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1、<p><b> 外文文獻(xiàn)原稿和譯文</b></p><p><b> 原 稿</b></p><p> Mechanical and Regenerative Braking Integration for a Hybrid Electric Vehicle</p><p><b> Abs
2、tract</b></p><p> Hybrid electric vehicle technology has become a preferred method for the automotive industry to reduce environmental impact and fuel consumption of their vehicles. Hybrid electric ve
3、hicles accomplish these reductions through the use of multiple propulsion systems, namely an electric motor and internal combustion engine, which allow the elimination of idling, operation of the internal combustion engi
4、ne in a more efficient manner and the use of regenerative braking. However, the added cost of the </p><p> A more cost effective design of an electro-hydraulic braking system is presented. The system electr
5、o-mechanically controlled the boost force created by the brake booster independently of the driver braking force and with adequate time response. The system allowed for the blending of the mechanical and regenerative bra
6、king torques in a manner transparent to the driver and allowed for regenerative braking to be conducted efficiently.</p><p> A systematic design process was followed, with emphasis placed on demonstrating c
7、onceptual design feasibility and preliminary design functionality using virtual and physical prototyping. The virtual and physical prototypes were then used in combination as a powerful tool to validate and develop the s
8、ystem. The role of prototyping in the design process is presented and discussed.</p><p> Through the experiences gained by the author during the design process, it is recommended that students create physic
9、al prototypes to enhance their educational experience. These experiences are evident throughout the thesis presented.</p><p> 1.1 Modern Hybrid Electric Vehicles</p><p> With rising gas prices
10、 and the overwhelming concern for the environment, consumers and the government have forced the automotive industry to start producing more fuel efficient vehicles with less environmental impact. One promising method tha
11、t is currently being implemented is the hybrid electric vehicle.</p><p> Hybrid vehicles are defined as vehicles that have two or more power sources [25]. There are a large number of possible variations, bu
12、t the most common layout of hybrid vehicles today combines the power of an internal combustion engine (ICE) with the power of an electric motor and energy storage system (ESS). These vehicles are often referred to as hyb
13、rid electric vehicles (HEV’s) [25]. These two power sources are used in conjunction to optimize the efficiency and performance of the vehicle, whic</p><p> Hybrid electric vehicles have the distinct advanta
14、ge of regenerative braking. The electric motor, normally used for propulsion, can be used as a generator to convert kinetic energy of the vehicle back into electrical energy during braking, rather than wasting energy as
15、heat. This electrical energy can then be stored in an ESS (e.g. batteries or ultracapacitors) and later released to propel the vehicle using the electric motor.</p><p> This process becomes even more import
16、ant when considering the energy density of batteries compared to gasoline or diesel fuel. Energy density is defined as the amount of energy stored in a system per unit volume or mass [44]. To illustrate this point, 4 kil
17、ograms (4.5 litres) of gasoline will typically give a motor vehicle a range of 50 kilometres. To store the same amount of useful electric energy it requires a lead acid battery with a mass of about 270 kilograms [25]. Th
18、is demonstrates the nee</p><p> 1.2 Research Scope - Regenerative Braking Systems</p><p> The scope of the research presented is to create a low cost regenerative braking system to be used on
19、future economical hybrid vehicles to study the interaction between regenerative and mechanical braking of the system. This system should be able to control the combination of both regenerative and mechanical braking torq
20、ue depending on driver demand and should be able to do so smoothly and safely. Controlling the regenerative braking torque can be done using control algorithms and vector control</p><p> 2.1 Hybrid Electric
21、 Vehicle Overview</p><p> Hybrid vehicles have emerged as one of the short term solutions for reducing vehicle emissions and improving fuel economy. Over the past 10 years almost all of the major automotive
22、 companies have developed and released for sale their own hybrid electric vehicles to the public. The popularity of hybrid electric vehicles has grown considerably since the turn of the century. With enormous pressure to
23、 become more environmentally friendly and with unpredictable gas prices, the sales of hybrid electri</p><p> 2.1.1 Hybrid Configurations</p><p> For the past 100 years the objective of the hyb
24、rid has been to extend the range of electric vehicles and to overcome the problem of long recharging times [35]. There are three predominant hybrid electric vehicle configurations currently on the market today. These con
25、figurations are known as series hybrids, parallel hybrids and series/parallel hybrids.</p><p> Each configuration has its advantages and disadvantages which will be discussed in the following sections.</
26、p><p> Series Hybrids</p><p> In series hybrids the mechanical output from the internal combustion engine is used to drive a generator which produces electrical power that can be stored in the ba
27、tteries or used to power an electric motor and drive the wheels. There is no direct mechanical connection between the engine and the driven wheels. Series hybrids tend to be used in high power systems such as large truck
28、s or locomotives but can also be used for lower power passenger vehicles [18]. The mechanically generated electrica</p><p> There are many advantages made possible by the arrangement described above. It is
29、possible to run the ICE constantly at its most efficient operating point and share its electrical output between charging the battery and driving the electric motor. By operating the engine at its most efficient operatin
30、g point, emissions can be greatly reduced and the most electrical power can be generated per volume of fuel. This configuration is also easierto implement into a vehicle because it is less complex w</p><p>
31、 Parallel Hybrids</p><p> In parallel hybrid configurations the mechanical energy output from the ICE is transmitted to a gearbox. In this gearbox the energy from the ICE can be mechanically combined with a
32、 second drive from an electric motor. The combined mechanical output is then used to drive the wheels [35]. In this configuration there is a direct connection between the engine and the driven wheels. As in series hybrid
33、s the controller compares the driver demand with the vehicle speed and output torque and determines </p><p> There are a number of advantages of a parallel hybrid over a series hybrid. The most important ad
34、vantage is that since only one conversion between electrical and mechanical power is made, efficiency will be much better than the series hybrid in which two conversions are required. Since the parallel hybrid has the ab
35、ility to combine both the engine and electric motor powers simultaneously, smaller electric motors can be used without sacrificing performance, while getting the fuel consumption and </p><p> Series/Paralle
36、l Hybrids</p><p> Combined hybrids have the features of both series and parallel configurations. They use a power split device to drive the wheels using dual sources of power (e.g. electric motor only, ICE
37、only or a combination of both). While the added benefits of both series hybrids and parallel hybrids are achieved for this configuration, control algorithms become very complex because of the large number of driving poss
38、ibilities available.</p><p> 2.1.2 Degree of Hybridization</p><p> Since most HEV’s on the road today are either parallel or series/parallel, it is useful to define a variable called the ‘degr
39、ee of hybridization’ to quantify the electrical power potential of these vehicles.</p><p> The degree of hybridization ranges from (DOH = 0) for a conventional vehicle to (DOH = 1) for an all electric vehic
40、le [25]. As the degree of hybridization increases, a smaller ICE can be used and operated closer to its optimum efficiency for a greater proportion of the time, which will decrease fuel consumption and emissions. The ele
41、ctric motor power is denoted by Pem and the internal combustion engine power is denoted by Pice.</p><p> Micro Hybrid</p><p> Micro hybrids have the smallest degree of hybridization and usuall
42、y consist of an integrated starter generator (ISG) connected to the engine crankshaft. The ISG allows the engine to be shut off during braking and idling to conserve fuel and then spins the crankshaft up to speed before
43、fuel is injected during acceleration. The ISG also provides small amounts of assist to the ICE during acceleration and acts as a generator to charge the batteries during braking. Micro hybrids usually improve fuel </p
44、><p> Mild Hybrid</p><p> Mild hybrids have a similar architecture to the micro hybrid except that the ISG is uprated in power to typically greater than 20 kW. However, the energy storage system
45、is limited to less than 1 kWh [35]. Mild hybrids usually have a very short electric-only range capability but can provide a greater assist to the ICE during accelerations. The electrical components in a mild hybrid are m
46、ore complex than a micro hybrid and play a greater role in the vehicle operation. Fuel economy can be improved </p><p> Full Hybrid</p><p> Full hybrids do away with the ISG and replace it wit
47、h a separate electric motor and alternator/starter that perform the same function. The electric motor has the ability to propel the vehicle alone, particularly in city (stop and go) driving. The energy storage system is
48、upgraded to improve electric-only range capability and the engine is usually downsized to improve fuel economy and emissions. Full hybrids can achieve 40 to 45 percent fuel consumption reductions over non hybrids [53].&l
49、t;/p><p> Plug-in Hybrid</p><p> Plug-in hybrids are very similar to full hybrids except that they have a much larger ESS that can be connected to an outside electrical utility source for chargin
50、g. These vehicles use only the electric motor to propel the vehicle within the range of the batteries and then operate like full hybrids once the batteries have discharged to a predefined level.</p><p> 2.1
51、.3 Fundamentals of Regenerative Braking</p><p> One of the most important features of HEV’s is their ability to recover significant amounts of braking energy. The electric motors can be controlled to operat
52、e as generators during braking to convert the kinetic energy of the vehicle into electrical energy that can be stored in the energy storage system and reused. However, the braking performance of a vehicle also greatly af
53、fects vehicle safety. In an emergency braking situation the vehicle must be stopped in the shortest possible distance and </p><p> Generally, the braking torque required is much larger than the torque that
54、an electric motor can produce [12]. Therefore, a mechanical friction braking system must coexist with the electrical regenerative braking. This coexistence demands proper design and control of both mechanical and electri
55、cal braking systems to ensure smooth, stable braking operations that will not adversely affect vehicle safety.</p><p> Energy Consumption in Braking</p><p> Braking a 1500 kg vehicle from 100
56、km/h to 0 km/h consumes about 0.16 kWh of energy based on Equation 2.2.</p><p> If 25 percent of this energy could be recovered through regenerative braking techniques, then Equation 2.2 can be used to esti
57、mate that this energy could be used to accelerate the vehicle from 0 km/h to about 50 km/h, neglecting aerodynamic drag, mechanical friction and rolling resistance during both braking and accelerating. This also assumes
58、that the generating and driving modes of the electric motor are 100% efficient. This suggests that the fuel economy of HEV’s can be greatly increased when</p><p> 2.1.4 Methods of Regenerative Braking</p
59、><p> There are two basic regenerative braking methods used today. These methods are often referred to as parallel regenerative braking and series regenerative braking. Each of these braking strategies have ad
60、vantages and disadvantages that will be discussed in this section.</p><p> Parallel Regenerative Braking</p><p> During parallel regenerative braking, both the electric motor and mechanical br
61、aking system always work in parallel (together) to slow the vehicle down [48]. Since mechanical braking cannot be controlled independently of the brake pedal force it is converting some of the vehicle’s kinetic energy i
62、nto heat instead of electrical energy. This is not the most efficient regenerative braking method. However, parallel regenerative braking does have the advantages of being simple and cost effective. Fo</p><p&g
63、t; Series Regenerative Braking</p><p> During series regenerative braking the electric motor is solely used for braking. It is only when the motor or energy storage system can no longer accept more energy
64、that the mechanical brakes are used [48]. This method requires that the mechanical braking torque be controlled independently of the brake pedal force and has the advantage of being the most efficient by converting as mu
65、ch of the vehicle’s kinetic energy into electrical energy . The downfall of this method is that it brings many cos</p><p> 2.1.5 Current Regenerative Braking Systems</p><p> The current regene
66、rative braking system in most HEV’s (e.g. Toyota Prius) is the more costly electro-hydraulic braking (EHB) system. This system uses a brake pedal simulator, which is separate from the hydraulic braking circuit, to establ
67、ish driver braking demand. The braking demand is then proportioned into a regenerative and mechanical braking demand. The mechanical braking demand is then sent to a system that contains a high pressure hydraulic pump, a
68、ccumulator and proportional control valves</p><p><b> 譯 文</b></p><p> 混合動(dòng)力電動(dòng)汽車機(jī)械和再生制動(dòng)的整合</p><p><b> 摘 要</b></p><p> 為了減少對(duì)環(huán)境的污染和車輛的燃油消耗,混合
69、動(dòng)力電動(dòng)汽車已經(jīng)成為汽車工業(yè)的首選方法。混合動(dòng)力電動(dòng)汽車通過使用由電動(dòng)馬達(dá)和內(nèi)燃發(fā)動(dòng)機(jī)組成的混合動(dòng)力系統(tǒng)來達(dá)到減少環(huán)境污染和燃油消耗的目的。混合動(dòng)力系統(tǒng)消除了怠速,使發(fā)動(dòng)機(jī)以一種更有效的方式運(yùn)行,增加了再生制動(dòng)的使用。但是,混合動(dòng)力的成本的增加阻礙了這些車輛的銷售。</p><p> 在這里提出一個(gè)更具成本效益的電液制動(dòng)系統(tǒng)的設(shè)計(jì)。該系統(tǒng)使用電控機(jī)械結(jié)合的控制方式控制制動(dòng)助力器產(chǎn)生的推動(dòng)力,并有足夠的時(shí)間反應(yīng)。
70、這個(gè)系統(tǒng)使駕駛員清楚地了解機(jī)械和再生制動(dòng)力矩的混合,使再生制動(dòng)力系統(tǒng)得到有效的控制。</p><p> 一個(gè)系統(tǒng)化的設(shè)計(jì)過程是其次,重點(diǎn)在于展示概念設(shè)計(jì)方案的可行性和使用虛擬和實(shí)物模型的初步設(shè)計(jì)功用。虛擬和實(shí)物模型的結(jié)合使用成為驗(yàn)證和開發(fā)系統(tǒng)的強(qiáng)大工具,本文將介紹和討論在設(shè)計(jì)過程中模型所起到的作用。</p><p> 因?yàn)樵谠O(shè)計(jì)過程中設(shè)計(jì)者可以獲得相關(guān)的經(jīng)驗(yàn),提倡學(xué)生設(shè)計(jì)實(shí)物模型,以提
71、高學(xué)生的學(xué)習(xí)經(jīng)驗(yàn)。很明顯,這正是本文所要提出的。</p><p> 1.1現(xiàn)代混合動(dòng)力電動(dòng)汽車</p><p> 隨著油價(jià)的上漲和環(huán)境保護(hù)意識(shí)的提高,消費(fèi)者和政府迫使汽車行業(yè)開始生產(chǎn)省油和對(duì)環(huán)境污染小的汽車。一個(gè)有前景的方法就是現(xiàn)在實(shí)行的混合動(dòng)力電動(dòng)汽車。</p><p> 混合動(dòng)力汽車指的是有兩個(gè)或兩個(gè)以上動(dòng)力來源的車輛?;旌蟿?dòng)力汽車動(dòng)力的來源可能有很多的不
72、同,但是現(xiàn)在混合動(dòng)力汽車最常見的布局是由內(nèi)燃發(fā)動(dòng)機(jī)和電動(dòng)馬達(dá),能量?jī)?chǔ)存系統(tǒng)共同輸出動(dòng)力,這樣的車輛就叫混合動(dòng)力電動(dòng)汽車。汽車可以同時(shí)使用發(fā)動(dòng)機(jī)和電動(dòng)馬達(dá)輸出的動(dòng)力,從而可以提高汽車的使用性能和效率,進(jìn)而又可以提高燃油經(jīng)濟(jì)性,減少?gòu)U氣的排放,同時(shí)還能滿足消費(fèi)者對(duì)汽車性能的要求。1997年,豐田成普瑞斯為了第一款混合動(dòng)力電動(dòng)汽車,在日本進(jìn)行了批量生產(chǎn)。本田公司花費(fèi)了三年的時(shí)間進(jìn)行混合動(dòng)力電動(dòng)車的生產(chǎn),然后進(jìn)軍北美市場(chǎng)。豐田普瑞斯在北美發(fā)行幾
73、個(gè)月后,本田Insight緊隨其后也在北美進(jìn)行發(fā)行。</p><p> 混合動(dòng)力電動(dòng)車具有再生制動(dòng)系統(tǒng)的獨(dú)特優(yōu)勢(shì)。在制動(dòng)過程,通常用于動(dòng)力輸出的電動(dòng)馬達(dá),可以起到發(fā)電機(jī)的功用,把汽車的動(dòng)能轉(zhuǎn)化為蓄電池的電能,而不會(huì)轉(zhuǎn)化為熱能浪費(fèi)掉。轉(zhuǎn)換的電能可以儲(chǔ)存到蓄電池中,然后可以作為電動(dòng)馬達(dá)驅(qū)動(dòng)汽車使用的能量。</p><p> 考慮到蓄電池能量密度時(shí),動(dòng)能轉(zhuǎn)換為電能這個(gè)過程就更加重要了。能量密
74、度是指單位體積或質(zhì)量下能量?jī)?chǔ)存系統(tǒng)所儲(chǔ)存的能量。為了說明這一點(diǎn),我們可以做個(gè)對(duì)比,4.5公升的汽油通??梢跃S持一輛汽車行駛50千米。而要把相同的能量?jī)?chǔ)存到蓄電池中,則需要一個(gè)質(zhì)量約為270千克的鉛酸蓄電池。這就說明了在汽車行駛過程中能夠有效地儲(chǔ)存再生制動(dòng)系統(tǒng)產(chǎn)生的能量的重要性,從而可以保證在提高混合動(dòng)力電能車性能的前提下,不至使能量?jī)?chǔ)存系統(tǒng)所占體積過大。</p><p> 1.2再生制動(dòng)系統(tǒng)研究范圍</p
75、><p> 本文所提出的再生系統(tǒng)的研究范圍是研究再生制動(dòng)系統(tǒng)和機(jī)械制動(dòng)系統(tǒng)之間相互作用的關(guān)系,目的是設(shè)計(jì)開發(fā)出一個(gè)低成本的再生制動(dòng)系統(tǒng),從而可以應(yīng)用到未來經(jīng)濟(jì)型的混合動(dòng)力電動(dòng)汽車上。這個(gè)系統(tǒng)可以根據(jù)駕駛員的需要進(jìn)而控制再生制動(dòng)系統(tǒng)和機(jī)械制動(dòng)系統(tǒng)產(chǎn)生的制動(dòng)力矩的結(jié)合,還應(yīng)該保證這個(gè)過程的平順性和安全性。再生制動(dòng)力矩是通過使用的異步電動(dòng)機(jī)的矢量控制算法進(jìn)行控制的。但是,獨(dú)立地控制制動(dòng)踏板產(chǎn)生的機(jī)械制動(dòng)力矩,同時(shí)又要保持
76、機(jī)械制動(dòng)系在再生制動(dòng)系統(tǒng)失效后起到備用作用,這是一個(gè)很大的難題。為了解決這個(gè)問題,需要研究一個(gè)通過減少制動(dòng)主缸內(nèi)制動(dòng)液壓來來控制機(jī)械制動(dòng)系統(tǒng)產(chǎn)生的制動(dòng)力矩的制動(dòng)系統(tǒng)。</p><p> 2.1混合電動(dòng)汽車概述</p><p> 混合動(dòng)力電動(dòng)車已經(jīng)成為了可以在短時(shí)間內(nèi)減少汽車污染排放和提高燃油經(jīng)濟(jì)型的解決方法之一。在過去的10年幾乎所有的主要汽車公司都已經(jīng)向公眾發(fā)行銷售自己的混合動(dòng)力電動(dòng)
77、汽車,混合動(dòng)力電動(dòng)汽車的普及和銷售在這個(gè)世紀(jì)有了很明顯的增長(zhǎng),隨著不可預(yù)測(cè)的汽油價(jià)格的增長(zhǎng)和對(duì)環(huán)境保護(hù)的關(guān)注,混合動(dòng)力電動(dòng)汽車的銷售將在最近幾年內(nèi)急劇增長(zhǎng)。</p><p> 2.1.1混合動(dòng)力裝置</p><p> 在過去100年來混合動(dòng)力的研究目標(biāo)是延長(zhǎng)電動(dòng)汽車的使用壽命,解決蓄電池的長(zhǎng)期充電問題。在目前市場(chǎng),現(xiàn)在主要有三種混合動(dòng)力裝置,這些混合動(dòng)力裝置為串聯(lián)混合動(dòng)力,并聯(lián)混合動(dòng)力
78、,串并聯(lián)混合動(dòng)力。每一種動(dòng)力裝置都有其優(yōu)點(diǎn)和缺點(diǎn),這將在以后的章節(jié)進(jìn)行討論。</p><p><b> 串聯(lián)混合動(dòng)力</b></p><p> 串聯(lián)混合動(dòng)力汽車使用發(fā)動(dòng)機(jī)輸出的動(dòng)力來驅(qū)動(dòng)發(fā)電機(jī)產(chǎn)生電能,這些電能可以儲(chǔ)存在蓄電池中,也可以用來驅(qū)動(dòng)電動(dòng)馬達(dá)來驅(qū)動(dòng)汽車。在串聯(lián)混合動(dòng)力汽車上,發(fā)動(dòng)機(jī)和驅(qū)動(dòng)輪之間沒有直接的機(jī)械連接,串聯(lián)混合動(dòng)力往往在高功率系統(tǒng)中使用,如大型
79、貨車或火車,也可以應(yīng)用到低功率的客運(yùn)車輛上。發(fā)動(dòng)機(jī)輸出的機(jī)械能和蓄電池輸出的電能可以通過電子控制器進(jìn)行控制接合,然后這個(gè)電子控制器通過比較駕駛員所需的動(dòng)力和汽車車速,電動(dòng)馬達(dá)輸出的轉(zhuǎn)矩,從而決定每個(gè)動(dòng)力源驅(qū)動(dòng)汽車行駛所要輸出的能量。在制動(dòng)過程中,這個(gè)電子控制裝置可以使電能輸出模式轉(zhuǎn)換為再生模式,直接把再生制動(dòng)系統(tǒng)產(chǎn)生的電能儲(chǔ)存在蓄電池內(nèi)。</p><p> 按照這種布置方式進(jìn)行設(shè)計(jì)有很多的優(yōu)點(diǎn)。發(fā)動(dòng)機(jī)可以保持高
80、效率的運(yùn)行,使發(fā)動(dòng)機(jī)產(chǎn)生的電能在蓄電池和驅(qū)動(dòng)馬達(dá)之間得到分配。發(fā)動(dòng)機(jī)在其最高效率的工況下運(yùn)行,排放可以大大降低,燃燒每體積的燃料可以產(chǎn)生更多的電能。因?yàn)榇?lián)動(dòng)力裝置結(jié)構(gòu)簡(jiǎn)單且成本低,這種動(dòng)力裝置很容在汽車上落實(shí)。</p><p><b> 并聯(lián)混合動(dòng)力</b></p><p> 在并聯(lián)混合動(dòng)力汽車中,發(fā)動(dòng)機(jī)輸出的機(jī)械功傳到變速箱中。發(fā)動(dòng)機(jī)輸出的機(jī)械功和電動(dòng)馬達(dá)輸出
81、的功在變速箱內(nèi)進(jìn)行機(jī)械式的接合,混合的機(jī)械功用于驅(qū)動(dòng)汽車行駛。在這種混合動(dòng)力裝置結(jié)構(gòu)中,發(fā)動(dòng)機(jī)和驅(qū)動(dòng)輪之間有直接的機(jī)械連接。在串聯(lián)混合動(dòng)力裝置中,電子控制器通過比較駕駛員所需的動(dòng)力和汽車車速,電動(dòng)馬達(dá)輸出的轉(zhuǎn)矩,從而決定每個(gè)動(dòng)力源驅(qū)動(dòng)汽車行駛所要輸出的能量,以滿足汽車行駛性能,獲得最佳的效率。正如串聯(lián)混合裝置一樣,并聯(lián)混合動(dòng)力也以相似的方法控制再生制動(dòng)。并聯(lián)混合動(dòng)力裝置通常應(yīng)用到低功率的電動(dòng)車中,這兩種驅(qū)動(dòng)力可以同時(shí)使用,提供更高的行駛
82、性能。</p><p> 與串聯(lián)混合動(dòng)力系統(tǒng)相比,并聯(lián)混合動(dòng)力系統(tǒng)有很多優(yōu)勢(shì)。其中最重要的一項(xiàng)優(yōu)勢(shì)是效率高,因?yàn)樵诓⒙?lián)混合動(dòng)力中,電能和機(jī)械能只需轉(zhuǎn)換一次,而在串聯(lián)混合動(dòng)力中,電能和機(jī)械能需要兩次轉(zhuǎn)換。由于并聯(lián)混合動(dòng)力可以使發(fā)動(dòng)機(jī)和電動(dòng)馬大產(chǎn)生的動(dòng)力同時(shí)結(jié)合起來,在不損失汽車行駛性能的前提下,可以使用體積小的電動(dòng)馬達(dá),同時(shí)也降低了油耗和排放。最后,并聯(lián)混合動(dòng)力汽車在行駛過程中只需使發(fā)動(dòng)機(jī)運(yùn)行,而不需要另一個(gè)發(fā)電
83、機(jī)為蓄電池充電。</p><p><b> 串、并聯(lián)混合動(dòng)力</b></p><p> 串并聯(lián)混合動(dòng)力裝置結(jié)合了串聯(lián)和并聯(lián)動(dòng)力裝置的特點(diǎn)。這種混合方式汽車通過使用動(dòng)力分配裝置來控制雙動(dòng)力源(電動(dòng)馬達(dá)輸出動(dòng)力,發(fā)動(dòng)機(jī)輸出動(dòng)力或者兩者同時(shí)輸出)驅(qū)動(dòng)汽車行駛。雖然這種裝置形式可以獲得串聯(lián)混合動(dòng)力裝置和并聯(lián)混合動(dòng)力裝置的優(yōu)點(diǎn),因?yàn)榭紤]到汽車實(shí)際行駛可能性,這種裝置的控制算
84、法會(huì)變得非常復(fù)雜。</p><p><b> 2.1.2混合度</b></p><p> 現(xiàn)在道路上行駛的混合動(dòng)力電動(dòng)汽車大多是串聯(lián)混合動(dòng)力,并聯(lián)混合動(dòng)力,或者串并聯(lián)混合動(dòng)力,因此定義一個(gè)‘混合度’變量來評(píng)價(jià)混合動(dòng)力電動(dòng)汽車的電能潛能是非常有意義的。</p><p> 混合度變從傳統(tǒng)車輛(DOH=0)到所有電動(dòng)車(DOH=1)之間變化,隨
85、著混合度的增加,在汽車上可以使用一個(gè)比較小的發(fā)動(dòng)機(jī),同時(shí)發(fā)動(dòng)機(jī)可以在最接近最佳效率的工況下運(yùn)行很長(zhǎng)的時(shí)間,這樣就可以減少燃油的消耗和廢氣的排放。電動(dòng)馬達(dá)輸出的功用表示,發(fā)動(dòng)機(jī)輸出的功用表示。</p><p><b> 微混合動(dòng)力</b></p><p> 微混合指的是最小混合度,通常是由一個(gè)連接到發(fā)動(dòng)機(jī)曲軸的綜合起動(dòng)發(fā)電機(jī)組成。在加速和怠速過程中,綜合起動(dòng)發(fā)電機(jī)使
86、發(fā)動(dòng)機(jī)處于關(guān)閉狀態(tài),從而節(jié)約燃油。加速時(shí),在燃油噴入汽缸之前,綜合起動(dòng)發(fā)電機(jī)使發(fā)動(dòng)機(jī)的曲軸加速旋轉(zhuǎn)。在加速過程中,綜合起動(dòng)發(fā)電機(jī)對(duì)發(fā)動(dòng)機(jī)起動(dòng)協(xié)助的作用,在制動(dòng)過程中,綜合起動(dòng)發(fā)電機(jī)還可以作為發(fā)電機(jī)向蓄電池充電。和非混合動(dòng)力汽車相比,微混合動(dòng)力汽車的燃油經(jīng)濟(jì)性可以提高10%左右。</p><p><b> 輕混合動(dòng)力</b></p><p> 輕混合動(dòng)力和微混合動(dòng)力
87、結(jié)構(gòu)相似,有一點(diǎn)不同的是其綜合起動(dòng)發(fā)電機(jī)是經(jīng)過改進(jìn)的,其輸出的動(dòng)力可以超過20KW。但是,輕混合動(dòng)力的能量?jī)?chǔ)存系統(tǒng)只能儲(chǔ)存1KWh左右的能量。輕混合動(dòng)力汽車只有一個(gè)很短的純電動(dòng)續(xù)航能力,但是可以在加速過程中給發(fā)動(dòng)機(jī)提供很大的輔助作用。輕混合動(dòng)力中的電子元件要比微混合動(dòng)力中的電子元件復(fù)雜的多,且在汽車行駛過程中發(fā)揮著更大的作用。和非混合動(dòng)力的汽車相比,輕混合動(dòng)力汽車的燃油經(jīng)濟(jì)性可以提高20%-25%左右。</p><p
88、><b> 全混合動(dòng)力</b></p><p> 在全混合動(dòng)力汽車上不再使用綜合起動(dòng)發(fā)電機(jī),取代它的是一個(gè)獨(dú)立的電動(dòng)馬達(dá)和交流發(fā)電機(jī)、起動(dòng)機(jī),這些裝置也可以起到綜合起動(dòng)發(fā)電機(jī)的作用。電動(dòng)馬達(dá)可以獨(dú)立驅(qū)動(dòng)汽車行駛,尤其是在城市道路上(走走停停)的行駛。能量?jī)?chǔ)存系統(tǒng)也得到了改進(jìn),這樣就提高了汽車純電動(dòng)續(xù)航能力,減少了發(fā)動(dòng)機(jī)的體積,從而提高燃油經(jīng)濟(jì)性和減少排放。與非混合動(dòng)力汽車相比,全混
89、合動(dòng)力汽車的燃油消耗量可以減少40%-50%。</p><p><b> 插電式混合動(dòng)力</b></p><p> 插電式混合動(dòng)力汽車在結(jié)構(gòu)上和全混合動(dòng)力汽車相似,不同的是插電式混合動(dòng)力汽車有一個(gè)比較大的能量?jī)?chǔ)存系統(tǒng),可以通過與外部電源連接進(jìn)行充電。在蓄電池儲(chǔ)存能量范圍內(nèi),可以通過電動(dòng)馬達(dá)來驅(qū)動(dòng)汽車行駛,但是當(dāng)蓄電池的能量降到一定水平后,其運(yùn)行形勢(shì)就和全混合動(dòng)力一
90、樣了。</p><p> 2.1.3再生制動(dòng)原理</p><p> 混合動(dòng)力電動(dòng)汽車最重要的特點(diǎn)是可以回收大量的制動(dòng)能量。在制動(dòng)過程中,電動(dòng)馬達(dá)可以作為發(fā)電機(jī)來運(yùn)行操作,將制動(dòng)過程中的動(dòng)能轉(zhuǎn)換為電能儲(chǔ)存到蓄電池中,這些電能就可以被汽車重復(fù)使用。但是,車輛的制動(dòng)性能就將影響到汽車的安全性。在緊急制動(dòng)狀態(tài)下,汽車的制動(dòng)距離要盡可能的短,還要保證制動(dòng)時(shí)汽車有較好的方向穩(wěn)定性。汽車具有較好的方
91、向穩(wěn)定性,就需要控制車輪的制動(dòng)力分配。</p><p> 一般來說,制動(dòng)時(shí)所需的制動(dòng)力矩比電動(dòng)馬達(dá)產(chǎn)生的制動(dòng)力矩大得多。因此,機(jī)械制動(dòng)系統(tǒng)需要和電子再生制動(dòng)系統(tǒng)同時(shí)存在,這就需要適當(dāng)?shù)脑O(shè)計(jì)以保證制動(dòng)時(shí)的操作穩(wěn)定性,不至于影響到汽車的安全性。</p><p><b> 制動(dòng)時(shí)能量消耗</b></p><p> 由公式可得,一個(gè)質(zhì)量為1500
92、Kg的汽車以100km/h初速度制動(dòng)到完全停止,需要消耗0.16kwh的動(dòng)能。</p><p> 如果這些能量的25%可以通過再生制動(dòng)系統(tǒng)進(jìn)行回收,當(dāng)忽略制動(dòng)和加速過程中的空氣阻力,機(jī)械摩擦和滾動(dòng)阻力,假設(shè)電動(dòng)馬達(dá)的工作效率100%,利用公式可以估算出,這些能量可以使汽車從0km/h加速到50km/h.這就表明,當(dāng)汽車行駛在城市道路上,汽車不停加速和制動(dòng),混合動(dòng)力電動(dòng)車的燃油經(jīng)濟(jì)性可以大大增加。需要注意的是,制
93、動(dòng)能量的回收量受到馬達(dá)的型號(hào)和能量轉(zhuǎn)換率的限制。</p><p> 2.1.4再生制動(dòng)系統(tǒng)</p><p> 目前,通常使用的有兩種再生制動(dòng)方法。這些方法通常稱為串聯(lián)再生制動(dòng)和并聯(lián)制動(dòng),每種制動(dòng)策略都有其優(yōu)點(diǎn)和缺點(diǎn),本文對(duì)此將進(jìn)行具體討論。</p><p><b> 并聯(lián)再生制動(dòng)</b></p><p> 在并聯(lián)
94、再生制動(dòng)系統(tǒng)中,電動(dòng)馬達(dá)和機(jī)械制動(dòng)系統(tǒng)同時(shí)工作,從而使汽車減速。因?yàn)闄C(jī)械制動(dòng)系統(tǒng)不能獨(dú)立的控制制動(dòng)力,使制動(dòng)時(shí)的能量轉(zhuǎn)換為熱能而不是電能,因此這不是最有效地再生制動(dòng)方法。但是并聯(lián)再生制動(dòng)結(jié)構(gòu)簡(jiǎn)單成本低,這就成為其一大優(yōu)勢(shì)。并聯(lián)再生制動(dòng)的機(jī)械制動(dòng)系統(tǒng)只需要稍加修改,而且電動(dòng)馬達(dá)的控制算法也可以很容易在汽車上實(shí)現(xiàn)。這種制動(dòng)方法還有一個(gè)額外的優(yōu)勢(shì),當(dāng)再生制動(dòng)系統(tǒng)發(fā)生故障時(shí),機(jī)械制動(dòng)系統(tǒng)可以起到備用的作用。</p><p&g
95、t;<b> 串聯(lián)再生制動(dòng)</b></p><p> 在串聯(lián)再生制動(dòng)中,電動(dòng)馬達(dá)只有在制動(dòng)時(shí)才起作用。只有當(dāng)電動(dòng)馬達(dá)和能量?jī)?chǔ)存系統(tǒng)無法接受更多制動(dòng)時(shí)所需的能量時(shí),再生制動(dòng)系統(tǒng)才起作用。串聯(lián)再生制動(dòng)需要獨(dú)立的控制制動(dòng)力矩,串聯(lián)再生制動(dòng)可以高效率的把動(dòng)能轉(zhuǎn)換為電能,這是其一項(xiàng)優(yōu)勢(shì)。但是它的不足之處在于,制動(dòng)系統(tǒng)結(jié)構(gòu)復(fù)雜,成本高。這種制動(dòng)方式需要制動(dòng)踏板模擬器,制動(dòng)系統(tǒng)也需要重新設(shè)計(jì),這都會(huì)增
96、加其制造成本。因?yàn)橹苿?dòng)系統(tǒng)需要裝有傳感器和信息處理器,這就會(huì)增加了結(jié)構(gòu)的復(fù)雜度。</p><p> 2.1.5目前的再生制動(dòng)系統(tǒng)</p><p> 目前大多數(shù)混合動(dòng)力電動(dòng)汽車的再生制動(dòng)系統(tǒng)都是比較昂貴的電液制動(dòng)系統(tǒng)。再生制動(dòng)系統(tǒng)使用制動(dòng)踏板模擬器來建立駕駛者的制動(dòng)需求,這個(gè)制動(dòng)踏板模擬器與液壓制動(dòng)電路獨(dú)立分開。這樣再將制動(dòng)需求按照一定比例轉(zhuǎn)換為再生制動(dòng)和機(jī)械制動(dòng)需求,然后將機(jī)械制動(dòng)需求
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