• International Journal of Automotive Technology
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• v.5 no.4
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• pp.311-319
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• 2004

There are many methods to test engine emissions depending on the regulations used such as FTP-75(CYS-75) mode, 10-15 mode and ECE-15 mode. Most of these modes consist of transient conditions such as cranking, rapid acceleration or deceleration modes. In this experimental research, the transient characteristics including cranking and accelerating mode in SI engines were studied to compare pure gasoline with methanol-reformulated fuels for performance and exhaust emissions. The results show that methanol-reformulated fuels have a better emissions reduction rate than that of pure gasoline especially for HC, CO and NOx emissions during cranking mode. The acceleration performances conform to the results of the distillation curve and the CO concentration for RM50 varies slightly in acceleration mode.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.43-49
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• 2001

In order to satisfy the ULEV emissions regulation, fast light-off of a catalyst is essential for reduction of HC and CO emissions during the cold start. Cranking Exhaust Gas Ignition(CEGI) method developed in this study showed that the catalyst reaches the light-off temperature in a few seconds. The CEGI stops the ignition signal for a few seconds during the cranking period, so the unburned fuel-air mixture bypasses the combustion chamber and flows through the exhaust manifold. When the unburned mixture reaches two glow plugs installed upstream of the catalyst, it burns and releases the thermal energy to heat up the catalyst, In the FTP-75 vehicle tests, the CEGI showed that the exhaust emissions reduced by 47.7% for THC and by 88.6% for CO in the cold-transient phase of the test.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.295-301
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• 2006

A new combustion method of high compression ratio SI engine was studied and proposed in order to achieve high thermal efficiency, comparable to that of CI engine. Compression ratio of SI engine is generally restricted by the knocking phenomena. A combustion chamber profile and a cranking mechanism were studied to avoid knocking with high compression ratio. Because reducing the end-gas temperature will suppress knocking, a combustion chamber was considered to have a wide surface at the end-gas region. However, wide surface will lead to large heat loss, which may cancel the gain of higher compression ratio operation. Thereby, a special cranking mechanism was adapted which allowed the piston to move rapidly near TDC. Numerical simulations were performed to optimize the cranking mechanism for achieving high thermal efficiency. An elliptic gear system and a leaf-shape gear system were employed in numerical simulations. Livengood-Wu integral, which is widely used to judge knocking occurrence, was calculated to verify the effect for the new concept. As a result, this concept can be operated at compression ratio of fourteen using a regular gasoline. A new single cylinder engine with compression ratio of twelve and TGV(Tumble Generation Valve) to enhance the turbulence and combustion speed was designed and built for proving its performance. The test results verified the predictions. Thermal efficiency was improve over 10% with compression ratio of twelve compared to an original engine with compression ratio of ten when strong turbulence was generated using TGV, leading to a fast combustion speed and reduced heat loss.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1193-1200
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• 2001

There are many regulation test methods to be related with engine emissions such as CVS-75, D-13, ECE-15 modes and so on. Most of these modes are consisted of lots of transient conditions that have rapid acceleration, deceleration and cranking modes. In this experimental research, the engine characteristics of cranking, accelerating and power output in a S.I. engine were studied to compare with neat gasoline and alternative fuels of M30 (methanol 30%, aromatic series 32%, non-aromatic 38%) and M50 (methanol 50%, aromatic 30%, non-aromatic 20%) for performance and exhaust emissions. The results show that reformulated methanol fuels are better emissions reduction of 15.7% over than that of neat gasoline fuel especially in HC and CO emissions at cranking mode. And the accelerating performances coincide with the results of distillation curve. CO concentration for M50 fuel is varied in a just little for the condition of slow acceleration. At wide-open throttle condition, brake specific energy consumption of reformulated fuels is increased and thermal efficiency is some what lower than that of gasoline fuel.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1297-1302
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• 2018

Propose of this study was to compared and analyzes the cranking between the newly developed hand cycle prototype and the hign-end hand cycle that are sold on the market for the disabled athletes. For this study, 10 male subjects, who had the same type of disability, were selected from the Korea Disabled Cycle Federation. 12 infrared camera(Oqus-500) was utilized to acquire the subjects' kinematic data. we have analyzed the data of 30 seconds - 15 seconds before and after cranking. SPSS 16 was used for a statistical verification and the difference of the sports biomechanical variable between RX and the prototype was verified by utilizing pared samples t-test. The significance level at the time of the experiment was ${\alpha}=.05$. The results show that there is a need to design the hand cycle crank in a curve shape to lessen the muscle fatigue that is measured the highest between the angle of 180 to 195. In addition, comparative analysis between the existing data and the data of modified crank must be researched since the hand cycle cranking is one of the main variables in performance enhancement.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.64-70
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• 2007

Raising exhaust gas temperature during cold-start period is very crucial to improve emission performance of SI engines because it enhances the performance of catalyst in the early stage of engine start. In this study, control variables such as ignition timing, idle speed actuator(ISA) opening and fuel injection duration were extensively investigated to analyze variations in exhaust gas temperature and engine stability during cranking period. Experimental results showed that spark timing affected engine stability and exhaust gas temperature but the effects were small. On the other hand, shortened injection duration and increased ISA opening led to a significant increase in exhaust gas temperature. Under such conditions, increase in cranking time was also observed, showing that it becomes harder to start the engine. Based on these observations, a pseudo fuel-air ratio, defined as a ratio of fuel injection time to degree of ISA opening, was introduced to analyze the experimental results. In general, decrease in pseudo fuel-air ratio raised exhaust gas temperature with the cost of stable and fast cranking. On the contrary, an optimal range of the pseudo fuel-air ratio was found to be between 0.3 to 0.5 where higher exhaust gas temperatures can be obtained without sacrificing the engine stability.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.133-138
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• 2011

Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Therefore, uniformity of compression pressure and valve timing became one of most important engine design and production standard. Conventional method to evaluate compression pressure uniformity is to measure each cylinder pressure by mechanical pressure gage during cranking. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and also causes high manhour and cost. To check valve timing, related FEAD parts should be disassembled and timing mark should be checked manually. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. With this new methodology, possibility to detect leaky cylinder and wrong valve timing was observed.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.45-50
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• 2011

Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.32-39
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• 2000

To optimize the cold start process of a 4-stroke, 8 cylinder Diesel engine, a dynamic simulation model from cranking to idle speed is developed. Physically-based first order starter motor dynamics are used to model the performance of starting process which is very complex. These equations are solved using numerical schemes(Petzold-Gear BDF method) to describe the starting process of diesel engine and to study the effects of starting parameters. The validity of this model is examined by start test. This model can be served as a tool for computer aided control systems design to improve cold improve cold start performance.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.69-77
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• 1998

In order to meet the stringent emission regulations, fast light-off of a catalyst is essential to reduce the HC and CO emissions during cold start. Cranking Exhaust Gas Ignition (CEGI) method developed in this study showed that the catalyst reaches the light-off temperature in a few seconds after cold start. The CEGI system cuts off the ignition signal for a few seconds during the cranking period. so the unburned fuel-air mixture bypasses the combustion chamber and flows through the exhaust manifold. When the unburned mixture reaches two glow plugs installed upstream of the catalyst, it burns and releases the thermal energy to heat up the catalyst. Results from the FTP-75 tests showed that the exhaust emissions with the CEGI reduced by 47.7% for THC and by 88.6% for CO in the cold-transient phase of the test.