INSTRUCTION: This paper consists of SIX (6) structure questions. Answer any FOUR (4) questions.

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1 INSTRUCTION: This paper consists of SIX (6) structure questions. Answer any FOUR (4) questions. ARAHAN: Kertas ini mengandungi ENAM (6) soalan struktur. Jawab mana mana EMPAT (4) soalan. QUESTION 1 SOALAN 1 CLO1 (a) List FOUR (4) characteristics of CI engine. Senaraikan EMPAT(4) ciri-ciri enjin penyalaan mampatan. [4 marks] [4markah] CLO1 (b) Describe the process of the two stroke CI engine cycle. Huraikan proses kitaran enjin dua lejang jenis nyalaan mampatan. [6 marks] [6 markah] CLO1 (c) Explain the process of gas turbine cycle with a schematic diagram. Terangkan proses kitaran turbin gas beserta gambarajah skematik. [15 marks] [15 markah] 2

2 QUESTION 2 SOALAN 2 (a) Define compression ratio, r v as in Otto Cycle. Jelaskan maksud nisbah mampatan, r v di dalam kitar Otto. [2 marks] [2markah] C3 (b) Sketch a P-V diagram for Otto Cycle, Diesel cycle and Dual Cycle and list TWO (2) differences in the processes involved. Lukiskan gambarajah P-v bagi kitar Otto, kitar Diesel dan kitar Kembar, dan senaraikan DUA (2) perbezaan dari segi proses yang terlibat. [8 marks] [8markah] C4 (c) A compression ignition engine has an inlet temperature and a pressure at 20 C and 1.5 bar respectively. The compression ratio is 8/1 and the maximum cycle temperature is 1500 C. Calculate the air standard thermal efficiency based on the diesel cycle. Sebuah enjin pencucuhan mampatan direkodkan mempunyai suhu masukan dan tekanan pada 20 C dan 1.5 bar. Nisbah mampatan pula adalah pada 8/1 dan suhu maksimum bagi kitaran adalah 1500 C. Kira kecekapan udara piawai berdasarkan pada kitar diesel. [15 marks] [15 markah] 3

3 QUESTION 3 SOALAN 3 (a) Briefly explain the knocking occurrence in a spark ignition engine and its effects when the engine is operating. Terangkan secara ringkas tentang fenomena ketukan di dalam enjin enjin penyalaan percikan dan kesannya ketika enjin beroperasi. (b) List FIVE (5) factors that contribute to knocking in an engine. Senaraikan LIMA (5) faktor yang menyebabkan berlakunya ketukan di dalam sesebuah enjin. (c) With an aid of a diagram pressure vs. crank angle, explain the definition of ignition delay. Dengan bantuan gambarajah tekanan melawan sudut engkol, terangkan maksud perlambatan penyalaan. (d) There are three stages of combustion in a spark ignition engine. They are ignition lag, main combustion stage and afterburning. This can be observed in the Figure 3.1. Terdapat tiga peringkat pembakaran di dalam enjin penyalaan percikan seperti perlambatan penyalaan, pembakaran utama dan selepas pembakaran. Peringkatperingkat ini dapat dilihat dari Rajah

4 Figure 3.1. Based on the above statement, explain the phenomenon of main combustion as labelled at stage II. Berdasarkan peryataan di atas, terangkan fenomena pembakaran utama seperti yang dilabelkan peringkat II. (e) Identify FIVE (5) factors which are influencing the period of ignition lag. Kenalpasti LIMA (5) faktor yang mempengaruhi jangka masa perlambatan penyalaan. 5

5 QUESTION 4 SOALAN 4 (a) Define the indicated power (i.p), brake power (b.p) and friction power (f.p). Terangkan maksud kuasa tertunjuk (i.p), kuasa brek (b.p) dan kuasa geseran (f.p). [6 marks] [6 markah] C3 (b) Sketch the line which are indicated power (i.p), brake power (b.p) and friction power (f.p) in a graph of power vs engine speed. Lakarkan garisan-garisan kuasa tertunjuk(i.p), kuasa brek (b.p) dan kuasa geseran (f.p) pada graf kuasa melawan kelajuan enjin. [8 marks] [8 markah] C4 (c) A four cylinder petrol engine has a bore diameter of 57 mm and a stroke of 90 mm. Its rated speed is 2800 rev/min and brake load of 170 N. The brake power is 16.2 kw. A Morse test is carried out and the cylinders are cut out in the order of 1,2,3 and 4 with each corresponding brake loads of 126 N, N, N and 126 N respectively. Calculate: Sebuah enjin petrol empat silinder mempunyai diameter kebuk 57 mm dan lejang 90 mm. Ia berkelajuan 2800 psm dan beban brek 170 N. Kuasa brek ialah 16.2 kw. Ujian Morse dilakukan dengan mematikan silinder mengikut turutan 1,2,3 dan 4 dengan beban brek masing-masing 126 N, N, N dan 126 N. Kirakan : i. Brake min effective pressure, b.m.e.p Tekanan berkesan min brek, b.m.e.p ii. Total Indicator load, I Beban tertunjuk keseluruhan, I iii. Mechanical efficiency Kecekapan mekanikal [11 marks] [11 markah] 6

6 QUESTION 5 SOALAN 5 (a) Explain the purpose of why cylinder head is produced. Terangkan tujuan kepala silinder dihasilkan. [2 marks] [2 markah] (b) List the materials used in making a cylinder head. State the reason for selecting the material respectively. Senaraikan bahan yang digunakan untuk membuat kepala silinder. Nyatakan sebab mengapa bahan tersebut dipilih. [8 marks] [8 markah] (c) Identify SIX (6) parts of components found in a cylinder head. Kenalpasti ENAM (6) bahagian komponen yang terdapat dalam kepala silinder. [6 marks] [6 markah] C3 (d) Name TWO (2) processes of manufacturing a cylinder head. Namakan DUA (2) proses pembuatan kepala silinder. [2 marks] [2 markah] (e) Sketch and label the FIVE (5) parts found in Controlled Vortex Combustion Chamber (CVCC). Lakarkan dan labelkan LIMA (5) bahagian komponen yang terdapat pada Ruang Pembakaran Vortex Kawalan (CVCC). [7 marks] [7 markah] QUESTION 6 7

7 SOALAN 6 (d) Explain the function of piston in an engine and name ONE (1) commonly used material for the piston. Jelaskan fungsi omboh di dalam enjin dan namakan SATU (1) bahan yang biasa digunakan untuk membuat omboh. [3 marks] [3 markah] C3 (e) Sketch and label FOUR (4) types of the compression ring. Lakarkan dan label EMPAT (4) jenis bentuk gegelung mampatan. (f) List TWO (2) functions of the following components: Senaraikan DUA (2) fungsi komponen berikut: i. Compression Rings Gegelung mampatan ii. Oil Ring ii. Gegelung minyak. (g) Name and explain TWO (2) types of valve arrangement. Namakan dan terangkan DUA (2) jenis susunan injap. [8 marks] [8 markah] [4 marks] [4 markah] [6 marks] [6 markah] 8

(h) Figure 1 shows the zone of the heat and working temperature of the exhaust valve. Identify temperature of each zone on the valve as shown by the alphabets.

8 (h) Figure 1 shows the zone of the heat and working temperature of the exhaust valve. Identify temperature of each zone on the valve as shown by the alphabets. Rajah 1 di bawah menunjukkan zon haba dan suhu kerja injap ekzos. Kenal pasti suhu setiap zon pada injap seperti yang ditunjukkan pada huruf tersebut. B A C D Figure 1 [4 marks] [4 markah] SOALAN TAMAT 9

INSTRUCTION: This section consists of SIX (6) essay questions. Answer FOUR (4) questions only.

INSTRUCTION: This section consists of SIX (6) essay questions. Answer FOUR (4) questions only. ARAHAN: Bahagian ini mengandungi ENAM (6) soalan esei. Jawab EMPAT (4) soalan sahaja. QUESTION 1 SOALAN 1