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The effect of vehicle transmission type on driver injury severities have not been thoroughly studied. The study used four-year historical crash data that occurred between the year 2019 and 2022 in Ghana. The data shows 1856 and 2272 crashes for automatic and manual transmission, respectively. The study examined the factors influencing driver injury severity in crashes involving vehicles with manual and automatic transmissions, using Random Parameter Mixed Logit Model to account for heterogeneity in the dataset. It was observed that use of manual transmission is related to a higher risk of incapacitating and fatal injuries compared to automatic transmission. Specifically, for automatic transmission vehicle-involved crashes, factors related to fatal injury were overaged vehicles, public transport, morning and evening peak hours, head-on and rollover crashes. Crashes involving saloon cars and low age cars were associated with incapacitating injury whiles rainy weather condition was related to both fatal and incapacitant injuries. Regarding manual transmission, fatal injury was associated with crashes involving male and novice drivers, cars, pickup trucks, HGV, public transports, morning and evening peak hours, rainy weather conditions and curved roads. Also, buses, private cars and trip distance were related to incapacitating injury. The rollover crashes and overaged vehicles were also associated with both fatal and incapacitating injuries. Four random parameters demonstrated heterogeneity in means, with two factors influencing the variances of two parameters for automatic transmission model. For the manual transmission model, five random parameters showed heterogeneity in means, with four variables influencing the variances of three parameters. These findings are valuable for policymakers, manufacturers, and drivers in implementing targeted interventions and safety measures to promote road safety.

Complex vibrational phenomena, such as gear impacts and mesh stiffness excitations, often require a significant amount of effort to be revealed using nonlinear analytical methods. However, key parameters for addressing vibrational problems can often be identified through simplified approaches based on linear analysis models. In light of these considerations, this study aimed to propose linear analytical methods to investigate the influences of various key parameters within symmetric systems. To achieve the main goal of this study, system modeling and eigensolutions were first implemented, focusing on a specific manual transmission with a front-engine/front-wheel configuration. Second, analytical techniques to reduce the number of degrees of freedom from the original symmetric system were suggested, and the reduced model was validated. Third, the system responses in the time domain were examined, along with key system parameters, such as gear mesh stiffness and clutch dampers, using state–variable equations. As a result, the findings from the linear system model demonstrated the fundamental dynamic characteristics of the torsional system within specific frequency regimes relevant to noise and vibration problems. Furthermore, the reduced lumped linear model employing the state–variable formula established its reliability in determining key parameters for mitigating noise and vibration problems. [ABSTRACT FROM AUTHOR]

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Complex vibrational phenomena, such as gear impacts and mesh stiffness excitations, often require a significant amount of effort to be revealed using nonlinear analytical methods. However, key parameters for addressing vibrational problems can often be identified through simplified approaches based on linear analysis models. In light of these considerations, this study aimed to propose linear analytical methods to investigate the influences of various key parameters within symmetric systems. To achieve the main goal of this study, system modeling and eigensolutions were first implemented, focusing on a specific manual transmission with a front-engine/front-wheel configuration. Second, analytical techniques to reduce the number of degrees of freedom from the original symmetric system were suggested, and the reduced model was validated. Third, the system responses in the time domain were examined, along with key system parameters, such as gear mesh stiffness and clutch dampers, using state–variable equations. As a result, the findings from the linear system model demonstrated the fundamental dynamic characteristics of the torsional system within specific frequency regimes relevant to noise and vibration problems. Furthermore, the reduced lumped linear model employing the state–variable formula established its reliability in determining key parameters for mitigating noise and vibration problems.

The effect of vehicle transmission type on driver injury severities have not been thoroughly studied. The study used four-year historical crash data that occurred between the year 2019 and 2022 in Ghana. The data shows 1856 and 2272 crashes for automatic and manual transmission, respectively. The study examined the factors influencing driver injury severity in crashes involving vehicles with manual and automatic transmissions, using Random Parameter Mixed Logit Model to account for heterogeneity in the dataset. It was observed that use of manual transmission is related to a higher risk of incapacitating and fatal injuries compared to automatic transmission. Specifically, for automatic transmission vehicle-involved crashes, factors related to fatal injury were overaged vehicles, public transport, morning and evening peak hours, head-on and rollover crashes. Crashes involving saloon cars and low age cars were associated with incapacitating injury whiles rainy weather condition was related to both fatal and incapacitant injuries. Regarding manual transmission, fatal injury was associated with crashes involving male and novice drivers, cars, pickup trucks, HGV, public transports, morning and evening peak hours, rainy weather conditions and curved roads. Also, buses, private cars and trip distance were related to incapacitating injury. The rollover crashes and overaged vehicles were also associated with both fatal and incapacitating injuries. Four random parameters demonstrated heterogeneity in means, with two factors influencing the variances of two parameters for automatic transmission model. For the manual transmission model, five random parameters showed heterogeneity in means, with four variables influencing the variances of three parameters. These findings are valuable for policymakers, manufacturers, and drivers in implementing targeted interventions and safety measures to promote road safety., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author.)

The influence factors of static shift performance and dynamic shift performance of manual transmission are analyzed. Because of requirements of gear shift performance test,the mechanical system and software system of transmission shift performance test rig are designed. Based on the developed test bench,static shift performance and dynamic shift performance test of a transmission are carried out. The static shift test shows that the designed test system can accurately measure performance parameters of transmission shift mechanism,such as track selection,gear clearance and select stiffness. The dynamic shift performance test shows that the designed test rig can measure performance parameters of shift force,lever travel and transmission input speed,and it can detected whether there are double bump in the shift process.

This paper presents the use and development of a specific wireless torque measurement system that is used to obtain the transient torque performance of vehicle transmissions. The torque sensor is strain-based, using surface-mounted strain gauges on a prop shaft. The gauges are connected to a compact printed circuit board, which is clamped to the shaft next to the strain gauges using a three-dimensional printed housing. The printed circuit board contains an amplifier, low-pass filter, analog-to-digital converter, microcontroller and bluetooth transceiver. The printed housing is impact resistant carbon-reinforced nylon and securely retains the printed circuit board and the battery powering the device. The transmitted torque data are received by a transceiver, which is interfaced to a PC through an RS-232 connection. NI LabVIEW is used to process, display and save data. The wireless torque sensor was installed to the Unit Under Test at the output shaft of the five-speed manual transmission. The Unit Under Test was installed on a dynamometer for verification purposes and the transient torque was recorded under various operational conditions. The transient output torque of the manual transmission is measured and compared with results obtained from simulations performed under similar operating conditions. The two sets of transient responses show a good correlation with each other and hence demonstrate that the torque sensor meets the major design specifications. The data obtained will be used to enhance the fidelity of the software model. [ABSTRACT FROM AUTHOR]

Synchronizers are the heart for the manual transmission, automated manual transmission and dual clutch transmission. The synchronizers match the speed of the target gears during gear shifts. Downsizing the high-power density engine develops higher angular accelerations. Higher angular accelerations create torsional vibrations and are detrimental to the life of the synchronizers. The synchronizer rings can move freely in the available space due to torsional vibration. The synchronizers which experience higher angular acceleration collide with the surrounding parts and wear out. The wear of synchronizer carbon liner reduces the wear gap to zero. The zero-wear gap hampers the synchronizer functionality and leads to gear clash. This paper presents the impact of angular acceleration on the life of carbon synchronizer ring and the parameters which are influencing to overcome the failure are studied. A bench test set-up was developed to simulate the vehicle level angular accelerations. The bench test results show direct correlation with the life of the synchronizer on the vehicle. Torsional vibration dampening using clutch size, oil viscosity, guiding of synchronizer ring, and oil volume are studied. The synchronizer carbon liner wear reduction is studied and validated with different bench and vehicle level tests. • Wear of automotive transmission gearbox synchronizer due to torsional vibration is a high threat to the vehicle endurance life. • Torsional vibration test rig simulates the vehicle synchronizer wear. • The test sequence involved in this study can be used to quickly solve the synchronizer wear problems. • The endurance life depends on the clutch size, synchronizer ring clearances, oil grade and oil volume. [ABSTRACT FROM AUTHOR]

The vibration and noise generation mechanism of the gear rattle in manual transmission is analyzed.According to the measurement of the size and the test of the NVH,the gear rattle in manual transmission is caused by the severe torque fluctuation of input shaft.The working principle of the dual mass flywheel（DMF） damping the gear rattle noise in manual transmission is analyzed.Through the experiment,the DMF can effectively damp the torque fluctuation of input shaft is verified,the gear rattle of the passenger car manual transmission can be controlled in a reasonable range as well.

The transmission efficiency of manual transmission and its effect factors are studied by using experimental method. A test bench of transmission efficiency is built,a testing sample is manufactured,and the transmission efficiency experiment is carried out. The test results show that when load torque remain constant,the transmission efficiency increases with the increasing of input speed,eventually reaches the maximum,then decreases gradually. Given the same input speed and load torque,the transmission efficiency is highest when its gearshift is switched to the fourth gear. When the input speed remain constant,the transmission efficiency increases with the increasing of load torque. When the viscosity-temperature characteristics of gear lubricant is improved by adopting multistage gear oil or synthetic gear oil,the comprehensive efficiency can be increased by 0. 62% and 0. 96% respectively. When open-type bearings are adopted to reduce the friction loss,the comprehensive efficiency can be increased by 0. 52%.

A method, which compares the angular acceleration and vibration spectrums of shafts and gears with physical characteristics of gearbox as tooth numbers and speed ratios, is proposed to find the source of gear rattle vibration. A mathematical and multi-body dynamics co-simulation model is built to reproduce the gear rattle phenomenon of one typical type of manual transmission. In the model, multi-body dynamics part is used for rotational motion and engagement simulation of gearbox shafts and gears, while mathematical part for control and data processing. The simulation results show that the sound source of the gear rattle from the first gear to the third gear is similar to the experimental results; different parameters like rotating damping, contact stiffness, contact damping, inertia moment and torque fluctuation making effects on gear rattle vibration strength are researched and simulated. The comparison of the simulation and experimental results shows that this method can provide recommendations for solving practical gear rattle problems. [ABSTRACT FROM AUTHOR]

Highlights • Gear ratios are calculated based on the basic vehicle parameters. • The whole method consists of a few consecutive steps, which are described in detail. • The formulas allow a vehicle to be designed with regard to dynamics and fuel economy. • The method enables simple and precise calculation of intermediate gear ratios. • Two stage calculations allow this method to be used by amateurs and professionals. Abstract The objective of this paper is to present an algorithm of gear ratio calculation in the manual transmissions of modern passenger cars. The paper presents all the necessary coefficients and formulas and thoroughly explains their influence on particular features of the vehicle, which are closely connected with its expected exploitation. These formulas result both from physical relationships and the performed analysis of vehicle dynamics, fuel economy, ergonomics and road characteristics. Every type of combustion engine, SI naturally aspirated, SI turbocharged or CI turbocharged, can be considered as vehicle propulsion. Particular emphasis is placed on a new method of gear spacing, which enables the simple and precise adjustment of intermediate gears. To quantitatively assess the dynamics and fuel economy of a specific construction, formulas for drawing the full throttle power characteristic and the characteristic of specific fuel consumption are provided. Moreover, a short and effective formula for calculating maximum vehicle speed has been developed. At the end of the work, there is a calculation example, which is an integral part of the article, showing the presented method on a particular vehicle. [ABSTRACT FROM AUTHOR]

This paper investigates the development of a mild hybrid powertrain system through the integration of a conventional manual transmission equipped powertrain and a secondary power source in the form of an electric motor driving the transmission output shaft. The primary goal of this paper is to study the performance of partial power-on gear shifts through the implementation of torque hole filling by the electric motor during gear changes. To achieve this goal, mathematical models of both conventional and mild hybrid powertrain are developed and used to compare the system dynamic performance of the two systems. This mathematical modelling is used to run different simulations for gear-shift control algorithm design during system development, allowing us to evaluate the achievable performance and its dependency on system properties. The impact of motor power on the degree of torque hole compensation is also investigated, keeping in mind the practical limits to motor specification. This investigation uses both the output torque, vehicle speed as well as vibration dose value to evaluate the quality of gearshifts at different motor sizes. Results demonstrate that the torque hole may be eliminated using a motor power of 50 kW. However, the minimum vibration dose value during gear change is achieved using a peak power of 16–20 kW. [ABSTRACT FROM AUTHOR]