Tuned engine

Combustion of the octane in a poorly tuned engine can produce toxic carbon monoxide along with the usual carbon dioxide and water. In a test of an automobile engine 1.00 L of octane (702 g) is burned, but only 1.84 kg of carbon dioxide is produced. What is the percentage yield of carbon dioxide ... 

A well-tuned engine improves a car s performance and limits fuel consumption. 

The standard Gibbs energy of combustion of glucose is -2880 kJ mol , so terminating its oxidation at pyruvate is a poor use of resources, akin to the partial combustion of hydrocarbon fuels in a badly tuned engine. In the presence of O2, pyruvate is oxidized further during the citric acid cycle and oxidative phosphorylation, which occur in the mitochondria of cells. 

A well-tuned engine or balanced musculoskeletal system is capable of good performance. It s prepared to accommodate the traveling fetus by regulating its own contractions and assisting the muscles to cooperate with the flexion, extension, and rotations of the fetal skull By maintaining the body... 

Many misconceptions exist about cascade control loops and their purpose. For example, many engineers specify a level-flow cascade for every level control situation. However, if the level controller is tightly tuned, the out-flow bounces around as does the level, regardless of whether the level controller output goes direcdy to a valve or to the setpoint of a flow controller. The secondary controller does not, in itself, smooth the outflow. In fact, the flow controller may actually cause control difficulties because it adds another time constant to the primary control loop, makes the proper functioning of the primary control loop dependent on two process variables rather than one, and requites two properly tuned controllers rather than one to function properly. However, as pointed out previously, the flow controller compensates for the effect of the upstream and downstream pressure variations and, in that respect, improves the performance of the primary control loop. Therefore, such a level-flow cascade may often be justified, but not for the smoothing of out-flow. 

Fig. 2. Effect of mixture strength on exhaust gas composition (dry basis) and brake specific fuel consumption (BSFC) for an unsupercharged automotive-type engine usiag iadolene fuel, H/C = 1.86, where the ignition is tuned to achieve maximum best torque (MBT), the brake mean effective...

The above FF controller can be implemented using analog elements or more commonly by a digital computer. Figure 8-33 compares typical responses for PID FB control, steady-state FF control (.s = 0), dynamic FF control, and combined FF/FB control. In practice, the engineer can tune K, and Tl in the field to improve the performance oTthe FF controller. The feedforward controller can also be simplified to provide steady-state feedforward control. This is done by setting. s = 0 in Gj. s). This might be appropriate if there is uncertainty in the dynamic models for Gl and Gp. 

Control of diesel-powered vehicles is parhally accomplished by fuel modification to obtain reduced sulfur content and cleaner burning and by proper tuning of the engine using restricted fuel settings to prevent overfueling. 

Roliani, S. and Bourne, J., 1990b. Self-tuning control of crystal size distribution in a batch cooling crystallizer. Chemical Engineering Science, 45, 3457-3466. 

The emissions reductions provided by the catalytic converter also allowed engineers to re-tune their engine designs and add an improved proportional EGR system. By modifying the EGR that recycles exhaust in proportion to intake air (as a function of engine speed) rather than at a constant rate, emissions could be better controlled over a wider range of oper-... 

Self-Test 4.7B An idling, badly tuned automobile engine can release as much as 1.00 mol CO per minute into the atmosphere. At 27°C, what volume of CO, adjusted to 1.00 atm, is emitted per minute ... 

Carbon monoxide, CO, is produced when carbon or organic compounds burn in a limited supply of air, as happens in cigarettes and badly tuned automobile engines. It is produced commercially as synthesis gas by the re-forming reaction (Section 14.3). Carbon monoxide is the formal anhydride of formic acid, HCOOH, and the gas can be produced in the laboratory by the dehydration of formic acid with hot, concentrated sulfuric acid ... 

Since initiation with conventional Friedel-Crafts halides cannot be controlled, the fine-tuning of reactions becomes extremely cumbersome. In contrast, by the use of alkylaluminum compounds elementary events (initiation, termination, transfer) become controllable and thus molecular engineering becomes possible. Indeed, by elucidating the mechanism of initiation etc., a large variety of new materials, i.e., block3, graft4-6 bigraft7 copolymers, have been synthesized and some of their physical-chemical properties determined. 

One should note the use of engineering units in the controller tuning parameters. The units become important when one must compare different controllers tuning parameters using different units for the PID calculation. 

The first engines invented by Rudolf Diesel ran on groundnut oil, but because of the advent of relatively cheap oil this type of biodiesel never became commercially viable. Since about 1930 the diesel engine has been refined and fine tuned to run on the diesel fraction of crude oil, which consists mainly of saturated hydrocarbons. For this reason the modem diesel engine cannot run satisfactorily on a pure vegetable oil feedstock because of problems of high viscosity, deposit formation in the injection system and poor cold-start properties. Today, however, environmental... 

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