Browse Topic: Automatic transmissions

Items (1,412)

Comprehensive Durability Assessment of Planet Carrier in Heavy-Duty Tipper Gearboxes Using RLDA Torque Data

2026-26-0443

1/16/2026

In heavy-duty tippers, where challenging conditions demand high torque, planet carriers play a crucial role by enabling efficient load distribution and torque transmission while supporting gear ratio and speed variation in space-constrained systems such as automatic transmissions, hybrid drivetrains, and electric vehicles. This paper focuses on the comprehensive durability performance assessment of planet carrier housing (PCH) using duty cycles derived from road load data acquisition (RLDA) measurements for a heavy-duty tipper gearbox development program. The existing Design Validation Plan (DVP) for the planet carrier considers first gear utilization of 10-15% at 40% vehicle overload, in line with historical data. However, recent trends in mining applications revealed vehicle overloads of 55-65%, leading to an increase in first gear utilization (25-35%). This shift presents challenges for original equipment manufacturer (OEM) to enhance design durability while incorporating additional safety margins to meet the demands of a competitive, cost-driven market. To address this discrepancy, road load data was collected on a heavy-duty tipper with 65% abusive overloads. Torque telemetry on the propeller shaft captured RLDA data, which was processed to generate a torque profile for the planet carrier. This profile was then used to define the duty cycle via torque rainflow matrices across various gear conditions. The data revealed a 35% first gear utilization, prompting a revision of the existing DVP using this field-reflective data. Using revised DVP, a comprehensive durability assessment of the planet carrier was conducted, considering the torque rainflow matrices for all gear operating conditions. The fatigue assessment included the effect of induction hardening using a boundary layer approach in the commercial fatigue solver FEMFAT. Critical locations in the planet carrier were identified and addressed through suitable design modifications to meet the fatigue damage targets of the revised DVP. The final prototype design was validated through physical testing, showing no failures and aligning well with simulation predictions.

Bagane, Shivraj, Pendse, Ameya

Gear Ratio Variation Concept Influence on Energy Efficiency Optimization of Light Vehicles

2025-36-0104

12/18/2025

The growing concern regarding global warming pushes the contribution of all emitting sources to mitigate greenhouse gases. The significant light passenger vehicle fleet deserves continued attention, both in the implementation of more efficient new technologies and in the optimization of conventional technologies, which are still widely used. The vehicle’s energy efficiency is directly influenced by the coupling of the internal combustion engine to the transmission system. Engines have a restricted operation region of maximum efficiency that must be adequately explored by the transmission system in the different conditions of vehicle use. Thus, this paper analyzes and quantifies the sensitivity of the vehicle’s energy efficiency of two distinct engine technologies, naturally aspirated and turbocharged, coupled to an automatic transmission system with six discrete or continuously variable gears. Experimental data on the overall efficiency of the engines and the transmission concepts, discrete or continuously variable, are used in a 1D mathematical model of a vehicle, developed to numerically simulate the fuel consumption of the four possible engine and transmission configurations as a function of the vehicle category and driving cycles. Initial results indicate an advantage of around 2% in continuously varying the transmission ratio when compared to the configuration with discrete gears, which represents a significant gain in fuel consumption.

Rovai, Fernando Fusco, Menezes Lourenço, Maria Augusta de, Rohrig, Marcelo

Automatic Transmissions - Schematic Diagrams

J647_202512 (Current)

12/1/2025

The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied) and in gear. For illustrative purposes, some typical transmissions are shown.

Automatic Transmission and Transaxle Committee

Development of Electronic Control in Strong Hybrid Motorcycle

2025-32-0091

11/3/2025

In response to the growing demand for environmental performance, the mobility industry is actively developing electrification, and in particular, the use of Battery Electric Vehicles (BEV) in commuting motorcycles is advancing. However, in the case of vehicles for leisure, which require high riding performance, there are problems such as cruising range and charging time, and there are currently few mass-produced models. Therefore, we proposed a Hybrid Electric Vehicle (HEV) type Motorcycle (MC) to achieve both environmental performance and high riding performance by means other than BEV. The proposed vehicle is equipped with a strong type hybrid system in which an engine and a drive motor are connected in parallel via a hydraulic electronically controlled clutch. It is possible to drive only by motor (EV driving) or by hybrid driving powered by both the engine and the motor (HEV driving). In order to improve environmental performance, it is necessary to develop a function for switching between EV and HEV driving and an automatic transmission function. In motorcycles, which are lighter than passenger cars, it has been an important issue to achieve the required functions without causing discomfort to the rider. In order to solve this problem, we worked on torque distribution control between the engine and motor according to the rider operation and the remaining battery capacity and developed coordinated control of the electronically controlled hydraulic clutch and electronically controlled transmission unit. We achieved low fuel consumption comparable to that of the 250cc class while maintaining the riding feeling. This paper describes the configuration of the strong hybrid system to achieve both environmental performance and high riding performance, and then discusses the electronic control technology, the technical issues, and the solutions.

Obayashi, Kosuke, Terai, Shohei, Jino, Kenichi, Kawai, Daisuke

Revolutionizing Two-Wheeler Gear Shifting: A Cost-Effective Approach for Clutch-Less Gear Shift

2025-32-0088

11/3/2025

Automotive manufacturers are constantly striving to enhance the performance and comfort of vehicles, particularly in terms of acceleration and driving experience which is a perceived behavior. The gear shift procedure plays a significant role in this aspect. Frequent actuation of clutch and throttle for gear shift in a manual gear shift transmission is one of the causes for human fatigue while driving, especially in 2-wheelers. The speed reduction during gear shift also leads to lower acceleration timing. With advancements in technology and a growing emphasis on comfortable driving experiences, clutch-less gear shift in a geared vehicle is one of the most sought-after features. Automatic transmissions are often expensive and increases system complexity, making them less accessible in particular for 2-wheeler market. Therefore, there is a need for developing a cost-effective and affordable solution to address this problem statement. The current work presents a simplified software-based solution that allows riders to shift gears effortlessly, without the need of clutch or throttle modulations. This not only reduces the amount of effort and fatigue experienced by the rider, but also improves acceleration timings. The difference in vehicle’s drivability as compared to system with dedicated shift assist sensor is not perceived by a general rider. The system utilizes existing sensors such as engine speed, vehicle speed, throttle or accelerator pedal, gear position, and clutch position sensors. Based on the signals received from these sensors, the engine management system detects the rider’s intent to shift gears without throttle or clutch actuation, modifies the engine torque, and allows for smooth gear shift when the gear lever is pressed. The torque change is realized through a change in ignition, air, fuel, or any combination of them. Since no additional hardware is required, this cost-effective feature can be implemented in a wide range of two-wheelers from cost sensitive commuter vehicles to high-performance applications.

Jois, Dinkar

Aluminum Alloy Castings, High Strength, 4.5Cu - 0.70Ag - 0.30Mn - 0.25Mg - 0.25Ti (A201.0-T7), Solution Heat Treated and Overaged

AMS4229H (Current)

9/10/2025

This specification covers an aluminum alloy in the form of sand, permanent mold, and composite mold castings with nominal wall thickness up to 1.0 inch (25 mm) or nominal weight up to 50 pounds (23 kg) (see 8.2 and 8.8).

AMS D Nonferrous Alloys Committee

SAE No. 2 Friction Test Machine µPVT Test

J2490_202509 (Current)

9/10/2025

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a µPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction material b Fluid c Reaction plates These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document. This procedure is intended to evaluate the midpoint, endpoint, and breakaway coefficients and endpoint/midpoint ratios. The procedure can be used to demonstrate changes that occur between the different levels of engagement speed, sump temperature, and apply pressure. Refer to SAE J2487, SAE J2488, or SAE J2489 for coefficient variations due to changes in power level. The procedure, as described in detail in Table 1, consists of four 50 cycle break-in levels at 3500 rpm with increasing steps of apply pressure, followed by 16 levels consisting of 25 dynamic engagements, and one breakaway following completion of the 25th dynamic cycle. The 16 levels are achieved by varying initial engagement speed, apply pressure, and oil sump temperature while the inertia is kept constant at 0.701 kg/m2.

Automatic Transmission and Transaxle Committee

Hydrodynamic Drives Terminology

J641_202508 (Current)

8/22/2025

Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, SAE appointed a committee to standardize terminology, test procedures, data recording, design symbols, and so forth in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.

Automatic Transmission and Transaxle Committee

SAE No. 2 Friction Test Machine 3600 rpm Stepped Power Test

J2487_202507 (Current)

7/16/2025

This SAE Recommended Practice is intended as the definition of a standard test, but it may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 3600 rpm stepped power test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 3600 rpm and is intended as a standard procedure for common use by both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction material b Fluid c Reaction plates These three variables must be clearly identified when reporting the results of using this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document. This procedure is not intended to evaluate the initial coefficient or break-in characteristics. For this information, refer to SAE J2490.

Automatic Transmission and Transaxle Committee

Research on Shift Sound Quality Control Strategy for Active Sound Generation System in Automobile

2025-01-0019

5/5/2025

The active sound synthesis system of electric vehicles plays an important role in improving the sound perception and transmission of working condition information inside the vehicle. Nowadays, the active sound synthesis system inside the vehicle has become standard equipment in electric vehicles of major electric vehicle manufacturers to meet the user groups' demand for driving and riding experience. In order to enrich the driving experience of electric vehicles and automatic transmission vehicles, the sound performance should be close to the immersiveness and dynamic feedback brought by traditional manual transmission fuel vehicles. Based on the active sound synthesis algorithm in the car, this paper proposes an adaptive shift sound quality control strategy suitable for complex and changeable working conditions, with the aim of simulating the real shift sound of the engine. First, the motor speed offset is accurately calculated based on the transmission ratio of each gear of the gearbox, and then fitted with the real-time motor speed to generate a highly simulated virtual speed for the sound synthesis algorithm. Secondly, linear interpolation is used to optimize the speed connection between complex and variable working conditions to ensure smooth transition of sound waves between multiple working conditions; Then, in order to improve the accuracy of system response, a constant compensation factor is introduced so that the virtual speed can sensitively follow the fluctuation of the actual motor speed, thereby achieving constant consistency of the gear shifting sound effect; Finally, the CAN signal of the actual vehicle driving condition is used as input to synthesize the shifting sound based on simulation. The conclusion shows that the shifting sound quality control strategy is suitable for multiple working conditions of electric vehicles, and can accurately and effectively simulate the acceleration sound of fuel vehicles with shifting, thus improving user experience and comfort.

Zhou, Xilong, Liu, Zhien, Xie, Liping, Yu, Shangbo, Lu, Chihua, Gao, Xiang, Yongsheng, Wang

Trends in the Automated and AutomaticTransmission Systems for Two Wheeled Vehicles

2024-32-0061

4/18/2025

The two-wheeler industry features a diverse range of transmission systems catering to varied riding preferences and market demands. Manual transmissions offer direct gear control, favored by enthusiasts for its precision and customizable performance. Automatic transmissions simplify riding, especially in urban settings, eliminating manual gear shifts and reducing rider fatigue. Understanding the dynamics of transmission systems in the two-wheeler space is crucial for manufacturers, engineers, policymakers, and riders alike. It informs product development, regulatory compliance efforts, and market positioning initiatives in an increasingly competitive and innovation-driven industry landscape. DCT (Dual Clutch Transmission) and manual transmissions represent extremes in rider engagement, automation, and cost. While DCT offers seamless gear changes and convenience at a higher price point, manual transmissions provide direct control and a tactile experience with lower initial costs. Riders weigh these factors when choosing between technological innovation and traditional engagement. Between these two extremes, certain transmissions systems provide manual gear selection with automatic clutch operation, appealing to riders seeking control without the complexities of manual clutch manipulation like the E-Clutch. Continuously Variable Transmission (CVT) systems represent a notable innovation, offering seamless gear ratio adjustments and optimized engine output across riding conditions, enhancing ride quality and rider comfort, particularly in urban environments and have gained a lot of traction in the past decade. Each transmission system presents distinct advantages and challenges, influencing rider preferences and manufacturer strategies. Understanding the dynamics of transmission systems in the two-wheeler space is crucial for manufacturers, engineers, policymakers, and riders alike. It informs product development, regulatory compliance efforts, and market positioning initiatives in an increasingly competitive and innovation-driven industry landscape. The introduction of Semi-Automated Manual Transmission (SMT) stands as a bridge, blending the precision of automated gear shifts with the visceral engagement of manual control. SMT enables clutch less gear shifts, providing riders with a unique synthesis of technological innovation and the hands-on experience enthusiasts cherish. Beyond preserving the art of manual transmission, SMT addresses challenges associated with manual gear changes, mitigating issues like gear grinding and missed shifts. Positioned at the intersection of automated efficiency and the enduring appeal of manual engagement, SMT represents a blend of conventional mechanics and modern-day power electronics.

Kundu, Prantik

Study on an Urban Ramp Driving Cycle Using Self-Organizing Map Neural Network

2025-01-8259

4/1/2025

To tackle the issue of lacking slope information in urban driving cycles used for vehicle performance evaluation, a construction method for urban ramp driving cycle (URDC) is formulated based on self-organizing map (SOM) neural network. The fundamental data regarding vehicles driving on typical roads with urban ramp characteristics and road slopes were collected using the method of average traffic flow, which were then pre-processed and divided into short-range segments; and twenty parameters that can represent the operation characteristics of vehicle driving on urban ramp were selected as the feature parameters of short-range segments. Dimension of the selected feature parameters was then reduced by means of principal component analysis. And a SOM neural network was applied in cluster analysis to classify the short-range segments. An URDC with velocity and slope information were constructed by combination of short-range segments with highly relevant coefficients according to the principle of smooth connection of slope. The constructed URDC was applied in the urban ramp driving performance test of automatic transmission via simulation, which shows that the constructed driving cycle can reflect the driving characteristics of vehicles driving on urban ramps, which can be used as the benchmark driving cycle for performance test of vehicle driving on urban ramp.

Yin, Xiaofeng, Wu, Zhimin, Liang, Yiming, Wang, Peng, Xie, Yu

WITHDRAWAL NOTICE

2025-01-8506.01

4/1/2025

Research on the Change of Mind Control during Gearshift in Hybrid System

2025-01-8509

4/1/2025

This paper initially delineates the control process of driver-initiated gear changes. The gear-shifting point control module computes the new target gear based on the current updated driving state, and the gear-shifting point decision module assesses the rationality of the new target gear and conveys it to the gear-shifting timing control module. The gear-shifting timing control module selects the reasonable new stage in accordance with the current execution status and outputs the new target gear, coordinating the clutch control module and the brake control module to regulate the clutch engagement/disengagement and the switches of the two clutches. Altering the intention regarding gear changes encompasses gear replacement and variations in power type, which involve the necessary recalculation of the target speed based on the new target gear. Secondly, the conditions for the “change of mind” request in the speed stage are stipulated, which is the stage where the input shaft speed is synchronized with the combined side clutch speed, and the energy condition must be fulfilled to prevent the clutch from overheating, including the calculation of the available energy of the clutch. The executable “change of mind” request. The proposed scheme eliminates the need for the clutch temperature sensor to participate in the control process, and the “change of mind” process can be accomplished by saving multiple clutch temperature sensors for the multi-clutch system. It plays a significant role in enhancing driving performance and clutch temperature control.

Jing, Junchao, Huang, Weishan, Li, Dongfei, Zuo, Botao, Liu, Yiqiang

HEV Fuel Consumption Analysis, Including Transmission Losses

2025-01-8535

4/1/2025

A first-order HEV fuel consumption model is developed by solving for the transition between electric drive at low and negative traction power and engine drive and charging at high traction power. Turning the engine on above the ‘breakeven power’ minimizes fuel consumption: indirect electric driving from engine charging is more efficient below it, and direct engine operation above it. This is derived analytically and observed in benchmarking data on different drive cycles. The engine breakeven bmep is a function of engine loss and electric round trip efficiency. The location of the breakeven power on the cumulative traction work vs. time distribution enables the estimation of the engine running time at high traction power levels and of the engine work needed for extended electric driving. The approach is generalized to HEVs with substantial transmission and driveline (T&D) losses, such as the ‘P2’ Rear Wheel Drive (RWD) hybrid vehicles, with a motor sandwiched between the engine and the automatic transmission. The T&D losses increase the total work required from the engine and cause longer engine running times. The analytic modeling is enabled by the major sub-systems - engine, motor, transmission, and axle - having linear transfer functions. The HEV model extends that for ICEV and BEV, adding all the indicated loads on the power source - internal, traction, accessories – over a cycle and dividing by the combined system marginal efficiency. Examples show that it describes the energy consumption of a range of powertrain systems in different vehicles and operating cycles.

Phlips, Patrick

Coordinated Clutch Slip Control for The Engine Start with Power-On Downshift in a P2 Hybrid Automatic Transmission

2025-01-7026

1/31/2025

The impact and vibration problem during gear shifting and mode switching of the P2 hybrid 8AT system of new energy vehicles seriously affects driving comfort. This paper proposed a collaborative clutch slip and friction control strategy for a P2 hybrid power system with power downshifting and engine starting to reduce transient shock vibration during the power system operation. A dynamic model of the P2 hybrid system was established, including a physical model of the engine, motor, clutch, 8AT transmission mechanism, and driving resistance. The transient dynamic behavior of the P2 hybrid system with power downshifting and engine starting was systematically studied. On this basis, with the goal of consistent power response and smooth gear shifting, a multi-stage collaborative control strategy including the motor, engine, and clutch under the power downshifting condition was formulated. Model-in-loop simulation verification was carried out based on MATLAB/Simulink platform. The simulation results show that compared with traditional methods, the proposed control method can effectively improve the power performance and comfort of the P2 hybrid power system.

Song, Tingbin, Wang, Shuhan, Xu, Xiangyang, Qiu, Longhui

Rectangular Cross Section Polymeric Sealing Rings

J2310_202412 (Current)

12/6/2024

The purpose of this SAE Recommended Practice is to establish guidelines for the automatic transmission and hydraulic systems engineer to design rectangular cross section seals for rotating and static grooved shaft applications. Also included are property comparisons of polymeric materials suitable for these applications. Historically, material covered in this document is not intended to include aluminum contact applications.

Automatic Transmission and Transaxle Committee

One-Way Clutches - Nomenclature and Terminology

J1087_202408 (Current)

8/12/2024

The definitions and illustrations in this SAE Recommended Practice are intended to establish common nomenclature and terminology for automotive transmission one-way clutches.

Automatic Transmission and Transaxle Committee

Modeling and Time Discrete Characteristics Analysis of the Oil Filling Process of Wet Clutch for a Specialized Vehicle’s Automatic Transmission

2024-01-2284

4/9/2024

The automatic transmission of a specialized vehicle encountered challenges in achieving stable oil filling time due to the considerable variability of related parameters and the non-linear trends in the variation of individual product parameters over time. To investigate the underlying causes of this phenomenon and enhance the oil filling efficiency, a detailed model of the clutch oil filling process during gear shifting was established in this paper, which included dynamic models of the key components such as the hydraulic system, clutch, proportional valve, and oil passages. Physical experiments were performed on the test bench to compare with the simulation results. The results showed that the correlation between the simulation model and the test bench was well, which verified the effectiveness of the simulation model. Based on analyzing the clutch filling process, the effects of parameters such as orifice diameter, piston cavity clearance, clutch gap, and oil injection pressure on the filling time response of the system were primarily considered, and dynamic simulations were carried out to investigate the influence of these parameters on the clutch filling time. These results provided substantial theoretical support for the optimization and calibration of relevant parameters in the subsequent design iterations of the specialized vehicle's automatic transmission.

Guo, Jun, Feng, Guangjun, Wu, Jinglai, Zhang, Yunqing

The New Toyota 2.4L L4 Turbo Engine with 8AT and 1-Motor Hybrid Electric Powertrains for Midsize Pickup Trucks

2024-01-2089

4/9/2024

Toyota has developed a new 2.4L L4 turbo (2.4L-T) engine with 8AT and 1-motor hybrid electric powertrains for midsize pickup trucks. The aim of these powertrains is to fulfill both strict fuel economy and emission regulations toward “Carbon Neutrality”, while exceeding customer expectations. The new 2.4L L4 turbocharged gasoline engine complies with severe Tier3 Bin30/LEVIII SULEV30 emission regulations for body-on-frame midsize pickup trucks improving both thermal efficiency and maximum torque. This engine is matched with a newly developed 8-speed automatic transmission with wide range and close step gear ratios and extended lock-up range to fulfill three trade-off performances: powerful driving, NVH and fuel economy. In addition, a 1-motor hybrid electric version is developed with a motor generator and disconnect clutch between the engine and transmission. This hybrid architecture provides EV driving, which enhances the NVH and fuel economy, and provides additional acceleration with motor assist. Moreover, this hybrid electric system can meet customers’ “overlanding” electric power usage expectations. These performances will help exceed customer expectations for various pickup truck uses such as on-road, off-road and towing situations.

Endo, Motoshiro, Bridge, Alistair, Ikeda, Akihiro, Miyamoto, Koichi, Miyazaki, Terufumi, Hosoda, Fuminori, Herring, Craig, Wallace, James J., Hu, Mu

Vehicle Control Development - Converting a Medium-Duty Commercial Truck into a Battery Electric Vehicle

2024-01-2047

4/9/2024

The transition towards electrification in commercial vehicles has received more attention in recent years. This paper details the conversion of a production Medium-Duty class-5 commercial truck, originally equipped with a gasoline engine and 10-speed automatic transmission, into a battery electric vehicle (BEV). The conversion process involved the removal of the internal combustion engine, transmission, and differential unit, followed by the integration of an ePropulsion system, including a newly developed dual-motor beam axle that propels the rear wheels. Other systems added include an 800V/99 kWh battery pack, advanced silicon carbide (SiC) inverters, an upgraded thermal management system, and a DC fast charging system. A key part of the work was the development of the propulsion system controls, which prioritized drivability, NVH suppression, and energy optimization. The improvement of the electrified truck compared to the gasoline version in responsiveness and reduced noise emissions underscores the efficacy of the BEV's design. This enhanced performance was substantiated by a quantifiable reduction in brake use, resulting in improved energy efficiency. This paper describes the development, implementation, and verification of the vehicle control systems, including the interface with the existing production vehicle controllers, the inverter control strategy, a one-pedal driving function, the management of the DC fast charging protocols, a thermal management system, fault diagnosis algorithms, and an intuitive in-vehicle display interface. Performance evaluations have demonstrated a remarkable 40%+ improvement in the BEV's 0-100 km/h acceleration compared to the gasoline-powered stock vehicle. The paper also addresses some obstacles encountered during the electrification process.

Liu, Xiaobing, Guo, Chengyun, Rama, Neeraj, Theunissen, Frans, Olin, Pete, Ling, Gang, Pan, Yang, Mohon, Sara, Van Maanen, Keith, Chen, Wei

2025 Kia Carnival MPV Hybrid brings unplugged PHEV power

24AUTP04_12

4/1/2024

The 2025 Kia Carnival MPV is acquiring a hybrid powertrain as part of the minivan's model year update that debuted at the Chicago Auto Show. The internal-combustion engine option remains the 3.5-L V6 GDI seen in the current Carnival and produces 287 hp and 260 lb-ft (353 Nm) that powers the front wheels through an 8-speed automatic transmission. Engine power is down slightly from the output of the V6 in the 2024 model (290 hp and 262 lb-ft [355 Nm]). It's the addition of an electric motor to the new hybrid model where things get interesting. The hybrid Carnival uses a 1.6-L turbocharged 4-cyl. and a 54 kW motor that produce a combined 242 hp and 271 lb-ft (367 Nm). The Carnival Hybrid MPV uses a 6-speed automatic transmission. Improved fuel economy is one reason for the new hybrid option. While Kia doesn't yet have official EPA estimates, a spokesperson told SAE Media that the target is 32 mpg combined. The current ICE-only Carnival gets 22 mpg.

Blanco, Sebastian

Fluid for Passenger Car Type Automatic Transmissions

J311_202402 (Current)

2/16/2024

This SAE Information Report details some of the equipment and procedures used to measure critical characteristics of automatic transmission fluid (ATF) used in current automatic transmissions. It is intended to assist those concerned with the design of transmission components, and with the selection and marketing of ATFs for the use in passenger car and light-duty truck automatic transmissions. The information contained herein will be helpful in understanding the terms related to properties, designations, and service applications of ATFs.

Fuels and Lubricants TC 3 Driveline and Chassis Lubrication

An Optimum Solution to Meet the Thermal Load Challenge in a High Mobility Military Vehicle

2024-26-0246

1/16/2024

Military vehicles are intended to operate at rugged terrains in adverse environmental conditions. Unlike a regular truck, these vehicles are powered by a much bigger engine and transmission to meet the vehicle performance parameters. Thermal systems in these vehicles are challenging. With the adverse climatic condition and driving terrains, the criticality of Engine cooling system is intensified. In this paper, a Cooling system is finalized for a high mobility military vehicle with higher power engine, Automatic transmission and a hydraulic retarder. Thermal load cases are different for each. Modelling is done in thermal simulation software KULI. A steady state simulation is done for engine and automatic transmission where-as transient simulation is performed for retarder. The aim is to finalize a cooling system circuit consisting of radiator, oil to air cooler and oil to water cooler which are interconnected to meet the heat load demand of engine, transmission and retarder together.

AT, Shajahan, Kiran, Nalavadath, Rao, Bonthala

Development of Transmission Adaptor for Diesel Engine Application

2024-26-0336

1/16/2024

Transmission adapter is solid, located on cylinder block, on which sits the transmission housing. The function of a flexplate is to provide a mounting point for a torque converter which is used to couple the engine and transmission together when an automatic transmission is used. Transmission adapter provide access for torque convertor and flexplate assembly and protect the flexplate from external environment. Transmission adapter is also support and locate the starter. This study deals with different alloy grade material use, improvement in process to reduce porosity. Porosity observed in first samples of the proposed grade material. The study represents investigation of Transmission adaptor porosity root cause. This also included visual observation, radiography -X ray testing, analysis, 3D scans, dimensional inspection, chemical analysis and comparison, tensile testing, truck testing validation tasks. Make sure critical parameter of the clearance meet between flexplate and transmission adapter. Result of the material alloy change is passed and field validation on truck application ran more than 150,000 miles without any issue.

Karale, Pranjali

Dynamic Automatic Transmission Oil Life Prediction Using Machine Learning

2024-26-0036

1/16/2024

Automatic transmission fluid (ATF) or automatic transmission oil which has high potential resource conservation capability considering the current servicing methods. It also plays a crucial role in the performance and longevity of the transmission system. Predicting the actual life of the ATF can be challenging due to various factors such as its application, driving conditions, driving behavior, oil grade, and maintenance schedules, which can help prevent costly repairs and improve the vehicle’s overall performance. Present work is focused on developing a predictive model utilizing the critical oil properties in real time by giving an indication to the driver/fleet owner. Data is gathered by considering various vehicle parameters, including usage patterns such as shift density, vehicle load, torque, current gear, lock-up state, input/output shaft speed, oil temperature, and more. This data is obtained from a test vehicle over a specific period. The approach encompasses several steps, including data preprocessing, feature selection, model selection, model training, and evaluating the model. ML model is trained by using the data obtained from the test vehicle which classifies the oil quality and predicts the remaining mileage of the vehicle. The prediction can be done at any given time and is independent of the vehicle’s operating conditions. This model was deployed for live computations (classification - ok/not ok and remainder mileage) to simulate real-time monitoring of the end user. The future work will focus on real-time testing of an automatic transmission using ML approaches to predict transmission fluid’s life coupled with dynamic scenarios and potential fluid failure modes for informed decisions about ATF replacement schedules and maintenance.

Badiger, Aishwaryalaxmi, Priyadarshi, Priyamvad, Bhat, Goutam

Low-Speed Continuous Slip SAE No. 2 μPVT Procedure

J2964_202311 (Current)

11/15/2023

Automatic Transmission and Transaxle Committee

Planetary Gears - Terminology

J646_202310 (Current)

11/1/2023

Figures 1 through 6 illustrate in simplified form some of the more common planetary gears, gearsets, and geartrain arrangements in order to establish applicable terminology. Figures 7 and 8 provide additional examples that use elements of those gear arrangements.

Automatic Transmission and Transaxle Committee

2024 Toyota Land Cruiser returning to its roots

23AUTP09_13

9/1/2023

After three years away from the U.S. market with its range-topping SUV, the Land Cruiser, Toyota unveiled the redesigned 2024 Land Cruiser in Salt Lake City on Aug. 1. The model, long known around the world for its durability and offroad credentials, arrives with the SUV competition hotter than ever. The company said the new model will start at around $55,000. The new Land Cruiser has just one engine option, the i-Force Max turbo 2.4-L four-cylinder hybrid that generates 326 hp and 465 lb-ft (630 Nm) that is routed through an 8-speed automatic transmission. All models are equipped with what Toyota classifies as a “full-time four-wheel-drive system” with a lockable center differential and an electronically controlled 2-speed transfer case to impart high- and low-range capability. Also standard is a lockable rear differential to apportion power in a 50/50 ratio across the rear axle.

Clonts, Chris

Automatic Transmission Functions—Terminology

J649_202309 (Current)

9/1/2023

The following is a list of the most common terminology used in describing automatic transmission functions.

Automatic Transmission and Transaxle Committee

Hydrodynamic Drive Test Code

J643_202308 (Current)

8/1/2023

The range of test conditions on the dynamometer shall be sufficient to determine the primary operating characteristics corresponding to the full range of vehicle operations. The characteristics to be determined are: a Torque ratio versus speed ratio and output speed b Input speed versus speed ratio and output speed c Efficiency versus speed ratio and output speed d Capacity factor versus speed ratio and output speed e Input torque versus input speed NOTE: For more information about these characteristics and the design of hydrodynamic drives, refer to “Design Practices: Passenger Car Automatic Transmissions,” SAE Advances in Engineering, AE-18 (Third Ed.) or AE-29 (Fourth Ed.).

Automatic Transmission and Transaxle Committee

Fuel Economy Measurement Road Test Procedure

J1082_202305 (Current)

5/10/2023

This SAE Standard incorporates driving cycles that produce fuel consumption data relating to Urban, Suburban, and Interstate driving patterns and is intended to be used to determine the relative fuel economy among vehicles and driving patterns under warmed-up conditions on test tracks, suitable roads, or chassis dynamometers.1

Light Duty Vehicle Performance and Economy Measure Committee

Reducing Fuel Consumption on a Heavy-Duty Nonroad Vehicle: Conventional Powertrain Modifications

2023-01-0466

4/11/2023

This investigation focuses on conventional powertrain technologies that provide operational synergy based on customer utilization to reduce fuel consumption for a heavy-duty, nonroad (off-road) material handler. The vehicle of interest is a Pettibone Cary-Lift 204i, with a base weight of 50,000 lbs. and a lift capacity of 20,000 lbs. The conventional powertrain consists of a US Tier 4 Final diesel engine, a non-lockup torque converter, a four-speed powershift automatic transmission, and all-wheel drive. The paper will present a base vehicle energy/fuel consumption breakdown of propulsion, hydraulic and idle distribution based on a representative end-user drive cycle. The baseline vehicle test data was then used to develop a correlated lumped parameter model of the vehicle-powertrain-hydraulic system that can be used to explore technology integration that can reduce fuel consumption. Two conventional powertrain modifications are explored that provide potential pathways that significantly alter the base powertrain and include 1.) a torque converter disconnect clutch and 2.) a low voltage stop-start system that have the potential to reduce fuel consumption on the end user representative drive cycle by 10.3% and 9.8%, respectively. Details of how the powertrain modifications would be executed, physical hardware, and application to other heavy-duty nonroad vehicle applications are included in the discussion.

Goodenough, Bryant, Czarnecki, Alexander, Robinette, Darrell, Worm, Jeremy, Latendresse, Phil, Westman, John

Transmission Shifting Analysis and Model Validation for Medium Duty Vehicles

2023-01-0196

4/11/2023

Over the past couple of years, Argonne National Laboratory has tested, analyzed, and validated automobile models for the light duty vehicle class, including several types of powertrains including conventional, hybrid electric, plug-in hybrid electric and battery electric vehicles. Argonne’s previous works focused on the light duty vehicle models, but no work has been done on medium and heavy-duty vehicles. This study focuses on the validation of shifting control in advanced automatic transmission technologies for medium duty vehicles by using Argonne’s model-based high-fidelity, forward-looking, vehicle simulation tool, Autonomie. Different medium duty vehicles, from Argonne’s own fleet, including the Ram 2500, Ford F-250 and Ford F-350, were tested with the equipment for OBD (on-board diagnostics) signal data record. For the medium duty vehicles, a workflow process was used to import test data. In addition to importing measured test signals into the Autonomie environment, the process also calculated some of the critical missing signals, such as each component effort or flow signal. Numerous analysis functions have been developed to quickly analyze the shifting map, using the integrated test data in Autonomie to generate model parameters. In addition, a set of calibrations for the generic shifting algorithm was developed to match the test data. Finally, we demonstrated the validation of Autonomie transmission component models and shifting control strategy by using medium duty vehicle test data over different driving records.

Kim, Namdoo, Islam, Ehsan Sabri, Vijayagopal, Ram, Pamminger, Michael

Development of Control System for Parallel Hybrid System with Turbo Engine

2023-01-0547

4/11/2023

This paper describes a new control technology that coordinates the operation of multiple actuators in a new hybrid electric vehicle (HEV) system consisting of a turbocharged engine, front and rear electric motors, two clutches, and a 6-speed automatic transmission. The development concept for this control technology is to achieve the driver’s desired acceleration G with a natural feeling engine speed. First, to realize linear acceleration G even while the engine is starting from EV mode, clutch hydraulic pressure reduction control is implemented. Furthermore, the engine start timing is optimized to prevent delayed drive force response by predicting the required maximum power during cranking. Second, to realize linear acceleration, this control selects the proper gear position based on the available battery power, considering noise and vibration (NV) restrictions and turbocharging response delays. Finally, to precisely control engine speed when the clutch is not directly connected, feedforward (F/F) controller and feedback (F/B) controller are implemented. The F/B controller for the engine was specially designed for response and stability considering the dead-time of engine torque response and disturbances. When disturbances occur, this controller reduces both the overshoot and settling time to the target value as compared to using a simple PI controller. These control technologies achieve shorter engine start time by 20%, powerful acceleration at low engine speed, and precise engine speed control. These contribute to driving pleasure of the new parallel hybrid system.

Takeichi, Akira, Kosaka, Koshiro, NOBE, Daigo, Suzuki, Toshiaki, Miyake, Shota, Tsukamoto, Norihiro

Development of e-AWD Hybrid System with Turbo Engine for SUVs

2023-01-0470

4/11/2023

This paper describes the development of a new e-AWD hybrid system developed for SUVs. This hybrid system consists of a high-torque 2.4-liter turbocharged engine and a front unit that contains a 6-speed automatic transmission, an electric motor, and an inverter. It also includes a rear eAxle unit that contains a water-cooled high-power motor, an inverter, and a reduction gear, as well as a bipolar nickel-metal hydride battery. By combining a turbo engine that can output high torque across a wide range of engine rpm with two electric motors (front and rear), this system achieves both smooth acceleration with a torquey driving feeling and rapid response when the accelerator pedal is pressed. In addition, new AWD control using the water-cooled rear motor realized more stable cornering performance than the previous e-AWD system. By developing a hybrid system with appealing new driving characteristics, it was possible to increase the variety of electric powertrains available to customers as part of measures to help achieve carbon neutrality.

Sasaki, Koichi, Kamichi, Kensuke, Ishimoto, Manabu, Kojima, Sei, Bridge, Alistair, Takebayashi, Noritaka

Engine Idle Creep Testing and Modeling of Vehicles Equipped with CVT, DCT, and Conventional Automatic Transmissions

2023-01-0620

4/11/2023

Determining impact speeds is an important factor in any accident reconstruction. Event data recorders are now commonplace in on-road vehicles and provide an added tool for the accident reconstructionist. However, in low-speed collisions where impact severity is often important, event data recorders fail to record data as the minimum threshold for impact severity sometimes is not met. Alternatively, damage-based methods may be ineffective in quantifying the severity of the impact due to a lack of defined vehicle crush damage. These types of scenarios oftentimes present themselves as a bullet vehicle in the beginning processes of accelerating from a stop or when a stopped target vehicle is rear-ended from behind by the bullet vehicle. A specific subset of this scenario might entail the foot of the driver of the bullet vehicle coming off the brake pedal, allowing the bullet vehicle to “creep” forward at engine idle speeds and impacting the target vehicle resulting in no visible crush damage to either vehicle. Eighteen vehicles with conventional automatic transmissions were tested, which included sedans, sport utility vehicles (SUVs), pickup trucks, and vans. Two vehicles (one sedan, one wagon) equipped with dual-clutch transmissions (DCTs) and three vehicles (one sedan, one hatchback, and one wagon) equipped with continuously variable transmissions (CVTs) were also tested. These vehicles were allowed to accelerate at idle with the brake pedals released. Acceleration, speed, distance, and engine speed data were collected for multiple vehicles runs in both forward and reverse directions over level ground. The data resulting from this study were then compared/contrasted among the different drivetrains and also previously published literature to determine similarities and differences. Previous study data sets were also incorporated with the authors’ data to improve predicted vehicle speed.

Timbario, Thomas A., Stoner, Jacob, Sheldon II, Stuart

The influence of gear step selection on a passenger car fuel consumption

2022-36-0046

2/10/2023

Several factors interfere with vehicle fuel consumption. Among them, the relationship between the transmission and the engine, defined as matching, stands out. This paper seeks to analyze the impact of varying the gear step values and, consequently, the intermediate gear ratios on a passenger vehicle's fuel consumption. The vehicle chosen for this analysis was the 2018 Toyota Camry, which has a A25A-FKS "Dynamic Force" engine model with 2.5 liters and 4-cylinders, operating under an Atkinson cycle. The transmission chosen is the UB80E model, which is originally used in this vehicle. It consists of an automatic transmission with 8 gears, coupled to the engine by a Trilok converter. Performance data and brake specific fuel consumption values for this engine were obtained from researches carried out by the U.S. Environmental Protection Agency (EPA). For relating gear step selection influence on the vehicle fuel consumption considering two different driving scenarios, a mathematical model was developed using MATLAB software. In this model, the transmission ratios of the first and eighth gears are kept constant, varying only the intermediate gear's transmission ratio values. Using vehicle velocity and accelerations as model inputs, engine speed and torque are calculated to obtain specific brake fuel consumption values for each one of the intermediate gears. In possession of these values, through optimization, the transmissions that provided the lowest fuel consumption for each driving scenario are obtained. The chosen driving cycles are described in NBR 6601:2000 and NBR 7024:2001 standards and approach road and urban scenarios respectively.

Vianna Gama, Lucas, Alberto Souza, Rogério Felipe, De Macedo, Vinicius Ribeiro Cavaleiro, Rossi Lopes, Elias Dias, Simão Rodrigues, Gustavo

Better performance in fine-grain steel for transmission

2022-36-0033

2/10/2023

Manual transmissions for passenger cars are facing pressures due to rapid growth of automatic transmissions, which already represents more than 60% of Brazil market, and from higher torque demand due to strict emission legislation, which turbo engines had presented great contribution to it. To solve this contradictory issue, gears with higher strength and lower cost have been studied to replacement Nickel by Niobium in the steels. Furthermore, this technology could be applied to solve the issues with electrified vehicle, where high torque, speed and lifetime are demanded pursued for gears. This study aimed to build prototypes and compare the S-N curves, fracture analysis, microstructure for three kinds of steels (QS4321 with Ni, QS1916 FG without Ni & with Nb and QS 1916 without Ni and Nb) in the condition carburized, hardened and tempered with and without shot peening. The study showed technical feasibility in the replacement of Ni for Nb, therefore it should be continued for application in current production.

Nunes, Eduardo, Colosio, Marco, Galdino, Rafael, Freese, Samuel, Carlos Zambon, Antonio

Low-Speed Continuous Slip Durability Test

J3210_202211 (Current)

11/22/2022

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. This SAE No. 2 friction test monitors the µ-v curve for a negative slope which can be used to evaluate a wet clutch system (WCS) anti-shudder performance and can be used for any wet driveline mechanism. WCS shudder is considered a clutch failure condition. The cause of shudder is consistent with glazing as the primary failure mode. It has been shown that a substantial loss of the wet friction material surface porosity leads to a glaze forming on the friction material surface. This process typically leading to a negative dµ/dv slope over time as addressed in SAE 2020-01-0560. This procedure includes evaluation friction characteristics of wet clutch stystem (WCS) at various specific pressures, speeds, and temperatures, and an extended durability duty cycle test to evaluate the WCS during which the µ-v curve is monitored for a negative slope—a condition indicating the potential for shudder. This procedure can be used to compare the shudder potential of various WCS combinations of friction material and lubricant. It is recommended that testing be conducted on an SAE No. 2 or similar machine. Also use the same machine for all tests when comparing results. The amount of aging has not been correlated to vehicle mileage or vehicle shudder and should only be used as an example of a test that results in a severe negative slope on the µ-v test. This procedure is designed for a standard SAE plate clutch pack with one friction plate and two steel plates, but can be modified for any WCS configuration. This procedure is built on the basis of SAE J2964, with modified test parameters and test procedure to evaluate a WCS aging stability and predict anti-shudder performance. This procedure is intended as a recommended practice for both suppliers and end users. The only variables selected by the supplier or user of the friction system are: Friction plate with friction material (lining): Specify friction material, lot or batch number, groove pattern, and lining thickness. Fluid: Specify fluid and lot or batch number. Reaction (separator) plates: Use SAE standard as inticated below. Specify plates material, thickness, and lot or batch number. These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed—other than the friction material, test fluid, or reaction (separator) plates—the data may not be reported as being obtained using this document, but should be shown as a modified version of the procedure. The friction testing has a combination of modes, including short time continuous slip (C), ramp up and down speed sweeps (S), and static or breakaway slip (BA). The friction testing is done before break-in (BBI), after break-in (ABI), and after each aging test block (A). The general overview this test procedure is presented schematically in Figure 1. Reference the testing clutch geometric parameters are shown in Table 1. Various testing speeds, fluid temperatures, unit surface pressures, and slip timings are used during the different modes to simulate clutch operating conditions. The aging mode test parameters are selected to accelerate the WCS degradation response within the 120 hours total time. The obtained values of friction torque and resulting friction coefficient, friction coefficient slopes (gradients), fluid, and reaction plate temperatures allow comparison of the WCS wear resistance and resistance to aging. These parameters are utilized for evaluating the clutch anti-shudder performance. Details of the test modes operating conditions are presented in Section 5.

Automatic Transmission and Transaxle Committee

Automotive Transmission, Transaxle, and Electrified Transmission Terminology

J645_202211 (Current)

11/22/2022

The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.

Automatic Transmission and Transaxle Committee

Detection and Diagnosis of Speed Sensor Air Gap Change Fault

2022-01-705810/28/2022

Aiming at the fault that the speed signal of the automatic transmission output shaft Hall-type speed sensor fluctuates abnormally due to the change of the air gap, the method of fault detection and diagnosis is proposed. Firstly, a limited low-pass filter module was designed according to the characteristics of the fault, and a good filter effect is achieved. Secondly, by comparing the signals before and after filtering, a residual generator is designed, and an adaptive dynamic threshold is designed by analyzing the causes and influencing factors of the residual, which can configure a reliable and effective threshold for the generated residual in real time, which improves the fault identification robustness and effectiveness. Then, a fault debounce method is designed to avoid frequent false alarms of occasional faults. Finally, simulation verification proves the effectiveness of the method.

Wang, Shuhan, Zheng, Wei, Yao, Kun, Dong, Peng, Xu, Xiangyang, Dai, Zhenkun, Huang, Yajun, Zhang, Xiujuan, Liu, Yi, Wang, Kaifeng, Mao, Feihong

Application of Alternative Methodology to Select the Optimum Design of TCU Carrier Using FEA

2022-28-0357

10/5/2022

The transmission control unit is used in automobile domain, to control the automatic transmissions. TCU is associated with mechanical parts like Housing, Carrier, Hydraulic Plate etc. In this case, TCU carrier is mounted on hydraulic plate using a dowel pin to locate it accurately. During servicing of the TCU, Carrier with dowel pin is subjected to high displacement which leads to huge plastic deformation & failure of the carrier. A study was required using Finite Element Analysis for a series of designs to evaluate their structural stability and to recommend the best possible design. ANSYS tool is used for the simulation. During this study, when conventional method of reckoning stresses and strains as a criterion of comparison was adopted, it involved a tedious process & required many numbers of iterations. Despite plenty of iterations, it may not be possible to conclude the exact force at which the carrier fails or the max displacement it can withstand. The other reason to look for an alternative method is, the development team expectations about the structural stability of the carrier considering operating conditions is contradicting with the strains observed with conventional method. So, there was a need to develop alternative method to evaluate the carrier strength. Hence, stiffness criterion is obtained as a solution. Series of designs are compared based on stiffness & deformation criterion for loads ranging from operating load of 3 mm to maximum displacement load of 6 mm. The simulation results through this stiffness method obtained are also validated with testing results and accuracy of results is observed. This study using stiffness method helped us in selection of best possible carrier design suitable for maximum displacement load without any failure. Cost of testing for around 6 designs is reduced by using FEA and optimum design is also obtained.

Dama, Madhu, Aavula, Chandrika Yadav

Diagnostic Link Connector Security

J3138_202210 (Current)

10/4/2022

This document describes a set of recommended actions to take to increase the likelihood of safe vehicle operation when a device (external test equipment, data collection device, etc.) whose normal operation has been compromised by a source external to the vehicle is connected to the vehicle’s diagnostic system. The term “diagnostic system” is intended to be a generic way to reference all the different ways that diagnostic commands might be injected into the system. The guidance in this document is intended to improve security without significantly impacting the ability for franchised dealer or independent aftermarket external test tools to perform legitimate diagnosis and maintenance functions. The goal is that intrusive services are only allowed to be performed when the vehicle is in a Safe State such that even if the intrusive service were to be initiated with adversarial intent the consequences of such a service would still be acceptable.

Data Link Connector Vehicle Security Committee

Measurement of Material Properties for Wet Friction Materials

J2968/1_202209 (Current)

9/30/2022

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The specific purpose of this SAE Recommended Practice is to define a procedure to determine intrinsic properties of friction materials such as compressive modulus and rebound/recovery time at specific fatigue test pressures. Results from this test will both independently characterize the friction material and serve as input to the compression fatigue test. NOTE: If this test is intended to determine the rebound interval for the compression fatigue test, then the maximum test pressure (Pmax) in this procedure must be selected with future fatigue testing levels in mind. It is important that the rebound time is sufficient at the maximum apply pressure to allow the matieral to rebound back to its original thickness. Standard reporting processes are recommended. This procedure is intended for use by both suppliers and end users of wet friction materials. The only variables selected by the supplier or user of the friction system are: a Friction material. b Fluid. c Maximum load. d Fatigue test cycle requirements. These variables must be clearly identified when reporting the results of this test. Data shall not be reported as having been obtained using this procedure if any test parameters or system hardware described in this document are changed or deviated from in any way (other than the variables described above).

Automatic Transmission and Transaxle Committee

A Map-Driven Automatic Transmission for Selective Emissions Reduction in ICE Vehicles

2022-24-0026

9/16/2022

Automatic Transmissions managements are often based on throttle position and vehicle speed and mainly aim to reduce fuel consumption and carbon dioxide (CO2) emissions, in vehicles equipped with Internal Combustion Engines (ICE). This is an important goal from two viewpoints: fuel economy and greenhouse gases (GHG) containment, with benefits in terms of global warming and climate change. At the same time, traffic stops are due to the detection of other pollutants, as nitrogen oxides (NOx) and particulate matter (PMx), which are harmful for human health. This is particularly true in urban areas, especially during traffic jams. Moreover, localized high levels of the pollutants produced may not be detected by conventional and relatively far air quality detection stations. In this paper, a solution to efficiently detect air quality parameters near the vehicles is proposed, with the development of on-board low-cost monitoring air quality systems and a Vehicle to Vehicle (V2V) communication. Based on such data, an estimation of the pollutant to be contained is made and communicated to surrounding vehicles. Hence, their behaviors are modulated thanks to the Map-Driven Automatic Transmission (AT) Management, with a gear selection strategy that enforces the engine to operate in the lower part of a given map. From this viewpoint, a detailed Matlab/Simulink model of the vehicle was developed and validated against experimental data. Then, the AT strategy was tested in order to demonstrate its effectiveness, both on terms of fuel economy and GHG emissions or containment of a particular pollution, if required.

Scaffidi, Carlo Alessio, Tricomi, Giuseppe, Puliafito, Antonio, Distefano, Salvatore

Making the torque-transfer TRANSITION

22AUTP06_016/1/2022

Amsted Automotive Group saw the EV revolution coming and has ‘the means’ to deliver greater driveline efficiency. AAG's top engineers talk next-gen technology. A reckoning has arrived at suppliers whose product portfolios, engineering resources and R&D activities are not aligned with the EV horizon. The challenge of pivoting their focus to electrification, while sustaining the incumbent business, has been particularly vexing for many Tier 2s and Tier 3s rooted in “legacy” powertrain supply, as S&P Global analyst Michael Robinet has noted in his Supplier Eye column in this publication. But for Means Industries, whose clutch-technology IP is inside most automatic transmissions made worldwide, balancing today's business with tomorrow's propulsion opportunities has been part of the company's strategic roadmap for years.

Brooke, Lindsay

Controller Design for Path Tracking of Autonomous Vehicle Incorporating Four-Wheel Steering System

2022-01-0299

3/29/2022

This research aims to model and assess autonomous vehicle controller while including a four-wheel steering and longitudinal speed control. Such a modeling process simulates human driver behavior with consideration of real vehicle dynamics’ characteristics during standard maneuvers. However, a four-wheel steering control improves vehicle stability and maneuverability as well. A three-degree of freedom bicycle model, lateral deviation, yaw angle, and longitudinal speed is constructed to describe vehicle dynamics’ behavior. Moreover, a comprehensive traction model is implemented which includes an engine, automatic transmission, and non-linear magic formula tire model for simulation of vehicle longitudinal dynamics. A combination of proportional integral derivative (PID) longitudinal controller and fuzzy lateral controller are implemented simultaneously to track the desired vehicle path while minimizing lateral deviation and yaw angle errors. Then, A linear quadratic regulator (LQR) based rear steering controller is introduced to represent a performance improvement over front steering only. The longitudinal controller tries to maintain the desired speed through control of the engine throttle while the lateral controller steers the vehicle wheels to follow the pre-defined path. Path tracking simulation is executed through enjoining a referenced safe path to pass a simulated track based on ISO 3888 double lane change maneuver. Both longitudinal and lateral controllers’ simulation results achieved the required performance based on lateral deviation, yaw angle, front steering angle, and vehicle speed. Additionally, the lateral deviation is minimized according to the reference simulated path through the rear steering controller while decreasing vehicle yaw rate and slip angles for front and rear tires.

Gafar, Ibrahim, Oraby, Walid, Aly, Mahmoud Atef

A Work in Synthesizing Planetary Gear Trains for Plug-In Hybrid Electrical Powertrain Systems for Automotive Vehicles

2022-01-0654

3/29/2022

Planetary gear trains (PGT) are widely used in automatic transmissions (AT), hybrid electric powertrains (HEP) and plug-in hybrid electrical powertrains (PHEP) for automotive vehicles. Many PGTs have been developed by the industry including 6, 7, 8, 9 or 10 speeds automatic transmissions for internal combustion engine (ICE) powertrain systems; PGTs with two electrical machines (EM) and an ICE for single mode or multi-mode HEP systems; PGTs with single EM and an ICE for PHEP systems. Facing the new competitive challenges in motor vehicle electrification, synthesizing the simpler or if possible simplest PGTs for PHEP becomes an important task. The work reported in this article is such an effort which results in much simpler, if not the simplest, PGT designs for PHEP as well as for automatic transmissions. For example, with three planetary gear sets and five clutches, the work achieved all the following features with one integrated PGT design: seven gear ratios for ICE drive, four gear ratios for electrical machine (EM) drive, and a generator-assisted ICE vehicle launch operating mode which provides smooth vehicle launch operation without a traditional launch device (torque converter or launch clutch) when the electrical battery is depleted. Similarly, with four planetary gear sets and five clutches the following features are achieved: nine gear ratios for ICE drive, four gear ratios for EM drive, and generator-assisted ICE vehicle launch modes. With two planetary gear sets and five clutches the following feature are achieved: four gear ratios for ICE drive, four gear ratios for EM drive, and generator-assisted ICE vehicle launch modes. The design methodology and the details of the results will be reported.

Bai, Shushan

A New Design for Dedicated Hybrid Transmission (DHT) Product Platform Development Solution

2022-01-0670

3/29/2022

With increasing pressure for reduction in CO2 emissions and stricter fuel targets from road vehicles, OEMs around the globe have to electrify their vehicle range to meet increasingly challenging emission standards in recent years and new transmission technologies are gaining more attention in different main markets. The actual and future powertrain development has three major directions in order to reduce or avoid emissions in the transportation sector: Hybrid Vehicles: Hybrid Electric Vehicles (HEV), Plug-in HEV (PHEV) Electric Vehicles (EV); Range Extender Electric Vehicle (REEV); Fuel Cell Electric Vehicles (FCEV), Range Extender FCEV (REFCEV). This paper presents a new type Hybrid transmission which is called “DHT (Dedicated Hybrid Transmission)” technology for cost-effective HEVs and PHEVs; it permits the design of very compact automatic transmissions with an integrated high-voltage electric motor on the output side of the transmission. The new DHT has 2 speed ratios, outstanding economics, mechanically simple and very compact package for the challenging A- and B-Class segment’s fuel consumption and package requirements; all required and state of the art hybrid functionalities can be achieved. The new 2-speed DHT is a platform design and it can be easily changed to adapt to 1-speed DHT, 2-and 1-speed EDS (Electrical Drive System) for EV, and DET (Dedicate Electrical Transmission) for REEV system which can maximize use of the same common components in different platform products. This new 2-speed DHT platform design can significantly reduce time to market, product development costs, and production costs and at the same time increase vehicle configuration flexibility.

Xue, Xiang, Guo, Rong, Jiang, Xuyi, Hong, Ze

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