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The assessment of the Transmission Loss (TL) of vehicle components at Low-Mid Frequencies generally raises difficulties associated to the physical mechanisms of the noise transmission through the automotive panel. As far as testing is concerned, it is common in the automotive industry to perform double room TL measurements of component baffled cut-outs, while numerical methods are rather applied when prototype or hardware variants are not available. Indeed, in the context of recent efforts for reduction of vehicle prototypes, the use of simulation is constantly challenged to deliver reliable means of decision during virtual design phase. While the Transfer matrix method is commonly and conveniently used at Mid-High frequencies for the calculation of a trimmed panel, the simulation of energy transfer at low frequencies must take into account modal interactions between the vehicle component and the acoustic environment.

Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed.

This paper describes advances in variable speed supercharging, including benefits for both fuel economy and low speed torque improvement. This work is an extension of the work described in SAE Paper 2012-01-0704 [8]. Using test stand data and state-of-the-art vehicle simulation software, a NuVinci continuously variable planetary (CVP) transmission driving an Eaton R410 supercharger on a 2.2 liter diesel was compared to the same base engine/vehicle with a turbocharger to calculate vehicle fuel economy. The diesel engine was tuned for Tier 2 Bin 5 emissions. Results are presented using several standard drive cycles. A Ford Mustang equipped with a 4.6 liter SI engine and prototype variable speed supercharger has also been constructed and tested, showing low speed torque increases of up to 30%. Dynamometer test results from this effort are presented. The combined results illustrate the promise of variable speed supercharging as a viable option for the next generation of engines.

A Dodge Omni electric car was prepared for competition in an electric “stock car” 2-hour endurance event: the inaugural Solar and Electric 500 Race, April 7, 1991. This entry utilized a series-wound, direct-current 21-hp electric motor controlled by an SCR frequency and pulse width modulator. Two types of lead-acid batteries were evaluated and the final configuration was a set of 16 (6-volt each) deep-cycle units. Preparation involved weight and friction reduction; suspension modification; load, charge and temperature instrumentaltion; and electrical interlock and collision safety systems. Vehicle testing totalled 15 hours of operation. Ranges observed in testing with the final configuration were from 30 to 52 miles for loads of 175 to 90 amperes. These were nearly constant, continuous discharge cycles. The track qualifying speed (64mph) was near the 68 mph record set by the DEMI Honda at the event on the one-mile track.

The mechanical energy of an engine is lost by engine friction and in driving the engine's auxiliary components, which is then transferred to transmission. Thus, it is very important to know the exact value of engine friction and the driving torque of engine's auxiliary components in order to reduce fuel consumption of an engine by reducing these losses. And, it is also helpful to know the braking torque of an engine in actual vehicle so as to improve vehicle's driving performance. For these reasons, present study developed an engine torquemeter for in-vehicle application, and measured braking torque of an engine in vehicle and analyzed fuel consumption contributions of engine's auxiliary components.

All vehicles have some or all accessories such as alternators, air conditioner compressors, power steering pumps, and water pumps. These devices are mounted on the front of the engine and are powered by a pulley mounted on the front of the crankshaft. This power represents a parasitic loss and this loss is greater at higher engine speeds. To reduce the impact of the accessories on the engine, a two speed transmission that reduces the accessories speed at off-idle conditions was designed, implemented, and tested on several vehicles. The vehicles were tested for fuel economy on the Japanese 10.15 Mode driving cycle, the FTP75 city cycle, and the HWFET Highway Cycle. Results showed an average of 5% reduction in fuel consumption and a corresponding 5% in CO2 with no impact of accessory performance and vehicle drivability. Simulations with GT-Drive software was used to determine the optimum speed reduction and the threshold switching speed that maximizes fuel savings.

Parallel Hybrid Electric Vehicle consists of internal combustion engine, engine clutch, motor, automatic transmission, Integrated Starter Generator (ISG), and battery. Due to hybridizations such as using engine clutch to disengage the internal combustion engine and omitting torque converter from the automatic transmission to increase fuel economy, drivability will not be same as conventional vehicle. To ensure drivability comparable to conventional vehicle, dynamic simulation has been utilized to foresee the drivability issues for the proposed hybrid system and ideas for improvements are tested in simulation. CoSimulation of AMESim vehicle model and Simulink Hybrid Control Unit (HCU) model has been used to test and improve HCU logic.

The VanDyne SuperTurbocharger (SuperTurbo) is a turbocharger with an integral Continuously Variable Transmission (CVT). By changing the gear ratio of the CVT, the SuperTurbo is able to either pull power from the crankshaft to provide a supercharging function, or to function as a turbo-compounder, where energy is taken from the turbine and given to the crankshaft. The SuperTurbo's supercharger function enhances the transient response of a downsized and turbocharged engine, and the turbo-compounding function offers the opportunity to extract the available exhaust energy from the turbine rather than opening a waste gate. Using 1-D simulation, it was shown that a 2.0-liter L4 could exceed the torque curve of a 3.2L V6 using a SuperTurbo, and meet the torque curve of a 4.2-liter V8 with a SuperTurbo and a fresh-air bypass configuration. In each case, the part-load efficiency while using the SuperTurbo was better than the baseline engine.

For transmission suppliers tooled primarily for producing manual transmissions, retrofitting a manual transmission with actuators and a controller is business viable. It offers a low cost convenience for the consumer without losing fuel economy when compared to torque converter type automatics. For heavy duty truck fleets even the estimated 3% gain in fuel economy that the Automated Manual Transmission (AMT) offers over the manual transmission can result in lower operational costs. This paper provides a case study using a light duty transmission retrofitted with electric actuation for gears and the clutch. A high level description of the control algorithms and hardware is included. Clutch control is the most significant component of the AMT controller and it is addressed in detail during operations such as vehicle launch from rest, launch from coast and launch on grades.

The US Army is currently seeking to reduce fuel consumption by utilizing fuel efficient lubricants in its ground vehicle fleet. An additional desire is for a lubricant which would consist of an all-season (arctic to desert), fuel efficient, multifunctional Single Common Powertrain Lubricant (SCPL) with extended drain capabilities. To quantify the fuel efficiency impact of a SCPL type fluid in the engine and transmission, current MIL-PRF-46167D arctic engine oil was used in place of MIL-PRF-2104G 15W-40 oil and SAE J1321 Fuel Consumption In-Service testing was conducted. Additionally, synthetic SAE 75W-140 gear oil was evaluated in the axles of the vehicles in place of an SAE J2360 80W-90 oil. The test vehicles used for the study were three M1083A1 5-Ton Cargo vehicles from the Family of Medium Tactical Vehicles (FMTV).

A new point of view in automatic transmission is proposed by R-R chart, which is a new analytic method based on the linearity of planetary gear and gear shift mechanism. The R-R chart is a visual tool to describe the whole motion of each rotational element of planetary gears in relation to the gear shift mechanism. Therefore, anyone can easily find on R-R chart not only the substance of the gear shift mechanisms in present automatic transmissions but also new gear shift mechanisms for the future automatic transmissions. This paper shows that the R-R chart is unique in 4-speed automatic transmissions with fixed compound planetary gear sets. As a result of the R-R chart application, this paper classifies the fixed compound planetary gear sets with 4 elements into 12 sets and the gear shift mechanisms into 3 types. Also, 4 R-R characteristic equations are derived as a correlation between speed ratios in 4-speed automatic transmissions.

In off-highway applications the engine torque is distributed between the transmission (propulsion) and other accessories such as power steering, air conditioning and implements. Electronic controls offer the opportunity to more efficiently manage the control of the engine and transmission as an integrated system. This paper deals with development of a steepest descent algorithm for maximizing the efficiency of hydrostatic transmission along with the engine in the presence of accessory load. The methodology is illustrated with an example. The strategy can be extended to the full hydro-mechanical configuration as required. Applications of this approach include adjusting for component wear and intelligent energy management between different accessories for possible size reduction of powertrain components. The potential benefits of this strategy are improved fuel efficiency and operator productivity.

In recent years there has been an increased interest in the continuously variable split power transmissions as these drive units are capable of vehicle launches and directional changes without using clutches. These tasks are accomplished by appropriately splitting power between the fixed mechanical and variable ratio branches. The power is recombined at the transmission output. A properly designed split power transmission arrangement will improve vehicular agility and reduce variator size. This paper provides characteristics of six single stage input coupled continuously variable toroidal split power transmission arrangements. Mathematical equations are derived for speed, torque and power. A computer program that utilizes the capabilities of Matlab is developed. The program calculates the required fixed and variable branch gear ratios for the predefined variator, planetary and overall transmission ratios.

Although the toroidal continuously variable transmission (CVT) has been successfully introduced into the automotive market, it has not been developed for the motorcycle community even though manufacturers have shown interest. Further, little information is available with regards to their application in motorcycles. To aid in the development process, continuously variable toroidal transmission design concepts for a motorcycle application are presented. Alternate packaging configurations developed in this paper represent potential future motorcycle transmission arrangements. Variator design parameters and their effect on transmission operation are discussed. Both single and dual cavity designs as well as orientation of the engine and final drive are reviewed.

Split power transmissions are often a viable power path for continuously variable powertrains. The planetary gear set is the central mechanism of these powerpaths which creates the possibility for numerous configurations. Determining the right configuration for a specific application can thus be complicated if the designer does not have an easy way to evaluate each configuration. This paper will address this issue. The different split power configurations are explored. Speed ratio and torque ratio formulas for the different configurations are introduced. An efficient and simple method to determine positive and negative power flow is also demonstrated. The development of tractive effort curves is discussed as a methodology to determine the theoretical performance of any configuration with an emphasis on the use of hydraulics as the variator.

Continuously variable split power transmissions can offer a clutchless transition from reverse through neutral and into the forward driving mode. This is accomplished by splitting the input power between fixed ratio and variable ratio branches and recombining the power with a planetary set. Further, these transmissions offer seamless ratio changes throughout their range. In contrast to these benefits, single stage designs can suffer from recirculated power, which increases the power level through the variator. This results in the need for a larger variator, which reduces efficiency and increases weight and inertia. In addition, single stage designs can experience high planetary member speeds as a result of a wide transmission ratio range. Seven dual stage input coupled transmission models are developed in an effort to reduce the recirculated power and high planetary member speeds found in the single stage designs. Speed, torque and power models are developed in Matlab and Excel.

This paper describes the development of a generic test cell software designed to overcome many vehicle-component testing difficulties by introducing modern, real-time control and simulation capabilities directly to laboratory test environments. Successfully demonstrated in a transmission test cell system, this software eliminated the need for internal combustion engines (ICE) and test-track vehicles. It incorporated the control of an advanced AC induction motor that electrically simulated the ICE and a DC dynamometer that electrically replicated vehicle loads. Engine behaviors controlled by the software included not only the average crankshaft torque production but also engine inertia and firing pulses, particularly during shifts. Vehicle loads included rolling resistance, aerodynamic drag, grade, and more importantly, vehicle inertia corresponding to sport utility, light truck, or passenger cars.

The promising D-EGR gasoline engine results achieved in the test cell, and then in a vehicle demonstration have led to exploration of further possible applications. A study has been conducted to explore the use of D-EGR gasoline engines as a lower cost replacement for medium duty diesel engines in trucks and construction equipment. However, medium duty diesel engines have larger displacement, and tend to require high torque at lower engine speeds than their automobile counterparts. Transmission and final drive gearing can be utilized to operate the engine at higher speeds, but this penalizes life-to-overhaul. It is therefore important to ensure that D-EGR combustion system performance can be maintained with a larger cylinder bore, and with high specific output at relatively low engine speeds.

The market demands for CO2 reduction and fuel economy have led to a variety of new gear set concepts of automatic transmissions with 4 planetary gear sets and 6 shift elements in recent years. Understanding the relationship between the torque of clutch and brake and gear ratio in the design stage is very important to assess new gear set concepts and to set up the control strategy for enhancing shift quality and to reduce the heat generation of clutch and brake. In this paper, a new systematic approach is used to unify the relationship between torque and gear ratio during the gear shift for all multi-step planetary automatic transmissions. This study describes the unified concept model with a lumped inertia regardless of the specific transmission layout and derives the principal unified relationship equations using torque and energy analysis, which prove that the sum of brake torque is always gear ratio -1 in every in-gear.

This study presents the NVH characteristics of a passenger vehicle with a three-cylinder engine and a Continuously Variable Transmission (CVT) and an optimization procedure to achieve balance between fuel economy and NVH. The goal of this study is to improve fuel economy by extending the lock-up area of the damper clutch at low vehicle speed and to minimize booming noise and body vibration caused by the direct connection of the engine and transmission. Resonance characteristics of the chassis systems and driveline have been studied and optimized by the experiment. NVH behavior of the vehicle body structure is investigated and modifications for refinement of booming and body vibration are proposed by simulation using MSC NASTRAN. Calibration parameters for CVT control are optimized for fuel economy and NVH. As a result, the lock-up clutch area has been extended by 300RPM and the fuel economy has been improved by about 1%, while the NVH characteristics of the vehicle satisfy the targets.