#19 Car Engines – How Camshafts Work

     In the previous automotive article, we learnt about The 4 Stoke Cycle which involves the opening and closing of camshafts as the cylinders move up and down.

     But, did you know the typical car engine running at more than 4000 RPM have valves opening and closing for more than 2000 times per minute, or, 33 times per second?

     How do they work and why is this so? Continue to read on to find out more.

     As the camshaft spins, the lobes open and close the intake and exhaust valves in time with the motion of the piston. Before understanding the whole process, look at the instantaneous motion of the piston in relative to the valves’ opening and closing from time to time.

     When the piston moves downward in the intake stroke, the intake valve opens. It opens to enable more air to come in and fuel to be injected into the space as the piston descends to the bottom. The intake valve would close right as the piston bottoms out.

     On the other hand, just as the piston bottoms out, the exhaust valve would open to enable the release of waste exhaust.

     A Single Overhead Cam Engine (SOHC) denotes an engine with one cam per head. For SOHC engine with an inline 4-cylinder or inline 6-cylinder, it will have one cam. Meanwhile, for V6 or V8 configurations, it will have two cams per head.

SOHC

     A Double Overhead Cam Engine (DOHC) has two cams per head. So inline engines have two cams, and V engines have four. One of the obvious reasons to use double overhead cams is to allow the usage of more intake and exhaust valve. More valves denote the gases can flow more freely with more opening for them to flow through. Hence, producing higher power output.

DOHC

     As mentioned earlier, DOHC engine allows the usage of more valves per cylinder. If a SOHC engine could allow 4 valves per cylinder, let say, having a DOHC engine would not be useful as it carries an additional weight.

     In order to promote effective and efficient combustion, DOHC engines are equipped with a spark plug located in the middle of the combustion chamber.

     On the contrary, a SOHC engine has its camshaft placed in the middle of the head in order to drive both the intake and exhaust valves.

     As a result, the spark plug could not be located at the optimum location as DOHCs do. Below is the comparisons of the pros and cons of both types of engines.

  

SOHC	DOHC
Better starting torque    Lower peak torque and horsepower	Lower starting torque (Additional weight of valve trains)     Greater peak torque and horsepower   Easier to implement variable valve timing technologies.

     A pushrod engine has similar configurations to SOHC and DOHC engines. The valves are located in the head, above the cylinder. The key difference is that the camshaft is inside the engine block, rather than in the head.

     We learned a great deal about the operations of camshafts today. It is all how the camshafts and crankshafts are synchronized by a connector known as the timing belt.

     Next, we looked at how the SOHC and DOHC engines work by comparing their characteristics. Lastly, we get to know the pushrod engine in frivolous manner.

     In the next automotive article, we will look at how a car’s suspensions work. The article consists of two parts and the first edition of it will cover several topics such as the suspensions parts, components, etc. Be sure not to miss one of the most unmissable automotive article yet!

Source:  www.auto.howstuffworks.com

               www.paultan.org

By: Vincent Ti

#18 X = Work Hard + 1

     Work gives you meaning and purpose and life is empty without it – Stephen Hawking. Professor Stephen Hawking may not be an expert in character edification but you never call him a genius for nothing.

The author believes that owning a car like the BMW X1 needs passion, perseverance and dedication to one's work. That's how the title of the article comes by: X = Work Hard + 1

     Among his publications of the gravitational singularity theorems and black holes theory, have shed light on the studies of general relativity and quantum gravity.

     Raw talent and individual brilliance may not be good enough to achieve that cause if without effort, struggle and endeavor in the process.

      It does not mean we are obliged to certain tasks all the time, but having a sense of responsibility towards a job simply gives us the gratification.

     According to Hawking, not having purpose and ambition in one’s life is identical to the dead fish swimming with the stream. In other words, you are not working towards your goal.

     If you ask for my opinions, a person’s success is not measured merely on his or her fortunes or achievements, but also on the contributions being dedicated from day number one. Because, for me, the gains achieved through sweats and perseverance outweigh the sole numerical values of wealth.

     Money is very important and everybody loves money. We know that money is very hard to earn. Yet, we often spend more and faster than we can earn. Then it comes to a point that, if we work hard enough to earn more money, but at the same time, work hard to spend them, we are left with nothing at the end.

     It does not matter how much we can earn anymore, because the rate of our spending is equal to or more than the rate we earn on regular basis. By putting everything into perspective, we let our sources of wealth slip out from our fingers unnecessarily.

     You may wonder if my points have deviated slightly from the main topic today. In fact, our lifestyles are much more complicated than the people living in the past. We are surrounded by a wide array of temptation.

     As our spending power increases, we have less hesitation when spending. Therefore, proper financial management skills should be well-equipped to resist the lure of excessive spending habits.

     Here is the three golden rules that guide us to get what we want through hard work:

      1) Pursue your dreams, otherwise you will never taste the rewards forever.

2) Dare to ask for what you want, otherwise the answer will always be no.

      3) You must move forward, otherwise you will always be in the same place.

     When we were still kids, our parents constantly educated us to study diligently in order to become successful. But things do not appear as simple as they look; we gradually realize that successes in life will not come if they are not accompanied by hard work and perseverance.

     Just like how you dream of becoming a proud owner of a luxury car, you cannot just sit down and do nothing hoping that the imagination will come true one day.

     Every person has a different viewpoint of life but eventually coalesce into a similar single objective – to live better. There is no shortcut for it and the solitary golden rule to achieve that lies on the meaning of few words. Never fear hard work.

By: Vincent Ti

#17 All that Glitters is not Gold

     Not long ago, I attended a seminar that highlights the typical human responses when facing with shocks, surprises and fears in untoward circumstances. The emcee stressed out a few important points which I would like to feature today.

In his speeches, he mentioned there are noticeable changes in every human’s brain activity in event of agitation, panic and hysteria. 

While they are all the normal reactions resulted from human’s nature to navigate something undesirable and keep sweet memories in their lives, somehow, we are able to make judgement between the good and poor, he added.

Upon hearing his statements, I was amazed at how our body responds to every change around us in a matter of seconds! Just like how our body reacts when seeing something attractive, we will automatically take a closer look or spend more time admiring them. This is because our body secretes the hormones that tell us of that physically alluring, captivating object.

Well, I realized it was true indeed that we are obsessed and more likely to engage in the beauty or physical appearance of everything. We always have one eye blinded when facing with someone or something we find aesthetically pleasant.

At this stage, our mind would most probably focus intently on that single entity and often on little else. Anyway, are everything that look good in picture truly reflect the way they behave in reality?

I am really running out of words to describe my feelings and struggled to make my lines coherent today. Because the idiom reminded me of the ordeals I had had in the past. I was pretty a novice back then, believing in a fake relationship, hoping that all the promises will come true which turned out to be the exact opposite.

The incident felt like a big slap on the wrist for me. ‘‘Just because a petite woman who look naive and gullible doesn’t mean she won’t cheat’’, I told myself in heart. All in all, all that glitters is not gold and it will be wise to judge someone based on visual perceptions instead of pure visual beauty. Recalling an agony like this made me thought something in Chinese slang…

By: Vincent Ti

#16 Small Matters, Big Problems

A minor hitch can grow into severe glitch if it is not properly managed

     Back then when I was younger, I had a very nonchalant attitude. I ended up having the kitchen stoves unchecked, the door locks improperly secured, working halfway and go AWOL. My parents strictly condemned my acts but those rebukes were never effective in morphing my transgressions. It was never – at least until I started working outside and had a real taste of the hostile working environment.

     At home, I have almost everything panned out for me and did not realize the labour behind all the perfectness. While working for an employer, my works was expected to be near perfect and faultless. I rarely had the time to take a break in between working hours or simply apply for leave according to my wish. That’s the brutality of working outside, I recalled.

Avoid tense situation, don't let problems exaggerate

     It is because of my insouciant and carefree attitude towards every detail in my life that resulted in difficulties in adapting to the society. The point is, if we can learn something meaningful in advance, don’t wait and delay until the eleventh hour.

     This is because we only get to know something the moment we feel we need that particular skills at certain point of our lives, it may be well too late. Because a problem usually appear to be small and irrelevant at first, only to propagate and magnified as time passes.

     Just as what I did in my younger times, I felt that all the unsecured door locks, unchecked stoves was insignificant. Only when I started meeting people then I began to realize the importance of taking every minor details in life in earnest.

     In reality, there are dozens of instances where a serious problem arise from the smallest conflicts – ever. One of them could apply to the conflicts in communication between human. Even when there are slight misunderstandings in a conversation, the tension would escalate between both parties if it is not resolved harmoniously.

     At this point, the tension would lead to an exchange of hostilities perhaps to a critical extent. Richard Templar, in The Rules of Life say almost the same thing: ‘‘Retaliation can only lead to an escalation of hostilities in a conflict’’. Templar believes that retaliation does not promote accord, it evokes resentment.

     The same rule applies to every aspect of our lives indeed. Just to think of this example to make us understand better. A tiny flaw or any imperfection to a building structure makes the designs fragile. If something is not done to correct it, a bigger problem would occur. The problem with most of us is that often, we learn about damage limitation but not the ways to cease small matters from evolving to become big problems.

     It sounds incredibly boring if I merely include all the facts and life experiences in my blog posts. Sometimes, even the simplest of stories can provide the most meaningful way to guide us to get what we want in life.

By: Vincent Ti