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車輛工程專業(yè)畢業(yè)論文 外文翻譯1

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1、 車輛工程專業(yè)畢業(yè)論文 外文翻譯1 Drive force control of a parallel-series hybrid system Abstract Since each component of a hybrid system has its own limit of performance, the vehicle power depends on the weakest component. So it is necessary to design the balance of the components. The vehicle must be con

2、trolled to operate within the performance range of all the components. We designed the specifications of each component backward from the required drive force. In this paper we describe a control method for the motor torque to avoid damage to the battery, when the battery is at a low state of charge

3、. Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V. All rights reserved. 1. Introduction In recent years, vehicles with internal combustion engines have increasingly played an important role as a means of transportation, and are contributing much to the development of soc

4、iety. However, vehicle emissions contribute to air pollution and possibly even global warming, which require effective countermeasures. Various developments are being made to reduce these emissions, but no further large improvements can be expected from merely improving the current engines and trans

5、missions. Thus, great expectations are being placed on the development of electric, hybrid and natural gas-driven vehicles. Judging from currently applicable technologies, and the currently installed infrastructure of gasoline stations, inspection and service facilities, the hybrid vehicle, driven b

6、y the combination of gasoline engine and electric motor, is considered to be one of the most realistic solutions. Generally speaking, hybrid systems are classified as series or parallel systems. At Toyota, we have developed the Toyota Hybrid System (hereinafter referred to as the THS) by combining

7、the advantages of both systems. In this sense the THS could be classified as a parallel-series type of system. Since the THS constantly optimizes engine operation, emissions are cleaner and better fuel economy can be achieved. During braking, Kinetic energy is recovered by the motor, thereby reducin

8、g fuel consumption and subsequent CO2 emissions. Emissions and fuel economy are greatly improved by using the THS for the power train system. However, the THS incorporates engine, motor, battery and other components, each of which has its own particular capability. In other words, the driving force

9、 must be generated within the limits of each respective component. In particular, since the battery output varies greatly depending on its level of charge, the driving force has to be controlled with this in mind. This report clarifies the performance required of the respective THS components based

10、 on the driving force necessary for a vehicle. The method of controlling the driving force, both when the battery has high and low charge, is also described. 2. Toyota hybrid system (THS) [1,2] As Fig. 1 shows, the THS is made up of a hybrid transmission, engine and battery. 2.1. Hybrid tra

11、nsmission The transmission consists of motor, generator, power split device and reduction gear. The power split device is a planetary gear. Sun gear, ring gear and planetary carrier are directly connected to generator, motor and engine, respectively. The ring gear is also connected to the reduction

12、 gear. Thus, engine power is split into the generator and the driving wheels. With this type of mechanism, the revolutions of each of the respective axes are related as follows. Here, the gear ratio between the sun gear and the Fig. 1. Schematic of Toyota hybrid system (THS). ring

13、gear is ρ : where Ne is the engine speed, Ng the generator speed and Nm the motor speed. Torque transferred to the motor and the generator axes from the engine is obtained as follows: where Te is the engine torque. The drive shaft is connected to the ring gear via a re

14、duction gear. Consequently, motor speed and vehicle speed are proportional. If the reduction gear ratio isη, the axle torque is obtained as follows: where Tm is the motor torque. As shown above, the axle torque is proportional to the total torque of the engine and the motor on the mot

15、or axis. Accordingly, we will refer to motor axis torque instead of axle torque. 2.2. Engine A gasoline engine having a displacement of 1.5 l specially designed for the THS is adopted [3]. This engine has high expansion ratio cycle, variable valve timing system and other mechanisms in order to

16、improve engine efficiency and realize cleaner emissions. In particular, a large reduction in friction is achieved by setting the maximum speed at 4000 rpm (=Ne max). 2.3. Battery As sealed nickel metal hydride battery is adopted. The advantages of this type of battery are high power density and

17、 long life. this battery achieves more than three times the power density of those developed for conventional electric vehicles [4]. 3. Required driving force and performance The THS offers excellent fuel economy and emissions reduction. But it must have the ability to output enough driving

18、force for a vehicle. This section discusses the running performance required of the vehicle and the essential items required of the respective components. Road conditions such as slopes, speed limits and the required speed to pass other vehicles determine the power performance required by the vehic

19、le. Table 1 indicates the power performance needed in Japan. 3.1. Planetary gear ratioρ The planetary gear ratio (ρ) has almost no effect on fuel economy and/or emissions. This is because the required engine power (i.e. engine condition) depends on vehicle speed, driving force and battery condi

20、tion, and not on the planetary gear ratio. Conversely, it is largely limited by the degree of installability in the vehicle and manufacturing aspects, leaving little room for design. In the currently developed THS, ρ=0.385. 3.2. Maximum engine power Since the battery cannot be used for cruising

21、 due to its limited power storage capacity, most driving is reliant on engine power only. Fig. 2 shows the power required by a vehicle equipped with the THS, based on its driving resistance. Accordingly, the power that is required for cruising on a level road at 140 km/h or climbing a 5% slope at 10

22、5 km/h will be 32 kW. If the transmission loss is taken into account, the engine requires 40 kW (=Pe max) of power. The THS uses an engine with maximum power of 43 kW in order to get good vehicle performance while maintaining good fuel economy. 3.3. Maximum generator torque

23、 As described in Section 2, the maximum engine speed is 4000 rpm (=Ne max). To attain maximum torque at this speed, maximum engine torque is obtained as follows: From Eq. (3), the maximum torque on the generator axis will be as follows: This is the torque at which the

24、generator can operate without being driven to over speed. Actually, higher torque is required because of acceleration/deceleration of generator speed and dispersion of engine and/or generator torque. By adding 40% torque margin to the generator, the necessary torque is calculated as follo

25、ws: 3.4. Maximum motor torque From Fig. 3, it can be seen that the motor axis needs to have a torque of 304 Nm to acquire the 30% slope climbing performance. This torque merely balances the vehicle on the slope. To obtain enough starting and accelerating performance, it is necessary to have add

26、itional torque of about 70 Nm, or about 370 Nm in total. From Eq. (2), the transmitted torque from the engine is obtained as follows: Consequently, a motor torque of 300 Nm (=Tm max) is necessary. 3.5. Maximum battery power As Fig. 2 shows, driving power of 49 kW is needed for c

27、limbing on a 5%slope at 130 km/h. Thus, the necessary battery power is obtained by subtracting the engine-generated power from this. As already discussed, if an engine having the minimum required power is installed, it can only provide 32 kW of power, so the required battery power will be 17 kW. If

28、the possible loss that occurs when the battery supplies power to the motor is taken into account, battery power of 20 kW will be needed. Thus, it is necessary to determine the battery capacity by targeting this output on an actual slope. Table 2 lists the required battery specifications. Table 3 su

29、mmarizes the specifications actually adopted by the THS and the requirements determined by the above discussion. The required items represent an example when minimum engine power is selected. In other words, if the engine is changed, each of the items have to be changed accordingly.

30、 4. Driving force control The THS requires controls not necessary for conventional or electric vehicles in order to control the engine, motor and generator cooperatively. Fig. 4 outlines the control system. Fig. 4. Control diagram of the THS. Inputs of control system are accelerator

31、 position, vehicle speed (motor speed), generator speed and available battery power. Outputs are the engine-required power, generator torque and motor torque. First, drive torque demanded by the driver (converted to the motor axis) is calculated from the accelerator position and the vehicle speed.

32、The necessary drive power is calculated from this torque and the motor speed. Required power for the system is the total of the required drive power, the required power to charge the battery and the power loss in the system. If this total required power exceeds the prescribed value, it becomes requi

33、red engine power. If it is below the prescribed value, the vehicle runs on the battery without using the engine power. Next, the most efficient engine speed for generating engine power is calculated; this is the engine target speed. The target speed for the generator is calculated using Eq. (1) with

34、 engine target speed and motor speed. The generator torque is determined by PID control. Engine torque can be calculated in reverse by using Eq. (3) and the torque transferred from the engine to the motor axis can be calculated from (2). The motor torque is obtained by subtracting this torque from t

35、he initially calculated drive torque. Since it is not possible to produce a torque whereby the motor consumption power exceeds the total of the generator-generated power and the power supplied by the battery, it is necessary to control the motor power (torque) within this total power. Fig. 5 shows t

36、he control method. The sum of the power form the generator and the available battery power become the power that can be used by the motor. The available motor torque can be obtained by dividing this combined power by the motor speed. When the motor speed is low, if the calculated motor torque exceed

37、s the motor specification of torque the motor torque is determined by the specification. By controlling the motor torque requirement with this limited torque, the motor consumption power can be controlled to within the available power. If the available battery power is large enough, the available mo

38、tor torque hardly limits the motor torque. Conversely, when the charge is low, the motor torque is frequently limited. Fig. 6 shows the respective maximum drive torque of the battery, the engine, and the engine plus the battery while running based on the controls above, when the THS has the compone

39、nts as specified in Section 3. 5. Conclusions This paper discussed the control of drive power in the Toyota Hybrid System. The following conclusions were obtained: l l The performance required for each component can be determined by reversely calculating power perfo

40、rmance required for a vehicle. The available battery power varies according to its state of charge. However, by limiting the motor torque, the battery power can be controlled to within the battery’s available power. 混合動(dòng)力系統(tǒng)驅(qū)動(dòng)力的串并聯(lián)控制 摘要 由于混合動(dòng)力系統(tǒng)的每個(gè)部分都有自己的極限性能,所以汽車動(dòng)力取決于最脆弱的哪一個(gè)組成部分。因此,有必要對各個(gè)部件進(jìn)行

41、平衡設(shè)計(jì)。因?yàn)檐囕v必須在所有部件的控制范圍混合動(dòng)力傳動(dòng)系統(tǒng) 混合動(dòng)力傳動(dòng)系統(tǒng)由發(fā)動(dòng)機(jī)、發(fā)電機(jī)、動(dòng)力分配裝置和減速器組成。動(dòng)力分配裝置是一個(gè)行星齒輪機(jī)構(gòu)。太陽輪、齒圈和行星架分別直接連接到發(fā)電機(jī)、電動(dòng)機(jī)和發(fā)動(dòng)機(jī),齒圈也直接連接到減速器。因此,發(fā)動(dòng)機(jī)的動(dòng)力被分配到發(fā)電機(jī)和驅(qū)動(dòng)輪。使用這種機(jī)械裝置,各軸的轉(zhuǎn)速有以下關(guān)系。在這里,太陽輪和齒圈之間的傳動(dòng)比是ρ: 這里,Ne是發(fā)動(dòng)機(jī)的轉(zhuǎn)速,Ng是發(fā)電機(jī)的轉(zhuǎn)速,Nm是電動(dòng)機(jī)的轉(zhuǎn)速。 Fig. 1. Schematic of Toyota hybrid system (THS). 傳遞到電動(dòng)機(jī)的

42、轉(zhuǎn)矩和發(fā)電機(jī)從發(fā)動(dòng)機(jī)獲得的轉(zhuǎn)矩如下: 這里,Te是發(fā)動(dòng)機(jī)的輸出轉(zhuǎn)矩。 驅(qū)動(dòng)軸通過減速器連接到齒圈,因此,車連行駛速度與電機(jī)轉(zhuǎn)速成正比。如果減速器的減速比為η,則驅(qū)動(dòng)軸獲得的扭矩如下式: 這里Tm為電動(dòng)機(jī)速出扭矩。 如上式所示,驅(qū)動(dòng)軸獲得的扭矩與發(fā)動(dòng)機(jī)和電動(dòng)機(jī)軸上輸出的總扭矩成正比。因此,我們會(huì)參考電動(dòng)機(jī)軸輸出扭矩而不是驅(qū)動(dòng)軸上獲得的扭矩。 2.2. 發(fā)動(dòng)機(jī) 豐田混合動(dòng)力系統(tǒng)采用專門設(shè)計(jì)的排量為1.5L的汽油發(fā)動(dòng)機(jī)。為了提高發(fā)動(dòng)機(jī)的效率、實(shí)現(xiàn)情節(jié)的排放,這臺(tái)發(fā)動(dòng)機(jī)采用了高膨脹率循環(huán)、可變相位配氣系統(tǒng)以及其他機(jī)構(gòu)。特別是實(shí)現(xiàn)了轉(zhuǎn)速為4

43、000r/min(最高轉(zhuǎn)速)時(shí)最大限度的減少了摩擦力。 2.3.電池 電池是采用了密封鎳金氫化物電池。這種電池的優(yōu)點(diǎn)是功率密度高、壽命長。這種電池的功率密度可以達(dá)到3倍以上常規(guī)電動(dòng)車開發(fā)的電池。 3. 驅(qū)動(dòng)力和性能要求 豐田混合動(dòng)力系統(tǒng)提供了有意的燃油經(jīng)濟(jì)性和廢氣排放,但是它必須還要具備足夠的車輛動(dòng)力輸出要求。本節(jié)討論車輛運(yùn)動(dòng)性能要求以及各組件的基本要求。 汽車的動(dòng)力性能由通過的道路條件(如斜坡)、車速限制、所需超車速度等來確定。表.1所示為在日本汽車行駛的動(dòng)力性能要求。 3.1. 行星排特性參數(shù) 行星排特性參數(shù)ρ對車輛燃油經(jīng)濟(jì)性或排量幾

44、乎沒有影響。這是因?yàn)椋囕v的行駛速度、驅(qū)動(dòng)力和電池條件取決于所需發(fā)動(dòng)機(jī)功率(即發(fā)動(dòng)機(jī)狀態(tài)),而不是行星排特性參數(shù)。相反,他很大程度上受限制于車輛的總體布置預(yù)留的設(shè)計(jì)空間。目前在先進(jìn)的豐田混合動(dòng)力系統(tǒng)ρ=0.385。 3.2. 最大發(fā)動(dòng)機(jī)功率 由于電池存儲(chǔ)容量的限制,其使用范圍不能超出其限制范圍。大部分驅(qū)動(dòng)力是僅僅依靠發(fā)動(dòng)機(jī)提供的能量。圖.2所示基于本田混合動(dòng)力系統(tǒng)的車輛行駛阻力對車輛動(dòng)力的規(guī)格要求。相應(yīng)地,車輛以140km/h的速度行駛在平整的公路上或以105km/h的速度在坡度為5%坡道上行駛所需要的功率為32kw。如果考慮傳動(dòng)系的損失在內(nèi),就需要發(fā)動(dòng)機(jī)提供40kw的功率。為了在保

45、持良好的燃油經(jīng)濟(jì)性的同時(shí)得到良好的車輛動(dòng)力性能,豐田混合動(dòng)力系統(tǒng)采用最大功率為43kw的發(fā)動(dòng)機(jī)。 3.3. 發(fā)電機(jī)最大扭矩 如第二節(jié)所述,發(fā)動(dòng)機(jī)最高轉(zhuǎn)速為4000r/min,要達(dá)到這一轉(zhuǎn)速是的最大扭矩從發(fā)動(dòng)機(jī)獲得的最大扭矩如下: 根據(jù)式(3),作用在發(fā)電機(jī)上的最大扭矩如下: 這是在不超速行駛的情況下驅(qū)動(dòng)發(fā)電機(jī)運(yùn)轉(zhuǎn)的扭矩。實(shí)際上需要跟大的扭矩,因?yàn)榘l(fā)電機(jī)的加速或加速以及發(fā)電機(jī)扭矩的分散。因此要增加40%的扭矩作用在發(fā)電機(jī)上,所需扭矩計(jì)算如下: 3.4. 電動(dòng)機(jī)輸出最大扭矩 從圖

46、.3中可以看出,為了獲得30%的爬坡性能,電動(dòng)機(jī)需要提供304Nm的扭矩。這個(gè)扭矩僅僅是為了平衡車輛的坡道阻力,要獲得足夠的啟動(dòng)和加速性能,需要額外提供70Nm的扭矩或提供總扭矩為370Nm。 根據(jù)式(2),從發(fā)動(dòng)機(jī)傳輸傳輸?shù)呐ぞ乜梢酝ㄟ^下面計(jì)算獲得: 因此,電動(dòng)機(jī)必須能夠提供300Nm的最大扭矩。 3.5. 電池的最大功率 如圖.2所示,當(dāng)車輛以130km/h的速度爬上坡度為5%的斜坡時(shí)需要提供49kw的功率。因此減去發(fā)動(dòng)機(jī)提供的功率剩下的就是電池所要提供的功率。正如前面所述,如果安裝了小功率的發(fā)動(dòng)機(jī),它僅能提供32kw的功率,剩下所需的17kw的功率

47、需要由電池來供應(yīng)。如果將可能發(fā)生的損失考慮在內(nèi)的話,電池需要提供20kw的功率。因此,有必要針對實(shí)際的坡道通過能力來確定電池的供電能力要求。表.2列出了所需要的電池規(guī)格。 表.3概括了在上述討論的情況下實(shí)際采用的電池規(guī)格要求。所需的項(xiàng)目為實(shí)例時(shí)選擇了最小的發(fā)動(dòng)機(jī)功率,換句話說,如果發(fā)動(dòng)機(jī)做了更改則每個(gè)項(xiàng)目都要進(jìn)行相應(yīng)的更改。 4. 驅(qū)動(dòng)力控制 為了控制發(fā)動(dòng)機(jī)、電動(dòng)機(jī)以及發(fā)電機(jī)之間的合作,豐田混合動(dòng)力系統(tǒng)采用了常規(guī)汽車或電動(dòng)汽車所不必?fù)碛械目刂葡到y(tǒng)。圖.4列出了控制系統(tǒng)圖。 Fig. 4. Control diagram of th

48、e THS. 加速踏板位置、車輛行駛速度(電動(dòng)機(jī)轉(zhuǎn)速)、發(fā)電機(jī)轉(zhuǎn)速以及電池可用電量的相關(guān)參數(shù)均作為變量輸入到控制系統(tǒng)。輸出參數(shù)有所需發(fā)動(dòng)機(jī)功率、發(fā)電機(jī)輸入扭矩、電動(dòng)機(jī)輸出扭矩。首先,驅(qū)動(dòng)力矩由驅(qū)動(dòng)程序依據(jù)加速踏板位置和車輛行駛速度計(jì)算確定。所需要的驅(qū)動(dòng)功率是通過當(dāng)時(shí)的扭矩和電動(dòng)機(jī)轉(zhuǎn)速計(jì)算獲得。系統(tǒng)系統(tǒng)所需的動(dòng)力是所需驅(qū)動(dòng)力、電池充電所需動(dòng)力以及系統(tǒng)動(dòng)力損失動(dòng)力的和。如果所需的總功率超過預(yù)定值,它將成為所需的發(fā)動(dòng)力功率。如果低于預(yù)定值,車輛依靠電池功能而無需使用發(fā)動(dòng)機(jī)。其次,發(fā)動(dòng)機(jī)最高性能轉(zhuǎn)速下產(chǎn)生的能量是由計(jì)算得到,這時(shí)發(fā)動(dòng)機(jī)的目標(biāo)轉(zhuǎn)速。目標(biāo)速度是利用發(fā)動(dòng)機(jī)的目標(biāo)轉(zhuǎn)速和電動(dòng)機(jī)轉(zhuǎn)速利用式

49、(1)計(jì)算得到。發(fā)電機(jī)輸入轉(zhuǎn)矩由PID控制確定。發(fā)動(dòng)機(jī)輸出扭矩可由式(3)計(jì)算得到。電動(dòng)機(jī)輸出扭矩由最初計(jì)算的驅(qū)動(dòng)力矩減 去發(fā)動(dòng)機(jī)輸出扭矩得到。因?yàn)殡妱?dòng)機(jī)產(chǎn)生扭矩所消耗的能量不可能超過依靠發(fā)電機(jī)和電池同時(shí)供應(yīng)的能量,所以有必要將電動(dòng)機(jī)的功率限制在發(fā)電機(jī)和電池供用的總功率范圍內(nèi),圖.5示意了控制方法。發(fā)電機(jī)的輸出功率和電池供應(yīng)的有效功率之和是可以被電動(dòng)機(jī)利用的功率。電動(dòng)機(jī)輸出的有效扭矩可以根據(jù)電動(dòng)機(jī)轉(zhuǎn)速和總功率供應(yīng)來獲得。當(dāng)電動(dòng)機(jī)轉(zhuǎn)速低時(shí),如果計(jì)算扭矩超過電動(dòng)機(jī)的規(guī)格就由電動(dòng)機(jī)規(guī)格來確定。通過這有限的扭矩來控制電動(dòng)機(jī)的扭矩輸出要求,電動(dòng)機(jī)的功率消耗可以被控制在有效功率范圍內(nèi)。如果電池的有效功率足夠大,電動(dòng)機(jī)輸出地有效扭矩幾乎不再限制電動(dòng)機(jī)的扭矩輸出。與此相反,如果電池電量很低時(shí),電動(dòng)機(jī)的輸出扭矩就會(huì)經(jīng)常被限制。 圖.6顯示了當(dāng)豐田混合動(dòng)力系統(tǒng)被分割成只有電池供能、只有發(fā)動(dòng)機(jī)供能以及發(fā)動(dòng)機(jī)和電池同時(shí)供能三種情況是各自所能提供的最大驅(qū)動(dòng)力矩。 5. 結(jié)論 l 每個(gè)組件的性能要求是通過對車輛動(dòng)力性要求進(jìn)行反計(jì)算獲得。 l 電池的有效功率因電池的狀態(tài)而異。但是,通過對電動(dòng)機(jī)輸出扭矩的限制, 電池供應(yīng)功率可以被控制在電池功率的有效利用利用范圍內(nèi)。

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