（注：本文是譯文，original author: S. Di Cairano, J. Doering）

We consider the speed control of a spark ignition engine during vehicle deceleration. When the torque converter bypass clutch is open the engine speed needs to be kept close to the turbine speed to guarantee responsiveness of the vehicle for subsequent accelerations. However, to maintain vehicle drivability, undesired crossing between engine speed and turbine speed must not occur, despite the presence of significant torque disturbances. Hence, the engine speed during vehicle decelerations needs to be precisely controlled by feedback control, which has to coordinate airflow and spark timing and enforce several constraints including engine stall avoidance, combustion stability, and actuator limits.
我們考慮了火花點(diǎn)火發(fā)動(dòng)機(jī)在車輛減速過(guò)程中的速度控制。當(dāng)液力變矩器旁路離合器打開(kāi)時(shí)，發(fā)動(dòng)機(jī)轉(zhuǎn)速需要保持接近渦輪轉(zhuǎn)速，以保證車輛對(duì)后續(xù)加速度的響應(yīng)性。然而，盡管存在顯著的轉(zhuǎn)矩?cái)_動(dòng)，為了保持車輛可駕駛性，不能發(fā)生非預(yù)期的發(fā)動(dòng)機(jī)轉(zhuǎn)速和渦輪速度交叉。因此，車輛減速期間的發(fā)動(dòng)機(jī)速度需要精確地通過(guò)反饋控制來(lái)控制，反饋控制必須協(xié)調(diào)氣流和火花正時(shí)，并避免發(fā)動(dòng)機(jī)失速、且滿足燃燒穩(wěn)定性和致動(dòng)器限制在內(nèi)的多個(gè)約束。

In today’s vehicles the powertrain control system is being continuously refined to improve fuel economy, emissions, safety, and drivability, thus making the vehicles more economical, sustainable, safe, and fun to drive. Drivability is the capability of the vehicle to be responsive and predictable to the driver’s commands. While good drivability often goes unnoticed by the driver, poor drivability may lead to low driver confidence in the vehicle.
在當(dāng)今的車輛中，動(dòng)力總成控制系統(tǒng)不斷完善，以提高燃油經(jīng)濟(jì)性、排放、安全性和駕駛性，從而使車輛更加經(jīng)濟(jì)、可持續(xù)、安全和駕駛樂(lè)趣。駕駛能力是車輛對(duì)駕駛員指令的響應(yīng)能力和可預(yù)測(cè)性。雖然良好的駕駛性能經(jīng)常不被駕駛員注意到，但駕駛性能差可能導(dǎo)致車輛駕駛員信心低。

For vehicles equipped with standard automatic transmissions, the drivability effects are noticeable during vehicle deceleration. When the vehicle is decelerating and the torque converter bypass clutch is open, the torque provided to the vehicle is related to the turbine-engine speed ratio [1]–[4], the ratio between the speeds of the engine and of the torque converter turbine, which is connected to the gearbox input shaft. In order to obtain a consistent behavior, to maintain vehicle responsiveness, and to achieve high fuel economy, the engine speed during deceleration has to be precisely controlled. In spark ignition (SI) engines such control is achieved by manipulating the airflow and the spark timing, which, however, are subject to several constraints, including limits imposed by combustion stability and engine breathing.
對(duì)于裝備有標(biāo)準(zhǔn)自動(dòng)變速器的車輛而言，在車輛減速過(guò)程中駕駛性能是顯著的。當(dāng)車輛減速和液力變矩器旁路離合器打開(kāi)時(shí)，提供給車輛的扭矩與渦輪發(fā)動(dòng)機(jī)速比，發(fā)動(dòng)機(jī)轉(zhuǎn)速和液力變矩器渦輪之間的比率有關(guān)，后者與變速箱輸入軸相連。為了獲得一致的行為，以保持車輛響應(yīng)性，并實(shí)現(xiàn)高燃料經(jīng)濟(jì)性，必須精確控制減速期間的發(fā)動(dòng)機(jī)速度。在火花點(diǎn)火（SI）發(fā)動(dòng)機(jī)中，這樣的控制是通過(guò)操縱氣流和火花正時(shí)來(lái)實(shí)現(xiàn)的，然而，它受到多個(gè)約束，包括由燃燒穩(wěn)定性和發(fā)動(dòng)機(jī)呼吸所施加的限制。

Model predictive control (MPC) systematically ad-dresses the problem of achieving multiple objectives while enforcing constraints on vehicle inputs and states. Thus, it has the potential of significantly simplifying design and calibration of multivariable control systems. Furthermore, the execution of MPC controllers at high rate and with low computing power can be achieved by using the explicit MPC feedback law.
模型預(yù)測(cè)控制（MPC）系統(tǒng)地提出了在實(shí)現(xiàn)車輛輸入和狀態(tài)約束的同時(shí)實(shí)現(xiàn)多個(gè)目標(biāo)的問(wèn)題。因此，它有可能大大簡(jiǎn)化多變量控制系統(tǒng)的設(shè)計(jì)和校準(zhǔn)。此外，通過(guò)使用顯式MPC反饋定律，可以實(shí)現(xiàn)高速率和低計(jì)算功率的MPC控制器的執(zhí)行。

A well known speed control problem in automotive is Idle Speed Control (ISC) [20]. In ISC the engine speed is regulated to a constant setpoint using throttle (or bypass valve, in older engines) and spark timing, while rejecting disturbances caused for instance by air-conditioning and power steering pump load. Since the setpoint remains mostly constant, ISC operates in very specific, and almost stationary, engine operating conditions. The challenges in ISC are the time delay in the airpath and the reduced and varying authority of the spark actuation.
眾所周知，汽車的速度控制問(wèn)題是怠速控制（ISC）〔20〕。在ISC中，使用節(jié)流閥（或旁通閥，在較舊發(fā)動(dòng)機(jī)中）和火花正時(shí)調(diào)節(jié)發(fā)動(dòng)機(jī)轉(zhuǎn)速，同時(shí)排除由空調(diào)和動(dòng)力轉(zhuǎn)向泵負(fù)載引起的干擾。由于設(shè)定點(diǎn)基本上保持恒定，ISC工作在非常具體的、幾乎靜止的發(fā)動(dòng)機(jī)運(yùn)行工況中。ISC面臨的挑戰(zhàn)是空氣路徑中的時(shí)間延遲和火花驅(qū)動(dòng)的減少和變化。

While similar in terms of manipulated and controlled variables, engine speed control during deceleration is significantly more challenging than ISC, since the controller operates across several engine operating conditions, i.e., speeds and loads. The controller has to track various reference profiles generated by the vehicle control system according to the type of deceleration (braking, coasting, creeping, etc.). Some reference profiles can be rapidly changing (e.g., during braking), while others may be almost constant (e.g., during creeping). In all these conditions the controller must track the reference profile with small error (e.g., less than 50rpm), to provide a smooth and predictable deceleration (i.e., consistent in repeated maneuvers), and to maintain vehicle responsiveness to subsequent accelerations while avoiding undesired lash crossing events. The engine deceleration controller needs to counteract the disturbances that affect the idle controller. In addition it has to regulate the engine speed after a gear-shift, to engage from transient conditions, and to respond to reference profiles changing with rates that may not be achievable.
雖然在操縱和控制變量方面相似，但減速期間的發(fā)動(dòng)機(jī)速度控制比ISC更具挑戰(zhàn)性，因?yàn)榭刂破髟诙鄠€(gè)發(fā)動(dòng)機(jī)操作條件下運(yùn)行，即速度和負(fù)載?？刂破鞅仨毟鶕?jù)減速的類型（制動(dòng)、滑行、爬行等）來(lái)跟蹤由車輛控制系統(tǒng)產(chǎn)生的各種參考輪廓。一些參考輪廓可以迅速改變（例如，在制動(dòng)期間），而其他參考輪廓幾乎是恒定的（例如，在爬行期間）。在所有這些條件下，控制器必須跟蹤具有較小誤差（例如小于50rPM）的參考輪廓，以提供平滑且可預(yù)測(cè)的減速，并保持車輛對(duì)后續(xù)加速度的響應(yīng)性，同時(shí)避免發(fā)生不希望的事件。發(fā)動(dòng)機(jī)減速控制器需要抵消影響怠速控制器的干擾。此外，它必須在換檔后調(diào)節(jié)發(fā)動(dòng)機(jī)轉(zhuǎn)速，以從瞬態(tài)條件出發(fā)，并響應(yīng)于可能無(wú)法實(shí)現(xiàn)的速率變化的基準(zhǔn)曲線。

The deceleration controller receives the powertrain state (engine speed, torque, etc.) from the vehicle sensors and estimators, and the desired engine speed and constraints from the vehicle control system. The controller commands the base torque, the maximum achievable indicated torque for the current airflow, and the torque ratio, the percentage of the base torque that is actually produced through spark modulation. The commanded base torque and the torque ratio are achieved by electronic throttle control and spark timing control implemented in lower level control functions that may exploit additional powertrain state variables, such as maximum brake torque (MBT) ignition angle [21], engine temperature, manifold pressure, etc. By this architecture, the engine deceleration control is decoupled from the actuator control, and hence the complexity of control design is reduced, and the resulting control system is modular.
減速控制器接收來(lái)自車輛傳感器和估計(jì)器的動(dòng)力傳動(dòng)系狀態(tài)（發(fā)動(dòng)機(jī)速度、扭矩等）以及來(lái)自車輛控制系統(tǒng)期望的發(fā)動(dòng)機(jī)速度和約束?？刂破骺刂苹巨D(zhuǎn)矩、當(dāng)前氣流的最大可實(shí)現(xiàn)指示轉(zhuǎn)矩和轉(zhuǎn)矩比，通過(guò)火花調(diào)制實(shí)際產(chǎn)生的基本轉(zhuǎn)矩的百分比。命令的基礎(chǔ)扭矩和扭矩比是通過(guò)電子節(jié)氣門控制和點(diǎn)火定時(shí)控制實(shí)現(xiàn)的，在下級(jí)控制功能中，可以利用額外的動(dòng)力傳動(dòng)系狀態(tài)變量，例如最大制動(dòng)扭矩（MBT）點(diǎn)火角（21），發(fā)動(dòng)機(jī)溫度，歧管。通過(guò)這種結(jié)構(gòu)，發(fā)動(dòng)機(jī)減速控制與執(zhí)行器控制解耦，從而降低了控制設(shè)計(jì)的復(fù)雜性，并且得到的控制系統(tǒng)是模塊化的。

In today’s SI engines the air-to-fuel ratio is tightly controlled to stoichiometry to maintain efficiency of the three-way catalyst which reduces emissions [22], and, as a consequence, it is not a manipulated variable for the engine deceleration control. Also, since it is tightly controlled to a constant value, the impact of air-to-fuel ratio fluctuations on the engine speed dynamics can be neglected [16].
在當(dāng)今的SI發(fā)動(dòng)機(jī)中，空氣燃料比被嚴(yán)格控制到化學(xué)計(jì)量以保持三效催化劑的效率，從而降低排放，因此，它不是用于發(fā)動(dòng)機(jī)減速控制的操縱變量。此外，由于它被嚴(yán)格控制到一個(gè)恒定值，空氣-燃料比波動(dòng)對(duì)發(fā)動(dòng)機(jī)速度動(dòng)力學(xué)的影響可以忽略。

The deceleration controller needs also to enforce constraints on state and control variables. The airflow cannot decrease below a minimum value, otherwise the combustion becomes unstable [21]. Similarly, an upper bound on the airflow has to be enforced, due to engine breathing conditions. Both these bounds vary significantly during deceleration. The torque ratio achieved by spark timing is also limited. Finally, the engine speed must be maintained above a given threshold designed conservatively to avoid engine stalls .
減速控制器還需要執(zhí)行對(duì)狀態(tài)和控制變量的約束。氣流不能降到最小值以下，否則燃燒變得不穩(wěn)定。類似地，由于發(fā)動(dòng)機(jī)的呼吸條件，氣流的上界必須被強(qiáng)制執(zhí)行。這兩個(gè)界限在減速過(guò)程中變化很大。通過(guò)點(diǎn)火正時(shí)實(shí)現(xiàn)的轉(zhuǎn)矩比也受到限制。最后，發(fā)動(dòng)機(jī)轉(zhuǎn)速必須保守設(shè)計(jì)讓其保持在給定的閾值以上，以避免發(fā)動(dòng)機(jī)熄火。

The design of classical controllers (e.g., PID-based) that achieve all these requirements can be cumbersome due to the need for selecting an appropriate logic to coordinate the control channels and to enforce saturation and anti-windup for dealing with the constraints. This may result in long development and calibration time and sub-optimal performance.
實(shí)現(xiàn)所有這些要求的經(jīng)典控制器（例如，基于PID）的設(shè)計(jì)可能是繁瑣的，因?yàn)樾枰x擇適當(dāng)?shù)倪壿媮?lái)協(xié)調(diào)控制信道，并執(zhí)行飽和和反飽和處理約束。這可能導(dǎo)致很長(zhǎng)的開(kāi)發(fā)和校準(zhǔn)時(shí)間和次優(yōu)性能。