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I am Adam Feneley, studying for an MEng in Motorsport Engineering at Brunel University, England.

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22 Apr 2011

Vehicle Design: Piston Design 101



This article provides a truly comprehensive look at the design considerations for pistons. Further articles are available which provide a look at piston rings, the connecting rod and many other components. Select the '101 guides' or 'vehicle design' category in the right hand sidebar lower down the page. Anyway onto the article:
Fig 1: Labelled image of a piston and con-rod.

The two main requirements of the piston are as follows:
  1. Contain all the fluids above and below the piston assembly during the cycle.
  2. Transfer the work done in combustion to the connecting rod with minimal mechanical and thermodynamic losses.


They key thing to note about piston design for absolutely any application regardless of the field is that it is HUGELY dependent upon the task that the engine will be required to fulfill.  The pistons for a 1000 horse-power racing car will be designed differently and made from different materials than pistons that are used inside a tractor for example. The shape of the piston crown (see diagram above) can also vary dependent on the type of engine you are dealing with as they can be used to change flow characteristics within the cylinder. The crown of a piston in a diesel engine is likely to look different to the piston of a petrol engine, especially in high performance applications.  Despite this all pistons need to obey the following;

Five Key Properties of a Piston:
  1. Sufficient thermal conductivity
  2. Low thermal expansion
  3. High hot strength
  4. High strength to weight ratio
  5. High resistance to surface abrasion


A few definitions for the terms that are mentioned above:

Thermal conductivity: The ability of a material to absorb heat without causing damage or significant change to the materials microstructure or properties.
Thermal expansion: How much the material will expand when heated.
Hot strength: Ability to withstand stress, strain and shear at temperatures higher than room temperature. (Piston temperatures will be covered later in this article).
Strength-to-weight ratio: Fairly obvious this one, ideally we want a very light material with very high strength, the lighter and stronger the better.
Surface abrasion: The rate at which material wears due to rubbing on the surfaces of it, surface treatments can be added to metals to increase the surface toughness and make them more resistant to this.

The piston is obviously one of THE key components in any engine; it provides the seal, which enables power to transfer to the crankshaft so an effective design is key.

Heat is one of the biggest problems faced when designing a piston, an example of typical road car piston temperatures and their distribution is shown below:

Fig 2: Typical temperature map for a piston
So n the crown of the piston the temperatures tend towards around 250 – 300 degrees Celsius and gradually decrease the further from the combustion you go. The second key property I mentioned earlier was that pistons should have a low thermal expansion; this is because at these temperatures pistons will expand, especially on the crown and the top of the skirt. Because of this, pistons are actually tapered, although it is not obvious with the naked eye pistons are wider at the bottom of the skirt than the top to allow for expansion at the crown. If this was not done then when the piston expanded then it could potentially become too wide to fit within the cylinder.

Piston temperatures also vary with speed, which is key to note for higher performance engines, since at 1500 rpm a piston crown can be around 100 degrees Celsius cooler than when the engine is providing 5000 rpm. Piston spray jets may be added to engine in these high performance engines in order to lower the temperature of the crown. These feed of the main oil gallery and usually provide between one half and one litre per minute.

Piston Materials:                   PROS                                       CONS

Cast Iron                                Hot strength                          Mass
                                                Hardness                               Thermal conductivity
                                                Thermal expansion

Aluminium Alloys                  Mass                                       Thermal expansion
                                                Strength-to-weight                Hot strength
                                                Thermal conductivity            Hardness

Carbon Fibre Reinforced     Mass                                        Cost
Carbon (CFRC) -                    Strength-to-weight                Operating issues
(Research use only)              Hot strength
                                                Thermal expansion



The operating issues mentioned with the CFRC pistons include hydrocarbon emissions, since the material used for the piston has been observed to absorb fuel particles and then release them in the exhaust causing unwanted pollutants, this is also a knock problem with this technology. However it must be pointed out these pistons are purely experimental at the moment and engineers are experimenting with materials in an attempt to come up with better compounds. 

Manufacturing Effects:

To demonstrate the effects of manufacturing effects on the performance of a piston we will focus on only aluminium pistons, however similar effects follow across most metals.

For spark injection engines, cast aluminium can provide an intricate part at relatively low cost and low weight. Forged aluminium however can provide a finer microstructure and therefore higher strength when compared to casting, albeit more expensive.

Due to the additional pressures occurring in a diesel engine (since the fuel is self igniting) the pistons require local reinforcements. For example, a cast aluminium piston for a diesel engine would be made from a higher temperature alloy than for a petrol engine, and the following reinforcements may be applied:
  • Refined casting methods; finer microstructure around the bowl (crown).
  • Insertion of high strength cast iron piston ring carriers.
  • Insertion of bushes into the pin bores.






That is the end of the main piston design article, further articles going in depth into the design of piston rings, connecting rods and loads of other major components are available in the '101 guides' and 'vehicle design' categories found in the right hand side bar. Thank you for reading and please feel free to comment any questions about this subject or any other topic you'd like to see me write a guide to. 


By Adam Feneley,

Brunel University
MEng Motorsport Engineering (Level 2)
Affiliate of the Institute of Mechanical Engineers

April 2011



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8 Apr 2011

2011 F1 Malaysian Sepang Grand Prix - Preview





An Unprecedented Home Grand Prix for Three Formula 1 Teams


With three Formula 1 teams ‘carrying’ the Malaysian flag, the 2011 Formula 1 PETRONAS Malaysia Grand Prix will indeed be a special one for Malaysians.


“F1 has always been a special event for Malaysia. This year, however, it is even more extraordinary,” says Malaysian Prime Minister Datuk Seri Mohd Najib Tun Razak in reference to the alliance of Malaysian corporate companies with the Mercedes GP PETRONAS, Lotus Renault GP and Team Lotus.
“Never has the event been associated with so many Malaysian companies; making the 2011 Formula 1 PETRONAS Malaysian Grand Prix and Sepang Circuit as their ‘home race’ this season,” Najib said in his message at in the event’s official programme.
2011 marked the 13th edition of the Formula 1 PETRONAS Malaysian Grand Prix, which traced back to 1999 when it was first developed as tourism tool to sell Malaysia as an international destination and a national agenda to uplift the country’s image worldwide.
The new season opened at Albert Park in Melbourne with the Australian Grand Prix on March 27 and Malaysia hosts Round 2 of the 2011 Formula 1 World Championship, which now runs for 19 rounds with the cancellation of Bahrain Grand Prix.
Najib said: “Malaysia’s interest and its glorious image will be prominently projected this year, throughout all the rounds across the globe through the participation of Mercedes GP PETRONAS, the Proton-backed Lotus Renault Racing; the 1Malaysia Team Lotus as well as Virgin Formula 1 Racing, which has Q-Net as one of its key partners this season.
“Formula 1 – the world’s most prestigious motorsports event; and Malaysia’s tool in promoting the country for so long – is now adopted by more Malaysian companies as their business tools as well,” he said, adding that before Sepang Circuit came into the picture in 1999, Malaysia had Tourism Malaysia riding the popularity of the Stewart Grand Prix team in 1997.
Before that PETRONAS became the presenting sponsor for Red Bull Sauber in 1995. Over the years, the national petroleum company expanded further its investment in the sports including becoming the title sponsor for the Malaysian race and deeper involvement in the F1 racing teams.
Najib said: “With an extensive global audience; reaching hundreds of millions televisions on Race Day alone, the sport is undoubtedly the most effective platform for international mileage and worldwide recognition. Apart from global branding, it’s also the place for business networking, a stage to showcase a country; and an engine for transfer of technology. As such, for Malaysia, as a nation aspiring to be a major player in the automotive industry, its deep association with Formula 1 is only natural.
“Malaysia is always proud to be associated with Formula 1. We are proud to be the second Asian nation after Japan to host this prestigious event and inspired other Asian nations to bid for the privilege as well. Our current contract runs until 2015; and we aim to make full use of this privilege to reap in the fruits of benefits. And, to date, the impact of Formula 1 for Malaysia has been tremendous,” he added.
For Youth and Sports Minister, Datuk Seri Ahmad Shabery Cheek, the Formula 1 PETRONAS Malaysian Grand Prix was proof Malaysia’s capability in organizing world class motor racing events; and he hoped that it would be reflected as well in the competition field as well.
“Formula 1 has always been a special event in Malaysia; and the Malaysian Government has always been proud to be associated with the prestigious event. And, we, Malaysians, are truly privileged that have this event here at our own backyard.
“From the first race on October 17, 1999 and 11 editions later, the Formula 1 Petronas Malaysian Grand Prix had been a success story for Malaysia. It had transformed Malaysia’s status in the international arena; generated massive tourism dollars as well as jumpstarting the motorsports industry.
“Not too long ago, we would have never imagined of Malaysians competing in international races. But, after the establishment of Sepang Circuit in 1999, the perspective definitely changed – there’s was renewed confidence; and there was enhanced commitment among Malaysians,” he said.
He related the days of PETRONAS Sprinta Yamaha Team TVK venturing into the GP World Championship in 2000, to the introduction of Alex Yoong as Malaysia’s first F1 driver in Alex Yoong, the teenage Jazeman Jaafar dominating the Formula BMW Pacific series and Fairuz Fauzy role as an F1 test driver.
Declaring that he saw good prospects for the future, Shabery said that he believed with the continuous commitment and persistent effort, motor racing, too, could produce Malaysian world beaters
“We are proud to have world class athletes in badminton, squash, cycling and bowling. And, I strongly believe we can have world class performers in motor racing as well; especially with the current emphasis that Malaysian corporate companies are giving to the sports,” he added.
While welcoming the strong alliance of the Malaysian companies in the F1 teams, the minister hoped that the corporate companies involved would look at their partnership more than just from the business perspective.


“I sincerely hope that it would be translated into programmes for motorsports development as well,” said Shabery, who hailed SIC’s successful efforts in incorporating the Malaysian Super Series as support races for the 2011 Formula 1 PETRONAS Malaysian Grand Prix.
Hailed as the national championship for track racing and introduced in 2002, the MSS would be running the Malaysian GT class and the Malaysian Touring Car Challenge at the F1 race in Sepang as its opening round for its 2011 season.
In his message, SIC Chairman Datuk Mokhzani Mahathir said: “I am very happy that we finally managed to incorporate our Malaysian Super Series as the support races for the F1 event in Sepang. This is a racing series that we, at Sepang International Circuit, had diligently nurtured for years as the national championship for track racing; and the platform to provide top class competition for the drivers and teams.
“Together with our two other major events – the 12-hour Merdeka Millennium Endurance Race and the 1000-kms Endurance, these are the events that we hope for Malaysians to pick up their skills in managing and operating motor racing teams as well as to unearth new talents.
“Through these events, we aim to create a new culture of motorsports among Malaysians especially the grassroots, added Mokhzani.

Driving like an F1 driver on normal roads can be dangerous, but that doesn't stop some people. If you have been in an accident because of someone's dangerous driving and you want to know more about car accident compensation claims, then visit www.roadtrafficaccidentsite.com.
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1 Apr 2011

Photo Gallery: 2011 F1 Cars - All Teams




This stunning gallery of images documents the latest 2011 models of all 12 of the teams in this seasons F1 World Championships.  For more info on rule changes see this article: link

Please also take time to vote on who you think will be successful this year, there are a set of three polls on the right-hand sidebar which include views on who will win the constructors and drivers championships and who will be the best 'new' team!


Ferrari F150th Italia - 2011 Season F1 Car


Force India VJM04 - 2011 Season F1 Car

HRT (Hispania Racing Team) F111 - 2011 Season F1 Car

Virgin Racing MVR-02 - 2011 Season F1 Car

McLaren Mercedes MP4-26  - 2011 Season F1 Car

Torro Rosso STR6 - 2011 Season F1 Car

Williams FW33 - 2011 Season F1 Car

Red Bull Racing RB7 - 2011 Season F1 Car

Mercedes GP Petronas MGP W02 - 2011 Season F1 Car

Renault Lotus R31 - 2011 Season F1 Car

Sauber C30 - 2011 Season F1 Car

Team Lotus T128 - 2011 Season F1 Car
»»  read more

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