Archive for the ‘transmission’ Category

Formula One CVT (Part 2)

Tuesday, August 17th, 2010

transmissionIn the previous article, we looked at the prototype Formula One constantly variable transmission (CVT) system that Williams developed in conjunction with Van Doorn in the early 1990s, and spoke to engineer Arnaud Boulanger who was involved with the project.

Anyone who follows Formula One closely will remember the dominant position that Williams had at that time. The CVT’s development happened during a golden era for Williams; having the best car, they attracted the best drivers and for years were considered ‘kingmakers’ owing to the fact that, more often than not, the world champions drove a Williams. Read more…

Transmission

Friday, July 2nd, 2010

transmissionsMore than 15 years ago, a young David Coulthard said he was “very excited” about a new development at Williams, going on to say that “machine is working better than man”. The reason for his enthusiasm was that he had just tested Williams’ revolutionary continuously variable transmission (CVT) system. This was in 1993, and the system so worried other competitors and the FIA that it was banned before it could be raced. There is video on the internet of the car being tested in CVT guise, and it is well worth watching - and listening to. Read more…

Transmitting power

Thursday, May 13th, 2010

transmissionWith the adoption of independent, or de Dion rear suspension by racing car constructors during the 1930s, some means of transmitting the torque from the transmission into the wheel hubs had to be devised that accommodated the vertical motion of the wheel.

When using a swing axle, this was usually achieved by using a ball-and-socket arrangement integrated into the differential output shafts, while fully independent and de Dion systems required some form of universal joint at each end of the driveshaft. Read more…

Using tractive effort curves to analyse gearing

Wednesday, March 31st, 2010

transmissionsIn the last edition of Monitor we introduced the concept of ‘Tractive Effort’ curves plotted against road speed to analyse performance.

Most ‘racers’ are familiar with using the traditional straight line plot of road speed against engine rpm as a method of choosing ratios. Whilst this gives an indication of maximum speed in each gear and helps to assess the drop in engine rpm associated with changing up into the next ratio, its use is otherwise limited. In particular it does not

Read more…

Tractive Effort

Tuesday, February 16th, 2010

transmissionIn recent RET-Monitor features we have considered several aspects of transmission design and engineering, each time with the implicit assumption that some means of gearing between the power unit and road wheels was a prerequisite feature.

Why should this be so, and how do we then determine what we need?

Essentially we seek to transform rotational motion Read more…

TRANSMISSION AND DRIVELINE OFFSET

Thursday, January 21st, 2010

transmissionOne of the problems faced by race car designers is the conflicting requirement of keeping a low centre of gravity for the engine (and transmission), whilst keeping the driveshaft within acceptable values. Whatever the chosen method of coupling excessive angularity will lead to increased power losses and ultimately, failure of the joints.

Putting some numbers to this, consider a Formula Three car whose engine is dry sumped and running a 140 mm diameter race clutch on a lightweight flywheel. Read more…

The Pull Clutch

Saturday, December 19th, 2009

transmissionThe appearance of the pull type clutch in the race car world in the last decade was driven mainly by considerations of efficiency, consistency, and component life. These factors are improved by an increase in the mechanical advantage of the release mechanism.

Starting with the basic operation of a conventional ‘push’ clutch, the ‘push’ that is delivered by a slave cylinder refers to the force that is required to disengage the clutch plates. Upon depressing the clutch pedal, hydraulic fluid is forced into the cylinder which is then thrust out Read more…

Trends in Race Clutch Design

Sunday, November 15th, 2009

transmissionThe traditional race car multi plate clutch is essentially a friction drive that transmits engine torque into the transmission itself. Layers of plates are alternately geared to the clutch housing, which is bolted to the engine flywheel and also to the clutch hub, which is splined to the gearbox input shaft. When a heavy axial, or clamp load is applied to the assembly, the friction produced between plates prevents any rotation between them and we have a solid drive without any additional mechanical engagement. Transmitting this drive depends on maintaining the clamp load. This is usually obtained by Read more…

SEQUENTIAL GEARBOX ORIGINS

Monday, October 12th, 2009

transmissionIn previous Monitor features we have touched upon the automated gearshift of a modern race car and attempted to put it into historical context, but how many of its mechanical design features represent new thinking ?

Central to its function has been the move from a H-gate to sequential gear selection, for with this it is much easier to provide powered control of the actual selection mechanism. In the modern box this normally takes the form of a drum, with a pathway machined into it, whose axis is parallel to that of the actual gear shafts. Read more…

The origins of the modern race car gearbox?

Monday, September 14th, 2009

transmissionUp until the end of the 1950s, when the front engined Grand Prix car predominated, it was not uncommon to find it’s transmission attached to the engine bell housing, in classic road car configuration, with the box itself almost always in-line, and often road car derived. But it was equally the norm to find the transmission in unit with the rear axle and differential, particularly in a thoroughbred racing design, in which case it was as common for it to be aligned transversally, as in-line.

When the mid-engined car began to take over Read more…