example the replacement of carbon in rubber with silicon or the use of prisms for mirrors could bring about a plethora of new design concepts. It is up to the design teams to realize the potential of these new technologies when they occur and exploit them fully.
1.2.2 Advances in manufacturing methods
Most automotive manufacturers currently have links of various forms with other automotive manufacturers. These ties will strengthen in the future mainly due to the economy of scale,especially with power systems and transmissions. There has also been a tendency for body styling to be updated regularly but the basic platform to remain similar to previous models, e.g.Ford Ka and Toyota Classic. This intermixing will create many new versions of basic vehicles without the costs of a completely new vehicle, so manufacturers will have a tendency for linking to create the broadest coverage of specifications for their vehicle range. This has further repercussions where, at least, first tier suppliers would be involved at all stages of the vehicle design. They could then supply and be responsible for complete systems. The main problem with this scenario is confidentiality with suppliers to more than one manufacturer. This can be alleviated by having a sole supplier relationship, patenting or allowing other manufacturers the use of designs for a fee.
These arrangements could result in the vehicle manufacturer having overall control of the design and development of its vehicles, but just being an assembler of component parts. Some manufacturers are already well down this path, and have a good showing within the market place. This is probably partly due to the extra control the vehicle assembler has on the quality of its bought-in parts. Some of these relationships are being formalized now in ‘Target Agreements’ which create a legal as well as a working relationship. There is now necessarily a logical end to this process as it depends on the strength of the linking, but would unquestionably mean that the limit would be the stage where the vehicle manufacturer feels that their individuality is brought into doubt, as this differentiates one company’s products from those of another. This
will create, however far down this route this process goes, a mutual responsibility which will have knock-on effects for all the workforces involved and could lead to ‘service support systems’ relating the vehicle manufacturer to its supply companies. The inter-linking of automotive
manufacturers may well lead to there being only three or four major players in the world market.
An extension to this, that some companies are already arranging, is to create a ‘supplier park’ where first tier companies are geographically located close to the assembly plant. This may be an obvious move for new companies, but for established ones it may not be so simple, especially when ‘Just in Time’ (JiT) systems are becoming the industry norm. This will result in clusters of automotive industry within countries and indeed, the world. Labour costs will vary from country to country over a period of time which means that labour intensive activities will be based on a short term basis geographically. A knock-on effect of modularization is that robotization is more effective which may bring an end to these short
term policies for most production plants. This would seem to be the case especially when the spiralling of future transport costs of components are considered.
Part of the emphasis in computer controlled manufacturing is that feedback loops could exist to continually reduce production times. This could be built into the manufacturing system so that the processes are continually monitored and optimized. Mathematical modelling of production lines could also be used as part of this feedback loop.
These processes could also be used to reduce the time taken to obtain a required production rate from a new line, or even for a new vehicle. Currently a new vehicle takes about thirty days from the start-up of the line to the required rate for most manufacturers. However, a few companies manage this in one day with efficient planning and feedback systems incorporated into their computer management systems.
Further use of computerized control systems could be used to improve various stages of production within the complete cycle. An example of this could be the elimination of hot engine testing from the production process. Once the characteristics of an engine have been evaluated with bandwidths set for the control variables, engines could be cold tested at low cranking
speeds to check factors such as crankshaft torque to turn, compression analysis, cylinder block airflow and liquid cavity leaks. Even NVH tests could be performed at, say, 1500 r.p.m. Again, the use of modularization would make such systems more economically feasible.
Another process that demonstrates the use of overall computer control by using experimental data as an initialization is painting by electrostatic deposition. These systems totally avoid the
use of solvents by using water as a carrier. Flake orientation (for metallic paints) can be determined by the charge and the position of the spray gun, which could be computer variables. The carrier water could then either be re-circulated after cleaning (which involves large cost
and potential contamination problems), or passed to filter beds and then into the local river system. This whole process could be automated once the system characteristics have been determined, so that these systems require systematic development but once set up could be self correcting for all eventualities. Implementation of such processes would greatly reduce costs and also minimize plant equipment costs. Such simplified control systems could be implemented throughout automotive production plants to improve final quality and reduce costs and provide innovative finishes.
It is certain that there will be an ever increasing technological advance that cannot be predicted, but these advances usually come through the application of older processes with new materials and control systems. An example of this is the use of hydra-forming. This process has been used for many years in the brass musical instrument manufacturing industry for forming complex curved tubes at fairly low fluid pressures. Advances in sealing technology mean that this process is currently used for the manufacture of camshafts and exhaust manifolds, but there is no reason why sills, rails and posts could not be manufactured by this process. This would avoid flanges and could thus make optimum use of the space taken by the current designs. This process of up-dating old processes will continue on the back of advances in appropriate technology.
1.2.3 Materials advances
The use of lightweight materials within road vehicles has been considered for at least twenty years (Automotive Engineering, 1991) but it is only recently that a few manufacturers have produced low volume mass production vehicles that use a substantial volume of these materials.
As yet there are no truly mass produced lightweight (approx. 500 kg) road vehicles, this is bound to change. Current projected vehicles propose 40% by weight of aluminium for a vehicle weighing 1 Mg. that would return 100 m.p.g. using a hybrid power system. Part of the reason for the concentration on a range of medium/large sized vehicles is that the return on development costs would be greater. Aspects of true mass production can also be explored with this type of vehicle before any major small car mass production takes place. However, aluminium is not the only contender for lightweight structures. The magnesium industry predicts (Automotive Engineering, 1993) a 15–20% annual growth within the automotive industry over the next ten years. Castings would be the most likely form of usage, and doors and dash-panels using this method have already been developed. Further uses could be for the nodes (lugs) of a space frame chassis and engine mountings. Other possible materials are highly ductile stainless steels with a yield stress over 800 MPa and high tensile steels. However, body shells need to be designed specifically for these materials and a direct replacement of current steel systems would not be appropriate. Part of this re-design would have to be a re-consideration of NVH properties. This could be aided by suitable positioning of sandwich construction
panels, which is currently used as ‘sound deadened’ steels, but the principle could be applied to other metals than steel, once the bonding technology has been developed. A further development would be to use plastics for the complete body shell including the windows, however at the moment their inherent brittle transition phase is hindering this advance.
A metal–plastic composite could be the answer here. It is reckoned that an aluminium body shell could weigh 60% of a steel equivalent and a plastic one could be even less than that. The assumption here is that there is sufficient package space to absorb this intrusion. Plastics currently have a very efficient application in the absorption of impact energy in race cars in the form of honeycomb structures. This technology is extremely expensive, but there are continuing pressures to develop this technology to reduce costs. This would be a great advance in road vehicle design and should, if implemented, radically alter body shapes and lengths.
Development prototype engines have been built where plastics have been the major material, up to about 80%, with the use of mainly ceramic coatings by various companies for racing and motorcycle use. Both these uses require lightweight and fast throttle response whereas the latter was also considered as a ‘throw-away’ engine. These engines have never got beyond the development stage to date, like many other prototype engines before them. However, plastics are finding their way below the bonnet as heat exchangers, cam covers, inlet manifolds and electric motor housings, so there could well be in the near future, a leap to plastic engines. Part of these advances is the development of processing technologies. Currently work is being centred on metal matrices and long fibre injection processes. Metal matrices have the advantage that their properties can be tuned to suit the particular application, where not only fibre or whisker density is altered but also their orientation. This tuning of properties would be of great use for engine components such as pistons and connecting rods. Combinations of metals, plastics and ceramics will be combined to create specific use composites for vehicle building of the future and just needs the technology to advance so that efficient mass-manufacturing processes can be developed.
外文資料譯文
未來的汽車設(shè)計(jì)趨勢(shì)
本章的目的是：
為今后的車輛設(shè)計(jì)展示機(jī)械和電氣方面的可能性；
說明目前的進(jìn)展將如何為未來的車輛帶來根本性的設(shè)計(jì)變化。
1.1 介紹
現(xiàn)代汽車的設(shè)計(jì)已經(jīng)達(dá)到了比航天飛機(jī)更有計(jì)算能力的階段。電氣控制肯定會(huì)有很大的擴(kuò)展，它的附屬系統(tǒng)。為了使這一區(qū)別更加明顯，這一章被分成了電氣和機(jī)械兩種未來的可能性，但這并不意味著這兩種未來是分開的。相提并論，它們不可避免地交織在一起。有許多未來的可能性，但現(xiàn)在比以往任何時(shí)候都更依賴于未來技術(shù)的發(fā)展，例如電氣系統(tǒng)的應(yīng)用。光作為載體介質(zhì)。
1.2機(jī)械可能性
本節(jié)分為六個(gè)領(lǐng)域，在不久的將來將發(fā)生重大變化，但這并不排除在車輛設(shè)計(jì)的其他領(lǐng)域發(fā)生的變化，這些變化可能會(huì)對(duì)車輛設(shè)計(jì)產(chǎn)生深遠(yuǎn)的影響。這些設(shè)計(jì)。機(jī)械和電氣的可能性之間不可避免地存在著相互聯(lián)系，因此在發(fā)生這種情況時(shí)，重點(diǎn)放在電氣方面，因?yàn)檫@是將在未來幾年中表現(xiàn)出最多的變化。
1.2.1設(shè)計(jì)可能性
大約有15000個(gè)組成汽車的部件。這些部件中的每一個(gè)都需要被設(shè)計(jì)用于有效地使用材料并將成本降低到一個(gè)價(jià)格。每個(gè)人都必須有一個(gè)表可靠性由于任何故障將不可避免地導(dǎo)致客戶不滿。這導(dǎo)致總部件數(shù)不斷下降，以增加可靠性和降低驅(qū)動(dòng)成本。系統(tǒng)，如故障模式和影響分析和加權(quán)目標(biāo)方法可有效地用于優(yōu)化設(shè)計(jì)和減少部件號(hào)。最近的一個(gè)例子是發(fā)動(dòng)機(jī)設(shè)計(jì)的發(fā)展,其中基本布局仍然保留但重新設(shè)計(jì)紅色把組件的數(shù)量減少了70。這是盡管重新設(shè)計(jì)包含了新的特點(diǎn)，如液體冷卻和每缸四個(gè)閥門。
應(yīng)該注意的是，最終裝配的質(zhì)量總是取決于零件的數(shù)量，這些過程的使用將會(huì)增加，特別是借助計(jì)算機(jī)化的額定設(shè)計(jì)包。這里有許多可能性，但有幾個(gè)可能是：
（a）設(shè)計(jì)包裝，設(shè)計(jì)人員不斷更新每次設(shè)計(jì)變更的所有法律影響，從而避免國(guó)際車輛驗(yàn)收問題。
（b）在概念設(shè)計(jì)階段，可以分析以前的車型和當(dāng)前的競(jìng)爭(zhēng)對(duì)手車輛，以創(chuàng)建新車輛的設(shè)計(jì)包絡(luò)。這些封套可以是外部形狀，驅(qū)動(dòng)器設(shè)計(jì)或內(nèi)部布局，然后可以被探索以創(chuàng)建新一代車輛。
（c）在類似的靜脈中，可以使用計(jì)算機(jī)系統(tǒng)開發(fā)新的部件，以便能夠（通過拉伸、壓縮等）操作現(xiàn)有零件快速創(chuàng)建合適的新功能。組件。顯然，必須進(jìn)行壽命和可靠性分析，但它避免了白紙的情況?？梢哉f，這些系統(tǒng)可以消除創(chuàng)新的想法；當(dāng)然，開發(fā)一個(gè)現(xiàn)有的想法通常比從頭開始創(chuàng)建這個(gè)想法花費(fèi)的時(shí)間更少。然而，總是需要實(shí)際測(cè)試設(shè)計(jì)，以確定計(jì)算結(jié)果。
隨著車輛計(jì)劃時(shí)間的減少，這一點(diǎn)越來越重要。目前一款新的汽車從概念上生產(chǎn)大約需要三年時(shí)間，但很可能需要兩年時(shí)間。地平線。這意味著設(shè)計(jì)和發(fā)展方案必須徹底整合，以便完全按照需要提供資源和人力。越來越多地使用項(xiàng)目規(guī)劃還指出經(jīng)常進(jìn)行評(píng)估，因?yàn)槿魏瓮涎佣伎赡軐?duì)項(xiàng)目造成災(zāi)難性后果。再說一遍，計(jì)算機(jī)在這里不僅是運(yùn)行設(shè)計(jì)和開發(fā)程序的關(guān)鍵，而且也是前置程序所必需的。阻斷可能的問題區(qū)域。零件供應(yīng)商在產(chǎn)品的設(shè)計(jì)和開發(fā)過程中扮演越來越重要的角色。這就離開了汽車制造商收集和膠設(shè)計(jì)數(shù)據(jù)以確保整個(gè)產(chǎn)品具有所需的性能。因此,復(fù)雜的計(jì)算機(jī)正在開發(fā)網(wǎng)絡(luò)以提高設(shè)計(jì)提前期。這就帶來了設(shè)計(jì)不斷更新為變化的基本要求，使每一組與TH相關(guān)項(xiàng)目在發(fā)生時(shí)意識(shí)到更新，并且可以根據(jù)需要進(jìn)行評(píng)論。它還提供了一個(gè)記錄，以便在必要時(shí)可以進(jìn)行反向跟蹤。
車輛零件的循環(huán)再造永遠(yuǎn)是一個(gè)問題，這再次需要與設(shè)計(jì)問題有關(guān)的小組不斷地相互聯(lián)系。降低了拆下成本，降低了回收利用的難度。當(dāng)組件中使用兼容的材料時(shí)，例如，完整的儀表板應(yīng)該由相容的塑料制成，這樣就不需要對(duì)面板進(jìn)行分類或分解來回收利用。
設(shè)計(jì)變體的原型模型現(xiàn)在可以并將越來越多地通過使用快速原型程序從計(jì)算機(jī)模型中制造出來(Jacobs，1996年；維納斯，1997年)的時(shí)間過程將減少，并將意味著測(cè)試，如冷卻劑流量。在任何金屬被切割之前，可以在發(fā)動(dòng)機(jī)中進(jìn)行可視化。這也將有助于設(shè)計(jì)抗電磁干擾的電氣系統(tǒng)，電磁干擾將成為一種日益重要的手段。重要的問題，因?yàn)檎麄€(gè)車輛成為計(jì)算機(jī)控制。這些車載計(jì)算機(jī)也可以用來傳遞汽車性能和可靠性信息，回到汽車未來的發(fā)展趨勢(shì)。設(shè)計(jì)制造商使車輛可以在任何潛在的問題(和昂貴的召回)發(fā)生之前得到更新。這可能是一個(gè)作為車輛發(fā)射機(jī)/接收器的雙向過程。也可以接收更新。
進(jìn)一步的減少設(shè)計(jì)和開發(fā)時(shí)間的方法圍繞模塊化設(shè)計(jì)系統(tǒng)進(jìn)行。這個(gè)過程已經(jīng)很久了，但是廉價(jià)的大功率計(jì)算機(jī)的出現(xiàn)帶來了很遠(yuǎn)更多的范圍應(yīng)用