Alternative control systems for mechanical transmissions of vehicles

ALTERNATIVE CONTROL SYSTEMS

FOR MECHANICAL TRANSMISSIONS OF VEHICLES

Anton KHRUSHCHEV (djerda@mail.ru)

Division of “Theory of  mechanisms and robot systems”

St. Petersburg State University of railway connections

Abstract

New directions in automatic transmissions of vehicles are considered and a justification of the topic is given. A concrete plan for the solution of the problems stated under constrain of minimal expenses is also given.

Keywords: automatic transmission, gear-box, automatic control system

Introduction

Nowadays automobile is not considered as something new and unusual. Passing through a long way of evolution automobile has transformed from the object of luxury to an everyday appliance. In the process of its formation automobile has undergone essential modifications. All its parts were changing: carcass, drive, carriage, and other parts including the transmission. At the beginning the transmission in all cars was mechanical which required and require (since such gear-boxes still exist and are successfully exploited at the present time) from a driver a considerable attention, driving experience and reaction. Therefore necessary attributes of cars with a mechanical transmission are the gearshift handle, and the friction pedal, which coupled with the accelerator pedal, break-pedal, and the steering wheel makes a rather complicated system of movement control. This circumstance is a big disadvantage of a mechanical transmission.

Actuality of the problem

Since the complexity of driving always affects driver’s reaction, it results in emergencies on the roads and consequently in accidents. The risk group includes in the first instance beginning drivers who do not have subconscious driver skills. This creates a big problem especially for modern megalopolises with their permanently increasing number of vehicles and the speed of movement. It looks on the first sight that the appearance of vehicles with semiautomatic and automatic transmissions apparently solved this problem. These vehicles do not have the friction pedal, which simplified their drive considerably. However, presently, this comfort is not cheap. For instance, in Russia there are not so many cars with automatic or semi automatic transmissions. The reason for this is a high cost of automatic or semiautomatic gear-box and of its installation. With respectively low prices on Russian cars the total expense of the automatic upgrade may reach up to 50% of the initial price for this car and sometimes even may exceed the this price. One can also mention the complexity of the automatic upgrade. In many cases it is prevented by constructive restrictions of a car. Since automatic transmission as a complex device including electronic ingredients, its service requires professional skills resulting for the overwhelming majority of drivers in the necessity to apply to a professional service.

Thus standard automatic transmissions together with obvious advantages related with simpler driving also have a number of serious shortages:

1.  High installation cost in some cases reaching up to 25% of the price of a new car;

2.  Big losses in the actual power of a car;

3.  Increase of fuel consumption;

4.  Constructive complexity and consequently a loss in reliability;

5.  Existence of a number of restrictions in the exploitation of a car with automatic transmission such as: it cannot be towed and must be transported, it has big problems in driving out of a road, any unnoticed defect in the engine may result in a serious damage for the automatic transmission followed by a very expansive maintains.

This leads to the conclusion that not every driver may allow himself or herself to have an automatic transmission whereas the problems related to mechanical transmission remain unsolved. In this relation one can say that the future of automatic transmissions, at least in Russia, is an upgrade of mechanical transmissions to mechanical transmissions equipped with a system of servomotors controlled by electronic devices. This concept eliminates the problems stated above and also provides an option of instant shift “automatic-mechanic” directly from the driver place.

A possible solution of the problem