The first time I heard of charging double (both with a turbocharger and a compressor on the same engine) was probably in 2000. At that time I was very interested in the performance of the Toyota Celica and, of course, I also read a lot about his sister's car (shared with some of the engines themselves), like the Camry and MR2.
One of the most interesting parts aftermarket, which at the time I spent was driven by the HKS turbo kit for the first generation 4AGZE Mr2. The 4agze(For those not familiar with Toyota engines), a peppy 170 horsepower 1.6-liter is Toyota SC-12 roots-type compressor driven. On this car, Toyota uses a compressor electromagnetically tight, that could be disabled during the low power requirements such as cruise, and is active when the user requests it.
One of the most important parts of the kit is the HKS bypass valve. This valve was used to draw air from the compressor directly to the engine at low speeds / flow points.As soon as the speed increases, and the engine begins to demand more air, and the turbocharger is fully wound, turn the valve slowly until the turbo feeds the engine alone, while the compressor is completely bypassed. The twin-turbo MR2 have been rumors about the 300 HP mark, in some cases to break, depending on the level and support the final push for changes, and the level of performance for a 1.6 liter engine with time has amazingly quiet.
The theory behind this type ofSystem is a small positive displacement (roots style) use of the compressor. Performance of the compressor efficiency is usually highest at low speeds and compressor (for example, from idle to 4000 rpm). Above 4000 rpm, performance and efficiency of the compressor begins to fall, the power required to drive begins to rise exponentially, and the temperature begins to rise dramatically from the compressor to limit the performance.
On the other hand, with agenerously sized turbocharger will allow us to efficiently power the engine with cooler air (revised from a compressor) and maintain high-speed performance. The problem with using a turbocharger that a larger-sized turbochargers spool usually no earlier than 3000-4000 rpm power band is our limited and therefore does not increase performance at low speed.
The idea is to use a dual boot, is a compressor and turbo charger to have anywhat they do best are the compressor motor to increase torque at low revs, and when its vapor, the turbocharger comes to us in line to contribute to the red line.
There are three aspects of these types of systems that make them inaccessible for most tuner:
1 Costs and Complexity: With a turbo compressor and a complete system fully on the same vehicle and spend a lot of money to deal with a lot of parts and diagnose, if not go a little 'wrong.
2 The bypass valve used to control the compressor (and still maintain all air pressure from the turbocharger) and in a position, this valve is electrically or mechanically requires a bypass valve that only custom all available in stock. Although as I write this, it seems possible, a large-scale two-chamber bypass valve plumbed to the pressure difference between the output of the turbo compressor and the outlet to find running as soon as the conversionBoost pressure = pressure + charging voltage of the bypass valve opening mechanism.
3 Since we are using two different types of charger efficiency with two different boards, can be very complicated to figure out how to tune the engine (especially with a lot more simple injection systems that were used at the time) because the density of the air can vary greatly at the same speed and pressure-point level, depending on the charger to the air intake of the engine and in whatShare. This applies even if the HKS turbo kit for 4agze was weaker, that is, to facilitate the transition point between the supply switching turbo charger.
One of the things that has changed in the last 10 years is the availability (and dissemination of knowledge) available on alternative fuels or octane booster. Two options, which are:
1 - E85, which is composed of 85% ethanol, which has an octane rating of about 100-105 octane vs. typical87-93 octane pump gas.
2 - water / methanol injection systems as well as an additional supply system (based on the content of methanol, which carries an octane rating of 110 octane) may be used or to be used for the in-cylinder cooling when the water vapor injected with methanol converted into steam inside the combustion chamber, in order to extract more heat from the combustion chamber, thus slowing the speed of the flame before simulationeffects similar to those of a higher octane rating.
With the availability of these increases octane or octane concoctions simulation, has become more accessible to fans last performance to create a different kind of double-loading system, which does not build a bypass valve.
Driven in this type of system, the Charge is to feed the turbocharger inlet, or vice versa. Instead, both the turbocharger compressor or engine powerindividually (in parallel) and switching between the two, now we are using a two-stage compression phase in which a compressor factory, and the second stage is an aftermarket turbocharger system.
The result of the two compressors is a pressure cap. For example, when the turbocharger wastegate opening spring is an attitude of 7 psi above atmospheric pressure (which is a given pressure of 1.5 to 1 atmosphere of about 14.7 psig) together, and ifThe compressor is mechanically aligned to 50% more than the engine (for positive displacement compressors roots style) flow at any speed, so that an environment identical to 7 psi boost, or a print-ratio of 1.5, then combined ratio resulting pressure of the system is as follows:
PR PR PR * Total = turbo compressor, a pressure ratio of 2.25 =
A pressure ratio of 2.25 corresponds to 18.4 psi increase (not counting the 14 psi with the addition of two stages combined).
In any case, how it worksare based on octane requirements?
When the turbocharger, the power of the compressor, for example, the turbocharger and the intake of fresh air at room temperature (T1), then:
1 - The air leaving the turbocharger will be at a temperature T2, higher than the temperature (T1) of about 60-80 * C depending on the exact turbocharger, and where we are on the compressor map and turbocharger efficiency.
2 - The air enters the compressor at a temperature T2~ T3 T1 = 60 and quit at a temperature which is greater than T2 for more than around 60-80 * C, depending on the exact specifications of the compressor.
3 - If we had an intercooler after the compressor, then the air in the intercooler is 120 to 160 * C above ambient temperature, which is a lot of heat for the air cooling of the attempt to be cast in the short time that the air the intercooler core.
4 - When there are post-intercooler (thecommon on cars, where the compressor is packed into the intake manifold of the car), then the air in the engine will be some 120-160 * C above ambient temperature.
5 - The excessive heating of the air not only reduces the performance (about 1 hp for every 13 * C), but also increases the likelihood of air-fuel mixture is ignited in the engine automatically maturity before the spark plug has fired and if This premature ignition occurs early enough to take the pistonsignificantly away from top dead center, then fight the flame front push the plunger down, and the inertia of the system (the rotation of the cylinders and the power of fire of the other pistons on the crankshaft), pushing the plunger up to the door extremely high pressures and temperatures increase in damage on the surface of the piston to the end and possibly damage to other parts of the engine as well.
For these reasons (compounding pressure, increased temperature and combined) sequenceLaden is little used in the past. Using a higher octane rating means by definition that the air-fuel mixture is less susceptible to self-ignition and explosion. Moreover, in case of premature ignition, the higher octane creates more slowly traveling flame front, which gives the piston more time to go to the top of the cylinder bore (closer to TDC) before the meeting of the flame front, and this reduces the time that the surface of the piston is wrongPressure hot and reduces the possibility of a fatal error. Last but not least, concerns the use of a water / methanol injection mixing of two phase-change events:
1 - Methanol injected from liquid to gaseous state at its boiling point of 65 * C, ie, as soon as the mixture of compressed air blows out of the compressor. This phase change is taking up most of the heat from the air and methanol reduces the temperature of the firstMixture enters the combustion chamber and begins to compress. This temperature reduction is a long way to eliminate or greatly reduce the chance of detonation.
2 - The injected water from liquid to gaseous state at its boiling point of 100 * C, which depends on the availability of an intercooler in the system, my experience in the intake pipe before it reaches the combustion chamber, or will not be made until the mixture is ignited. In both cases, if theThe temperature is high enough, the mist of water injected into the flash airflow to evaporate into steam and consumes a large amount of heat produced during combustion.
The availability of these octane boosters now makes it possible to provide aftermarket parts manufacturer for the performance of a kit of safe, reliable load sequentially to the mass market.
This kit that I came across an article in Hot Rod Magazine Power was developed by hellion(Http: / / www.hellionpowersystems.com) mustang supercharged engine for the production of GT-500.
The kit said to produce up to 1000 horsepower at a boost pressure of 24 psi Turbonetics turbo with two 61 mm.
To achieve this, about 1000 HP 1500 cfm of airflow at 24psi or 1500cfm requires, at a pressure ratio of 2.63, or 750cfm@2.63pr to the turbocharger.
Since most tickets for this turbocharger compressor size (61 mm) peak at around 600cfm@2.63 pr @ 50% efficiency, which is aoutermost point on the map (for example, the turbo is maxed out at that point). I must say that I'm confident that the kit can support a pair of 61 mm turbo 800hp'm typical, but even if he proves 1000PS has happened, not what most agree released 61mm turbocharger. I'm not questioning the kits, I'm saying that I do not use a better reference for the specific turbocharger in the kit.
In addition, the power injector requires eight 8 1000PS 750cc/minInjectors in my opinion, and this agrees with what is necessary to Hot Rod Magazine Article 75lbs/hour injectors (for lb / h is roughly equivalent to 10.5cc/min) to a minimum or total fuel demand, supply above 900 liters of fuel per hour with fuel manifold pressure, usually around 45psi.
Given the extent of the fuel pump 255lph @ 30psi GS342 with a kit is provided, then with three gas stations gives us the ability to 765lph which is about2125 HP worth of fuel, so in that respect, the kit is able to support the figure of power.
As you can see, it is possible that such a complex project, if the information (turbocharger compressor map, temperature map turbocharger, compressor, compressor map, the map of the temperature of the compressor, etc. ...) first-hand information was available. What remains a mystery and art of trial and failure is how your engine is over-engineered to produce as much torque and furtherto survive and how long you can continue to survive at high levels. This is a question to be answered more interesting overall.
0 comments:
Post a Comment