Browse Topic: Transmission control units
Transmission tuning involves adjusting parameters within a vehicle's transmission control unit (TCU) or transmission control module (TCM) to optimize performance, efficiency, and driving experience. Transmission tuning is beneficial for optimizing performance, improving fuel efficiency, smoother shifting and enhancing drivability particularly when a vehicle's power output is increased or for specific driving conditions. Especially in offroad and agricultural machines, transmission tuning is vital to significantly improve vehicle performance during different operations. The process of transmission tuning is quite time consuming as multiple tuning iterations are required on the actual vehicle. A significant reduction in tuning time can be achieved using a simulation environment, which can mimic the actual vehicle dynamics and the real time vehicle behavior. In this paper, tuning during the forward and reverse motion of the tractor is described. A two-level PI control-based shift strategy
Evaluating the impact of software changes on fuel consumption and emissions is a critical aspect of transmission development. To evaluate the trade-offs between performance improvements and potential negative effects on efficiency, a forward-looking Software-in-the-Loop (SiL) simulation has been developed. Unlike backward calculations that derive fuel consumption based solely on cycle speed and engine speed, this approach executes complete driving cycles as the Worldwide Harmonized Light-Duty Vehicle Test Cycle (WLTC) within a detailed SiL environment. By considering all relevant influencing factors in a dynamic simulation, the method provides a more accurate assessment of fuel consumption and emission differences between two versions of the transmission software. The significant contribution of this work lies in the high-fidelity integration of a real virtual Transmission Control Unit (vTCU) software within a comprehensive, validated forward-looking SiL environment. This approach
This paper describes an optimal control method utilizing a Linear Quadratic Regulator (LQR) to control the torque during the gear shift on a multispeed electrified transmission to optimize for clutch actuator durability and shift performance. The dynamic state-space model of the system has been obtained using System-Identification. An LQR controller is formulated to minimize driveline oscillations and transmission-input-torque using the model by manipulating the electrical torque applied by the traction motor at the transmission input. The LQR controller is implemented in a simulation framework wherein the impact of vehicle parameters on the shift quality metrics is also assessed. Subjective and objective requirements are considered in the tuning process for the LQR controller. The LQR controller is utilized to generate profiled torque table calibrations. These calibrations are then deployed onto a production ready Transmission Control Unit and experimentally validated on a Class-8
The purpose of this SAE Recommended Practice is to provide a common electrical and mechanical interface specification that can be used to design electronic accelerator pedal position sensors and electronic control systems for use in medium- and heavy-duty vehicle applications.
During the vehicle launch (i.e. moving the vehicle from “0” speed), the clutch would be slowly engaged by the Driver or Transmission Control Unit (in Automatic Transmission/Automatic Manual Transmission vehicle) for smooth torque transfer between engine and transmission. The clutch is designed to transfer max engine torque with min heat generation. During the clutch engagement, the difference in flywheel and gearbox input shaft speed is called the clutch slipping phase which then leads to a huge amount of energy being dissipated in terms heat due to friction. As a result, clutch surface temperature increases consistently, when the surface temperature crosses the threshold limit, the clutch wears out quickly or burns spontaneously. Hence it is crucial to predict the energy dissipation and temperature variation in various components of clutch assembly through virtual simulation. During the development process of the vehicle, the clutch is tested over many duty cycles to ensure the
The eHorizon unit enables the possibility to get information of the road ahead in a defined prediction horizon. This data, like road gradient, curve radius, velocity limitation and road class, can be used by the onboard transmission control unit (TCU) via Controller Area Network (CAN) bus. This obtained predictive road information combined with the actual driving conditions can be used to optimize the shifting strategy by a model predictive control (MPC) algorithm which intends to reduce the fuel consumption. In order to solve the optimum problem inside the MPC with less memory, a pre-optimization based dynamic programming (PODP) approach is proposed. In this paper, the predictive gear selection (PGS) strategy will be compared to a conventional automatic gear shifting strategy in a simulation environment and validated on road by implementing it on a heavy-duty truck with a 16-speed automated manual transmission (AMT).
This SAE standard describes alternator physical, performance, and application requirements for heavy-duty electrical charging systems for off-road work machines, including those defined in SAE J1116.
With increased vehicular traffic density a trend has been observed where customers have started preferring automatic transmission in place of its manual version. This Automatic transmission not only shifts the gear automatically, with the help of sensors and actuators, but they are also tuned for better performance of the vehicle in terms of fuel efficiency and emission. This all comes at the cost of power consumption from the battery, increment in cost, weight and complexity. The main parts of an automatic transmission include Torque Convertor, Sensors, Actuators, Transmission Control Unit (TCU) with the epicyclic gear-train being the heart of it. In terms of use in the automotive, a system of epicyclic gear-train can provide only 2 gear ratios. Ravigneaux gear-train is the modified version of epicyclic gear-train where there are two set of Planet gears and Sun gears or Ring gears thereby capable of giving 4 gear ratios with a single system. This paper discusses the design analysis
This paper describes an approach to reduce development costs and time by frontloading of engineering tasks and even starting calibration tasks already in the early component conception phases of a vehicle development program. To realize this, the application of a consistent and parallel virtual development and calibration methodology is required. The interaction between vehicle subcomponents physically available and those only virtually available at that time, is achieved with the introduction of highly accurate real-time models on closed-loop co-simulation platforms (HiL-simulators) which provide the appropriate response of the hardware components. This paper presents results of a heterogeneous testing scenario containing a real internal combustion engine on a test facility and a purely virtual vehicle using two different automatic transmission calibration and hardware setups. The first constellation is based on an already validated vehicle model (A), including a physical dual-clutch
The mechanical properties of sandy road are quite different from those of hard surface road. For vehicle control systems such as EMS (engine management system), TCU (transmission control unit) and ABS (antilock brake system), the strategies and parameters set for solid surface road are not optimal for driving on sandy road. It is an effective way to improve the mobility of all-terrain vehicles by identifying sandy road online and shifting the control strategies and parameters of control systems to sandy sets. In this paper, a sandy road identification algorithm for SUVs is proposed. Firstly, the vehicle signals, such as engine torque and speed, gear position, wheel and vehicle speed, are acquired from EMS, TCU and ESP (electronic stability program) through CAN (controller area network) bus respectively. Based on the information and longitudinal force equilibrium equation, the travelling resistance of vehicle is estimated. The hydraulic torque converter is divided into several parts to
Shift selection devices are desired to be flexible for design and layout, in order to realize the next generation of cockpits for Lexus vehicles. In addition, refined shift operation feelings are also required to be suitable for Lexus vehicles. To meet these demands, the Lexus LC500 has been equipped with a shift-by-wire system, which replaces the mechanical linkage between the shift selector and transmission with electrical signals and an actuator. This shift-by-wire system will be installed in a wide variety of Lexus powertrain lineup, including conventional gas vehicles and hybrid vehicles. Therefore, the next generation shift-by-wire system for Lexus has been developed with high reliability and applicability. This technology will be essential when autonomous driving and autonomous parking systems are realized in the near future. To enable shifting of the parking mechanism in a simple configuration regardless of the engine operation state, shifting of the parking mechanism is
In this investigation an innovative signal generator will be introduced, which enables the generation of transient control signals for the gearshift process. The signals are generated merely depending on scalar transmission control unit (TCU) calibration parameters. The signal generator replaces the comprehensive TCU software within the simulation environment. Thus no extensive residual bus simulation is required. Multiple experimental models represent the core part of the signal generator. To predict the system behavior of the underlying system, the models are trained using measured data from a powertrain with automatic transmission mounted on a test rig. The results demonstrate that the introduced signal generator is suitable to predict transient control signals for the gearshift operation accurately. In combination with an additional powertrain model it is possible to simulate the gearshift process and subsequently to evaluate the gearshift comfort. The signal generator allows a
In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock. In addition, it can also avoid backward sliding and engine over-speed effectively
A control oriented model of a Dual Clutch Transmission was developed for real time Hardware In the Loop (HIL) applications. The model is an innovative attempt to reproduce the fast dynamics of the actuation system maintaining a step size large enough for real time applications. The model comprehends a detailed physical description of hydraulic circuit, clutches, synchronizers and gears, and simplified vehicle and internal combustion engine sub-models; a stable real time simulation is achieved with a simplification of the model without losing physical validity. After an offline validation, the model was implemented in a HIL system and connected to the TCU (Transmission Control Unit) via two input-output boards, and to a load plate which comprehends all the actuators. The paper presents a selection of the several tests that have been performed for the development of the DCT controller: electrical failure tests on sensors and actuators, mechanical failure tests on hydraulic valves
The demand for better driving comfort, fuel efficiency and reduced CO2 output has been becoming increasingly stringent. In response to such needs, we developed Transmission Electro-Hydraulic Control Module (TEHCM). For Automatic Transmission, expanding the lock-up control area is necessary to improve fuel efficiency. Meanwhile, lock-up control at lower speeds aggravates shift quality. To improve shift quality, Automatic Transmission Fluid (ATF) pressure control must be precise is needed. This can be accomplished by compensating for deviation in TEHCM, which integrates Transmission Control Unit (TCU) and the pressure control actuator, Variable Force Solenoid (VFS). However, there are two problems in installing TEHCM in compact vehicle. The first problem is the miniaturization of such TEHCM. Regarding modules that require a high electrical current to operate the VFS, thermal conductivity contradicts miniaturization. We applied a half-mold structure for TCU to accomplish high thermal
Dual Cultch Transmission (DCT) system has advantage both manual transmission and automatic transmission. As requirement of developing the DCT system is increasing, it is getting important to implement efficient On-Board Diagnosis (OBD) logic system to detect malfunction in vehicle to satisfy California Code Regulation (CCR 1968.2). To satisfy the CCR 1968.2, monitoring for circuit continuity and circuit faults shall be conducted continuously to detect Short to Circuit Ground (SCG), short to Circuit Battery (SCB) and Open error. In this paper, diagnostic logic for two clutches (clutch 1 and 2) and select, shift motor will be introduced to implement Transmission Control Unit (TCU) in DCT system. There are two methods to detect motor u/v/w-lines error. One is by using Application Specific Integrated Circuit (ASIC) diagnosis result and the other one is by software algorithm. Regarding diagnostic logic implemented in software algorithm, it will be derived by relationship between control
This SAE document describes alternator physical, performance and application requirements for heavy-duty electrical charging systems for off road work machines including those defined in SAE J1116.
The battery electric vehicle (BEV) equipped with automatic mechanical transmission (AMT) can realize gear-shifting automatically based on the optimal shift schedule and thereby gains higher economy and dynamics performances as well as easy drivability. As one of electronic control systems in BEV, the AMT control system takes charge of drivetrain control and plays an important role. However, nowadays the development of electronic control systems in automobile industry is facing a variety of challenges which mainly arise from complex functional requirements and market pressure, and it's the same to the development of AMT control system. This paper presents a multi-layered and modular design approach for the development of AMT control system in a battery electric bus. The multi-layered design approach divides system into two high-level layers, each of which is then divided into a number of low-level layers. One high-level layer is the basic driver layer which is responsible for TCU
For efficiency improvements, the desire to reduce the mass of vehicle subsystems is far greater than the ability. As a result, off-highway suppliers must seek innovation and technological advances through other means. Given their sheer size and resulting weight, it is easy to see why losing a few pounds from a combine, dump truck, or track loader would not really help the overall mass of the vehicle. Given this conundrum, while a lightweight, compact off-highway vehicle may be the dream, in reality, the road to efficiency gains is not as straightforward. “Building an axle is not like a recipe,” said Michele Lazzaro, Director at Dromos, the Italian manufacturer of transmissions, drive axles, and suspensions for numerous industrial markets. “Axles or associated components need to be developed harmonically, not through a modular concept. You need an optimized solution, and the key to optimizing the weight is making the best use of the material possible. This means that when you look at
A researcher from the Southwest Research Institute focuses on one of the most immediate and dramatic changes of powertrain design: the introduction of CVTs. The automotive drivetrain, after evolving little over the past 75 years, is undergoing a rapid and unprecedented metamorphosis. In light of the required reduction in fuel consumption and emissions levels set by legislation and reinforced by the reality of diminishing worldwide oil supplies, this accelerated transformation likely will continue for the next 20 years. Highlighting this transformation is the introduction of the continuously variable transmission (CVT), the change to 42-V electric systems, the introduction of hybrid-electric systems, and the electrification of many mechanical systems. According to researchers from the Southwest Research Institute, to fully realize the benefits of a CVT-configured powertrain, automotive engineers need to design engines with dramatically different operating and physical characteristics
The new Mercedes-Benz SL moves into the 21st century with an industry-first production electrohydraulic braking system and a next-generation folding hardtop. Technology is the design ethic that has produced the new-generation Mercedes-Benz SL, just as it was with the first direct-fuel-injection gullwing SL of the early 1950s. But the latest Mercedes-Benz, the fifth-generation SL, reaches far higher levels of sophistication, with the introduction of an electrohydraulic brake-by-wire system (claimed as a “first” for a road car), advanced folding hardtop, and a structure with high aluminum content. Engine developments slated for production are believed to include a bi-turbo V12, and Mercedes-AMG is already offering a 5.5-L supercharged V8 producing 350 kW (470 hp). It is half a century since Mercedes embarked on its SL (sports, light) program when, at a Daimler-Benz Board meeting in June 1951, the decision was made to re-enter motor racing at Formula 1 and sports racing levels. For its
This review of some of the more significant vehicles from this past year's motor shows showcases trends in design and technology from the world's automakers. Concepts highlighted here include some of the many vehicles introduced at acclaimed shows in Geneva, Seoul, Frankfurt, Tokyo, Detroit; and Chicago. One major trend from most of the venues was the distinct movement away from pure automobiles, many of the vehicles being station wagons, minivans, SUVs, or tall minicars or hybrids of one or more. When the first Seoul show was held back in 1995, Korea's personal transport was invariably sedan types. Now, the streets of Seoul, and elsewhere in the country, have more tall minis, minivans, and SUVs, with a sprinkle of sporty coupes. In Tokyo, there were plenty of concept vehicles-in fact more of them than ever before-and some significant new technologies, many in answer to the demands of an environmental and resource-conscious world. Another show car trend among the Japanese automakers
The purpose of this SAE Recommended Practice is to provide a common electrical and mechanical interface specification that can be used to design electronic accelerator pedal position sensors and electronic control systems for use in medium—and heavy-duty vehicle applications.
Items per page:
50
1 – 42 of 42